位控模式下的凸焊预压力变化分析及影响

Analysis and Effect of Projection Welding Preload Changing under Position Control Mode

研究了凸焊设备的位控模式和预压力参数波动原因,量化分析了压力参数变化范围;采用定电流和时间参数改变电极压力参数的方法进行了凸焊实验,使用微电脑拉力试验机测试焊点焊接强度,基于实验结果用MATLAB拟合预压力与焊点强度的高次曲线。基于拟合曲线确定实验电流、时间参数下的最佳预压力,结合实验拟合曲线和量化的压力参数浮动范围得出压力浮动造成的焊点结合强度降低范围;提出转矩控制方式控制预压力,以消除电极压力浮动造成的焊点质量不稳定。

The preload of the automatic projection welding equipment under position control mode changes over time and affects the stability of the welding quality.The position control mode of the welding equipment and the reasons of pressure fluctuations were studied;the range of preload was calculated;with current and time parameters fixed and preload changed,experiments were conducted,then welding strength was tested by micro tensile testing machine;curves of preload and bonding strength were fitted with MATLAB based on the results of experiments.Under the fixed current and time conditions,the best welding preload was found according to the fitting curve,and the reduce of the bonding strength was determined too;at last,the torque control mode was proposed to eliminate the unstable welding quality caused by the change of preload.