Some small geometries of microparts (such as vertical flanks of e.g. micro gears) are hard to access for optical sensors. Therefore, Werth Messtechnik GmbH in Giessen, Germany, has developed a tactile-optical sensor. The company’s Werth Fiber Probe was designed for microparts. It links tactile probing and extraordinarily precise measuring to image processing.

Micro gears are measured by a fiber probe (same supplier) in a scanning mode. This enables high density in measuring points, with accuracies below one micrometer. To measure a profile, several sections of the entire profile are scanned. On the basis of the CAD data set, the cuts can then be compared in a color-coded 3-D CAD presentation, to show deviations. Graphical evaluation of the cuts can also be conducted on a computer (using programs such as 2D-BestFit or 2D-ToleranceFit).

To further analyze all measured data, the gear measuring program Involute Pro is available. It detects gear parameters such as profile deviations of involutes and flanks, deviations in tooth thicknesses, surface topographies or concentricity.