Michigan Plastic Fabricator Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
1. Which of the following polymers is most commonly used in blow
molding for large hollow products such as tanks?
A. PVC
B. HDPE
C. PS
D. ABS
HDPE is widely used in blow molding due to its excellent chemical
resistance, low cost, and ability to form large hollow shapes.
2. What process is best suited for producing high-volume, complex,
precision parts with excellent surface finish?
A. Compression molding
B. Injection molding
C. Rotational molding
D. Thermoforming
Injection molding enables fast production of intricate designs with
tight tolerances and high surface quality.
3. Which of the following is a key advantage of annealing plastic parts?
A. Increased shrink rate
B. Decreased toughness
C. Reduced internal stresses
D. Higher molding temperatures
Annealing relieves internal stresses induced during processing,
improving dimensional stability.
,4. What does the melt flow index (MFI) of a thermoplastic indicate?
A. Density variation
B. Molecular isotacticity
C. Flowability under specified conditions
D. Glass transition temperature
MFI measures how easily a polymer flows when melted, which helps
predict processing behavior.
5. In extrusion, what is the purpose of the breaker plate?
A. Increase melt temperature
B. Provide uniform flow and support screen pack
C. Cool the melt
D. Remove volatiles
The breaker plate creates a pressure drop and supports the screen
pack, ensuring consistent melt distribution.
6. Which defect in injection molded parts is characterized by internal
voids or bubbles?
A. Flash
B. Sink marks
C. Voiding
D. Weld lines
Voiding occurs when trapped gas or shrinkage causes internal
cavities in the molded part.
7. What is the primary function of a hopper dryer in plastic processing?
A. Melt polymer
B. Cool molds
C. Remove moisture from resins
D. Calibrate extruded profiles
Drying resins prevents hydrolytic degradation and ensures quality
processing.
8. Which polymer has a glass transition temperature around 105°C and is
commonly used in automotive parts?
A. LDPE
B. Polypropylene (PP)
C. Polystyrene (PS)
D. Polycarbonate (PC)
, Polypropylene has a Tg near 105°C and is widely used in automotive
applications.
9. In thermoforming, what is the term for the vacuum application that
shapes the heated sheet?
A. Blow-up
B. Vacuum draw
C. Compression stamp
D. Melt pull
Vacuum draw pulls the heated sheet into the mold to conform to its
shape.
10. Which process is ideal for creating large, seamless hollow parts
with low tooling cost?
A. Injection molding
B. Rotational molding
C. Blow molding
D. Thermoforming
Rotational molding produces large hollow shapes with minimal
tooling expenses.
11. What property describes a material’s ability to return to its
original shape after deformation?
A. Brittleness
B. Creep
C. Elasticity
D. Thermal expansion
Elasticity is a measure of a material’s resilience after stress removal.
12. What type of plastic shrinkage occurs as molten polymer cools
and solidifies?
A. Secondary shrinkage
B. Primary shrinkage
C. Crystalline expansion
D. Thermal stress inversion
Primary shrinkage is the reduction in part size due to cooling from
melt to solid state.
13. Which safety hazard is directly associated with overheating
plastics during processing?
Practice Questions And Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
1. Which of the following polymers is most commonly used in blow
molding for large hollow products such as tanks?
A. PVC
B. HDPE
C. PS
D. ABS
HDPE is widely used in blow molding due to its excellent chemical
resistance, low cost, and ability to form large hollow shapes.
2. What process is best suited for producing high-volume, complex,
precision parts with excellent surface finish?
A. Compression molding
B. Injection molding
C. Rotational molding
D. Thermoforming
Injection molding enables fast production of intricate designs with
tight tolerances and high surface quality.
3. Which of the following is a key advantage of annealing plastic parts?
A. Increased shrink rate
B. Decreased toughness
C. Reduced internal stresses
D. Higher molding temperatures
Annealing relieves internal stresses induced during processing,
improving dimensional stability.
,4. What does the melt flow index (MFI) of a thermoplastic indicate?
A. Density variation
B. Molecular isotacticity
C. Flowability under specified conditions
D. Glass transition temperature
MFI measures how easily a polymer flows when melted, which helps
predict processing behavior.
5. In extrusion, what is the purpose of the breaker plate?
A. Increase melt temperature
B. Provide uniform flow and support screen pack
C. Cool the melt
D. Remove volatiles
The breaker plate creates a pressure drop and supports the screen
pack, ensuring consistent melt distribution.
6. Which defect in injection molded parts is characterized by internal
voids or bubbles?
A. Flash
B. Sink marks
C. Voiding
D. Weld lines
Voiding occurs when trapped gas or shrinkage causes internal
cavities in the molded part.
7. What is the primary function of a hopper dryer in plastic processing?
A. Melt polymer
B. Cool molds
C. Remove moisture from resins
D. Calibrate extruded profiles
Drying resins prevents hydrolytic degradation and ensures quality
processing.
8. Which polymer has a glass transition temperature around 105°C and is
commonly used in automotive parts?
A. LDPE
B. Polypropylene (PP)
C. Polystyrene (PS)
D. Polycarbonate (PC)
, Polypropylene has a Tg near 105°C and is widely used in automotive
applications.
9. In thermoforming, what is the term for the vacuum application that
shapes the heated sheet?
A. Blow-up
B. Vacuum draw
C. Compression stamp
D. Melt pull
Vacuum draw pulls the heated sheet into the mold to conform to its
shape.
10. Which process is ideal for creating large, seamless hollow parts
with low tooling cost?
A. Injection molding
B. Rotational molding
C. Blow molding
D. Thermoforming
Rotational molding produces large hollow shapes with minimal
tooling expenses.
11. What property describes a material’s ability to return to its
original shape after deformation?
A. Brittleness
B. Creep
C. Elasticity
D. Thermal expansion
Elasticity is a measure of a material’s resilience after stress removal.
12. What type of plastic shrinkage occurs as molten polymer cools
and solidifies?
A. Secondary shrinkage
B. Primary shrinkage
C. Crystalline expansion
D. Thermal stress inversion
Primary shrinkage is the reduction in part size due to cooling from
melt to solid state.
13. Which safety hazard is directly associated with overheating
plastics during processing?
