Physikalisch-Technische Bundesanstalt

Miniaturization in technology leads to components with decreasing size such as e.g. micro-gears and micro-optical components with features smaller than 0.5 mm down to 1 μm. To measure microcomponents today, optical, tactile and x-ray-tomographic micro-sensors are used. Their verification should be carried out in accordance with accepted procedures of coordinate measuring technology (ISO 10360, VDI/VDE 2617). These procedures utilize artifacts.  Micro-artifacts with suitable dimensions have so far not been available.

PTB has therefore developed different micro-artifacts which have “cooperative” surfaces for tactile and optical probing or can be measured by x-ray computed tomography due to their volume properties (e.g. x-ray absorption). For the manufacture of these micro-artifacts, different manufacturing processes, such as wire-cut or die-sinking EDM or diamond turning were used. In some cases, the surfaces had to be subsequently structured, e.g. by laser processing, to achieve metrologically suitable surfaces.

Comparison measurements with different tactile and optical microsensors on a micro-contour standard showed agreements of sometimes more than 1 μm for distances and radii. With the development of the micro-artifacts and the corresponding calibration procedures, a decisive step towards the qualified comparison of different sensors and their traceability in the microrange has been made. In some cases, the artifacts could be transferred to industry within the scope of cooperative projects.

A future task will be a further miniaturization of the artifacts and structures, as well as the reduction of the calibration uncertainty in order to meet the ever growing demands on the verification of more and more accurate measuring devices for artifacts that are becoming smaller and smaller. alibration uncertainties of 0.1 μm and better are aimed at for tactile and optical measurements.