脉冲MIG焊建模仿真分析及弧长控制

Modeling,Simulation Analysis and Arc Length Control of Pulsed MIG Welding

针对脉冲MIG焊过程中的电弧稳定性问题,建立基于尖端不稳定熔滴过渡理论的焊丝熔化动态电弧模型,并对焊接过程中的电弧电压、电弧长度及熔滴过渡尺寸进行仿真,得到与实际焊接相似的电弧电压波形,分析脉冲电流下熔滴过渡频率及影响电弧稳定性的因素,且进行弧长稳定控制的仿真研究,在此基础上运用快速原型技术建立铝合金脉冲MIG焊控制系统,采用电弧电压反馈对铝合金脉冲MIG焊过程进行送丝调节的弧长控制试验。研究表明:所建立的铝合金脉冲MIG焊焊丝熔化动态电弧模型很好反映了实际焊接过程,揭示出脉冲MIG焊焊接过程中熔滴过渡时间间隔具有一定的不确定性和电弧长度的不稳定性,通过电弧电压反馈控制可显著改善铝合金脉冲MIG焊过程电弧系统的稳定性。

In order to solve the problem on arc stability of pulsed MIG welding,wire melting dynamic arc model based on the theory of cutting-edge droplet transfer instability is established,and welding arc voltage,arc length and droplet size in the process of welding are simulated.Arc voltage waveform obtained by simulation is similar to actual welding.Droplet transfer frequency under the pulse current and the factors affecting arc stability are analyzed.Then simulation of arc length stability control is conducted.On this basis,control system for pulsed MIG welding of aluminum alloy is built with rapid prototyping technology,and then arc length control test is carried out by adopting arc voltage feedback.The results show that wire melting dynamic arc model of pulsed MIG welding reflects the actual welding process well.The uncertainty of metal transfer intervals and the instability of arc length can be improved significantly through the control.