IELM, HKUST Prof Neville Lee IELM215 Manufacturing Processes II.Manufacture Design/Material/Process...
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Transcript of IELM, HKUST Prof Neville Lee IELM215 Manufacturing Processes II.Manufacture Design/Material/Process...
IELM, HKUST Prof Neville Lee
IELM215Manufacturing Processes
II. Manufacture Design/Material/Process
Selection
IELM, HKUST Prof Neville Lee
Lecture Organization
1. Examples or questions of how design/material/process selection may affect the outcome of product.
2. Selection Criteria from Material points of view
3. Discussion of Mechanical Properties
IELM, HKUST Prof Neville Lee
Lecture Organization (cont.)
4. Examples of How to Utilize the Mechanical Parameters for Product Design
5. Ways to Improve Mechanical Properties
6. Discussion on Plastics MaterialReading Assignment:Material overview – p. 43-45Mechanical properties – p. 64-70 (up to sect. 2.2.3)Plastics Material – p. 191-207
IELM, HKUST Prof Neville Lee
Examples1. Which would you choose to make a
telescope (pen) barrel? Molding vs. Machining Plastics vs. Metal
(Hint: the answer depends on the volume).
2. Gold is pretty and would not oxidize, but expensive. Iron is strong and cheap, but not pretty and oxidizes. Which would you choose for the elevator door for an expensive hotel? Any other suggestions?
IELM, HKUST Prof Neville Lee
Examples (cont.)4. If you work for a car manufacturer, there is a lot
of pressure to lower the cost and to improve the fuel economy. Are there any suggestions that you can tell your boss?
5. Plastics bag is cheap and is easy to seal. However, it is permeable to air but cannot keep food for a long time. Aluminum foil is not permeable to air but cannot seal easily and is more expensive. Would you have a good solution for a peanut packaging company?
6. How do you design a table that is light and yet still very strong
IELM, HKUST Prof Neville Lee
Selection Criteria Meet the functional requirements Lowest overall cost
Material cost Equipment cost Operation cost such as facility and energy
cost Quality Speed to market
IELM, HKUST Prof Neville Lee
Factors to be considered Material selection
Types of Materials Properties Cost Process requirements
Process selection Tolerance requirement Equipment / Facility requirement Speed of production Labor & operating cost
Alternative structural design
IELM, HKUST Prof Neville Lee
IELM, HKUST Prof Neville Lee
IELM, HKUST Prof Neville Lee
Selection Criteria From Material Points Of View Please name the four major types of engineering
material commonly used for manufacturing
What are there major characteristics, or advantages and disadvantages?
What are the main physical parameters which one should consider in selection of the material?
Electrical – conductivity Magnetic – for motor etc. Optical properties Chemical – corrosion resistance Thermal – conductivity, melting point etc Mechanical – strength, hardness etc.
IELM, HKUST Prof Neville Lee
Suggestion of How to Select the Best Design/Material/ Process
A good starting point--what is the best material and process to use?
1. What is the lowest cost material?2. What is the lowest cost manufacturing
process?3. Does the lowest cost manufacturing
process compatible with the lowest cost material?
IELM, HKUST Prof Neville Lee
Quick Look At Mechanical Property
For a material, do you know the difference between strong, hard, ductile or brittle, elastics?
Roughly speaking: Large E (modulus) – stiff Large E and Y – hard Large Y (yield stress) and UTS (ultimate tensile
strength) – strong Long ΔL before Y (yield) – elastic ductile Short ΔL before Y (yield) – brittle
IELM, HKUST Prof Neville Lee
Quick Look At Mechanical Property (cont.) Let say you need to design
something, how do you determine if the design is strong enough? Or how would you select the material?
Please see the following two examples in II.4. There will also be exercise to ensure you know the material.
Do you know how to use the mechanical properties table?
IELM, HKUST Prof Neville Lee
IELM, HKUST Prof Neville Lee
IELM, HKUST Prof Neville Lee
IELM, HKUST Prof Neville Lee
IELM, HKUST Prof Neville Lee
Examples to Utilize the Mechanical Parameters for Product Design
IELM, HKUST Prof Neville Lee
Examples to Utilize the Mechanical Parameters for Product Design
IELM, HKUST Prof Neville Lee
Ways to Improve Physical Properties 1. Through Structures
Rib structure or U shape or hollow structure can improve mechanical stiffness tremendously.
2. Through compositeCan provide light/ductile/strong/high damp
3. Through coating process
There are many examples: Cosmetics – Lip sticks Reflective – CD Corrosion resistance – Paint Lubrication – Grease or oil Non sticking – Teflon Wear resistance – Diamond
IELM, HKUST Prof Neville Lee
IELM, HKUST Prof Neville Lee
Basic Knowledge of Plastics Please read Chapter 7
IELM, HKUST Prof Neville Lee
IELM, HKUST Prof Neville Lee
Different Types Of Polymer Structures
IELM, HKUST Prof Neville Lee
IELM, HKUST Prof Neville Lee