Showing papers on "Spot welding published in 1987"

Photodermatitis due to spot welding

Abstract: SUMMARY The case of a patient with a I-year history of recurrent, severe facial dermatitis is reported. The role of ultraviolet radiation from are welding or other equipment at work in inducing dermatitis is discussed.

Method and arrangement for process control in spot welding

Abstract: A method and an arrangement for process control in spot welding are described in which the mechanical and/or electrical process variables predetermined for the welding process are monitored during the welding and each change in the process variable within the welding operation can be readjusted via several manipulated variables. The welding process is subdivided into several areas for the control, an evaluation scheme being allocated to each of these areas. The curve behaviour for various materials and dimensions is determined on actual components and stored. Calibration of the welding machine is dispensed with.

Ultrasonic method and apparatus for spot weld control

Abstract: Ultrasonic transducers spring biased into seating engagement in a pair of opposed spot welding tips transmit and receive ultrasonic waves and associated circuitry measures the time of flight between the transducers which is a function of tip separation, workpiece temperature and nugget size which are indicators of the progress of a weld. The rate of change of flight time is measured and the weld current is adjusted early in the weld cycle to maintain a preset rate of weld growth. The weld current is terminated later in the cycle if the transit time rate falls below another preset value. Otherwise the weld current and termination time follow a standard schedule.

Ultrasonic welding wire termination apparatus

Abstract: Apparatus for ultrasonically welding a wire to a wire terminal. A stationary anvil forms the lower horizontal wall of a work chamber into which a wire workpiece is inserted. The vertical walls of the work channel are formed by the walls of a slot in a relatively movable horizontal support plate cantilevered from a base. The slot in the support plate fits about the anvil. The horizontal support plate is oscillatable to swing vertically thereby adjusting the size of the work channel. A terminal is seated on the support plate and covers the chamber. An ultrasonic welding tip contacts the terminal and forces down the support plate so as to maintain very tight spot contact between the wire on the anvil and the terminal, against the flexure of the cantilevered arm. Welding of the wire to the terminal is effected by the ultrasonic vibration of the welding tip against the terminal. As the wire is tightly confined in the work channel, no spreading or splaying will occur while the wire is in a plastic-like state, and the spot weld precisely locates the wire end on the terminal.

Spot welding technique

Abstract: A beam (18) from a single laser source (16) is divided into a plurality of beams (24,30). Each beam (24,30) is directed into one end of a different lightguide fiber (36,38) having equal lengths so as to pass therethrough. The opposite ends of the fibers (36,38) are located proximate inner and outer sleeves (12 and 14) which are simultaneously spot welded at a plurality of sites by the beams exiting the fibers.

Male spot welding electrode

Abstract: A male spot welding electrode includes a weld end portion having a generally flat contact surface and a tapered mounting portion containing an inlet bore. The inlet bore communicates with an internal cavity, containing cooling fins, for coolant fluid flow. The diameter of the internal cavity is made larger than the diameter of the inlet bore in order to maximize the cooling surface for the dissipation of heat generated during repeated welding operations. The male spot welding electrode is produced from a single billet of copper material through a process of back-extrusion and swaging.

Cinematography of Resistance Spot Welding of Galvanized Steel Sheet Preweld and postweld current modification have a significant effect on nugget quality

Abstract: The effects of preheat, post­ heat, upslope, and downslope current modifications on the resistance spot welding of galvanized steel sheet are analyzed using high-speed cinematogra­ phy. Correlations between the timing of the current modification and the observed physical phenomena through­ out the weld process are discussed. In addition, the duration of current modifi­ cation compared to the total weld time is examined in terms of relative effective­ ness for improving weldability. The melting sequence of the zinc coat­ ing at the electrode and faying interfaces was found to vary with the type of current modification used. A mechanical seal of deformed iron was found to help constrain the molten material between the electrode tips, even when peripheral melting occurred. The correlation found between the motion of the molten nug­ get and the pulsing of the current is described. In addition, it is shown that preweld current modification led to slow­ er, more uniform weld nugget formation, which in turn should lead to improved weldability.

Method and apparatus for the non-destructive checking of spotwelds between metal sheets,produced by electric welding

Abstract: A electrical current of predetermined strength is passed through a spot weld by a first pair of electrodes. The electrical potential difference between two points, respectively upstream and downstream of the spot weld along the current path, is measured with a second pair of electrodes. In particular, this second pair of electrodes is used to carry out at least one first measurement before the application of the current, and at least one second measurement during the application of the current. These measurements are carried out at two instants separated by a time interval equal to or a whole multiple of the period of the main power voltage. The difference between the values measured in the first and second measurements provides an indication of the quality of the spot weld.

Head supporting body for magnetic disk

Abstract: PURPOSE: To realize the head supporting body for a magnetic disk having such high reliability as no gimbal part being subjected to buckling deformation by providing a plate like elastic part along airstream in terms of cantilever between the holding part to a load arm tip of the gimbal part and a slider supporting part. CONSTITUTION: A gimbal part 3 has a plate-like elastic part 21' between the holding part 12 at the rear end side fixed by spot welding 11 to the tip of a load arm 4 and the supporting part 13 at the tip side supporting a slider 2 by fixing it and this outer edge part 21 is made cantilever towards the airstream outlet side from the airstream inlet side along the airstream. When friction force is exerted on the slider 2, tensile force is exerted on the elastic part 21' of the root of the outer edge part 21, but no territory on which compression force exerts exists, hence no permanent strain due to the buckling deformation of the gimbal part 3 is generated. COPYRIGHT: (C)1988,JPO&Japio

Spot welding electrode apparatus

Abstract: A spot welding electrode valve includes a body having an upper and a lower tapered portion and containing a hollow valve which houses a spring loaded sensor having a valve portion. The spot welding electrode valve is adapted to be mounted to a standard resistance welding electrode through its upper tapered end portion and in the mounted position the valves in the body are closed so as to circulate coolant fluid through the body and the welding electrode. The lower tapered end portion is adapted to receive a welding cap or tip which when mounted actuates the sensor to open the valves in the body to allow coolant fluid to flow inside the welding cap or tip and to remove heat generated in the welding process. When the welding cap or tip is removed for replacement or repair, the sensor will automatically close the valves in the body and confine circulation of the coolant fluid inside the spot welding electrode valve and welding electrode without external release. One purpose of the spot welding electrode valve is to allow replacement of welding caps or tips, particularly with regard to multi-electrode resistance welding machines, without the need to close the main coolant flow valve of the system.

Casing for air cooled electric machines

Abstract: The casing of an electric machine has ribs welded onto a casing jacket, the ribs displaying a U-shaped profile. The legs of the ribs can be secured by resistance projection welding to the casing jacket. One rib can be somewhat larger than the other ribs and used as a support for a foot.

Dispersion hardened copper alloys and production process therefore

Abstract: A process for producing a dispersion hardened copper alloy includes admixing to a copper melt from 0.3 to 15 weight % of molybdenum to provide a mixture which is a melt; superheating the mixture to a temperature ranging from about 200° C. to about 1000° C. above the melting point of coper to provide a superheated melt; and subjecting the superheated melt to very rapid solidification at a cooling rate ranging from 104° to 106° C./sec. The above process produces dipsersion hardened copper alloy comprising copper and from 1 to 15 weight % of molybdenum which is present in the dispersion hardened copper alloy as particles having a diameter of less than 0.1 μm embedded in the copper matrix. Such dispersion hardened copper alloys are useful for providing electrical conductors which are subjected to elevated temperatures, such as for providing spot welding electrodes, particularly for welding of zinc-galvanized sheet metal. Such alloys do not become brittle when heated up to around about 500° C. or even up to around about 800° C.

Spot welding gun

Abstract: PURPOSE:To cope with a direct welding and indirect welding by one unit of a gun by constituting to connect a pair of electrodes to a pair of output terminals of a transformer and to connect auxiliary electrode to either one part of the output terminals. CONSTITUTION:The electrodes 11, 16 at the tip of each arm 10, 15 are connected to the output terminals 14, 18 of a transformer 13 via cables 12, 17 and an auxiliary electrode 19 is connected to one part of the terminal 18 via a cable 20. A spot welding is made under a current circuit E1 with the electrification by making the electrode 19 in non-contact state by pinching with pressure the flange part F of panels W1, W2 between the electrode 11, 16. The spot welding is made under a current circuit E2 with the electrification by making the electrode 19 in press-fitting state to the panel W2 by pinching with pressure the flange part F between the electrodes 11, 16 together with an insulating type pack electrode 21. Accordingly both direct welding and indirect welding can be coped with one unit of the gun.

Spot welding machine

Abstract: PURPOSE:To prevent the reverse charging of an electrolytic capacitor and to prevent the deterioration of the performance of the electrolytic capacitor by incorporating two pieces of electrolytic capacitors, two pieces of gate turnoff thyristors and resistor with the specified circuit into the power source circuit of a capacitor type spot welding machine CONSTITUTION:The charging and discharging circuit for capacitor equipping a thyristor switch 2 is formed between the DC power source 5 of a capacitor type spot welding machine and the primary line of the transformer for welding The electrolytic capacitor 1a, 1b in the same capacity is connected in parallel by reversing the polarity via a charging resistance 6 to the DC power source 5 and the connection point at the cathode side of both capacitors is linked with the connection point of two pieces of gate turnoff thyristor 7a, 7b and connected to the negative pole side of the DC power source 5 via a resistance 8 and the thyristor 2 is connected to the primary side of a welding transformer 3 as well Since both electrolytic capacitors 1a, 1b are not charged reversely in case of spot welding the body 4 to be welded, the performance of the capacitor is not deteriorated by the reverse charging and its use for long term is enabled

Spot welding device

Abstract: A spot welding device for welding car bodies at a plurality of different positions without the need to move the car body to the welding device for each weld position. The device comprises a polyhedron shaped rotating member having a plurality of electrodes disposed on surfaces of the rotating member. The member is rotated to select a desired surface and the configuration of electrodes thereon to thereby perform a plurality of welds with the electrodes on the selected surface.

Manufacture of alloying hot dip galvanized steel sheet excellent in spot weldability

Abstract: PURPOSE: To manufacture the titled steel sheet excellent in spot weldability, by applying oxide film formation treatment composed principally of ZnO to an alloying hot dip galvanized steel sheet in which a plating layer is specified. CONSTITUTION: A hot dip galvanized steel sheet is subjected to alloying treatment at a temp. as high as about 450W800°C for a short time (≤about 10sec) so that an alloy layer of ≤3μ crystalline grains comprises 80% of a plating layer surface. This alloying hot dip galvanized steel sheet is used as a starting sheet, and an oxide film composed principally of ZnO is formed on the surface of the above sheet by about 30W500mg/m 2 per one side. By this method, the alloying hot dip galvanized steel sheet excellent in spot weldability is obtained, and, by using this sheet, the number of continuous spot welding is increased in spot welding and welding can be continued for a longer period without changing a tip, so that durability of tip can be improved. COPYRIGHT: (C)1988,JPO&Japio

Heat control for electric resistance welding in steel pipe production

Abstract: A heat control system for electric resistance welding (ERW) for use in pipe manufacturing has been developed. The distinguishing features of the control system are: (1) use of a silicon photodiode array as a heat input sensor, (2) feedback control for steady welding, and (3) open-loop control for transient welding. This control system has been introduced into three ERW mills at Keihin Works, Nippon Kokan Kabushiki Kaisha, and shows excellent performance in production.

Tack welding method for steel sheet

Abstract: PURPOSE:To prevent the camber of steel sheet with the pressure of a spot welding and to cause no defective adhering by spot-welding the peripheral part of the welding zone of a laminated steel sheet by press-pinching it with a press-pinching device simultaneously with welding the press-pinching part. CONSTITUTION:Steel sheets 12, 14 are laminated by coating an adhesive 10 on one side hereof and the peripheral part of the tack welding zone 11 thereof is subjected to a spot welding with its press-pinching by pressure devices 15, 19. The camber of the steel sheets 12, 14 by the pressure of the spot welding can thus be prevented and they become in a adhesive state with the hardening of the peripheral adhesive 10 of heat hardening type by the heat of the spot welding as well and the press-pinched steel sheets 12, 14 is adhered by the adhesive 10. Due to the peripheral part of the welding zone 11 being adhered simultaneously at tack welding time no adhering defect is caused in case of adhering the steel sheets 12, 14 by a hot press at after stage.

Electrode for spot welding

Abstract: PURPOSE:To prolong the service life of an electrode for spot welding by using Cu containing specific amounts of Al and other elements as an electrode for the spot welding of a galvanized sheet. CONSTITUTION:As an electrode material for the spot welding of a galvanized sheet, Cu containing, by weight, 0.2-3% Al and 0.5-1.5% Cr or further containing 0.03-0.2% Zr and 0.1-1.0% Ag is used. By this method, an Al2O3 film is formed by means of heat at the time of welding on the surface of an electrode composed principally of Cu and, as a result, the reaction of Cu in the electrode material with Zn in the galvanized sheet is prevented and the consumption of Cu due to reaction with Zn is prevented, by which the service life of the electrode can be prolonged. Further, Cr and Zr improve the hardness of the electrode at high temp. and Ag prevents the occurrence of sparks at the time of welding, and all of which contribute to the prolongation of the service life of the electrode.

Method and apparatus for preliminarily tacking structural components to each other

Abstract: Structural components, for example rotor components for a flow-dynamic engine, are first tacked to each other prior to final joining. The tacking is accomplished by a spot resistance welding or a high energy ray welding using a small welding material ball at each welding spot or location. The balls are supplied to a welding spot through a hollow, evacuated electrode of the resistance welding apparatus.

Spot welding machine

Abstract: PURPOSE:To shorten the electrifying time and to save the consuming electric power by feeding a welding current by pressing a fixed pressure and by impressing an impact pressure to the electrode at the timing melted to certain degree. CONSTITUTION:A fixed pressure is impressed on electrodes 2, 4 via a pressure cylinder 14 with the first switch 18 being closed by a start signal ST. On the other hand, a welding current I is fed to the electrodes 2, 4 with the welding delay time control part 44 starting the count of a synchronours pulse SP and closing the second switch 42 at the time of counting three pieces. An impact pressure delay time control part 52 impresses the impact pressure by closing the third switch 48 at the time of counting six pieces. The joining is therefore promoted, the welding time is reduced and the power consumption can be saved because of the impact being applied at the timing of the welding zone being melted to some degrees.

Ultrasonic Wire Bonding Using a Complex Vibration Welding Tip

Abstract: Ultrasonic wire bonding using a complex vibration welding tip is proposed and studied to improve welding characteristics of ultrasonic wire bonding of thin various metal wires. The welding system designed consists of a complex transverse vibration rod driven by a 40 kHz and a 60 kHz ultrasonic longitudinal vibration systems. These vibration systems are driven simultaneously by independent vibration controllers and amplifiers. Welding specimens used are 0.05 mm to 0.15 mm diameter aluminum wires and 1.0 mm thick copper plates. These welding specimens are welded successfully by the complex vibration welding equipment. And also, using this method, the weld strength of wire bonding becomes independent to the direction difference between welding tip vibration and wire length.

Spot welding electrode and method for making it

Abstract: The electrode comprises an electrically conductive body including, at least at its active portion, a sintered layer of silver powder having a particle size from 1 to 10 microns and crystalline graphite

Constant current control method in spot welding machine

Abstract: PURPOSE:To pertinently set the current in starting without performing a trial electrification, etc. by fixing the approximate value of the maximum current and power factor angle of a welding machine and by performing the initial electrification at the firing angle which is decided from a thyristor firing angle - relative welding current characteristics. CONSTITUTION:Since the power factor angle of a spot welding machine is generally 50-70 deg. it is given at 60 deg. as the approximate value and the approxi mate value of the maximum current is decided by the shape of the welding machine. For instance, in case of selecting 8KA for the approximate value the relative current to the set current value makes 0.5, so the corresponding firing angle makes about 105 deg. from the thyristor ignition angle - relative welding current characteristics relation chart. And the initial welding cycle electrification is performed at this ignition angle and after the 2nd cycle and on the ignition angle is controlled so as to eliminate the error in the welding current measuring value and set current. Consequently, the current at the starting time can be made optimum without performing a pilot electrification, etc.

Spot welding method for expand metal

Abstract: PURPOSE:To normally form the nugget in spot welding and to increase a welding strength by welding to the welding object the place to be welded after forming it in a plate shape with its pressing in advance. CONSTITUTION:The projection like part of the place 1a to be spot-welded of the expand metal 1 having numerous uneven projection like parts is subjected to pressing in a plate shape in advance by a pressing means. The area of this pressing plate like part 1a is made somewhat larger than the area of the electrode 3, 4 of a spot welding machine. The spot welding is performed after abutting to a metal plate 2 the expand metal 1 which formed the plate part 1a. In this way the strength of the weld zone can be increased.

Spot welding machine

Abstract: PURPOSE:To enable the execution of the removal of foreign matters on a welding surface simply and surely by providing the air passage that a gaseous body discharging port opens in the welding tip direction close to a shank and by constituting that no gas discharging port comes in contact with a work in welding. CONSTITUTION:A spot welding gun 1 is made to fit the tip 4 for welding via a shank 5 to the tip of each arm 2 driven by air cylinder 7 and to connect pressure air feeding pipes 11a, 11b to an air source 13 via a pressure valve 8. Each tip of a branch pipe 11c is approached to the shank 5 and opened toward the tip 4 direction by providing the quick exhaust 12 composed of a valve mechanism on the pipe 11a. And the tip of the pipe 11c is made not to interfere with a work even in case of the work being composed of a curved surface. The foreign matter removal on the welding surface can thus be enabled simply and surely.

Ac storage mixed gantry breakeven welder

Abstract: The utility model provides a novel spot welding machine for the elevator manufacturing, which can weld general steel plates, organic coating steel plates, and stainless steel plates in a non-injury way The spot welding machine is characterized in that a capacitance energy-storing power supply and an industrial frequency AC power supply are adopted by the same spot welding machine; also, the problem of the DC magnetization in the AC energy storage composite design is solved; meanwhile, the spot welding machine can make a direct welding as well as an indirect spot welding A suspended type electrode can make the spot welding to weldments at optional positions at the range of 2400*1200 in plane dimension; therefore, the adjustment of appropriate switches is just needed, the parts processed by the materials can be welded in the non-injury way