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

A three stage power source for an electric arc welding process comprising an input stage having an AC input and a first DC output signal; a second stage in the form of an unregulated DC to DC converter having an input connected to the first DC output signal, a network of switches switched at a high frequency with a given duty cycle to convert the input into a first internal AC signal, an isolation transformer with a primary winding driven by the first internal high frequency AC signal and a secondary winding for creating a second internal high frequency AC signal and a rectifier to convert the second internal AC signal into a second DC output signal of the second stage, with a magnitude related to the duty cycle of the switches; and, a third stage to convert the second DC output signal to a welding output for welding wherein the input stage has a regulated DC to DC converter with a boost power switch having an active soft switching circuit.

Three stage power source for electric ARC 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 system to weld or join workpieces employing a high intensity energy source to create a weld puddle and at least one resistive filler wire which is heated to at or near its melting temperature and deposited into the weld puddle.

Method and system to start and use combination filler wire feed and high intensity energy source for 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

A method of controlling the output of a power source in consumable electrode arc welding in which a short circuiting phase and an arcing phase alternately take place between a consumable electrode and a workpiece in a shielding gas atmosphere, the method being characterized by repetition of a cycle of operation consisting of: a first stage of maintaining the output welding current at a first value of a relatively low level upon establishment of a short circuit across a gap between a consumable electrode and a workpiece; a second stage of maintaining the welding current at a second value of a relatively high level succeedingly to the first stage; a third stage of lowering the welding current to a third value of a low level upon detection of necking as a premonition of rupture of short circuiting molten metal between the electrode and workpiece; a fourth stage of, upon generation of an arc across a gap between the electrode and workpiece subsequent to the third stage, maintaining the welding current at a fourth value of a relatively high level exceeding the value of average welding current; and a fifth stage of maintaining the welding current at a fifth value of a relatively low level until the gap between the electrode and workpiece is short-circuited, under control of substantially constant current characteristics to feed current of constant level irrespective of variations in arc length.

Output control of short circuit welding power source

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

PURPOSE:To prevent generation of a spatter and to improve quality of welding by detecting exactly the time when a welding wire is contracted and controlling the electric current on the welding wire. CONSTITUTION:A resistance detector 111 calculates the resistance between a welding wire 103 and a base metal 106 from the ratio between the output signal from a voltage detector 110 and the output signal from a voltage detector 112. The calculated resistance value is impressed on a differentiating circuit 113. The resistance R calculated by the detector 111 in the circuit 113 is differentiated with a time (t) and dR/dt is outputted. The differential resistance value dR/dt is impressed on a computer 114, which compares the value with the set value set by a setter 115. The comparator 114 impresses the control signal to a welding power source 101 when the differential resistance value is larger than the set value to change over a switch 120 to the setter 121 on a low current side, thereby controlling the output of the power source 101 and decreasing the current on the wire 103. The set value of the setter 115 is determined in accordance with the differential value of the resistance value between the wire and the base metal when the wire is contracted.

Method and device for controlling power source for short-circuit transfer welding

PURPOSE:To decrease generation of spatter and to prevent failure in regeneration of an arc by decreasing the short-circuit current of a consumable electrode wire upon detection of the necking of a droplet and returning the short-circuit current to the prescribed short-circuit current or above when no arc is generated. CONSTITUTION:A comparator 114 compares the set value set by a setter 115 and the output from a voltage detector 110 and judges that a consumable electrode wire is necked when the voltage excceeds the set value. The comparator 114 applies a control signal to a welding power source 101 and changes over a switch to a setter 121 on a low current side to decrease the current on the consumable electrode wire 103. A timer 123 starts clocking from the point of the timer when the necking of the droplet is detected by the signal of the comparator 114 and changes over a switch 120 to a setter 124 to supply the original short-circuit current or slightly larger current if no arc is regenerated within a specified time. The end of the consumable electrode wire is melted and the arc is again generated by the short-circuit current.

Controlling method of current for welding accompanying short circuit transfer

PURPOSE:To decrease the amt. of the spatter to be generated by supplying the current during generation of an arc with the large current within the prescribed time after the generation of the arc and with the small current of a constant current characteristic after the prescribed time. CONSTITUTION:A power source for welding which supplies current to a welding wire and which has a constant voltage characteristic and constant current characteristic is used in the welding in which a short circuit and the generation of the arc are alternately repeated between the welding wire and base materials while the welding wire using a consumable electrode wire is fed in shielding gas at the constrolled speed toward the base materials. The relatively large current is supplied at the constant voltage characteristic to the welding wire for the specified time after the generation of the arc. A step is given to the current and the low current is supplied at the constant current characteristic to the welding wire after the specified time during generation of the arc.

Takashi Saito

Papers

Output control of short circuit welding power source

Method for controlling output of welding power source

Method and device for controlling power source for short-circuit transfer welding

Controlling method of current for welding accompanying short circuit transfer

Controlling method of current for welding accompanying short circuit