Showing papers on "Spot welding published in 1984"

Resistance spot welder process monitor

Abstract: A multivariable process monitor and method of monitoring a resistance spot welding process to yield instantaneous information on weld quality during the weld cycle. Sensors on the machine measure welding input variables and workpiece response variables and provide signals to a microcomputer system. A simplified analytical model of the spot welding process is incorporated in the microcomputer and is the reference for the weld quality logic that accepts or rejects the weld. Faulty welds are diagnosed and the reason displayed.

Method of and installation for spot-welding by laser beam

Abstract: A method of spot-welding by laser beam, comprising a laser beam generator (10) and at least one means receiving the laser beam and focusing it on the pieces to be welded.

Resistance spot welding gun and transformer assembly

Abstract: An assembly is provided for mounting on an end of a robot arm actuator as an integral spot resistance welding gun and transformer unit. A gun slide support bracket is connected to the transformer and serves to provide a mount for a sliding gun cylinder having a piston connected to one of the jaw electrodes. The lower jaw is removably connected to the cylinder. Roller shunts are used to provide electrical connection between secondary terminals on the transformer and the two electrodes. A proximity switch assembly is advantageously utilized to provide signals to the robot controller indicating a fully retracted position of the jaws.

Multi-point laser beam welding installation for vehicle bodies

Abstract: A multi-point laser welding installation for vehicle bodies includes apparatus for positioning the pieces to be welded, apparatus for gripping the pieces and apparatus for welding the positioned and gripped pieces at specific points. The apparatus for positioning and gripping are provided with bearing surfaces. The shape of these surfaces conforms to the shape of the pieces. The apparatus for positioning and gripping include cavity which open the pieces at right angles. The welding apparatus is fixed on the positioning and/or gripping apparatus in order to ensure spot welding of the pieces at right angles to the cavities.

Method of predicting the quality of a resistance spot weld

Abstract: During a weld period in the formation of a resistance spot weld the weld parameters are monitored. and data representIng the weld resistance curve and the power curve are acquired and stored for analysis by a suitably programmed computer. A prediction of the quality of a weld, and specifically as to whether a weld is a nugget or a sticker is made by calculating the ratio of weld energy after the onset of melting to the total weld energy, and also the ratio of the resistance drop afterthe resistance peak to the peak resistance, and then utilising the weighted sum of the energy ratio and the resistance drop ratio, as a weld quality indicator.

Resistance spot welding gun with weld quality detection feature

Abstract: A method and apparatus are disclosed for detecting weld nugget growth on a workpiece during a welding operation using a resistance spot welding gun. In the preferred embodiment, a piston rod is slidably mounted in a cylinder and is connected at one end to an electrode of the gun. The opposite end of the piston rod extends rearwardly through the cylinder and is coupled to a sensor assembly for detecting the amount of movement of the piston rod created by weld nugget growth on the workpiece during the welding cycle.

Method and apparatus for dressing spot welding tips

Abstract: A tool for dressing copper spot welding electrode tips to a desired configuration comprises a disc with opposed concave faces formed at their centers in the desired configuration of the tips and adapted to be rotatably driven by a power tool. The dressing surfaces are uninterrupted surfaces of revolution and, therefore, contain no cutting edges. In operation, the electrode tips while mounted on a welding machine are clamped against a rotating dressing tool with normal welding pressure, so that as a result of the frictional engagement of the tool with the tip, the metal flows into conformity with the tool surface. Thus, no significant amount of metal is removed from the welding tip.

Modification of silicon properties with lasers, electron beams, and incoherent light

Abstract: Lasers have long established a permanent position in manufacturing1–5 They are used to cut hard and brittle materials, to weld metallic objects rapidly and efficiently, to harden locally surfaces of metals, and to drill microscopic holes in materials as diverse as rubber and steel High power electron beams are routinely used for spot welding and to a lesser extent for cutting and drilling

Method for preventing the discoloration of areas around indentation in spot welding

Abstract: A method for preventing discoloration of the area around an indentation in spot welding is provided in which the weld zone and its surrounding area are masked with a non-oxidizing gas such as argon gas, helium gas, nitrogen gas or a mixture of argon gas and carbon dioxide gas from ambient atmospheric air and spot welding is carried out in the atmosphere of the non-oxidizing gas to prevent the discoloration from occurring at the weld zone of a metal sheet under the influence of heat during spot welding.

Weld bond method

Abstract: PURPOSE:To maintain the layer of an adhesive agent to have a uniform thickness by disposing an adhesive agent contg spacers made of thermoplastic resin between materials to be welded, expelling the adhesive agent and the spacers by the heating and pressurizing of electrodes from the outside of the materials to be welded and subjecting the materials to resistance spot welding CONSTITUTION:An adhesive agent 2 contg thermoplastic spacers 5 is disposed between materials 1a and 1b to be welded Electric current 7a is conducted between an electrode 3a and an auxiliary electrode 6 to generate heat by resistance, thereby preheating a material 7a to be welded Then the spacer 5a right beneath the electrodes 3a, 6 melts and the agent 2 increases its fluidity The agent 2 and the spacer 5a are extruded to a direction (a) by the pressing force of the electrode 3a and welding current 7 is conducted between the same and a lower electrode 3b A weld zone A is then made in the state where the agent 2 and the spacer 5a are absent and spot welding is accomplished by tight adhesion of the materials 1a and 1b Since the spacers 5 exist in the parts except the weld zone A, the thickness of the adhesive layer is controlled to an optimum thickness

Ultrasonic method for shear strength prediction of spot welds

Abstract: A novel ultrasonic method was developed to evaluate shear strength of a spot weld. This method is based on an analytical expression relating the transmission coefficient of Lamb waves passing through an aperture in solid plates to the aperture size. Simultaneously, a fracture mechanics model was introduced to correlate fracture load to the dimension of a spot weld. Consequently, the ultrasonic Lamb wave transmission coefficient was measured through spot welds and related to fracture load. There is good agreement between experimental results and model predictions. It appears that ultrasonic waves can be used to estimate shear strengths of spot welds.

Metal pretreatment for resistance spot welding of aluminum

Abstract: A process is described for preparing aluminum sheet for resistance welding, which increases the useful life of the welding electrodes used for welding the thus prepared sheet. The process comprises the steps of: (a) treating both surfaces of the sheet portion to be welded to remove the non-uniform mill finish oxide layer and provide clean surfaces, and (b) providing a thin oxide layer on one cleaned surface and a thicker oxide layer on the other cleaned surface of said sheet, thereby creating a differential in oxide thickness between the surfaces of the sheet and hence a differential in surface resistance.

Welding head for resistance-welding

Abstract: A welding head for resistance welding, in particular for spot welding, comprising a frame to which a first welding electrode is fastened in a fixed position and a carrier for a second electrode lying substantially opposite the first electrode, said carrier being movable with respect to the frame in a manner such that the second electrode can be displaced in the direction to the first electrode, the second electrode being fastened to an element which is displaceably connected with the carrier in a manner such that it can perform a movement in a direction substantially parallel to the direction of movement of the carrier.

Reliability of Spot Welds in Cold-Formed Channels

Abstract: Cold‐formed channels are joined by means of spot welds to form various configurations. They are used in typical electrical cable and conduit supports, also in power plants. The present design procedures follow AISI specifications, which gives the allowable load per spot weld as a function of the thickness of connected plates. Tests were carried out to establish the distribution of spot weld capacity. It has been found that the strength strongly depends on technology of welding. It is recommended to review the AISI provisions and specify special allowable loads for spot welds connecting cold‐formed channels. The allowable loads could vary depending on type of connection (backto‐back, side‐to‐side, side‐to‐back) and technology of welding (degree of correlation between adjacent welds).

Method of fixing end portion of laminated amorphous magnetic alloy thin belt

Abstract: PURPOSE:To improve mechanical strength by welding and fixing the end portion of laminated amorphous magnetic alloy thin belt with laser beam CONSTITUTION:A winding body 1 in outer diameter of 25mm, internal diameter of 20mm and width of 5mm is formed by winding amorphous magnetic alloy thin belt Next, the starting end (point X) and completing end (point Y) of the winding body 1 of amorphous magnetic alloy thin belt are spot-welded with the CO2 laser Thereby, only several sheets of outer side can be welded Several sheets of amorphous magnetic alloy thin belt from the surface side near the welded point fuse by the spot welding It is then crystallized and fixed Therefore, reduction of the area to be crystallized is desirable for preventing deterioration of magnetic characteristic

Seam welding method by laser welding machine

Abstract: PURPOSE:To absorb strain and to prevent wrinkling by performing spot welding at a specified pitch on the circumference of a material to be seam-welded under rotation while providing intervals on said circumference. CONSTITUTION:The entire circumference is assumed to be seam-welded by spot welding at 16 points and spot welding is performed at every three other points. More specifically if the total number of the spots over the entire circumference and the number of the inter-spot intervals during welding are satisfactorily selected, the spot positions shift each slightly and automatically in the 2nd and succeeding turns by rotating the material to be welded at a specified speed and oscillating the laser at the intervals of the specified rotating angle. The entire circumference is thus fully welded at the number of rotation equal to the number of the inter-spot intervals without spot welding >=2 times at the same point.

Continuous hot rolling

Abstract: PURPOSE:To make connection quickly and surely using simple means when spot welding butted part of the rear end of a preceding rolled material and the front end of succeeding rolled material, by specifying pointing pitch using an electrode of specified diameter. CONSTITUTION:The rear end of a preceding rolled material 1a and the front end of a succeeding rolled material 1b are butted, and the butted part is spot welded. When spot welding, plural electrodes 2 having diameter D more than 1 time of the thickness (t) of the rolled material, and pointing pitch L is set to less than 150mm.. In this case, by arranging the electrodes 2 at the same pitch with the pointing pitch L, welding is completed by one pointing.

A vacuum tube and a method for manufacturing the same

Abstract: In a vacuum tube with a window through which radiation is passed, an entrance window member is formed of radiation transparent metal, such as titanium or a titanium-base alloy. An entrance window supporting frame, which defines the window, is formed of iron or an alloy containing iron. The flat inner surface of the entrance window member is tacked to the flat outer surface of the entrance window supporting frame along the whole perimeter thereof by tack welding. An intermediate member formed of a metal containing gold or silver is interposed between the respective peripheral edge portions of the entrance window member and the entrance window supporting frame, whereby the entrance window member is finally welded to the peripheral edge portion of the entrance window supporting frame along the whole perimeter thereof in a vacuum-tight manner by continuous spot welding. The position for the final welding is at a predetermined distance from the weld zone of the tack welding. The tack welding permits continuous spot welding with use of the intermediate member without variations of welding conditions in the weld zone.

Lining method using clad pieces and a clad piece for the method

Abstract: A clad piece comprising a surface layer and a liner. the surface layer consisting of a highly corrosion-resistant metal thin sheet and superposed on the liner, and the surface layer and the liner having been united into a laminated unitary body, can be easily produced by spot welding or seam welding, and can be advantageously used for the lining of tank wall and other chemical apparatuses.

Spot welding method

Abstract: PURPOSE:To weld surely an electric wire and a base metal and to improve working efficiency by pressing a thermoplastic covered electric wire and the base metal between electrodes and heating the one electrode then conducting successively small electric current and large current thereto CONSTITUTION:The electric wire 2 in the covered state is imposed on the base metal 3 on the stationary electrode 4 The moving electrode 5 is lowered to hold the wire 2 and the metal 3 with pressure between the electrodes 4 and 5 A switch 6a is turned on to conduct electricity to a tip 5c to heat the same A switch 6a is opened and a switch 7c is closed to conduct the small current between the electrodes 4 and 5 when a conductor 2a is slightly exposed on melting of a covering material 2b The material 2b is further melted by Joule heat, by which the exposed part of the conductor 2a is expanded The large current is then conducted between the electrodes via a welding control circuit 7, by which the conductor 2a and the base metal 3 are surely welded The need for stripping the covering material is eliminated, by which the working efficiency is improved

Spot welding method

Abstract: PURPOSE:To prevent the injury of work by providing a resistance measuring instrument, measuring the electric resistance value of the work after pressurization, discriminating the pressurized state in accordance with the resistance value and conducting welding current. CONSTITUTION:The electrodes of a spot welding gun 1 are connected via cables 4, 5 to the resistance measuring instrument 6. The secondary electrode of a welding transformer 2 is separately connected through secondary cables 3 to the respective electrodes of the gun 1. Weak current is passed to the work W through the cables 4, 5 and the gun 1 from the power source of the instrument 6 and the electric resistance value thereof is measured. The resistance value R is calculated by an arithmetic means 8 and is compared with the input data of a storage means 10 to discriminate the pressurizing state. A discriminating means 9 discriminates whether the value R is within a set value or not and instructs or stops the conduction of secondary welding current. The injury of the work is prevented by the above-mentioned method.

Assembling method of automotive body

Abstract: PURPOSE:To simplify a welding and assembling line for automotive bodies without lowering production efficiency in said line by grouping the tack welded bodies into a group of plural units, feeding each set to a normal welding line and subjecting the set of plural units to normal welding. CONSTITUTION:A body fed to a line by the cooperative driving of a shuttle bar 64 operated by a driving device 13 and lifters 7-1, 63 is subjected to multi- spot welding in a tack spot welding stage 4. The bodies in an idle stage 79 having plural lifters 11, 63 are fed as a set of plural units to an additional spot welding stage 79 by means of a transfer conveyor 88 operated by a driving device 89, and are additionally spot welded by an industrial robot welding machine 76. The bodies welded in several sets of additional spot welding stages 79-81 are carried to stages 82, 83, from which the bodies are delivered by a conveyor 87 for conveyance. The difference in time in tack spot welding and additional spot welding is thus made up by the conveyance of the set of plural units in the above-mentioned way, whereby the line is united to one.

Multi-layer composite-wall panel or case structure

Abstract: The composite-wall panel or case structure comprises a wall formed by at least two shaped sheets 5, 6 which have regions in which confronting surfaces are in adjoining relation and interconnected by bonding or spot welding, and regions in which hollow bodies are formed between said confronting surfaces so as to impart a required rigidity to the structure. A method is disclosed for producing said panel or case structure. Application in the automobile industry.

Indirect welding device

Abstract: PURPOSE:To obtain a titled device for simplifying a device and its wiring, by constituting it so that it can cope with many kinds of works by installing an electrode plate connected to a movable welding transformer to one end part of a moving arm fitted to an arm of an industrial robot. CONSTITUTION:A work 4 being an object to be welded is fixed onto a gauge plate 5 on a lifter 1 by a clamper 6, arms 13, 14 of a spot welding gun 11 installed to an arm 10 of an industrial robot 19 are operated by a fluid pressure operating cylinder 12 and a piston rod 12a, and an overlapped weld part of the work 4 is pinch-held. Also, a moving arm 19 is fitted to said arm 10, and an electrode plate 22 installed to its one end part is made to press-contact to a part except the weld part of the work 4 by operation of a fluid pressure cylinder 21 and a piston rod 21a. The gun 11, a terminal 13a of the electrode plate 22 and a bus bar 36 are connected to secondary side terminals 40a, 40b of a movable welding transformer 40 by secondary cables 37, 41, and the weld part is welded by passing a welding current.

Spot welding method

Abstract: PURPOSE:To weld securely the superposed parts of a thin copper alloy sheet and an auxiliary sheet of an alloy having the electric conductivity lower than that of said sheet by superposing the latter sheet on the surface of the former sheet, and conducting electricity thereto under pressure while the rear of said thin sheet is held superposed on a thick iron alloy plate. CONSTITUTION:An auxiliary sheet 4 of an alloy having the electric conductivity smaller than that of a thin material 3 to be welded consisting of either one of phosphor bronze and beryllium copper and having a suitable thickness is superposed on the surface of said thin sheet. On the other hand, the rear of the sheet 3 is superposed on the surface to be welded of a thick iron alloy plate 2 and these sheets and plates are disposed in a superposed state between electrodes 1 and 1' for spot welding. An input is made into a welding machine to conduct electricity to the electrodes 1, 1' under the pressure exerted thereon so that three sheets of the alloy plates including the above-described plate 2, the sheet 3 and the sheet 4 are welded to one another at the contact surfaces thereof. The secure spot welding of the thin copper alloy sheet having large air permeability to the thick iron alloy plate with high quality is thus made possible.