Weld inspection process improvement

Abstract

This project addressed challenges within the weld inspection process in one factory at Caterpillar through the implementation of phased array ultrasonic testing. The chosen factory fabricates and machines large weldments for track-type tractors. The industry trend towards lighter weight, lower cost, higher performance structures requires greater confidence in weld quality than can currently be ensured with existing inspection methods in use at Caterpillar. Previous attempts to implement phased array technology in production factories at Caterpillar were unsuccessful due to the perceived costs of the technology, a lack of training, a lack of internal standards, and a lack of a change agent. The first step in the project began with understanding the current state of weld inspections. This was accomplished through factory visits, as well as interviews with -vendors and Caterpillar's non-destructive evaluation community. Statistical analysis of quality data was conducted to understand current welding and inspection performance. This revealed several problems with the process that led to inaccurate inspection results and unnecessary factory rework. Next, the project identified a pilot case to introduce the phased array technology. After acquiring the necessary phased array equipment, a robust, repeatable, cost effective process was developed where data is stored, and can be recalled and used to improve quality and future designs. Necessary fixtures were prototyped and tested to demonstrate the value of implementation. The implementation phase focused on training the operators to use the new equipment and procedures while still ensuring that the quality of parts released downstream was not compromised. The final phase of the implementation validated the quality of the inspection data and focused on improving the speed and safety of the phased array ultrasonic inspections. This project integrated phased array ultrasonic testing into a factory and provided a framework for Caterpillar to continue to develop and deploy this technology across the enterprise. By identifying and solving gaps in the technology rollout process in collaboration with Caterpillar's non-destructive evaluation community, this project created positive change in the culture and execution of how improvements are made to weld inspection processes.