Resistance Welding Research Articles

Flexible Encapsulation and Module of Thin‐Film GaInP/GaAs/InGaAs Solar Cells

Lightweight and flexible III–V solar cells create new opportunities for application in satellites, drones, and wearable devices. In this article, a module manufacturing scheme based on resistance welding and lamination technology is proposed to meet the demands of practical application. A combined laminate structure of ethylene–tetrafluoroethylene plus ethylene octene copolymer and polyimide is used to encapsulate flexible III–V solar cells. In laboratory measurements with a spectrum close to AM1.5G, the photoelectric conversion efficiency of the flexible solar cell is 34.4% with an open‐circuit voltage of 3.04 V, and the efficiency of the flexible module is 32.7% with a weight density of 469 g m−2. The electroluminescence measurements show good performance of the flexible solar cell module, which is expected to achieve large‐size flexible III–V solar cells encapsulation.

A decision support tool for intelligent manufacturing systems via an elevator kinematic optimisation based method

This paper presents a novel centralised method to solve the manufacturing parameter design problem based on evolutionary computation elements using a novel elevator kinematic optimisation algorithm. The new method is referred to as compromise multi response surface optimisation method. Its evolutionary computation nature simultaneously produces several flexi-design plans to prevent a high number of experiments and is used within the design phase of Taguchi arrays. The new method also provides various channels via available information for choosing the parameter levels during the analysis phase without new individual fitting sets. The industrial application used for benchmarking the new approach revealed that the proposed design and analysis method could lead to better optimal solutions for complex processes such as resistance welding than those of a conventional Taguchi method.

Influence of the Process Input Parameters on the Cross-Wire Weld Breaking Force

Cross-wire welding is a type of electric resistance welding called projection welding that is used in the production of a variety of products. This paper deals with the case where steel wires of equal radii are joined together to form a reinforced steel mesh. The objective of the study is to determine the correlation between the welding parameters and the breaking force of the weld. Each weld is cut out from the given wire mesh and tested separately by destructive testing on the universal testing machine. A modular testing fixture was constructed for the tests. Although the tests are still in the initial stage, the results already give a good insight into the influence of the process input parameters on the breaking strength of the weld.

Analysis of the Cross-Wire Welding Process Stability

The research paper was prepared within the framework of a project whose aim is to improve the durability of the corrosion protection properties of the product by regulating the input parameters of the cross-wire welding process. Cross-wire welding is a subtype of electric resistance welding. Products made by the cross-wire welding process are widely used in everyday life and can be found in the form of grids, gratings, fencing systems, baskets, guards, etc. The subject of the research work is a preliminary analysis of the stability of the cross-wire welding process. The results of the performed analysis will serve as a starting point for the second phase of the project. Since the recorded values of the set down output parameter differ significantly from the expected values, this parameter is considered as an indicator of the process stability. From the specific trend of the results in the performed analysis, it was concluded that the position of the electrode has a significant influence on the result, which was confirmed by comparing the test results before and after the preliminary tests.

State-of-the-Art Technologies in Piezoelectric Deformable Mirror Design

In this work, two advanced technologies were applied for manufacturing a bimorph wavefront corrector: laser ablation, to vaporize conductive silver coating from piezoceramic surface, and parallel-gap resistance microwelding, to provide a reliable electrical contact between the piezodisk surface silver electrodes and copper wires. A step-by-step guide for bimorph mirror production is presented, together with the ‘bottlenecks’. Optimization of the laser ablation technique was carried out using an Nd:YAG laser with an output power of 4 W and a frequency of 20 kHz. A comparison of the ultrasonic welding and parallel-gap resistance microwelding methods was performed. The tensile strength in the first case was in the range of 0.2…0.25 N for the system ‘copper wire–silver coating’. The use of resistance welding made it possible to increase the value of this parameter for the same contact pair by almost two times (0.45…0.5 N).

Effects of Electro-force Control on the Microstructure and Welding Characteristic During Resistance Spot Welding

Recently, lightweight vehicle bodies are in increasing demand to satisfy exhaust gas and environmental regulations around the world. In particular, aluminum alloys are widely used to manufacture lightweight parts, because of their excellent properties including corrosion resistance and mechanical properties. After the forming process, the welding process is important for manufacturing aluminum alloy parts. Resistance welding of aluminum alloys has several problems, due to internal weld defects such as cracks, shrinkage cavity, or porosity, which can result from the Al2O3 oxide film on the surface of the aluminum alloy. This study investigated electrode-force type controls to improve the weldability of the aluminum alloy. It was found that a high electrode-force on squeeze time can collapse the Al2O3 oxide film on the surface. It can reduce defects in the nugget by about 42%, by reducing heat input energy, compared to the continuous electrode-force 4 kN (reference value). Also, with high electrode-force during the hold time, defects were reduced by about 80%, by increasing the cooling rate. The weld quality has a great influence on the electrode-force type control, and internal defects in the nugget are greatly affected by the electrode-force on hold time.

An additional hole to compensate for mechanical property of thermoset composite and aluminum alloy joint during resistance welding

A hole in the center of the aluminum (Al) alloy was processed to compensate for the mechanical properties of resistance welded joints of the carbon fiber reinforced epoxy resin matrix (CF/Epoxy) laminate and Al alloy for solving the problem of poor bonding quality in the center of the joint due to uneven temperature distribution in the resistance welding process. The resistance welded lap configuration of the upper Al and the lower laminate was employed, and through holes with a different diameter (d h) were prefabricated on the upper Al alloy plates. The molten polyetherimide (PEI) resin was bonded to the surfaces of the samples on both sides under the action of Joule heat, and the excess PEI resin filled the prefabricated through-hole of the Al alloy plate under pressure and realized the jointing of the 6063Al alloy plate and the CF/Epoxy laminate. The micro-morphology of the welded interface was characterized by scanning electron microscopy (SEM), and the heat distribution of the sample was simulated using COMSOL. The tensile shear force of the joint was tested, which rises with an increase of d h. The failure interface was analyzed in detail, which showed a strong correlation with d h.

Experimental study on magnetic flaw detection of micro-defects in ERW tubes

Chassis lightweight is one of the implementation of vehicle lightweight, the use of Electric Resistance Welding(ERW)welded pipe by bending and internal high pressure molding from the parts are an important part of the chassis components. Due to the limitation of welded pipe size, thin wall, high temperature and continuous production, the conventional nondestructive testing method is difficult to meet the continuous dynamic testing requirements of ERW welded pipe. In view of the small defect of ERW welded pipe, a method for detection of welded pipe defects based on the principle of electromagnetic induction is presented. Firstly, the fuzzy evaluation model of weld quality was established based on the fuzzy mathematics principle. Secondly, the welding mechanism of ERW was analyzed, and the microstructure of the weld was observed by metallographic microscope, and the microstructure of the weld was obtained. Finally, eddy current method, the low-frequency electromagnetic scanning method and magnetic induction method were used to detect ERW welded pipes. The data analysis shows that the magnetic induction method can realize dynamic detection and accurate localization of welded pipe defects, and the comprehensive detection effect is the best.

The Influence of Tuff Particles on the Properties of the Sintered Copper Matrix Composite for Application in Resistance Welding Electrodes

This paper presents modern copper-matrix composite materials in which volcanic tuff particles are used as a reinforcing phase. The aim of the research was to determine the optimal shares of volcanic tuff additive based on such criteria as softening temperature, relative density, electrical conductivity, and hardness. The properties of the produced and tested composites allowed us to determine the usefulness of this type of material for resistance welding electrodes. To confirm the assumptions made, preliminary investigations of the durability and behavior of electrodes made of the tested material during the processes of welding non-alloy steel sheets were carried out. As a result of the research, it was discovered that the addition of 5% tuff produces the best results in this type of composite. It was found that for the sample with a 5% share of tuff, a high softening point above 600 °C was obtained, high hardness after densification at the level of 62 HRB, and high relative density of approximately 95% and very good conductivity at the level of approximately 45 MS/m. The conducted tests did not show any electrode wear different from the commonly used alloys for resistance welding.

Upgrading the performance of functional Cu–Cr–Zr alloys for resistance welding electrodes

The gravity die casting method was used to produce functional Cu–Cr–Zr alloys with various compositions. The functional electrical, mechanical, and wear properties of Cu–Cr–Zr alloys were studied at different aging times at 500°C. The optimum aging time that results in the best combination of hardness and functional electrical properties changes with the chemical composition of the alloys; the alloys with higher Zr content require a longer time to attain peak hardness. Complicated wear mechanisms are active in the Cu–Cr–Zr alloys. The alloys with the highest Zr and Cr contents exhibit the highest hardness and tensile strength with low wear resistance. The best Cr content is found to be just below the solubility limit at the solutionizing temperature.

Trend of Resistance Spot Welding Technology of Al-Si Coated Hot-Stamped Boron Steel for Automobile Body

As environmental regulations have been tightened around the world, domestic and foreign automobile industries are increasing the proportion of hydrogen and electric automotive components using lightweight materials to reduce exhaust gas emissions and improve fuel efficiency. In particular, hot-stamped boron steel is being used as an alternative material for frame weight reduction due to thickness reduction, excellent workability, and good elongation. However, surface coating is essential to prevent surface decarburization phenomena and oxidation scale formation between hot stamping processes of boron steel. The coating layer causes many problems in the weldability such as a narrow weldable current range and deterioration of mechanical properties during resistance welding. Therefore, in this study, we introduce research performed to improve the weldability of Al-Si coated hot-stamped boron steel in terms of the material and process.

Ultra-rapid resistance welding of polypropylene within 1 s by monofilament implant assistance

In this paper, an innovative ultra-rapid resistance welding process was proposed for the bonding of polypropylene (PP) plates to alleviate the dilemma of edge effect. The ultra-rapid resistance welding of PP plates was conducted under different heating time (th) and diameter (ds) of stainless-steel (SS) wire in this research, the SS wire of ds = 0.6 mm and th = 1 s was separately selected as the most suitable heat transfer implant and welding time. The edge effect was proved by the interface morphology at different positions of the joint and the thermal simulation results of COMSOL.

Discrimination of Poor Electrode Junctions within Lithium-Ion Batteries by Ultrasonic Measurement and Deep Learning

Lithium-ion batteries, which have high energy density, are the most suitable batteries for use in high-tech electromechanical applications requiring high performance. Because one of the important components that determines the efficiency of lithium-ion batteries is the electrode, the manufacturing process for this junction plays an important role in the entire production process. In particular, the process related to the resistance spot welding of the electrode is very important, directly affecting the safety of users, and greatly affecting the performance of the batteries. However, because the electrode tab is spot-welded onto the inner surface of the case, it is impossible to verify with visual testing (using the naked eye) whether the junction is well bonded. Therefore, it is very important to perform quality evaluation of the resistance welding of electrodes after completing the manufacturing process, using non-destructive testing methods. In this paper, a non-destructive ultrasonic testing technique was applied to examine the quality of lithium-ion batteries in which the negative electrode tabs were welded to the inner surface of the cell cans. The status of resistance spot welding between the electrode and the can was verified using deep-learning techniques with the experimentally acquired ultrasonic signal database.

Projection-capacitor discharge resistance welding of 430 stainless steel and 14YWT

Efforts to advance structural materials with improved properties and service life in support of next generation designs for nuclear reactor components have recently led to development of nano-ferritic alloys (NFAs) containing nano-oxides such as 14YWT. A key enabling technology to realizing the useful properties of NFAs during service involves preservation of the oxide dispersions during joining. Solid-state welding processes, such as projection-capacitor discharge resistance welding (P-CDRW) used here, are well suited for joining NFAs while retaining the oxides. Due to limitations in the supply of 14YWT NFA material, initial experiments were conducted using 430 stainless steel as an inexpensive surrogate material. The goal of the surrogate experiments was to scale suitable parameters from 430 welds to 14YWT using ratios of key properties for the two materials including flow stress at temperatures and strain rates relevant to hot working. Results indicated that weld displacement increased with increasing weld force and increasing weld energy for all other variables held constant. Weld energy appeared to have a larger effect on displacement than weld force for the sample geometry used here. Appropriate process parameters (no melting) were established for the two materials. The process window for the 430 material extended from 350 J to 600 J of energy for weld forces of 2.2 kN and 3.1 kN. Suitable parameters for 14YWT were similar in terms of energy but for force levels of 3.1 kN and 4.0 kN. Displacement for both materials ranged from 150 μm to 300 μm for welds that did not experience melting. Simple heat flow analysis confirmed that the extent of displacement was limited by the characteristic thermal distance determined from thermo-physical properties and the weld current rise time. The higher flow stresses of 14YWT relative to 430 were apparently offset by greater heating due to higher electrical resistivity near the projection tip and lesser heat conduction from the projection tip owing to lower thermal conductivity. Based on the results presented here and in our companion paper. The P-CDRW process appears capable of successfully joining the 14YWT NFA while retaining the microstructures and properties of the original material.

The Mechanical Characterization of Welded Hybrid Joints Based on a Fast-Curing Epoxy Composite with an Integrated Phenoxy Coupling Layer.

The joining of composites mostly relies on traditional joining technologies, such as film or paste adhesives, or mechanical fasteners. This study focuses on the appealing approach of using standard thermoplastic welding processes to join thermosets. To achieve this, a thermoplastic coupling layer is created by curing with a thermoset composite part. This leads to a functional surface that can be utilized with thermoplastic welding methods. The thermoplastic coupling layer is integrated as a thin film, compatible with the thermoset resin in the sense that it can partially diffuse in a controlled way into the thermoset resin during the curing cycle. Recent studies showed the high affinity for the interphase formation of poly hydroxy ether (phenoxy) film as coupling layer, in combination with a fast-curing epoxy system that cures within 1 min at 140 °C. In this study, an investigation based on resistance and ultrasonic welding techniques with different testing conditions of single-lap shear samples (at room temperature, 60 °C, and 80 °C) was performed. The results showed strong mechanical strengths of 28.9 MPa (±0.7%) for resistance welding and 24.5 MPa (±0.1%) for ultrasonic welding, with only a minor reduction in mechanical properties up to the glass transition temperature of phenoxy (90 °C). The combination of a fast-curing composite material with an ultra-fast ultrasonic joining technology clearly demonstrates the high potential of this joining technique for industrial applications, such as automotive, sporting goods, or wind energy. The innovation allowing structural joining performance presents key advantages versus traditional methods: the thermoplastic film positioning in the mold can be automated and localized, joint formation requires only a fraction of a second, and the joining operation does not require surface preparation/cleaning or structure deterioration (drilling).

Investigation and Optimization of Resistance Implant Welding of Polypropylene Sheets

Recently, the use of resistance welding in the joining of polymeric materials and polymer composites in the aviation, marine, and automotive industries has been gradually increasing. However, challenges continue in regard to improving product quality as affected by several parameters. This study focused on the effects of wire geometries and wire diameters on the characteristics of polypropylene (PP) sheets united by resistance implant welding. Here, PP sheets manufactured by the injection molding method were joined via the resistance upset welding method with three different wire geometries, including spiral, wavy, and M-shaped, and two different wire diameters of 0.3 and 0.5 mm. Mechanical properties, morphological properties, and heating characteristics were examined. The results showed that wire diameter and wire geometry affected amount of heat formation in the weld zone and, therefore, weld performance in terms of the mechanical properties. The results obtained from the study can be used as a reference in similar applications.

Anomaly detection methods for infrequent failures in resistive steel welding

Many industrial plants encounter infrequent faults and failures (anomalies) during operation which generate significant increases in costs. Modelling and detection of these anomalies is challenging due to unbalanced (few anomalous observations) and unlabeled (no class information) historical data. Previous works require large, labeled, and balanced training datasets which are typically not available in industry. This work relies solely on data taken from normal plant operation to construct anomaly detection models.Single-class neural network autoencoders and principal component analysis are developed as quality monitoring and anomaly detection solutions for resistive seam welding. Monitoring models of the welding process, which facilitate anomaly detection through interpretable metrics, are constructed from easily obtained normal welding process data. No examples of poor-quality welds, nor designed experiments, are required. The methods are applied to industrial data from a steel galvanizing line which encounters infrequent yet costly weld failures. It is shown that these two monitoring approaches are capable of robustly detecting infrequent weld-breaks, without requiring examples of weld failures or poor-quality welds, using only online industrial production data from normal welding operation. Additionally, the monitoring metrics, visualizations, and root-cause analysis functionality also provided by these models are demonstrated.

Analysis of Welding Technology about Bimetallic Clad Pipelines

Butt girth welding was a knotty problem for future application of bimetallic clad pipelines. At present, there were two kinds of problems: 1) To decide whether to use a variety of alloy welding procedure or to use corrosion resistant alloy full welding procedure; 2) After selecting the procedure, what kind of welding material should be equipped. In view of the above problems, taking 316L SS or 2205 DSS clad pipe as an example, welding process design and experimental analysis were conduted in this paper. Analysis of welding process from theory, standard and practice pointed out the control of welding hardness under different welding materials and procedure and directional suggestions of welding for bimetallic clad pipelines were provided. Futher the hardness distribution and CVN absorbed Energy test results of different welding processes showed welding quality could be guaranteed only when ENiCrMo-3 welding material was chosen for the whole weld.

Low Electric Power Resistance Welding of Chrome Steel by Inserting Low Boiling Point Compound

Automobile bodies are assembled by resistance spot welding of 3,000 to 6,000 points per car, mainly on pressed thin plate components. In this study, a low-power, high-strength joint was investigated by inserting a low boiling point compound into the joint interface and using the vaporization and volume expansion of the compound caused by heat during resistance welding to break down the oxide film and increase the area of strong joint. As a result，higher tensile strength was obtained than that of the non-inserted joint.

Robotic MIG welding process parameter optimization of steel EN24T

In the early 1960s, initially, industrial robots were employed in welding, painting, assembly, etc. Robotized welding has progressed at a breakneck pace, and at present, it is one of the essential applications for industrial robots. Robotic welding is conducted by robots that automate the welding process by performing the weld and handling welded components. Robots are highly adaptable and utilized in several welding procedures, including resistance and MIG welding. In this study, the KuKa KR-10 robot is used for performing the MIG welding. The effect of welding process parameters like voltage, current, welding speed, and wire feedrate is studied, and the experiments were performed to investigate the joint strength and hardness. It is observed that the voltage and current had a significant role in forming sound welding joints. Low wire feeding rate with high welding speed causes improper welding joint. ANOVA method investigates the significance of the variation of process parameters on response, while the TOPSIS assigns the specimen according to its performance score.