Indicate why design rules must be followed after a preliminary ...

[NClaborn]

Indicate why design rules must be followed after a preliminary choice is made of both process and material.
 
  What will be an ideal response?

Question 2

Performance tests of valve lifters in an automobile engine showed distortion when the material used was 20 glass-reinforced nylon (6/6). Explain why a shift to a higher crystalline polymer was suggested.
 
  What will be an ideal response?

[briseldagonzales]

Answer to Question 1

The design rules are both process and material specific. For instance, the shrinkage that is to be allowed would vary depending on the material and might be different if the process chosen does not melt the resin, say with rotomolding instead of a melting process such as injection molding.

Answer to Question 2

The higher crystalline polymer would have more hydrogen bonding sites per unit of polymer length and would, therefore, have more inter-molecular interactions and a higher performance temperature.

[NClaborn]

Excellent

[tanna.moeller]

Great answer, keep it coming