Lead measurement of ground shaft surfaces with the 2D roughness antenna
Dr.-Ing. Albrecht Hertzsch
Value for the audience
Vorstellung eines neuen optischen Messverfahrens zur Drallbestimmung
Bewertung von Oberflächen, die als Dichtungsgegenlaufflächen eingesetzt werden sollen
Auswirkung unterschiedlicher Herstellungsverfahren auf die Oberflächenrauheit
was ist Mikrodrall und was ist Makrodrall
die 2D-Fourieranalyse zur Bestimmung von Oberflächentexturparametern
Summary
Based on the optical 2D speckle measurement, a method and a sensor are presented that records and evaluates the roughness in two dimensions with high lateral resolution. With this measuring method, scanning frequencies of up to 1Mhz can be achieved, enabling twist measurements in the minutes to seconds range. For the first time, even very large shaft diameters (D > 1m) can be scanned and the roughness texture can be determined in a statistically stable manner with angular minute accuracy. The sensor is designed as a mobile measuring system and can be used directly in the machine of the grinding machine or lathe. With two integrated measuring axes, the measurement data is recorded autonomously on the uniformly rotating test shaft. A key component of the process is the frequency-based evaluation of the measurement data with a process-optimised evaluation routine. This includes algorithms for determining the test part-related coordinate system, the coordinate-compliant alignment of the measurement points, the eccentricity correction of the measurement data, the diameter-dependent segmentation into partial data sets and the calculation of statistically stable parameters for the texture analysis of the roughness.
New evaluation models based on the fast Fourier transformation were introduced, tested and validated for both the texture angle calculation and the calculation of the conveyor cross-section differences.
The sensor is suitable for both macro and micro twist analysis.
Measurement examples on typical production sealing surfaces are presented and discussed. The accuracy of the measurement method is demonstrated using reference measurements with a scanning profilometer.