Lecture 2

Question 1

What is Design for Manufacturing (DFM) focused on in material and process selection?

Answer 1

Design for Manufacturing (DFM) focuses on selecting materials and processes that optimize the production cost, quality, and efficiency while meeting design specifications.

Question 2

What is the primary concern in Design for Manufacturing and Assembly (DFMA) regarding material familiarity?

Answer 2

In DFMA, the primary concern is that designers often limit their designs to materials and processes they are familiar with, potentially overlooking more cost-effective alternatives.

Question 3

What are the main categories of manufacturing processes?

Answer 3

1. Primary shaping processes (e.g., casting, forging)
2. Secondary shaping processes (e.g., machining, grinding)
3. Joining processes (e.g., welding, fastening)
4. Surface treating processes (e.g., painting, coating)

Question 4

What are the four main classes of engineering materials?

Answer 4

1. Metals
2. Ceramics and Glasses
3. Polymers and Elastomers
4. Composites

Question 5

What is a characteristic of metals in engineering?

Answer 5

Metals have high moduli, can be strengthened through alloying and treatments, are ductile, and are least resistant to corrosion.

Question 6

What are the main attributes of ceramics and glasses?

Answer 6

Ceramics and glasses are high in modulus, brittle, abrasion-resistant, maintain strength at high temperatures, and are corrosion-resistant.

Question 7

What are the advantages of polymers and elastomers?

Answer 7

Polymers and elastomers have low moduli, are easily shaped, exhibit large elastic deflections, and are corrosion-resistant with a low coefficient of friction.

Question 8

What is unique about composite materials?

Answer 8

Composites combine properties from different material classes, are light, strong, and often include polymer matrices with fiber reinforcement, but cannot withstand high temperatures.

Question 9

List the steps involved in the DFMA process.

Answer 9

1. Create Design Concept with materials and processes.
2. Perform DFA analysis and make necessary changes.
3. Review and select materials.
4. Conduct DFM analysis; make changes if needed.
5. Build a prototype for the best design concept.

Question 10

What factors are considered in selecting materials and processes?

Answer 10

1. Quantity of parts required
2. Complexity (shape, size, features)
3. Quality of part
4. Manufacturing cost
5. Availability, lead time, and delivery schedule

Question 11

What is the systematic approach in material selection known as?

Answer 11

The systematic approach is known as Ashby Charts, developed by Professor Mike Ashby, for comparing materials during the conceptual design stage.

Question 12

What is the primary objective of a minimum weight design for structural components?

Answer 12

The primary objective is to minimize weight by selecting materials with the highest stiffness-to-weight or strength-to-weight ratio.