基准

定义

用于检验或加工的参考要素。

以前置元数据中的定义作为统一语义，并在装夹、加工与检验环节保持一致。

公式/规则

• 在接受补偿或检验结果前，先锁定主、次、第三基准的建立顺序。
• 一旦基准发生变化，必须重新找正并复核所有依赖尺寸。

典型范围

• Use the same datum scheme from setup sheet to CMM report so result interpretation does not drift.
• If the drawing switches datums, treat it as a new verification condition.

现场场景

• Re-establish the datum after reclamping a part before trusting previous offset values.
• Use the datum hierarchy to decide whether an out-of-position feature comes from setup or toolpath.

常见错误/排障

• If measurement results conflict between operators, verify that the same datum feature and probing sequence were used.
• If offsets are repeatedly corrected in the wrong direction, confirm that the setup zero still matches the intended datum.

相关工具

• Gdt Reference
• True Position Calculator