Engineering Design of a mechanism Module code 4ME708 Module title ENGINEERING DESIGN AND WORKSHOP TECHNOLOGY (MC) Programme ΜEng (Hons) Mechanical Engineering and Design Programme code: H303 Module leader/ Assignment tutor: Alexandros Siasos Student Name: Meletis Korres Assignment number: 1 Weighting: 60% 0 ENGINEERING SCHOOL Submission instructions Cover sheet to be attached to the front of the assignment Question paper to be attached to assignment All pages to be numbered sequentially Module code 4ME708 Module title ENGINEERING DESIGN AND WORKSHOP TECHNOLOGY (MC) Programme ΜEng (Hons) Mechanical Engineering and Design Programme code H303 Module leader/ Assignment Alexandros Siasos tutor e-mail: a.siasos@medcollege.edu.gr Assignment title Engineering Design of a Mechanism Assignment number 1 Weighting 60% Handout date 21/02/2023 Submission date Learning 31/03/2023 outcomes assessed by this assignment Learning outcomes: 1, 2, 3 1 (see module guide) Introduction Engineering Design and Workshop Technology skills are considered to be of high importance for the modern engineers. The module in scope aims to the understanding of the procedures that have to be followed during the development stages of a new product. Thus, given specific customer requirements, students will be given the opportunity to develop and built a new product. Students will be assesed through two written asignments that are to cover the procedure of product design and manufacturing of a mechanical assembly. Also, manufacturing skills will be taken in consideration as workshop equipment will be used for the prototyping of the developed product. The present assessement sheet covers the following learning outcomes: Develop a design specification that establishes customer requirements. Develop and understand a design report with design concept, evaluation of concepts and selection of optimum design solution. Utilise and use computer technologies in the design process. Thus, students will be given a specific set of customer requirements and appropriate actions should be taken in order to carry out the procedure of Engineering Design of a product that covers the given requirements. At the end, an Engineering Report has to be given in order to describe the actions that have been taken in order to overcome the intermediate stages of Engineering Design. Also, detailed Engineering Drawings will be included at the Engineering Report. The Engineering Report should have a length of 1500-2000 words. Engineering Design Scenario and Initial Customer Requirements Your customer, a watchmaker’s tools manufacturer asks you to design a watch case vice that is to be adjustable and capable of gripping all common sizes of watch cases. The vice should be able to hold the watch cases without scratching them or deforming them. Also, the vice is intented to be used both as a handheld vice or mounted on the workbench. 2 (Note that this product is shown just for reference. Your vice should respect the given specifications) Your customer‘s manufacturing capabilities include injection molding of polymer parts, machining and precision ginding. You are alowed to design anything you want as long as the designed vice can be manufactured in-house. Also, you should consider designing the vice respecting the manufacturing related issues involved in the economic mass production of the designed products. Assignment Key Points Students should consider the following key points so as to fulfill assignment requirements. Market Research Taking in consideration the given customer requirements, students should perform a market research along with a competition analysis. This procedure is to extend the customer requirements and determine the basic features that lead to justification of the product. Design Specifications A design specification (DS) is created to ensure that the subsequent design and development of a product meets the needs of the user and also ensure the function a product is designed to perform. The DS report should show student understanding and appreciation of the DS document. Students need to use relevant details of customer requirements such as aesthetics, functions, performance, cost, and production parameters to identify the design parameters with the level of risk involved. Using the DS document, conceptual design solutions can be produced and evaluated to select the optimum design solution. Using the customer requirements students must develop a written specification considering all the relative and important factors. Concept Designs This stage of the design involves drawing up a number of different viable concept designs which satisfy the requirements of the product outlined in the DS and then evaluating them to decide on the most suitable one in order to develop further. Hence, concept design can be seen as a two-stage process of generation and evaluation. Final Design Drawings The chosen concept should be developed utilising computer technologies and detailed manufacturing drawings should be exported. The generated mechanical drawings have to fully define the digital prototype. Also CAD files of the solid models and 2D drawings must be submited. Marking Criteria The marking of this assessment will be based on the following requirements: 3 Presentation Including structure of report, contents page, brief, introduction, references and appendices. 10% Market Research Including existing products, competitors chart, market survey, analysis of results leading to 20% justification of the product. Design Specifications Including structure, relevance and accuracy of information in relation to specific products. 25% Concepts Including the drawing up of a number of different concepts and then evaluating them to decide 25% on the most suitable one. Detailed Design Including final design CAD files and complete sketches with dimensions Total 20% 100% Reading Materials Module lecture and support notes Antoniadis, A.Th., (2012) Manufacturing Technology: forming processes, Thessaloniki: Tziola Petropoulos , P. G., (1992) Manufacturing Technology, Thessaloniki :Ziti Mpouzakis, K.D., (2003) Principles of Mechanical Engineering Drawing, Thessaloniki: Ziti, Voulgaris, M., (2004) Mechanical Engineering Drawing, Athens: Synchroni Ekdotiki , Leake, J, M. (2008) Engineering design graphics: sketching, modelling, and visualization, New York: John Wiley & Sons. Cross, N. (2008) Engineering design methods: strategies for product design, 4th ed; Chichester: John Wiley. Pahl, G. (2007) Engineering design: A Systematic Approach, 3rd ed.; London: Springer. Baxter, M. (2002) Product design: a practical guide to systematic methods of new product development, Cheltenham: Nelson Thornes. Foley, van Dam, Feiner & Hughes. (1996) Computer graphics: principles and practice, 2nd ed; Reading, Mass; Wokingham: Addison-Wesley. French, M. J. (1985) Conceptual design for engineers, London: Berlin: Design Council. Hurst, K. (1999) Engineering design principles, London: Arnold. Raghavendra, N. V. , Krishnamurthy, L. (2015) Engineering metrology and measurements, 3rd ed; Chennai: Oxford University Press Bucher, J. L., (2015), The metrology handbook, 2nd ed; Winsconsin: ASQ Curtis, M., Farago, F. (2014), Handbook of Dimensional Measurement, 5th ed; South Norwalk: Industrial Press, Inc. 4 Note: These sources are guides only to commonly available material. Students will also be expected to consult other relevant source material according to the nature of the project. Late Submission There are no automatic rights to late submission, with a capped mark of 40%. However, the University acknowledges that there may be circumstances which prevent students from meeting deadlines. There are now three distinct processes in place to deal with differing student circumstances: Assessed Extended Deadline (AED) Students with disabilities or long term health issues are entitled to a Support Plan. The Support Plan will outline any adjustments to assessments which are required to accommodate an individual student’s needs. For further details refer to the link below: http://www.derby.ac.uk/studentatozHE/support-plans Exceptional Extenuating Circumstances (EEC) The EEC policy applies to situations where serious, unforeseen circumstances prevent the student from completing the assignment on time or to the normal standard. Students who submit a successful EEC claim will usually be required to complete a different assessment to that which was originally set. All EEC claims will be considered by Faculty/UDC panels, which will convene on a monthly basis. For further details refer to the link below: http://www.derby.ac.uk/eec Late Submission up to One Week Covering unexpected and severe disruption to study, where circumstances do not require the additional time allowed for by an EEC, the Late Submission process enables students to complete their existing assessment up to one week late, without a cap on the grade. Requests for late submission will be made to the relevant Subject Manager in the School who can authorise an extension of up to a maximum of one week. The Subject Manager will expect to see compelling evidence that such an extension is appropriate. Academic Offences An "academic offence" has been committed when a student tries to gain improper advantage for her/himself by breaking, or not following, the Academic Regulations concerning any part of the assessment process. This procedure applies to all students engaged in any University assessment activity whether on or off site including collaborative programmes. 5 Please be aware that should the marking reveal the possibility that the work submitted is not that of the student, then a verbal examination (VIVA) and interview will be conducted to ascertain the validity of the work. Assessment Declarations This is an individual not a group project. Each student will submit their own set of 3D Models, Engineering Drawings and Engineering Report. It is acceptable and advisable to discuss their progress with other students but do not copy their files or ideas as that could be considered as plagiarism. Virtual Prototypes (i.e. 3D Models), Engineering Drawings and the Engineering Report should be submitted in electronic format. Also, Engineering Drawings should be exported and submitted in .pdf format as an equivalent to the printing in scale procedure. Performance Criteria According to the following marking scale, a mark of 40% is required as a minimum pass for this assessment. % mark These are typical characteristics of the quality of work associated with each grade. The descriptors are illustrative only and for guidance only. They are not comprehensive. 70-100% Category Grade Descriptors Excellent Outstanding; all assignment topics are thoroughly analysed and explained; product planning procedure has been clearly stated; solution variants have been evaluated according to the most crucial criteria regarding the application; product proposal is been successfully created; technical report is characterised by excellent coherence and logic, high quality presentation and exceptional clarity of ideas. Trivial or very minor errors. Very good A very good standard; all assignment topics are covered; product planning procedure is clearly stated; solution variants have been evaluated according to basic criteria regarding the application; product proposal is original and covers customer requirements; engineering drawings have been created; technical report is characterised by very good sense of coherence and logic, thoughtful and effective presentation and pleasing clarity of ideas. Minor errors only. Merit 60-69% Distinction original, innovative and covers customer requirements; engineering drawings have 6 50-59% Good A good standard; most assignment topics are covered; product planning procedure has been followed; solution variants have been created and evaluated; product proposal covers customer requirements; basic engineering drawings have been created; technical report is characterised by ideas generally clear and coherent, a good standard of presentation. Some evidence of misunderstandings and some deficiencies in presentation. 40-49% Satisfactory A sound standard of work; basic assignment topics are covered; product planning procedure has been followed; solution variants have been created and evaluated; product proposal fairly covers customer requirements; some engineering drawings coherent, a good standard of presentation. Some significant misunderstandings or errors and weakness in style or presentation but satisfactory overall. 35-39% Pass have been created; technical report is characterised by ideas generally clear and Unsatisfactory Overall marginally unsatisfactory; some sound aspects but some of the following weaknesses are evident; product proposal marginally covers customer originality; not well researched; standard of presentation unacceptable; ideas unclear and incoherent; some significant errors and misunderstandings. Marginal fail. 1-34% Marginal Fail requirements; inadequate critical analysis and evaluation; little evidence of Very poor Well below the pass standard; product proposal does not cover customer requirements; a poor critical analysis and evaluation; no evidence of originality; poorly researched; standard of presentation totally unacceptable; ideas confused and incoherent, some serious misunderstandings and errors. A clear fail well short Fail of the pass standard. NS Non-submission No work has been submitted. Z Academic offence notation Applies to proven instances of academic offence. 7 Contents 1 Introduction .............................................................................................................9 2 Task Clarification: ....................................................................................................9 2.1 Customer requirements: ...................................................................................9 2.2 Market Research: .............................................................................................9 2.3 Personal requirements: ..................................................................................12 2.4 Final Design specification sheet: ....................................................................13 3 Conceptual & embodiment design: ........................................................................14 4 Evaluation .............................................................................................................17 4.1 Definition of criteria: .......................................................................................17 4.1.1 Manufacturing criteria: ................................................................................17 4.1.2 User criteria: ...............................................................................................17 4.2 Weights and values of criteria: .......................................................................18 4.3 Evaluation process: ........................................................................................19 4.4 Final evaluation: .............................................................................................20 5 Detailed design: ....................................................................................................21 5.1 3D CAD: .........................................................................................................21 5.2 2D Engineering Drawings: ..............................................................................21 6 Outro: ....................................................................................................................22 Figure 1 Metallic watch case vice ..........................Ошибка! Закладка не определена. Figure 2 Plastic watch case vice ............................Ошибка! Закладка не определена. Figure 3 Watch case vice with no pins ...........................................................................11 Figure 4 Four screw vice ...............................................................................................11 Figure 5 Two screw vice ................................................................................................12 Figure 6 Design 1 ..........................................................................................................14 Figure 7 Design 2 ..........................................................................................................14 Figure 8 Design 3 ..........................................................................................................15 Figure 9 Design 4 ..........................................................................................................15 Figure 10 Design 5 ........................................................................................................16 Figure 11 3-D design in SolidWorks ..............................................................................21 Figure 12 2-D design in SolidWorks ..............................................................................21 8 1 Introduction In this assignment we are tasked with creating a watch vice that adheres to specific requirements and using specific manufacturing techniques that the customer has available in-house. The customer is planning to sell his product to professional watchmakers with that in mind we will need a product that is robust and able to be used for long periods of time without it breaking down. 2 Task Clarification: 2.1 Customer requirements: The requirements given to us by the customer are the following: The watch case vice has to be adjustable and capable of gripping all common sizes of watch cases The vice should be able to hold the watch cases without scratching them or deforming them The vice is indented to be used both as a handheld vice or mounted on the workbench It should also be manufactured using only the following processes injection molding, machining and precision grinding It should be able to be manufactured at scale easily 2.2 Market Research: According to the market research the main things watchmakers and amateur watchmakers look for in a watch vice are customization versatility durability aesthetics. The following companies are some of the major players in the watch vice market and their product offerings as well as their dimensions: Bergeon is a Swiss company that produces high-quality watchmaking tools, including watch vices. Their products are known for their durability and precision. Horotec is a Swiss company that specializes in producing watchmaking tools, including watch vices. Their products are known for their versatility and customization options. 9 Figure 2 Plastic watch case vice The watch vice depicted above is made out of plastic and metal. There are two metal rods used as guides and a metal screw with a spring in the middle for adjusting the length between the two parts. The use of the spring serves several purposes it helps to apply pressure evenly across the vice jaws, which prevent the part from slipping or moving during the repair process. Furthermore the spring allows the user to apply a controlled amount of pressure to the watch part being held which can be especially important when working with delicate or fragile components. Finally the spring helps to keep the screw in place once it has been adjusted maintining the desired jaw width. The screw head is textured giving it increased grip to allow the user to use it even in situations where their hands are wet or oily. The pegs are made out of Nylon and are the elements that hold the watch case in place. It can be used both handheld and laid on top of a workbench. Figure 1 Metallic watch case vice The above watch vice is similar to the previous one with three major changes firstly the spring is no longer present secondly the plastic has been replaced by aluminum and thirdly 10 there are more holes for the pegs to go into allowing for a greater variation of watches to be held by the vice. Figure 3 Watch case vice with no pins The above vice is a simplification of the previous vices making it more limited in its function but also cheaper to manufacture. The main negative part of this vice is that the watch case is being held directly by metal which could damage or scrach the case being held. Figure 4 Four screw vice The above vice is a variation on the previous vices with the same underlying principles involved but instead of one screw there are four controlling each individual peg. The main disadvantage is that it can be tedious having to screw four screws to get the watch case to sit in the middle of the vice 11 Figure 5 Two screw vice The above vice improves on the previous one by reducing the number of screws you have to turn to lock in the watch by making each screw operate two of the pegs this adds a bit of additional height and weight and it could be difficult to hold because of these increases. 2.3 Personal requirements: Have a stable base that will keep it in place while working on the watch and should not move or wobble during use. Should be easy to use and should not require specialized tools for its operation. Should use high quality materials to be able to last for a long time. It should be reasonably priced to be competitive in the market. Should be able to be used easily with other machines in the shop such as presses without needing to remove the case from the watch vice. 12 2.4 Final Design specification sheet: Demands The watch case vice has to be adjustable and capable of gripping all common sizes of watch cases The vice should be able to hold the watch cases without scratching them or deforming them The vice is indented to be used both as a handheld vice or mounted on the workbench It should also be manufactured using only the following processes injection molding, machining and precision grinding It should be able to be manufactured at scale easily Wishes Have a stable base that will keep it in place while working on the watch and should not move or wobble during use. Should be easy to use and should not require specialized tools for its operation. Should use high quality materials to be able to last for a long time. It should be reasonably prices as to be competitive in the market. Should be able to be used easily with other machines in the shop such as presses without needing to remove the case from the watch vice. Should be light weight enough to allow the user to hold it by hand for extended periods of time 13 3 Conceptual & embodiment design: Figure 6 Design 1 The above vice works similar to the first and second vice mentioned in market research. This design can be manufactured both from plastic and metal depending on the price point we aim to achieve and satisfies the requirements set out by the client as well as our personal wishes. It works by rotating a single screw to tighten the watch in place and uses plastic pegs to hold the watch allowing it to handle it without it being scratched. Furthermore, the pegs are modular to allow for the handling of all common watch cases and possibly exotic sizes and designs as well. Figure 7 Design 2 The above design has the same underlying working mechanism as the first a single screw providing tension so that the watch case can be held in place but loses its modularity by not using pegs to hold the watch. This also reduces weight and makes manufacturing the piece easier having less pieces. The main drawback of this design is its lack of modularity (can’t hold watches with weird shapes) and the chance that the vice could scratch the watch depending on the material of both the vice and the watch. 14 Figure 8 Design 3 The above vice works by using four pegs to keep the watch in place its main advantages are that it is easy to manufacture and use and has no moving parts. Its main disadvantages are that it could be heavier than intended depending on the height of the plate. Because there is no tension problems could arise on gripping the watch securely. Furthermore, depending on the material used to manufacture it, it could scratch the watch case as well as the watch dial during use due to it being in direct contact with the surface of the plate. Figure 9 Design 4 The above design is a variation of the first design in a sense instead of a single threaded screw providing tension to the piece this design uses two. This increase gives more modularity to the amount of watch cases this particular vice can accommodate but what it gains in modularity loses in ease of use and complexity of manufacturing. This can also increase the weight, the life cycle of the vice since there are more points of failure and its ease of use. Furthermore, problems could arise with the scratching of the dial and frame of a watch due to the direct contact that it has with the top plate of the vice. 15 Figure 10 Design 5 The final design is similar to the previous one using the same underlying structure to provide tension to the watch but having four screws instead of two. Furthermore, it provides almost the identical upsides and downsides of the previous watch vice, mainly it has increased modularity with the ability to secure in place all sizes of watch cases. But with that increase in modularity come the increase in complexity of manufacturing and use while also increasing the potential points of failure by increasing its moving parts. 16 4 Evaluation 4.1 Definition of criteria: 4.1.1 Manufacturing criteria: Manufacturability: How complex is the material to manufacture as well as time complexity. Higher complexity equals higher cost. Assembly complexity Difficulty in assembling the different pieces of material Material availability How difficult is to source the material in Greece in the required quantities Production scalability How easily is it to scale up or down production of the product Quality Control difficulty How difficult is it to test that a product is within the given specification and how time consuming the process is. Manufacturability cost Overall cost to manufacture the product and margins related to selling it. 4.1.2 User criteria: Weight: The weight dictates how easy it is to hold. Lighter means better Watch compatibility Is the vice going to be compatible with weird shapes of watches as well as all standard sizes Stability How stable is it when it is on a bench and used with auxiliary machinery. Higher stability is better Durability How difficult is it to break the watch case holder how easily can it be repaired Ease of use How easily can it be operated by a non-trained person Ergonomics How easy is it to work on a watch while holding it how easy is it to work on a watch while the vice is on the table. Stability of the watch How stable is the watch during transport or during movement. during movement Adjustability How adjustable is it to allow the user to work from different angles without impending their work Compatibility with How compatible is it with other machines that the user might other machines use in conjunction with the vice. 17 4.2 Weights and values of criteria: Here we will use the method named Weighted Factor Scoring Model to evaluate the designs and find which one is the best according to our manufacturing criteria and user criteria. The total of the weight factors should equal to one (1). Manufacturability 0.05 Assembly complexity 0.05 Material availability 0.04 Production scalability 0.05 Quality control difficulty 0.03 Manufacturability cost 0.05 Weight 0.07 Watch compatibility 0.10 Stability 0.10 Durability 0.07 Ease of use 0.09 Ergonomics 0.05 Stability of the watch during movement 0.05 Adjustability 0.08 Compatibility with other machines 0.12 Sum: 1.00 The weights were chosen in such a way such that it prioritizes the feel and usability for the end user more than the manufacturing complexity. The reason being that because this item is marketed towards professionals, they care more about the usability and long lastingness of the product rather than the price. For example, a weight of 0.12 was chosen for compatibility with other machines because it is of critical importance for the end user to be able to seamlessly transition from working on a watch to closing/opening the case for example without him needing to remove the watch case from one vice and put it in another. Furthermore, the following values were picked for watch compatibility (0.10), stability (0.10), ease of use (0.09), adjustability (0.08), weight (0.07). The reason these values were picked was because its important for the end user to be able to easily work long hours with the product without them getting tired. On the other hand, on the manufacturability side weights were give <=0.05 because as mentioned the end user cares more about the user experience than incurring a higher cost for the product. 18 Next the values and explanation for each value that can be inserted is given: Value: Explanation: 0 Insufficient coverage of the criteria 1 Tolerable coverage of the criteria 2 Sufficient coverage of the criteria 3 Good coverage of the criteria 4 Excellent coverage of the criteria 4.3 Evaluation process: Criteria Design Evaluation Weighted evaluation of the designs Weight Design Design Design Design Design Design Design Design Design Design 1 2 3 4 5 1 2 3 4 5 Manufacturability 0.05 4 4 4 2 1 0.2 0.2 0.2 0.1 0.05 Assembly complexity 0.05 3 3 4 2 1 0.15 0.15 0.2 0.1 0.05 Material availability 0.04 4 4 4 4 4 0.16 0.16 0.16 0.16 0.16 Production scalability 0.05 4 4 4 3 2 0.2 0.2 0.2 0.15 0.1 0.03 4 4 4 3 2 0.12 0.12 0.12 0.09 0.06 0.05 4 4 4 3 2 0.2 0.2 0.2 0.15 0.1 Weight 0.07 3 3 2 2 2 0.21 0.21 0.14 0.14 0.14 Watch compatibility 0.1 3 2 3 4 4 0.3 0.2 0.3 0.4 0.4 Stability 0.1 4 2 1 3 3 0.4 0.2 0.1 0.3 0.3 Durability 0.07 4 4 4 4 4 0.28 0.28 0.28 0.28 0.28 Ease of use 0.09 4 4 4 3 2 0.36 0.36 0.36 0.27 0.18 Ergonomics 0.05 3 2 2 3 3 0.15 0.1 0.1 0.15 0.15 Stability of the watch during movement 0.05 4 3 0 4 4 0.2 0.15 0 0.2 0.2 Adjustability 0.08 2 2 2 3 4 0.16 0.16 0.16 0.24 0.32 Compatibility with other machines 0.12 4 0 0 1 2 0.48 0 0 0.12 0.24 3.57 2.69 2.52 2.85 2.73 1 4 5 2 3 Quality control difficulty Manufacturability cost 1 Rank based on results 19 4.4 Final evaluation: Overall design 1 was the most balanced of the five where the manufacturability of it would be relatively easy while also maximizing the end user experience. Design number 2 and 3 focused more on being very easy to manufacture but losing out on the end user experience and the versatility of the product. Finally design number 4 and 5 were the most complex designs by a manufacturing point of view offering the most modularity and flexibility but were in fact so modular and flexible that it actually made the end user experience overly complicated which is why it lost to the first design. Another detrimental fact that caused this ranking is that because of their complexity and lots of moving parts design 4 and 5 where heavier than design number 1 and also less compatible with the rest of the machines due to their complicated design shape. Because design number one was both good in the manufacturability and end user experience it is the clear winner while the rest where only primarily good on one of them and lacking a bit on the other leading to them being close to each other in rankings. 20 5 Detailed design: Below the 3D render of the watch case holder can be seen it works by twisting the knob and rotating the screw (middle rod) to grip the watch case in place. It can fit all kinds of watches available and the pins provide some specific cut outs so the watch case can be better gripped in place. Furthermore, the pins are removable and each pin can be positioned in three distinct positions. Moreover, there is a filet on the outside of the part to ease manufacturing and make it more aesthetically pleasing. A cutout exists on the left and right sides of the part as to allow it to be mounted to rails in other tools that exist in the workshop. All of this can be seen in the 3D and 2D designs provided below 5.1 3D CAD: Figure 11 3-D design in SolidWorks 5.2 2D Engineering Drawings: Figure 12 2-D design in SolidWorks 21 6 Outro: In this assignment we went through the process of creating a watch case holder from start to finish for a customer. We went through the stages of task clarification, conceptual & embodiment design, and detailed design. In task clarification we understood the demands of the client, we did market research concerning the product, gave our own demands and wishes and finally created a design specification sheet. In the next step we moved over to conceptual and embodiment design we created some designs that could fulfill our design specification sheets demand and then evaluated each design based on a number of factors. Finally, we chose the design that got the highest rating and designed it in solid works so it is able to be manufactured. I think this was an interesting assignment that challenged us to put what we have learned in the past year into practice and give us a better idea what to expect to be doing in the future. 22