Laser scanning probe with multiple detectors used for sculptured surface digitization in reverse engineering

This paper presents a single-point laser probe with multiple detectors for scanning of a sculptured surface for digitization by reverse engineering. The probe consists of a point laser source and four linear high-resolution PSDs (Position Sensitive Devices). Its target scanning distance is 180 mm from the probe to the measured surface, with a measurable range of 90 mm. Assuming a diffusive surface, the displacement from the light spot on the measured surface to the probe along the light-axis can be derived by the Lambert model. In addition, the inclination angle of the measured point from the vertical axis of the light beam is also calculated. In this study, the probe is mounted on the NC machine integrating the three-axis controller, personal computer and A/D card to conduct the digitization process. Functions of the probe are verified by a standard half-sphere model. The test results show that the displacement resolution is reaching 50 μm and the measurable range of the inclination angle is 80 degrees. A mask model is digitized to demonstrate the scanning results