JPS63220979A - Tig welding method - Google Patents

Abstract

PURPOSE:To realize the continuous TIG welding for many hours by detecting the consumption of an electrode attaining the prescribed quantity to interrupt the welding and projecting the electrode by the fixed quantity by a driving source and fixing the electrode on a torch by a clamp means to resume the welding. CONSTITUTION:The torch 2 for the TIG welding is positioned on a member 5 to be welded by a robot 3 for welding to weld a weld line continuously. When the electrode 4 is consumed during welding and the arc voltage exceeds a prescribed range, the position of the robot 3 is corrected to maintain the arc voltage constant. Further, when the consumption of the electrode 4 attains the prescribed quantity, a controller 8 commands to interrupt the welding and moves the torch 2 to the position of an electrode projecting device 7. The device 7 projects the electrode 4 in an unclamped state via a piston rod 42 and a pressing-out member 15 by a cylinder 41. After this, the electrode 4 is again fixed on the torch 2 by the clamp means to resume the welding. By this method, the electrode position is corrected automatically during welding to perform continuous TIG welding.

Description

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

In the prior art 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 TtG 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 the conventional technology, even if a welding robot is used, there are limits to continuous automation of welding, and the work efficiency is also limited, because the electrode position adjustment and replacement cannot be performed automatically. bad.

OBJECTS OF THE INVENTION Therefore, it is an object of the present invention to automatically correct the electrode position in a T I GR welding torch, allowing long-term continuous use and increasing 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 forward and backward, and fixes it by a clamping means, and also detects consumption of the electrode during welding and detects when the consumption exceeds a certain tolerance value. When this occurs, the welding is temporarily interrupted, the electrode is pushed out by a predetermined amount, and the electrode is fixed again using the clamping means.
I'm trying to resume welding. Clamping and unclamping of the electrode, measurement of the amount of consumption, adjustment of the amount of protrusion of the electrode, etc. are automatically performed by the welding robot, welding machine, and their control devices.

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

Configuration of welding equipment.

First, FIG. 1 shows a welding apparatus l for carrying out the method of the 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 movement in the welding direction to the TIG welding torch 2,
A welding machine 6 for generating an arc between the electrode 4 of the TIG welding torch 2 and the welding material 5 is installed at a second origin position away from the first origin of the welding robot 3, and the electrode 4 is placed at a predetermined position. The welding robot 3 is assembled with an electrode sticking device 7 for ejecting a certain amount, and a control device 8 for controlling the movements of the welding robot 3 and the electrode ejecting device 7 by using signals from the welding a6 as human power.

Next, FIGS. 2 and 3 show a specific configuration of the TIG welding torch 2. As shown in FIG. This TIG welding torch 2 is assembled with a main body 10, and a part of it is attached to the arm 90 of the welding robot 3 by a part 11 at an appropriate inclination. The main body 1O has a storage hole 12 with a round cross section in the vertical direction, and is provided with a guide 13 and a tapered nozzle 14 fixed by screwing at the upper and lower ends thereof. The guide 13 is hollow and holds the push-out member 15 slidably in the axial direction at its center in the longitudinal direction, with one end protruding outside and housed in a state where it cannot be removed. Further, the main body 10 concentrically holds the rod-shaped electrode 4 inside the storage hole 12 using a hollow adapter 16, a holder 17 having a bisected collet claw 30, and a tungsten material. The above adapter 16
is fixed inside the storage hole 12 by a NAND 18, and forms a spiral cooling groove 19 at the part where it fits into the storage hole 12, and each groove end has a groove for allowing the cooling liquid 20 to pass through. , the passage 21. on the main body 10 side.
The port 22 is connected to an inlet port 23 and an outlet port 24, respectively. Further, the holder 17 has a main body l.
An inclined through hole 26 with a square cross section is formed at a position intersecting with the guide hole 25 on the O side, and this portion forms a sliding pair with a clamp piece 27 having the same inclination as a clamping means. The electrodes 4 intersect inside the elongated hole 28 in the direction of movement of the clamp piece 27, and are in a relationship where the rear end portion contacts the push-out member 15, and the tip portion contacts the holder 17.
The collet protrudes from the opening surface of the nozzle 14 by a predetermined amount while being held by the collet pawl 30 . This holder 17
The inside forms an inert gas passage 29 together with the communication hole 31 of the nuff 1B and the upper space of the storage hole 12, which reaches the connection boat 33 of the inert gas 32, and also the gap between the collet claws 30. From there, it reaches the inside of the nozzle 14 via the tip hole 34 of the holder 17.

On the other hand, the clamp piece 27 is formed integrally with, for example, a piston rod 36 of a piston 35 as a clamp original means. This piston 35 is held slidably in a direction intersecting the electrode 4 inside an air cylinder 37 formed by a part of the main body 10 . Note that the open end of this air cylinder 37 is closed by a plug 38. Of course, the driving air 45 can be taken in and out of the air cylinder 37 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. The cylinder 4 and the electrode receiver 43 are both fixed to a frame 44 or the like in a positioned manner.

The TIG welding method control device 8 controls TIG in advance according to the welding position of the welding material 5.
Data necessary for controlling the posture and movement path of the IG welding torch 2 is stored, and by sequentially reading this data, the movement of the welding robot 3 is controlled for each x-y-z axis. On the other hand, the welding machine 6 is used for TIG welding.
A predetermined welding voltage is applied between the electrode 4 and the welding material 5, an arc is generated between them, and the welding material 5 or filler metal is adjusted to a state in which it can be melted.

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 comes into contact with the tapered inner circumferential surface of the tip hole 34 at its tip, deforms in the direction of diameter reduction, and clamps the electrode 4 with an appropriate protrusion amount.

At the first stage of welding, welding m6 applies an appropriate welding voltage to electrode 4. Therefore, the control device 8 confirms the appropriate welding voltage from the welding machine 6, and then drives the welding robot 3 to perform TIG? Pj welding torch Guides the welding torch 2 from the first origin position to the welding position of the welding material 5. At this time, the TIG welding torch 2 faces the welding surface of the welding material 5 with an appropriate distance therebetween. After that, the control device 8 executes the welding program and moves the TIG welding torch 2 to the welding line of the welding material 5 based on the movement path of the TIG welding torch 2 and the data on its posture control stored in advance. By moving the electrode 4 along the welding material 5, continuous welding is performed and the welding voltage, that is, the electrode 4 and the welding material 5 are constantly maintained.
We will continuously measure the arc voltage. During this time, the inert gas 32 is continuously fed from the connection boat 33 to the inert gas passage 29, that is, between the electrode 4 and the holder 17.
The inert gas 32 passes through the gap between the welding material 5 and the inside of the tip hole 34 and the nozzle 14, and is injected at the welding position intermittently.In this way, the welding position of the welding material 5 is surrounded by the inert gas 32 during welding. Therefore, the metal of the welding material 5 does not combine with oxygen or nitrogen in the air, and is welded without the risk of rust.

If the arc voltage becomes higher than a predetermined range during welding, 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, and temporarily stops welding. After the interruption, the program moves to the electrode adjustment program, and by driving the welding robot 3, the TIG welding
is moved to the second origin position, and then the piston 35 is moved back in the direction of arrow B to pull up the holder 17 in the unclamping direction, and by opening the collet pawl 30, the electrode 4 is brought into the unclamped state. After preparing for the electrode sticking operation, the electrode sticking 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 out 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, thereby unloading. The clamped electrode 4 is made to protrude and its tip is pressed 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 protruding operation of the electrode 4 is completed, the control device 8 moves the piston 35 again in the direction of arrow A to clamp the electrode 4, and after confirming this, starts the remaining welding program again. We will continue to implement it.

Modified Examples of the Invention In the above embodiment, the welding robot 3 is of the orthogonal coordinate type, but the type of the robot is not limited to this, and may be, for example, a multi-joint type, or a robot with three or more axes. 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.

In addition, the feeding amount of the electrode 4 is determined by the nozzle 14 as in the embodiment.
This can be realized not only by the distance between the electrode receiver 43 but also 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 welding amount. and,
This 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 the 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 toe 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 similar to the knock method of a mechanical pencil, in which the movement in the ejecting direction is converted by a cam mechanism, and a fixed amount is pushed out in one pushing operation. It's okay.

In that case, the amount of extrusion can be regulated by the number of knocks. Of course, the means for knocking does not need to be attached to the second origin or the like;
It is sufficient if it is attached directly to the upper part of the

Effects of the Invention In the present invention, the consumption of the electrode during welding is indirectly detected by changes in the welding voltage, etc., and the protrusion amount of the electrode is automatically adjusted by the drive source as necessary. Artificial adjustment of the protrusion amount is not required, and even in a continuous control process, welding with good reproducibility can be performed efficiently and continuously.

[Brief explanation of the drawing]

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...'r IG 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.
...Collet claw, 37..Air cylinder, 41..Cylinder, 43..Electrode holder. Patent applicant Sankyo Seiki Seisakusho Co., Ltd.
Attorney Kunio Nakagawa, Patent Attorney Figure 2 Figure 4 Procedural Report (spontaneous) August 21, 1985 Director General of the Patent Office Kunio Ogawa 1, Indication of the Case ■Co Patent Application No. 1988 049910 No. 2, Title of the invention TIG welding method 3, Relationship to the case of the person making the amendment Patent applicant address 5329 Shimosuwa-cho, Suwa-gun, Nagano Prefecture Name
(223) Sankyo Seiki Co., Ltd. Representative Yama 1
) 6-4, Agent ■ 160 Name (8377) Patent attorney Kunio Dochu 5, Date of amendment order None 6, Subject of amendment Detailed explanation of the invention in the specification column 7,
Contents of the amendment (1) "Divide into two" on page 5, line 5 of the specification is corrected to "divide into two or into four." (2) On page 9, lines 9 and 10 of the specification, "during welding...if it becomes large" is replaced with "during welding, if the arc voltage becomes larger than a predetermined range due to electrode wear, the robot's position is corrected to keep the arc voltage constant.

Claims (1)

[Claims] The electrode is supported on a TIG welding torch so that it can move forward and backward, and welding is performed by fixing the electrode with a clamping means. During welding, when it is detected that the electrode wear has reached a predetermined amount, welding is interrupted, and the welding is stopped using a drive source. Take out a fixed amount of the electrode and use a clamp to hold the electrode at T.
A TIG welding method characterized in that the welding is restarted by fixing it to an IG welding torch.