Automatic modeling workpiece map using camera and projector for automatic workpiece alignment aid of CNC machining

Abstract During CNC machining, one of the most critical and complex tasks is the establishment of the workpiece coordinate system (work offset), which is typically performed using a tool probe setter. In current industrial practice, this procedure is largely dependent on skilled operators. However, manual operations are prone to human errors, such as incorrect data input or improper probe handling, which may lead to damage to the probe, machine components, or the workpiece. In addition, the accuracy and repeatability of workpiece alignment within the machine coordinate system are essential for ensuring product quality and machining consistency. This study proposes an automatic calibration system for workpiece coordinate setting at the machine home position based on 3D modeling and structured light scanning. The proposed system employs a Gray-code-based structured light method to reconstruct the 3D geometry of the workpiece and to identify edge coordinates for automatic adjustment of the work offset via an optical probe. Experimental results demonstrate that the reconstructed model achieves a dimensional error within ± 0.1 mm, while the positioning error based on point cloud edge detection is within 0.05 mm. These results validate the effectiveness and accuracy of the proposed automatic alignment system.