With a higher specific heat than metals, plastics take more energy to reach the melting point than metals do.
Question 1 options:
TrueFalse
Question 2 (3 points)
With low thermal conductivity, which metal replacement application would a polymer be best suited for?
Question 2 options:
Grease-lubricated ejector pins in an injection mold
CPU heat sink
Incandescent light fixture
Vacuum thermos
Question 3 (3 points)
Polymers may be modified via adding ceramic, metallic, or carbon based fillers to increase thermal conductivity somewhat above unmodified polymers, but well below metals. This modification will make the polymer stiff and brittle. Which metal replacement application would this material be best suited for?
Question 3 options:
Shock absorber
CPU heat sink
Cooling manifold for folding solar arrays
Assembly robot hydraulic oil lines
Question 4 (2 points)
What is an efficient way to heat polymer to the melting point?
Question 4 options:
Heated oil bath
Shear heating
Resistive heating
An oven
Question 5 (1 point)
Increasing the screw speed in an extruder will increase the heat generated
Question 5 options:
TrueFalse
Question 6 (1 point)
Increasing the compression ratio in an extruder will decrease the heat generated
Question 6 options:
TrueFalse
Question 7 (1 point)
Increasing the mass flow rate in an extruder will increase the heat generated
Question 7 options:
TrueFalse
Question 8 (1 point)
Decreasing the orifice size in an extruder will increase the heat generated
Question 8 options:
TrueFalse
Question 9 (Mandatory) (3 points)
A 2 in long nylon engine support has a CTE 2.0x10^-4 in/in*F. When heated from room temperature at 65 degrees to operating temperature at 190 degrees, what is the strain in in/in?
Question 9 options:
0.05
0.5
0.0025
0.025
Question 10 (Mandatory) (3 points)
4 2 in long nylon engine support has a CTE 2.0x10^-4 in/in*F. When heated from room temperature at 65 degrees to operating temperature at 190 degrees, what is the change in length in inches?
Question 10 options:
0.05
0.025
0.5
0.2525
Question 11 (Mandatory) (3 points)
The nylon has a modulus of 1.2*10^6 psi. Based on the strain, what is the stress generated?
Question 11 options:
30000
3000
60000
600000
Question 12 (Mandatory) (2 points)
The nylon has a yield stress 25,000 psi. Does this part fail?
Question 12 options:
Yes
No