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.

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

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 Adaptive Control of Resistance Spot Welding Based on a Dynamic Resistance Model

2019 ◽  
Vol 24 (4) ◽  
pp. 86 ◽  
Author(s):  
Kas ◽  
Das
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Controller Design ◽  
Welding Process ◽  
Dynamic Resistance ◽  
Resistance Spot ◽  
Control Scheme ◽  
Metal Sheets ◽  
One Step ◽  
Welding Processes

Resistance spot welding is a process commonly used for joining a stack of two or three metal sheets at desired spots. Such welds are accomplished by holding the metallic workpieces together by applying pressure through the tips of a pair of electrodes and then passing a strong electric current for a short duration. This kind of welding process often suffers from two common drawbacks, namely, inconsistent weld quality and inadequate nugget size. In order to address these problems, a new theoretical approach of controlling resistance spot welding processes is proposed in this paper. The proposed controller is based on a simplified dynamical model of the resistance spot welding process and employs the principle of adaptive one-step-ahead control. It is essentially an adaptive tracking controller that estimates the unknown process parameters and adjusts the welding voltage continuously to make sure that the nugget resistance tracks a desired reference resistance profile. The modeling and controller design methodologies are discussed in detail. Also, the results of a simulation study to evaluate the performance of the proposed controller are presented. The proposed control scheme is expected to reduce energy consumption and produce consistent welds.

scholarly journals Analysis of the Behavior of Dynamic Resistance, Electrical Energy and Force between the Electrodes in Resistance Spot Welding Using Additive Manufacturing

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 690
Author(s):  
Márcio Batista ◽  
Valdir Furlanetto ◽  
Sérgio Duarte Brandi
Keyword(s):  
Thermal Expansion ◽  
Additive Manufacturing ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Electrical Energy ◽  
Dynamic Resistance ◽  
Low Carbon ◽  
Resistance Spot ◽  
Welding Spot

This work is aimed at the analysis of the dynamic resistance, electrical energy and behavior of the force between electrodes (including thermal expansion) during welding at optimized parameters, referring to the process of spot welding using additive manufacturing (AMSW). For comparative purposes, this analysis also includes the conventional resistance spot welding process (RSW). The experiments were done on low carbon-zinc-coated sheets used in the automotive industry. The results regarding the welding process using additive manufacturing (AMSW), in comparison to the conventional resistance spot welding (RSW), showed that the dynamic resistance presented a different behavior due to the collapse of the deposition at the beginning of the welding, and that a smaller magnitude of electrical energy (approximately <3.35 times) is required to produce a welding spot approved in accordance with the norm. No force of thermal expansion was observed during the passage of the current, in contrast, there was a decrease in the force between the electrodes due to the collapse of the deposition at the beginning of the welding.

scholarly journals Embedded Artificial Neuval Network-Based Real-Time Half-Wave Dynamic Resistance Estimation during the A.C. Resistance Spot Welding Process

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Liang Gong ◽  
Yan Xi ◽  
Chengliang Liu
Keyword(s):  
Real Time ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Measuring Method ◽  
Computing System ◽  
Dynamic Resistance ◽  
Resistance Spot ◽  
Half Wave ◽  
Artificial Neural Network Ann

Online monitoring of the instantaneous resistance variation during the A.C. resistance spot welding is of paramount importance for the weld quality control. On the basis of the welding transformer circuit model, a new method is proposed to measure the transformer primary-side signal for estimating the secondary-side resistance in each 1/4 cycle. The tailored computing system ensures that the measuring method possesses a real-time computational capacity with satisfying accuracy. Since the dynamic resistance cannot be represented via an explicit function with respect to measurable parameters from the primary side of the welding transformer, an offline trained embedded artificial neural network (ANN) successfully realizes the real-time implicit function calculation or estimation. A DSP-based resistance spot welding monitoring system is developed to perform ANN computation. Experimental results indicate that the proposed method is applicable for measuring the dynamic resistance in single-phase, half-wave controlled rectifier circuits.

Study of Dynamic Resistance Based Controllers for Resistance Spot Welding Process

2001 ◽  
Vol 34 (3) ◽  
pp. 32
Author(s):  
Madhubala T. Kadavarayar ◽  
K. Asok Kumar ◽  
S. Arumugam
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Dynamic Resistance ◽  
Resistance Spot
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