脉冲MIG焊熔滴过渡阶段波形控制研究

在自行研制的软开关逆变电源上改变脉冲MIG焊控制波形，在电流波形的下降沿增加熔滴过渡阶段，实现焊接过程的稳定可控。通过小波分析仪采集并统计了瞬时电流、电压、动态电阻、瞬时能量、概率密度分布等数据，对焊接过程进行了客观分析和评定。实验结果表明：增加熔滴过渡阶段有助于实现焊接过程的稳定可控。过渡电流较小时，能量不足，易出现短路过渡，焊接不稳定等现象；过渡电流接近峰值电流时，焊接情况与普通脉冲MIG焊类似，达不到波形控制目的。过渡电流不变，焊接质量随着过渡时间的增加而提高，当焊接时间为7ms时焊接效果理想，随着时间的进一步增加，过多的能量使熔滴过渡不规则，焊接质量开始降低。熔滴过渡电流为160A、过渡时间为7ms是本实验条件下的最佳工艺参数。

Waveform Control of Metal Transfer in Pulsed MIG Welding

Against self-developed soft-switching power inverter, the stability and controllability of welding process is realized through adding metal transfer phase during the failing edge of pulse waveform. The data of instantaneous currents, transient voltage, dynamic resistance, instantaneous energy and probability density distribution are acquired and analyzed by wavelet analyzer. The welding process is also tested and analyzed by wavelet analyzer. The results show that adding metal transfer phase contributes to the stability and controllability of welding process.When metal transfer current is too small, short circuit transfer happens frequently and the welding process is not stable due to energy shortage.While the current is close to the peak, the welding process is similar to ordinary pulsed MIG welding , which is deviated from the goal. When the current is given, welding quality is improved with the increase of metal transfer duration and the welding process is ideal when metal transfer duration is 7ms. But welding quality becomes lower if the metal transfer duration continue to increase because excessive energy makes metal transfer irregular.160A of metal transfer current and 7ms time of metal transfer duration are the optimal matching parameters under this experiment conditions.