Coordinate Measuring Machine (CMM) Checking Gage

March 08, 2023
CMM Checking Gage Confirms Accuracy of Measuring Machines After Calibration

A new range of UKAS-certified length and form gages, complete with holding fixture, has been introduced by coordinate measuring machine (CMM) manufacturer LK Metrology, allowing the inspection accuracy of any 3D measuring platform to be verified. The user can have greater confidence in the results of an inspection, whether for metrology or reverse engineering, long after the typical annual calibration of the measuring machine has been carried out.

Each CMM Checking Gage (CCG) enables independent monitoring and verification of accuracy through regular intermediate checks on a CMM or portable measuring arm. An OEM can be certain that prototypes and production parts are within tolerance, while subcontractors are able to assure their customers that machining and inspection carried out on their behalf are accurate. It demonstrates a commitment to a consistently high standard of dimensional quality control. Gage measurement tolerance is ± 0.01 μm.

CCG provides an efficient go/no-go check with measurement results for ongoing CMM monitoring. Three combinations of length bars, ring gage, test sphere and fixture of different sizes are available to suit various measuring machine models. Regular use provides an early warning of changes in the inspection system and an opportunity to take pre-emptive action. Once identified, accuracy issues due perhaps to environmental changes or an unnoticed probe crash can be addressed by scheduling an interim machine service or calibration before downstream manufacturing processes are impacted.

The gage is supplied in a carrying case with a program on a USB drive that runs in LK's CAMIO measuring and reporting software. The program includes DMIS measurement and alignment routines for bridge and horizontal arm CMMs, allowing the CCG cycle to run seamlessly on LK machines. However, it is easy for operators of other 3D measuring platforms using different software to program a probing cycle around the gage to check for machine accuracy.

Related Glossary Terms

  • calibration


    Checking measuring instruments and devices against a master set to ensure that, over time, they have remained dimensionally stable and nominally accurate.

  • fixture


    Device, often made in-house, that holds a specific workpiece. See jig; modular fixturing.

  • metrology


    Science of measurement; the principles on which precision machining, quality control and inspection are based. See precision machining, measurement.

  • quality assurance ( quality control)

    quality assurance ( quality control)

    Terms denoting a formal program for monitoring product quality. The denotations are the same, but QC typically connotes a more traditional postmachining inspection system, while QA implies a more comprehensive approach, with emphasis on “total quality,” broad quality principles, statistical process control and other statistical methods.

  • tolerance


    Minimum and maximum amount a workpiece dimension is allowed to vary from a set standard and still be acceptable.