Closed-loop CAPP/CAM/CNC process chain based on STEP and STEP-NC inspection tasks

The object-oriented STEP-NC programming interface supports a bi-directional data exchange between computer-aided manufacturing (CAM) systems and computerized numerical controllers (CNCs), and by that helps to integrate the CNC into the CAx (Computer Aided technologies in general) world. In this context the current paper introduces the integration of measuring technology into the STEP-NC-based process chain, to be able to preserve the results of the manufacturing process in a set of data and feed them back to the planning process. In particular this paper describes the current draft of ISO 14649 part 16 (Data for touch probing based inspection), which allows the integration of inspection tasks into a sequence of machining operations. It gives a short overview of how part 16 fits in with other inspection data exchange standards and draft standards, such as STEP AP219, dimensional measuring interface standard (DMIS), dimensional markup language (DML) and I++DME. Furthermore, a prototype demonstration scenario for the closed-loop process chain is presented, which includes generation and execution of a STEP-NC program and feedback of measured results, achieved by automatically controlled STEP-NC inspection tasks, to the CAM system.