Two Alignments, One Part: Which Result Do You Trust? | CMM Applied Skills

Описание: When two alignments give two verdicts on the same part, the drawing's datum scheme is the referee — how to compare frames, quantify their difference, and defend the right one.

In this applied lesson you will learn:

Why two alignments of the same part answer different questions — a datum alignment reproduces the functional frame the assembly sees, while a best-fit alignment minimises residuals and can pull the frame away from the datums.
Why the correct frame for a characteristic is the one its datum reference frame defines — the datum frame governs release, and a best-fit frame is an analysis tool, not a release frame.
The settling sequence — compare constructions before numbers, quantify the translation and rotation between frames, interrogate the alignment features themselves, and re-measure a stable check standard under both alignments.
The three ways to lose the truth — frame shopping for a pass, averaging two frames, and letting a convenience alignment become the release alignment.

Chapters

00:00 The part did not change
00:12 Frames answer questions
01:19 Settling the argument
02:15 Three ways to lose the truth
02:43 Recap checklist

Safety note: Illustrated training lesson. Schematics only — no live machine operation. Verify workflow against your site procedure.

Series: CMM Applied Skills — Tan Ho · CMM to AI