datum sequence planner

3-2-1 Datum Sequence Planner for Machined Parts | Zhenling

3-2-1 Datum Sequence Planner

Draft the datum discussion before sending a drawing for review. The planner follows the 3-2-1 contact concept, but the product designer remains responsible for functional datum selection and the released drawing.

Datum features

A · 3 points

B · 2 points

C · 1 point

Datums reflect assembly function Contact features are stable and repeatable Features are accessible for inspection

Generated drawing-review brief

Before release

Define basic dimensions and feature control frames from the same datum reference frame.
State which file controls if the 3D model and 2D drawing disagree.
Agree how each critical feature will be measured and reported.

Reference: GD&T technical guide for the datum reference frame and 3-2-1 contact sequence.

Send Drawing for Review

3-2-1 Datum Sequence Planner

Datum features

Generated drawing-review brief

Before release

Trending now