The Detecting And Analyzing System Online Of Welding Quality Based On Labview

Welding processing is changable continuously and unstable, welding quality is related to many welding parameters, but it is effected by welding current and arc voltage mostly and as welding current and arc voltage are easy to be collected and controlled. this paper regards welding current and welding voltage as the analyzing signal, design a collecting and analyzing system for welding quality based on visual instrument LabVIEW8.6,it can be used to analyze stability of welding process and the possibility of spattering,and it help to assess the performance of welding equipment and welding consumer, besides, it can be used study the relation between arc voltage and short-circuit frequencyThe system consists of hardware part and software part, the hardware part involves PC, data acquisition card and Hall sensors of voltage and current; it used to implement the signal of arc voltage and welding current and obtain the digital signal that can be recognized by PC through the A/D transform,software part is mainly to program based on the LabVIEW8.6,throght these programs, the signal can be collected as we needed, transformed, saved and analyzed.The software of this system consists of the collecting part and the analyzing part,the signal sample of voltage and current can be collected,waveforms can be showed,date can be saved and welding testing parameters can be made a record in the collecting part,in the analyzing part, the data can be analyzed in the ways such as filter and playback,U-I carve,arc power, fisrt-order differential, correlation, frequency domain, probability of density and short-circuiting frequency. whether the process is stable can be judged by the curve we got and the Statistics such as average short-circuit time, average short-circuit current, and their standard deviation and varianceIn addition, the relation between each welding parameter and short-circuit frequency can be studied by this system,at first,those short-circuit frequencies are calculated by many tests in which the arc voltage or welding velocity is changed every time,and then the U-F curve and V-F curve can be fitted by the fitting function of the system, so we can obtain the best arc voltage and welding velocity throught these curves to guide the welding production and ensure the welding quality.To evaluate the stability and the accuracy of this system, three experiment be designed, they are the stability experiment when adapting the different welding parameters, the experiment of assess the dynamic characteristic and the studying experiment between each welding parameters and short-circuit frequency. these experiment have demonstrated that this system can evaluate the stability of welding and the possibility of spattering effectively to some extent. and offer the theorial guidance for the welding production.