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: 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: The present invention provides a capacitor charging circuit for a discharge type welding tool. The circuit includes a rectifier for producing rectified pulsating currents, a capacitor to be charged, a thyristor between the rectifier and the capacitor. A pulse generator receives the pulsating currents and in turn produces a pulse at each hill of the pulsating current. The thus produced pulse is applied to the gate of the thyristor which turns the thyristor on. A charge potential detecting circuit directly measures the charge potential across the charged capacitor and transfers a signal change, according to the level of the capacitor potential, to the pulse generator so as to thereby control the timing of the pulse generation at each hill of the pulsating current.

Abstract: In an electrical resistance welder, whenever a material to be welded approaches the welding electrodes, a start signal is produced, so that welding current is supplied to the welding transformer in one direction for a certain period of time set by a time limit circuit, with the polarity changing in response to the start signal, whereby, even if materials are repeatedly fed for welding at high speed, they can be positively welded in a uniform manner.

Abstract: Method and apparatus for forming a ball at the end of bonding wire or lead wire in a capillary wire holding and bonding tool is described suitable for ball bonding of copper and aluminum lead wire to integrated circuit chips. A ball is formed by substantially enclosing the end of the bonding wire in a shroud or shield, flooding the shroud or shield and the end of the bonding wire with an inert gas, and generating a controlled pulse train of a preset count of electrical pulses for establishing arc discharge between the wire and the shroud or shield. The method permits precise control and metering of energy delivered by controlling the parameters of the pulses of the pulse train for melting and forming a ball of uniform quality without oxidation of the metal. Corresponding apparatus and circuitry are described which may be retrofitted into stock ball bonding machines or provide new machines.

Abstract: This application relates to a method and apparatus for welding together small oxide coated components by driving a sharp edge or point of one part into a face of another part and then discharging electrical energy, for example, a capacitively stored electrical current through the joint. Precision micrometer control of the distance one part accelerates toward the other along with continuously adjustable spring tension are used to program the inelastic collision of the two parts. The electrical discharge circuit is controlled to provide a controlled arc after collision.

Abstract: An electrical discharge is applied to a wafer mounted in a wafer holder. The wafer includes at least one conducting region covered by an insulating layer. The discharge causes a conductive channel from the conductive region through the insulating layer. The conductive channel provides a relatively low impedance path suitable for conducting away electrons which are injected into the region during processing steps such as electron beam exposure.

Abstract: This percussion welding power supply supplies welding energy through an arc between two work pieces that are forced together during or immediately following arcing. The power supply comprises a welding transformer having a primary winding and a secondary winding. Across the secondary winding, welding electrodes are connected for supplying welding current between the secondary winding and the pair of work pieces to be welded together. The power supply further comprises a capacitor bank having a pair of output terminals and means comprising electronic switching means in series with the primary winding and the output terminals for selectively connecting the output terminals across the primary winding. Control means is provided for rendering the switching means conductive, thereby causing the capacitor bank to discharge through the switching means and the primary winding to effect a welding operation.

Abstract: This application relates to a method and apparatus for welding together small oxide coated components by driving a sharp edge or point of one part into a face of another part and then discharging electrical energy, for example, a capacitively stored electrical current through the joint. Precision micrometer control of the distance one part accelerates toward the other along with continuously adjustable spring tension are used to program the inelastic collision of the two parts. The electrical discharge circuit is controlled to provide a controlled arc after collision.

Abstract: A welding power supply that includes a combination of series and shunt regulating circuits controlled by a single controller, in the charging circuit for a welding energy storage capacitor.The series circuit, which includes a series thyristor, regulates the supply of charging energy to the capacitor from a full wave rectified power source. The series circuit also phases forward to replenish charge lost by leakage by controlling the thyristor firing angle as a function of the difference between the capacitor charge and a pre-selected value.The shunt regulating circuit utilizes a shunt thyristor coupled to the output of the power source to divert energy delivery away from the energy storage capacitor when a preselected charge level on the capacitor is reached. The shunt regulating circuit shorts out the unneeded balance of the charging cycle thereby eliminating capacitor voltage overshoot during the charging process.

Abstract: A self-contained, portable, underwater stud welder includes a hand-held welding gun and a battery powered backpack. The welder uses a bank of rechargeable nickel-cadmium batteries which charges a storage inductor, the energy of the inductor being transferred to a bank of capacitors, providing a high efficiency method of charging the capacitor bank so the battery bank is kept small.

Abstract: This invention relates to a method and apparatus for wire bonding a variety of metals in the interconnection of semiconductor chips to electronic package substrate circuitries. A pair of electrically conducting bonding tip members are provided which are electrically isolated from one another and which are constructed of a material having a high resistivity. The wire is positioned beneath the tip members and a load is applied to the members to force the wire against a land on the substrate. A voltage source is provided to apply a voltage between the tip members. Activitation of the voltage source results in current flow through the tips and through the wire, in series, causing heating of the tip members and of the section of wire beneath them. Diffusion bonding will initiate before a significant amount of oxidation has had time to occur.

Abstract: A method for the connection of sheet metal panels coated on at least one surface with a layer by the electrical fusin of a metal, wherein the improvement comprises the steps of supplying an electric current for the fusion of metal indirectly along the sheet metal of at least one panel to the zone at which said panels are to be connected to each other, and keeping the temperature of an outer layer of at least one of said panels below the melting point of said layer.

Abstract: Bonds are made between two work pieces by using foils exploded by electrical energy typically stored in a large capacitor. To increase the uniformity of the bond area, a foil having at least one slit cut in the direction of current flow is used. The foil strips separated by the slit are attracted together by the pinch effect when current is applied, tending to eliminate loss of foil through a jetting action during explosion. Platings are made by pressing the foil between the work piece and a plastic layer to which the foil does not adhere. In both bonding and plating, the capacitor is charged with energy sufficient to bring the foil just to its boiling point. This "tuning" is more efficient and minimizes heat and blast effects that might otherwise damage a small work piece.

Abstract: Bonds are made between two work pieces by using foils exploded by electrical energy typically stored in a large capacitor. To increase the uniformity of the bond area, a foil having at least one slit cut in the direction of current flow is used. The foil strips separated by the slit are attracted together by the pinch effect when current is applied, tending to eliminate loss of foil through a jetting action during explosion. Platings are made by pressing the foil between the work piece and a plastic layer to which the foil does not adhere. In both bonding and plating, the capacitor is charged with energy sufficient to bring the foil just to its boiling point. This "tuning" is more efficient and minimizes heat and blast effects that might otherwise damage a small work piece.

Abstract: A capacitance discharge stud welding apparatus which comprises a housing. A coil is positioned in the housing and an armature is located within the coil and is movable between first and second positions relative to the coil. A stud chuck is provided for the purpose of holding a stud and is connected to the armature for movement therewith. A relatively light spring constantly urges the armature and the stud chuck toward the first position of the armature in the direction of a metal member to which a stud held by the chuck is to be welded. Engagement of the stud held by the chuck with a metal member causes the armature to move to the second position relative to the coil and against the urging of the light spring. An electrical welding current circuit is provided and electrical connection means connect the welding current circuit to the chuck and to a stud held thereby.