CPT Manufacturing Processes & Assembly 3 — Questions and Answers
Question 1: What is 'tolerance stack-up' in assembly?
- Storing excess toleranced parts in a stack for later use
- The accumulation of individual part tolerances that can cause an assembly to exceed its overall tolerance (Correct answer)
- A method of sorting parts by tolerance class before assembly
- The process of tightening tolerances after initial assembly
Correct answer: The accumulation of individual part tolerances that can cause an assembly to exceed its overall tolerance
Tolerance stack-up occurs when individual part tolerances accumulate in an assembly, potentially causing the final assembly dimension to fall outside the acceptable range.
Question 2: In CNC machining, G-code G00 commands the machine to:
- Feed at a programmed rate while cutting
- Perform a canned drilling cycle
- Rapid traverse to a position without cutting (Correct answer)
- Return to the machine home position
Correct answer: Rapid traverse to a position without cutting
G00 is the rapid positioning command that moves the tool to the specified coordinates at the machine's maximum traverse speed, not at a programmed feed rate.
Question 3: Which surface finishing process uses abrasive particles suspended in a fluid to remove material from a workpiece interior?
- Shot peening
- Abrasive flow machining (Correct answer)
- Electropolishing
- Barrel tumbling
Correct answer: Abrasive flow machining
Abrasive flow machining (AFM) forces a semisolid abrasive media through or across a workpiece surface to deburr, polish, and radius edges in complex internal passages.
Question 4: When assembling a bolted joint, the correct sequence is typically:
- Torque to full spec immediately, then recheck
- Hand tighten all fasteners, then torque in a star pattern to full specification (Correct answer)
- Torque one fastener at a time to full spec before moving to the next
- Apply thread adhesive after torquing to final spec
Correct answer: Hand tighten all fasteners, then torque in a star pattern to full specification
Hand tightening all fasteners and then torquing in a cross (star) pattern evenly distributes clamping load and prevents gasket distortion or fastener binding.
Question 5: Which manufacturing process creates parts by compacting powdered metal in a die and then sintering the compact in a furnace?
- Extrusion
- Powder metallurgy (PM) (Correct answer)
- Forging
- Injection molding
Correct answer: Powder metallurgy (PM)
Powder metallurgy compacts metal powder into a desired shape and then sinters it below the melting point to bond the particles, producing near-net-shape parts with controlled porosity.
Question 6: What is the primary function of a hydraulic press in a manufacturing environment?
- To generate electrical power for CNC machines
- To apply large controlled forces for forming, stamping, or assembly operations (Correct answer)
- To measure pressure in pneumatic lines
- To filter hydraulic fluid in machine tool systems
Correct answer: To apply large controlled forces for forming, stamping, or assembly operations
A hydraulic press converts hydraulic pressure into mechanical force, enabling high-force operations such as forming, blanking, deep drawing, and press-fit assembly.
Question 7: In lean manufacturing, which type of waste refers to overproducing more than what is immediately needed?
- Waiting
- Overproduction (Correct answer)
- Transportation
- Defects
Correct answer: Overproduction
Overproduction — making more than is currently needed — is considered the worst of the seven wastes because it generates and hides all other types of waste.
CPT Manufacturing Processes & Assembly 3
What is 'tolerance stack-up' in assembly?