JP2000153358A - Automatic welding start control method - Google Patents

Abstract

(57) [Problem] To provide an automatic welding start control method capable of reliably generating an arc without interrupting automatic welding and improving work efficiency. SOLUTION: Before turning on a torch switch 5, a welding voltage is applied between a welding wire 6 and a base material 7 to lower a welding torch 3 as a whole by a required amount. The tip is brought into contact with the base material 7, the touch voltage is monitored by the touch voltage detector 19, and if the touch voltage does not become zero, it is determined that slag exists at that position, and the entire welding torch 3 is removed. The welding torch 3 is raised to the original starting height, and the entire welding torch 3 is advanced by a required amount. The same operation is repeated until the touch voltage becomes zero. At the position where the touch voltage becomes zero, the entire welding torch 3 is returned to the original position. It is raised to the height and the arc start is performed in the same manner as before.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a start control method for automatic welding.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 3, an automatic welding apparatus such as MAG welding or MIG welding includes a control panel 1, a welding machine 2 controlled based on a command from the control panel 1, and a welding machine 2. Welding torch 3, wire feeder 4, torch up / down drive 14, and torch front / rear drive 1 connected to welding machine 2.
5 is provided.

The welding machine 2 includes a torch switch 5 which is turned on / off based on a command from the control panel 1, and a tip of a welding wire 6 of a welding torch 3 and a base metal when the torch switch 5 is turned on. And a welding power supply 8 for supplying an electric current to the wire feeding device 4 in conjunction with the generation of an arc between the wire feeding device 7 and the welding power source 8. A wire feed commander 9 for giving a feed command for the welding wire 6, a current detector 10 for detecting whether or not a welding current is flowing when the torch switch 5 is turned on; A torch up / down movement commander 16 for giving a torch up / down drive device 14 a movement command in the up / down direction (direction of approaching / separating from the base material 7) to the torch up / down driving device 14 based on the command Based on directive To the torch rear driving device 15 and a torch back and forth movement command unit 17 to give a movement command before and after a direction (traveling direction along the base material 7) of the welding torch 3.

In FIG. 3, reference numeral 11 denotes a gas nozzle attached to the tip of the welding torch 3 for blowing a shielding gas such as an inert gas, and 12 denotes a welding wire 6 which is fed from a wire feeding device 4. A contact tip 13 for extending from the tip side of the torch 3 represents a weld bead formed on the joint surface of the base material 7.

In the automatic welding apparatus as shown in FIG. 3, the welding wire 6 is sent out by the operation of the wire feeder 4, the tip of the welding wire 6 is brought into contact with the base material 7, the arc is started, and the inert gas is supplied from the gas nozzle 11 to the inert gas. The welding torch 3 is held at a predetermined height position by the operation of the torch vertical driving device 14 while the welding wire 6 is fed out from the tip of the contact tip 12 in a state where the shielding gas such as is blown to the joint surface of the base material 7 and By moving the welding torch 3 in a required direction by the operation of the torch front-rear drive device 15, a welding bead 13 is formed on the joint portion surface of the base material 7, and automatic welding is performed.

[0006] At the time of arc start, as shown in FIG.
Is turned on, a welding current value command voltage (aV) for setting the welding current value to a predetermined value is applied, and the wire feed command device of the welding machine 2 is further transmitted from the control panel 1. 9, a command to feed the welding wire 6 by a required amount to the wire feeding device 4 is output. When an arc is generated and a welding current flows, the current detector 10 of the welding machine 2 outputs a command. The welding current detection signal is output to the control panel 1 as ON, and the welding is continued as it is.

[0007]

By the way, when a plurality of layers of the weld beads 13 are laminated when performing automatic welding by the automatic welding apparatus as described above, the welding torch 3 is used.
Is moved from the start point to the end point to perform the automatic welding of the first layer, then the arc is ignited again from the end point position, and the welding torch 3 is returned to the start point to form the weld bead 13 of the next layer. Thereafter, the same operation is repeated, or after the first layer is automatically welded by moving the welding torch 3 from the start point to the end point, the welding torch 3 is returned to the start point, and then again at the start point. By igniting the arc and moving the welding torch 3 in the same direction as that of the first layer, a welding bead 13 of the next layer is formed, and thereafter, the same operation is repeated.

However, since slag, which is a non-metallic substance, adheres to the surface of the weld bead 13, the arc is again turned on at the end point or the first start point during automatic welding of the next layer as described above. Even when an attempt was made to arc, current did not flow due to the slag, and arcing was not generated in some cases.

As described above, when no arc is generated and the welding current does not flow, as shown in FIG. 4, the welding current detection signal from the current detector 10 of the welding machine 2 to the control panel 1 is turned on. And output an off signal, an emergency stop is issued, an alarm is issued, and the worker removes the slag adhered to the surface of the welding bead 13 using a wire brush or the like. If the slag attached to the surface of the welding bead 13 is removed using a wire brush or the like, the automatic welding is interrupted, leading to a reduction in work efficiency, and it is not preferable that a person enters the operating area of the automatic welding device. Was.

The present invention has been made in view of the above circumstances, and provides an automatic welding start control method capable of reliably generating an arc without interrupting automatic welding and improving work efficiency. It is.

[0011]

SUMMARY OF THE INVENTION The present invention is to start automatic welding in which a torch switch is turned on, a welding current value is set, a welding wire is sent out, and a tip of the welding wire is brought into contact with a base material to perform an arc start. In the control method, before turning on the torch switch, with the touch power supply circuit closed and a touch voltage applied between the welding wire and the base material,
The entire welding torch is brought close to the base material, the tip of the welding wire is brought into contact with the base material, and the touch voltage is monitored. If the touch voltage does not become zero, the entire welding torch is removed from the base material by a required amount. Move the welding torch away by a required amount along the base material, repeat the same operation until the touch voltage becomes zero. The present invention relates to a start control method for automatic welding, wherein an arc start is performed after a circuit is opened.

According to the above means, the following effects can be obtained.

For example, after the automatic welding of the first layer is performed, when the arc is again ignited at the end position or the first starting point in order to perform the automatic welding of the next layer, the torch switch is turned on. First, in a state where a touch voltage is applied between the welding wire and the base material, the entire welding torch comes close to the base material and the tip of the welding wire contacts the base material.

At this time, the touch voltage is monitored,
If the touch voltage does not become zero, it is determined that there is slag at that position, and the entire welding torch separates from the base material by a required amount and moves along the required amount along the base material, and the touch voltage is reduced. The same operation is repeated until becomes zero, and at the position where the touch voltage becomes zero, the entire welding torch separates from the base material by a required amount, and an arc start is performed.

In general, the slag does not cover the entire surface of the weld bead, but is scattered at a certain interval. Therefore, even if the slag exists at the end position or the first start point, the slag exists as described above. If the position of the welding torch is moved by a required amount along the base material, the slag will reach a position where no slag exists, and if an arc start is performed at that position, the arc will be generated reliably. Become.

As a result, there is no need for the operator to enter the operating area of the automatic welding apparatus in order to remove the slag adhered to the surface of the welding bead using a wire brush or the like as in the prior art, and the automatic welding is interrupted. Work efficiency is also improved.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an example of the embodiment of the present invention. In the drawings, the portions denoted by the same reference numerals as those in FIGS. 3 and 4 represent the same components, and the basic configuration is as follows. 3 and FIG. 4 is the same as the conventional one, but the feature of the illustrated example is that the touch voltage (V) is applied between the welding wire 6 and the base material 7 as shown in FIG. 1 and FIG. ) Is provided separately from the welding power supply 8 and a touch power supply circuit open / close switch 20 for opening and closing the circuit of the touch power supply 18 is provided to determine whether the touch voltage has become zero (V = 0). Before turning on the torch switch 5, a touch voltage application command is output from the control panel 1 to the touch power supply 18, the touch power supply circuit open / close switch 20 is closed, and the welding wire 6 is connected. Touch voltage applied between base material 7 In state, and outputs the lowering drive command of the welding torch 3 to the cabinet 1 to the torch up-down driving device 14,
Lower the entire welding torch 3 by the required amount Δh (base material 7).
The tip of the welding wire 6 is brought into contact with the base material 7 and the touch voltage is monitored by the touch voltage detector 19. If the touch voltage does not become zero, there is a slag at that position. Judgment, the control panel 1 outputs an ascending drive command of the welding torch 3 to the torch vertical drive device 14 to raise the entire welding torch 3 to its original starting height (separate the base material 7 by the required amount Δh), In addition, a forward drive command for the welding torch 3 is output from the control panel 1 to the torch front-rear drive unit 15, and the entire welding torch 3 is advanced by a required amount (moved by the required amount along the base material 7), and the touch voltage becomes zero The same operation is repeated until the touch voltage becomes zero, and at the position where the touch voltage becomes zero, the control panel 1 outputs a drive command for raising the welding torch 3 to the torch vertical drive device 14 to raise the entire welding torch 3 to the original height. Sa (Is moved away by a required amount Δh from the base material 7), lies in that to perform the arc start similarly to the conventional after opening the touch power circuit off switch 20.

Next, the operation of the illustrated example will be described.

For example, after the automatic welding of the first layer is performed, when the arc is again to be ignited at the end position or the first starting point in order to perform the automatic welding of the next layer, the torch switch 5 is turned on. First, a touch voltage application command is output from the control panel 1 to the touch power supply 18, a circuit close command is output to the touch power circuit open / close switch 20, and a touch voltage is applied between the welding wire 6 and the base material 7. With the voltage applied,
A lowering drive command for the welding torch 3 is output from the control panel 1 to the torch up / down driving device 14, so that the entire welding torch 3 has a required amount Δ
After moving down by h (close to the base material 7), the tip of the welding wire 6 comes into contact with the base material 7.

At this time, the touch voltage is monitored by the touch voltage detector 19, and if the touch voltage does not become zero, it is determined that there is a slag at that position, and the torch up / down control is performed from the control panel 1. An ascending drive command for the welding torch 3 is output to the driving device 14, the entire welding torch 3 rises to the original starting height (separated from the base material 7 by the required amount Δh), and the torch back-and-forth driving device 15 from the control panel 1. A forward drive command of the welding torch 3 is output, the entire welding torch 3 advances by a required amount (moves by the required amount along the base material 7), and the same operation is repeated until the touch voltage becomes zero. At the position where the touch voltage becomes zero, the control panel 1 outputs an ascending drive command for the welding torch 3 to the torch vertical driving device 14, and the entire welding torch 3 rises to its original height (the required amount Δh from the base metal 7). Only), an open circuit command is output to the touch power supply circuit open / close switch 20, and an arc start is performed as in the conventional case.

Generally, the slag does not cover the entire surface of the weld bead 13 but is scattered at a certain interval. Therefore, even if the slag exists at the end position or the first starting point, As described above, if the position of the welding torch 3 is moved by a required amount along the base material 7, it reaches a position where no slag exists, and if an arc start is performed at that position, an arc is reliably generated. I will be.

As a result, it is no longer necessary for the operator to enter the operating area of the automatic welding device in order to remove the slag adhered to the surface of the welding bead 13 using a wire brush or the like, and the automatic welding is interrupted. However, work efficiency is also improved.

Thus, the arc can be reliably generated without interrupting the automatic welding, and the working efficiency can be improved.

Incidentally, the automatic welding start control method of the present invention is not limited to the above-described illustrated example, and various changes can be made without departing from the scope of the present invention.

[0026]

As described above, according to the automatic welding start control method of the present invention, it is possible to reliably generate an arc without interrupting the automatic welding and to improve the working efficiency. Excellent effects can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an example of an embodiment of the present invention.

FIG. 2 is a flowchart of an example of an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a conventional example.

FIG. 4 is a flowchart of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control panel 2 Welding machine 3 Welding torch 5 Torch switch 6 Welding wire 7 Base material 8 Welding power supply 13 Welding bead 14 Torch up-down drive 15 Torch up-down drive 16 Torch up-down movement commander 17 Torch back-and-forth movement commander 18 Touch power 19 Touch voltage detector 20 Touch power circuit open / close switch

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Takashi Miyazaki 5292 Aioi, Aioi-shi, Hyogo Pref. Inside the Aioi Plant of Ishikawajima Harima Heavy Industries, Ltd. (72) Inventor Masahiko Kinji 5292 Aioi, Aioi-shi, Hyogo Prefecture (72) Inventor Yoshiyuki Shimada 5292 Aioi, Aioi-shi, Hyogo F-term (reference) 4E082 EA02 EB01 EC01

Claims (1)

[Claims] 1. A start control method for automatic welding in which a torch switch is turned on, a welding current value is set, a welding wire is sent out, and a tip of the welding wire is brought into contact with a base material to perform an arc start. Before touching, the touch power supply circuit is closed and the touch voltage is applied between the welding wire and the base material.Then, the entire welding torch is brought close to the base material, and the tip of the welding wire is brought into contact with the base material. If the touch voltage does not become zero, the entire welding torch is separated from the base material by a required amount and moved along the base material by a required amount, and the same operation is performed until the touch voltage becomes zero. Automatic operation characterized by repeating the operation, separating the entire welding torch from the base material by the required amount at the position where the touch voltage becomes zero, opening the touch power supply circuit, and performing arc start Start control method of contact.