Roundness and straightness measurement

A new rotary axis solution in combination with the corresponding software now makes it possible to measure roundness and straightness on the coordinate measuring machine with previously unattained accuracy. In particular, the patented Rasterscanning HD operating mode and the new RotaryScan HD are used here. Thanks to a high-precision telecentric lens, a rotary axis with air bearings and a new correction method, minimal measurement errors in the range of 200 nm are achieved for the reliable detection of roundness tolerances down to 2 μm.

One application, for example, is the measurement of the straightness of the outer cylinder of control pistons for hydraulic applications. During the movement of the machine axes – but without movement of the rotary axis – the outer contour of the workpiece is captured with the maximum possible number of images. The overall image generated by superimposing the individual images enables fast “in the image” evaluation with increased accuracy.

To measure the roundness, images are captured during the movement of the rotary axis. From the images of the various rotational positions, measurement points are determined in each case, which are then calculated to form a circle. With up to 400 measuring points per second and measurement errors in the range of 200 nanometers, the accuracy of form measuring machines is achieved with significantly less measuring time.

Thus, Werth coordinate measuring machines on a new performance level enable the solution of measuring tasks, which could not be performed on conventional coordinate measuring machines so far.