The form properties of products that are assembled and co-operate with each other are of utmost importance. Since the dimensional accuracy of high accuracy standards also depends on the form properties, form measurements are important. In short, form error is defined as the deviation of the shape of the product from the relevant ideal geometric shape (line, plane, circle, cylinder, etc.). Geometric form is expressed mathematically and there is no primary level standard. For this reason, measurement systems that can reproducibly generate geometric form without relying on a physical reference standard can be used for high-accuracy measurements of form parameters. With the help of error separation techniques, the form errors of the device can be detected and separated during the measurement and only the form errors of the measured surface can be detected at the primary level with high accuracy.

Linearity and steepness measurements are performed with the application of the error separation technique using a CMM device. The data taken with the CMM device is transferred to the software written by the laboratory, CMM errors are separated and the steepness and linearity errors of the standard are determined.

Planarity measurements of granite tables and slabs (plates), whose surfaces are used as reference, are carried out with electronic level meters and special software that evaluates the data received with these devices.

Measurements such as roundness, straightness, parallelism, cylindricity, etc. are performed using Mahr MFU800 and Mahr MMQ40 form measuring machines. Error separation methods are used for high accuracy measurements.

Diameter standards and other gauges are calibrated using a Mahr 828 CiM instrument modified by our laboratory. The instrument is equipped with a temperature control cabinet, temperature gauges and remotely controlled motor mechanisms that allow the measurement to be performed from outside the cabinet. Diameter standards up to 300 mm are calibrated using the gage substitution method.