Automatic recognition and control of welding arc morphology as a function of the welding current and the tungsten electrode height
ZHU Zhiming, CHENG Shijia, YU Yingfei, FU Pingpo
Key Laboratory for Advanced Materials Processing Technology of Ministry of Education, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
Abstract：A welding arc has very different geometric morphologies depending on the welding process parameters that can change during the weld. High speed photography and image processing were used to develop a discriminating model to evaluate the arc morphology while welding using a polar coordinate system. The model was then used to study the quantitative relationship between the arc morphology and the tungsten electrode height for various welding currents. The experimental results show that various welding currents and tungsten electrode heights lead to four typical arc morphologies with oblate conical shapes, bell jar shapes, long conical shapes and long strip shapes. The range of tungsten electrode heights corresponding to each arc morphology were found to vary for different welding currents. With the bell jar shaped arc, the arc has smaller lateral oscillations, which gives a more stable welding arc and better welding seam quality. A control strategy was then developed based on the arc morphology to control the tungsten electrode height for real-time control of the tungsten electrode height during automatic welding.
朱志明, 程世佳, 于英飞, 符平坡. 焊接电弧形貌判别模型及钨极高度的影响规律[J]. 清华大学学报（自然科学版）, 2020, 60(4): 285-291.
ZHU Zhiming, CHENG Shijia, YU Yingfei, FU Pingpo. Automatic recognition and control of welding arc morphology as a function of the welding current and the tungsten electrode height. Journal of Tsinghua University(Science and Technology), 2020, 60(4): 285-291.
[1] 朱志明, 符平坡, 于英飞, 等. 基于图像的电弧波动行为表征及保护气体流量影响规律[J]. 焊接, 2018(10):1-4, 38. ZHU Z M, FU P P, YU Y F, et al. Characterization of arc fluctuation behavior based on image and effects of shielding gas flow rate[J]. Welding & Joining, 2018(10):1-4, 38. (in Chinese) [2] 朱志明, 程世佳, 符平坡, 等. 焊接电弧行为特征和稳定性评价研究与进展[J]. 焊接, 2018(11):1-6, 10. ZHU Z M, CHENG S J, FU P P, et al. Research and progress on behavior characteristics and stability evaluation of welding arc[J]. Welding & Joining, 2018(11):1-6, 10. (in Chinese) [3] 杨德宇. 液下等离子体电弧形态分析与稳定性研究[D]. 北京:北京化工大学, 2014. YANG D Y. Study on stability and speciation of submerged plasma arc[D]. Beijing:Beijing University of Chemical Technology, 2014. (in Chinese) [4] YANG M X, ZHENG H, QI B J, et al. Effect of arc behavior on Ti-6Al-4V welds during high frequency pulsed arc welding[J]. Journal of Materials Processing Technology, 2017, 243:9-15. [5] 冯东旭. 激光-TIG双面焊接电弧特性及组织性能研究[D]. 哈尔滨:哈尔滨工业大学, 2009. FENG D X. Study on arc characteristics and structure performance during laser-TIG double side welding[D]. Harbin:Harbin Institute of Technology, 2009. (in Chinese) [6] SHIGETA M, IKEDA T, TANAKA M, et al. Qualitative and quantitative analyses of arc characteristics in SMAW[J]. Welding in the World, 2016, 60(2):355-361. [7] 韩永全, 张世全, 庞世刚, 等. 铝合金变极性TIG焊接电弧行为[J]. 焊接学报, 2015, 36(9):51-54, 59. HAN Y Q, ZHANG S Q, PANG S G, et al. Arc behavior during variable polarity TIG welding of aluminum alloy[J]. Transactions of the China Welding Institution, 2015, 36(9):51-54, 59. (in Chinese) [8] 朱加雷, 焦向东, 乔溪, 等. 激光增强GMAW焊接熔滴过渡控制试验[J]. 焊接学报, 2014, 35(8):21-24, 29. ZHU J L, JIAO X D, QIAO X, et al. Experiment on metal transfer control of laser enhanced GMAW welding[J]. Transactions of the China Welding Institution, 2014, 35(8):21-24, 29. (in Chinese) [9] 王鹏, 李桓, 于福盛, 等. 铝合金三丝双脉冲MIG焊熔滴过渡及电信号分析[J]. 焊接学报, 2018, 39(10):98-102. WANG P, LI H, YU F S, et al. Analysis of droplet transfer and electrical signal in triple-wire double-pulse MIG welding of aluminum alloy[J]. Transactions of the China Welding Institution, 2018, 39(10):98-102. (in Chinese) [10] 陈树君, 张所来, 黄宁, 等. 电弧熔丝脉冲GTAW熔滴过渡行为分析[J]. 焊接学报, 2017, 38(1):17-21. CHEN S J, ZHANG S L, HUANG N, et al. Droplet transfer of arcing-wire pulse GTAW[J]. Transactions of the China Welding Institution, 2017, 38(1):17-21. (in Chinese) [11] XIAO X, HUA X M, LI F, et al. Spectroscopic measurement of temperature and gas composition in Ar-N2 shielded TIG welding[J]. Welding in the World, 2016, 60(6):1287-1296. [12] VILARINHO L O, SCOTTI A. Proposal for a modified fowler-milne method to determine the temperature profile in TIG welding at low currents[J]. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 2004, 26(1):34-39. [13] NOMURA K, KISHI T, SHIRAI K, et al. Temperature measurement of asymmetrical pulsed TIG arc plasma by multidirectional monochromatic imaging method[J]. Welding in the World, 2015, 59(2):283-293. [14] 郭波, 石永华, 易耀勇. 基于电弧形态的熔滴过渡形式识别[J]. 焊接学报, 2017, 38(11):27-31. GUO B, SHI Y H, YI Y Y. Metal transfer modes identification based on arc shape[J]. Transactions of the China Welding Institution, 2017, 38(11):27-31. (in Chinese) [15] 于英飞, 朱志明, 孙博文, 等. 焊接电弧图像的边缘检测及其批处理算法[J]. 焊接学报, 2018, 39(11):17-21. YU Y F, ZHU Z M, SUN B W, et al. Edges detection and batch algorithm for welding arc images[J]. Transactions of the China Welding Institution, 2018, 39(11):17-21. (in Chinese) [16] 张铮, 徐超, 任淑霞, 等. 数字图像处理与机器视觉——Visual C++与Matlab实现[M]. 2版. 北京:人民邮电出版社, 2014. ZHANG Z, XU C, REN S X, et al. Digital image processing and machine vision——Implementation of Visual C++ and Matlab[M]. 2nd ed. Beijing:Posts & Telecom Press, 2014. (in Chinese)
2020, Vol. 60 
