JP3697909B2 - Arc start method and apparatus for multi-electrode welding torch - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an arc start method and apparatus for a multi-electrode welding torch.
[0002]
[Prior art]
In recent years, TIG welding torches used for groove welding by butting members such as plate materials have been developed with electrodes having a multi-electrode structure so that high-speed welding can be performed while allowing a large current to flow. ing.
[0003]
4 (a) and 4 (b) show a multi-electrode TIG welding torch 1 developed for narrow groove welding. Flat grooves 3a and 3b are formed on the left and right side surfaces of an elongated flat plate-like insulating plate 2. FIG. Are provided along the longitudinal direction, and strip-like electrodes (tungsten electrodes) 4a and 4b connected to different power sources are inserted into the flat grooves 3a and 3b, respectively, and an insulating plate is formed by these two electrodes 4a and 4b. 2 having a flat cross-sectional shape in which the welding wire 5 is inserted into a boundary portion between the rear end surface of the insulating plate 2 and the wire guide 2a made of an insulator disposed in contact with the rear end surface. The electrode structure 6 is configured, and the base end side, which is the upper part of the electrode structure 6, is inserted and supported by the torch body 9 through the split structure feeding collet 7 and the collet body 8 holding the feeding collet 7. Further, the electrode structure 6 A tip comprising an end portion, is a structure in which so as to required length protruding from the distal end of the gas cup 11 for ejecting the shielding gas 10. The power supply collet 7 is divided at a position where the insulating plate 2 is sandwiched, and an insulating block 7a is interposed in the divided portion.
[0004]
[Problems to be solved by the invention]
However, in the case of the TIG welding torch 1 having the multi-electrode structure, for example, when welding the groove 13 formed between the base materials 12 as shown in FIG. When an arc is generated between the base material 12 by inserting it into the base material 12, it is necessary to simultaneously touch the base material 12 with the tips (cathode spots) of both electrodes 4a and 4b. Due to distortion or the like, as shown in FIGS. 5B and 5C, only one of the electrodes 4a or 4b may be touched, and the arc start may not be performed smoothly.
[0005]
Incidentally, there is a high-frequency start method as a method of simultaneously generating arcs from two electrodes. In this case, however, it causes a malfunction due to noise to a microcomputer-like control device or the like.
[0006]
Therefore, the present invention intends to provide an arc start method and apparatus for a multi-electrode welding torch that can simultaneously generate an arc from two electrodes without using a high frequency when welding to a base material. It is.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a base material until the tips of the two electrodes of a multi-electrode welding torch having an electrode structure in which two electrodes are arranged in parallel touch the base material simultaneously. On the other hand, the step of separating the welding torch once, the step of rotating the electrode structure by a required angle, and the step of bringing the welding torch again approach are repeated, and the two electrodes touch the base material simultaneously. After confirming this, an arc start method for a multi-electrode welding torch in which a voltage is applied to the two electrodes to cause the welding torch to move away from the base material to generate an arc simultaneously from the two electrodes. In addition, an electrode structure rotating mechanism for rotating the electrode structure is provided in a multi-electrode welding torch having an electrode structure in which two electrodes are arranged in parallel, and a voltage is applied to the two electrodes. Voltage setting device, a control command device for driving the torch moving unit based on a voltage set by the voltage setting device, and a touch detector for individually detecting contact of the two electrodes with the base material And a comparator for operating the voltage controller when receiving the outputs from the two touch detectors at the same time, and the comparator is connected to the control commander from one of the touch detectors. When only the output is received, after the welding torch is once separated from the base material, the electrode structure is rotated, and then the welding torch is made to execute the operation of bringing the base material closer again. An arc start device for a multi-electrode welding torch having the above configuration.
[0008]
When the welding torch is brought close to the base material, the touch detector detects whether or not the tip of the two electrodes touched the base material at the same time. If not touched simultaneously, a control command based on the output from the comparison calculator After the welding torch is once separated from the base material by driving the torch moving unit in response to a command from the vessel, the electrode structure is rotated by a required angle by driving the electrode structure rotating mechanism, Further, the process of bringing the welding torch closer to the base material by driving the torch moving unit is repeated.
[0009]
When the touch detector signal confirms that the tip of the two electrodes touched the base material at the same time, the voltage controller is actuated by a command from the comparison computing unit, so that the voltage is simultaneously applied to the two electrodes. Then, the torch moving unit is driven by a command from the control commander, and the welding torch is separated from the base material by a required distance, whereby a simultaneous arc is generated from the tips of the two electrodes.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0011]
1 and 2 show an embodiment of an arc start device for a multi-electrode welding torch according to the present invention. In the TIG welding torch 1 having the same configuration as shown in FIGS. The collet body 8 that holds the structure 6 via the power supply collet 7 is configured to be rotatably supported by the torch body 9, and the upper end of the collet body 8 that protrudes from the upper end surface of the torch body 9. A large-diameter ring gear 16 is attached to the outer periphery of the part, and a pinion 17 is engaged with the ring gear 16, and the pinion 17 is attached to a drive shaft 18 a of a motor 18 installed on the outer side of the torch body 9. An electrode structure rotating mechanism 19 is configured to transmit the driving force to the collet body 8 via the pinion 17 and the ring gear 16 so that the electrode structure 6 can be rotated. Furthermore, by attaching a rotational angle detector 20 to the motor 18, to be fed back to the control command 22 the arc start control device 21 which will be described later signal of the rotational angle detector 20.
[0012]
As shown in FIG. 2, the arc start control device 21 drives a torch moving unit 24 based on a voltage controller 23 for applying a voltage to two electrodes and a set voltage by the voltage controller 23. Touch detectors 15a and 15b, each of which includes a control command device 22 for maintaining the distance of the TIG welding torch 1 relative to the base material, and individually detecting contact of the electrodes 4a and 4b of the electrode structure 6 with the base material. And a comparator 14 for operating the voltage controller 23 when the outputs from the touch detectors 15a and 15b are received at the same time. When the device 14 receives only the output of one of the touch detectors 15a or 15b, the torch moving unit 24 is driven away from the base material, and then the motor 18 is rotated by a predetermined angle. It was allowed to, certain torch moving unit 24 as a configuration remembering function to to be driven in the approaching direction to the base material.
[0013]
The touch detectors 15a and 15b apply a minute voltage between the power cable of the electrodes 4a and 4b and the ground, and when the electrodes 4a and 4b touch the base material, the minute voltage becomes zero. It can be detected.
[0014]
When welding the groove 13 formed between the base materials 12 as shown in FIG. 5, the groove is touched until the tips of the two electrodes 4 a and 4 b of the electrode structure 6 touch the bottom of the groove 13 simultaneously. 13, the step of once separating the TIG welding torch 1, the step of rotating the electrode structure 6, and the step of bringing the TIG welding torch 1 closer again are repeated, and the two electrodes 4 a, After confirming that 4b touches the bottom of the groove 13 at the same time, a voltage is applied to the two electrodes 4a and 4b to separate the TIG welding torch 1 by a required amount, thereby removing the two electrodes 4a and 4b. At the same time, an arc is generated, and thereafter, AVC (arc voltage control) is performed.
[0015]
Referring to FIGS. 1, 2 and 3 in detail, first, when the torch moving unit 24 is driven by a command from the control commander 22 to bring the TIG welding torch 1 close to the base material, two Whether the electrodes 4a and 4b touch the base material at the same time is detected by the touch detectors 15a and 15b. When the electrodes are not touched at the same time, only the output signal of either one of the touch detectors 15a or 15b is compared. Is input to the device 14. In this case, the control command unit 22 drives the torch moving unit 24 based on the output of the comparison computing unit 14 to temporarily avoid the TIG welding torch 1 from the base material, and then turns on the motor 18 of the electrode structure rotating mechanism 19. The above-described steps are performed until the electrode structure 6 is rotated by a predetermined angle, and the torch moving unit 24 is driven to issue a command to bring the TIG welding torch 1 close to the base material again and the simultaneous touch is detected. Make it happen repeatedly.
[0016]
On the other hand, when it is detected by the output signals of the touch detectors 15a and 15b that the tips of the two electrodes 4a and 4b have touched the base material at the same time, the voltage controller 23 is activated by the output signal of the comparator 14. As a result, a voltage is simultaneously applied to the two electrodes 4a and 4b, and subsequently, the torch moving unit 24 is driven by a command from the control command device 22 based on the set voltage by the voltage controller 23, whereby TIG The welding torch 1 is separated from the base material by a required distance. As a result, arcs are generated simultaneously from the tips of the two electrodes 4a and 4b, and thereafter AVC is executed.
[0017]
Although the TIG welding torch has been described in the above embodiment, it may be a MIG welding torch in which two consumable electrodes are arranged in parallel to form an electrode structure, and other within the scope of the present invention. Of course, various changes can be made.
[0018]
【The invention's effect】
As described above, according to the arc start method and apparatus for a multi-electrode welding torch according to the present invention, the tips of the two electrodes of the multi-electrode welding torch having an electrode structure in which two electrodes are arranged in parallel are simultaneously formed. The process of detecting whether or not to touch the base material at the same time with a touch detector, and driving the torch moving unit in response to a command from the control commander until the base material is touched at the same time, thereby temporarily separating the welding torch from the base material And the step of rotating the electrode structure by driving the electrode structure rotating mechanism and the step of bringing the welding torch closer to the base material again by driving the torch moving unit. After confirming that the two electrodes touched the base material at the same time, the voltage controller is operated to apply a voltage to the two electrodes at the same time to Since the arcs are generated from the two electrodes at the same time, it is possible to prevent malfunctions due to noise to the control device etc. as in the high frequency start method and to improve the reliability. Demonstrate.
[Brief description of the drawings]
FIG. 1 is a schematic side view of a TIG welding torch showing an embodiment of an arc start device for a multi-electrode welding torch according to the present invention.
FIG. 2 is a block diagram of an arc start control device.
FIG. 3 is a flow based on the block diagram of FIG.
FIGS. 4A and 4B show an example of a TIG welding torch, where FIG. 4A is a schematic side view, and FIG. 4B is an enlarged view in the AA direction of FIG.
FIG. 5 shows an arc start of a TIG welding torch. (A) is a schematic view of the state where the tips of two electrodes are simultaneously touching the base material, and (B) is a diagram showing only the tip of one electrode. Schematic of a state where the base material is touched, (c) is a schematic diagram of a state where only the tip of the other electrode is touching the base material.
[Explanation of symbols]
1 TIG welding torch (welding torch)
4a, 4b Electrode 6 Electrode structure 12 Base material 14 Comparison calculator 15a, 15b Touch detector 19 Electrode structure rotating mechanism 22 Control commander 23 Voltage controller 24 Torch moving unit

Claims (2)

A step of temporarily separating the welding torch from the base material until the tips of the two electrodes of the multi-electrode welding torch having an electrode structure in which the two electrodes are arranged in parallel touch the base material simultaneously; The step of rotating the structure by the required angle and the step of bringing the welding torch closer again are performed, and after confirming that the two electrodes touch the base material at the same time, voltage is applied to the two electrodes. An arc start method for a multi-electrode welding torch characterized in that an arc is simultaneously generated from two electrodes by applying a required amount to separate the welding torch from the base material by a required amount. A multi-electrode welding torch having an electrode structure in which two electrodes are arranged in parallel is provided with an electrode structure rotating mechanism for rotating the electrode structure, and voltage setting for applying a voltage to the two electrodes A control commander that drives the torch moving unit based on a voltage set by the voltage setting device, a touch detector that individually detects contact of the two electrodes with the base material, A comparator for operating the voltage controller when receiving the output from the touch detector at the same time, and the comparator receives only the output from one of the touch detectors. If the welding torch is once separated from the base material, the electrode structure is rotated, and then the welding torch is again configured to perform the operation of approaching the base material. That features Arc start apparatus for a multi-electrode welding torch.

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