Integrated Interface System of STEP Data Models for the Tool Path Generation

Abstract

The STEP (STandard for the Exchange of Product model data) is a worldwide standard for exchanging products between diverse computer systems and industrial applications. STEP file contains 3D data in the universal data format (ISO 10303-21) structured in boundary representation (B-rep) methodology. It has the potential of exchanging data models between CAD/CAM and CNC systems for generating tool paths in G-Code (ISO 6983) format. However, the complexity of STEP models is a significant challenge for wider use. Conventionally, G-code generation currently uses CAM software as an add-on, and it entails high installation costs. Also, this software usually only embraces a particular CAD design format. The development of the integrated interface system for CNC machining provides an alternative to G-code generation by bypassing CAM software in modern manufacturing systems requiring a potential advanced computer controller in the future. This research discusses the design, implementation, development, and testing of the Integrated Interface System (IIS) using the knowledge discovery approach. This system can generate Geometric Code (G-Code) based on ISO 6983 and provide tool path generation for machining operation using STEP files as input. The system provides the function to read and extract the STEP file's relevant information that eventually writes a G-Code file format as an output file related to machining data. The Geometric Data Extraction (GDE) algorithm has been used to identified feature information, recognize various strings, and interpret them in G-code terms for CNC programming. A geometric data processing algorithm is designed and developed into a computer interface. The sample block consisting of geometric features is modelled from a 3D CAD model and saved in STEP file format. The machining process is carried out by milling the sample parts using the generated G-codes using Mach4 as a PC based CNC controller. The result tested through machining simulation using a CNC simulator and simulation in the Mach4 software. The validation process is performed by comparing the CAD design feature, the simulation result, and the machining process's end product.