BME Advanced Manufacturing 4 — Questions and Answers
Question 1: In statistical process control (SPC), a process is considered 'out of control' when:
- All points fall within the 3-sigma control limits
- A data point falls outside the control limits or a non-random pattern is detected (Correct answer)
- The process Cpk exceeds 1.33
- The sample size exceeds 30 measurements
Correct answer: A data point falls outside the control limits or a non-random pattern is detected
An out-of-control signal occurs when points exceed 3-sigma limits or when non-random patterns (runs, trends) indicate special cause variation.
Question 2: Which turning operation produces an internal cylindrical surface?
- Facing
- Boring (Correct answer)
- Threading
- Knurling
Correct answer: Boring
Boring uses a single-point tool to enlarge or finish an existing hole, producing an accurate internal cylindrical surface.
Question 3: What is the primary function of a fixture in a manufacturing setup?
- Cutting the workpiece to shape
- Locating and clamping the workpiece accurately and repeatably during machining (Correct answer)
- Measuring dimensional accuracy after machining
- Supplying cutting fluid to the tool
Correct answer: Locating and clamping the workpiece accurately and repeatably during machining
A fixture holds the workpiece in a precise, repeatable position and orientation relative to the cutting tool, ensuring dimensional consistency across multiple parts.
Question 4: In powder metallurgy, the green compact's density is primarily controlled by:
- Sintering temperature
- Compaction pressure applied during pressing (Correct answer)
- Particle chemical composition
- Cooling rate after sintering
Correct answer: Compaction pressure applied during pressing
Higher compaction pressure reduces porosity and increases green density by mechanically deforming and interlocking powder particles before sintering.
Question 5: Which of the following best describes the function of a transfer line in mass production?
- A conveyor that moves parts between separate factories
- A series of dedicated stations performing sequential operations automatically on moving workpieces (Correct answer)
- A software system for tracking part genealogy
- A quality control line for final inspection only
Correct answer: A series of dedicated stations performing sequential operations automatically on moving workpieces
A transfer line automatically moves workpieces through a fixed sequence of machining stations, enabling high-volume production of identical parts with minimal manual intervention.
Question 6: In abrasive waterjet (AWJ) machining, the role of the abrasive particles is to:
- Cool the workpiece surface
- Erode material through high-velocity impact and micro-cutting (Correct answer)
- Lubricate the jet nozzle
- Chemically react with the workpiece material
Correct answer: Erode material through high-velocity impact and micro-cutting
Abrasive particles entrained in the high-velocity water jet impact and micro-cut the workpiece surface, enabling machining of hard materials like titanium and ceramics.
Question 7: What is the main purpose of normalizing a steel component after forging?
- Increasing carbon content to maximum solubility
- Relieving residual stresses and refining grain structure for uniform properties (Correct answer)
- Hardening the surface to resist wear
- Reducing the melting point for subsequent casting
Correct answer: Relieving residual stresses and refining grain structure for uniform properties
Normalizing involves heating above the upper critical temperature and air cooling, which refines the coarse forged grain structure and homogenizes mechanical properties.
BME Advanced Manufacturing 4
In statistical process control (SPC), a process is considered 'out of control' when: