Challenges and Choices in the Specification and Implementation of the STEP-NC AP-238 Standard

Abstract

STEP-NC AP-238 is the result of a ten-year effort to replace the RS274D (ISO 6983) M and G code standard with a modern associative language that connects CAD design data to CAM process data. STEP-NC builds on previous work to develop a neutral data standard for CAD data and uses the modern geometric constructs of that standard to define device-independent tool paths, and CAM-independent volume removal features. This paper describes four key factors, or challenges, that had to be addressed to extend STEP-NC AP-238 functionality beyond that offered by other CNC standards. The four factors are difficulties inherent in all CAD/CAM integration projects and can be summarized as follows: the information complexity of geometry, the volume of attributes defined for manufacturing processes, the difficulties of integrating models that span CAD and CAM, and the requirement for easy implementation. We describe an advanced CNC application that uses these four factors and show how STEP-NC AP-238 enhances CNC machining and measurement.

Development of STEP-NC Based Manufacturability Evaluation System

“…Since numerical control technology was developed about 60 years ago, it has undergone significant changes to an extent that high-speed machining with ultra-high precision has become possible [1]. However, the current CNC language, so called G & M codes formalized by ISO6983, is a low-level language that delivers only limited information to CNC and is considered as unfit for shop-floor programming purposes.…”

STEP-Based Feature Modeller for STEP Compliant CNC

“…Since numerical control technology was developed 50 years ago, it has undergone significant changes to an extent that high-speed machining with ultra-high precision has become possible [1]. However, the current CNC language, so called G & M codes formalized by ISO6983, is considered as a low-level language that delivers only limited information to CNC and is unfit for shop-floor programming purposes.…”