ME or MEng Master of Engineering Master of Engineering Computer-Aided Manufacturing 3 — Questions and Answers
Question 1: What does the term 'process capability index Cpk' measure in statistical process control?
- The ratio of total process variation to specification width
- How well a centered process fits within specification limits
- The degree to which a process is both centered and within specification limits (Correct answer)
- The number of defects per million opportunities
Correct answer: The degree to which a process is both centered and within specification limits
Cpk accounts for both process spread and mean shift relative to specification limits, indicating actual process capability.
Question 2: In robotic manufacturing cells, which sensor type is most effective for detecting surface defects on shiny metallic parts?
- Ultrasonic sensors
- Structured light 3D scanners (Correct answer)
- Capacitive proximity sensors
- Thermocouple arrays
Correct answer: Structured light 3D scanners
Structured light scanning projects patterns onto surfaces and captures reflected geometry, enabling high-resolution defect detection even on reflective materials.
Question 3: Which STEP (Standard for the Exchange of Product model data) protocol is used to transfer CAD geometry between different software platforms?
- STEP AP203 (Correct answer)
- IGES v6.0
- DXF R14
- STL binary format
Correct answer: STEP AP203
STEP AP203 (Application Protocol 203) defines the exchange of configuration-controlled 3D design data between CAD systems.
Question 4: In finite element analysis (FEA) for manufacturing, what is the effect of using a finer mesh near stress concentrations?
- It reduces solution accuracy by introducing numerical noise
- It increases solution accuracy by better capturing high stress gradients (Correct answer)
- It has no effect on results if the global mesh is uniform
- It only affects thermal simulations, not structural ones
Correct answer: It increases solution accuracy by better capturing high stress gradients
Finer meshes near stress concentrations capture steep stress gradients more accurately, reducing discretization error.
Question 5: What manufacturing defect does the term 'chatter' refer to in milling operations?
- Tool breakage due to excessive feed rate
- Self-excited vibration causing poor surface finish and dimensional error (Correct answer)
- Chip jamming in the flute of an end mill
- Thermal expansion of the workpiece during cutting
Correct answer: Self-excited vibration causing poor surface finish and dimensional error
Chatter is regenerative self-excited vibration between tool and workpiece, producing wavy surfaces and accelerating tool wear.
Question 6: In the context of CAM for additive manufacturing, what is 'support structure optimization' primarily designed to minimize?
- Total build time regardless of material usage
- Material waste and post-processing labor while ensuring structural support (Correct answer)
- The number of layer raster passes
- Laser power consumption only
Correct answer: Material waste and post-processing labor while ensuring structural support
Optimized support structures reduce material use and difficult-to-remove supports while preventing part collapse during printing.
Question 7: Which simulation method is best suited for modeling metal flow during a closed-die forging process?
- Rigid body dynamics
- Computational Fluid Dynamics (CFD)
- Finite Element Method with remeshing (FEM) (Correct answer)
- Discrete Element Method (DEM)
Correct answer: Finite Element Method with remeshing (FEM)
FEM with adaptive remeshing handles the large plastic deformations and contact conditions characteristic of closed-die forging.
ME or MEng Master of Engineering Master of Engineering Computer-Aided Manufacturing 3
What does the term 'process capability index Cpk' measure in statistical process control?