Automatic Spot Welding Feature Recognition from Step Data

Abstract

In design and manufacturing many systems are used to manage technical product data. Each system has its own data formats so the same information has to be entered multiple times into multiple systems leading to redundancy and error. Generic format is needed to overcome this misunderstanding. Geometric models with complete design data details are created through CAD software and translated into an equivalent boundary representation(B-Rep) format in the form of neutral file. These neutral files can be transported for further analysis or process planning. Automatic feature recognition is the process of significant information extraction from neutral file and identifying the welding features without any human intervention. Automatic feature recognition is an important aspect for CAPP and it is an important task between CAD and CAPP. CAPP is the bridging gap between CAD and CAM. Automated feature recognition is considered a critical node for integration of CAD/CAPP/CAM. Research in feature recognition has received significant attention, however, the majority of feature recognition systems are for machining features. Present work is an attempt to develop a method for automatic feature recognition of spot welding from neutral file, STEP (AP203). which is an international standard for geometric and non-geometric data transfer between heterogeneous systems. This study explains the software Development in Python language for feature recognition which work as an integration between CAD and CAPP. The system developed uses a simplified and generalized methodology of extracting spot welding feature information from STEP files. Three dimensional Assembly with multiple spots weld created by using Creo 3.0 software to recognize features. Three main features of Spot welding are highlighted (1) Total Number of spot welds (2) Coordinates and Diameter of each spot weld (3) plane of weld. Rule based technique is used for recognizing features. The software has been implemented and tested on several components. The results are satisfactory and successful. An illustrative case studies is presented to test and validate the method.