Resistance Spot Welding Machine Research Articles

RANCANG BANGUN PROTOTIPE PREPARASI MATERIAL RESISTANCE SPOT WELDING

The manufacturing process in the automotive industry is in dire need of resistance spot welding machines. Because it was easier to use, highly effective, and effective in functioning. However, there were sometimes still connection problems that were still of poor quality, both nuggets and areas that are subject to electrode pressure. To get a quality welding connection, a machine was needed that was able to carry out good material preparation in the form of sanding, able to set the welding current analogously, able to set the time with an automatic timer, able to apply pressure on the electrode measurably during the welding process. The research aimed to design a prototype of resistance spot welding material preparation that could adequately carry out material preparation and welding using a Bluetooth system connected to a mobile phone. The research methods carried out were as follows: first, designing the machine using Autodesk Inventor software, then the device was made with a focus on material preparation prototypes, then the machine elements were made for the material clamping rail, then the machine elements in the control section using Bluetooth connected to the mobile phone, the machine was tested, then the connection quality testing process was carried out on the tensile testing machine. The results showed that the design results had been made using elbows and iron plates with threaded rails with a length of 650 mm, which became material clamping rail grooves with a drive using window motors controlled by Bluetooth on the Arduino circuit. The test results of welded joints show that the roughness is 0.20 μm which has the highest tensile strength.

Quality Analysis of Welds Made with an Automatic Battery Pack Spot Welding Machine

This paper presents quality testing of battery pack welds for different welding time parameters of an automatic resistance spot welding machine. Several quality testing methods commonly used in studies of welded joints were described. Finally, the breakage test destructive method was chosen and used in this research. To investigate the influence of welder parameters on the quality of the welded joints, the programmable resistance spot welding machine was designed and constructed. As the studied samples, the 18650 cell type and the 8 mm × 0,15 mm cell packaging nickel plated steel tape were chosen as the most commonly used for the construction of battery packs for personal electric vehicles. The impact of each time constants set on the spot welding process was measured by the self-designed and constructed strength testing machine. After a series of tests with different parameters of spot welding process, the final conclusions were formulated.

Effect of Al-Si coating weights on weldability of hot-stamped ultra-high-strength steel (UsiborR 1500) used in automotive structures

ABSTRACT Automotive industries have seen increased demands for indirect hot-stamped pre-coated ultra-high-strength steel 22MnB5 due to its excellence. This paper presents the results of experimental investigation of the effect of Al-Si coating weights AS150 (150 g/m2) and AS80(80 g/m2) and spot-welding process parameters of indirect hot-stamped Usibor 1500 to further understand which coating weight perform better for automotive application. The resistance spot welding experiments were conducted with a medium-frequency direct control (MFDC) machine. The MFDC resistance spot-welding machine had two G20 electrodes with a 458 truncated cone designed with a diameter of 4.9 mm. The results show that the nugget diameter increases with increasing weld current, better spot-weld nugget diameter is recorded at weld currents above 7.5 kA for both AS80 and AS150 coating weights, and the weld current range decreases with increase in coating weight and with increase in the interdiffusion layer. Heat treatment dwell time has a remarkable influence on weld current range for both AS150 and AS80 coating weights. AS80 coating weight has a slightly higher weld current range of 2.1 KA than AS150 coating weight with weld current range of 1.8 KA. Tensile shear strength for AS150 and AS80 increases nonlinearly with increase in weld diameter.

Intelligent parameters measurement of electrical structure of medium frequency DC resistance spot welding system

Three phase medium frequency direct current (DC) resistance spot welding (RSW) machine has a complex electrical structure. Because the structure included various electrical components, it is hard to establish an accurate and integrated numerical model to simulate the energy delivery and control process. This study employed a particle swarm optimization (PSO) algorithm to conduct an intelligent parameters measurement. The measurement process included three procedures, based on electrical and physical characteristics of the objective electrical system. To verify the accuracy and reliability of the measurement, another numerical model established by MATLAB Simulink was employed. The comparative results showed that the maximum error of all measured parameters was 1%, which meant that the proposed intelligent parameter measurement method was effective, and convinced measurement results can be obtained. This study can benefit to establish a full process numerical calculation or evaluation model of the medium frequency DC RSW system.

Multi Response Optimization of Spot Welding Process Parameters by Taguchi Method

Electrode deterioration by deformation and chemical reaction during resistance spot welding of steel sheets confirming to AISI1020 is an issue for class II electrode. In view of this, the present study carried out the impacts of squeeze, weld, current and pressure on the nugget diameter, height, force and waviness of welding joint in electrical resistance spot welding of 0.8mm and 1.5 mm thickness of steel sheets with class II electrode to achieve the benefits of cost saving and quality products. A timer and current controlled electrical resistance spot welding machine having 120 kVA capacities were used. During welding process, current periods of 5, 10, 15, 20 and 25 were selected and it was adjusted by increasing from 8 to 10 kA. The optimum welding parameter for multi objectives was obtained using multi signal to noise ratio and the significant level of the welding parameters was further analysed by analysis of variance for all responses. Based on the confirmation test results, it is found out that the developed model can be effectively used to predict the size of weld zone which can improve the welding quality and performance in GRA. The details of welded joint generated by class II electrode were measured and results were analysed in detail.

Numerical simulation of weld nugget in resistance spot welding process

The resistance spot welding (RSW) stands different over other welding techniques as the actual weld nugget is shaped internally relative to the surface of the base metal. The weld formed is fundamentally a mix of heat, pressure and time. The welding conditions are precisely controlled to produce sound nuggets. The application of interface pressure allows accurate prediction of interfacial heat and electrical resistance, which plays a dominant role in Joule’s heat generation. In this work, lap welding using resistance spot welding has been numerically investigated for Mild steel (G-3302) and Stainless steel (SS-202) sheets. Spot welding has been completed by utilizing a 35 kVA DC type resistance spot welding machine, constrained by a Programmable Logic Controller unit. For both materials, two spots, three spots and four spots weld were done in order to obtain various comparative results. The weld nugget formation has been simulated using SIMULIA. The 3D model has been created by using GUI of commercial FEA package ABAQUS 6.14. The model employs coupled thermal-electrical-mechanical analysis. Simulation has been performed for pertinent parameters in ABAQUS 6.14. The obtained plots from numerical model are found to be in strong consistency with experimental data.

Effect of Silicon and Retained Austenite on the Liquid Metal Embrittlement Cracking Behavior of GEN3 and High-Strength Automotive Steels

GEN3 steels are a new family of automotive sheet steels developed and commercialized in the last three years, specifically for body-in-white applications. The high ductility in GEN3 steels is typically achieved through the transformation-induced plasticity (TRIP) effect by the addition of silicon or aluminum. When these steels are formed into parts, the TRIP effect of austenite to martensite transformation provides enhanced ductility. Typically, 10 to 12 micrometers of zinc coating (known as galvanized coating) is applied to automotive steel sheets for corrosion protection. Liquid metal embrittlement (LME) cracking can occur during resistance spot welding (RSW) of galvanized steels. LME cracking occurs when molten zinc penetrates prior austenite grain boundaries of the steel substrate. The precise role of silicon in the LME cracking behavior in TRIP and GEN3 steels is unknown. Therefore, a study was undertaken to examine the role of silicon in LME cracking behavior of GEN3 steels. The purpose was also to examine if the presence of retained austenite is required for LME cracking to occur. In this study, laboratory heats were prepared using three silicon levels. Samples cut from galvanized panels were welded using a resistance spot welding machine, and weld areas were examined metallographically for the presence of LME cracks. Gleeble® simulations were done to study the LME behavior of the three steels prepared. Base materials were examined with a scanning electron microscope using the electron back-scattered diffraction (EBSD) method to examine the nature of grain boundaries found. The effect of retained austenite in LME cracking was studied using the Gleeble®. Both RSW and Gleeble® results showed silicon promotes LME cracking in steels, predominantly in the weld heat-affected zones(HAZs). More low-energy, low-coincidence site lattice (CSL) boundaries were found as the silicon content of the steel was decreased. These boundaries do not host cracks. Higher silicon appeared to shrink the safe temperature range over which LME cracks could be avoided, thus indicating heat in-put control to limit cracks has limited windows as the silicon in steel goes up. It was shown that the presence of retained austenite in steel is not a prerequisite for LME cracking to occur.

Empirical Modelling of a Prototype Resistance Spot Welding Machine

Resistance spot welding (RSW) has been extensively used in the automotive and aerospace industries over the years. The weld quality of spot welds is affected by the welding parameters like electrode force, weld time, electrode current and workpiece size/shape parameters like workpiece thickness. This study focuses on the effect of electrode force, weld time and workpiece thickness on the weld quality of mild steel samples where the aim is to correlate the weld strength to welding parameters of a portable RSW machine installed at the Nigerian Liquefied Natural Gas (NLNG) laboratory of the Department of Mechanical Engineering, University of Nigeria, Nsukka. Lap shear weld samples are tested for strength, and the results are used to develop an empirical model. The developed model has a coefficient of determination of 0.6365 and a correlation coefficient of 0.7978. Hypothesis testing at 5% significance level discovered that the most significant predictor is the cross interaction of the workpiece thickness and electrode force with p-value of 0.02367 and that the model is significant with a p-value = 0.0453. The model is validated by further welding operations and tensile shear tests which gave a percentage error not exceeding 12.92% but was as low as 6.35%.

Optimization of Spot Welding Parameters in Similar and Dissimilar Alloys AISI-321 and Inconel-X750 Alloys

A series of experiments were conducted to optimize the welding of similar and dissimilar alloys i.e AISI-321 with AISI-321, Inconel-X750 with AISI-321 and Inconel-X750 with Inconel-X750. Single phase rectification type resistance spot welding machine was utilized for this purpose. Breaking load against different welding parameters was observed. Further, the defects of the welded zone were also studied by optical and stereo microscopes. It was noted that the welding current, welding time and the welding force play an effective role in the strength of the welding joint and the spot welding of Inconel-X750 with AISI-321 can be possible if the welding parameters are carefully selected.

Dobór urządzeń do zgrzewania oporowego punktowego z wykorzystaniem analizy skupień

The paper presents the issue of selection of the resistance spot-welding machines, stating that there is no objective method of supporting the decision to purchase such devices. The application of cluster analysis method has been suggested for solving the problem. Diagnostic data describing 35 resistance spot-welding machines have been collected and then their classification has been made by the Ward and k-means methods. Based on the results, it has been concluded, that the cluster analysis can be an effective preliminary method of supporting the decision of purchasing resistance spot-welding machines.

Optimizing the resistance spot-welding process for dissimilar stainless steels

The objective of this study was to identify the ideal welding circumstances to conduct resistance spot-welding in the case of 316 austenite and 425 ferrite stainless steels, which offer the challenge of being dissimilar. The study examines a number of welding variables, including weld current, weld time, hold time, electrode force, and the upper and lower electrode types. Initially, a 26-1 fractional factorial design was used for the screening of variables involved in the process. After this stage, the Box-Behnken design was employed for analysis of those variables and in order to specify the multiple response optimizations applicable to the size of nuggets through examination of the desirability function. The experiment was run using a resistance spot-welding machine at 50 kVA, 50 Hz. The quality of welded specimens was determined by their penetration, nugget diameter and nugget area. The optimal welding conditions were found to be 3.3 kN of electrode force, 25 cycles of weld time, 10,000 amperes of weld current, 50 cycles of hold time, and both R30 types of up-low electrodes. The optimal welding conditions provided nugget sizes of quality which were able to pass the specifications of the customer.

EFFECT OF FATIGUE TEST ON SPOT WELDED STRUCTURAL JOINT

Spot welding is mainly used method in joining sheet metals for body structure in automotive industry. The comprehension of the fatigue strength for the spot welds is very critical in automotive component design. Parameter for the resistance spot welding and fatigue machines is constant for each specimen used. The S-N curve is obtained from the fatigue testing for each specimen. This experiment parameters are varies the different thickness and different material combination in spot welding structure to investigate the fatigue life cycle and fatigue stress. For 1050A aluminium joint, fatigue life cycle and fatigue strength will decrease from number of cycle 500 at 16.58 MPa to number of cycle 61 at 6.62 MPa as the thickness increase. The fatigue life cycle and fatigue stress for galvanized iron will increase from number of cycle  46 at 9.25 MPa to number of cycle 1500 at 57.8 MPa when the thickness of joint increase. The finding from the combination of 1050A aluminum and galvanized iron on spot welded structure has shown no improvement in term of fatigue life cycle and fatigue strength because specimens experienced failure at number of cycle 19 with fatigue stress 2.36 MPa.

Стабилизация сварочного тока контактных точечных машин при колебаниях напряжения питающей сети

Стабилизация сварочного тока контактных точечных машин при колебаниях напряжения питающей сети

Stabilization of welding current of resistance spot welding machines at mains voltage fluctuations

Stabilization of welding current of resistance spot welding machines at mains voltage fluctuations

Review of Application of the Electrical Structure in Resistance Spot Welding

Resistance spot welding (RSW) is frequently employed in current industrial occasions. This paper reviewed recent advances of the electrical structure of the RSW system. Two types of electrical structures are used in RSW machines. Single-phase ac power source has a simple structure but low control frequency and power factor, and the measurement and control for the machine have some special operations. While three-phase medium frequency dc power source has a complex structure and high control frequency but high cost, and frequently switching the direction of the output welding current may induce many negative phenomena in the welding transformer. The characteristics of the two structures are presented in detail in this paper. Corresponding measures have been taken to deal with the phenomena during the process, respectively, for the two types of electrical structures, according to the previous works. Though many significant achievements have been gained in previous works, it is expected to be more improvements required in the future. This paper can provide references and enlightens for academic researches or actual production in RSW operations.

The Effect of Nugget Sizes on Mechanical Properties in Resistance Spot Welding of S235JR(Cu) Steel Sheets Used in Railway Vehicles

This paper presents an experimental study on the resistance spot welding of S235JR(Cu) steel sheets used in side walls and roofs of rail vehicle bodies. A timer and current controlled resistance spot welding machine having 120 kVA capacity and a pneumatic application mechanism with a single lever were used to prepare the specimens. Welding duration was chosen to be 5, 10, 15, 20, 25 and 30 periods (1 period = 0.02 s) and also welding currents were increased from 6 kA up to 14 kA in steps of 0.5 kA. The electrode force was kept constant at 6 kN. The obtained welding joints were exposed to tensile peel and tensile shear tests and their nugget sizes were measured by means of an optical microscope. The effect of nugget sizes on tensile peel strength and tensile-shear strength was determined using weld lobe diagrams. Based on this data the optimum welding currents and times were advised.

The Effect of Welding Current on Nugget Sizes in Resistance Spot Welding of SPA-C Steel Sheets Used in Railway Vehicles

This paper presents an experimental study on resistance spot welding of SPA-C steel sheets used in side wall and roof in rail vehicles. SPA-C steel sheets having 2.3 mm thicknesses were joined by using resistance spot welding as lap joint. A timer and current controlled resistance spot welding machine having 120 kVA capacity and a pneumatic application mechanism with a single lever was used to prepare the specimens. Welding periods were chosen as 10, 15, 20, 25 and 30 periods and also welding currents were increased from 6 kA up to 11.5 kA by rise of 0.5 kA. The electrode force was kept constant at 6 kN. The nugget sizes of prepared welding specimens were calculated by means of an optical microscope and the obtained results were supported by diagrams and, finally, appropriate welding parameters were advised to the users.

New technology for measuring resistance of electrical contact and estimating welding quality

Incomplete penetration is a common defect in the welding gap of large size (welding area is over 100 mm2) electrical contact, which leads to an instability of welding quality. Nevertheless, there was limited research dealing with non-destructive quality inspection of electrical contact. In this research, the resistance of CJ400 electrical contact was measured with the device medium frequency inverter resistance spot welding (MFI-RSW) machine. Multipulse measuring method was designed and proved efficient to reach a higher accuracy by restraining the influence of the contact resistance between electrodes and electrical contact. Moreover, the error of resistance caused by temperature rising in the measuring process is also eliminated effectively. Therefore, more accurate resistance of electrical contact could be extracted compared to the method of single pulse measuring. Then, the relationship between resistance and welding quality was studied and a new quality inspection method was proposed.

Welding Time Effect on Mechanical Properties in Resistance Spot Welding of S235JR(Cu) Steel Sheets Used in Railway Vehicles

This paper presents an experimental study on resistance spot welding of SPA-C steel sheets used in rail vehicles. SPA-C steel sheets having 2.3 mm thicknesses were joined by using resistance spot welding as lap joint. A timer and current controlled resistance spot welding machine having 120 kVA capacity and a pneumatic application mechanism with a single lever was used to prepare the specimens. Welding periods were chosen as 5, 10, 15, 20, 25 and 30 cycles and also welding currents were increased from 6 kA up to 14 kA by rise of 0,5 kA. The electrode force was kept constant at 6 kN. The obtained welding joints were exposed to tensile-peel and tensile-shear tests. Welding time effect on tensile-peel strength and tensile-shear strength were researched by using related diagrams and the optimum welding currents and times were advised.

용융아연도금 강판 저항 점 용접 시 정전류 및 적응제어 적용에 따른 연속타점 특성 평가 및 고찰

With using adaptive control of the resistance spot welding machine, the advantage on electrode life time for galvanized steels has been addressed. This study was aimed to evaluate the electrode life time of galvanized steels with applying the constant current control and the adaptive control resistance spot welding process for a comparison purpose. The growth in diameter of electrode face was similar for both the constant current and the adaptive control up to 2000 welds. The button diameter was decreased with weld numbers, however, sudden increase in button diameter with use of the adaptive control after 1500 welds was observed. The peak load was continuously decreased with increasing number of welds for both the constant current and the adaptive control. The current compensation during a weld was observed with using the adaptive control after 1800 welds since the -peak on dynamic resistance curve was detected at later weld time. The current compensation with adaptive control during resistance spot welding enhanced the nugget diameter at the faying interface of steel sheets and improved the penetration to thinner steel sheet.