Feature-based off-line programming of coordinate measuring machines

The paper describes an off-line programming system for coordinate measuring machines based on a novel approach. Input data to the system is the geometric model produced by a CAD system. Using the picture of the part, the user can select the surface elements to be inspected. He or she has to provide the tolerance data as additional information. First the workpiece setup is decided: the position, orientation, and accessibility of the part is determined. Next the system automatically generates an optimal distribution of the measuring points for the surfaces to be inspected and the local probe path. Probe clusters are built together on an interactive way using a set of building blocks. A time optimal sequence of the inspection operations is computed using heuristic algorithms. At this stage all information needed for the CMM program is available and will be combined in a device independent DMIS format, which in turn can be converted into equipment specific programs.