机器人等离子熔射路径参数对涂层温度分布影响

Influence of trajectory parameters on the coating temperature distribution in robotic plasma spraying

结合红外测温仪与机器人熔射路径对基体/涂层温度分布进行连续在线检测,提取周期温度均值和标准差对检测结果进行表征.据此实验研究了机器人Z字形路径参数,包括熔射距离、扫描间距与速度对涂层温度分布的影响.结果表明:扫描速度对周期温度均值变化没有影响,扫描速度的选择应优先考虑周期温度波动;涂层周期温度标准差随扫描间距的增加而减小,但是周期温度均值变化取决于射流/粒子流对基体/涂层的作用时间;周期温度均值和标准差均随熔射距离的减小而增大.

An on-line and in-situ investigation approach for the temperature distribution measurement of substrates and sprayed coatings is presented, based on IR pyrometery combined to a specific robot scanning trajectory. Two key factors, the periodic average temperature and the periodic standard devi- ation, were adopted to evaluate the temperature variation and the fluctuation of the thermal cycle rele- vant to one robot spraying cycle. Moreover, the influence of processing parameters of robot spray trajectory, including spray distance, scanning velocity and scanning step on coating temperature is experimentally studied and explained reasonably through the comparison of the two factors. Experimental results show that average temperature has no evident difference as a function of scanning velocity and no fixed correlation observed with scanning step, but just is dominated by the heating time of plasma jet and particle flux. Therefore, the choice of an optimal scanning velocity just needs to take account of temperature fluctuation. The temperature fluctuation decreases with the increasing of scanning step, but both average temperature and fluctuation decrease with the increasing of spray distance and vice versa.