Ultrasonic-driven adaptive robotic plasma cutting system for hole cutting applications

Abstract The manufacturing of circular holes in thick steel plates in the shipbuilding and oil & gas industries requires heavy cutting manufacturing processes. The process of plasma arc hole cutting in thick steel plates faces challenges in achieving precise diameter quality due to operators’ mistakes and plate thickness tolerances. The current standard approaches rely on operator skills and manual parameter settings, which lead to inconsistent hole dimensions and the existing of dross, which requires a rework process to meet dimensional requirements. The proposed ultrasonic-driven adaptive approach uses pre-process real-time ultrasonic sensing to measure actual plate thickness automatically, which enables the system to adjust its cutting speed parameter and path planning for circular hole cutting. The approach performs an initial ultrasonic scan of each hole before it adjusts both tool paths and cutting speed parameters according to the detected material thickness. The adaptive approach delivers improvements in cut precision and reliability, which enables smart manufacturing operations to achieve Industry 4.0 targets. The results show near-cylindrical shapes output cut quality for entry and exit diameters with a reduction in entry diameter deviation exceeding 80%, while the exit diameter deviation was also reduced with improvements ranging from 37% to 46.3% compared to the standard cutting approach. Also, regarding entry ovality deviation, the proposed adaptive method demonstrates a reduction between 56.2% and 72.7% compared to the standard approach, confirming improved circularity of the produced holes. The research demonstrates how using an ultrasonic sensor for the automation of the robotic plasma arc hole cutting approach in steel plate leads to better results and increased adaptability.