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1. Manufacturing Technology 1
Manufacturing TechnologyManufacturing Technology
LO #1 Design factors in Manufacturing Processes.
(Reference pages in the e-text : 1038 ~ 1040)

2. Design for Manufacturing and Assembly (DFMA)Design for Manufacturing and Assembly (DFMA)
2Manufacturing Technology
Soldering
Welding

3. Design for Manufacturing and Assembly (DFMA)Design for Manufacturing and Assembly (DFMA)
3Manufacturing Technology
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Definition
Consideration of all the relevant factors at the product design
stage itself to achieve ease of both manufacture and assembly.
Simple Example:
Design for manufacture (DFM) at a single part level, involves
details such as ensuring that where a pin is to be assembled into a
hole that is only slightly larger in diameter, then it is much easier if
the end of the pin or the entry to the hole (or both) are chamfered
or finished with a radius.

4. DFM/A requires the collaboration of designDFM/A requires the collaboration of design
engineers and manufacturing engineersengineers and manufacturing engineers
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 By forming project teams consisting of product designers,
manufacturing engineers, and other specialists (e.g. quality
engineers, material scientist) to design the product.
 Design engineers are required to spend some career time in
manufacturing to learn about the problem encountered in making
things.
 Manufacturing engineers assign to the product design
department as full-time consultant.

5. General Principles and guideline in DFM/AGeneral Principles and guideline in DFM/A
5Manufacturing Technology
1. Minimize number of components.
2. Use standard commercially available components.
3. Use common parts across product lines.
4. Design for ease part fabrication.
5. Design parts with tolerances that are within process capability.
6. Design the product to be foolproof(=very simple) during
assembly.
7. Minimize use flexible components.
8. Design for ease of assembly.
9. Use modular design.
10. Shape parts and products for ease packaging.
11. Eliminate or reduce adjustment required.

6. General Principles and guideline in DFM/AGeneral Principles and guideline in DFM/A
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 Assembly cost are reduced.
 The final product is more reliable because there are fewer
connection.
 Disassembly for maintenance and field service is easier.
 Reduced part count usually means automation is easier to
implement.
 Work-in-process is reduced, and there are fewer inventory
control problems.
 Fewer parts to be purchased, which reduces ordering costs.
1.Minimize number of components.

7. General Principles and guideline in DFM/AGeneral Principles and guideline in DFM/A
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1.Minimize number of components : An Example

8. General Principles and guideline in DFM/AGeneral Principles and guideline in DFM/A
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 Design time and effort are reduced.
 Design of custom-engineered components is avoided.
 There are fewer part numbers.
 Inventory control is facilitated.
 Quantity discounts may be possible.
2. Use standard commercially available components.

9. General Principles and guideline in DFM/AGeneral Principles and guideline in DFM/A
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2. Use standard commercially available components
– Examples : STD batteries, tires, bearings, screws, bolts,…

10. General Principles and guideline in DFM/AGeneral Principles and guideline in DFM/A
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 There is an opportunity to apply Group Technology (GT).
 Implementation of manufacturing cells may possible.
 Quantity discounts may be possible.
3. Use common parts across product lines.
GT (Group Technology) ;
- Similar parts are
grouped together to
improve
manufacturing
effectiveness.
- Ex) machines, tools,
and fixture.

11. General Principles and guideline in DFM/AGeneral Principles and guideline in DFM/A
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 Manufacturing cells
3. Use common parts across product lines.
- A group of equipment/resources.
- Usually arranged in the shape of “U”, which is dedicated to
produce similar products or a family of parts.

12. General Principles and guideline in DFM/AGeneral Principles and guideline in DFM/A
12Manufacturing Technology
 Net shape or near net shape processes may be feasible.
 Part geometry is simplified, and unnecessary features are
avoided.
 Unnecessary surface finish requirements should be avoided;
otherwise, additional processing may be needed.
4. Design for ease part fabrication.

13. General Principles and guideline in DFM/AGeneral Principles and guideline in DFM/A
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4. Design for ease part fabrication.

14. General Principles and guideline in DFM/AGeneral Principles and guideline in DFM/A
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 Tolerances tighter than the process capability should be
avoided; otherwise, additional processing or sortation will be
required.
 Bilateral tolerances should be specified.
5. Design parts with tolerances that are within process capability

15. General Principles and guideline in DFM/AGeneral Principles and guideline in DFM/A
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 Design should be unambiguous.
 Components should be designed so they can be assembled only one
way.
 Special geometric features must be added to components to achieve
foolproof assembly.
 Orientation problems are generally reduced designing a part to be
symmetrical and minimizing the number of asymmetric features.
6. Design the product to be foolproof during assembly.

16. General Principles and guideline in DFM/AGeneral Principles and guideline in DFM/A
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 Flexible components include parts made of rubber, belts,
gaskets, cables, etc.
 Flexible components are generally more difficult to handle and
assemble.
7. Minimize use flexible components

17. General Principles and guideline in DFM/AGeneral Principles and guideline in DFM/A
17Manufacturing Technology
 Part features such as chamfers and tapers should be designed
on mating parts.
 The assembly should be designed so that components are
added from one direction, usually vertically.
 Threaded fasteners (screw, bolts, nuts) should be avoided
where possible, especially when automated assembly used;
instead, fast assembly techniques such as snap fits and
adhesive bonding should be employed.
 The number of distinct fasteners should be minimized.
8. Design for ease of assembly.
Snap Fit Buckle

18. General Principles and guideline in DFM/AGeneral Principles and guideline in DFM/A
18Manufacturing Technology
 Modular design, or "modularity in design", is an approach that
subdivides a system into smaller parts (modules or skids) that can
be independently created and then used in different systems
to drive multiple functionalities.
(Ex.: Car parts, furniture, fridge…..)
 Maintenance and repair are facilitated.
 Inventory requirements are reduced.
 Final assembly time is minimized.
9. Use Modular Design

19. General Principles and guideline in DFM/AGeneral Principles and guideline in DFM/A
19Manufacturing Technology
 The product should be designed so that standard packaging
cartons can be used, which are compatible with automated
packaging equipment.
 Shipment to customer is facilitated.
10. Shape parts and products for ease packaging.

20. General Principles and guideline in DFM/AGeneral Principles and guideline in DFM/A
20Manufacturing Technology
 Adjustments are time consuming in assembly.
 Designing adjustments into the product means more
opportunities for out-of-adjustment conditions to arise.
11. Eliminate or reduce adjustment required

21. DFM/A – Benefits and AdvantagesDFM/A – Benefits and Advantages
21Manufacturing Technology
1. Shorter time to bring the product to market.
2. Smoother transition into production.
3. Fewer components in the final product.
4. Easy assembly.
5. Lower costs of production.
6. Higher product quality.
7. Greater customer satisfaction.