# Research of a Multi-Frequency Waveform Control Method on Double-Wire MIG Arc Welding
## 6 Conclusions and Future Works  
In this work, a new current waveform control method for double-wire MIG arc welding was proposed to improve the stability of welding process and the quality of welding seam. During the welding process, the mutual electromagnetic force between two electrical arcs may induce some abnormal phenomena, such as arc interruption, irregular metal transfer or considerable expulsion. To obtain a stable welding process and welding products with satisfactory quality, a multi-frequency modulation was added to the trailing wire current waveform under the situation that the two wires currents waveforms had the same frequency but inverse phases. This new conduction can improve  
Figure 14: Weld surface under the optimized parameters.  
Figure 13: Pdf under the optimal parameters combination.  
the welding seam formation, decrease the possibility of arc interruption appearing, and improve the heat efficiency. Then, actual experiments were conducted to validate the method by our self-designed platform and other relative facilities. During the process, orthogonal experiments and corresponding analysis method were employed to seek an optimal parameter combination. As for the four important parameters, the number of high frequency modulation pulses \(N_{fTH}\), duty cycle of trailing wire high frequency modulation pulse \(DC_{TH}\), duration of leading wire current in base value \(T_{BL}\), and peak current of trailing wire \(I_{pT}\), it can be seen that the first parameter was the most important element to determine the welding quality, then the following is \(I_{pT}\), and the effects of other two parameters were relatively smaller. The optimal parameters combination were employed and final experimental results showed that the satisfactory welding seam can be obtained. The welding seam was so beautiful and no abnormal phenomenon occurring during the process, which showed that the proposed multi-frequency waveform control method and corresponding analyses can achieve satisfactory performance in actual application.  
In the future, we will continue working to seek more reliable methods to improve the proposed method; for example, other parameters can be added to explore how they affect the stability of the process and the quality of welding seam. Moreover, we will also try to apply this new method to other welding processes, such as metal active gas (MAG) welding process, and improve the current operation. In addition, the analysis method in this work can be simplified and the optimal parameter combination can be quickly confirmed for each case.  
The authors would like to thank the Foundation for Natural Science Foundation of Guangdong Province (2015A030313663), National Natural Science Foundation of China (Grant No. 51605103), Public Welfare Research and Capacity Building Project of Guangdong Province (2015A010104010), Characteristic innovation project of Guangdong Province Ordinary University (2014 KTSCX145) and China Postdoctoral Science Foundation (2016M602461).  
In this work, [PERSON] proposed the method and designed the experiments, [PERSON] optimized the method and corresponding experimental programs. Then [PERSON] conducted the experiments. Finally, [PERSON] and [PERSON] collaboratively analyzed the experimental results and accomplished the paper written.  
The authors declare no conflict of interest.