CDT Quality Control & Inspection 3 — Questions and Answers
Question 1: On a drawing using third-angle projection, the right-side view is placed:
- To the left of the front view
- To the right of the front view (Correct answer)
- Below the front view
- Above the front view
Correct answer: To the right of the front view
In third-angle projection (standard in the US), the right-side view is projected to the right of the front view.
Question 2: A QC checklist item requires verifying that all surface finish symbols on a drawing are consistent with the specified manufacturing process. This is an example of:
- Geometric tolerance verification
- Process-drawing compatibility review (Correct answer)
- Revision level audit
- Datum hierarchy check
Correct answer: Process-drawing compatibility review
Checking that surface finish callouts are achievable and consistent with the specified process is a process-drawing compatibility review.
Question 3: When a drawing tolerance stack-up analysis reveals that worst-case assembly clearance is negative, the correct response is to:
- Accept the condition since statistical assembly will rarely produce interference
- Tighten individual part tolerances or redesign to achieve positive clearance (Correct answer)
- Increase the assembly clearance in the model only
- Issue a waiver for all affected assemblies
Correct answer: Tighten individual part tolerances or redesign to achieve positive clearance
A negative worst-case clearance means parts can physically interfere, requiring tighter tolerances or a design change before production.
Question 4: Which symbol on a GD&T drawing indicates that a cylindrical tolerance zone is to be applied?
- The square symbol □
- The diameter symbol ⌀ preceding the tolerance value (Correct answer)
- The S⌀ symbol
- The R symbol
Correct answer: The diameter symbol ⌀ preceding the tolerance value
Placing the diameter symbol ⌀ before a tolerance value in a feature control frame indicates a cylindrical (diametral) tolerance zone.
Question 5: During a CAD model QC review, a technician finds that the 3D model and the 2D drawing have conflicting hole depths. Which document is typically the governing authority under ASME Y14.41 model-based definition?
- The 2D drawing always governs
- The 3D annotated model governs if designated as the master (Correct answer)
- The BOM governs
- Whichever document was created first governs
Correct answer: The 3D annotated model governs if designated as the master
Under ASME Y14.41, when a 3D annotated model is designated as the master reference, the model dataset takes precedence over 2D derived drawings.
Question 6: A drawing calls out a positional tolerance of ⌀0.010 at maximum material condition (MMC) for a pin. If the pin is produced at its least material condition (LMC), the allowable positional tolerance:
- Remains ⌀0.010
- Decreases to below ⌀0.010
- Increases by the departure from MMC (Correct answer)
- Is converted to a bilateral tolerance
Correct answer: Increases by the departure from MMC
Under MMC modifier rules, as the feature departs from MMC toward LMC, the bonus tolerance equals the departure amount, increasing total allowable position.
Question 7: What is the purpose of a 'checker stamp' or 'checker approval' block on an engineering drawing?
- To indicate the part is approved for mass production
- To confirm that an independent reviewer has verified the drawing for accuracy and completeness (Correct answer)
- To show the drawing has been exported to PDF
- To certify that the material specification is correct
Correct answer: To confirm that an independent reviewer has verified the drawing for accuracy and completeness
A checker stamp confirms that a qualified person independent of the originator has reviewed the drawing for errors, omissions, and standard compliance.
CDT Quality Control & Inspection 3
On a drawing using third-angle projection, the right-side view is placed: