Simultaneous control of torch aiming and deposition rate to groove gap with high-frequency oscillation arc sensor. Development of high-frequency oscillation arc (Report 3)

摘要

Based on the new arc sensor for simultaneous detection of torch aiming deviation and gap width, this paper describes an investigation of a welding parameter adaptive control system that keeps the leg length constant irrespective of groove gap fluctuations and proposes an automatic welding control system using the welding speed as the constant leg length control parameter. Welding tests are conducted to validate the effectiveness of the newly developed automatic welding control system. The paper further outlines the development of a compact portable carriage-type automatic welding system incorporating the high-frequency oscillation arc method and automatic welding control system. The results obtained may be summarised as follows:The proposed arc sensor based on the high-frequency oscillation arc method is capable of simultaneous detection of the groove gap and torch deviations in the vertical and transverse directions.To stabilise horizontal fillet weld quality characterised by groove gap fluctuations (i.e. to maintain a constant leg length), it is effective to control the deposition rate using the welding speed as the constant leg length control parameter. The relationship between the groove gap and welding speed necessary for adaptive control is accordingly established.The automatic control system based on the proposed arc sensing method is able to perform simultaneous control of the welding speed by detection of torch aiming (seam tracking) and the groove gap and enables a stable weld quality to be obtained under fluctuating groove gap conditions.A compact carriage-type automatic welding system incorporating the automatic control system based on this method is also developed. The system is compact, light-weight, and portable, widens the torch operating range, and is effective for automation of welding performed in confined spaces.