Abstract: Systems and methods for determining welding parameters using material thickness and wire diameter are disclosed. An example welding-type system includes a power source; an input device configured to receive a first user input specifying a thickness of a material to be welded; and control circuitry configured to: determine a plurality of welding parameters based on the first user input and based on a user-specified wire diameter; control the power source based on one or more of the welding parameters; and control a wire feeder based on one or more of the welding parameters.

Abstract: This seam-welding device carries out seam welding while repeating one cycle comprising a melting period, an interruption period, and a heating period implemented either before or after the interruption period. A welding current is applied between a pair of roller electrodes so as to form a welded part between workpieces during the melting period, the application of the current between the roller electrode pair is interrupted so as to solidify the welded part during the interruption period, and a heating current smaller than the welding current is applied between the roller electrode pair so as to heat the laminated body within a solidification temperature range of the welded part during the heating period. Consequently, even when the welding speed is increased, formation of cracks and spatter is effectively suppressed such that a high-quality joined product is obtained.

Abstract: A spot welding method joins metal sheets by: clamping a stacked section of two or more stacked metal sheets with a pair of electrodes at a load of 100 N or more; applying pressure around the electrodes at a load, which is 5-1000% of the load due to the pair of electrodes, using a pressurizing member, which applies pressure on the stacked section in regions that are 20% or more of the total outer circumference of the electrode tips and for which the continuous regions of the entire outer circumference of the electrode tips that are not pressed are 30% or less (including 0%) of the entire outer circumference of the electrode tips; and passing welding current from the electrodes to the stacked section.

Abstract: A seam welding apparatus and a seam welding method perform a seaming process on workpieces of various shapes having flange sections, by preventing a welding track formed by upper and lower rotary electrodes from becoming displaced from a welding reference line established on the flange section. The seam welding apparatus includes two rotary electrodes for gripping the flange section therebetween while seam-welding the flange section, a support for synchronizing movements of the two rotary electrodes with each other in a widthwise direction of the flange section, a turning mechanism for pressing at least one of the two rotary electrodes toward the workpiece body, a roller that abuts against an end face of the flange section, and roller adjusting means for positionally adjusting the roller.

Abstract: A phase controlled weld controller system provides a stable timebase phase reference which has improved transient response in the presence of spurious noise generated by other external equipment coupled to the same voltage source. The system estimates a phase error between an internal phase reference generator and the voltage source. The system also estimates the phase distortion generated by the weld control when operating with an inductive impedance load when significant line impedance is present. The weld controller provides compensation for the phase distortion in the timebase phase reference using the estimated line impedance to realize a phase reference which more accurately tracks the voltage source.

Abstract: A weld control system, supplied by a polyphase voltage source, consists of an isolation contactor supplying power to separate single phase weld controllers. The single phase weld control systems have their separate power modules combined into a single power module assembly for more efficient cooling and electrical interfacing. The single power module consists of a semiconductor switch for each phase of the polyphase voltage source and a single chiller plate for mounting and cooling the switches. The chiller plate functions as a heat sink and is machined to create a series of channels that become coupled together to form a continuous tube having a single input and a single output for a coolant liquid. A SCR pair, housed in a single package in a back-to-back configuration having an isolated base construction. The base has good thermal conductivity between the heat generating semiconductors in the package and the base.

Abstract: A weld control system, supplied by a polyphase voltage source, consists of multiple and separate single phase weld controllers. The single phase weld control systems have their separate power modules combined into a single power module assembly for more efficient cooling and electrical interfacing. The single power module consists of a semiconductor switch for each phase of the polyphase voltage source and a single chiller plate for mounting and cooling the switches. The chiller plate functions as a heat sink and is machined to create a series of channels that become coupled together to form a continuous tube having a single input and a single output for a coolant liquid. A SCR pair, housed in a single package in a back-to-back configuration having an isolated base construction. The base has good thermal conductivity between the heat generating semiconductors in the package and the base.

Abstract: A thyristor voltage detector includes a current-limiting resistor having a high resistance (e.g., 30 kilo-ohm) and a switching device (e.g., photo MOS FET) of a switching photo coupler which are serially connected between a thyristor and a waveform converter (e.g., a pair of photo couplers). The photo MOS FET is turned on by a light from a light emitting diode of the switching photo coupler in respect to a high level of a switching control signal. A voltage across the thyristor is applied to the waveform converter via the photo MOS FET and the resistor. The arrangement eliminates the need for a step-down transformer, achieves downsizing and cost cutting, and reduces electric power consumption.

Abstract: A single resonant DC charging circuit provides both the power and timing for the pedestal insertion is, likewise, controlled by a single trigger circuit input and by a saturable reactor which controls the firing of a thyratron switch.

Abstract: A resistance welding control system is disclosed which comprises a resistance detection unit for detecting an interelectrode resistance by measuring welding current and voltage applied between electrodes; a compensation section for comparing a resistance value as detected with a predetermined model resistance value and determining an amount of compensation of the welding current in accordance with the difference therebetween; and a current control section for controlling the welding current on the basis of the amount of compensation of the compensation section.

Abstract: A rack mountable weld controller for use as a plug in card within a rack of a programmable logical controller (PLC) system. All signals between the PLC and the weld controller are through the backplane of the rack in which the weld controller is installed. In this manner, the large number of signals which are needed to operate the weld controller may be passed through the backplane rather than over a set of cables connecting the weld controller to an input card and output card which are themselves plugged into a backplane slot.

Abstract: A method is disclosed for controlling the magnitude of current delivered through welding electrodes to a workpiece to be welded using resistance welding techniques, in order to prevent weld expulsion and concomitant diminishment of weld quality. Weld expulsion is detected by determining changes in resistance during formation of the weld, by periodically determining the power factor, and the primary circuit of the welding transformer. The power factor is determined by determining the relative timing between the commencement of the applied voltage, the zero crossover point of the applied voltage, and the ensuing zero point of the applied current.

Abstract: A welding system controller for controlling the welding of a workpiece including a switch for selectively applying power to a welding transformer and a controller for controlling the power delivered to the welding transformer by the switch to set the power level of the welding transformer. The controller allows the operator to set the time to reach the set power level, the time the set power level is maintained, and the time to decrease the power level from the set power level to zero.

Abstract: Structure for and method of controlling the firing point of thyristors in a phase controlled contactor in a resistance welding circuit in accordance with variations in current line voltage and/or one of resistance and inductive impedance in the welding circuit including structure for and the method of determining the firing point in a cycle of alternating electrical energy fed to the welder in terms of its distance from zero voltage cross over point and determining the current lag after a subsequent zero voltage cross over point of the voltage signal, determining the power factor of the welding circuit from these angular measurements and selecting a new firing delay for the contactor in accordance with the circuit power factor and the percent heat selected in the welding circuit, and subsequently correcting the firing delay in accordance with the percent heat selected in view of changes in the line voltage and circuit current.

Abstract: A method and arrangement are described for regulating the welding operation in a resistance welding machine by sensing the welding current and controlling the welding time. A first integrator (20) determines the desired total energy to be supplied to a welding spot from a desired welding current preset by means of a function generator (18) and a preset welding time. An integrating device (25) connected to the welding-current sensor (14) determines the actual energy supplied. A comparator (24) compares the desired total energy with the actual energy in order to switch off the welding current by means of a start/stop module (30) in the event of equality between desired value and actual value. In this manner, fluctuations in the supply voltage are compensated by lengthening or shortening the time during which energy is supplied to the welding spot in order to ensure the quality of the welding from one welding spot to another.

Abstract: A resistance-type welder employing a three phase, pulsed power supply and a pair of opposed electrodes which a workpiece may be clamped under pressure, includes a microcomputer based control system for allowing precise selection and control of welding sequences such as the duration during which the workpiece is clamped, the duration during which current is supplied to the electrodes and the duration during which the workpiece remains clamped between the electrodes after current flow is terminated. A plurality of switchable input devices allows data corresponding to a plurality of process variables to be input to a random access memory. A central processor enabled by a manually operable control switch produces control signals for operating a control and firing circuit in accordance with programmed instructions and the data stored in the random access memory in order to control each step in a welding cycle for precise time periods.

Abstract: In electrical resistance welding apparatus comprising two welding electrodes connected through respective supply cables to an electrical power supply which can generate welding current with selectively-variable effective values, a control device is provided which, in use of the apparatus, measures the resistance between the electrodes clamped on the pieces which are being welded and the resistance between the ends of the supply cables. During welding, the device detects the change in the resistance between the electrodes with time and, on the basis of a linear combination of several parameters of the resistance curve detected, establishes whether the spot weld effected should be considered acceptable or unacceptable. In the latter case, the control device causes the welding operation to be continued with a current having a higher, rms value so as to correct the spot weld made.

Abstract: Items constituting a resistance welding schedule are set to desired numerical values by pressing three kinds of keys, namely a shift key for designating one item after another, and increment and decrement keys for setting or changing a numerical value corresponding to each designated item. Each item is displayed in an individual display section of a display unit, with the display sections being made to blink sequentially as each corresponding item is designated. The numerical values are displayed directly item by item and are set sequentially as the respective items of the schedule are designated.

Abstract: A power supply for a pulse type electrical resistance welder includes an A.C. source of electrical power, a firing circuit for delivering spikes of current to a pair of welding electrodes and a precharging circuit for precharging the firing circuit with a quantity of electrical energy sufficient to produce satisfactory welds in the first cycle or first few cycles of power. The precharging circuit is controlled by control circuit which includes a thumb wheel switch for presetting the voltage to which the firing circuit is to be precharged. A relay circuit automatically disconnects the precharging circuit from the firing circuit before the latter discharges its energy to the welding electrodes. A safety circuit is provided for automatically discharging the firing circuit in the event of a power failure.

Abstract: An improvement in a method of welding the shanks of successive nails to a pair of wires to form a series of wire connected nails suitable for packaging and use in a power driven fastener driving device which includes the steps of connecting a pair of electrodes with a source of electrical current characterized by repetitive cycles and effecting repetitive nail-to-wire cycles each of which includes an initial movement of (1) the shank of an unattached nail (2) a pair of wires extending transversely thereacross and (3) the electrodes from a position of initial contact into a welding station wherein pressurized contact between the electrodes, the nail shank and the wires is maintained and a final movement out of the welding station to a final release position of the electrodes with respect to the welded together nail shank and wires.

Abstract: A computer-controlled welding apparatus includes a phase-controlled resistance welding circuit (A) for selectively conducting pulses of a welding current to a workpiece (B) and a control circuit (C) for controlling the conduction of the welding current. The control circuit includes a line clock generator (30) for determining the beginning of each voltage half line cycle and a conduction sensor (34) for determining whether or not a contactor (14) is conducting current to the workpiece. A microcomputer (40) is preprogrammed with a plurality of power factor correction curves, each of which represents weld current vs. firing angle for a fixed hangover angle. The computer is programmed to select one of the power factor correction curves. If the preceding half line cycle was conductive, the program selects the curve which corresponds to the hangover angle of the preceding half line cycle.

Abstract: An apparatus for controlling and programming welding guns, constituted by a set of electronic component circuit boards enclosed in a casing provided with a keyboard and a programming and control display unit which are connected electrically together so as to enable various functions to be performed on the static switches of the welding gun to which the apparatus is connected, namely: a first so-called basic function, i.e.

Abstract: A method for controlling a welding current in a resistance welder which phase-controls an A.C. power supply voltage by a thyristor to control the welding current to a target value. Prior to supplying the welding current, a test current is supplied to measure a power-factor angle of a load. A plurality of curves representing relations between the welding currents and control voltages to a phase-shift pulse generator for a plurality of power-factor angles of the load are presets and one of the curves is selected in accordance with the selected power-factor angle of the load. A variation of the A.C. power supply voltage is measured. A period of a pulse generated by the phase-shift pulse generator is controlled based on a value determined in accordance with the selected curve and the measured variation of the A.C. power supply voltage to control a firing angle of the thyristor.

Abstract: A monitoring and control system for a resistance welding apparatus. The system monitors the quality of a weld as a weld is formed and terminates the welding current when a quality weld is completed. The monitoring function is performed by detecting a change in the instant welding current is extinguished at the end of half cycles of welding current in the secondary winding circuit of the welding transformer. The weld current is terminated when a detected charge in the instant current is extinguished relative to a reference equals a preprogrammed value which is indicative of an acceptable quality weld between welded parts.

Abstract: A control system for resistance welders of the type in which welding current is supplied to a workpiece through a transformer. The system assures weld quality by monitoring the change in resistance across the weld during the welding operation without the need for auxillary leads or separate sensing transducers at or near the workpiece and automatically terminates the welding current when a quality weld is made as determined by resistivity characteristics of the weld. The system monitors discrete changes in the characteristics of the current in the primary of the welding transformer which occur as a result of changes in weld resistance. The system compares the monitored current characteristics of the welding current with a plurality of parameters indicative of a quality weld and terminates the welding current when a selected number of monitored characteristics are within selected parameters.

Abstract: A control system for resistance welders of the type in which welding current is supplied to a workpiece through a transformer. The system assures weld quality by monitoring the change in resistance across the weld during the welding operation without the need for auxillary leads or separate sensing transducers at or near the workpiece and automatically terminates the welding current when a quality weld is made as determined by weld resistivity characteristics. The system monitors discrete changes in the characteristics of the current in the welding transformer which occur as a result of changes in weld resistance.

Abstract: A resistance-type welder employing a pulsed power supply and a pair of opposed electrodes between which a workpiece may be clamped under pressure, includes a microcomputer based control system for allowing precise selection and control of welding sequences such as the duration during which the workpiece is clamped, the duration during which current is supplied to the electrodes and the duration during which the workpiece remains clamped between the electrodes after current flow is terminated. A plurality of switchable input devices allows data corresponding to a plurality of process variables to be input to a random access memory. A central processor enabled by a manually operable control switch produces control signals for operating a control and firing circuit in accordance with programmed instructions and the data stored in the random access memory in order to control each step in a welding cycle for precise time periods.

Abstract: A precision key pad controlled controller for a resistance welding machine is provided which may be set to deliver welding power to each of a multiplicity of welding operations on a precisely controlled repeatable basis. The controller incorporates circuitry for assuring that an accurately controlled amount of power is delivered for each welding operation by providing precise phase angle control despite variations in line voltage and line disturbances. The controller is constructed to incorporate selected numbers of steps to be performed automatically in sequence by the controlled welding machine in carrying out a particular welding operation. The duration of each step of the welding machine, the amount of welding power to be delivered, and other parameters are set for each particular welding operation by the key pad, and displayed on an associated alphanumeric display.

Abstract: A method and system for controlling resistance welding whereby the preferred quality of resistance welding can be ensured automatically during the welding process by controlling the electrode pressure so that the electrode resistance changes in accordance with a reference resistance curve, or by additionally controlling the electrode voltage so that the electrode voltage changes in accordance with a reference voltage curve. The system according to the present invention comprises an electrode voltage sensor, an electrode current sensor, a reference resistance generator, a reference voltage generator, a differential amplifier, a pressure control device, a current controller and so on.

Abstract: A resistance welder is provided having an electronic contactor, a welding transformer coupled in series with the electronic contactor, and a secondary circuit with a welding load connected to the welding transformer. The series circuit of the electronic contactor and the welding transformer is adapted for receiving power from an AC power source. The resistance welder also includes a control device having a voltage detector coupled to detect a voltage across the electronic contactor for producing a first signal according to the detected voltage, a delay circuit coupled to receive a primary voltage across the welding transformer for delaying the primary voltage by a value determined by a first time constant thereof to produce a voltage signal, a switch coupled to receive the first signal for resetting the delay circuit according to the first signal, and a gain control circuit coupled to receive the voltage signal for controlling a transmission gain of the voltage signal to produce a gain controlled signal.

Abstract: A system for resistance welding in which the welding voltage between the electrodes is controlled by changing the pressure applied to the electrodes or the firing phase angle of the welding current in accordance with a reference voltage curve or a reference voltage integration curve. The system comprises a voltage sensor, a reference voltage generator, a differential amplifier, and a pressure control device, or a calculating unit for determining an appropriate firing phase angle of the welding current. The system thus improved can ensure a stable, good welding quality, since the welding voltage is always controlled by a series of optimum welding voltages, during the welding process, in accordance with a reference voltage curve with respect to time, preferably in terms of cycles of the welding current.

Abstract: A power supply apparatus for a resistance welder has an inverse-parallel thyristor circuit for constrolling the welding current. One of thyristors connected in inverse-parallel relationship is turned on by a first signal whose reference phase is established by a synchronizing signal which is based on a voltage wave form of an AC power source and the other thyristor is turned on by a second signal whose reference phase is established by a signal which is delayed half a period of the voltage wave form with respect to the first signal, so that integrals of positive and negative halves of the output voltage wave form of the inverse parallel thyristor circuit can always be made equal.

Abstract: A precision resistance welding machine controller is provided which may be set to deliver welding power to each of a multiplicity of welding operations on a precisely controlled repeatable basis. The controller of the invention is modular in nature and is microprocessor controlled. The controller includes a master control module which is standard for all models, and the master control module incorporates certain control circuits including a circuit for assuring that an accurately controlled amount of power is delivered for each welding operation. This is achieved by providing precise phase angle control despite variations in line voltage, and line noise disturbances. The controller also includes a personality module which is constructed for a particular welding operation, and which is programmed to incorporate any selected number of steps to be performed in sequence by the welding machine controlled thereby in carrying out the particular welding operation.

Abstract: A power factor monitoring and control system with line disturbance immunity for controlling the quality of spot welds made by resistance welding techniques such as those used in the automotive industry on assembly line welders. As is commonly known, quality and strength of a spot weld can be correlated to a change in resistance measured through the weld as the weld progresses during the fusion progress. This change in resistance in the secondary circuit reflects back through the transformer to its primary circuit as a change in power factor. The timing changes resulting from the change in power factor are sensed by the control circuitry of this system to generate signals which are used by an 8-bit microprocessor properly programmed to operate on the signal information. By determining the amount of increase or decrease that has occurred in the current conduction angle during a group of welds, a basis for the control of the welding heat is obtained.

Abstract: An automatic voltage compensation control for a microprocessor controlled resistance welder system includes a digital voltmeter for measuring the line voltage cycle by cycle and associated circuitry to compensate the welding current in response to the measured line voltage in a manner which tends to hold the welding current constant and independent of line voltage variations. The digital voltmeter consists of a voltage-to-frequency converter coupled to a counter. The output of the voltage-to-frequency converter which is proportional to the line voltage is accumulated for the period of one cycle of the line frequency. This produces in the counter at the end of each measurement interval, a number of counts proportional to the average line voltage. The microprocessor using the count obtained adjusts the welding current by altering the timing of the firing points of the SCR contactors used to control the welding current.

Abstract: A control circuit for accurately controlling the duration of a welding operation.

Abstract: A phase controlled regulating circuit for a portable spot welder having an output transformer, utilizes a normally saturated transistor across one diagonal of a diode bridge circuit to interrupt the connection between the control voltage source and the regulating source, in response to a timer input.

Abstract: A high speed seam welding system wherein single phase alternating current welding pulses are applied to electrode mechanism during only a less than maximum amplitude fractional portion of the wave form representing each successive current half cycle, and the current is substantially cut off between current applications to permit cooling. The relative seam welding movement of the electrode mechanism and the material to be seam welded is coordinated with the duration of the welding and cooling periods to more rapidly form a line of uniform weld nuggets. The system may also be operated at more conventional welding speeds to weld relatively heavy gauge materials.

Abstract: A circuit for improved control of current for use in conjunction with an inductive load, for example, a transformer in a welding operation. The circuit of this invention is adapted to maintain the percentage of total RMS current demand directly proportional to a reference signal. A nonlinear control signal generator is provided to supply a control signal which is compared to the reference signal to operate a switch means for controlling the flow of current in the inductive load.