Study On Numerical Control Welding System And Technology Of Quality Evaluation For Irregular Workpieces

To alleviates the problems such as fund insufficiency, the weak ability to use the advanced equipment and the poor purchasing power in small and medium-sized enterprise, it is very important to research and develop the special numerical control system to satisfy the welding of irregular workpieces. In this paper, we used the modularized and distributional system structure with the embedded micro-controller used as central observation and control unit, introducing visual sensing system and technology of image processing in information feedback link to obtain and control the dynamic characteristic parameters of weld pool in welding process in real-time. Finally, a set of welding numerical control system for irregular workpieces with the significant characteristics of low production cost, stable welding quality, and simple operation was developed. In addition, The assessment technology of welding quality was also discussed. The details were arranged as follows:Chapter 1, the present research of welding automation and assessment technology of welding quality technology were introduced briefly. At the same time, the significance and contents of this study were presented.Chapter 2, the overall plan of the welding numerical control system for irregular workpieces based on the special application was described in this chapter.Chapter 3, the key problem -digital image processing in the extraction of dynamic characteristic parameters of weld pool had been systematically discussed. Three detailed methods (image pre-processing, edge detection and dynamic geometry characteristic parameters of weld pool) were proposed to solve this key problem.Chapter 4, the key problem in evaluation of welding quality was studied based on the improvement of SNR for echo in non-destructive ultrasonic detection. And finally, a new method was proposed to improve SNR for ultrasonic echo and used to solve the problems such as welded joint flaw in the evaluation and uncertainty of welding quality efficiently.Chapter 5, the system structure was analyzed firstly and the integration of the system was completed from both hardware and software.Chapter 6, the contents of the whole paper was summarized and the future research of the numerical control system for welding irregular workpieces was forecasted.