1. MODULE 1
COURSE OUTCOMES
Different mfg processes
Design for mfg
Selection of materials for mfg processes
Selection of mfg process
Production systems
Product quality
Economics of mfging on mfg processes
2. Introduction to Mfg
MFG : Converting raw material into finished product.
• Some products are a single components
(nail, bolt, fork, coat hanger, etc.)
• Some products are assemblies of many
components (ball point pens,
automobiles, washing machines, etc.)
9. DFM
Design for manufacturability (also known as design for manufacturing)- is
the art of designing products in such a way that they are easy to
manufacture.
Each part or component of a product must be designed so that it not only
meets design requirements & specifications but can also be mfged
economically and with relative ease.
This approach improves productivity and allows a manufacturer to remain
competitive.
DFM integrates product design process with materials, manufacturing
methods, process planning, assembly, testing, and quality assurance.
10. What Internal Organization has the most
Influence over Price, Quality, & Cycle Time?
Manufacturing
20 - 30%
Design
70 - 80%
11. Design for Mfg Guidelines
1. Minimize Total Number of Parts
2. Develop a Modular Design
3. Minimize Part Variations
4. Design Parts to be Multifunctional
5. Design Parts for Multiuse
6. Design Parts for Ease of Fabrication
7. Avoid Separate Fasteners
12. Design for Mfg Guidelines (Cont.)
8. Minimize Assembly Direction (Top Down
Direction Preferred)
9. Maximize Compliance in Assembly
10. Minimize Handling in Assembly
11. Minimize complexity of Design
12. Maximize common Jigs and Fixtures
13. Optimize Work Position
14. Ease Access
13. Manufacturing a Product:
General Considerations
• Material Selection
• Processing Methods
• Final Shape and Appearance
• Dimensional and Surface Finish
• Economics of Tooling
• Design Requirements
• Safety and Environmental Concerns
15. Selecting Materials for Products
Selection of materials for products requires
much experience, but several databases and
expert systems are now available
The following are the factors in selection of materials for
products :
1. Material Substitution
2. Material Properties
3. Cost and Availability
4. Service Life and Recycling
16. Material substitution
Majority of the design and mfging activities are
concerned with improving existing products
Reasons for substituting materials are:
1. Reduce the costs of materials and processing
2. Improve mfging, assembly, and installation
3. Improve the performance of the product
4. Increase stiffness-to-weight and strength-to-weight
ratios
5. Reduce the need for maintenance and repair
6. Reduce vulnerability to the unreliability of the
supply of materials
7. Improve compliance with legislation and
regulations
17. Material Substitution
Substitution of Materials in the Automobile
Industry
• Automobile industry is a major consumer of
both metallic & nonmetallic materials
• Constant competition among suppliers,
particularly in steel, aluminum, and plastics
• Efforts in investigating the advantages and
limitations of principal materials
18. Material Substitution
Substitution of Materials in the Aircraft and Aerospace Industries
• Advanced materials are used in the Lockheed
C-5A transport aircraft
19. Material Substitution
Material Substitution in Common Products
• Available products can be made by either set
of materials:
1. Metal vs. wooden baseball bat
2. Metal vs. reinforced-plastic or wood handle for
a hammer
3. Plastic vs. metal intake manifold
4. Cast-iron vs. aluminium lawn chair
5. Plastic vs. sheet-metal light-switch plate
20. Material Substitution
Material Changes between C-5A and C-5B Military Cargo Aircraft
• Table shows the changes made in materials for
components of the two aircraft listed and the
reasons for the changes
21. Properties of Materials
Mechanical Properties: strength, toughness, ductility,
hardness, elasticity, fatigue, creep.
Behavior Under Loading: tension, compression,
bending, torsion, shear.
Physical Properties: density, specific heat, thermal
expansion, thermal conductivity, melting point, electrical
and magnetic properties.
Chemical Properties: oxidation, corrosion, degradation,
toxicity, flammability.
25. The Choice ………
In many cases metals and non metals are viewed as
competing materials
The selection is being based on how well each is
capable of providing the required properties
When both perform adequately total cost often
becomes the deciding factor
1. The cost of material
2. Plus the cost of fabricating the desired component
26. Ferrous Metals: Applications
• Structural: building structures, concrete
reinforcement
• Automotive: chassis, engine parts, drive train, body
parts
• Marine: ship hulls, structure, engines
• Defense: tanks, weapons
• Consumer Products: appliances, recreational
vehicles, toys, utensils and tools
28. Plastics (Polymers)
• Compared to metals, plastics have lower
density, strength, elastic modulus, and thermal
and electrical conductivity, and a higher
coefficient of thermal expansion
• The design of plastic parts should include
considerations of their low strength and
stiffness, and high thermal expansion and low
resistance to temperature.
30. Cost and Availability
Cost and availably of raw matl/processed matls are
major concern in mfg.
If raw/ processed materials are not commercially
available in the desired shape, dimensions,
tolerance, & quantities substitutes or additional
processing may be required; which will increase
production cost.
31. Service Life and Recycling
Wear, fatigue ,creep and dimensional
stability are important considerations.
Recycling or proper method of disposal of
the components
The proper treatment and disposal of
toxic wastes
32. Selecting Manufacturing Processes
Processing methods for materials can be listed as
follows:
1. Casting
2. Forming and shaping
3. Machining
4. Joining
5. Micro manufacturing and nanomanufacturing
6. Finishing
33. Selecting Manufacturing Process
A wide range of mfg process are used to produce a
variety of parts, shapes and sizes.
There is usually more than one method of mfg a
part from a given material.
Part shape, size, and thickness, dimensional
tolerances, and surface-finish requirements greatly
influence the selection of a process
Quantity of parts and production rates determine
the processes that are used and the economics of
production.
34. Function dictates the
Shape restricts
choice of material and
the choice of
shape.
Function material and
process.
Material Shape
Process is Process interacts
Process
influenced by
with shape.
material
Material selection and process cannot be separated from the
shape and the function of the product, two way interaction.
35. Various methods of making a simple part: (a) casting or powder metallurgy, (b) forging
or upsetting, (c) extrusion, (d) machining, (e) joining two pieces.
36. Manufacturing a Sheet-metal Part by Different Methods
• Two methods of making a dish-shaped sheet
metal part:
(a) press working
(b) explosive forming
38. ADVANTAGES OF CASTING PROCESS
The most intricate of shapes, both external and internal, may
be cast. As a result, many other operations, such as
machining, forging, and welding, can be minimized or
eliminated.
Because of their physical properties, some metals can only be
cast to shape since they cannot be hot-worked into bars,
rods, plates, or other shapes.
Objects may be cast in a single piece.
Metal casting is a process highly adaptable to the
requirements of mass production.
39. Large numbers of a given casting may be produced very
rapidly.
For example, in the automotive industry hundreds of
thousands of cast engine blocks and transmission cases are
produced each year.
Extremely large, heavy metal objects may be cast when they
would be difficult or economically impossible to produce
otherwise.
Large pump housing, valves, and hydroelectric plant parts
weighing up to 200 tons illustrate this advantage of the
casting process.
40. Some engineering properties are obtained more favorably in
cast metals. Examples are :: More uniform properties
from a directional standpoint; i.e., cast metals exhibit
the same properties regardless of which direction is
selected for the test piece relative to the original
casting.
Strength and lightness in certain light metal alloys, which
can be produced only as castings.
Good bearing qualities are obtained in casting metals.
41. Disadvantages of Casting:
Though casting is cheapest for MASS Production, it becomes
non economical in case of JOB production.
Sand casting leaves rough surface which needs machining in
most of cases. It adds up the cost in production.
Again in sand casting, poor dimensional accuracy is achieved.
Cast products are superior for compressive loads but they are
very poor in tensile or shock loads.(They are brittle).
42. Advantages of Forging
The forgings are consistent in shape and do not have
any voids, porosity, inclusions, or defects.
Parts that are produced by this method have high
strength to weight ratio and therefore used in the
design of the aircraft frames.
It offers low cost for moderate to long runs.
• High speed of production.
DISADVANTAGES
High tool cost.
High tool maintenance.
Limitation in size and shape.
43. Production Methods
• Job Production – One-off production - each item
might have particular specifications
• Mass Production – suitable for mass market
products that are identical
• Batch Production – each stage of the production
process has an operation completed on it before
moving on to the next stage – allows
modifications to be made to products that
otherwise are the same
44. Manufacturing Costs and Cost Reduction
• The total cost of a product consists of material
costs, tooling costs, fixed costs, variable costs,
direct-labor costs, and indirect-labor costs
• Depending on the particular company and the
type of products made, different methods of cost
accounting may be used
• Costs are also attributed directly to product
liability
45. Manufacturing Costs and Cost Reduction
Materials Costs
• Costs depend on the type of material, processing
history, size, shape, and surface characteristics
Tooling Costs
• Costs are involved in making the tools, dies,
molds, patterns, and special jigs and fixtures
required for manufacturing a product
• Greatly influenced by the production process
selected
46. Manufacturing Costs and Cost Reduction
Fixed Costs
• These costs include electric power,
fuel, taxes on real estate, rent,
insurance, and capital
Capital Costs
• Represent machinery, tooling,
equipment, and investment in
buildings and land
47. Manufacturing Costs and Cost Reduction
Direct-labor Costs
• Costs for labor that is directly involved in
manufacturing products
• Time required for producing a part depends on its
size, shape, dimensional accuracy and surface finish
• Labor costs in manufacturing and assembly vary
greatly from country to country
• Manufacturers consider moving production to
countries with a lower labor rate known as
outsourcing
48. Manufacturing Costs and Cost Reduction
Indirect-labor Costs
• Consist of costs for supervision, maintenance,
quality control, repair, engineering, research, and
sales and cost of office staff
Manufacturing Costs and Production Quantity
• Large production require the use of mass-
production special machinery (dedicated
machinery)
• Small-batch production involves general-purpose
machines
49. Manufacturing Costs and Cost Reduction
Cost Reduction
• Cost reduction use relative costs as a parameter
• Some products require complex and expensive
production steps to process
• Design phase has the largest influence on the
quality and success of a product in the
marketplace
• Cost–benefit analysis requires reliable input data,
technical and human factors
50. Manufacturing Costs & Global
Competitiveness
• Cost of a product is taking into consideration
the product’s marketability and customer
satisfaction.
• Major impact on manufacturing includes:
1. Global competition
2. Market conditions fluctuated widely
3. Customers demand
4. Product complexity
