IELM215 Manufacturing Processes

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IELM215Manufacturing Processes

• II. Manufacture Design/Material/Process
  Selection

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Lecture Organization

• Examples or questions of how design/material/proce
  ss selection may affect the outcome of product.
• Selection Criteria from Material points of view
• Discussion of Mechanical Properties

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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 Material

Reading Assignment Material overview p.
43-45 Mechanical properties p. 64-70 (up to
sect. 2.2.3) Plastics Material p. 191-207
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Examples

• 1. 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?

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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

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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

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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

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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.

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Suggestion of How to Select the Best
Design/Material/ Process

• A good starting point--what is the best material
  and process to use?
• What is the lowest cost material?
• What is the lowest cost manufacturing process?
• Does the lowest cost manufacturing process
  compatible with the lowest cost material?

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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 ?L before Y (yield) elastic ductile
• Short ?L before Y (yield) brittle

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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?

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Examples to Utilize the Mechanical Parameters for
Product Design
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Examples to Utilize the Mechanical Parameters for
Product Design
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Ways to Improve Physical Properties

• Through Structures
• Rib structure or U shape or hollow structure can
  improve mechanical stiffness tremendously.
• Through composite
• Can provide light/ductile/strong/high damp
• 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

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Basic Knowledge of Plastics

• Please read Chapter 7

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Different Types Of Polymer Structures
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