Showing papers on "Spot welding published in 1980"

Controller for spot welding

Abstract: A controller for a spot-welding machine compares the temperature evolution at a site at which a spot weld is being made to a standard thermal history stored in a digital read/write memory in controlling the welding current for the weld. Standard thermal histories can be generated and written into the memory as needed by an operator of the welding machine to take into account changes in operating conditions. The temperature evolution of the spot-welding operation is monitored by detecting radiant energy whose intensity provides a measure of a temperature of the weld. Phosphorescent radiation from a thermographic phosphor located in a welding tip of the welding machine and thermal infrared radiation are preferred for monitoring the temperature evolution of the spot-welding operation.

Sealed bags of plastic materials

Abstract: A method of sealing a sheet of woven ribbons of heat sealable plastics material to an article which may be another sheet of said plastics material comprises applying a regular pattern of ultrasonic spot welds between said sheet and said other article. The pattern of ultrasonic spot welds comprises at least two rows of welds offset with respect to one another so that the welds fall on different parallel ribbons of the sheet and in one preferred embodiment welds or adjacent rows are sequentially staggered by the breadth of one ribbon so that welds of each row form repeating diagonal lines, the diagonal lines extending between the top and the bottom row. The method is especially suitable for use with woven oriented plastics material. The invention includes a bag at least one of whose seams is formed by this ultrasonic spot welding method. A particular bag is a gussetted bag in which seams along at least the bottom edges of the gussets are formed by the ultrasonic spot welding technique.

Control of welding energy flux density

Abstract: An electrical resistance spot welding system and method is disclosed. The system has adjustable output power circuitry for applying electrical heating energy to a weld site by way of weld tips, in accordance with a welding operation. An energy monitor senses instantaneous accumulated energy applied during the welding operation, and terminates the operation when an adjustable predetermined total energy has been applied. Other circuitry monitors applied welding voltage, and derives therefrom a signal which is a function of the energy density per unit area applied at the weld site. Circuitry responds to the energy density sensing to control the energy monitor and the power circuitry to govern the total energy applied in the welding operation. As weld energy flux density decreases, such as happens when weld tips spread or "mushroom", total applied energy is increased, compensating for weld tip changes, thereby holding the amount of applied energy per unit of weld site area relatively constant from one welding operation to another.

Sizing of Spot Welds by Elastic/Plastic Analysis

Abstract: A widely used quality control test for spot welds is the cross tension test in which welded pieces are forced apart. Depending on the relative size of the weld diameter and sheet thickness, failure occurs by either the pulling of a slug of metal or by cracking across the weld junction. This paper uses a combined fracture mechanics/plasticity analysis to predict a rational basis for weld size selection.

Spot welding method of bonded composite material

Abstract: PURPOSE:To make possible spot welding free from any hindrance by performing the spot welding through the resin layer between two sheets of metal plates sandwiching the resin layer of the bonded composite material after letting the both metal plates contact with each other through punching of the metal plate on one side hereby electrically conducting between the metal plates. CONSTITUTION:The metal plate 11 of a bonded composite material 10 consisting of upper and lower metal plates 11, 12 and an intermediate resin layer 13 is punched with a punch 100. The depth of the punch is enough with about the depth at which the circumferential edge portion 11' of the punched hole of the metal plate 11 contacts the metal plate 12. Electrodes 21, 22 are disposed in this worked portion and spot welding is done to obtain a fusion-bonded part 20. In this case, forming the fusion-bonded part 20' by disposing them in the positions other than the punched portion like electrodes 21', 22' and performing spot welding is equally well. According to this method, there is no need for particularly increasing current despite the presence of the insulation resin layer.

Automatic dressing of resistance spot welding electrodes - where milling cutter reshapes electrodes, which are then re-polished via rotating polishing disk

Abstract: Electrodes are carried by a manipulator and, after an initial period of use (I), they are polished. After a second period of use (II), they are re-shaped and polished. The pref. dressing appts. consists of a combined unit provided with a polishing disk and a milling cutter, both of which are carried by a spring mounting, e.g. a metal-elastomer bush. Alternatively, the dressing appts. may consist of two separate units, one fitted with a polishing disk whereas the other is fitted with a milling cutter. Both the disk and the cutter are carried by spring mountings. Used e.g. on multi spot welding machines employed for welding metal sheet coated with Zn which contaminates the electrode surfaces, where the electrodes are periodically milled and polished.

Arc spot welding method

Abstract: PURPOSE: To prevent the burn-through and shrinkage cracking of weld zones and the generation of pinholes by making main welding and crater welding in a relatively short time, and interposing a long pause time between said welding times in MIG type arc spot welding CONSTITUTION: In superposing two sheets of steel sheet works 1 of 06W12mm thicknesses and subjecting these to MIG type arc welding, the main welding 2 of a relatively short time T 1 of about 05sec by main welding current I 1 is carried out, after which crater welding 4 of a relatively short time T 3 of 03W04sec by crater welding current I 2 is carried out after a pause time of a relatively long time T 2 of 10W11sec The generation of burn-through in the weld zone 5 of the works 1 is prevented, and the superior welding free from pinholes and crater cracks is accomplished COPYRIGHT: (C)1982,JPO&Japio

Welding method of rotary type spot welder for reinforcing steel cage knitting machine and its device

Abstract: PURPOSE:To perform spot welding of longitudinal steel and auxiliary steel uniformly and exactly extending over the whole circumference of the reinforcing steel cage, by using the welding electrode of the reinforcing steel cage knitting machine of the electrode rotary type for spot welding as the pin supporting method and mounting a counter-weight on the opposite side of the electrode. CONSTITUTION:The end plate 1 is drawn in the direction of (a) with the draw gear 17, and at the same time the hollow rotary body 10 is rotated in the direction of (b) with the driving gear 4. When the longitudinal steel group 2 mounted to the end plate 1 is being moved in the direction of (a), the auxiliary steel rewinding machine 16 which is fixed to the hollow rotary body 10 is rotated around the longitudinal steel group 2, and the auxiliary steel 3 which is rewinding is wound around the outer circumference of the longitudinal steel group 2 with a uniform pitch. On this auxiliary steel 3 is rotated the spot welding electrode 155, and spot welding is carried out for the contact part of the auxiliary steel 3 and the longitudinal steel 2. In this case, the electrode 155 is supported by one end of the supporting material 153 which is coupled with the setting material 151 with a pin, by use of a spring 152, a counter-weight 156 is mounted on the opposite side of the electrode 155, the electrode 155 is pressed against the welding part with constant force due to balance to the spring 152, and spot welding is performed stably.

Electrode for spot welding

Abstract: PURPOSE:To prevent the deformation and cracking of the captioned electrode obtained by fitting the tip body composed of W, Mo or thier alloy to a holding ring having relatively high strength and toughness and prevent the zonc deposition at the welding of galvanized steel plates. CONSTITUTION:Particles of W, Mo or their alloy together with a binder, if necessary, are packed in the holding ring 24 composed of the metal having relatively high strength and toughness in the temperature range from ordinary temperature up to the maximum rising temperature of an electrode tip 21, e.g., SUS630 steel being precipitation-hardening type stainless steel as a die and the entire part is heated while the packing in being pressed from the axial direction, whereby the tip body 25 is integrally fitted in the ring 24 to form the electrode tip 21. The protruding part of the ring 24 of this tip 21 is fitted into the annular groove 26 of the electrode body 22 composed of copper or copper alloy, whereby the electrode for spot welding is constituted.

Non-destructive testing method and apparatus for spot welds

Abstract: The present invention relates to method and to an apparatus for the non-destructive testing of spot welds and the determination of the diameter of a spot weld. The testing method comprises subjecting the welds (2) to a mechanical test using a pneumatic hammer and during the test the so-called "stuck" welds are destroyed. The remaining welds then undergo a punctiform inspection using a rheometric method. This method consists of creating a potential difference between the supply electrodes (10), of which there are even numbers in contact with the weld (2). Measuring electrodes (8) located in the vicinity of the supply electrodes make it possible to obtain a resulting quantity of the different voltages measured. After calibrating the resulting value of the voltages makes it possible to deduce therefrom the diameter of the weld and consequently its efficiency. Application to the determination of the diameter of a spot weld.

Fatigue strength of multi-spot welded joints

Abstract: This investigation is carried out in order to establish an estimation procedure of fatigue strength under tensile shear load of multi-spot welded joints arranged in perpendicular to the load direction, by using maximum load vs. number of repeated cycles curve of single-spot welded joint which has the same nugget diameter with those of multi-spot welded joints. From this purpose, a hypothesis which is able to connect fatigue strength of multi-spot welded joints and that of equivalent single-spot welded specimen is set up and its experimental verification is carried out using spot welded specimens in mild steel, high strength steel and commercially pure aluminum. It becomes sure that the hypothesis holds good, using results of strain measurement in the neighborhood of each spot weld. (Author)

Resistance spot welding method for aluminum alloy thin plate and soft steel plate

Abstract: PURPOSE: To perform welding with excellent breakaway strength by interposing an aluminum thin plate or aluminum alloy thin plate between an aluminum alloy thin plate and soft steel plate to be connected, then the interface is welded by employing spot welding CONSTITUTION: The size of an aluminum alloy thin plate interposed between an aluminum alloy thin plate and soft steel plate should only be greater than a nugget diameter, so about ≥5W10mm diameter or one side of square is available Its thickness should be about ≥01mm at a minimum, effectively about 03W06mm Namely, when pure aluminum is used, its thickness is preferably about ≤06mm and when an aluminum alloy thin plate is used, on the other hand, its thickness is favorably about ≥03mm is desired COPYRIGHT: (C)1981,JPO&Japio

Spot welding gun - with pressure compensating line joining piston actuators for each electrode

Abstract: Spotwelding gun has a fluid-pressure actuator for each of the two electrodes. The pistons operating the electrodes move in the opposite direction and their approach stroke chambers are connected to a common pressure medium source to compensate the pressure exerted by them. Arrangement saves the additional weight of mechanical compensating devices to absorb any uneven surfaces on a workpiece. This extra weight is important if the gun is used by a robot. It automatically compensates irregularities in any welding position.

Resistance spot welding method

Abstract: PURPOSE:To perform spot welding of plates to themselves with a small-size device by inserting an insert having protrusions on both sides between an upper plate and lower plate and performing resistance spot welding. CONSTITUTION:An insert 3 is inserted between an upper plate 1 and lower plate 2 and these are pressed between upper and lower electrodes 6, 7, through which current is supplied. Since heating and melting occurs at the protrusions of the insert 3, the upper plate 1, insert 3 and lower plate 2 fusion-bond, thereby forming fused part 4 and fused part 5 respectively. The upper plate 1 and lower plate 2 are bound by way of the insert 3. The indentation depth generated in the upper plate 1 and lower plate 2 by the upper electrode 6 and lower electrode 7 becomes extremely small because the volume of the insert 3 is added to the nugget part and this increases the volume of the nugget. In case the upper plate 1 and lower plate 2 being the welding works are aluminum alloy or copper alloy requiring large current, this invertion is extremely effective.

Spot welding machine

Abstract: PURPOSE:To achieve the less manpower and higher working efficiency in spot welding of two-joint arm type by moving a welding head through manual operation and having the coordinates thereof stored then performing the playback numerical controlling of repeating the work automatically by the stored numerical values CONSTITUTION:First, a manual operation knob 11 is operated in the direction of the welding position by the first manual operation to drive servo motors 1, 2 and slew and move the 2nd arm 3 and 1st arm 4 Thence, the movements of the arms 3, 4 are converted to pulse signals by the 2nd and 1st position coders 7 and 8 respetively and the pulse signals are sent to a memory device When a welding head C arrives at each weld point P, the wire length L and angle of inclination beta are stored as pulse numerical values Next, a changeover switch is automatically changed over and the motors 2, 1 are run based on the foregoing stored numerical values so that the arms 4, 3 slew the head C until it reaches the specified position Next, this head C is positioned and the head C is lowered by the command from the welding head control unit, whereby the spot welding is performed between upper and lower electrodes (between tables A, B and head C)

Method and device for the non destructive testing of spot welds

Abstract: not available for EP0030889Abstract of corresponding document: US4368422The present invention relates to method and to an apparatus for the non-destructive testing of spot welds and the determination of the diameter of a spot weld. The testing method comprises subjecting the welds (2) to a mechanical test using a pneumatic hammer and during the test the so-called "stuck" welds are destroyed. The remaining welds then undergo a punctiform inspection using a rheometric method. This method consists of creating a potential difference between the supply electrodes (10), of which there are even numbers in contact with the weld (2). Measuring electrodes (8) located in the vicinity of the supply electrodes make it possible to obtain a resulting quantity of the different voltages measured. After calibrating the resulting value of the voltages makes it possible to deduce therefrom the diameter of the weld and consequently its efficiency. Application to the determination of the diameter of a spot weld.

Spot welding gun - has pivoted bracket moved by power cylinder to clear workpiece

Abstract: Spot welding gun. esp. for use in flow lines of the motor car body production has the upper welding electrode attached to a bracket which can be swivelled relative to a guide shaft inside a mounting block. At the end opposite to the welding electrodes, a double-acting horizontal power cylinder is attached below the double-acting vertical welding cylinder, to turn the bracket through an angle. The welding gun operates reliably and with little noise. The turning of the welding gun clear of the workpiece is independent of the clamping movement and an interlock can ensure that clamping is possible only after the welding gun has been returned to the welding position.

Insertinggtaking out equipment of intermediate electrode for resistance welding

Abstract: PURPOSE:To adjust the height of an intermediate electrode and prevent welding quality from its deterioration by sliding one of intermediate electrodes which are stacked in 2 layers. CONSTITUTION:A plural number of intermediate electrodes 5 set on a guide roller 8 and a roller 9 are inserted into a welding object 7 located on a supporting stand 6 by means of a moving platform 11 provided with a hooking metal 10. By a cylinder 12. the upper side of 2 layer intermediate electrodes 5 is made to slide and the height of the intermediate electrode 5 is rised up to a specified dimension. A resistance welder 13 performs spot welding of the welding object 7 up to the position of the upper electrode 16. After welding, the welding object 17 is restored to the previous position, the cylinder 12 is operated in the opposite direction to lower the height of the intermediate electrode 5, which is taken out by the moving platform 11. This method is applied to resistance welding of panel material of a steel sheet and the like.

Spot welding machine

Abstract: PROBLEM TO BE SOLVED: To drastically reduce the burning surface area of a coating film and to reduce the occurrence of strain by controlling repeatedly and intermittently preheating current flowing through an electron switch in a current course connected to a contact member contact-connected to the metal exposed surface area. SOLUTION: Welding current for original welding is started to flow through a second welding electrode tip 27 set so as to face to broken position of the coating film 24b of the member 24 to be welded by burning-breakage of the coating film 24b through the members 23, 24 to be welded from a first welding electrode tip 22. This current is detected by an ammeter 29, and when this detected current reaches a suitable value for the welding, the intermittence is stopped by an on-off control means 31 of an electron switch through a release means 32 to control the electron switch in the perfect off-state. By this method, the current flowing through a contact clamper 26 and a cable 25b is interrupted and the welding current is allowed to flow only through the first welding electrode tip 22, members 23, 24 to be welded and the second welding electrode tip 27 to effectively execute the welding.

Tank for oillfilled electrical machine

Abstract: PURPOSE:To obtain a tank which does not occur deformation by welding ribs for heat sink placed at the outside of vertical slits which are made by cutting a sheet metal plate in vertical way at an intervals wherein spot welding is made for reinforcement bars placed at the inside of the plate and running in horizontal way and the position of spot weld is the middle point of each vertical slit. CONSTITUTION:Plural slits are provided for a sheet metal plate in vertical direction at predetermined interval and ribs 5 for heat sink are welded by coating each slit with the plate and by protruding the ribs 5 at the outside of the slit. Then, the plate is bent in wavy shape by placing the ribs 5 outward to serve as a tank for oil-filled electrical machine. At that time, plural reinforcement bars 6 provided in the tank are not placed at the upper end 5a of normally installed ribs 5 but provided at the inside of the tank so that the bars may meet at right angles with the slits and the bars are adhered to the plate by spot weld 10. In this way, the strength becomes strong and oil leakage, etc. will be eliminated. Furthermore, easy workability will remarkably be facilitated.

Non-ferrous metals

Abstract: Aluminium and aluminium alloys may be joined by arc-fusion welding, resistance welding, solid-phase welding, brazing and adhesive bonding. Low-melting aluminium-zinc solders have also been used to a limited extent. Fusion welding was first accomplished by the oxy-acetylene process but is now carried out by means of GTA and GMA welding and sometimes using coated electrodes. The power source for GTA welding is usually an a.c. transformer with high frequency re-ignition. When the electrode is positive a non-thermionic cathode (see Section 3.5.2.1) forms on the aluminium surface; the cathode spot wanders over the weld pool surrounding plate surface and removes most of the oxide. With d.c. electrode-positive most of the arc heat is absorbed by the tungsten electrode, and at normal welding currents this melts and is difficult to manage. With a.c. welding, a compromise is possible; during the electrode-positive half-cycle the oxide film is removed while during the electrode-negative half-cycle the workpiece is heated. However, d.c. electrode-positive may be used for special purposes. Welds may also be made with d.c. electrode-negative using helium as the shielding gas, but this too is for special applications. In general GTA welding is applicable to lighter sections than GMA welding.

Tig arc spot welding method

Abstract: PURPOSE:To prevent the fluctuations of arc length, perform perfect penetration in a short time and form the fusion-welded part of high quality by performing arc voltage tracing controlling after the welding arc stabilizes or after molten metal pool is formed by the welding arc. CONSTITUTION:Even if the spacing between the electrode 1 end and the welding work 2 surface changes, the voltage of an arc 3 is so controlled as to automatically become of a fixed value. Namely, when the spacing between the electrode 1 end and the work 2 spacing becomes small and the output of an arc voltage detector 16 becomes smaller than the output of an arc voltage setter 18, the spacing between the electrode end and the welding work surface is increased. Conversely, when the spacing increases and the output of the detector 16 becomes larger than the output of the setter 18, the electrode end is approached to the welding work surface. According to this method, even when the true arc length changes along with the progression of welding, the electrode 1 is driven in follow-up to this and the arc length is maintained constant and therefore, always optimum arc length may be provided and the melting range may be limited narrow.

Method and apparatus for spot welding of multiple spot work

Abstract: PURPOSE:To shorten the working time and restrict runaway phenomenon, by welding with two welding heads from the both ends of multiple spot work successively to the middle, shifting one head to the middle, then subsequently welding while moving in the same direction. CONSTITUTION:All spot rows of multiple spot work W are divided into two groups, and welding is started simultaneously with right and left welding heads from the corresponding spot (a or e) of row L1 and row R1 at the both ends of the work W. For example, when starting spot-welding from L1a and R1a, the both welding heads are moved toward the middle of the work W in the direction of arrow S. By welding an arbitrary number of spots by this preliminary process, one head is moved to a next spot R3a, while the other head is moved to spot Lna corresponding to R3a in the middle spot row in the left spot group. After welding the both spots at the same time, the remaining spots are welded, for instance, by moving the both heads in the same direction as shown by the arrow of broken line. In the case of work having an odd number of spot rows, the final one spot row is welded by a single head.

Spot welding equipment

Abstract: PURPOSE:To weld the plural places of the pocket part of the works by one unit of equipment without increasing electrode displacements by providing the mechanism of turning a welding gun about the portion near the electrodes with respect to the machine body. CONSTITUTION:Parts such as rear end panel (b) and underbody (c) of an automobile are positioned between the electrodes 7 and 8 of a welding gun 3. A base frame 2 is lowered to subsequently spot-weld the central part of the welding portions of the parts (b) and (c) at the specified pitch. This welding is accomplished by intermittently moving the welding gun 3 in a vertical state in the width direction. When the welding gun 3 reaches the portions near the pocket part of the rear fender, the welding gun 3 is turned about the pin 14 by turning of a gun-mounting frame 11 and welding is done in the state that it is inclined to the specified angle.

Brazing method in nonnoxidation atmosphere

Abstract: PURPOSE:To perfectly perform brazing and improve working efficiency and the quality of brazed parts by tentatively fixing the material to be brazed to a base metal by spot welding then supplying brazing material and heating the material in a non-oxidation atmosphere to melt and allow the brazing material to penetrate in clearances. CONSTITUTION:The material to be brazed 11 is tentatively fixed to an arbitrary position of a base metal 12 by spot welding 16. Brazing material 13 is fitted to the outside of the brazing part in contact with the clearance between the brazing material and base metal 12 and the assembly is heated in a non-oxidation atmosphere. Heating causes the brazing material to melt and this molten material penetrates in the clearance between the material to be brazed 11 and the base metal 12 and fills said clearance. Thereafter, the assembly is cooled to allow the brazing material 13 to harden. This method obviates moving of the base metal 12 and the material to be brazed 11 during their handling and enables desired places to be perfectly brazed.

Spot welding method of steel plate

Abstract: PURPOSE:To spot-weld steel plates without applying any pretreatment at all by holding the weld section of the superposed steel plates to be welded between the electrodes of a spot welding machine under pressure and applying ultrasonic vibrations thereto then supplying welding current between the both electrodes. CONSTITUTION:The portion where exists the superposed faying point of the plate materials to be bonded is placed on a cradle or electrode and is held under required pressure between the both electrodes or between the electrode and cradle, after which ultrasonic vibrations are applied thereto. Thence, welding current is supplied between the both electrodes or between the electrode and cradle through the plate materials to be welded and the superposed plate materials are spot-welded. Here, the plate materials to be welded are rubbed with each other by the application of the foregoing ultrasonic vibrations and the film of precoating, etc. is melted by the friction heat and is expelled to outside the faying point. In the case of rusted plates, the ultrasonic vibrations remove rust and flatten the finely undulated surfaces having been produced on the surface through rust formation to crean metal surfaces, thus the rust and removed metal powder may be removed to outside the faying point.

Structure of conductor at valve sealing part

Abstract: PURPOSE:To obtain stable strength of welding by welding a metal foil on the round surface of a leading rod which has a flat surface part on a part of the end circumferential surface and a flat surface part and round surface part on the remaining surface. CONSTITUTION:The second flat surface part 5 which is opposite to the first flat surface part 2 of a leading rod 1 made of molybdenum etc is formed by the length L4, leaving a prescribed distance L3, and the length L3 of the round surface 3 is limited in a fixed range, into 0.1-1.5mm. Accordingly, even if the values L1 and L4 are made longer as required in relation to spot welding work, at least welding range is limited. The flat surface part 5 described above may be split into two parts. Thus, when foil 4 made of for example molybdenum is welded onto the leadig rod 1, stable strength of welding can be obtained.