Development of the PC-based Integrated Interface System of STEP file for CNC Machining Application: Circular Features

Abstract

STEP is a general data format that observes the international standard ISO 10303-21. STEP means Standard for the Exchange of Product model data. It consists of the 3D geometry of a computer-aided design (CAD) model in the configuration of boundary representation (B-rep). By extracting, refining and decoding the geometric data correctly, the data can be utilized for writing G-code for Computer Numerical Control (CNC) machining application. Usually G-codes can either be manually generated by skilled machinists or automatically generated by computer-aided manufacturing (CAM) software. However, manually generated G-code is inefficient and susceptible to error. Meanwhile automated generation G-code requires significant setup cost. This paper describes the design and development of an integrated interface system, an instrument aimed to be used to analyze STEP files and generate machining tool path based on ISO 6983 format. This developed interface reduces the need for high setup cost as well as eliminates human limitations. The interface at present is able of detecting circular machining features on the workpiece. Circular machining features are created by 3D modelling software and retained as STEP file. The STEP file which contains geometrical data is then uploaded to the interface system as an input file which is structurally analyzed and processed. Finally, the ideal machining tool path in the G Code format is proposed and generated. By bypassing the CAM software and its proprietary post processor, the outcome of this research is important to enhance compatibility between different CNC machine systems

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

“…During the read/write/rewrite module stage, the interface will analyze all data information in the STEP file line-by-line. Each analysis will yield the final result, which contains the cartesian point for x, y, and z representing the coordinate readings to generate the machining tool path and G-code [19]. The following STEP file will be implemented into the extraction module, analyzing each line.…”

Milling Features Recognition Methodology of Rectangular Fillet Blind Pocket for Universal Data Structure

“…This is due to the more features added to the model, the B-rep model will encode more geometric information such as more information about the geometric data and topological data. The details of geometric data and topological data are documented in Sharizam et al, [7].…”

“…Many types of research had been done regarding automatic feature recognition of STEP files such as linear features [6], circular features [7] and the latest studies involving full profile features (a combination of linear features and circular features) [8]. However, they only focus on Cutter Location (CL) which eventually describes the machining profile in the x and y plane without considering the depth of the machining feature in the z-axis.…”

G-code converter using interface system for a STEP file (ISO 10303)

“…This interface primarily reads STEP files generated by CAD software, which are computer-generated images of machined blocks derived from blank workpieces. The interface processes the STEP file, extracting geometric data to determine tool paths and generate G-code after scanning [18]. By reading and processing all instances within the STEP file, only the necessary information for programming output is extracted.…”