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激光金属沉积(LMD)传统上多采用固定的工艺参数进行扫描堆积成形,每层的实际堆积高度一般是固定且不可控的。为提高成形稳定性和成形件的精度,补偿堆高误差,开发了一种可实时变化工艺参数的堆高闭环控制系统。通过反馈实际堆高与设定期望层高之间的误差,控制实际堆高达到设定值。设计P和PI两种控制器,分别以扫描速度和激光功率作为输入参量来控制实际堆高。结果表明,变扫描速度控制优于变激光功率控制,实际层高的最佳稳态波动范围可达±0.015mm;PI控制器可使总堆高达到期望值;当送粉速率发生突变时,P控制系统具有良好的鲁棒性;P控制器的阶跃响应曲线与成形件剖面纹理显示的堆高变化一致。该系统为堆高的可控和堆高误差补偿提供了新方法。
Traditionally, laser metal deposition (LMD) has been deposited using fixed process parameters for scanning deposition. The actual stacking height of each layer is generally fixed and uncontrollable. In order to improve the forming stability and the precision of forming parts and compensate for pile height error, a high closed-loop control system for stacks with real-time process parameters has been developed. By feeding back the actual pile height and set the expected height between the error, control the actual pile height up to the set value. Design P and PI two kinds of controller, respectively, the scanning speed and laser power as input parameters to control the actual pile height. The results show that the variable scanning speed control is better than the variable laser power control, the optimal steady-state fluctuation range of the actual floor height can reach ± 0.015mm; PI controller can make the total reactor reach the expected value; when the powder feeding rate changes suddenly, P The control system has good robustness. The step response curve of the P controller is consistent with the height change of the profile shown by the profile. The system provides a new method for stack height control and stack height error compensation.