Introduction / Context:
Numeric precision on a drawing carries meaning. The number of decimal places often implies tolerance per a general note or standard block. Careless use drives unnecessary cost or creates ambiguity, resulting in nonconforming parts.
Given Data / Assumptions:
- A general tolerance note ties decimal precision to allowable variation (e.g., X.X ±0.1, X.XX ±0.01).
- Manufacturing methods have inherent capabilities (machining vs. sheet metal).
- Inspection plans rely on the tolerances communicated.
Concept / Approach:
Choose decimal places to match functional needs and realistic process capability. Overly tight precision inflates cost and scrap; overly loose precision risks poor fit or function. Apply geometric tolerances for form, orientation, and location where necessary.
Step-by-Step Solution:
Determine functional requirements and fit with mating parts.Select decimal places and associated tolerances per drawing standards or notes.Use GD&T where needed to control features critical to performance.Verify process capability aligns with specified tolerances before release.
Verification / Alternative check:
Discuss with suppliers or manufacturing engineers; confirm that tolerances are achievable and economical.
Why Other Options Are Wrong:
Correct: Suggests ignoring precision, which undermines quality.Only critical dimensions need decimals / CAD defaults choose decimals: All dimensions must intentionally reflect needed precision; defaults are starting points, not rules.
Common Pitfalls:
Using excessive precision everywhere, driving cost.Failing to define datums and positional tolerances for assemblies.
Final Answer:
Incorrect
Discussion & Comments