How It Works

This skill audits a drawing for datum scheme correctness, GD&T completeness, and

inspectability. It focuses on translating function → datum reference frame → tolerance

zones → measurement plan.

The usual culprits: datum features chosen for convenience instead of functional assembly

constraints, missing or inconsistent datum reference frames, misuse of modifiers

(MMC/LMC), and incomplete feature control frames. The result is different inspectors

producing different results for the same part, shop feedback like "we don't know what

you meant," and parts that pass the print but fail functional gaging.

Datum scheme audit: identifies mismatches between your datum references and how the part is actually located in assembly
Feature control frame review: flags ambiguous, incomplete, or incorrect GD&T callouts
Corrected callout suggestions with proper datum references and modifiers
Inspection strategy outline: functional gauge vs CMM approach consistent with the corrected callouts
Single unambiguous interpretation across design, manufacturing, and inspection
Higher measurement repeatability and less CMM programming churn

The most common mistake is choosing datums for manufacturing convenience rather than functional assembly constraints — the skill checks this first
Watch for hidden dependencies like measuring what is covered by a datum simulator
Replace vague notes with explicit GD&T requirements whenever possible
Always run a cross-functional review (design + manufacturing + quality/metrology) after applying corrections
Example: two bores intended to define a datum axis, but inspection "picks circles at each end" — correct approach is to define the datum axis using the full datum feature simulator intent, then apply runout/position
For Y14.5-2018 updates, the skill flags where older conventions may cause ambiguity with current standard interpretations

GD&T Datum Scheme and Drawing Auditor