Dimensional Metrology · 4 min read
CMM Calibration vs. Verification
A coordinate measuring machine measures in three dimensions, so "is it accurate?" is a bigger question than for a caliper. That is why CMMs are handled through performance verification, not a single calibration point.
Part of our guide to Dimensional Metrology.
Performance verification
CMM performance is typically verified against standards such as the ISO 10360 series, using calibrated artifacts (ball bars, gauge blocks, step gauges) to check length-measuring error and probing error across the machine’s volume. The result characterizes how the machine performs throughout its working space, not just at one location.
Interim checks keep it honest between verifications
Because a full verification is involved, many shops run interim checks — a known artifact measured periodically — to catch problems between formal verifications. Combined with environmental control and good probing practice, this keeps confidence high without waiting a year to discover drift. The reference artifacts themselves must be calibrated and traceable, which is where an accredited lab supports your CMM program.
Common questions
Do you calibrate CMMs on-site?
CMM performance verification is often performed where the machine sits, using calibrated artifacts. The artifacts and reference instruments require traceable calibration — contact us to discuss your CMM support and artifact calibration needs.