Measurement of Primary Dynamic Resistance of AC Resistance Spot Welding Using Power Factor and Piecewise Spline Interpolation

2011 ◽  
Vol 4 (6) ◽  
pp. 1939-1944 ◽  
Author(s):  
Xianfeng Wang ◽  
Guoxiang Meng ◽  
Yongbing Li ◽  
Wenhua Xie ◽  
Zhengjin Feng
Keyword(s):  
Power Factor ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Spline Interpolation ◽  
Dynamic Resistance ◽  
Resistance Spot

A new measurement method for the dynamic resistance signal during the resistance spot welding process

2016 ◽  
Vol 27 (9) ◽  
pp. 095009 ◽  
Author(s):  
Lijing Wang ◽  
Yanyan Hou ◽  
Hongjie Zhang ◽  
Jian Zhao ◽  
Tao Xi ◽  
...  
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Measurement Method ◽  
Welding Process ◽  
Dynamic Resistance ◽  
Resistance Spot

Modeling Dynamic Electrical Resistance During Resistance Spot Welding

2000 ◽  
Vol 123 (3) ◽  
pp. 576-585 ◽  
Author(s):  
S. C. Wang ◽  
P. S. Wei
Keyword(s):  
Electrical Resistance ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Transport Processes ◽  
Dynamic Resistance ◽  
Resistance Curve ◽  
Bulk Resistance ◽  
Resistance Spot ◽  
Faying Surface ◽  
Stage 4

Dynamic electrical resistance during resistance spot welding has been quantitatively modeled and analyzed in this work. A determination of dynamic resistance is necessary for predicting the transport processes and monitoring the weld quality during resistance spot welding. In this study, dynamic resistance is obtained by taking the sum of temperature-dependent bulk resistance of the workpieces and contact resistances at the faying surface and electrode-workpiece interface within an effective area corresponding to the electrode tip where welding current primarily flows. A contact resistance is composed of constriction and film resistances, which are functions of hardness, temperature, electrode force, and surface conditions. The temperature is determined from the previous study in predicting unsteady, axisymmetric mass, momentum, heat, species transport, and magnetic field intensity with a mushy-zone phase change in workpieces, and temperature and magnetic fields in the electrodes of different geometries. The predicted nugget thickness and dynamic resistance versus time show quite good agreement with available experimental data. Excluding expulsion, the dynamic resistance curve can be divided into four stages. A rapid decrease of dynamic resistance in stage 1 is attributed to decreases in contact resistances at the faying surface and electrode-workpiece interface. In stage 2, the increase in dynamic resistance results from the primary increase of bulk resistance in the workpieces and an increase of the sum of contact resistances at the faying surface and electrode-workpiece interface. Dynamic resistance in stage 3 decreases, because increasing rate of bulk resistance in the workpieces and contact resistances decrease. In stage 4 the decrease of dynamic resistance is mainly due to the formation of the molten nugget at the faying surface. The molten nugget is found to occur in stage 4 rather than stage 2 or 3 as qualitatively proposed in the literature. The effects of different parameters on the dynamic resistance curve are also presented.

scholarly journals Effect of Zinc Coating on Delay Nugget Formation in Dissimilar DP600 - AISI304 Welded Joints Obtained by the Resistance Spot Welding Process

2021 ◽  
Author(s):  
Mercedes Pérez de la Parte ◽  
Alejandro Espinel Hernández ◽  
Mario César Sánchez Orozco ◽  
Angel Sánchez Roca ◽  
Emilio Jiménez Macias ◽  
...  
Keyword(s):  
Welded Joints ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Zinc Coating ◽  
Welding Process ◽  
Dynamic Resistance ◽  
Time Duration ◽  
Resistance Spot ◽  
Nugget Formation ◽  
Resistance Curves

Abstract This paper researches the effect of zinc coating of galvanized DP600 steel on the dynamic resistance and the delayed nugget formation of dissimilar DP600 - AISI304 welded joints, obtained with resistance spot welding process (RSW). The RSW evaluations consisted of determining, from the dynamic resistance curves, the time involved in the different stages of the process, particularly the beginning of nugget formation. The experimental results showed that, from the dynamic resistance curves, it is possible to identify 8 distinct stages during the welding of galvanized DP600 steel and AISI304 stainless steel. In the case of the welding of uncoated DP600 steel with AISI304, only 6 stages are identified (except for stages 2 and 3), which are directly related to the heating, softening and melting of the galvanic coating. The energy used in stages 2 and 3, causes a delay in the beginning of nugget formation for welded joints obtained with galvanized DP600 steel compared to uncoated DP600 - AISI304 welded joints, reaching values between 37.28 ms and 52.29 ms for the welding conditions analyzed. Monitoring the time duration of stages 2 and 3, as defined from the analysis of the dynamic resistance curves, could be used as a tool to predict the beginning of nugget formation in the welding of galvanized steels, to avoid undesirable phenomena such as expulsion and to guarantee the quality of the welded joints.

scholarly journals Modified Recurrence Plot for Robust Condition Monitoring of Electrode Tips in a Resistance Spot Welding System

2020 ◽  
Vol 10 (17) ◽  
pp. 5860
Author(s):  
Wonho Jung ◽  
Hyunseok Oh ◽  
Dong Ho Yun ◽  
Young Gon Kim ◽  
Jong Pil Youn ◽  
...  
Keyword(s):  
Condition Monitoring ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Recurrence Plot ◽  
External Noise ◽  
Dynamic Resistance ◽  
Resistance Spot ◽  
Welding Electrode ◽  
Welding System

Degraded electrodes in a resistance spot welding system should be replaced to ensure that weld quality is maintained. Welding electrodes are subjected to different environmental and operational loading conditions during use. When they are replaced with a fixed interval, replacement may occur too early (raising maintenance costs) or too late (leading to quality issues). This motivates condition monitoring strategies for resistance spot welding electrode tips. Thus, this paper proposes a modified recurrence plot (RP) for robust condition monitoring of welding electrode tips in resistance spot welding systems. The overall procedure for the proposed condition monitoring approach consists of three steps: (1) transformation of a one-dimensional signal to a two-dimensional image, (2) unsupervised feature extraction with LeNet architecture-based convolutional neural networks, and (3) health indicator calculation. RP methods convert dynamic resistance waveforms to RPs. The original RP method provides an image with binary-colored pixels (i.e., black or white) that makes this method insensitive to the change of the waveform signal. The proposed RP method is devised to be sensitive to the change of the waveform signal, while enhancing robustness to external noise. The performance of the proposed RP method is evaluated by examining simulated aperiodic waveform signals with and without external noise. A case study is presented to examine the proposed method’s ability to monitor the condition of resistance spot welding electrodes. The results show that the proposed method outperforms handcrafted, feature-based condition monitoring methods. This study can be used to accurately determine the lifetime of welding electrodes in real time during the spot welding process.

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