Eliminating short switching cycles when using hysteresis control of resistance spot welding systems

2017 ◽  
Vol 36 (3) ◽  
pp. 791-803 ◽  
Author(s):  
Jernej Černelič ◽  
Robert Brezovnik ◽  
Primož Sukič ◽  
Martin Petrun
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Control Algorithm ◽  
Welding Current ◽  
Control Algorithms ◽  
Iron Core ◽  
Content Type ◽  
Resistance Spot ◽  
Hysteresis Control ◽  
Current Ripple

Purpose This paper aims to present two hysteresis-control algorithms designed for medium-frequency, direct-current, resistance-spot-welding (MFDC RSW) systems. The first proposed control algorithm (MSCHC) eliminates the short switching cycles that can occur when using the existing hysteresis-control algorithms. This control minimises the number of switching cycles that are needed to generate the selected welding current. The welding-current ripple can be high when using this control algorithm. Therefore, a second algorithm (HCRR) is presented that reduces the welding-current ripple by half. Design/methodology/approach The proposed hysteresis controllers consist of the transformer’s magnetic-flux-density hysteresis regulator and a welding-current hysteresis regulator. Therefore, the welding current must be measured and the saturation of the iron core must be detected. The proposed hysteresis controller supplies the inverter with the signals needed to generate the supply voltage for the RSW transformer, which then generates the selected welding current. Findings The proposed MSCHC algorithm produces the smallest possible number of switching cycles needed to generate the selected welding current. The high welding-current ripple can be reduced if the number of switching cycles is increased. The observed number of switching cycles and the welding-current ripple change if the welding resistance and/or inductance change. Originality/value The number of switching cycles can be minimised when using the first proposed control algorithm (MSCHC), and so the switching power losses can be minimised. If the welding-current ripple produced by the first control algorithm is unacceptable, the second control algorithm (HCRR) can reduce it by increasing the number of switching cycles.

scholarly journals Optimization on Spot Weld Parameters in Resistance Spot Welding Process on AISI 304

2021 ◽  
Vol 11 (3) ◽  
pp. 181-185
Author(s):  
Amit Hazari ◽  
Rith Saha ◽  
Bidisha Ghosh ◽  
Debraj Sengupta ◽  
Sayan Sarkar ◽  
...  
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Welding Current ◽  
Electrical Current ◽  
Industrial Applications ◽  
Spot Weld ◽  
Welding Parameters ◽  
Resistance Spot ◽  
Weld Time

The spot welding procedure is used in a variety of industrial applications. The most critical elements influencing welding quality, productivity, and cost are the spot welding parameters. This research examines the effect of welding factors such as welding current and welding time on the strength of various welding joint designs. Resistance spot welding (RSW) is used in the automotive industry for manufacturing. This research focused on the optimization of process parameters for resistance spot welding (RSW), as well as the tensile testing and spot weld diameter. The goals of this analysis are to comprehend the physics of the process and to demonstrate the effect of electrical current, weld time, and material type on the resistance spot welding process.

Dynamic Electrode Force and Displacement in Resistance Spot Welding of Aluminum

2004 ◽  
Vol 126 (3) ◽  
pp. 605-610 ◽  
Author(s):  
C. T. Ji, ◽  
Y. Zhou,
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Current ◽  
Monitoring And Control ◽  
Resistance Spot ◽  
Nugget Diameter ◽  
Electrode Force ◽  
Rate Of Increase ◽  
Process Monitoring And Control ◽  
Electrode Displacement

Dynamic electrode displacement and force were characterized during resistance spot welding of aluminum alloy 5182 sheets using a medium-frequency direct-current welder. It was found that both electrode displacement and force increased rapidly at the beginning of the welding stage and then at a reducing rate. Rates of increase in electrode displacement and force were both proportional to welding current. And both electrode displacement and force experienced a sudden drop when weld metal expulsion occurred. However, the rate of increase in electrode displacement did not reach zero during welding even for joints with sufficient nugget diameter, while electrode force peaked when a large nugget diameter was produced. Possible strategies for process monitoring and control were also discussed.

A Comparative Study of AC and MFDC Resistance Spot Welding

2004 ◽  
Author(s):  
Wei Li ◽  
Daniel Cerjanec
Keyword(s):  
Comparative Study ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Welding Current ◽  
Median Frequency ◽  
Resistance Spot ◽  
Secondary Voltage ◽  
Nugget Growth ◽  
Welding Processes

This paper presents a comparative study of the AC and MFDC resistance spot welding process. Two identical welders were used; one with a single phase AC and the other with a median frequency DC weld control. Both welders were instrumented such that the primary and secondary voltage and current could be collected. A nugget growth experiment was conducted to compare the weld size and energy consumption in the AC and MFDC welding processes. It is found that the MFDC process generally produces larger welds with the same welding current. However, this difference is more prominent when the welding current is low. Overall the AC welding process consumes more energy to make a same size weld. The larger the welding current is used, the less efficient the AC process becomes.

Dissimilar resistance spot welding of AISI 304 to AISI 409 stainless steels: mechanical properties and microstructural evolutions

2018 ◽  
Vol 115 (6) ◽  
pp. 610 ◽  
Author(s):  
Mehdi Safari ◽  
Hossein Mostaan ◽  
Abdoreza Ghaderi
Keyword(s):  
Stainless Steels ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Steel Sheet ◽  
Welding Current ◽  
Stainless Steel Sheet ◽  
Tensile Shear ◽  
Aisi 304 ◽  
Resistance Spot ◽  
Electrode Force

In this work, dissimilar resistance spot welding of austenitic stainless steel sheet (304 grade) and ferritic stainless steel sheet (409 grade) is studied experimentally. For this purpose, the effects of process parameters such as welding current, welding time and electrode force on tensile-shear strength of resistance spot welded joints are investigated with response surface methodology (RSM). Also, microstructural evolutions during resistance spot welding process of AISI 409 and AISI 304 stainless steels are evaluated by optical microscopy. It is concluded from results that the tensile-shear strength of spot welds is increased with increasing the welding current, welding time and electrode force. It is shown that widmanstatten ferrites have been grown in the weld metal of dissimilar resistance spot welds of AISI 304 and AISI 409 stainless steels.

Experimental Investigation on Solid State Resistance Spot Welding

2017 ◽  
Author(s):  
Zhijun Wu ◽  
Guanlin Zhang ◽  
Bingxu Wang ◽  
Kelvin Shih
Keyword(s):  
Solid State ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Mechanical Performance ◽  
Thin Sheet ◽  
Welding Current ◽  
Sheet Metals ◽  
Resistance Spot ◽  
Nugget Formation ◽  
State Resistance

Resistance Spot Welding (RSW) is one of the most common and dominant technologies utilized in the automotive industry to join the thin sheet metals together, and expulsion is a common phenomenon during the operation. How to ensure the high quality nugget formation and joining performance is essential to ensure the quality and integrity of structures. In this study, solid state resistance spot welding is introduced in order to prevent expulsion. The effect of welding current and welding time on the mechanical performance of the solid state RSW in terms of nugget size, tensile performance and nugget formation will be investigated experimentally by using steel sheet metals. Microstructure and micro-hardness of the nugget cross-section will be evaluated as well.

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