STEPNC++ - An Effective Tool for Feature-based CAM/CNC

This chapter discusses the realization of direct translation of feature-based CAM files into feature-based CNC part program files. The information infrastructure that allows this to happen is STEP-NC, as described by ISO 14649 Parts 10 and 11. Among the many benefits cited for STEP-NC, the elimination of the costly and inefficient process of post-processing using one standard CNC definition is most commonly cited. However, this chapter argues a much greater benefit can be found using STEP-NC to resolve the CAM/CNC impedance mismatch where CAM comprehensive process information is reduced into motion primitives. The CAM/CNC impedance mismatch and resulting lack of process information make intelligent machining difficult. Given this perspective, a demonstration system was developed to show that feature-based CNC is possible with STEP-NC, which preserves more featurebased CAM process knowledge to make intelligent machining possible. The demonstration system incorporates: 1) part representation using STEP-NC Part 21 files, 2) reading and analyzing feature-based elements of the STEP-NC, 3) translation into a CNC feature-based representation, and 4) generation of actual CNC programs relying on conversational programming “Canned Cycles”. Cutting and simulation tests have confirmed the advantages of the approach. Overall, the demonstration system shows a standard information infrastructure such as STEP-NC is essential for advancing manufacturing to enable improvements in efficiency, product quality, life-cycle cost, and time-to-market.