UNITEN
Dr. HABEEB HATTAB HABEEB
Office: BN-Block, Level-3, Room088
Email: hbuni61@yahoo.com
Ext. No.: 7292
Lecturer:
Dr.Nasional
HABEEB ALANI
University
TENAGA
TENAGA Nasional
Lecturer: Habeeb University
Al-Ani
UNITEN
University TENAGA National
College Of Engineering
Mechanical Department
Academic Year – 2008-2009
Lecture Note
Lecturer:
Dr.Nasional
HABEEB ALANI
University
TENAGA
TENAGA Nasional
Lecturer: HabeebUniversity
Al-Ani
UNITEN
Computer Aided Manufacturing
CAM
Lecturer:
Dr.Nasional
HABEEB ALANI
University
TENAGA
TENAGA Nasional
Lecturer: HabeebUniversity
Al-Ani
Computer Aided Process
Planning
(CAPP)
Process Planning
Principle activity of manufacturing engineering
includes
1. Deciding which process and methods to be
used in what sequence
2. Determining tooling requirements
3. Selecting production equipment and
systems
4. Estimating cost of production of selected
process, tooling, and equipment
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Computer Aided Process Planning (CAPP)
CAPP is an automated process planning, can
be divided into two main sytems
1. Retrieval Systems
2. Generative Systems
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Retrieval CAPP systems
Based on group technology (GT) and part classification
and coding a standard process plan is stored in
computer files for each part code number.
GT: Similar parts identified and grouped together in
order to take advantage of their similarities in
design and production.
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Generatival CAPP systems
Alternative to Retrieval systems. Rather than retrieving and
editing an existing plans from a data base, a generative
system creates the process plan using systematic
procedures that might be applied by a human planner.
In fully Generative CAPP system, a process sequence is
planned without human assistance and predefined
parts.
It is a branch of artificial inteligence “Expert Systems”.
Computer Programs are capable of solving complex
problems that normally requires a human.
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Generative CAPP systems (continue)
Several ingredients needed
1. Knowledge Base: Technical knowledge of manufacturing
and the logic used by a succesfull process planners must
be captured and coded into a computer program.
Generative CAPP systems use the knowledge base to
solve the process planning problems and to create “route
sheets”.
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Generative CAPP systems (continue)
2. Computer Compatible Part Description: Description
contains all the data needed to plan the process
sequence. For example
i.
Geometric model of the part developed on a CAD
system.
ii. Group technology code number of part defining its
significant features is given.
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Generative CAPP systems (continue)
3. Inference Engine: A generative CAPP system
requires the capability to apply the planning logic
and process knowledge contained in the knowledge
base to a given part description. CAPP applies its
knowledge base to solve a specific problem of
planning the process for a new part. This procedure
is called “Inference Engine”
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Benefits of CAPP systems
1. Process rationalization and standardization (logical
and consistent)
2. Increased productivity (greater number of process
plans to be developed)
3. Reduced lead time
4. Improved legibility
5. Interfacing with other programs (cost estimation,
etc..)
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Design for Manufacturing and Assembly (DFM/A)
To implement DFM/A, a company must make
changes in its organizaitonal structure and
design principles and guidelines.
1) Organizational changes need to be done to have
better intraction between design and MFG
personnel.
Organizational changes must contain :
a)Team formed of designer, manufacturing
engineers, quality engineers, material engineers..
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
(DFM/A)(cont.)
b)Designers must spend some time in
manufacturing area.
c)A manufacturing engineer should consult
the designers.
2) One of the guide lines in designing is to
make it as simple as possible, but in design
for assembly, additional features are
required, such as; to be technically good in
manufacturing, is it safe from copying( can
competitors learn the secrets of our
product by reverse engineering?).
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Benefits of DFM/A
1. Shorter time to bring product to the
market
2. Smoother transition into production
3. Fewer components in final product
4. Easier assembly
5. Lower cost of production
6. Higher product quality
7. Greater customer satisfaction
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Design for Quality (DFQ)
Traditional quality control has been concerned
with detecting the or quality in manufactured
products and taking corrective action to
eliminate it.
The modern view of quality control
encompasses a broader scope of activities
including robust design and statistical process
control.
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Design for Quality (DFQ)(continue)
Robust Design: Product’s function and
performance is not sensitive to the variations in
design and manufacturing parameters. It
involves the design of both the product and
process.
Statistical Process Control(SPC): Involving the
use of statistical methods to assess and analyze
the variations in process. This method includes
keeping records of production data and charts.
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Design for Life Cycle
Factors associated with life cycle
1)Delivery: Transport cost, delivery time, etc..
2)Installation: Utility requirements.
3)Reliable: Service life, failure rates, etc..
4)Maintaining: Design modularity, maintenance
requirements.
5)Service: Spare parts, field service.
6)Human factors: Complexity of controls, risks, etc..
7)Upgrading: Compatibility to the future designs.
8)Disposability: Recycling of components, waste
hazards, etc..
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Design for Cost
In manufacturing our main aim is to reduce the cost of
production. Of course we need to make the processes
easy and quality high. Choosing the best material and
manufacturing processes among all the available
materials and processes is a complex decision making.
In cost reducing there is two main factors
1) Role of materials
2) Role of manufacturing processes
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Role of Materials
Understand the functional requirements of each part,
choosing criteria will include
1) Mechanical properties of the material: Strength,
toughness, ductility, hardness, etc..
2) Physical properties of the material: Density,
melting point, thermal expansion, etc..
3) Chemical properties of the material: Oxidation,
corrosion, etc..
4) Shape of the material:Need to select the shape
with respect to the design, therefore it requires
less additional process.
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Role of Materials (continue)
5) Manufacturing properties of the material: Need to
select the suitable material for the process that is
going to be applied.
6) Material supply: Location of the plant, location of
the country, politics in the country affects the
availabitiy of the material. Therefore the cost.
7) Material cost: Cost of a raw materialdepends not
only on the material itself but also on its shape,
size and condition. Also, price of a material
decreases as the volume increases.Demand is
another aspect in the price of a material.
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Role of Materials (continue)
8) Product design: Cost of material is a significant
portion of product cost. This cost can be reduced
by optimization in design or reducing thickness.
But minimization in material thickness may cause
problems in manufacturing.
9) Substitution of materials: New products appear
continually in the market to substitude the
materials in use. The purpose of substitution is to
reduce the cost of the material, to improve
manufacturing and assembly, to reduce
maintenance, etc...
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Role of Manufacturing Processes
Proper selection of manufacturing processes and
machinery depends on various considerations like:
1)Properties of the work material
2)The shape and the size of the work material
3)Surface finish and dimensional tolerances
4)Quantity of the production
5)Functional requirements
6)Process capabilities.
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Manufacturing Cost
1) Material cost
2) Tooling cost
3) Fixed costs
4) Capital costs
5) Direct labor costs
6) Indirect labor costs
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Manufacturing Cost (continue)
Fixed costs:Electric, fuel, taxes, rent, insurance type of costs
called fixed costs. These costs are not sensitive to the
production volume.
Capital costs:Investment in land, building, machinery,tooling
and equipment.
Direct labor costs:Includes all labor, from the time raw
materials are first handled to the time when the product is
finisihed. This period is called as floor-to-floor time, and
the personnel is called productive labor.
Indirect labor costs:These costs are refered to as overhead
(burden rate) and charged proportionally to all products.
The personnel involved in activities such as quality control,
repair, maintenance, engineering, research, sales, etc
called non-productive labor creates these costs.
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Manufacturing Cost and Production Rate
Approximate cost division
Design
5%
Material
50%
Direct labor 15%
Overhead
30%
Of course the direct labor costs changes with respect to the
manufacturing volume. High volume type of manufacturing
includes dedicated machinery which needs less direct labor.
On the other hand small volume productions needs more direct
Labor since the machinery used is general purpose type of
Machines and needs more human interaction.
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Cost Reduction
Cost can be reduced by
• Simplifying part design
• Allowances of rougher surface finish and broader
tolerancing
• Using less expensive material
• Investigating the alternative ways of
manufacturing(see the figure next slide)
• Using efficent machinery
• Since manufacturing adds value to materials by
using value analysis methods we can reduce the
cost.
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Methods of Making a Part
Various methods of making a simple part:
(a) casting or powder metallurgy.
(b) forging or upsetting.
(c) extrusion.
(d) machining.
(e) joining two pieces.
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Value Analysis
Value analysis consists of six phases
• Information phase: gather data and determine
cost
• Analysis phase:Identify problems and
opportunities
• Creativity phase:Seek ideas to solve problems
• Evaluation phase: Select ideas and identify costs
involved.
• Implementation phase:Take necessary actions to
accomplish the task
• Review phase: Analyze to see if any adjustment is
needed
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional