A pulse arc welding machine in which the repetition frequency of the pulse currect is unaffected by the frequency of the power source and the mean value of the pulse current applied can be accurately controlled over a broad range while the arcing is maintained stable. A pulse peak current supplying circuit is connected in series with an arcing region formed between a consumable wire electrode and a material to be welded between the output terminals of a standard direct current source while a base current supplying circuit is connected in parallel with the pulse peak current supplying circuit. The pulse peak current supplying circuit and the base current supplying circuit are both composed of a switching element such as a transistor coupled in series with an inductive element. Diodes are provided for suppressing high voltage transients in the circuit.

Pulse arc welding machine

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

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

PURPOSE:To obtain a flat bead shape and to decrease generation of a spatter by supplying high welding current from the stage when an arc is generated and decreasing the welding current when the sign for a short-circuit is detected thereby performing consumable electrode type arc welding. CONSTITUTION:A high current period maintaining the welding current to be supplied from a welding power source 14 at a high level is provided as long as possible to form a flat bead shape in a consumable electrode type arc welding method which repeats alternately the short-circuit and arc generation between a welding wire 1 fed by a welding wire feed motor 13 and base metals 4. A voltage fluctuation is further detected by a welding voltage detecting circuit 16 and is inputted via an arc detecting circuit 15 and a differentiating circuit 21 to a short-circuit predicting circuit 18. When the sign for the short-circuit is detected in said circuit by the fluctuation of the welding voltage inputted thereto, a switch 19 is changed over from the terminal 19a on the side of a high current setting circuit 20 to the terminal 19b on the side of a low current setting circuit 22 to decrease the welding current to a low level and to maintain the low current thereby waiting for the short-circuit between the wire 1 and the base metals 4.

Method for controlling output of welding power source

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

Current waveform control in gas shielded arc welding for robotic systems

An arc welding machine having a strap sliding to advance with advance of the welding position, wherein an electric conductor is disposed on the strap at a position not facing a welding groove with the electric conductor being insulated from the strap, and electric current being applied to the electric conductor while it is being cooled by water, to thereby control the arc direction.

Tokuji Maruyama

Papers

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

Method for controlling output of welding power source

Method and device for controlling welding power supply

Current waveform control in gas shielded arc welding for robotic systems

Arc welding machine