A method and apparatus for welding include initiating a pulse welding process includes initiating a welding arc by providing CC type welding power, maintaining the arc by providing CV type power. Then, pulse type welding power is provided. The method and system can be used to start short circuit, or other welding processes by providing short circuit power, or welding power of a given mode, instead of providing pulse power. Also, in one alternative, a method and system of initiating a pulse, short circuit, or given welding process includes initiating a welding arc by providing CC type welding power at least until a pseudo-equilibrium for the arc is established. Then, providing welding power in a pulse, short circuit, or the given mode.

Method and apparatus for welding

Apparatus and method to reduce spatter and allow better semi-automatic welding in short circuiting arc welding of the type using a single D.C. power supply for causing a welding current to pass through a welding wire extending variable distances from a holder and between the welding wire and a workpiece at a molten metal pool on the workpiece. The welding current flows in response to an arc voltage while the welding wire is fed from the holder toward the workpiece whereby the welding wire is subjected to a succession of welding cycles each of which include an arcing condition during which the wire is spaced from the pool and a short circuit condition during which a molten metal ball formed on the end of the wire contacts the metal pool and then transfers from the wire to the workpiece by a necking action. In this type of welding operation, the invention involves the application of a preselected amount of energy into the wire during the arcing condition for each welding cycle, which preselected amount of energy slightly exceeds the known value of energy necessary to melt a given volume of metal to form a consistent molten metal ball onto the end of the wire. This constant energy is divided between the resistance heating of the wire extending from the wire holder and the anode heating caused by the arc during each arcing condition of a cycle. Consequently, constant energy is inputted to the end of the wire irrespective of changes in the amount of wire extension or stick-out.

Apparatus and method of short circuiting arc welding

A method and device for controlling a power supply for arc welding in a manner to reduce spatter when the power supply is employed for depositing metal from a welding wire or electrode onto a workpiece by the short circuiting transfer mode wherein a welding current causes the welding wire to alternate between a short circuit condition and an arc condition with metal transfer occurring during a short circuit condition. This method and device includes the concept of shifting the welding current to a background current value in response to a short circuit condition, holding the welding current generally at the background current level for a preselected time, then allowing the welding current to reach the normal unimpeded current level, and causing the holding step to be terminated before the selected time in response to a detected arc condition. This concept provides a predetermined low current condition immediately upon establishing a short circuit between the welding wire or electrode and the workpiece, which low current condition is retained long enough to convert what otherwise would be a spatter-laden momentary short circuit to a short circuit where metal is transferred to the workpiece. Further, the method and device detects the slope of the welding current or voltage and shifts the welding current to the low background current level when the welding current reaches its maximum value just before breakage of the metal from the wire thus reducing the spatter energy when the molten metal breaks from the wire.

Method and device for controlling a short circuiting type welding system

There is provided an improvement in a short circuiting arc welding system comprising a work station with a consumable electrode and workpiece, a D.C. power supply with a positive and a negative terminal, high frequency current control means for applying a welding circuit with a given time-based profile across the work station while the electrode is short circuited and while the electrode is spaced from the workpiece, a welding current circuit means including a first means for creating a first inductive reactance in series with the current control means and work station whereby the welding current follows the time-based profile in accordance with the first inductive reactance. The improvement comprises a background current circuit means between the power supply and the work station and in parallel with the current control means and first means for applying continuously a background current across the work station. This background current circuit means includes a second means for creating a second inductive reactance substantially greater than the first inductive reactance and a resistor means for controlling the background current flowing continuously from the power supply to the work station through the background current circuit means.

System and method of short circuiting arc welding

An improvement in a short circuiting arc welding apparatus of the type including a power supply for causing a welding current of different levels to pass through a welding wire extending at variable extension distances from a holder and between the wire and a workpiece at a molten metal pool on the workpiece. This improvement includes control means for maintaining a generally constant wattage in the wire during the plasma boost portion of the arcing condition as the extension distance from the holder changes. Further, the improvement involves controlling the plasma or arcing condition after a plasma boost by a current curve gradually decreasing from the plasma boost portion toward the background current level for the system.

Apparatus and method of controlling a welding cycle

A method and a device for controlling a welding power supply, employing a control device essentially including a first switch means consisting of at least one switch in element to be turned on and off to control the output current of the power supply, second switch means adapted to be inserted in a welding current attenuating path when the first switch means is in off state, and an impedance means consisting of at least one impedance element connected parallel with the second switch means.

Method and device for controlling welding power supply to avoid spattering of the weld material

A control device essentially including a first switch means (SW5) consisting of at least one switching element to be turned on and off to control the output current of the power supply, second switch means (SWD) adapted to be inserted in a welding current attenuating path when the first switch means is in off state, and an impedance means (RA) consisting of at least one impedance element connected parallel with the second switch means (SWD).

Method and device for controlling welding power supply

PURPOSE:To control satisfactorily transfer to a low current and high voltage arc without spatter in short circuit transfer welding using an output control power source by knowing the contracting condition of an electrode from the change in the current value of a reflux circuit while a switching element is not conducted by short circuit. CONSTITUTION:Current (i) is detected with a current detector 8 in the short circuiting stage of load 7 while a switching element 2 by a DC power source 1 is not conducting. Said current is compared with a set current value 9 and a mode selector switch 22 is actuated by the signal from a timer 21 for the lapse time of the short circuit by the change of the current with time and the detected load voltage in a differentiation circuit 15. A triangular wave generator signal 11 which determines synchronization with the element 2 is matched by a comparator 12 and is made to the pulse of a base driving circuit 13, by which the switching element is made conducting and the welding is transferred to low current and high voltage arc welding. The transfer is made smooth by the timer 21 and the satisfactory welding is accomplished without failure in the equipment.

Method for controlling output of welding power source accompanying short circut transfer

PURPOSE:To enable continuous operation for long time and to improve working efficiency by increasing the current of a consumable electrode wire to the current larger than a short-circuit current when the contraction of a droplet is not detected upon lapse of specified time after start of a short-circuit period. CONSTITUTION:The contraction of the droplet of a consumable electrode wire is detected at the end period of a short-circuit and the short-circuit current is decreased to decrease generation of spatter in welding accompanying short-circuit transfer. The short-circuit current is increased to prevent the consumable electrode wire from sticking to the base material when the contraction of the droplet is not detected for the specified time or longer in the short-circuit period. The failure of arc generation is thus prohibited during repetition of the short- circuit and the arc and the arc is smoothly started.

Method for controlling current of welding accompanying short-circuit transfer

PURPOSE:To prevent generation of spatter by detecting the value near the end point in each switching section of welding current and deciding the generation of necking and decreasing the welding current when the decreased amt. exceeds a reference value. CONSTITUTION:When necking arises, a current detecting signal SI drops and the level of a signal S4 falls as well. However, a signal S6 maintains the level of the signal S4 before one section and therefore the difference between the signals S6 and S4 increases and a signal S7 exceeds a reference value DELTAIE. As a result, the signal S8 of a comparator COM3 rises to an H level and an FF 29 is set then a signal S9 rises to an H level and since the signal of a timer 22 is an H level, an AND gate 32 outputs the signal of the H level then a switching element SW turns off. Welding current I decreases further and an arc is generated again then the signal of a short-circuit detecting circuit 29 falls to an L level and the signals of the timer 22 and the gate 32 fall to an L level. Thereupon the element SW1 contacts with a contact (a) side and a driver 14 is operated by which the current I is controlled until the average value is made equal to the set value SIa.

Sadao Nakanishi

Papers

Method and device for controlling welding power supply to avoid spattering of the weld material

Method and device for controlling welding power supply

Method for controlling output of welding power source accompanying short circut transfer

Method for controlling current of welding accompanying short-circuit transfer

Controlling method of welding power source