Application of CMMs in precision parts inspection

The CMM is the core equipment for precision parts inspection. Hanweite's inspection room is equipped with a ZEISS CMM with 0.001mm measurement accuracy, used in a constant 20±2℃ environment. This article sets out the key actions in the daily inspection process.

I. Pre-inspection preparation

Workpieces must match the temperature of the measurement environment, usually requiring more than 2 hours resting in the inspection room. Surface cleanliness directly affects probe triggering stability, so oil and chips must be removed. The probe is calibrated with a reference sphere before use, with calibration values recorded.

II. Coordinate system setup

The coordinate system setup must match the drawing datum, which is the premise for reliable inspection results. A face-line-point method is preferred, with well-machined datum features; if the datum itself is rough, setup errors are amplified across all dimensions.

III. Measurement strategy

Features such as circles and cylinders need enough points, usually no fewer than 8; multiple measurements with averages are recommended for key fit dimensions. Thin-wall parts require controlled probing force to avoid the probe deforming them and producing low readings.

IV. Result evaluation and reporting

Inspection reports are delivered with the goods, including measured values, tolerances and evaluation conclusions. When deviations are found, the coordinate setup and probe status are rechecked first, and production is only notified after confirming a part problem, avoiding unnecessary rework from misjudgment.