Real-time adaptive wire feeding in pulsed micro-plasma arc welding based on rapid prototyping system

The impact of the droplet transfer process and the wire feeding direction on the deposited track's quality of the direct metal rapid prototyping using pulsed micro-plasma arc welding (PMPAW) is researched. The results show that the smoother deposited track can be deposited with the bridging transfer. Constant wire feeding direction during the deposition process brings on some defects, for example, partial droplet does not melt into molten pool and filler wire is interfered with the solidified deposited track when some tracks have larger angle with wire feeding direction. An adaptive wire feeding subsystem that can adjust the wire feeding direction based on the part's section contour in a real-time mode is developed to avoid the defect and the interference. The algorithm of angle, resultant velocity and acceleration is expatiated. Some experiments are carried out to compare the deposited track's qualities of different wire feeding modes. The results show that the adaptive wire feeding system can avoid the deposition defects and interference and ensure the deposited track's quality obviously.