Validating Portability of Step-nc Tool Center Programming

A joint effort between Boeing and the National Institute of Standards and Technology (NIST) was undertaken for validating and evaluating STEP AP238 (STEP-NC) Conformance Class 1 (CC1) for 5-axis machining. STEP-NC is a new manufacturing standard to support “design anywhere, build anywhere, and support anywhere.” The joint Boeing/NIST validation intended to prove that five-Axis AP-238 programs with tool center programming (TCP), as opposed to that of axis movement data, are portable. Current RS274 “G code” part programs that use axis movement data are bound to a single CNC, are ineffective on different machine tools, and cannot be used for the exchange of information between process planning, work preparation, tooling, and other production processes. All of these obstacles add considerable time and cost to the production life cycle of a machine part. This paper discusses the joint Boeing/NIST STEP-NC TCP validation work. The major findings were that STEP-NC TCP geometrical data is portable across different 5-axis configuration CNCs. This came with a caveat, that although CNC programs can be “data-neutral”, they are not necessarily “processneutral”.