Starrett provides calibration and preventive maintenance services on a contract basis for all of its vision metrology and optical comparator systems.
Preventive maintenance includes cleaning, lubrication, and a complete functional test of all subsystems and critical components. These include the stage, optical video probe, touch probe, and laser probe if on the system. If any errors are found, they are noted and are corrected on-site if possible, for example by realigning lead screws. A formal report is generated listing any problems that were found and what was done to correct them. If realignment and calibration cannot be done in the field, for example because a more complex rail collimation process is required, Starrett will so state and recommend that the equipment be factory rebuilt.
Following preventive maintenance and any realignment, calibration is performed using NIST-traceable glass standards and gage blocks. A laser interferometer is used for larger systems. A formal Calibration Certificate is issued following calibration.
The industry-standard interval for calibration of a metrology system is 1 year. The actual need for calibration depends on machine usage. A calibration interval longer than 1 year may be possible if only lightweight parts are measured, machine utilization is during a single shift, and tolerances are not critical. A calibration interval shorter than 1 year may be required if the parts are heavy, the machine is used during more than one shift, and tight tolerances have to be met. Starrett will recommend an appropriate calibration interval if an interval has not already been specified by the user’s policy.