Resistance welding is one of many methods of fastening two or more pieces of metal together. It works by contacting copper alloy electrodes to the sheet surfaces, whereby pressure and electric current are applied and heat is generated by the passage of current through. It is a thermoelectric process in which heat is generated at the interface surfaces of welding plates due to electric. Today we will learn about resistance welding principle, types, application, advantages and disadvantages. There are 30006000 spot welds in any car, which shows the.
In electric resistance welding erw methods, a high current is passed through the metal pieces to be joined together and the heat is produced due to the resistance in the electric circuit. This specification is intended to replace the following documents. Spot welding is a type of electric resistance welding used to weld various sheet metal products. This specification provides the general resistance welding requirements for aerospace hardware. The metallic objects have various electrical and thermal properties that make it possible for the resistance welding process to occur.
Spot welding is a resistance welding process that is used primarily for welding two or more metal sheets together by applying pressure and heat to the weld area. It is an efficient joining process widely used for the fabrication of sheet metal assemblies. Automotive adaptation concerns high current demands electrode life use of pretreatments lives of resistance spot mash welding of cu wires for electric car. In both cases, the welding parameters had to be carefully controlled in order to obtain spot welds with an adequate shear tension strength for the.
Therefore, in recent years, a lot of efforts have been made in. A comparison of ac to inverter dc resistance spot welding and. It is a thermoelectric process in which heat is generated at the interface surfaces of welding plates due to electric resistance and a controlled low pressure is. Welding is a basic manufacturing process for the manufacture of components or parts with noble mechanical properties. The initial results showed that the response time of this system was unstable. Resistance welding is a liquid state welding process in which the metal to metal joint created in liquid or molten state. Test methods for evaluating the resistance spot welding. This bulletin provides guidelines for repair shops that wish to use squeeze type resistance spot welding or simply, spot welding as an alternative to mig plug welding when performing collision repair procedures. A video describing the resistance spot welding process. The name resistance spot welding derives from the fact that the resistance of the workpieces and electrodes are used in combination or contrast. This document presents standard test methods for evaluating the resistance spot welding behavior of automotive sheet steels.
They are critical in understanding the formation of the structures of a resistance spot welding rsw welded joint, the mechanisms of defect formation, and their impact on a welds strength. Spot welding is used in the manufacturing of automobiles, aircraft, steel household furniture and steel containers. So, can technology solve resistance welding problems. A comparison of ac to inverter dc resistance spot welding and the effects on dualphase 600. Experimental study shunting in resistance spot welding is affected by the process variables involved and caution must be taken when welding with narrow weld spacing by b. This installation, operation, and maintenance of arc welding equipment and the employment of. It includes, but is not limited to, resistance spot and resistance seam welding of aluminum, magnesium, iron, nickel, cobalt, and titaniumbased alloys.
A current is then passed between the electrodes, sufficient heat being generated at the interface by. The electrodes have to be able to reach both sides of the pieces of metal that are being joined together. The welding electrodes are motordriven wheels rather than stationary caps. Weldhelp resistance welding troubleshooting guide g. As a result, the remainder of the trials were done using a more conventional. Additionally, janda has a full line inventory of all major brand controls, transformers, welding guns, scrs, foot switches, cables, weld checkers, water chillers, and more. When autoplay is enabled, a suggested video will automatically play next. This document is not an application manual and does not contain a complete statement of all factors pertaining to those topics. A comparison of ac to inverter dc resistance spot welding. Spot welding is the type of resistance welding when the thermoelectric heat is generated, sequentially, at a usually large number of isolated points spots, where the mating surfaces are pressed together by an external force during the whole welding process. Dec 12, 2019 resistance seam welding is a variation on resistance spot welding. Resistance welding is one of the oldest of the electric welding process is used by industry today. This study introduces rapid bonding of pbte and ni plate using a currentcontrolled spark plasma sintering technique.
Normally, the parameters monitored for weld quality detection are classi ed into two types. Dec 19, 2008 a video describing the resistance spot welding process. The presentation of the physical background of the resistance welding process. Pdf this paper presents an overview of resistance spot welding control. One general criterion of resistance spotwelding is that the weld shall have a nugget diameter of 5t 12, t being the thickness of the steel sheet. Janda manufactures resistance welding equipment and has the nations largest in stock inventories of electrodes, holders, accessories, and copper alloys. Diameter of the electrode contact surface should be.
A particular spot welding machine will be able to hold only a certain thickness of metalusually 5 to 50 inchesand although the position of the electrodes can be adjusted, there will be only a limited amount of movement in most electrode holders. Shunting effect in resistance spot welding steels part 1. The resistance of the base metal to electric current flow causes localized heating in the joint and the weld is made. Handbook for resistance spot welding warning this document contains general information about the topics discussed herein. This type of weld gun uses a lead screw and an electric motor to create the weld force. The weldhelp resistance welding troubleshooting guide is written for operators and engineers to help diagnose and solve common spot welding defects and issues, projection welding and seam welding applications. Thus, a spot weld made in two sheets, each 1 mm in thickness, would generate a nugget 5 mm in diameter according to the 5t. Spot and seam, march 28, 1978 amsw6858a, welding, resistance spot and seam, april 1, 2000. Resistance spot welding has been widely used for joining sheet metals, especially in automotive and aerospace industries. Resistance spot welding rsw is a major sheet metal joining process in many industries, such as the automobile, domestic appliances, air craft and space craft fabrications. There are three independent parameters in configuring seam welding machines. Resistance spot welding is accomplished when current is caused to flow through the electrode tips and the separate pieces of metal to be joined. Figure 3 approximation of current path during welding to evaluate the 23 resistance.
Basic level prepared by lutz dorn, technische universitat, berlin. The goal of good resistance welding is to focus the heat generated close to the weld interface at the spot where the weld is desired. Resistance spot welding resistance spot welding definition. Resistance spot welding rsw is a common and largescale joining method in several manufacturing industries indicating significant potentials of efficient. Resistance welding an overview sciencedirect topics. An understanding of the resistance welding process is basic to making good welds. Resistance seam welding is a variation on resistance spot welding. Resistance spot welding rsw is regularly used as a successful joining method for a variety of jobs in the automotive and. Review on techniques for online monitoring of resistance. The process of spot welding for attaching body panels and components has.
D protect yourself and others from flying sparks and hot metal. Resistance spot welding is the dominant welding process in the automotive. It provides job opportunities to many people at various levels of the economy. The weld is made by the combination of the heat, pressure and time.
Specification for resistance welding for aerospace applications. Apr 15, 2017 today we will learn about resistance welding principle, types, application, advantages and disadvantages. A survey of the literature on resistance welding refs. The trend in many of the more recent programs is to use inverter dc. It is known that, when material resistance against weld current is increased, heat formation also increases. The document contains a number of tests and test methods useful in determining the resistance spot welding performance of coated and uncoated automotive sheet steels of all strength levels and compositions. Figure 2 schematic illustration of spot welding parameters and electric field 19 patterns in the workpiece during welding. Resistance welding helps two pieces of material, usually metal, bond together. Temperature distribution study in resistance spot welding 201 material resistance. Once sufficient resistance is generated, the materials set down and combine, and a weld nugget is formed. Applicationspecific measures, such as the diameter of the welding spot, determine the quality of the joint. For additional information regarding the metallurgy in resistance spot welding steels and. But, as differences between sheet thickness and temperatures are not very high, a high change is not observed in cooling rates. Accidental contact of electrode to metal objects can cause sparks, explosion, overheating, or fire.
Kuka resistance spot welding often just called spot welding is a costeffective joining technology that continues to be very popular in the automotive industry where high reproducibility and automation are essential criteria. Temperature distribution study in resistance spot welding. Pdf overview of resistance spot welding control researchgate. Advances in the resistance spot welding of aluminum. D do not spot weld where flying sparks can strike flammable material. Resistance welding is one of the simplest, lowest cost, surest means of metal joining. Resistance welding is a fusion welding process that requires the application of both heat and pressure to achieve a sound joint. Check and be sure the area is safe before doing any welding. Resistance spot welding resistance welding is a thermoelectric process where heat is generated at the interface of the parts to be joined by passing an electrical current through them or a precisely controlled time and under a controlled pressure also called force.
As the name implies, it uses the resistance of the materials to the flow of current that causes. All resistance welding spot welding, seam welding, projection welding, etc. The flying sparks, hot workpiece, and hot equipment can cause fires and burns. Resistance welding is a process for fastening metallic objects together. This method resembles welding and, in particular, resistance spot welding rsw. Since the welding control provides control of both welding current and machine motion, it must. Optimization of spot welding process parameters for maximum tensile strength manoj raut 1 and vishal achwal corresponding author. Mar 30, 2018 resistance welding helps two pieces of material, usually metal, bond together. Due to the inaccessibility of nugget in inspection process, usually destructive tests are used to assess weld. Figure 3 approximation of current path during welding to evaluate the 23 resistance between electrode tips. Specification for resistance welding for aerospace. The automotive industry is now one of the most important sectors of all developed economies.
An economical joining process in sheet metal processing spot welding of a front end source. Spot welding or resistance spot welding is a type of electric resistance welding used to weld various sheet metal products, through a process in which contacting metal surface points are joined by the heat obtained from resistance to electric current. Resistance spot welding rsw is one of the common assembling process of thin metals. The welding control may be thought of as the brains and the machine as the muscle of the overall resistance welding system. In general, the highest resistance results in the highest heat assuming that the resistance welding power supply can produce sufficient energy to overcome the resistance. In general, the highest resistance results in the highest. Spot welding or resistance spot welding is a type of electric resistance welding used to weld various sheet metal products, through a process in which contacting metal surface points are joined by the heat obtained from resistance to electric current the process uses two shaped copper alloy electrodes to concentrate welding current into a small spot and to simultaneously clamp the sheets. Electrically, metallic objects have some level of resistance to the flow of electrical. Resistance spot welding uses the face geometries of the welding electrodes themselves to focus the welding current at the desired weld location, as well as to apply force to the workpieces. Resistance spot welding of aluminum 1980 state of the art cont.
The weld is made by a combination of heat, pressure, and time. However, since the formation of weld nugget is invisible in resistance spot welding, traditionally offline destructive test is applied for inspection of the weld quality, which is costly and inefficient. Introduction to spot welding working principle of projection welding introduction to spot welding spot welding is one of the type of welding processes. Resistance welding is a thermoelectric process where heat is generated at the interface of the parts to be joined by passing an electrical current through them or a precisely controlled time and under a controlled pressure also called force. The machines, controls and fixtures are only the tools necessary to help make the weld. Introduction to spot welding working principle of projection. The simplest form of the process is spot welding where the pressure is provided by clamping two or more overlapping sheets between two electrodes fig.