CPT Manufacturing Processes & Production 2 — Questions and Answers
Question 1: Which machining operation removes material by rotating a cutting tool against a stationary workpiece to create flat or contoured surfaces?
- Turning
- Milling (Correct answer)
- Drilling
- Broaching
Correct answer: Milling
Milling uses a rotating multi-point cutting tool to remove material from a stationary or fed workpiece, producing flat, slotted, or contoured surfaces.
Question 2: In injection molding, what is the purpose of the 'holding pressure' phase?
- To cool the mold rapidly
- To compensate for material shrinkage as the part solidifies (Correct answer)
- To eject the part from the mold
- To purge residual material from the barrel
Correct answer: To compensate for material shrinkage as the part solidifies
Holding pressure is applied after the mold cavity is filled to compensate for shrinkage as the molten plastic cools and solidifies, ensuring dimensional accuracy.
Question 3: What does 'takt time' represent in a lean manufacturing environment?
- The time required to set up a machine
- The average time between customer demand units (Correct answer)
- The total cycle time of the slowest operation
- The time a product spends waiting in a queue
Correct answer: The average time between customer demand units
Takt time is calculated as available production time divided by customer demand, representing the rate at which products must be completed to meet demand.
Question 4: Which welding process uses a non-consumable tungsten electrode and is commonly used for welding thin aluminum or stainless steel?
- MIG (GMAW)
- Stick (SMAW)
- TIG (GTAW) (Correct answer)
- Flux-Core (FCAW)
Correct answer: TIG (GTAW)
TIG (Gas Tungsten Arc Welding) uses a non-consumable tungsten electrode and an inert shielding gas, producing high-quality welds on thin or precision materials.
Question 5: A production run yields 480 good parts out of 500 attempted. What is the first-pass yield (FPY)?
- 92%
- 94%
- 96% (Correct answer)
- 98%
Correct answer: 96%
First-pass yield = (good parts / total attempted) × 100 = (480 / 500) × 100 = 96%.
Question 6: In CNC machining, what does G-code command G00 instruct the machine to do?
- Feed at a programmed rate
- Rapid traverse (non-cutting move) (Correct answer)
- Dwell at current position
- Tool change sequence
Correct answer: Rapid traverse (non-cutting move)
G00 commands a rapid positioning move at the machine's maximum traverse speed, used to quickly reposition the tool without cutting.
Question 7: Which heat treatment process involves heating steel above its critical temperature, then cooling it slowly in the furnace to improve machinability and relieve stress?
- Quenching
- Tempering
- Annealing (Correct answer)
- Case hardening
Correct answer: Annealing
Annealing heats metal above its recrystallization temperature and cools it slowly, softening the material, relieving internal stresses, and improving ductility and machinability.
CPT Manufacturing Processes & Production 2
Which machining operation removes material by rotating a cutting tool against a stationary workpiece to create flat or contoured surfaces?