Abstract: A method and apparatus is disclosed for forming a ball at the end of bonding wire or lead wire held in a capillary wire holding and bonding tool for ball bonding of the lead wire to an integrated circuit chip. The method of ball formation is of the type in which the end of the bonding wire is enclosed in a shroud or shield and the shield and the end of the bonding wire are flooded with an inert cover gas. Ball formation is accomplished by electrically discharging an arc between the bonding wire and the shroud for melting and forming the ball at the end of the wire. A passageway is provided for delivering and mixing hydrogen gas into the inert cover gas delivery line at a location upstream from the shroud sufficient for complete mixing. The rate of flow of hydrogen gas is metered and controlled for adjusting the percent by volume of hydrogen in the cover gas mixture to a desired range.

Abstract: A multi-purpose welding power supply to provide different modes of welding from a single unit. Two positive output terminals are provided, one for low amperage welding up to about 300 amp which includes an inductor and slope resistor and one for high amperage output up to about 600 amp which bypasses the inductor and slope resistor in the low amperage circuit. A pulsing circuit is provided to impose on the 300 amp output either 60 pps or 120 pps pulses on a standard direct current background. A variable pulse width control circuit is integrated with the pulsing circuit to vary the pulse width. A "hot start" feature is included with the 60 pps welding mode to provide 120 pps pulses for an initial pre-selected time period.

Abstract: An instrumented spot welding electrode significantly improves the weld quality available from production resistance spot welding machines by providing real time measurements of key multivariable resistance welding parameters. The real time data provided may be used as inputs to adaptively control welding machines and dynamically adjust welding system operation responsive to the sensed variables. A number of sensors are positioned within a cavity specially formed into a water cooled electrode tip to obtain the desired measurements while being protected against physical damage. The sensors are advantageously placed in good thermal and electrical contact with a plug element which bears directly on the workpieces being welded to enhance the accuracy of the sensed variables. This specially configured and instrumented sensor cavity is ideally suited for use with all end types of electrodes including spherical, truncated, offset, flat and the like.

Abstract: The user of electric arc welding equipment is provided with audible feedback signals which provide useful information relating to the output current and voltage of the welder. An audio tone is generated and is frequency modulated by a signal which corresponds to welder output voltage. The tone is amplitude modulated by a signal corresponding to output current thus providing the user with a synthesized feedback signal having a voltage-proportional pitch and current-proportional volume. Additional modulation means are disclosed for introducing a current-proportional warble component to said tone.

Abstract: Disclosed are welding current pick-ups which are switched into welding circuits. Outputs of these pick-ups are connected to inputs of a logical coincidence unit having its output connected to a control input of a welding program control unit whose output is connected with a drive adapted for moving the workpieces being welded.

Abstract: A power source includes first and second control circuit for controlling the current provided during short-circuit and arc intervals, respectively. A transistor in series with the power supply is controlled in response to either of the control circuits.

Abstract: Welding of similar and dissimilar metals such as fine wires of gold, silver, brass and others to provide required strength without marring the surfaces of the link is accomplished by mounting an electrode (75,264) a selected distance from the surfaces to be welded. A first high voltage ionizing arc of a selected atmosphere between the electrode and the surfaces to be welded is followed by a low voltage, high amperage welding arc. An electrode (75) is mounted in a discontinuous link forming machine (10) so that it can be oriented in optimum position relative to the work piece (9). An electrode (264) is mounted in an automatic chain making machine (200 ) so that it can be optimally adjusted in x and y directions employing target adjustment block 320, as well as in the z direction employing vertical adjustment block 290.

Abstract: A three-phase thyristor (42, 43) controlled welding output supply requiring only a single firing pulse of short duration per phase per half cycle is shown. Once a firing pulse has been provided (122), a holding impedance (40) connected between the output electrodes (32, 34) is provided to the neutral terminal (18) of a wye wound secondary (17) to provide a path for holding current independently of the load presented by the arc. An improved firing control circuit includes in addition to the normal firing capacitor (82), a negative phase angle impedance (86, 87, 88) attached to one end of a conventional breakdown device (117) used to fire a master thyristor gate (119). Stepped up voltage (60) is provided to the control circuit for greater noise immunity. Also shown is a remote control (151) for controlling a reversible motor (150) to drive through a slip clutch (140), the main voltage controlling variable impedance (80).

Abstract: A hot-wire arc welding apparatus comprises a non-expendable electrode, means for supplying a current to initiate an arc between the nonexpendable electrode and a workpiece, an arc current control means for controlling the current from the supplying means, a wire feed means for feeding a filler wire into the arc, a wire feed control means for controlling the wire feed means to feed the filler wire at a given rate of feed, a voltage applying means for applying a voltage between the filler wire and the workpiece, a wire voltage control means for controlling the voltage from the voltage applying means, and a reference voltage generator for generating an output voltage which increases gradually or incrementally with time, each of the arc current control means, the wire feed control means, and the wire voltage control means being connected to the reference voltage generator and responsive to the output voltage therefrom for controlling the operation thereof.

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 D.C. welder includes an engine-driven D.C. generator, a polarity-revers switch which can change the direction of current flow through the field winding of that generator to provide a positive or negative polarity at the welder output terminals, a circuit that automatically permits only uni-directional current flow through that field winding during the starting of the engine, and a further circuit that energizes a solenoid to close contacts which enable that generator to operate as the starting motor for that engine but which thereafter de-energizes that solenoid and then keeps it de-energized until the engine is at, or close to, rest.

Abstract: A hot wire welding system including a non-melting metal electrode, a supply of filler metal to be fed to a weld puddle formed by an arc, a D.C. power source for supplying both an arc current and a filler metal heating current, a first control circuit for controlling the filler metal heating current with a constant voltage characteristic, and a second control circuit for controlling the arc current with a constant current characteristic. By eliminating one of the two power supplies which was required in prior art systems, a significant reduction in size and complexity is obtained.

Abstract: An electric welder has magnetic cores with windings thereon which perform the functions of transformer windings as well as the functions of magnetic amplifier windings. The secondary windings, on each pair of those magnetic cores, are connected in series relation; and, similarly, the control windings on that pair of magnetic cores are connected in series relation. One of those control windings can have the voltage across it reduced to essentially-zero to cause a high voltage to be developed across the control winding on the other of that pair of magnetic cores--with consequent prompt saturation of that other magnetic core and with the development of an output pulse by the secondary windings on that pair of magnetic cores.

Abstract: The voltage supplied to the welding electrode of a welding system repeatedly and accurately charges an energy storage device by directly sensing the charging voltage across the storage device and comparing the sensed voltage to a reference voltage to produce a control signal and by using the control signal to control the welding system. The charge storage device is charged through the part to be welded to warm the part and improve the weld.

Abstract: An electric arc saw and a method for operating the saw for cutting or slitting metallic objects by melting a narrow kerf into the object. The method provides for determining the minimum threshold current that is necessary to initiate the cutting operation. The normal cutting current exceeds the threshold current and during the cutting operation the blade is advanced through the object at a speed which is continuously monitored and varied as required to maintain the current flow between the blade and the object substantially constant. The arc saw is constructed so that cuts in three mutually perpendicular directions can be made. The blade is mounted to a vertically disposed, hollow piston that reciprocates in a cylinder mounted to and movable along a cross-head. The piston can be pivoted about its axis to align the blade with the different cutting directions. Electric busbars and power lines for rotating the blade extend through the hollow interior of the piston.

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: Data generated by an encoder with phase quadrature outputs, for instance a displacement transducer in a resistance spot welder control system, is read out of the interface to the computer in a format compatible with computer languages. The quadrature signals are converted to pulses representing positive and negative unit changes of displacement, and fed to an up-down counter which has signed two's complement values at its output. The most recent displacement data is read out while the counter continuously tracks the encoder.

Abstract: An inductor for heating rotating metal workpieces, especially for surface hardening the running surfaces, transition radii and shoulders of camshafts to different depths, has two or more heating regions which can be brought into the required heating position by changing the direction of rotation of the workpieces and, when the inductor has more than two heating regions, by using a movable abutment. When the inductor has two heating regions, then change from one region to another is achieved by simply changing the direction of workpiece rotation so that friction causes the inductor to be displaced. When the inductor has, for example, three heating regions (13, 14, 15), then an abutment (11) is used to control the inductor displacement. For more rapid displacement of the inductor or for cases where the workpiece is stationary, an external pusher device may be used.

Abstract: A method and apparatus for forming a ball on a wire by spark discharge and for bonding the wire to a microcircuit is disclosed. The apparatus includes an electrode, a wire holder supporting a wire and forming a spark discharge gap between the tip of the wire and the electrode, first and second D.C. supply circuits, and an arrangement for bringing the wire ball into contact with a microcircuit and bonding the ball to the microcircuit. The first supply circuit provides a higher voltage and lower current than the second supply circuit and includes a capacitor of smaller value and charging, discharging resistors of higher value than corresponding capacitors and resistors in the second circuit. A control circuit initially connects the higher voltage across the wire and electrode to initiate an arc discharge and thereafter connects the lower voltage source across the gap form the ball.

Abstract: A circuit for pulsing the output of a dc power supply (2) connected across a load such as a welding arc. The circuit has a first SCR (12) connected in parallel with a resistor (14). The SCR (12) controls the pulse current and the resistor (14) controls the background current. Each pulse is terminated by the action of a second SCR (18) and a capacitor (16) connected across the first SCR (12) by applying a control pulse to the gate of a second SCR (18). The capacitor (16) is charged by a power supply (20) and is connected by the second SCR (18) so that the first SCR (12) is reverse biased and hence is turned off to terminate the pulse. Immediately the first SCR (12) turns off, the capacitor (16) is charged in the opposite sense to the charge derived from the power supply (20) and this in turn causes the second SCR (18) to be reversed biased by conduction through the resistor ( 14) and turned off a short time after the first SCR (12) is turned off.