PRODUCT DESIGN IMPROVEMENT THROUGH INTEGRATION OF THEORY OF INVENTIVE PROBLEM SOLVING (TRIZ) AND DESIGN FOR MANUFACTURE AND ASSEMBLY (DFMA) MUNIRA BT MOHAMED NAZARI A project report submitted in partial fulfillment of the requirements for the award of the degree of Master of Mechanical Engineering (Advanced Manufacturing Technology) Faculty of Mechanical Engineering Universiti Teknologi Malaysia APRIL 2010 iii For my dad, mum, bro and sis, Thank you for your love and support as well as funding me some valuable money. Alhamdulillah, I managed to complete this project in time and without any hindrances. For all my beloved friends especially Mardianaliza, Norhazilina, Kak Aznee, Kak Siti and Suliana, Your help and kindness are so precious and irreplaceable with any valuable thing. For my Master Project supervisor, Dr. Ariffin Abdul Razak, Your commitment and advices are really helpful in completing this Master Project. iv ACKNOWLEDGEMENTS All praises to the Al-Mighty Allah S.W.T, The Merciful and Beneficent for the strength and blessing throughout the entire time until completion of this Master Project report. Peace be upon our prophet Muhammad S.A.W, whose has given light to mankind. Firstly, I wish to express my sincere appreciation and gratitude to my Master Project supervisor, Dr. Ariffin Abdul Razak for his guidance, counsels and for putting much effort through his useful advice in this Master Project. Secondly, I wish to give a special thank to Mr. Idris and Mr. Arman Syah for their kindness in sharing the valuable information in starting this project. I am also would like to thank to all my colleagues who are always giving me support and help when I am lost. May ALLAH repay their sincere kindness. Lastly, for each and everyone who involved either directly or indirectly in this Master Project, their contribution is highly appreciated. The kindness corporation and support from all of the above mentioned people would always be remembered. Thank you. v ABSTRACT Theory of Inventive Problem Solving (TRIZ) is one of the Value Engineering (VE) systematic tools to improve the value of products by examination of function, by which designer can systematically solve problems and enhance decision-making. Design for Manufacture and Assembly (DFMA) is an approach to improve product performance and to simplify product. This project report describes work to integrate DFMA and TRIZ to improve and value added the current design of consumer product. The used of TRIZ concept will eliminate the contradiction problem that occurred during the process of improvement of the product by applying the principles proposed by TRIZ. TRIZ had simplified 39 standard technical characteristics that cause conflict. These are called the 39 Engineering Parameters. The conflict then can be solved by referring to the 40 Inventive Principles. Results from case studies showed that the integrating of DFMA and TRIZ can improve the product design efficiency value, minimize assembly complexity, reduce the overall assembly time and cost, and reduce the number of part in product improvement compared by just using single tool. vi ABSTRAK Teori Mencipta Penyelesaian Masalah (TRIZ) adalah salah satu peralatan sistematik dalam Kejuruteaan Nilai (VE) untuk meningkatkan nilai sesuatu produk dengan menganalisakan fungsinya, di mana pereka dapat menyelesaikan masalah secara sistematik dan keputusan yang dibuat dapat ditingkatkan. Sementara itu, Rekabentuk untuk Pembuatan dan Pemasangan (DFMA) adalah kaedah untuk meningkatkan keupayaan produk dan memudahkan rekabentuk produk. Dalam laporan ini, kerja untuk meningkatkan keupayaan produk dan penambahan nilai untuk rekabentuk produk pengguna terkini dihuraikan dengan menggunakan kaedah pergabungan di antara (DFMA) dan (TRIZ). Penggunaan konsep (TRIZ) akan menghapuskan percanggahan masalah yang dihadapi semasa proses meningkatkan nilai produk dengan mengaplikasikan prinsip yang dicadangkan oleh (TRIZ). (TRIZ) telah menyimpulkan 39 sifat teknikal yang boleh menyebabkan konflik. Ia dipanggil 39 Parameter Kejuruteraan. Walaubagaimanapun, konflik tersebut dapat diselesaikan dengan merujuk kepada 40 Prinsip Mencipta. Keputusan daripada kajian menunjukkan pergabungan di antara (DFMA) dan (TRIZ) akan meningkatkan nilai kecekapan rekabentuk produk, meminimakan kekompleksan pemasangan, mengurangkan masa dan kos pemasangan, dan mengurangkan bilangan jumlah bahagian dalam pembangunan produk berbanding dengan hanya mengunakan satu peralatan sahaja. vii TABLE OF CONTENTS CHAPTER 1 TITLE PAGE DECLARATION ii DEDICATION iii ACKNOWLEDGEMENT iv ABSTRACT v ABSTRAK vi TABLE OF CONTENTS vii LIST OF TABLES xiii LIST OF FIGURES xiv LIST OF ABBREVIATIONS xvi LIST OF SYMBOLS xvii LIST OF APPENDICES xviii INTRODUCTION 1 1.1 Introduction to the problem 1 1.2 Objectives 2 1.3 Scope 2 1.4 Methodology of study 3 viii 2 1.5 Significant of study 5 1.6 Report structure 5 1.7 Summary 6 LITERATURE REVIEW 7 2.1 Introduction 7 2.2 Value Engineering 8 2.2.1 What is Value Engineering? 8 2.2.2 The Job Plan 9 2.2.3 How it Works? 11 2.3 Theory of Inventive Problem Solving (TRIZ) 12 2.3.1 History of TRIZ 12 2.3.2 What is TRIZ? 12 2.3.3 TRIZ Fundamental 13 2.3.3.1 Ideality 13 2.3.3.2 Functionality 14 2.3.3.3 Resource 15 2.3.3.4 Contradictions 17 2.3.3.5 Evolution 22 Additional TRIZ Tools 23 2.3.4 2.3.4.1 ARIZ (Algorithm for Inventive Problem Solving) 24 2.3.4.2 Su-Field Analysis 24 2.3.4.3 Anticipatory Failure Determination (AFD) 2.3.4.4 Directed Product Evolution (DPE) 2.3.5 25 Integration TRIZ with Others Problem Solving Tools 2.4 24 27 Design for Manufacture and Assembly (DFMA) 29 2.4.1 What is DFMA? 29 2.4.2 The DFMA Approach 30 ix 2.5 3 Summary TRIZ CONCEPT 33 3.1 Introduction 33 3.2 General TRIZ Process Procedures 34 3.2.1 Problem Definition 34 3.2.2 Problem Classification and Tool Selection 36 3.2.3 Solution Generation 37 3.2.4 Concept Evaluation 38 3.2.5 TRIZ Tool Selection 38 3.3 Technical Contradiction Elimination – Inventive Principle Method 38 3.3.1 Identify the Problem 39 3.3.2 Formulate the Problem 40 3.3.3 Previously Well-Solved Problem 41 3.3.4 Look for Analogous Solutions & Adapt To the Solution 3.4 4 32 Summary 41 45 PRODUCT CASE STUDY 46 4.1 Introduction 46 4.2 Product as Case Study 47 4.2.1 Product Selection 47 4.2.2 Product Tree Structure 48 4.2.3 Part ID Number 50 4.2.4 Assembly Sequence 51 4.3 Part Critique 51 4.4 Summary 56 x 5 6 DESIGN FOR ASSEMBLY (DFA) ANALYSIS FOR ORIGINAL DESIGN 57 5.1 Introduction 57 5.2 Classification of Product parts 58 5.3 Theoretical Minimum Parts Assessment 59 5.4 DFA Worksheet 60 5.5 Result 62 5.6 Summary 63 PROPOSED IMPROVEMENT OF NEW DESIGN USING DFMA METHODOLOGY AND TRIZ CONCEPT 64 6.1 Introduction 64 6.2 Improvement by Using DFMA Methodology 65 6.2.1 Improvement 1: Connector 65 6.2.2 Improvement 2: Wiper Holder 66 6.2.3 Improvement 3: Male Adjuster 67 6.2.4 Improvement 4: Female Adjuster 68 6.2.5 Improvement 5: Stopper 69 6.2.6 Improvement 6: Rod A 70 6.2.7 Improvement 7: Handle 71 6.2.8 Improvement 8: Joint 71 6.2.9 Improvement 9: Snap Fit Shaft 72 6.3 6.2.10 Improvement 10: Pusher 73 Improvement by Using TRIZ Concept 74 6.3.1 Improvement1: Pusher 74 6.3.2 Improvement 2: Male and Female Adjuster 75 6.3.3 Improvement 3: Joint 6.3.4 Improvement 4: Wiper Holder, Connector, 76 xi Arms and Pins 6.4 7 79 DFMA AND TRIZ ANALYSIS FOR NEW DESIGN 80 7.1 Introduction 80 7.2 DFMA Analysis for New Design 81 7.2.1 Classification of Product Parts 82 7.2.2 Theoretical Minimum Parts Assessment 83 7.2.3 DFA Worksheet 83 7.2.4 Result 85 7.2.5 DFM Analysis 86 7.3 7.4 8 Summary 77 TRIZ Analysis for New Design 87 7.3.1 Classification of Product Part 88 7.3.2 DFA Worksheet 89 7.3.3 Result 90 7.3.4 DFM Analysis 91 Summary 91 DISCUSSION 92 8.1 Introduction 92 8.2 Comparison of Product Case Study Result 93 8.2.1 Comparisons of DFMA Analysis Result 93 8.2.2 Comparisons of TRIZ Analysis Result 95 8.2.3 Comparisons between DFMA and TRIZ Improvement Result 8.3 Summary 98 99 xii 9 CONCLUSION 100 9.1 Introduction 100 9.2 Recommendations for Future Work 101 9.3 Concluding Remark 103 REFERENCES 105 APPENDICES 108 xiii LIST OF TABLES TABLE NO. TITLE PAGE 2.1 VE evaluation process. 11 2.2 Table of 39 parameters of contradiction 18 2.3 Table of 40 inventive principles 19 2.4 Pattern of evolution of technological systems 25 3.1 Table characteristic of beverage can through Innovative Situation Questionnaire 40 4.1 The Sponge Mop part ID number 50 4.2 Part critique of each part for Sponge Mop 52 5.1 Classification of Part for Original Design 58 5.2 DFA worksheet analysis for original design 60 7.1 Classification of Part for New Design by DFMA Methodology 7.2 82 DFA worksheet analysis for new design by DFMA Methodology 84 7.3 Classification of Part for New Design by TRIZ Concept 88 7.4 DFA worksheet analysis for new design by TRIZ 89 8.1 Effect of the improvement 93 8.2 Result of time saving due to the factor of design change 94 8.3 Effect of the improvement result 95 8.4 Effect of the integration improvement 98 xiv LIST OF FIGURES FIGURE NO TITLE PAGE 1.1 Flow chart of the project activities for MP 1 and MP 2. 4 2.1 Three steps to pre-analyze the conflict. 21 2.2 Curves of technical system evolution. 23 2.3 Integration of design problem-solving tools. 28 3.1 Four steps TRIZ process procedure. 34 3.2 Technical Contradiction Elimination – Inventive Principle step-by-step. 39 3.3 Result for the problem. 42 3.4 Cross section of corrugated can wall. 43 3.5 Spheroidality Strengthens Can's Load Bearing Capacity. Perpendicular angle has been replaced with a curve. 44 4.1 Sponge Mop. 48 4.2 Sponge Mop product tree structure. 49 6.1 Design improvement of Connector. 66 6.2 Design improvement of Wiper Holder. 67 6.3 Design improvement of Male Adjuster. 68 6.4 Design improvement of Female Adjuster. 69 6.5 Design improvement of Stopper. 70 6.6 Design improvement of Rod A. 70 6.7 Design improvement of Handle. 71 6.8 Design improvement of Joint. 72 6.9 New part design of Snap Fit Shaft. 73 xv 6.10 Improvement of Pusher quantity from two into one. 6.11 New design of Pusher by combining two pushers into one. 75 6.12 (a) New design of male adjuster with lock leaf, and (b) New design of female adjuster with lock slot. 6.13 78 Exploded drawing of new design of Sponge Mop via DFMA methodology 7.2 78 New design of wiper holder that designing to fit with the new connector design. 7.1 76 New design of connector based on idea from element in Principle 1. 6.14 73 81 Exploded view of new design of Sponge Mop via TRIZ concept 87 xvi LIST OF ABBREVIATIONS TRIZ - Theory of Inventive Problem Solving VE Value Engineering - DFMA - Design for Manufacture and Assembly MP 1 - Master Project 1 MP 2 - Master Project 2 DFA Design for Assembly - DFM - Design for Manufacture VA Value Analysis - ARIZ - Algorithm for Inventive Problem Solving QFD Quality Function Deployment - FMEA - Failure Mode Effect and Analysis 6σ - Six Sigma ID - Identification Q&A - Question and Answer TM - Assembly time CM - Assembly cost NM - Theoretical minimum number of part DE - Design efficiency xvii LIST OF SYMBOLS α - Alpha β - Beta n - Labor cost per second xviii LIST OF APPENDICES APPENDIX TITLE PAGE 1A Gantt chart 1: Project activities for Master Project Part 1 109 1B Gantt chart 2: Project activities for Master Project Part 2 110 2A Contradiction Table of 39 Parameters 111 2B The 40 Inventive Principles 117 2C DFA Worksheet 130 2D Table of Manual Handling Estimated Times 131 2E Table of Manual Insertion Estimated Times 132 2F Table of Compatibility between Processes and Materials 133 2G Table of Shape Generation Capabilities of Processes 134 7A Part Attributes of Each Part for New Design of Sponge Mop 7B Table of Primary Process and Material Selection for New Design 7C 136 Part Attributes of Each Part for New Design of Sponge Mop by TRIZ Concept 7D 135 138 Table of Primary Process and Material Selection for New Design by TRIZ Concept 139 CHAPTER 1 INTRODUCTION 1.1 Introduction to the Current Product Development Problem Now a day, product design simplification is important due to the rapid changing of customer demands, more competition and so on. Yet, manufacture is being forced to produce product that meet the customer requirement with high expectation such as product functionality but in lower cost. So, designer needs to design product with maximize value in order to fulfill that requirement. In recent decades the search for significant cost-saving effects that characterize major process innovations has driven manufacturers towards simplifying their products. In fact, when compared to process improvements in the production of complex assembled products, product innovations have a more profound impact on productivity, costs and quality [1]. Basically, there are two sort of problems for any given product design or process which are those where the solution is generally known and those where it is not. If the solution is generally known, it can be found in books, journals, or technical paper. Problems where the solutions are not generally known are called inventive problems and often offer contradiction requirements. Mostly, many people will 2 choose a compromised solution, where not all of the requirements are met and those that are met, are not optimized in order to resolve contradictory requirements or conflict [2]. In this case, there are several ways to solve the problem. The use of integrated several VE tools will help to resolve conflict and generate new solutions from outside the experience. 1.2 Objective To integrate Theory of Inventive Problem Solving (TRIZ) tool, and Design for Manufacture and Assembly (DFMA) methodology in order to improve and value added the current design of consumer product 1.3 Scope The study will focus on the: i) Application of DFMA methodology to identify detailed design problems and generate remedial design solutions. ii) Application of TRIZ method to improve the value added product development. iii) Consumer product as case study – Sponge Mop 3 1.4 Methodology of Study This thesis is conducted accordingly in two parts which is Master Project 1 (MP 1) in semester 1 and Master Project 2 (MP 2) in semester 2 as shown in Figure 1.1. The flow chart showed clearly the processes of the thesis activities in order to meet the time constrain. After the project had determined, the literature review on VE, DFMA and TRIZ methodology are studied in the early stage. The studies are done by reviewing the related books, journals and articles. For a while, the consumer product for the project analysis purpose is also been selected. The selected product then is been evaluated by using DFMA methodology and from the results some improvements are proposed. However, the proposed improvement activities will be continuing also in the MP 2. It is continuously process as in the stage of evaluation the new design with using integrated VE tools, it may have some unsuitability idea. So, the others proposed improvement need to do. Lastly, the discussion and conclusion will be done after the accurate analysis result on the new design is evaluated where, the new design of integration tools is compared to the new design of DFMA methodology in terms of percentages of part count reduction and design efficiency increment. 4 Literature Review on DFMA and TRIZ Methodology Discussion of the Both Designs Figure 1.1: Flow chart of the project activities for MP 1 and MP 2. 5 1.5 Significant of Study The significant of this thesis is to prove the use of integration of VE tools will give a better result of product design in term of simplification, product cycle life, efficiency, quality, function and also product value. In this thesis, product design improvement is done by integration of TRIZ and DFMA methodology. Hopefully with the result of this study, it can give an overview to others about the advantages of using integration problem solving tool in product development and then will attract more organization to use this method for their product development purpose. The result of integration problem solving tools should achieve improvement better than single tool with the main improvement is to reduce assembly and manufacture process time and cost. However, in case the improvement in term of cost and time does not show much improvement, the others factor such as product simplification, function and life cycle should be considered. 1.6 Report Structure This thesis consists of nine chapters. Chapter 1 presents the introduction of the thesis, Product Design Improvement through TRIZ and DFMA methodology where the topic include are objective, scopes, methodology of study and significant of study of the project. The literature reviews in Chapter 2 reports on relevant previous findings that are related to the research and also the review of the related discusses topics. The detail information on the research methods and tools that will be used in the case study is explained in Chapter 3. For the Chapter 4, the data information of the product case study will be explained in details. The next chapter consists of the original data analysis of the product case study. In this Chapter 5, the DFMA Methodology is applied. The proposed improvement of the original data case 6 study then been discussed in Chapter 6. This chapter covers both of the selected design problem solving tools. The analysis of the new improvement of the product case study then discussed in Chapter 7. The discussion of the case study result is in Chapter 8, while the conclusion of the case study is concluded in Chapter 9. The time management of all activities for the MP, Product Design Improvement through VE and DfMA methodology project is shown in Gantt chart MP 1 (Appendix 1A) and Gantt chart MP 2 (Appendix 1B). 1.7 Summary Through this thesis, the objective of the project is hopefully achieved as expected which is contained the important result such as success to improve design of the product case study by applying the selected methods and also develop a product that have maximize value, convenience, suitable and easy to use by the consumer. On the other hand, this chapter is providing information about the aim for the rest of the chapter. CHAPTER 2 LITERATURE REVIEW ON VALUE ENGINEERING (VE) DESIGN FOR MANUFACTURE AND ASSEMBLY (DfMA) AND TRIZ METHODOLOGIES 2.1 Introduction This chapter discusses on the important of Value Engineering (VE) tools in product design, basic principle of the design problem solving tools which are TRIZ and DfMA methodologies, and also example the application of the both tool in simplify and improving product design. All discussing about the objectives of of this this related thesis project, topic actually Product Design Improvement through VE and DfMA methodology. The integration of TRIZ and DfMA is studied and applied in order to show how product can be improved into a maximize value. 8 2.2 Value Engineering The beginning decade of twenty first century witnessed several changes like world wide in technology management, restricting and down sizing global trade and competition, international quality standards, information exchange, lean manufacturing and virtual enterprises. In this age of globalization, the survival of any industry mainly depends on its cost of production and quality of its products. With the rapid growth of competition and shrinking product life cycle, Value Engineering (VE) has become an essential tool for getting a competitive edge. 2.2.1 What is Value Engineering? Value Engineering (VE) is a systematic tool to improve the “value” of goods or products and services by using an examination of function. Value is maximized by optimizing the equation: Value = Function / Cost Value can therefore be increased by either improving the function or reducing the cost. It is a primary tenet of VE that basic functions be preserved and not be reduced as a consequence of pursuing value improvement [3]. VE technique emerged during the years of World War II (1938-45) and was developed by Lawrence D Miles, a purchase engineer in General Electric Co. (GEC). In view of scarcity of vital defense material, he came up with the basic theme: “If I cannot get the product, I have got to get the function.” Thus, “function” grew in vitality and later matured into the development of the VE techniques. In 1947, this 9 approach was develop, refined and utilized in GEC and first known by the name Value Analysis (VA). VE is sometimes taught within the project management or industrial engineering body of knowledge as a technique in which the value of a system’s outputs is optimized by crafting a mix of performance (function) and costs. In most cases this practice identifies and removes unnecessary expenditures, thereby increasing the value for the manufacturer and/or their customers. VE uses rational logic (a unique "how" - "why" questioning technique) and the analysis of function to identify relationships that increase value. It is considered a quantitative method similar to the scientific method, which focuses on hypothesisconclusion approaches to test relationships, and operations research, which uses model building to identify predictive relationships. 2.2.2 The Job Plan Value engineering is often done by systematically following a multi-stage job plan. Lawrence Miles' original system was a six-step procedure which he called the "value analysis job plan." The plan consists of below six sequential steps: 1. Information Phase 2. Function Analysis Phase 3. Creative Phase 4. Evaluation Phase 5. Development Phase, and 6. Presentation & Implementation Phase 10 However, others have varied the job plan to fit their constraints. Depending on the application, there may be four, five, six, or more stages. One modern version has the following eight steps: 1. Preparation 2. Information 3. Analysis 4. Creation 5. Evaluation 6. Development 7. Presentation 8. Follow-up Four basic steps in the job plan are: • Information gathering - This asks what the requirements are for the object. Function analysis, an important technique in value engineering, is usually done in this initial stage. It tries to determine what functions or performance characteristics are important. It asks questions like; What does the object do? What must it do? What should it do? What could it do? What must it not do? • Alternative generation (creation) - In this stage value engineers ask; What are the various alternative ways of meeting requirements? What else will perform the desired function? • Evaluation - In this stage all the alternatives are assessed by evaluating how well they meet the required functions and how great will the cost savings be. • Presentation - In the final stage, the best alternative will be chosen and presented to the client for final decision. 11 2.2.3 How it Works? VE follows a structured thought process to evaluate options as follows. Table 2.1: VE evaluation process. STEP ACTION Gather information 1. What is being done now? Measure Who is doing it? What could it do? What must it not do? 2. How will the alternatives be measured? Analyze What are the alternate ways of meeting requirements? What else can perform the desired function? 3. What must be done? Generate What does it cost? 4. What else will do the job? Evaluate 5. Which Ideas are the best? 6. Develop and expand ideas What are the impacts? What is the cost? What is the performance? 7. Present ideas Sell alternatives 12 2.3 Theory of Inventive Problem Solving (TRIZ) Theory of Inventive Problem Solving was called TRIZ because regarding to the Romanized acronym for Russian words ‘Teoriya Resheniya Izobretatelskikh Zadatch’ which means ‘The theory of inventor’s problem solving’. Basically, TRIZ is a methodology, tool set, and knowledge base for generating innovative ideas and solutions for problem solving. TRIZ provides tools and methods for use in problem formulation, system analysis, failure analysis, and patterns of system evolution. TRIZ concept are difference to the techniques such as brainstorming (which is based on random idea generation), aims to create an algorithmic approach to the invention of new systems, and refinement of old systems [4]. 2.3.1 History of TRIZ It was developed by a Soviet engineer and researcher Genrich Altshuller and his colleague starting in 1946. At the age of 20, Altshuller developed his first mature invention – a method for escaping from an immobilized submarine without diving gear in year 1946. He then worked for the “Inventions Inspection” department of the Caspian Sea flotilla of the Soviet Navy in Baku in the late of 1940s. Atshuller’s job was to inspect invention proposals, help document them, and help others to invent. 2.3.2 What is TRIZ? Darrel Mann claims TRIZ is a combination of methods, tools, a way of thinking in the article entitled “Hands on Systematic Innovation” [5]. The goal of TRIZ is to achieve absolute excellence in design and innovation. In order to achieve absolute excellence, TRIZ has five key philosophical elements which are ideality, functionality, resource, contradictions and evaluation. Based on these philosophical elements, TRIZ developed a system of methods. This system of methods is a 13 complete problem definition and solving process. It is a four step process that starting with the problem definition, problem classification and tool selection, solution generation and end the process by concept evaluation. 2.3.3 TRIZ Philosophical Elements As discussed before, TRIZ has five key philosophical elements can be follow in order to achieve the absolute excellent design and innovation. Below are the details about the five key philosophical elements in TRIZ. 2.3.3.1 Ideality Ideality is defined in similar terms to ‘value’. It is typically defined as benefits divided by cost and harm. Ideality = Where, ∑ Benefits = sum of the values of systems useful functions. (Here the supporting functions are not considered to be useful functions, because they will not bring benefits to customer directly. We considering supporting functions are part of the costs to make the system work). ∑ Costs = sum of the expenses for systems performance. ∑ Harm = sum of “harms” created by harmful functions. 14 Regarding to the ideality equation, a higher ration indicates a higher ideality. Through this, when a new system achieve a higher ration than the old system, we can considered it as a real improvement. In TRIZ, there is a “law of increasing ideality,” which states that the evolution of all technical system proceeds in the direction of increasing degree of ideality. The ideality of the system will increase in the following factors: 1. Increasing benefits. 2. Reducing costs 3. Reducing harms 4. Benefits increasing faster than costs and harms. In terms of TRIZ, any technical system or product is not a goal in itself. The real value of the product/system is in its useful functions. Therefore, the better system is the one that consumes fewer resources in both initial construction and maintenance. When the ratio becomes infinite, we call that the “Ideal Final Result” (IFR). Thus, the IFR system requires no material, consumes no energy and space, needs no maintenance, and will not break. 2.3.3.2 Functionality Function and functionality are very important in the TRIZ context. Functions (benefits) are the things that customers want. TRIZ encourage users to focus on the functional relationship between the different components within and around a system. Typically this is done through an evolved version of the function analysis/value engineering methods originally developed by Miles. The innovation introduced by TRIZ has been the modeling of the negative as well as positive functional relationships in a system. This enables users to define both the problems present in a system and the most appropriate tools to help solve them. By forcing users to examine a system on a component by component basis, the tool enables systematic 15 management of complexity. Latterly, the method has further advanced to better take into account manufacture and assembly process systems. Another important aspect of TRIZ is that it uses function as the principle means of classifying knowledge. Knowledge classification by function enables users to access, for example, all known ways of ‘moving liquids’ or ‘joining surfaces’, etc very rapidly. 2.3.3.3 Resource Maximum effective use of resources is very important in TRIZ. Besides that, we need to think of resources and make use of resources in creative ways. For any product or process, its primary mission is to deliver functions. Because substances and fields are the basic building blocks of functions, they are important resources from TRIZ point of view. However, substances and fields alone are not sufficient to build and deliver functions, the important resources, space and time, are also needed. In the TRIZ point of view, information and knowledge base are also important resources. Resources can be segmented into the following categories. 1. Substance resources: i. Raw material and products ii. Waste iii. By-product iv. System elements v. Substances from surrounding environments vi. Inexpensive substance vii. Harmful substance from the system viii. Altered substance from system 2. Field resources: i. Energy in the system ii. Energy from the environment 16 iii. Energy/field that can be built upon existing energy platforms iv. Energy/field that can be derived from system waste 3. Space resources: i. Empty space ii. Space at interfaces of different systems iii. Space created by vertical arrangement iv. Space created by nesting arrangement v. Space created by rearrangement of existing system elements 4. Time resources: i. Prework period ii. Time slot created by efficient scheduling iii. Time slot created by parallel operation iv. Postwork period 5. Information/knowledge resources: i. Knowledge on all available substances (material properties, transformation, etc.) ii. Knowledge on all available fields (field properties, utilizations, etc.) iii. Past knowledge iv. Other peoples knowledge v. Knowledge on operation 6. Functional resources: i. Unutilized or underutilized existing system main functions ii. Unutilized or underutilized existing system secondary functions iii. Unutilized or underutilized existing system harmful functions 17 2.3.3.4 Contradictions This philosophy can be expressed as either a technical contradiction or physical contradiction. i. Technical contradiction A technical contradiction is a situation in which effects to improve some technical attributes of a system will lead to deterioration of other technical attributes. For example, as a container becomes stronger, it becomes heavier, and faster automobile acceleration reduces fuel efficiency. A technical contradiction is present when The useful action simultaneously causes a harmful action. Introducing (intensification) of the useful action, or elimination or reduction of the harmful action causes deterioration or unacceptable complication of the system or one of its parts. A problem associated with a technical contradiction can be resolved by either finding a trade-off between the contradictory demands or overcoming the contradiction. Trade-off or compromise solutions do not eliminate the technical contradiction but rather soften them, thus retaining the harmful (undesired) action or shortcoming in the system. Analysis of thousands of inventions by Altshuller resulted in formulation of typical technical contradictions such as productivity versus accuracy, reliability versus complexity, and shape versus speed. It was discovered that despite the immense diversity of technological systems and ever greater diversity of inventive problems, there are only about 1250 typical system contradictions. These contradictions can be expressed as a table of contradiction of 39 parameters. (Table 2.2 and Appendix 2A) 18 Table 2.2: Table of 39 parameters of contradiction. 1 2 3 4 5 6 7 8 Weight of movable object Weight of fixed object Length of movable object Length of fixed object Area of movable object Area of fixed object Volume of movable object Volume of fixed object 9 Speed 10 Force 11 Stress, pressure 12 Shape Objects composition 13 stability 14 Strength Duration of moving 15 objects operation Duration of fixed objects 16 operation 17 Temperature 18 Illumination Energy expense of 19 movable object Energy expense of fixed 20 object 21 Power 22 Waste of energy 23 Loss of substance 24 Loss of information 25 Waste of time 26 Quantity of substance Reliability 27 28 Measurement accuracy 29 Manufacturing precision 30 Harmful action at object 31 Harmful effect caused by the object 32 Ease of manufacture 33 Ease of operation 34 Ease of repair 35 Adaption Device complexity 36 37 Measurement or test complexity 38 Degree of automation 39 Productivity From the TRIZ standpoint, overcoming a technical contradiction is very important because both attributes in the contradiction can be improved drastically and system performance will be raised to a whole new level. TRIZ developed many tools for elimination of technical contradiction. One of it is technical contradiction elimination – inventive principles. In this tool, its expressed the contradictions into a matrix of 39 x 39 “engineering parameters’. To resolve these contradictions, 19 Altshuller compiled 40 principles (Table 2.3). Each of these principles contains a few sub-principles, totaling up to 89 sub-principles (Appendix 2B). Table 2.3: Table of 40 inventive principles. 1 2 3 4 5 6 Segmentation Extraction Local Quality Asymmetry Combining Universality 21 22 23 24 25 26 7 Nesting 27 8 Counterweight 28 9 10 11 12 13 14 Prior counter-action Prior action Cushion in advance Equipotentiality Inversion Spheroidality 29 30 31 32 33 34 15 Dynamicity 35 16 17 18 19 20 Partial or overdone action Moving to a new dimension Mechanical vibration Periodic action Continuity of a useful action 36 37 38 39 40 Rushing through Convert harm into benefit Feedback Mediator Self service Copying Inexpensive, short-lived object for expensive, durable one Replacement of a mechanical system Pneumatic or hydraulic construction Flexible membrances or thin film Use of porous material Changing the color Homogeneity Rejecting and regenerating parts Transformation of the physical and chemical state of an object Phase transformation Thermal expansion Use strong oxidizers Inert environment Composite material It should be noted that the 40 principles are formulated in a general way. If, for example, the contradiction table recommends principle 30, “flexible shell and thin films”, the solution of the problem relates somehow to change the degree of flexibility or adaptability of a technical system being modified. The contradiction table and the 40 principles do not offer a direct solution to the problem. It only suggests the most promising directions for searching for a solution. To solve the 20 problem, one has to interpret these suggestions and find a way to apply them to a particular situation. When using the contradiction table and 40 principles, following this simple procedure will be helpful. i. Decide which attribute be improved, and use one of the 39 parameters in the contradiction table to standardize or model this attribute. ii. Answer the following questions: a. How can this attribute be improved using the conventional means? b. Which attribute would be deteriorated if conventional means were used? iii. Select an attribute in the contradiction table. iv. Using the contradiction table, identify the principles in the intersection of the row (attributed improved) and column (attribute deteriorated) for overcoming the technical contradiction. ii. Physical contradiction Usually, contradiction often encounter first as a technical contradiction. However, after digging deeper into the problem, the fundamental cause of the technical contradiction is often a physical contradiction. A physical contradiction is a situation in which a subject or an object has to be in mutually exclusive physical state. A physical contradiction has a typical pattern: “To perform function A1, the element must have property B, but to perform function A2, it must have property –B, or the opposite of P”. In this tool, physical contradiction resolution/separation principles is using. The processes of the principle are as follow. a) Analyze the physical contradiction In order to identify the physical contradiction that causes the technical contradiction, these three steps are recommended to follow in order to preanalyze the conflict: 21 Step 1 Step 2 Step 3 Capture the functions involved in the conflict and established the functional model for the contradiction. Identify the physical contradiction. Identify the zones of conflict. i. Locations properties of conflict. ii. Times properties of conflict. Figure 2.1: Three steps to pre-analyze the conflict. b) Separate the physical contradiction After the identification of the physical contradiction, TRIZ has the following four approaches for resolving the contradiction. They are separation in space, separation in time, separation between components, and separation between components and set of components. i. Separation in space. Separation in space means one part of object has property P, while another part has an opposite property –P. by this separation the physical contradiction can be resolved. In order to accomplish the separation, we need to study the zones of conflict requirements. ii. Separation in time. Separation in time means that at one time period an object has property P, and at another time period it has an opposite property –P. in order to accomplish this, we need to study the time property of the conflict. If it is again a conflict of useful action versus harmful action, we need to identify the periods of both of useful action and the 22 harmful action. We must then identify the time periods when the useful function has to be performed and harmful function eliminated. If we can separate these two periods completely, we may be able to eliminate this contradiction. iii. Separation between the components Separation between the components means that one component has property P, while another component is given an opposite property – P. Sometimes we can limit the number of properties of the component involved in the conflict to one, and we introduce another component to have another property. iv. Separation between components and the set of the components This is an approach that has a set of components made; where every single component must have one property but the whole set of components will have another property. 2.3.3.5 Evolution TRIZ found that the trends of evolution of many technical systems are very similar and predictable. Many technical systems will go through five stages in their evolution processes which are pregnancy, infancy, growth, maturity, and decline. If we put time line in the horizontal axis, and plot; a. Performance b. Level of inventiveness c. Number of inventions d. Profitability 23 Maturity Growth Decline Maturity Growth Decline Infanc y Level of Performanc on the vertical axis, then we will get the four curves shows in Figure 2.2. Infanc y Time Infanc y Profit Number of Decline Maturity Growth Time Decline Maturity Growth Infanc y Time Time Figure 2.2: Curves of technical system evolution (Kai Yang, 2003). 2.3.4 Additional TRIZ Tools The TRIZ methodology can be adapted to different kinds of problem solving. The method described above is relatively simple but forces the user to pre-formulate the problem in terms of standard engineering parameters. It rarely leads to an exhaustive set of solutions. More difficult problems are solved with the following more precise tools. 24 2.3.4.1 ARIZ (Algorithm for Inventive Problem Solving) A systematic procedure for identifying solutions without apparent contradictions. Depending on the nature of the problem, anywhere from five to sixty steps may be involved. From an unclear technical problem, the underlying technical problem can be revealed. Can be used with levels two, three, and four problems. Basic steps include 1. Formulate the problem. 2. Transform the problem into a model. 3. Analyze the model. 4. Resolve physical contradictions. 5. Formulate ideal solution. 2.3.4.2 Su-Field Analysis A tool for expressing function statements in terms of one object acting on another object. The objects are called substances and the action a field. Su-field analysis is helpful in identifying functional failures. By looking at actions as fields, undesirable or insufficient actions can be countered by applying opposing or an intensified fields. 2.3.4.3 Anticipatory Failure Determination (AFD) Prevention of unanticipated failures is important in new product development. AFD, in effect, invents failure mechanisms and then examines the possibilities of 25 their actually occurring. Factors contributing to the failures can be eliminated with this highly pro-active technique. 2.3.4.4 Directed Product Evolution (DPE) Traditional technological forecasting tries to predict the "future characteristics of machines, procedures, or techniques." It relies on surveys, simulations, and trends to create a probabilistic model of future developments. It gives a forecast, but does not invent the technology being forecasted. Altshuller, by studying hundreds of thousands of patents, was able to determine eight patterns of how technological systems develop over time. Based upon the patterns of how people think rather than what people think, DPE is like a road map into the future. Rather than predicting future technologies, one can systematically invent future technologies using DPE. The eight patterns of Directed Product Evolution are given in Table 2.4. Examples will also be shown. Table 2.4: Pattern of evolution of technological systems. Pattern 1. Technology follows a life cycle of birth, growth, maturity, decline. Example Stage 1. A system does not yet exist, but important conditions for its emergence are being developed. Stage 2. A new system appears due to high-level invention, but development is slow. Stage 3. Society recognizes value of the new system. Case Study: Airplane 26 Stage 4. Resources for original system concept end. 1. Manual attempts to fly fail. Stage 5. Next generation of system emerges to replace 2. Wright Brothers fly at original system. 30mph in biplane. Stage 6. Some limited use of 3. Military use in WWI. original system may coexist Financial resources with new system. available. Speeds increase to 100mph. 4. Wood and rope frame aerodynamics reach limit. 5. Metal frame monoplane developed. 6. Several new types of airplanes have been developed but limited use of biplanes still exists. 2. Increasing Ideality. ENIAC computer in 1946 weighed several tons, took a whole room, and did computational functions. In 1995, Toshiba Portégé 610CT weighs 4.5 pounds and is capable of text processing, mathematical calculations, communications, graphics, video, sound. 3. Uneven development of subsystems resulting in contradictions. Subsystems have different life cycle curves. Primitive subsystems hold back development of total system. Common mistake is to focus on improving wrong subsystem. Poor aerodynamics were limitations of early planes but developers focused engine power instead of improving aerodynamics. 4. Increasing dynamism and controllability. Early automobiles were controlled by engine speed. Then manual gearbox, followed by automatic transmissions, and continuously variable transmissions (CVT.) 5. Increasing complexity, followed by simplicity through integration. Stereo music systems have evolved from adding separate components such as speakers, AM/FM radio, cassette player, CD player, etc. to integrated "boom box." 6. Matching and mismatching of parts. 1. Early automobiles used leaf springs to absorb vibration. These were an assembly of unrelated or mismatched parts borrowed from horse carriages 27 and whatever else was available. 2. Later fine tuning allowed adjustments of the parts so that they mated into a matched system - the shock absorber. 3. Purposely mismatch parts to create additional resources from the differences. An example of this might be using a bimetal spring that changed spring rates when a current is applied. 4. Automatic matching and mismatching as needed. For example a computer controlled active suspension system. 7. Transition from macrosystems to microsystems Development of cooking systems from wood burning stove using energy fields to achieve to gas ranges to electric ranges to microwave ovens. better performance or control. 8. Decreasing human involvement with increasing automation. 2.3.5 Development of clothes washing from washboard to washing machine with ringer to automatic washing machine to automatic washing machine with automatic bleach and softener dispensers. Integration TRIZ with Others Problem Solving Tools From survey that done by Zhongsheng Hua, Jie Yang, Solomani Coulibaly and Bin Zhang, TRIZ had been integrated with various method of problem solving tool from years 1995-2005 such as shown in Figure 2.3. The survey showed that TRIZ becomes a value added to the result of the problem that done by the stand alone problem solving tool method. As an example, TRIZ is a useful tool that can solve the problem of ‘how to do’ effectively in the innovative design process, while Quality Function Deployment (QFD) is able to settle the problem of ‘what to do’ (Wang et al., 2005). Another example, the application of Taguchi’s Robust Design makes it 28 possible to optimize the implementation details of the solutions generated by TRIZ and makes the product design specifications insensitive to uncontrolled influences. This integration was explored by references (Verduyn and Wu, 1995; Terninko, 1997; Jugulum and Sefik, 1998; Thimothy, 1998; Novick, 1999; Cavallucci and Lutz, 2000; Schulz et al., 2000; Luke, 2001; Park, 2003; Slocum et al., 2003; Zhao, 2003; Phadke and Smith, 2004). Besides that, the result of survey also shows that TRIZ largely applied with others problem solving tool in the design phases in new product development process where TRIZ solve the contradiction occurred in the early of the design and improvement processes. It seems TRIZ also is needed in order to finalize the decision in selecting concept of the product and also in developing the detail design of product. In others word, application of TRIZ is important to define the conflicts, and then based on the conflicts, to develop innovation solution. VA Global8D 6σ TOC Others NM Method DFMA QFD/FA MindMaps VA AD MBI Brains tormin FME A Robus t NLP KAI Six Hats Figure 2.3: Integration of design problem-solving tools (Zhongsheng Hua, Jie Yang, Solomani Coulibaly and Bin Zhang, 2006). 29 2.4 DESIGN FOR MANUFACTURE AND ASSEMBLY (DFMA) There are several DFMA methods that commonly used which are BoothroydDewhurst method, Lucas Hull method and Hitachi Assembly Evaluation (AEM) method. However, the selected method to be applied in this project is BoothroydDewhurst DFMA method. 2.4.1 What is DFMA? The original definition of DFMA is the integration of manufacturing considerations into the product design process. It is one of the most important tools used by industrial engineers. Its basic objective is to reduce costs and increase efficiency. DFMA also is an approach to improve product performance and to simplify product. DFMA consists of two distinct methodologies: • Design for Assembly (DFA) • Design for Manufacture (DFM) which work together to develop a total product cost by optimizing the design using the best materials and processes to meet customer functions at the lowest possible cost. (G.Boothroyd & P.Dewhurts) 30 2.4.2 The Boothroyd-Dewhurst DFMA Approach With DFMA, significant improvement tends to arise from simplicity thinking, specifically reducing the number of standalone parts. The Boothroyd-Dewhurst DFA methodology gives the following three criteria against which each part must be examined as it is added to the assembly: 1. During operation of the product, does the part move relative to all other parts already assembled? 2. Must the part be a different material than or be isolated form, all other parts already assembled? Only fundamental reasons concerned with material properties are acceptable. 3. Must the part be separate from all other parts already assembled because the necessary assembly or disassembly of other separate parts would otherwise be impossible? A “Yes” answer to any of these questions indicates that the part must be separated or using DFA terminology, a critical part. All parts that are not critical, can theoretically be removed or physically combine with other critical parts. Therefore, theoretically, the number of critical parts is the minimum number of separate parts of the design. Next task is to estimate the assembly time for the design and establish its efficiency rating in terms of assembly difficulty. This task can be done when each part is checked to determine how it will be grasped, oriented, and inserted into the product. From this exercise, the design is rated and from this rating standard time is determined for all operations necessary to assemble the part. The DFA time standard is a classification of design features which affect the assembly process. The total assembly time can then be assessed, and using labor rate, the assembly costs and efficiency can be estimated. At this stage, manufacturing costs are not considered, but assembly time and efficiency provide benchmark for new iterations. 31 An analysis is carried out by using a design for assembly worksheet as shown in Appendix 2C where, the examination of the handling and insertion time of each part is referring to the tables of two-digit manual handling code and two-digit manual insertion code as shown in Appendix 2D and Appendix 2E. After all feasible simplification tasks are introduced, the next step is to analyze the manufacture of the individual parts. The objectives of DFM are to select the most suitable material and manufacturing process. Boothroyd-Dewhurst DFMA methodology uses compatibility matrix for the processes and materials selection as shown in Appendix 2F. In the selection of appropriate processes, the process capabilities to manufacture a particular part shape are based upon the shape attributes of the part. The attributes of the part are determined by the part geometric itself. There are eight general shape attributes that need to be clearly understood during applying the materials and processes selection. The shape attributes are: 1. Depressions (Depress) - The ability to form recesses or grooves in the surfaces of the part. 2. Uniform Wall (UniWall) - Uniform wall thickness. 3. Uniform Cross Section (UniSect) - Parts where any cross sections normal to a part axis are identical, excluding draft. 4. Axis of Rotation (AxisRot) - Parts whose shape can be generated by rotation about a single axis: a solid of revolution. 5. Regular Cross Section (ResXSec) - Cross sections normal to the part’s axis contain a regular pattern. 6. Captured Cavities (CaptCav) - The ability to form cavities with reentrant surface. 7. Enclosed (Enclosed) - Parts which are hollow and completely enclosed. 32 8. Draft Free Surface (NoDraft) - The capability of producing constant cross sections in the direction of tooling. Table of the shape generation capabilities for various processes are shown in Appendix 2G. By referring to the table, the shape attributes with a “Yes” will eliminate those processes that are not capable of producing these features. While, those features with a “No” will eliminate those processes that are only capable of producing part with these features present. 2.5 Summary Value engineering has been successfully applied to the new product development as the use of VE in NPD can provide high value products and services to customers while simultaneously providing profits to the manufacturers and suppliers. Besides that, TRIZ approach is a problem solving tool that had showed a good result as it been integrated with various others problem solving tool which is help them to solve contradiction problem. TRIZ is a logical, knowledge-based methodology for early stages of the design process. Guided by TRIZ, users not only overcome the psychological barrier but they also have the opportunity to analyze the best direction for improvement of product. CHAPTER 3 TRIZ – PROBLEM SOLVING PROCEDURE 3.1 Introduction This chapter will explain about the tool that has been selected for the analysis in this project which is Technical Contradiction Elimination – Inventive Principle method. Technical Contradiction Elimination – Inventive Principle is one of the several problem solving methods proposed by the TRIZ. The other methods are Physical Contradiction Resolution/Separation Principle, Functional Improvement Methods/TRIZ Standard Solutions, Complexity Reduction/Trimming, Evolution of Technological Systems, and Physical, chemical and geometric effect based. Before details about selected tool step by step process is explained, this chapter first shows the general TRIZ process procedure. 34 3.2 General TRIZ Process Procedures TRIZ has a four-step problem solving processes as shown in Figure 3.1. In this process procedure, step two is where the problem solving tool, Technical Contradiction Elimination – Inventive Principle method for this Master project is selected. Problem definition Problem Classification & Problem Tool Selection Problem Solution Solution Generation Figure 3.1: Four steps of TRIZ process procedure. 3.2.1 Problem definition Problem definition is a very important step. The quality of the solution is highly dependent on problem definition. The problem definitions start with several general questions: 35 1. What is the problem? 2. What is the scope of the project? 3. What subsystem, system, and components are involved? 4. Do we have a current solution, and why is the current solution not good? These are common questions to be asked in any engineering project. By answering these questions, we are able to define the scope of the project and focus on the right problem area. Besides answer these common questions, several TRIZ methods are also very helpful in the problem definition stage. i. Functional modeling and functional analysis. After identifying the project scope, it is very helpful to establish the functional model of the subsystem involved in this project. Functional modeling and analysis enables us to see the problem more clearly and precisely. Subject Action Object or Field ii. Ideality and ideal final result After functional modeling and functional analysis, we can evaluate the ideality of the current system by using Ideality = ∑ benefit / ∑ costs + ∑ harm Ideal final result means the ultimate optimal solution for current system in which; ∑ benefits → ∞ and ∑ costs + ∑ harm → 0 By comparing the ideality of the current system with idea final result, we can identify “where the system improvement should go” and “what aspects of system should be 36 improved”. This will definitely help the problem definition and identify “what problem should be solved”. iii. S-curve analysis. It is very beneficial to evaluate the evolution stage of the current technical system involved in any TRIZ project. For example, if our current subsystem is at growth stage, then we should focus our attention to gradual improvement. If our subsystem is near the maturity stage, then we will know that it is time to develop the next generation of this subsystem. iv. Contradiction analysis By using the method described in chapter 2, we can determine if there are any physical contradictions or technical contradictions in our current system. TRIZ has many methods to resolve contradictions. 3.2.2 Problem Classification and Tool Selection In this step, problem solving tool will be selected regarding to the problem definition that had been identify. After we are finished with the problem definition, we should able to classify the problem into the following categories. For each category there are many TRIZ methods available to resolve the problem. i. Physical contradiction Method : Physical contradiction resolution and separation principles. ii. Technical contradiction Method : Inventive principles. 37 iii. Imperfect functional structures This problem occurs when there are inadequate useful functions or lack of needed useful functions and when there are excessive harmful functions. Method : Functional improvement methods and TRIZ standard solutions. iv. Excessive complexity This problem occurs when the system is too complex and costly, and some of its functions can be eliminated or combined. Method : Trimming and pruning. v. System improvement This problem occurs when the current system is doing its job, but enhancement is needed to beat the competition. Method : Evolution of technological systems. vi. Develop useful functions This problem occurs when we can identify what useful functions are needed to improve the system but we do not know how to create these functions. Method : Physical, chemical, and geometric effect database. 3.2.3 Solution Generation There are usually many TRIZ methods available for solving the problems after problem classification. So many alternative solutions could be found. These solutions will be evaluated in the next step. 38 3.2.4 Concept Evaluation In this step, concept evaluation methods such as Pugh concept selection, value engineering, and the axiomatic design method can be used to evaluate and select the best solution. 3.2.5 TRIZ tool selection From the view and research of the TRIZ tool to solve the problem in designing product, the Technical Contradiction Elimination – Inventive Principle method is selected. This is because this tool makes a decision based on the deleting the contradiction occurred by considering the parameter that may affect and principles that had to change in order to solve that problem. 3.3 Technical Contradiction Elimination – Inventive Principle Method Figure 3.2 shows the four steps in applying this tool to solve problem in designing the product for improvement. The first step is defined what are the problems that occurred. After the problem had identified, the second step is to formulate the problem. Then search for the previously well-solved problem and lastly looks for analogous solution and adapt to the solution. In order to show how this tool will be applied in this project, simple example will be used in this chapter which is beverage can. 39 Figure 3.2: Technical Contradiction Elimina Elimination – Inventive Principle step-by-step. step 3.3.1 Step 1 – Identify the Problem Boris Zlotin and Alla Zusman, principles TRIZ scientists at the American company Ideation and students of Altshuller have developed an "Innovative Situation Questionnaire" to identify the engineering system being studied, its operating environment, resource ce requirements, primary useful funct function, ion, harmful effects, and ideal results. Table 3.1 show shows the characteristic of the beverage can requirement for improvement. 40 Table 3.1: Table characteristic of beverage can through Innovative Situation Questionnaire. Characteristic Engineering system To contain beverage Operating environment Cans are stacked for storage purpose Resources requirement Primary useful function Harmful effect Ideal result 3.3.2 What the thing i. ii. iii. Internal pressure of van Weight of filled can Rigidity of can construction To contain beverage i. ii. Cost of material and process Waste of storage space Can that can support the weight of stacking to human weight without damage to can. Formulate the Problem Restate the problem in terms of physical contradictions. Identify problems that could occur. Could improving one technical characteristic to solve a problem cause other technical characteristics to worsen, resulting in secondary problems arising? Are there technical conflicts that might force a trade-off? In the case of beverage can, we cannot control the height to which cans will be stacked. The price of raw materials compels us to lower costs. The can walls must be made thinner to 41 reduce costs, but if we make the walls thinner, it cannot support as large a stacking load. Thus, the can wall needs to be thinner to lower material cost and thicker to support stacking-load weight. This is a physical contradiction. If we can solve this, we will achieve an ideal engineering system. 3.3.3 Previously Well-Solved Problem Altshuller extracted from over 1,500,000 world-wide patents these 39 standard technical characteristics that cause conflict. These are called the 39 Engineering Parameters. Find the contradicting engineering principles. First find the principle that needs to be changed. Then find the principle that is an undesirable secondary effect. State the standard technical conflict. In beverage can problem, the standard engineering parameter that has to be changed to make the can wall thinner is "#4, length of a nonmoving object." In TRIZ, these standard engineering principles can be quite general. Here, "length" can refer to any linear dimension such as length, width, height, diameter, etc. If we make the can wall thinner, stacking-load weight will decrease. The standard engineering parameter that is in conflict is "#11, stress." The standard technical conflict is: the more we improve the standard engineering parameter "length of a nonmoving object," the more the standard engineering parameter "stress" becomes worse. 3.3.4 Look for Analogous Solutions & Adapt To the Solution Altshuller also extracted from the world wide patents 40 inventive principles. These are hints that will help an engineer find a highly inventive (and patentable) 42 solution to the problem. Examples from patents are also suggested with these 40 inventive principles. To find which inventive principles to use, Altshuller created the Table of Contradictions (Appendix 2A). The Table of Contradictions lists the 39 Engineering Parameters on the X-axis (undesired secondary effect) and Y-axis (feature to improve). In the intersecting cells, are listed the appropriate Inventive Principles to use for a solution. The engineering parameters in conflict for the beverage can are "#4, length of a nonmoving object" and "#11, stress." The feature to improve (Y-axis) is the can wall thickness or "#4, length of a nonmoving object" and the undesirable secondary effect (X-axis) is loss of load bearing capacity or "#11, stress." Looking these up on the Table of Contradictions, we find the numbers 1, 14, and 35 in the intersecting cell. 2 Weight of fixed object 3 Length of movable object 4 Length of fixed object 5 Area of movable object 10 1 29 35 8 15 29 34 2 17 29 4 35 30 13 2 7 17 4 35 13 4 8 35 8 2 14 7 14 17 4 29 30 4 34 8 10 18 37 8 10 19 35 17 10 4 28 10 10 36 47 40 13 29 10 18 1 8 35 1 14 35 10 15 36 28 19 30 35 2 Figure 3.3: Result for the problem. The inventive that should be considered are in the red highlight numbers (Kai Yang and Basem, H. M.,2003). Stress, pressure Force Speed 28 15 38 5 35 14 2 17 7 4 35 14 15 18 4 9 Volume of fixed object 8 29 2 40 28 15 17 4 35 28 40 29 Volume of movable object Area of fixed object 6 29 17 38 34 7 Area of movable object Length of fixed object 4 5 Length of movable object 3 Weight of fixed object 2 15 8 29 34 11 Weight of movable object 10 1 Weight of movable object What should improved? 1 What is deteriorated? 43 Below are the details about the inventive principle which is what we have to do. i. Inventive Principle 1 is Segmentation a. Divide an object into independent parts b. Make an object sectional c. Increase the degree of an object's segmentation So that, for the beverage can cases, using Inventive Principle 1 c. "Increase the degree of an object's segmentation," the wall of the can could be changed from one smooth continuous wall to a corrugated or wavy surface made up of many "little walls." This would increase the edge strength of the wall yet allow a thinner material to be used. See Figure 3.4. Figure 3.4: Cross section of corrugated can wall (Wikipedia-TRIZ, 2009). ii. Inventive Principle 14 is Spheroidality a. Replace linear parts or flat surfaces with curved ones; replace cubical shapes with spherical shapes b. Use rollers, balls spirals 44 c. Replace a linear motion with rotating movement; utilize a centrifugal force Using Inventive Principle 14 a., the perpendicular angle at which most can lids are welded to the can wall can be changed to a curve. See Figure 3.5. Figure 3.5. Spheroidality Strengthens Can's Load Bearing Capacity. Perpendicular angle has been replaced with a curve (Wikipedia-TRIZ, 2009). . iii. Inventive Principle 35 is Transformation of the physical and chemical states of an object. a. Change an object's aggregate state, density distribution, degree of flexibility, temperature For beverage can case, we change the composition to a stronger metal alloy used for the can wall to increase the load bearing capacity. 45 3.4 Summary The inventive principle is the factors or things that we can refer it to do the improvement and in the same time solve the problem occurred. As a conclusion, the steps showed in this chapter will be used as a tool of this thesis case study. It will be applied to the selected product case study together with the DFMA Methodology. CHAPTER 4 PRODUCT CASE STUDY 4.1 Introduction One of the “Product Design Improvement through VE and DFMA Methodology” objectives is to select a consumer product as a case study. So that, “Sponge Mop” had been chosen for this case study as illustrated in Figure 4.1. In this Chapter 4, the product information, product assembly sequences, and function of each part of the selected product will be shown. 47 4.2 Product as a Case Study Technology has improved our everyday life vastly. It's changed so much from how people lived just 50 years ago that it would be impossible to explain to someone 50 years ago what life is like today. Even, a simple product like mop also had been through the several improvement stages until there are many types of mop, where they are more easy to use now. Sponge mop is a cleaner device that basically used to clean dirt on floor. There are two types of mop which are wet or dry mop. However, in this case study, sponge mop which is classified under wet mop is used as a subject to be studied. 4.2.1 Product Selection The Sponge Mop chosen is the latest design of the mop in the market. It is widely used by the household and also by the people that involve in cleaning job. This sponge mop consists of fully mechanical part which creating a motion of the wiper through the movement of handle that led others movement of part such a pusher, arms and wiper holders. This sponge mop also has a sponge that can be put in water with a detergent or other cleaner (under the general term surfactant) and rinsed when cleaning is finished. Its head can be easily cleaned themselves and replaceable when they begin to wear. There are several steps to use the sponge mop which are: i. The wiper is put into a water to make the wiper mild. Without water, wiper can’t be squeeze because the material of wiper (sponge) will become hard if it is dry. ii. Squeeze the wiper to remove the water by pulling the handle. iii. Start the cleaning process and squeeze the wiper when necessary. 48 The sponge mop that has been used in this case study is shown in Figure 4.1. Figure 4.1: Sponge Mop. 4.2.2 Product Tree Structure Product tree structure will show us the level of assembly for the product where the number of level will determine the efficiency of the product assembly. In order to minimize product assemble time, the number of level should be less. The product tree structure for the sponge mop is shown in the Figure 4.2 which indicates three levels of assembly. Pin B (2) (4) (1) Legends: Level 0 Level 2 Level 1 (1) Handle Bracket (1) Ring (1) Stopper Figure 4.2: Sponge Mop product tree structure. (2) (2) Screw B (1) Nut (1) (1) Handle Lock Handle (1) Pusher L Pusher R Pusher Nut (1) Pin A (1) Screw A (2) (2) Joint (1) Wiper Arm Connector Wiper Holder Head Sponge Mop (1) Female Adjuster (1) Male Adjuster Rod (1) Rod A (1) Rod B 49 (1) Knob 50 4.2.3 Part ID Number Each part of the sponge mop is assigned with an ID number presented by assembly sequences. The sponge mop consists of 30 parts of total number of part and 21 parts different number of part. Table 4.1 illustrates the sponge mop part ID number. Table 4.1: The Sponge Mop part ID number. Part ID Part Name Quantity 1 Connector 1 2 Screw A 1 3 Arm 2 4 Pin A 4 5 Wiper Holder 2 6 Joint 1 7 Pin B 2 8 Wiper 1 9 Rod A 1 10 Rod B 1 11 Male Adjuster 1 12 Female Adjuster 1 13 Stopper 1 14 Ring 1 15 Knob 1 16 Handle Bracket 1 17 Lock Handle 1 18 Screw B 2 19 Pusher R 1 20 Pusher L 1 21 Nut 3 Total part 30 51 4.2.4 Assembly Sequence Assembly sequence is a sequence of the parts being assembled to become a functional product. In this case, total of 30 parts being assembled to become one functional sponge mop. Determination of the sequence is the early process that should take into accounts. This is because from the assembly sequence, the difficulty in the assembly process of the part can be defined. The assembly sequence of the sponge mop is shown in Appendix 4. 4.3 Part Critique The original part design of this sponge mop has their self function, strength and weaknesses. Therefore, this part indicates about the each part of sponge mop function, strength and weaknesses in an assembly point of view. Table 4.2 shows the part critique for each part of sponge mop product. 52 Table 4.2: Part critique of each part for Sponge Mop Part ID Picture Part Name Function - To connect the Head and Rod. - To hold the arms. 1 2 Remark - Assembly time higher because of fastening part using screw. - Part not symmetry, increasing handling and insertion time. Connector - To tighten the part. - Require longer time to fasten part. - As a movement part for the wiper holder. - Provide squeeze operation for the wiper. Screw A - Require holding down, not self located. 3 Arm - Part not symmetry, increasing handling and insertion time. - To joint between two parts. 4 Pin A - Part is symmetry, lower handling and insertion time. - High assembly time regarding to the fit tolerance between pin and part to joint. 53 Table 4.2: Continued Part ID Picture Part Name Function - To hold the wiper. 5 Remark - Part not symmetry, increasing handling and insertion time. Wiper Holder - Require holding down, part not self located. 6 7 - As a joint device for two wiper holders. - Part not symmetry, increasing handling and insertion time. - To joint between two parts. - Part is symmetry, lower handling and insertion time. Joint Pin B - High assembly time regarding to the fit tolerance between pin and part to joint. - To absorb water for cleaning purpose. 8 - Easy to dry because the material used is polyurethane foam. Wiper - To locate knob, ring and stopper. 9 Rod A - Easy to absorb water. - To hold the mop during clean operation. - Very light material. 54 Table 4.2: Continued Part ID 10 11 12 13 Picture Part Name Rod B Function - To locate Handle sub assembly, male adjuster and female adjuster. - Very light material. - To adjust the length of the rod. - Higher assembly time regarding to the thread mechanism when to fasten or loosen the part. - To adjust the length of the rod. - Higher assembly time regarding to the thread mechanism when to fasten or loosen the part. - To stop the last position of Rod A. - Make by harden material and not providing cushion. Male Adjuster Female Adjuster Stopper Remark - Part not symmetry. - Part not symmetry. 14 Ring - As a cushion to the Stopper. - Part not symmetry. - Separate assembly. 15 Knob - As a gripping purpose when handling the product. - Very comfort to grip. 55 Table 4.2: Continued Part ID 16 Picture Part Name Handle Bracket 17 Lock Handle Function - To locate the Lock Handle. - The part is not necessary as the Handle can directly assemble with Rod B. - To push and pull Pusher for squeezing the wiper to remove water. - Good design because provide locking device. 18 Screw B - To tighten the part. 19 Pusher R - To push and pull Head subassembly. (right) Remark - Comfortable to handle. - Require longer time to fasten part. - Good in pulling and pushing (very strong). 20 Pusher L (left) - To push and pull Head subassembly. 21 Nut - To tighten the part. - Bad design because using more than one pusher. - Higher time in assembly because of treading mechanism. - Part is not symmetry. 56 4.4 Summary Sponge Mop had been chosen because it is a fully mechanical product which is overall of its part can be easily disassembled and determined by using manual DFA analysis. The process of disassemble had been done to determine the sequence of product assembly process. Besides that, the function of each part also been determined by the disassemble process. The total number of parts of sponge mop is 30 parts while the total number of different parts is 21 parts. CHAPTER 5 DESIGN FOR ASSEMBLY (DFA) ANALYSIS FOR ORIGINAL DESIGN 5.1 Introduction This chapter discusses about the analysis result of the original design of sponge mop that done by using Boothroyd Dewhurst DFMA approach. The discussion will look into classification of each part for manual handling and insertion, DFA worksheet analysis, estimated assembly time and cost, and also design efficiency of the original design of sponge mop. 58 5.2 Classification of Product Parts This section describes about the alpha (α) and beta (β) symmetry value for each part of the sponge mop. Value of alpha and beta then will determine the two digit manual handling and insertion code of each part. Determination of the two digit code indicates the handling and insertion time for each part that which be used to determine the operation time and cost of the product. Table 5.1 shows the analysis of classification of product part for the original design. Table 5.1: Classification of Part for Original Design Part Manual Handling Manual Manual Alpha (α) Beta (β) Handling Code Insertion Code 1.Connector 360º 180º 20 08 2.Screw A 360º 0º 10 38 3.Arm 180º 180º 10 08 4.Pin A 180º 0º 00 31 5.Wiper Holder 360º 360º 30 06 6.Joint 360º 180º 20 06 7.Pin B 180º 0º 00 31 8.Wiper 360º 180º 20 31 9.Rod A 360º 180º 20 00 10.Rod B 360º 0º 10 38 11.Male Adjuster 360º 0º 10 38 12.Female Adjuster 360º 0º 10 38 13.Stopper 180º 0º 10 32 14.Ring 360º 360º 30 30 15.Knob 360º 180º 20 30 16.Handle Bracket 360º 360º 30 30 17.Handle 360º 360º 30 06 18.Screw B 360º 0º 10 38 59 Table 5.1: Continued Part Manual Handling Manual Manual Alpha (α) Beta (β) Handling Code Insertion Code 19.Pusher R 360º 360º 30 31 20.Pusher L 360º 360º 30 31 21.Nut 360º 0º 10 38 5.3 Theoretical Minimum Part Assessment The assessment of theoretical minimum part discusses the implementation of the DFA principles by using the Q&A (question and answer) format for each part. The assessments then will determine the value of the theoretical minimum number of part, Nm. The value zero, 0 and one, 1 playing a vital role in consideration of redesigning part. Besides being redesigned, the elimination of the part may be occurred if the parts were not essential. The theoretical minimum part assessment questions asked are as stated below: i) Does this part move relative to another? ii) Do the mating parts have to be making of different materials? iii) Do the parts have to be separate to allow servicing before or after assembly? 60 5.4 DFA Worksheet DFA worksheet will show the result of the analysis of the product, sponge mop. In this section, the analysis is done for the original design of the sponge mop. Table 5.2: DFA worksheet analysis for original design. Estimation of theoretical minimum # of parts, 0 or 1 9 Operation cost, cents, 0.1042 x (7) 8 Operation time, sec, (2) x [(4) + (6)] 7 Manual insertion time per part 6 Two-digit manual insertion code 5 Manual handling time per part 4 Two-digit manual handling code 3 # of times the operation is carried out consecutively 2 Part ID # 1 Name of Part 0 Connector 1 1 20 1.8 08 6.5 8.3 0.86486 1 Screw A 2 2 10 1.5 38 6 15 1.563 0 Arm 3 2 10 1.5 08 6.5 16 1.6672 2 Pin A 4 2 00 1.13 31 5 12.26 1.277492 0 Wiper 5 2 30 1.95 06 5.5 14.9 1.55258 2 Joint 6 1 20 1.8 06 5.5 7.3 0.76066 1 Pin B 7 4 00 1.13 31 5 24.52 2.554984 0 Wiper 8 1 20 1.8 31 5 6.8 0.70856 1 Rod A 9 1 20 1.8 00 1.5 3.3 0.34386 1 Rod B 10 1 10 1.5 38 1.5 3 0.3126 1 Male 11 1 10 1.5 38 6 7.5 0.7815 1 Holder Adjuster 61 Table 5.2: Continued. Estimation of theoretical minimum # of parts, 0 or 1 9 Operation cost, cents, 0.1042 x (7) 8 Operation time, sec, (2) x [(4) + (7)] 7 Manual insertion time per part 6 Two-digit manual insertion code 5 Manual handling time per part 4 Two-digit manual handling code 3 # of times the operation is carried out consecutively 2 Part ID # 1 Name of Part 0 Female 12 1 10 1.5 38 6 7.5 0.7815 1 Stopper 13 1 10 1.5 32 4 5.5 0.5731 1 Ring 14 1 30 1.95 30 2 3.95 0.41159 0 Knob 15 1 20 1.8 30 2 3.8 0.39596 1 Handle 16 1 30 1.95 30 5 6.95 0.72419 0 Handle 17 1 30 1.95 06 5.5 7.45 0.77629 1 Screw B 18 1 10 1.5 38 6 7.5 0.7815 0 Pusher R 19 1 30 1.95 31 5 6.95 0.72419 1 Pusher L 20 1 30 1.95 31 5 6.95 0.72419 0 Nut 21 3 10 1.5 38 6 22.5 2.3445 0 194.93 20.3117 15 TM CM NM Adjuster Bracket Total 62 5.5 Results From the DFA worksheet analysis, the results of the estimated time, cost and design efficiency of the assembly are obtained. Below are the summary of the result for the original design analysis. Total assembly time, TM = 194.93 secs. Total assembly cost, CM = 20.3117 cents. Theoretical minimum number of part, NM = 15 Design efficiency, DE = 23.09% Note: 1) The value of total assembly cost (CM) is gained from the calculation below: Value of labor cost per second (n) may vary due to different assumption and for this case study, below n assumption is used. - Monthly salary for one operator = RM 600 - Number of working day = 20 days/month - Number of working hour/day = 8 hours/day So, labor cost per second, n = RM 600 / (20 days x 8 hours x 3600secs) = RM 0.001042/sec = 0.1042 cents/sec Thus, CM = TM x n = 194.93 secs x 0.1042 cents/sec = 20.3117 cents. 63 2) The design efficiency of the original design is gained by using below formula; DE = 3 x NM x 100% TM = (3 x 15/ 194.93s) x 100% = 0.2309 x 100% = 23.09% 5.6 Summary The analysis result of the original sponge mop had been showed through the DFA worksheet analysis. From the design efficiency result, the product needs to be improved because the value was categorized in less efficient. The design improvements of the product Sponge Mop will be done based on analysis through minimize the theoretical minimum number of parts and total assembly time. CHAPTER 6 PROPOSED IMPROVEMENT OF NEW DESIGN USING DFMA METHODOLOGY AND TRIZ CONCEPT 6.1 Introduction This chapter discusses the proposed design improvement of the Sponge Mop. There are two sections which are design improvement by using DFMA methodology and design improvement using TRIZ concept. The detail of improvement also will show in this chapter. 65 6.2 Improvement by Using DFMA Methodology. Design improvement of product through DFMA Methodology is based on the analysis of the important of part itself, part symmetry, difficulty in handling and also difficulty in insertion of the part in assembly process. 6.2.1 Improvement 1: Connector Figure 6.1 shows the original and new design of connector. There are four features that had been improved to minimize the handling and insertion time. This new connector is designed with sliding track that will guide the motion of the wiper holders when wiper is squeezed inside. The sliding track will improve the motion of wiper holders, and consequently eliminating the function of arms and pins. Flat end features is designed to provide support and rigidity of wiper when consumers are using this sponge mop. If it’s designed to be round or others shape that not flat, wiper holder will freely moving and that will cause difficulties as the wiper holders are not stacked during consumers used the sponge mop. Although handle is provided to locking the wiper holders to its position, this flat end features will support the function. Round features are designed to ease the motion of wiper holders when wiper is squeezed. If these features are not provided, the motion of wiper holders will stack and wiper cannot be squeezed. Locking hole is used together with snap fit shaft to lock the connector with Rod A. This locking hole is designed slightly bigger that the original sponge mop to locking the mating part rigidly. This improvement had decrease the assembly time about 4.5 seconds. As showed in Chapter 5, assembly time for original design connector is 8.3 seconds while for this new design, the assembly time is only 3.8 seconds. 66 Original Design New Design Flat End Round Features Locking Hole Locking Hole Sliding Track Figure 6.1: Design improvement of connector. 6.2.2 Improvement 2: Wiper Holder Figure 6.2 shows the original and new design of wiper holder. There are two features that had been designed which are locking hole and slider. In original design of sponge mop, the wiper holders was designed to be hold due to the parts is not secured during assembly operation until pins were fixed to the hole. New design had been made with concern to that problem. Thus new design is introduced to overcome the problem. Now, locking hole is used together with ball plunger that had been merged together with joint. Ball plunger is a standard part that can be easily got in market. In new design, parts are assembled to joint without the part required to hold down. Assembly time by using this method is significantly reduced. Slider feature is used to eliminate the function of pins in the original design and ensure the motion of wiper holders is smooth. This improvement had decreased the assembly time about 19.26 seconds. 67 Original Design New Design Slider Locking Hole Pin Hole Figure 6.2: Design improvement of wiper holder. 6.2.3 Improvement 3: Male Adjuster Figure 6.3 is illustrating the new design of male adjuster. The new male adjuster had been modified from the original design which switching the screwing method to the snap fit features. This part is cannot be eliminated because it is essential, thus modification to ease the insertion process is made. This mechanism is similar to the mechanism that used on helmet at the locking device. By using this method time for insertion is reduced. This improvement had decreased the assembly time about 3.7 seconds. As showed in Chapter 5, assembly time for original design male adjuster is 7.5 seconds while for this new design, the assembly time is only 3.8 seconds. 68 Original Design New Design Thread Snap Fit Figure 6.3: Design improvement of Male Adjuster. 6.2.4 Improvement 4: Female Adjuster Figure 5.5 shows the new design of female adjuster for sponge mop. Two important features had been introduced which are snap fit feature and tapered feature. This feature is very important in reducing assembly time and improving quality of product. Snap fit method is used to simplify the assembly operation and also to reduce the fastening time. It is because, in original design, method used is same as screwing process. For tapered features, it was design to make a male adjuster tightly gripping the Rod B. This improvement had decreased the assembly time about 3.7 seconds. As showed in Chapter 5, assembly time for original design female adjuster is 7.5 seconds while for this new design, the assembly time is only 3.8 seconds. 69 Original Design New Design Snap Fit Tapered Figure 6.4: Design improvement of female adjuster. 6.2.5 Improvement 5: Stopper Stopper is one of the important parts in sponge mop such indicated in Figure 6.5. Before this, stopper is used together with ring to provide limit of rod movement and act as a cushion. This separate part will increase the time of assembly. Therefore, ring is merged into stopper by designing stopper that will provide cushion function. Material is uses as the material of stopper. The combination of ring and stopper had decreasing assembly time of these parts about 2.2 seconds. In the original design, assembly of these parts is 6 seconds while it only taking 3.8 seconds in the new design assembly process. 70 Original Design Stopper New Design Ring Figure 6.5: Design improvement of Stopper. 6.2.6 Improvement 6: Rod A Design of Rod A in a new design has a little bit different compare to the original design. One feature had been added to the Rod A which is slot. Slot feature is added to make the insertion of the stopper is easy because the assembly method between Rod A and stopper had been changed to ease the assembly operation. In new design, stopper is inserting to the Rod A without orientation by adding the slot feature. Figure 6.6 is showing the Rod A of new design. Original Design New Design Slot Figure 6.6: Design improvement of Rod A. 71 6.2.7 Improvement 7: Handle Figure 6.7 shows the handle design of new sponge mop. Generally, it shapes is same to the original design. But one feature is added in order to simplify the assembly method of sponge mop. The feature is slot. This slot is added because in the new design, only one pusher is used and that pusher must be pivoted center to the handle. The assembly time of the new design resulted same value with the original design which is 7.45 seconds. It means the two digits code for manual handling and insertion remains constant. Original Design New Design Slot Figure 6.7: Design improvement of Handle. 6.2.8 Improvement 8: Joint Figure 6.8 illustrates the new design of joint. In new design, three parts are combined into one part which is two pins and joint. This new method is using ball plunger which the ball plunger is a standard part. This improvement is dramatically 72 reduced the assembly operation because before this, joint is connected to others parts using pins. This improvement had decrease the assembly time about 3.5 seconds. As showed in Chapter 5, assembly time for original joint is 7.3 seconds while for this new design, the assembly time is only 3.8 seconds. Original Design New Design Ball Plunger Figure 6.8: Design improvement of Joint. 6.2.9 Improvement 9: Snap Fit Shaft Figure 6.9 shows the new fastener that replacing the screws and nuts. Assembly time using this snap fit is reduced. This method is not affecting the function of sponge mop because before this the function of screws is like a shaft that allowing motion of other parts. Through this method, nuts is eliminated because the operator just need to push this snap fit into hole position which the end features is acting as a nut to prevent the shaft from dismantle. 73 Figure 6.9: New part design of Snap Fit Shaft. 6.2.10 Improvement 10: Pusher In new design, only one pusher is used to push and pull the handle. Design changes were in terms of size of the pusher and also its shape such indicated in Figure 6.10. By using this pusher, time to assembly will dramatically reduced as it no more using screws in its assembly. The elimination of one pusher had reducing the time of assembly operation about 9.95 seconds. In original design, time required is about 13.9 seconds while in the new design the assembly time taken is about 3.95 seconds. Figure 6.10: Improvement of Pusher quantity from two into one. 74 6.3 Improvement by Using TRIZ Concept Design improvement through TRIZ concept is based on the solution that given by the TRIZ itself. The solution is resulted from the contradiction problem occurred during the improvement process by referring to the contradiction table of inventive principles [Appendix 3]. 6.3.1 Improvement 1: Pusher Figure 6.11 shows the new design of Pusher after consideration with using TRIZ concept. The problem with the old design of pusher sponge mop is it has two pushers to pull the sponge mop wiper. Even though the performance is good however it influences the rate of time and cost assembly of the part. So, in order to reduce the time and cost of assembly, the used of only one pusher from two pushers is proposed. Below is the TRIZ concept consideration to the problem occurred. Improving parameter: Shape (Parameter 12) Worsening parameter: Strength (Parameter 14) Solutions : Principles 30, 14, 10 and 40 From the four principles suggested by the TRIZ solution, the principle 40 is the suitable element in improving the part. Principle 40 proposed a solution about to make the part from composite material. Composite material will hardened the strength of the part evens the shape of part designed look like not giving enough performance. So, the pusher has been designed like Figure 6.11, where the combination of two pushers had eliminated one pusher of the Sponge Mop product. 75 Figure 6.11: New design of Pusher by combining two pushers into one. 6.3.2 Improvement 2: Male and Female Adjuster Tread mechanism is known as the longest taking time in assembly process. However, it also known as the mechanism for ease of maintenance as people will easily open and close it. In this case, the elimination of the tread mechanism will reduce the time taken to assembly the part. If in others improvement design tools, the consideration of the effect of the improvement is overlook. But using TRIZ concept, the effect that will occur during the improvement is measured. In this case, the strength of the two part mate together will be less. Improving parameter: Ease of operation (Parameter 33) Worsening parameter: Strength (Parameter 14) Solutions: Principles 32, 40, 3 and 28 The result from the TRIZ analysis shows that elements in Principle 32 and 40 can be used to improve the male and female adjuster. One of the elements in Principle 32 state that the problem can be solved by change the degree of translucency of an object or processes which are difficult to see. In this part case study, the used of transparency color of material will make the part ease of operation as it enable operator to assemble it without intervention. Then, the Principle 40 will solve the 76 problem occur because of improvement parameter which is strength. Combination of material or composite material makes the part more reliable then the part produce using single material. Figure 6.12 shows the improvement of the Male and Female Adjuster. Lock Slot Lock Leaf (a) (b) Figure 6.12: (a) New design of male adjuster with lock leaf, and (b) New design of female adjuster with lock slot. 6.3.3 Improvement 3: Joint After several operation of the product, one of the parts which are pusher started to damage the joint regarding the force given into it by the pusher. In order to reduce the harmful effect caused by the pusher into joint, it required less force during the operation. However, to maximize the product functionality, the high force is required. Improving parameter: Harmful action at object (Parameter 30) Worsening parameter: Force (Parameter 10) 77 Solutions: Principles 13, 35, 39 and 18 The result from the TRIZ analysis shows that elements in Principle 13 and 35 can be used to reduce the harmful action at parts joint. One of the elements in Principle 13 is invert the action used to solve the problem and in Principle 35 is change the degree of flexibility. In this case, the idea is instead of using different material between two objects (pusher and joint), change the joint material and increase the flexibility of the joint into the same value flexibility of pusher. The original joint is produce by using plastic material. So that, joint produced by using the steel material same as the pusher is proposed. 6.3.4 Improvement 4: Wiper Holder, Connector, Arm and Pin ` During the assembly process of the Sponge Mop, some of the parts look like repeating the job that be done by other parts. It can be saw by the assemble parts between wiper holder, pin, arm and connector. In this case, arm is not necessary as the wiper holder still can be functioning without part of arm. However, in order to reduce number of part in head area, the maintenance of the head area may more difficult. Improving parameter: Device complexity (Parameter 36) Worsening parameter: Ease of repair (Parameter 34) Solutions: Principles 1 and 13 The result from the TRIZ analysis shows that elements in Principle 1 and 13 can be used to reduce the ease of repair problem. In this case, the combination of one element from each principle is be used to solve this problem. The element in Principle 1 is make an object easy to disassemble while element in Principle 13 is invert the action used to solve the problem. So, its means instead of using arm to function the wiper holder, make the wiper holder function by its own. A new wiper 78 holder is functioning direct through the connector. The elimination of pin by make the connector directly fit to wiper holder is an idea resulted from element in Principle 1. Figure 6.13 and Figure 6.14 show the result of new design of connector and wiper holder. Lock Pin Figure 6.13: New design of connector based on idea from element in Principle 1. Pin Hole Figure 6.14: New design of wiper holder that designing to fit with the new connector design. 79 6.4 Summary Through implementation of the DFMA Methodology and TRIZ Concept several parts had been improved or been eliminated or combined. As a result, there are ten improvements not excluded the elimination part had been determined through DFMA analysis while the integrating of the TRIZ with DFMA had resulted six improvements from the four problem design cases. CHAPTER 7 DFMA AND TRIZ ANALYSIS FOR NEW DESIGN 7.1 Introduction This chapter discusses about the analysis results for new design of sponge mop. There two sections which are analysis result of new design using DFMA methodology and analysis result of new design using TRIZ concept. It consist of exploded view of the new design, bill of materials, justification and sketches of new design, classification of each part for manual handling and manual insertion, worksheet analysis, estimated assembly time and cost, and the new design efficiency. Besides that, selection of materials and processes for a new designing part of DFMA also will be explained in this chapter. 81 7.2 DFMA Analysis for New Design This section will discusses about the analysis results of new sponge mop design by using DFMA methodology. Figure 7.1 shows the new design of Sponge Mop. 13 14 3 10 12 2 1 15 1 5 8 9 6 5 7 4 Figure 7.1: Exploded drawing of new design of Sponge Mop via DFMA Methodology. 11 82 7.2.1 Classification of Product Parts The implementation of the DFA methodologies had influenced the degree of part symmetry as the consideration to make part easy to handle and insert are measured. Low values of part symmetry degree will smaller two digits code for manual handling and insertion time. Thus, it will result less value of time taken to assembly the part. Table 7.1 shows the analysis of classification of product part for the new design. Table 7.1: Classification of Part for New Design by DFMA Methodology Manual Handling Alpha (α) Beta (β) 1 (connector) 360o 180o Manual Handling Code 20 2 (wiper Holder) 360o 360o 30 30 360 o 180 o 20 31 360 o 180 o 20 30 5 (Knob) 360 o 180 o 20 30 6 (Male Adjuster) 360o 180o 20 30 360 o 180 o 20 30 360 o 180 o 20 00 360 o 0 o 10 00 180 o 0 o 00 30 360 o 0 o 10 30 12 (Snap fit shaft 3) 360 o 0 o 10 30 13 (Handle) 360o 360o 30 06 360 o 360 o 30 30 360 o 180 o 20 30 Part 3 (Wiper) 4 (Female Adjuster) 7 (Stopper) 8 (Rod A) 9 (Rod B) 10 (Snap fit shaft 1) 11 (Snap fit shaft 2) 14 (Pusher) 15 (Joint) Manual Insertion Code 30 83 7.2.2 Theoretical Minimum Parts Assessment Basically, the value of theoretical minimum number of part for all part of new design is one (1). This is because the analysis of new design required elimination value of zero (0). However, it is doesn’t mean that the part can’t be improve in the future. Others problem solving can be used is by joining or combined two or more parts. 7.2.3 DFA Worksheet DFA worksheet will show the result of the analysis of the product, sponge mop. In this section, the analysis is done for the new design of the sponge mop by using DFMA Methodology. 84 Table 7.2: DFA worksheet analysis for new design by DFMA methodology. c5 c6 c7 c8 c9 2 3.8 0.39596 1 Add 2 30 1.95 30 2 7.9 0.82318 2 Add 1 20 1.8 30 2 3.8 0.39596 1 1 20 1.8 30 2 3.8 0.39596 1 1 20 1.8 30 2 3.8 0.39596 1 Add Add and snap Fit Add 1 20 1.8 30 2 3.8 0.39596 1 Add 7(Stopper) 1 20 1.8 30 2 3.8 0.39596 1 8(Rod A) 9(Rod B) 10(Snap fit shaft 1) 11(Snap fit shaft 2) 12(Snap fit shaft 3) 1 1 20 10 1.8 1.5 00 00 1.5 1.5 3.3 3 0.34386 0.3126 1 1 2 00 1.13 31 5 13 1.3546 2 1 10 1.5 30 2 3.5 0.3647 1 1 10 1.5 30 2 3.5 0.3647 1 13(Handle) 1 30 1.95 06 5.5 7.45 0.77629 1 14Pusher 1 30 1.95 30 2 3.95 0.41159 1 15(Joint) 1 20 1.8 2 3.8 0.39596 1 71.46 7.4461 17 TM CM NM 30 Estimation for theoretical minimum parts 30 Operation cost (cent) 1.8 Operation time( sec) 20 1(connector) 2(wiper Holder) 3(Wiper) 4(Female Adjuster) 5(Knob) 6(Male Adjuster) Manual insertion time per part 1 Part ID Manual handling time per part c4 Manual handling code c3 Manual insertion code c2 Number of times the operation is carried out consecutively c1 Total: Name of Assembly Add and Snap Fit Add Add Add and Snap Fit Add and Snap Fit Add and Snap Fit Add and Hold Down Add and Hold Down Add and Hold Down Design efficiency = 3 NM/TM= 71.37% 85 7.2.4 Results From the DFA worksheet analysis, the results of the estimated time, cost and design efficiency of the assembly are obtained. Below are the summary of the result for the new design analysis. Total assembly time, TM = 71.46 secs. Total assembly cost, CM = 7.4461cents. Theoretical minimum number of part, NM = 17 Design efficiency, DE = 71.37% Note: 1) The value of total assembly cost (CM) is gained from the calculation below: Value of labor cost per second (n) may vary due to different assumption and for this case study, below n assumption is used. - Monthly salary for one operator = RM 600 - Number of working day = 20 days/month - Number of working hour/day = 8 hours/day So, labor cost per second, n = RM 600 / (20 days x 8 hours x 3600secs) = RM 0.001042/sec = 0.1042 cents/sec Thus, CM = TM x n = 71.46 secs x 0.1042 cents/sec = 7.4461cents. 86 2) The design efficiency of the original design is gained by using below formula; DE = 3 x NM x 100% TM = (3 x 17/ 71.46 s) x 100% = 0.7137 x 100% = 71.37% 7.2.5 DFM Analysis Design for Manufacture (DFM) analysis is an analysis that conducted to select the suitable material and manufacturing process for each part of product case study. The result of analysis is determine by match out the part attributes of each part with the table shape generation capabilities of processes [Appendix 2G] and continuing by matching with the compatibility matrix for a final selection of material and manufacturing process [Appendix 2F]. The part attributes of each part for a new design of Sponge Mop is shown in Appendix 7A while Appendix 7B shows the final result of material and manufacturing process of each part. From the overall result, thermoplastic material and injection molding process are widely used in producing new design of Sponge Mop. 87 7.3 TRIZ Analysis for New Design This section will discuss about the analysis results of new sponge mop design by using TRIZ concept. In this project case study, the analysis of design efficiency of the product is done by applying DFA analysis. This is because for the clear comparison purposes. Figure 7.2 shows the new design of Sponge Mop after TRIZ elements are applying on it. 2 14 3 13 11 15 4 1 6 12 9 7 5 8 Figure 7.2: Exploded view of new design of Sponge Mop via TRIZ Concept. 88 7.3.1 Classification of Product Part The implementation of the DFA methodologies had influenced the degree of part symmetry as the consideration to make part easy to handle and insert are measured. Low values of part symmetry degree will smaller two digits code for manual handling and insertion time. Thus, it will result less value of time taken to assembly the part. Table 7.3 shows the analysis of classification of product part for the new design. Table 7.3: Classification of Part for New Design by TRIZ Concept Manual Handling Part Alpha (α) Beta (β) 360o 180o 180 o 180 o 360 o 180 o 180 o o 360 o 180 360 o o 7 (Stopper) 360 o 8 (Rod A) 360o 1 (connector) 2 (wiper Holder) 3 (Wiper) 4 (Female Adjuster) 5 (Knob) 6 (Male Adjuster) 9 (Rod B) 11 (Snap fit shaft 2) 12 (Snap fit shaft 3) 13 (Handle) 14 (Pusher) 15 (Joint) 360 o 180 o 180 o 360 o 360 o 360 o 0 0 180 o o 180o 0 o 0 o 0 o 360 o 360 o 180 o Manual Manual Handling Insertion Code Code 20 30 20 00 20 31 00 00 20 30 10 30 20 30 20 00 10 00 10 30 10 30 30 06 30 30 20 30 89 7.3.2 DFA Worksheet DFA worksheet will show the result of the analysis of the product, sponge mop. In this section, the analysis is done for the new design of the sponge mop by using TRIZ concept. Table 7.4: DFA worksheet analysis for new design by TRIZ. c5 c7 c8 c9 3.8 0.39596 1 Add 2 20 1.8 00 1.5 6.6 0.68772 2 Add 1 20 1.8 30 2 3.8 0.39596 1 Add 1 00 1.13 00 1.5 2.63 0.27405 1 Add 1 20 1.8 30 2 3.8 0.39596 1 Add 1 10 1.5 30 2 3.5 0.36470 1 Add 7(Stopper) 1 20 1.8 30 2 3.8 0.39596 1 8(Rod A) 9(Rod B) 11(Snap fit shaft 2) 12(Snap fit shaft 3) 1 1 20 10 1.8 1.5 00 00 1.5 1.5 3.3 3 0.34386 0.31260 1 1 1 10 1.5 30 2 3.5 0.36470 1 1 10 1.5 30 2 3.5 0.36470 1 13(Handle) 1 30 1.95 06 5.5 7.45 0.77629 1 14Pusher 1 30 1.95 00 1.5 3.45 0.41159 1 15(Joint) 1 20 1.8 30 2 3.8 0.39596 1 55.93 5.8279 15 TM CM NM Total: Estimation for theoretical minimum parts 2 0.1042 x (c7) 30 Operation cost (cent) 1.8 (2) x [(4) + (6)] 20 1(connector) 2(wiper Holder) 3(Wiper) 4(Female Adjuster) 5(Knob) 6(Male Adjuster) Manual handling time per part 1 Part ID Operation time( sec) c6 Manual insertion time per part c4 Manual insertion code c3 Manual handling code c2 Number of times the operation is carried out consecutively c1 Name of Assembly Add and Snap Fit Add Add Add and Snap Fit Add and Snap Fit Add and Hold Down Add and Hold Down Add Design efficiency = 3 NM/TM= 80.46% 90 7.3.3 Results From the DFA worksheet analysis, the results of the estimated time, cost and design efficiency of the assembly are obtained. Below are the summary of the result for the new improvement design of Sponge Mop by TRIZ concept analysis. Total assembly time, TM = 55.93 secs. Total assembly cost, CM = 5.8279 cents. Theoretical minimum number of part, NM = 15 Design efficiency, DE = 80.46% Note: 1) The value of total assembly cost (CM) is gained from the calculation below: Value of labor cost per second (n) may vary due to different assumption and for this case study, below n assumption is used. - Monthly salary for one operator = RM 600 - Number of working day = 20 days/month - Number of working hour/day = 8 hours/day So, labor cost per second, n = RM 600 / (20 days x 8 hours x 3600secs) = RM 0.001042/sec = 0.1042 cents/sec Thus, CM = TM x n = 55.93 secs x 0.1042 cents/sec = 5.8279 cents. 91 2) The design efficiency of the original design is gained by using below formula; DE = 3 x NM x 100% TM = (3 x 15/ 55.93 s) x 100% = 0.8046 x 100% = 80.46% 7.3.4 DFM Analysis The part attributes of each part for a new design of Sponge Mop by TRIZ concept analysis is shown in Appendix 7C while Appendix 7D shows the final result of material and manufacturing process of each part. From the overall result, again thermoplastic material and injection molding process are widely used in producing parts for this new improvement design. 7.4 Summary From the DFA analysis result, the values of both new improvement designs are determined. Both design efficiency of the new design had improved the old design efficiency. So, it means the objective of improvement is achieved. CHAPTER 8 DISCUSSION 8.1 Introduction This chapter discusses about the comparisons result between Sponge Mop original designs with both new Sponge Mop improvement design. Besides that, the differences result between both problem solving design tool also been discussed. As state earlier, the problem solving design tools used in this case study are DFMA methodology and TRIZ concept. However, in TRIZ concept it is more to integrating the concept with the DFMA methodology. In this case study, TRIZ concept is applying after DFMA methodology. 93 8.2 Comparisons of Product Case Study Result This section consists of discussion about comparisons of DFMA analysis result, comparisons of TRIZ analysis result, and comparisons between DFMA and TRIZ improvement result. 8.2.1 Comparisons of DFMA Analysis Result The comparisons of DFMA analysis result are based on the original design and new design of Sponge Mop by applying Boothroyd-Dewhurst DFMA Methodology. Table 8.1 shows the comparisons between original and new design. Comparison of the items resulted effect of the improvement. Table 8.1: Effect of the improvement. Original New Percentage of Increment Design design /Reduction Number of Part 30 17 43.33% of reduction Different Number of Part 21 15 28.57% of reduction Total Assembly Time 194.93 s 71.46 s 63.34% of reduction Total Assembly Cost 20.3117 cent 7.4461 cent 63.34% of reduction Design Efficiency 23.09% 71.37% Item 209.09% of increment Table 8.1 indicates the effects of the improvements that had been made on the original design of the sponge mop. The effects of the improvements were dramatically viewed especially in the design efficiency. The value of 209.09% increment shows that the implementing of Boothroyd-Dewhurst DFA methodology in product design will ensure in increasing the design efficiency of a product. From the table, it clearly shows that the increment of design efficiency is influence by the 94 achievement on reducing the number of part and assembly time of the product case study. Besides that, the achievement on reducing number of part and assembly time had reducing the cost to assemble the new design of product case study. High percentage improvement is achieved in reducing the total assembly time compared to the percentage improvement of number of part which is only 28.57%. So, it’s shows that even the improvement of product can’t be improve through reducing the number of part, the improvement can be done by simplifying the part of the product such as make the part symmetry, design the part to easy to handle and insertion. Table 8.2 shows the effects of design changes in terms of time saving. Basically, time saving is slightly due to the two concerns when conducting Boothroyd-Dewhurst DFA analysis which are by combining and eliminating the parts. However, simplified the assembly process also will resulted the time saving. Table 8.2: Result of time saving due to the factor of design change. No 1 2 3 4 Design Change Connector (eliminated arms and pins) Eliminate one pusher, handle bracket, ring, Redesign wiper holders, female and male adjuster, stopper, Rod A, handle, and joint. Eliminating screws and nuts Items Time Saving (s) 1, 3, 7 45.02 14, 16, 19, 17.85 5, 6, 9, 11, 12, 13, 17 17.65 2, 18, 21 28.5 From the Table 8.2, the major contributor of time saving for the new design of Sponge Mop is by redesign the connector part. The new design of connector had eliminated the used of arms and pins as from the DFA evaluation, these two parts is not necessary which means the connector can operate by itself. In this case study, the connector had been redesign (refer Chapter 6) to directly attached to the wiper part. The next design factors that contributing in time saving is the elimination of screws 95 and nuts by proposing snap fit mechanism. This elimination totally resulted high saving time as assembly time of screw and nut are the highest compared to others mating mechanism. 8.2.2 Comparisons of TRIZ Analysis Result The discussion on the comparisons of TRIZ analysis result in this section is more on the improvement process that had been done on the part of product case study. If in the DFMA, quantitative is the main consideration however in TRIZ, the qualitative becoming the main consideration. Besides that, the different value of time assembly also will be discussed. Table 8.3 shows the effect of the improvement result. Table 8.3: Effect of the improvement result. Item Pusher Description Improvement Remark The aim is to reduce Eliminate one pusher by The improvement the number of pusher. combining In original the two through TRIZ had design, pushers. The new design reduced assembly two pushers are used still remains the same about 0.5 seconds to make the product strength function. with the However, design. The used of pin the strength of the also be eliminated. part should constant. old from the DFMA. be 96 Table 8.3: Continued. Item Male and Description Improvement The aim is to make Changing operation Remark threading The improvement of mechanism into snap clip through TRIZ had Female the Adjuster assembly more easily mechanism. The new reduced assembly but in the same time mechanism remains the about 0.47 seconds the strength of mating strength. The transparent from parts should ever color of material is used in The order lasted. the to make DFMA. qualitative the value of part is also assembly operation more improved. easily. Joint The consideration of No improvement in terms The improvement of joint is to reduce the of design done. this is part harmful effect make However, improvement is influencing by pusher. However, done by changing not the the assembly time but in the force required by material of the joint same terms of the quality pusher to make the as product material functioning Same can’t be less. material of pusher. of the part. characteristic will less possibility to damage. of the 97 Table 8.3: Continued. Item Description Improvement Wiper The aim of these parts Arms Holder, is to reduce are The improvement by through TRIZ had part. redesigning the wiper reduced assembly the eliminated Connector, number Arms and However, elimination holder and Pins of and pins Remark connector about 1.7 seconds of part may disturb part. Both improvement from the DFMA. the ease of parts are directly being maintenance of other assembled together and parts. the improvements are not influenced process of maintenance for joint part. In DFMA, the maintenance process of joint will make the wiper separated from connector and required down holding during insertion assembly process. of 98 8.2.3 Comparisons between DFMA and TRIZ Improvement Result This section will discuss about the effect of the improvement of integrating the DFMA methodology and TRIZ concept. The improvement is compared with the analysis done by the DFMA methodology alone. Table 8.4 shows the comparisons between DFMA new design analysis result and integrating DFMA and TRIZ analysis results. Table 8.4: Effect of the improvement DFMA + Different TRIZ Percentage 17 15 11.76% of reduction Total Assembly Time 71.46 s 55.93 s 21.73% of reduction Total Assembly Cost 7.4461 cents 5.8279 cents 21.73% of reduction Design Efficiency 71.37% 80.46% 12.74% of increment Item DFMA Theoretical Minimum Number of part From the Table 8.4, the results showed that the analysis result done by the integrating two design problem solving tools gave a high improvement percentage compared to the analysis done by DFMA Methodology only. The integration tools had minimized the theoretical minimum number of part into 15 parts with percentage of reduction from the new design DFMA analysis is equal to 11.76%. Besides that, the integrating two design problem solving tools also resulted in the achievement to reduce the product assembly time and cost. The achievement had resulted 21.73% of reduction from the new design DFMA analysis. Lastly, the result showed that the integration of DFMA and TRIZ had increased the design efficiency of the new Sponge Mop into 80.46%. It means that the qualitative factor influenced 99 the value of the design efficiency percentage. The increasing result, dramatically affect the improvement by 12.74% of increment. Even though the percentage of improvements is low, the objective to show that integrating problem solving tools will give more impact in term of result is achieved. 8.3 Summary In summary, the used of integrating DFMA methodology and TRIZ concept in the improvement product stage will give more value added to the result. This is because, TRIZ not only giving benefit in term of quantitative but also in term of qualitative. However, the other conclusion can be done is the application of Boothroyd-Dewhurst DFMA methodology dramatically will increase the value of product design efficiency in term of assembly process. CHAPTER 9 CONCLUSION 9.1 Introduction This chapter concluded the thesis case study. Besides that, future work recommendation also will be highlighted in this chapter. From the study that had been done, the objective to integrate Theory of Inventive Problem Solving (TRIZ), and Design for Manufacture and Assembly (DFMA) methodology in order to improve the design of consumer product has been met. TRIZ concept by using contradiction philosophy had been selected because it shows the ways how one factor needs to be considered if another factor is going to be changed and the result shows the used of integrating DFMA and TRIZ really give a better result compared to use only one design problem solving tool. 101 9.2 Recommendations for Future Work In this thesis, the improvement of product design is proposed by integrating DFMA and TRIZ, where the application of TRIZ had booster the DFMA analysis result. So, it had proved that integration of more than one design problem solving tool will resulted better result. However, in this thesis, the application of TRIZ tool is not fully utilized as it had been constrain by the product case study selected and also time to explore it. Below are the several recommendations for future work: 1. Integrate TRIZ with other design analysis methodology or design problem solving tool such as Design for Robustness (DFR) as our technology now a days is going for this area. Robust design is a set of engineering methods for attaining high-quality function despite variations due to manufacturing, the environment, deterioration, and customer use patterns. The fundamental principle of robust design is to improve the quality of the product by minimizing the effects of variation without eliminating the causes [Phadke, 1989]. The methodology that was used is similar to that employed by Altshuller [1984] in developing TRIZ. Altshuller screened several patents looking for inventive problem and how they were solved. He ultimately came to the conclusion that patents can be best classified on the basis of how they overcome contradictions in previously existing engineering systems. It was found that Altshuller’s research approach to be of great value. This research approach is composed of four steps: a. Collect a large body of inventions related to robustness. b. Analyze the inventions in detail to understand how they achieved improved robustness. c. Seek useful classification principles for the inventions. d. Develop a database organized around the classification principles. 102 2. Integration of the TRIZ and DFMA by utilizing other additional TRIZ tool where more difficult problems are solved with this more precise tool which is the application of ARIZ (Algorithm for Inventive Problem Solving). ARIZ is a systematic procedure for identifying solutions without apparent contradictions. Depending on the nature of the problem, anywhere from five to sixty steps may be involved. From an unclear technical problem, the underlying technical problem can be revealed. Can be used with levels two, three, and four problems. Basic steps included: a. Formulate the problem. b. Transform the problem into a model. c. Analyze the model. d. Resolve physical contradiction. e. Formulate ideal solution. 3. The other recommendation is to integrate more than two design problem solving tools to make an improvement of a product. One of the suggestions is to integrate between QFD, TRIZ and FMEA in conceptual design for product development process. 103 9.3 Concluding Remark As a conclusion, TRIZ is a systematic methodology for product simplification which is the problem solving is based on guidelines not try and error. In other word, TRIZ proposed ‘how to solve’ not ‘what to solve’. TRIZ will create potential design solutions, resolve design contradiction and increase design option. The integration of DFMA methodologies with TRIZ had helped a lot in reducing the number of parts in a design improvement. By reducing the number of parts, the assembly time and costs are significantly reduced. Besides that, the DFA guidelines are very valuable information in the design improvement process. While, DFM analysis selected the best material and manufacturing process for the component parts of the assembly. 105 REFERENCES 1. Lucchetta, G., Bariani, P. F., Knight. W. A., Integrated Design Analysis for Product Simplification. University of Padova, Italy. 2. Triz-journal.com. Utilization of TRIZ with DFMA to Maximize Value [Online]. Available: http://www.triz-journal.com. [2009, July 21] 3. Wikipedia. Value Engineering [Online]. Available: http://en.wikipedia.org/wiki/Value_engineering. [2009, July 9] 4. Wikipedia. TRIZ [Online]. Available: http://en.wikipedia.org/wiki/TRIZ. [2009, July 20]. 5. Darell. L. Mann. Integration and Application of TRIZ and DFMA. Systematicinnovation.com. 2002. 6. Kai Yang., Basem, E.H. Design for Six Sigma – A Roadmap for Product Development. New York: McGraw-Hill. 2003. 7. Altshuller, G. and Henry. The Art of Inventiving (And Suddenly the Inventor Appeared). Technical Innovation Center. 1994. 8. Rajesh. J., Philip. S. Design for Six Sigma – A Holistic Approach to Design and Innovation. New Jersey: Wiley. 2008. 9. Boothroyd, G . and Dewhurst, P. Product Design for Manufacture and Assembly. New York: Marcel Dekkel. 2002. 10. Zhongsheng Hua, Jie Yang, Solomani Coulibaly, and Bin Zhang. Integration TRIZ with Problem Solving Tools: A Literature Review From 1995 to 2006. International Journal Business Innovation and Research, Vol 1. 2006. 11. Triz-journal.com (2009). Innovation; The next Frontier for Six Sigma [Online]. Available: http://www.triz-journal.com. [2009, July 27] 106 12. Chung-Shing, W. and Teng-Ruey, C. Integrated QFD, TRIZ and FMEA in Conceptual Design for Product Development Process. Proceedings of the 13th Asia Pacific Management Conference. Melbourne, Australia: APMR. 2007. 1085-1095. 13. Ideationtriz.com. Ideation/TRIZ: Innovation Key to competitive Advantage and Growth [Online]. Available: http://www.ideationtriz.com/paper_ITIRZ_Innovation_Key.htm. 2009. 14. Daniela, S., Elena, M., Nicolae, I. and Thomas, R. A TRIZ Approach to Design for Environment. Galway Mayo Institute of Technology. Unpublished. 15. Darell. L. Mann. Beyond Systematic Innovation: Integration of Emergence and Recursion Concepts into TRIZ and Other Tools. Systematicinnovation.com. 2002. 16. Valery, K., Jun-Young, L. and Jeong-Bai, L. TRIZ Improvement of Rotary Compressor Design. Proceedings of TRIZCON2005, the annual conference of the Altshuller Institute, Brighton, MI USA: 2005. 17. Noel, L. R. A Proposal to Integrate TRIZ into the Design Product Process [Online]. Available: http://www.trizjournal.com/archives/2002/11/b/index.htm. 2002. 18. Masaya, T. and Manabu, S. The Possibility of VE Activities as New Product Planning by Utilizing TRIZ Techniques. The SANNO Institute of Management, Tokyo, Japan. 19. Ahmad Humaizi Bin Hilmi. Design and Analysis of a Paintball Marker Using Boothroyd-Dewhurst DFMA Methodology. Master Thesis. Universiti Teknologi Malaysia; 2005. 20. Noor Laili Binti Ali, Design for Assembly: Design Improvements for Assembled Product Using Boothroyd-Dewhurst DFMA Methodology. Bachelor Project Thesis. Universiti Teknologi Malaysia: 2009. 107 21. Chong Teik Seng, Development of the Prototype System for Design for Assembly (DFA) Using Boothroyd-Dewhurst DFMA Methodology. Bachelor Project Thesis. Universiti Teknologi Malaysia: 2006. 22. Baizura Binti Zubir @ Zubair. Assemblability Design Effieciency (ADE) Analyses for Design for Automatic Assemblies (DFAA). Master Thesis. Universiti Teknologi Malaysia; 2008. 108 APPENDICES Writing report Oral Presentation 1 Submit draft report Evalute the new design (apply DfMA only) Propose improvement Identify and select possible solution Evaluate original product design Select consumer product Literature Review on Value Engineering, DfMA and TRIZ Methodology Select Project Title PROJECT ACTIVITIES A P P A A P A P A P A P A P A P A P A P Week 12 Week 11 Week 10 Week 9 Week 8 Week 7 Week 6 Week 5 Week 4 Week 3 Week 2 Week 1 APPENDIX 1A - GANTT CHART 1: PROJECT ACTIVITIES FOR MASTER PROJECT PART 1 Week 15 Week 14 Week 13 109 Writing report Oral Presentation 2 Submit draft report Discussion and conclusion Analysis the overall project Evalute the new design (apply DfMA & TRIZ) Evalute the new design (apply DfMA only) Propose improvement PROJECT ACTIVITIES A P A P A P A P A P A P A P A P Week 12 Week 11 Week 10 Week 9 Week 8 Week 7 Week 6 Week 5 Week 4 Week 3 Week 2 Week 1 APPENDIX 1B - GANTT CHART 2 PROJECT ACTIVITIES FOR MASTER PROJECT PART 2 Week 15 Week 14 Week 13 110 111 APPENDIX 2A – CONTRADICTION TABLE OF 39 PARAMETERS 112 113 114 115 116 117 APPENDIX 2B – THE 40 INVENTIVES PRINCIPLES 1. Segmentation a. Divide an object into independent parts b. Make an object sectional c. Increase the degree of an object's segmentation Examples: 2. • Sectional furniture, modular computer components, folding wooden ruler • Garden hoses can be joined together to form any length needed Extraction a. Extract (remove or separate) a "disturbing" part or property from an object, or b. Extract only the necessary part or property Example: • To frighten birds away from the airport, use a tape recorder to reproduce the sound known to excite birds. (The sound is thus separated from the birds.) 3. Local Quality a. Transition from a homogeneous structure of an object or outside environment/action to a heterogeneous structure b. Have different parts of the object carry out different functions c. Place each part of the object under conditions most favorable for its operation Examples: • To combat dust in coal mines, a fine mist of water in a conical form is applied to working parts of the drilling and loading machinery. The smaller the droplets, the greater the effect in combating dust, but fine mist 118 hinders the work. The solution is to develop a layer of coarse mist around the cone of fine mist. • 4. A pencil and eraser in one unit. Asymmetry a. Replace a symmetrical form with an asymmetrical form. b. If an object is already asymmetrical, increase the degree of asymmetry Examples: • Make one side of a tire stronger than the other to withstand impact with the curb • While discharging wet sand through a symmetrical funnel, the sand forms an arch above the opening, causing irregular flow. A funnel of asymmetrical shape eliminates the arching effect. 5. Combining a. Combine in space homogeneous objects or objects destined for contiguous operations b. Combine in time homogeneous or contiguous operations Example: • The working element of a rotary excavator has special steam nozzles to defrost and soften the frozen ground. 6. Universality Have the object perform multiple functions, thereby eliminating the need for some other object(s). Examples: • Sofa which converts into a bed • Minivan seat which adjusts to accommodate seating, sleeping or carrying cargo. 119 7. Nesting a. Contain the object inside another which, in turn, is placed inside a third object b. Pass an object through a cavity of another object Examples: 8. • Telescoping antenna • Chairs which stack on top of each other for storage • Mechanical pencil with lead stored inside Counterweight a. Compensate for the object's weight by joining with another object that has a lifting force b. Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces Examples: • Boat with hydrofoils. • A rear wing in racing cars which increases pressure from the car to the ground. 9. Prior counter-action a. Perform a counter-action in advance. b. If the object is (or will be) under tension, provide anti-tension in advance. Examples: • Reinforced concrete column or floor. • Reinforced shaft made from several pipes which have been previously twisted to some specified angle. 10. Prior action a. Carry out all or part of the required action in advance b. Arrange objects so they can go into action in a timely matter and from a convenient position Examples: 120 • Utility knife blade made with a groove allowing the dull part of the blade to be broken off, restoring sharpness • Rubber cement in a bottle is difficult to apply neatly and uniformly. Instead, it is formed into a tape so that the proper amount can be more easily applied. 11. Cushion in advance Compensate for the relatively low reliability of an object by countermeasures taken in advance. Example: • 12. Merchandise is magnetized to deter shoplifting. Equipotentiality Change the working conditions so that an object need not be raised or lowered. Example: • Automobile engine oil is changed by workers in a pit to avoid using expensive lifting equipment 13. Inversion a. Instead of an action dictated by the specifications of the problem, implement an opposite action b. Make a moving part of the object or the outside environment immovable and the non-moving part movable c. Turn the object upside-down Example: • 14. Abrasively cleaning parts by vibrating the parts instead of the abrasive Spheroidality a. Replace linear parts or flat surfaces with curved ones; replace cubical shapes with spherical shapes b. Use rollers, balls spirals 121 c. Replace a linear motion with rotating movement; utilize a centrifugal force Example: • Computer mouse utilized ball construction to transfer linear two-axis motion into vector motion 15. Dynamicity a. Make an object or its environment automatically adjust for optimal performance at each stage of operation b. Divide an object into elements which can change position relative to each other c. If an object is immovable, make it movable or interchangeable Examples: • A flashlight with a flexible gooseneck between the body and the lamp head • A transport vessel with a cylindrical-shaped body. To reduce the draft or a vessel under full load, the body is comprised of two hinged, halfcylindrical parts which can be opened. 16. Partial or overdone action If it is difficult to obtain 100% of a desired effect, achieve somewhat more or less to greatly simplify the problem. Examples: • A cylinder is painted by dipping into paint, but contains more paint than desired. Excess paint is then removed by rapidly rotating the cylinder. • To obtain uniform discharge of a metallic powder from a bin, the hopper has a special internal funnel which is continually overfilled to provide nearly constant pressure. 17. Moving to a new dimension a. Remove problems with moving an object in a line by two-dimensional movement (i.e. along a plane) 122 b. Use a multi-layered assembly of objects instead of a single layer c. Incline the object or turn it on its side Example: • A greenhouse which has a concave reflector on the northern part of the house to improve illumination of that part of the house by reflecting sunlight during the day. 18. Mechanical vibration a. Set an object into oscillation b. If oscillation exists, increase its frequency, even as far as ultrasonic c. Use the resonant frequency d. Instead of mechanical vibrations, use piezovibrators e. Use ultrasonic vibrations in conjunction with an electromagnetic field Examples: • To remove a cast from the body without injuring the skin, a conventional hand saw was replaced with a vibrating knife. • Vibrate a casting mold while it is being filled to improve flow and structural properties. 19. Periodic action a. Replace a continuous action with a periodic (pulsed) one. b. If an action is already periodic, change its frequency. c. Use pulsed between impulses to provide additional action. Examples: • An impact wrench loosens corroded nuts using impulses rather than continuous force. • A warning lamp flashes so that it is even more noticeable than when continuously lit. 123 20. Continuity of a useful action a. Carry out an action continuously (i.e. without pauses), where all parts of an object operate at full capacity. b. Remove idle and intermediate motions. Example: • A drill with cutting edges which permit cutting in forward and reverse directions. 21. Rushing through Perform harmful or hazardous operations at very high speed. Example: • A cutter for thin-walled plastic tubes prevents tube deformation during cutting by running at a very high speed (i.e. cuts before the tube has a chance to deform). 22. Convert harm into benefit a. Utilize harmful factors or environmental effects to obtain a positive effect. b. Remove a harmful factor by combining it with another harmful factor. c. Increase the amount of harmful action until it ceases to be harmfull. Examples: • Sand or gravel freezes solid when transported through cold climates. Overfreezing (using liquid nitrogen) makes the ice brittle, permitting pouring. • When using high frequency current to heat metal, only the outer layer became hot. This negative effect was later used for surface heat-treating. 23. Feedback a. Introduce feedback. b. If feedback already exists, reverse it. Examples: 124 • Water pressure from a well is maintained by sensing output pressure and turning on a pump if pressure is too low. • Ice and water are measured separately but must combine to total a specific weight. Because ice is difficult to dispense precisely, it is measured first. The weight is then fed to the water control device, which precisely dispenses the needed amount. 24. Mediator a. Use an intermediary object to transfer or carry out an action. b. Temporarily connect an object to another one that is easy to remove. Example: • To reduce energy loss when applying current to a liquid metal, cooled electrodes and intermediate liquid metal with a lower melting temperature are used. 25. Self-service a. Make the object service itself and carry out supplementary and repair operations b. Make use of wasted material and energy Examples: • To prevent wear in a feeder which distributes an abrasive material, its surface is made from the abrasive material • In an electric welding gun, the rod is advanced by a special device. To simplify the system, the rod is advanced by a solenoid controlled by the welding current. 26. Copying a. Use a simple and inexpensive copy instead of an object which is complex, expensive, fragile or inconvenient to operate. b. Replace an object by its optical copy or image. A scale can be used to reduce or enlarge the image. 125 c. If visible optical copies are used, replace them with infrared or ultraviolet copies. Example: • 27. The height of tall objects can be determined by measuring their shadows. Inexpensive, short-lived object for expensive, durable one Replace an expensive object by a collection of inexpensive ones, forgoing properties (e.g. longevity) Examples: • 28. Disposable diapers. Replacement of a mechanical system a. Replace a mechanical system by an optical, acoustical or olfactory (odor) system. b. Use an electrical, magnetic or electromagnetic field for interaction with the object. c. Replace fields 1. Stationary fields with moving fields. 2. Fixed fields with those which change in time. 3. Random fields with structured fields. d. Use a field in conjunction with ferromagnetic particles. Example: • To increase the bond between metal coating and a thermoplastic material, the process is carried out inside an electromagnetic field which applies force to the metal. 29. Pneumatic or hydraulic construction Replace solid parts of an object by gas or liquid. These parts can use air or water for inflation, or use air or hydrostatic cushions. Examples: 126 • To increase the draft of an industrial chimney, a spiral pipe with nozzles was installed. When air flows through the nozzles, it creates an air-like wall, reducing drag. • For shipping fragile products, air bubble envelopes or foam-like materials are used. 30. Flexible membranes or thin film a. Replace traditional constructions with those made from flexible membranes or thin film. b. Isolate an object from its environment using flexible membranes or thin film. Example: • To prevent water evaporation from plant leaves, polyethylene spray was applied. After a while, the polyethylene hardened and plant growth improved, because polyethylene film passes oxygen better than water vapor. 31. Use of porous material a. Make an object porous or add porous elements (inserts, covers, etc.). b. If an object is already porous, fill the pores in advance with some substance. Example: • To avoid pumping coolant to a machine, some of its parts are filled with a porous material soaked in coolant liquid. The coolant evaporates when the machine is working, providing short-term uniform cooling. 32. Changing the color a. Change the color of an object or its surroundings. b. Change the degree of translucency of an object or processes which are difficult to see. 127 c. Use colored additives to observe objects or processes which are difficult to see. d. If such additives are already used, employ luminescent traces or tracer elements. Examples: • A transparent bandage enabling a wound to be inspected without removing the dressing. • A water curtain used to protect steel mill workers from overheating blocked infrared rays but not the bright light from the melted steel. A coloring was added to the water to create a filter effect while preserving the transparency of the water. 33. Homogeneity Make those objects which interact with a primary object out of the same material or material that is close to it in behavior. Example: • The surface of a feeder for abrasive grain is made of the same material that runs through the feeder, allowing a continuous restoration of the surface. 34. Rejecting and regenerating parts a. After it has completed its function or become useless, reject or modify (e.g. discard, dissolve, evaporate) an element of an object. b. Immediately restore any part of an object which is exhausted or depleted. Examples: 35. • Bullet casings are ejected after the gun fires • Rocket boosters separate after serving their function Transformation of the physical and chemical states of an object Change an object's aggregate state, density distribution, degree of flexibility, temperature. 128 Example: • In a system for brittle friable materials, the surface of the spiral feedscrew was made from an elastic material with two spiral springs. To control the process, the pitch of the screw could be changed remotely. 36. Phase transformation Implement an effect developed during the phase transition of a substance. For instance, during the change of volume, liberation or absorption of heat. Example: • To control the expansion of ribbed pipes, they are filled with water and cooled to a freezing temperature. 37. Thermal expansion a. Use a material which expands or contracts with heat. b. Use various materials with different coefficients of heat expansion. Example: • To control the opening of roof windows in a greenhouse, bimetallic plates are connected to the windows. A change in temperature bends the plates, causing the window to open or close. 38. Use strong oxidizers a. Replace normal air with enriched air. b. Replace enriched air with oxygen. c. Treat an object in air or in oxygen with ionizing radiation. d. Use ionized oxygen. Example: • To obtain more heat from a torch, oxygen is fed to the torch instead of atmospheric air. 39. Inert environment a. Replace the normal environment with an inert one. 129 b. Carry out the process in a vacuum. Example: • To prevent cotton from catching fire in a warehouse, it is treated with inert gas while being transported to the storage area. 40. Composite materials Replace a homogeneous material with a composite one. Example: • Military aircraft wings are made of composites of plastics and carbon fibers for high strength and low weight. 3 4 5 6 7 8 9 Part ID # # of times the operation is carried out consecutively Two-digit manual handling code Manual handling time per part Two-digit manual insertion code Manual insertion time per part Estimation of theoretical minimum # of parts, 0 or 1 2 Operation cost, cents, 0.4 (US) x (7) 1 Operation time, sec, (2) x [(4) + (7)] 0 Name of Part 130 Appendix 2C – DFA Worksheet 1 0 0 0 2 0 0 0 3 0 0 0 4 0 0 0 5 0 0 0 6 0 0 0 7 0 0 0 8 0 0 0 9 0 0 0 10 0 0 0 11 0 0 0 12 0 0 0 13 0 0 0 14 0 0 0 15 0 0 0 16 0 0 0 17 0 0 0 18 0 0 0 19 0 0 0 20 0 0 TM CM 0 NM 0 0 0 131 APPENDIX 2D – TABLE OF MANUAL HANDLING ESTIMATED TIMES 132 APPENDIX 2E – TABLE OF MANUAL INSERTION ESTIMATED TIMES 133 APPENDIX 2F – TABLE OF COMPATIBILITY BETWEEN PROCESSES AND MATERIALS 134 APPENDIX 2G – TABLE OF SHAPE GENERATION CAPABILITIES OF PROCESSES Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Wiper Holder Female Adjuster Knob Male Adjuster Stopper Rod A Rod B Snap Fit Shaft 1 Snap Fit Shaft 2 Snap Fit Shaft 3 Handle Pusher Joint No Yes No No No No Yes No Yes Yes Yes Yes Yes UniWall Yes B. Durability (Plastic part) Material requirement : A. Excellent Corrosion (Metal part) Depress Yes Name of component Connector No Yes No No No No No No Yes Yes Yes No No UniSect No No Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes AxisRot No No No Yes Yes Yes No Yes Yes No No No Yes Yes RegXSec No No No No No No No No No No No No No Yes CaptCav No No No No No No No No No No No No No No Enclosed No APPENDIX 7A - PART ATTRIBUTES OF EACH PART FOR NEW DESIGN OF SPONGE MOP Yes Yes Yes Yes Yes No No No Yes Yes No No No NoDraft No 135 136 APPENDIX 7B – TABLE OF PRIMARY PROCESS SELECTION FOR NEW DESIGN No. Name of Component Process 1 Connector Injection Molding 2 Wiper Holder Injection Molding 3 Female Adjuster Injection Molding 4 Knob Injection Molding 5 Male Adjuster Injection Molding 6 Stopper Injection Molding 7 Rod A Hot Extrusion 8 Rod B Hot Extrusion 9 Snap Fit Shaft 1 Powder Metal Part 10 Snap Fit Shaft 2 Powder Metal Part 11 Snap Fit Shaft 3 Powder Metal Part 12 Handle Injection Molding 13 Pusher Powder Metal Part 14 Joint Injection Molding 137 APPENDIX 7B – TABLE OF MATERIAL SELECTION FOR NEW DESIGN No. Name of Component Material 1 Connector Polypropylene 2 Wiper Holder Polypropylene 3 Female Adjuster Polypropylene 4 Knob Polypropylene 5 Male Adjuster Polypropylene 6 Stopper Polypropylene 7 Rod A Aluminum 8 Rod B Aluminum 9 Snap Fit Shaft 1 Stainless Steel 10 Snap Fit Shaft 2 Stainless Steel 11 Snap Fit Shaft 3 Stainless Steel 12 Handle Polypropylene 13 Pusher Stainless Steel 14 Joint Stainless Steel Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Wiper Holder Female Adjuster Knob Male Adjuster Stopper Rod A Rod B Snap Fit Shaft 2 Snap Fit Shaft 3 Handle Pusher Joint Yes Yes No No No Yes No Yes Yes Yes Yes Yes UniWall Yes B. Durability (Plastic part) Material requirement : A. Excellent Corrosion (Metal part) Depress Yes Name of component Connector No Yes No No No No No Yes Yes Yes No No UniSect No No Yes Yes Yes No Yes Yes Yes Yes No Yes Yes AxisRot No No No Yes Yes No Yes Yes No No No Yes Yes RegXSec No No No No No No No No No No No No Yes CaptCav No No No No No No No No No No No No No Enclosed No Yes Yes Yes Yes No No No Yes Yes No No No NoDraft No APPENDIX 7C - PART ATTRIBUTES OF EACH PART FOR NEW DESIGN OF SPONGE MOP BY TRIZ CONCEPT. 138 139 APPENDIX 7D – TABLE OF PRIMARY PROCESS SELECTION FOR NEW DESIGN BY TRIZ CONCEPT No. Name of Component Process 1 Connector Injection Molding 2 Wiper Holder Injection Molding 3 Female Adjuster Injection Molding 4 Knob Injection Molding 5 Male Adjuster Injection Molding 6 Stopper Injection Molding 7 Rod A Hot Extrusion 8 Rod B Hot Extrusion 9 Snap Fit Shaft 2 Powder Metal Part 10 Snap Fit Shaft 3 Powder Metal Part 11 Handle Injection Molding 12 Pusher Powder Metal Part 13 Joint Powder Metal Part 140 APPENDIX 7D – TABLE OF MATERIAL SELECTION FOR NEW DESIGN BY TRIZ CONCEPT No. Name of Component Material 1 Connector Polypropylene 2 Wiper Holder Polypropylene 3 Female Adjuster Polypropylene 4 Knob Polypropylene 5 Male Adjuster Polypropylene 6 Stopper Polypropylene 7 Rod A Aluminum 8 Rod B Aluminum 9 Snap Fit Shaft 2 Stainless Steel 10 Snap Fit Shaft 3 Stainless Steel 11 Handle Polypropylene 12 Pusher Stainless Steel 13 Joint Stainless Steel