JPH0372387B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a TIG welding method, and particularly to a means for regulating the amount of protrusion of a tungsten electrode to a predetermined amount during the welding process.

Prior Art In the TIG welding method, a rod-shaped electrode made of tungsten is used. Originally, this rod-shaped electrode should not wear out, but when used for a long time, it forms a rounded spherical surface at the tip. As a result, the arc voltage changes and the finish of the welded part becomes uneven.

For this reason, in automatic TIG welding, the arc voltage is measured, and the relative distance between the TIG welding torch and the welding material can be adjusted by moving a slide base or the like based on fluctuations in the voltage. It is being said. However, such adjustment means can only be used within the adjustment range of the arc voltage, and when the arc voltage falls outside of the adjustment range, manual electrode replacement is required.

Therefore, according to conventional technology, it is not possible to automatically adjust the electrode position and replace it, so even if a welding robot is used, there is a limit to continuous automation of welding, and the process is difficult. It's also inefficient.

OBJECTIVES OF THE INVENTION Therefore, an object of the present invention is to automatically correct the electrode position in a TIG welding torch to enable long-term continuous use and to increase the efficiency of automatic welding.

SUMMARY OF THE INVENTION Therefore, the present invention supports an electrode in a TIG welding torch so that it can move back and forth, and fixes it by a clamping means, and also detects wear of the electrode during welding.
When the amount of wear exceeds a certain tolerance, welding is temporarily interrupted, the electrode is pushed out by a predetermined amount, and after being fixed again by the clamping means, welding is restarted. Clamping and unclamping the electrode, measuring the amount of wear, and adjusting the amount of protrusion of the electrode are performed using a welding robot, welding machine,
and automatically by their control devices.

Therefore, according to the present invention, the amount of protrusion of the electrode can always be maintained within a predetermined range, and as a result, stable
TIG welding is now possible, and the protruding amount of the welding rod is automatically adjusted, allowing a series of welding operations to proceed efficiently and automatically.

Configuration of Welding Apparatus First, FIG. 1 shows a welding apparatus 1 for carrying out the method of the present invention.

This welding device 1 is electrically connected to, for example, an orthogonal coordinate type welding robot 3 and the TIG welding torch 2 in order to give motion to the TIG welding torch 2 in the welding method. A welding machine 6 is provided to generate an arc between the electrode 4 and the welding material 5, and a welding robot 3 is provided at a second origin position away from the first origin, and is used to project the electrode 4 by a predetermined amount. It is assembled by an electrode sticking device 7 and a control device 8 for controlling the movements of the welding robot 3 and the electrode sticking device 7 by inputting signals from the welding machine 6.

Next, FIGS. 2 and 3 show a specific configuration of the TIG welding torch 2. As shown in FIG. This T.I.G.
The welding torch 2 is assembled by a main body 10, and is attached to the arm 9 of the welding robot 3 at an appropriate inclination by a part of the attachment part 11. The main body 10 forms a storage hole 12 with a round cross section in the vertical direction, and is provided with a guide 13 fixed by screwing and a tapered nozzle 14 at the upper and lower ends thereof. The guide 13 has a hollow shape, holds the extrusion member 15 slidably in the axial direction at its longitudinal center position, and has one end thereof protruding outside.
It is stored in a way that prevents it from falling out. In addition, the main body 1
0 is a hollow adapter 1 inside the storage hole 12
6. A holder 17 having, for example, a halved or quartered collector claw 30 and a rod-shaped electrode 4 made of tungsten are held concentrically. The adapter 16 is connected to the storage hole 1 by a nut 18.
2, and a spiral cooling groove 19 is formed at the part that fits into the storage hole 12, and each groove end is connected to a passage on the main body 10 side in order to allow the cooling liquid 20 to pass through. It is connected to an inlet port 23 and an outlet port 24 via ports 21 and 22, respectively. Further, the holder 17 is
An inclined through hole 26 with a square cross section is formed at a position intersecting with the guide hole 25 on the main body 10 side, and a clamp piece 27 of the same inclination is used as a clamping means at this part.
In contrast, it forms a sliding counterpart. The electrodes 4 intersect inside the elongated hole 28 in the direction of movement of the clamp piece 27, are in contact with the push-out member 15 at the rear end, and are held by the collect claw 30 of the holder 17 at the tip end. So, nozzle 14
protrudes from the opening surface by a predetermined amount. The inside of this holder 17 includes a communication hole 31 of the nut 18,
Together with the upper space of the storage hole 12, an inert gas passage 29 is formed, which reaches a connection port 33 for the inert gas 32, and from the gap between the collet claws 30, through the tip hole 34 of the holder 17, and the nozzle 1.
It has reached the inside of 4.

On the other hand, the clamp piece 27 is used as a clamp operating means, for example, when the piston rod 36 of the piston 35 is used.
is integrally formed with. This piston 35
is an air cylinder 3 formed from a part of the main body 10
It is held inside the electrode 7 so as to be slidable in a direction crossing the electrode 4. Note that this air cylinder 37
The open end of is closed by a stopper 38. Of course, the inside of this air cylinder 37 is designed such that driving air 45 can be taken in and out through two ports 39 and 40.

Next, as shown in FIG. 4, the electrode sticking device 7 is provided at a second origin within the motion range of the welding robot 3, which is located away from the first origin of the welding robot 3. According to the example, the drive source for protruding the electrode is constituted by a cylinder 41 and an electrode receiver 43 provided at a position facing the piston rod 42 of the cylinder 41. Both the cylinder 41 and the electrode receiver 43 are fixed to a frame 44 or the like in a positioned manner.

TIG welding method The control device 8 stores in advance data necessary for posture control and movement path control of the TIG welding torch 2 according to the welding position of the welding material 5, and by sequentially reading this data, Welding robot 3
The movement of is controlled for each X-Y-Z axis. on the other hand,
The welding machine 6 applies a predetermined welding voltage between the electrode 4 of the TIG welding torch 2 and the welding material 5, generates an arc between them, and brings the welding material 5 or filler metal into a state where it can be melted. be adjusted.

First, during welding, the piston 35 moves forward in the direction of arrow A under the pressure of the driving air 45, so the clamp piece 27 presses the holder 17 in a downward direction. As a result, the collet pawl 30 has a distal end portion that is aligned with the distal end hole 34.
The electrode 4 is in contact with the tapered inner circumferential surface of the electrode 4 and deformed in the diametrical direction, thereby clamping the electrode 4 with an appropriate protrusion amount.

At the initial stage of welding, the welding machine 6 applies an appropriate welding voltage to the electrode 4. Therefore, after confirming the appropriate welding voltage from the welding machine 6, the control device 8 drives the welding robot 3 to move the TIG welding torch 2 from the first origin position in the standby position to the welding position of the welding material 5. invite. At this time, the TIG welding torch 2 faces the welding surface of the welding material 5 with an appropriate distance therebetween. After this, the control device 8
TIG that executes welding programs and stores them in advance
Based on the motion path of the welding torch 2 and its posture control data, the TIG welding torch 2 is moved to the welding material 5.
By moving the electrode along the welding line, welding is performed continuously and the welding voltage, that is, the arc voltage between the electrode 4 and the welding material 5 is continuously measured. During this time, the inert gas 32 is continuously fed from the connection port 33 to the inert gas passage 29, that is, the gap between the electrode 4 and the holder 17.
Furthermore, it passes through the side end hole 34 and the inside of the nozzle 14 and is continuously sprayed at the welding position. In this way, during welding, the welding position of the welding material 5 is surrounded by the inert gas 32, so the metal of the welding material 5 does not combine with oxygen and nitrogen in the air, causing rust etc. be welded without fear of

During welding, if the arc voltage exceeds a predetermined range due to electrode wear, the position of the robot is corrected to keep the arc voltage constant.

If this process is repeated and the electrode becomes worn out,
The electrode light end is retracted more than the nozzle 14,
The nozzle 14 hits the welding material 5, making it impossible to keep the arc voltage constant. Therefore, the control device 8 determines that the tip of the electrode 4 is worn out, issues a command to the welding machine 6 to interrupt welding, temporarily interrupts the welding, moves to the electrode adjustment program, and starts the welding robot 3. By driving the TIG welding torch 2 to the second origin position, and then moving the piston 35 back in the direction of arrow B,
By pulling up the holder 17 in the unclamping direction and opening the collector claw 30, the electrode 4 is brought into an unclamped state in preparation for an operation for pushing out the electrode 4, and then the electrode pushing out device 7 is operated. When the TIG welding torch 2 is guided to the second origin position, the opening surface of the nozzle 14 of the TIG welding torch 2 and the opposing surface of the electrode receiver 43 are opposed to each other with a fixed distance therebetween. Therefore, when the electrode pushing device 7 receives an operation command from the control device 8, it operates the cylinder 41, advances its piston rod 42, and pushes the pushing member 15 into the guide 13 to unclamp it. state electrode 4
protrude and press its tip against the electrode receiver 43. As a result, the electrode 4 protrudes from the opening surface of the nozzle 14 by a predetermined amount. In this way, when the operation of pushing out the electrode 4 is completed,
The control device 8 moves the piston 35 in the direction of the arrow A again to put the electrode 4 in the clamped state, and after confirming this, executes the remaining welding program again.

Modifications of the Invention In the above embodiment, the welding robot 3 is an orthogonal coordinate type as an example, but the type of the robot is not limited to this. A control method may also be used. Further, the clamping means for the electrode 4 and the driving source for protruding the electrode 4 are not limited to the air cylinder 37 and the cylinder 41, but may be other actuators.

Further, the feed amount of the electrode 4 is not limited to the distance between the nozzle 14 and the electrode receiver 43 as in the embodiment, but can also be realized by proportional control. For example, when the TIG automatic voltage regulator is installed inside the welding machine 6, its output voltage is converted into a proportional analog amount of welding. The analog ejecting signal may be converted into the amount of rotation of a feed motor, for example, and the electrode 4 may be moved in the ejecting direction using a feed screw mechanism or the like according to this amount of rotation. . In this case, the amount of movement of the electrode 4 is directly related to the output voltage, so the electrode receiver 43 becomes unnecessary.

Further, in the TIG welding torch 2, when the electrode 4 is in an unclamped state, a pressing force is applied from the outside to push the electrode 4 out. However, this control for ejecting is of a type that converts the movement in the ejecting direction using a cam mechanism and pushes out a fixed amount in one extrusion operation, like the knock method of a sharp pencil. It may be. In that case, the amount of extrusion can be regulated by the number of notches. Of course, the means for the notch does not need to be attached to the second origin or the like, and it is sufficient if it is attached directly to the upper part of the main body 10.

Effects of the Invention In the present invention, the state of electrode wear during welding is indirectly measured by measuring the arc (welding) voltage,
When the relative position correction limit between the electrode and welding material is exceeded, the clamping means of the TIG welding torch unclamps the electrode, the electrode sticking device automatically pushes out the electrode by a predetermined amount, and then Since the clamping means clamps the electrode after protruding, there is no need to artificially adjust the protruding amount of the electrode, and even in continuous control processes, welding with good reproducibility can be performed efficiently and continuously. I can do it.

[Brief explanation of drawings]

FIG. 1 is a side view of the welding device, FIG. 2 is a plan view of the TIG welding torch, FIG. 3 is a vertical sectional view of the TIG welding torch, and FIG. 4 is a side view of the electrode sticking device. 1... Welding equipment, 2... TIG welding torch, 3
... Welding robot, 4 ... Electrode, 5 ... Welding material, 6 ... Welding machine, 7 ... Electrode sticking device, 8
...Control device, 10...Main body, 14...Nozzle,
15... Extrusion member, 17... Holder, 29
...Inert gas passage, 30...Collection claw, 37
...Air cylinder, 41...Cylinder, 43...
Electrode receiver.

Claims (1)

[Claims] 1. A TIG welding torch that supports an electrode so that it can move forward and backward and that the electrode is fixed by a clamping means, a welding robot that provides movement in the welding direction to the TIG welding torch, and a TIG welding torch that A welding machine that is connected to generate an arc between the electrode and welding material, an electrode sticking device that sticks out a predetermined amount of the electrode supported by a TIG welding torch, a welding robot, a welding machine, and an electrode. In a welding device consisting of a control device that controls the operation of the welding device, the control device detects the wear of the electrode during welding by using arc voltage, and when the electrode is worn out by a predetermined amount beyond the limit of position correction, the control device After interrupting the operation and releasing the electrode using the clamping means, the released electrode is pushed out by a predetermined amount using the electrode sticking device, the electrode is fixed to the TIG welding torch using the clamping means, and then welding is automatically resumed. A TIG welding method characterized by: