Abstract
A workpiece produced by die-casting or other casting process has a relatively low level of accuracy. Thus, finish machining is often required for such workpieces. However, it is difficult to set up a workpiece in the designated position with the work holding table. To easily make cutter paths for the workpiece in the designated position, this paper proposes machining operation method. This relies on coordinating the workpiece and cutting paths to make it easy to find the correct position. In this study, reverse engineering is used to obtain the 3D model of a workiece. The model is scanned by a 3D laser scanner. The 3D lattices point data were then constructed by interpolating and thinning the scan data. The RANSAC method is applied to primitive shape recognition for unorganized point clouds to detect planes, cylinders and spheres. The system also recognizes primitive shapes: namely, planes, cylinders, and spheres, from the STL data and match the scan data with STL data. After fitting, the system can know the position of workpiece and the machine tool table. Thus, the position can be used to set the origin of coordinated workpiece and cutting tool path for the machining operation can be generated.
