A novel pretreatment method for chamfering contour error in subsea multifunctional operation equipment

Subsea multifunctional operation equipment can complete: i) anticorrosion layer removal of the pipeline, ii) drilling and cutting off pipes, iii) inside/outside chamfering of pipe ends, and iv) removal of weld line in underwater operations. In the chamfering operation, there are problems like: i) high cutting force, ii) contour error and iii) serious tool wear. These are caused by: i) the non-concentricity among the self-centering pipe clamping device, and ii) the cutter head and the pipe center. In this paper, a contour pretreating method is developed to predict the pipe center and chamfering contour error. In this method, self-centering clamping device, cutter head and pipe center are not concentric, and the eccentric coordinates of the pipeline center was derived through the three points on the contour line of the pipe detected by the laser sensor installed on the multifunctional operation equipment. Then standard operating position was adjusted to calibrate the difference between the standard position and the position of any other angle was the contour accuracy deviation. In the chamfering process, the cutter head is preprocessed by the contour error correction program to achieve the goal of eliminating the contour error. The subsea multifunctional operation equipment finished the chamfering experiment on 18-inch pipe end of submarine pipeline, and the experimental results validated the effectiveness of the contour error pretreating method. The method defines the relationship between the self-centering clamping device and the eccentric error of the pipe, and makes a timely correction to the contour error of pipe end groove. This solves the problem of non-uniform chamfering caused, and provides technical support for underwater chamfering operation of the equipment. © 2016, UK Simulation Society. All rights reserved.