A review of the existing performance verification infrastructure for micro-CMMs

• Existing verification techniques available for micro-CMMs are reviewed.
• Three specification standards used in the testing of CMMs are considered for their relevance to micro-CMMs.
• A wide range of useful calibrated test lengths are reported.
• Conclusions are drawn on the current state of the verification landscape for micro-CMMs.
• Suggestions are made for future standardisation work.

The performance verification of micro-CMMs is now of intense interest because of their capability to perform length measurements in three dimensions to high accuracy with low uncertainties. Currently, verification of micro-CMMs is completed in the spirit of existing specification standards, because strict adherence to these standards is often difficult. This review aims to present and discuss verification techniques available for micro-CMMs: specification standards, existing calibrated test lengths and traceability routes that can be associated with micro-CMMs. Three specification standards used in the testing of CMMs will be considered. In addition, a wide range of calibrated test lengths are reported, and any advantages and disadvantages associated with their use are discussed. It is concluded that micro-CMMs cannot yet be verified in accordance with existing specification standards. Suggestions are made for future standardisation work required to rectify these issues.