The document outlines design principles for manufacturing, emphasizing the importance of understanding fabrication techniques to enhance quality and reduce costs. Key principles include minimizing part count, using standard materials, applying liberal tolerances, and collaborating with manufacturing personnel. Utilizing these principles can lead to better designs that are more reliable and cost-effective.

1. Design For Manufacturing

2. Flow of Design Knowledge
Engineering
Designers
Design
Specifications
The
Customer
M
anufacturing
Guidelines
Manuf.
Drawing
Package
Prototype/Product

3. Why Design for Manufacturing?
• Mechanical engineering designs generally
include off-the-shelf components and
fabricated parts.
• Knowing the strengths and limitations of the
fabrication techniques makes for higher
quality and more cost competitive designs.

4. Ten General Design Principles
(Chapter 1.3)
Simplicity
Standard Materials and
Components
Standardized Design of the
Product
Liberal Tolerances
Use Materials that are Easy to
Process
Teamwork with
Manufacturing Personnel
Avoidance of Secondary
Operations
Design to Expected Level of
Production
Utilize Special Process
Characteristics
Avoid Process
Restrictiveness

5. Simplicity
• Description: minimize the number of parts,
intricate shapes, and manufacturing
operations
• Motivation: generally provides reduced cost,
improved reliability, easier servicing, and
improved robustness

6. Part Count Reduction

8. Standard Materials and Components
• Description: Use standard off-the-shelf parts
and widely available materials
• Motivation: eases purchasing, simplifies
inventory management, and avoids tooling
investments
• Example: Screws

9. Standardized Design of the Product
• Description: For similar products, specify the
same materials, parts, and subassemblies as
much as possible.
• Motivation: provides economies of scale,
simplifies operations, and simplifies inventory
management
• Example: automotive platforms, Black &
Decker

10. Liberal Tolerances
• Description: make tolerances as forgiving as
possible
• Motivation: tight tolerances are expensive (in
a non-linear fashion)
• Example: Figure 1.3.1

12. Use Easily Processed Materials
• Description: take advantage of materials that
have been developed for easy processibility
• Motivation: while material may cost more, it
will often provide lower overall cost
• Example: “Free-Machining” Grades, Many
polymer grades are tuned to a process

13. Avoidance of Secondary Operations
• Description: minimize the need for secondary
operations
• Motivation: secondary operations (e.g.
deburring, inspection, painting, and heat
treating) can be as expensive as the primary
manufacturing operation
• Example: Pre-painted steel, investment
casting

14. Design to Expected Level of
Production

17. Understand and Utilize Manufacturing
Process Characteristics
• Description: understand and take advantage
of the special capabilities of various
manufacturing processes
• Motivation: can often eliminate
manufacturing operations and reduce the
number of parts
• Example: injection molding snap fits and living
hinges

18. Avoid Process Restrictiveness
• Description: on part drawings, specify only the
final characteristics needed; do not specify the
process to be used
• Motivation: potential cost savings

19. Teamwork with Manufacturing Personnel
• Description: collaborate with the people who
will be producing your product (the earlier the
better)
• Motivation: they provide a unique body of
knowledge and useful insights