X. Weisheng, Z. Haiou, W. Guilan, Huazhong University of Science and Technology, Wuhan, China
Coating damages, such as cracks and peeling always occur with high temperature gradient and resulting residual stress level, so it is important and necessary to monitor and control the coating temperature during the process of atmosphere plasma spraying. In this paper, substrate and coating temperature were on-line monitored by IR pyrometer combining with special robot scanning mechanism in order to avoid the influence of spraying environments and plasma jet. Then the temperature-time evolution was recorded and two specific factors, temperature mean and standard deviation were adopted to evaluate the temperature variation and fluctuation of the thermal cycle corresponding to one robot scanning cycle based on the statistical method. Meanwhile, the two factors were successfully proved to be able to exhibit the temperature variation by the processing experimental sets. Finally, on the basis of experimental results of the influence of Z typed robot spray trajectory parameters, such as spray distance, scanning speed and space on the two factors, the intelligent adaptive control of sprayed coating temperature was developed to keep the temperature fluctuation of thermal cycles on the help of switching of robot trajectory, holding of spraying and so on. Actual running has shown the system had a good performance.
