BME Advanced Manufacturing 2 — Questions and Answers
Question 1: In selective laser sintering (SLS), what material property is most critical for achieving dense, high-strength parts?
- Melting point
- Particle size distribution (Correct answer)
- Electrical conductivity
- Surface reflectivity
Correct answer: Particle size distribution
Particle size distribution directly affects packing density and energy absorption, determining final part density and strength in SLS.
Question 2: Which of the following best describes the role of cutting fluid in high-speed machining?
- Increasing tool hardness
- Reducing thermal damage and chip adhesion (Correct answer)
- Increasing workpiece hardness
- Improving surface oxidation
Correct answer: Reducing thermal damage and chip adhesion
Cutting fluids dissipate heat and lubricate the tool-chip interface, preventing built-up edge formation and thermal damage.
Question 3: What is the primary advantage of using a five-axis CNC machine over a three-axis machine?
- Higher spindle speed
- Ability to machine complex contoured surfaces in fewer setups (Correct answer)
- Lower tooling cost
- Faster rapid traverse rates
Correct answer: Ability to machine complex contoured surfaces in fewer setups
Five-axis machines tilt the tool relative to the workpiece, enabling complex curved surfaces to be machined with fewer repositioning setups.
Question 4: In electrical discharge machining (EDM), material removal is achieved by:
- Mechanical abrasion from a conductive wheel
- Controlled electrical sparks eroding the workpiece (Correct answer)
- Chemical dissolution in electrolyte
- Laser ablation through a conductive medium
Correct answer: Controlled electrical sparks eroding the workpiece
EDM removes material through rapid electrical discharges (sparks) between the electrode and workpiece, vaporizing small amounts of material.
Question 5: Which lean manufacturing waste category does excess inventory between production stages represent?
- Motion
- Overproduction (Correct answer)
- Waiting
- Transportation
Correct answer: Overproduction
Excess inventory between stages is classified as overproduction waste, tying up capital and hiding process problems.
Question 6: In metal injection molding (MIM), what is the purpose of the debinding stage?
- Compacting the metal powder
- Removing the polymer binder before sintering (Correct answer)
- Adding alloying elements
- Quenching the part to increase hardness
Correct answer: Removing the polymer binder before sintering
Debinding removes the polymer binder system from the green part, leaving a porous metal skeleton that is subsequently sintered to full density.
Question 7: What does the term 'tool life' typically refer to in machining operations?
- The total cost of the cutting tool
- The cutting time before a tool reaches a predefined wear criterion (Correct answer)
- The number of tools available in the magazine
- The depth of cut a tool can achieve
Correct answer: The cutting time before a tool reaches a predefined wear criterion
Tool life is the total cutting time a tool operates before it must be replaced or re-sharpened, defined by a specific flank wear or surface finish criterion.
BME Advanced Manufacturing 2
In selective laser sintering (SLS), what material property is most critical for achieving dense, high-strength parts?