Teaching tool for welding torch, welding torch having same, and method for teaching welding path of welding torch using same

Abstract

The invention relates to a teaching tool (1) for a welding torch (10), in particular a plasma welding torch (15), having a gas nozzle (11) with an opening (12) for a non-consumable electrode (13) with a tip (14), the teaching tool (1) being used in teaching a welding path (X) along a workpiece (W) of the welding torch (10) attached to a welding robot (16), the invention relates to a teaching tool (1) comprising a substantially circularly symmetrical body (2) having a free end (3), to a welding torch (10) having such a teaching tool (1) and to a method for teaching a welding path (X) of a welding torch (10) using such a teaching tool (1), in which the body (2) is formed from an elastic material. The teaching tool (1) is characterized in that the body (2) comprises a connecting piece (4) arranged opposite the free end (3), the connecting piece (4) being formed by a truncated cone (5) for tool-free fastening in an opening (12) of a gas nozzle (11) of a welding torch (10).

Description

Technical Field

[0001] The invention relates to a teaching tool for a welding torch, in particular a plasma welding torch, the welding torch having a gas nozzle with an opening for a non-melting electrode with a top end, the teaching tool being used when teaching a welding path along a workpiece attached to the welding torch of a welding robot, the teaching tool comprising a substantially circularly symmetrical body with a free end, wherein the body is formed of an elastic material.

[0002] Furthermore, the invention relates to a welding torch for a non-consumable electrode, in particular a plasma welding torch, the welding torch having a gas nozzle with an opening for the non-consumable electrode and a device for mounting on a welding robot.

[0003] Finally, the present invention relates to a method for teaching a welding path of a welding torch attached to a welding robot using the above-mentioned teaching tool. Background Art

[0004] In robotic welding, which is particularly used for welding larger workpieces, it is extremely difficult for the operator to teach welding because the field of view of the welding nozzle is completely obstructed by the gas nozzle. Therefore, it is impossible to judge whether the welding electrode is pointing to the weld seam or the arc position and whether the distance between the nozzle and the workpiece is reasonable.

[0005] The present invention relates primarily, but not exclusively, to plasma welding, in which an arc is formed between a non-melting electrode and a workpiece. Plasma torches are relatively large, so the visibility of the plasma gas nozzle during the teaching process is partially limited or even blocked, making the teaching process very difficult. If the field of view of the torch is disturbed or even blocked during the teaching process, it is impossible to tell whether the electrode is guided at the desired position on the welding path and whether the distance between the electrode or the gas nozzle and the workpiece is appropriate. If the teaching process is carried out using a conventional torch with a non-melting electrode, there is also a risk of damaging the workpiece or parts of the torch, such as the gas nozzle or the electrode.

[0006] It is known in the prior art to use a special welding torch during the teaching process. For example, JPH0726061U describes a dummy contact tip that can be connected to the welding torch by screws. The dummy contact tip is made of an elastic material and its dimensions correspond to the dimensions of the real electrode.

[0007] CN207952899U describes a teaching tool for a welding torch according to the prior art, wherein the connection to the welding torch or the welding torch robot is not described in detail.

[0008] CN205497532U discloses another teaching tool for an industrial robot.

[0009] Another teaching tool for a welding robot for a MIG / MAG welding process is shown in JPH0726062U. The teaching tool is detachably fastened to the welding torch and contains a compression spring or a rubber leaf spring.

[0010] Known elements of this type for the teaching process of a welding torch are usually of complex design or are complex to mount or remove from the welding torch. Summary of the invention

[0011] The object of the present invention is therefore to produce a teaching tool for a welding torch, in particular a plasma welding torch, with a non-consumable electrode, which can be mounted on and removed from the welding torch particularly easily and quickly and which has a particularly simple and cost-effective design. Another object of the present invention is to provide a welding torch, in particular a plasma welding torch, for a non-consumable electrode, and a method for teaching a welding path for welding using such a welding torch, wherein in operation teaching can be carried out easily, safely and without the risk of damaging the workpiece or parts of the welding torch. The disadvantages of the known devices and methods are avoided or at least reduced.

[0012] The object of the present invention is solved on the one hand by a teaching tool as described above, wherein the body comprises a connection piece arranged opposite the free end, the connection piece being formed by a truncated cone, the truncated cone being used for tool-free fastening in the opening of the gas nozzle of the welding torch. The teaching tool consists of an elastic material, which on the one hand can prevent damage to the workpiece during the teaching process. On the other hand, the teaching tool can thus be attached to the welding torch and removed again particularly quickly and easily. The elastic material and the corresponding dimensions of the teaching tool allow the teaching tool to be retained in the gas nozzle by friction and no fastening elements and tools are required for assembly and disassembly. The connection piece of the teaching tool is formed by a truncated cone. This design helps to place the teaching tool in the opening of the gas nozzle of the welding torch and to retain the teaching tool by friction. The non-melting electrode of the welding torch does not have to be removed during the switching of the teaching process, but can also be simply moved inside the gas nozzle so that space for the teaching tool is created at the opening of the gas nozzle. The teaching tool is also particularly simple and therefore inexpensive to manufacture.

[0013] Preferably, the average diameter of the connection piece of the truncated cone is slightly larger than the diameter of the opening of the gas nozzle of the welding torch. Such a configuration dimension ensures that the teaching tool is firmly held in the opening of the gas nozzle by friction. Preferably, the average diameter of the truncated cone is 4% to 8% larger than the diameter of the opening of the gas nozzle of the welding torch.

[0014] If a flange with a larger diameter than the connecting piece is arranged between the connecting piece and the free end of the body of the teaching tool, it can ensure that the teaching tool is attached to the gas nozzle in the desired position. On the one hand, the flange prevents the teaching tool from tilting relative to the gas nozzle and, on the other hand, always ensures that the tip of the teaching tool is at a defined distance from the end of the gas nozzle. This ensures a suitable Tool Center Point (TCP) during the teaching process.

[0015] In particular, the body of the teaching tool is manufactured in one piece. This allows a very simple and cost-effective production of the teaching tool.

[0016] If the elastic material of the body of the teaching tool contains, in particular, 30 to 40 percent by volume of graphite carbon, the wear resistance of the material and thus its service life can be increased. For teaching tools made of ordinary silicone rubber, the wear resistance will be seriously reduced after 4 uses. Adding some graphite carbon to the silicone rubber matrix increases the service life of the teaching tool by 10 times or more. The graphite carbon can be mixed into the silicone rubber matrix in the form of a powder and / or in the form of a powder compound.

[0017] Advantageously, the elastic material of the body has a Shore hardness of 40 to 50 Shore A, in particular 45 to 48 Shore A. Such hardness values ​​are advantageous for the use of the teaching tool and for retention in the opening of the gas nozzle.

[0018] According to another feature of the invention, the elastic material of the body has a modulus of elasticity ranging from 7.8 to 12 MPa, in particular from 9.8 to 10 MPa.

[0019] A suitable material for the body of the teaching tool is rubber or a rubber compound, in particular silicone rubber. Such a material having the above characteristics is used to match friction, hardness, wear resistance and elasticity. Silicone rubber shows an ideal performance of elasticity and heat resistance even at temperatures up to 150°C and higher. In addition, when the elastic hardness is 40 Shore A, silicone rubber has a Shore hardness of 10-80 degrees and an elastic modulus of 8MPa, so that a slight elastic deformation can generate sufficient extrusion force to obtain the friction force between the teaching tool and the metal surface of the gas nozzle. The friction force is calculated by f=μ*N, where f is the friction force, μ is the friction coefficient (0.25 between copper and silicone rubber) and N is the normal pressure. Therefore, the friction force f is proportional to the normal pressure N and the elastic deformation. In this case, a deformation of the silicone rubber of 0.2mm to 0.4mm is sufficient to generate the friction force f to overcome gravity.

[0020] If fluorescent particles are mixed into the elastic material or the body is at least partially surrounded by a fluorescent skin or coating, the visibility of the teaching tool during the teaching process may be improved. The fluorescent teaching tool may be an advantage for the operator, especially in a dark operating environment.

[0021] According to another feature of the invention, the free end of the body of the teaching tool has a rounded end, in particular with a diameter of 0.4 to 0.6 mm. Such a radius has proven to be suitable in practice in terms of the wear resistance of the tip.

[0022] As mentioned above, the object of the invention is also solved by a welding torch, in particular a plasma welding torch, for a non-melting electrode, having a gas nozzle and a device mounted on a welding robot, wherein the gas nozzle has an opening for the non-melting electrode. The above-mentioned teaching tool is provided and is fastened in the opening of the gas nozzle. Reference is made to the above description of the teaching tool for the advantages that can be obtained thereby.

[0023] Finally, the object of the invention is also solved by a method as described above for teaching a welding path of a welding torch attached to a welding robot using the above-mentioned teaching tool, wherein the welding torch passes through the desired welding path, and the above-mentioned teaching tool is fastened to the welding torch. For the advantages that can be achieved by this method, reference is made to the description of the above-mentioned teaching tool.

[0024] Advantageously, contact of the teaching tool with the workpiece is detected and the teaching of the welding path is corrected accordingly.

[0025] The contact of the teaching tool with the workpiece can be detected by the force detected at the welding robot or by the electrical measurement voltage at the teaching tool. The force acting on the teaching tool can be detected, for example, by a force measuring device usually on the robot. In the latter case, a certain conductivity of the teaching tool is required, which can be achieved, for example, by adding conductive particles (for example, graphite, nickel-plated copper powder and / or silver powder) to the elastic material of the body of the teaching tool or by wrapping the body of the teaching tool with a conductive material. In another embodiment, the body is at least partially surrounded by a conductive coating. The conductive coating can be applied by brushing, spraying, dipping or other coating methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention is explained in more detail with reference to the accompanying drawings.

[0027] Figure 1 A plasma welding torch which can be mounted on a welding robot is shown in a simplified representation according to the prior art;

[0028] Figure 2A first embodiment of a teaching tool is shown in detail;

[0029] Figure 3 A second embodiment of the teaching tool is shown;

[0030] Figure 4 Another teaching tool with a cylindrical connection is shown, which does not fall within the scope of the present invention and has a rounded end at the free end;

[0031] Figure 5 Another embodiment of a teaching tool having a fluorescent surface layer is shown;

[0032] Figure 6 A cross-sectional view of another embodiment of a teaching tool is shown;

[0033] Figure 7 A cross-sectional view of another embodiment of a teaching tool is shown;

[0034] Figure 8 It shows that according to Figure 3 A partial cross-sectional view of a gas nozzle of a teaching tool according to the present invention according to a second embodiment shown;

[0035] Fig. 9 It shows that according to Figure 3 A partial cross-sectional view of another gas nozzle of the teaching tool according to the present invention according to the second embodiment shown;

[0036] Fig.10 It shows that according to Figure 7 The illustrated embodiment is a partial cross-sectional view of another gas nozzle of a teaching tool according to the present invention. DETAILED DESCRIPTION

[0037] Figure 1 A welding torch 10 according to the prior art is shown in a simplified representation, in particular a plasma welding torch 15 with a device 17 for mounting on a welding robot 16 (not shown). The plasma welding torch 15 comprises a gas nozzle 11 with an opening 12 and a non-melting electrode 13, which is usually made of tungsten. Depending on the torch design, the non-melting electrode 13 may or may not protrude. Various cables and cooling lines (not shown) are fed to the plasma welding torch 15 via a hose package S. In the above figures, the plasma welding torch 15 is fed with a filler material Z to the welding point P, with which the welding of the workpiece W along the welding path X is carried out. Before carrying out the welding process, a so-called teaching process is usually carried out, in which the movements of the welding robot 16 are determined so that the subsequent welding process is carried out along the desired welding path X. During the teaching process, if the distance between the plasma welding torch 15 and the workpiece W is selected to be too small, there is a risk of damaging the workpiece W or parts of the plasma welding torch 15, in particular the non-melting electrode 13. This problem is eliminated by the present invention.

[0038] Figure 2 A first embodiment of a teach tool 1 is shown in detail. The teach tool 1 comprises a substantially circularly symmetrical body 2 with a free end 3, wherein the body 2 is formed from an elastic material, such as rubber or a rubber compound, in particular silicone rubber. In addition, the body 2 of the teach tool 1 comprises a connecting piece 4 arranged opposite the free end 3, which is designed for tool-free fastening in an opening 12 of a gas nozzle 11 of a welding torch 10 (see Figure 1 The connecting piece 4 of the body 2 is formed by a truncated cone 5 which makes it easier to fasten the teaching tool 1 in the opening 12 of the gas nozzle 11 (see Figure 8 ). Connector 4 (see Figure 3 )'s average diameter D A Slightly larger than the diameter D of the opening 12 of the gas nozzle 11 of the welding torch 10 G , so that the teaching tool 1 is held in the gas nozzle 11 only by friction (see Figure 8 ).

[0039] Figure 3 A second embodiment of the teaching tool 1 is shown, wherein the teaching tool 1 has a diameter D F Greater than the maximum diameter D of the connecting piece 4 M The flange 6 is arranged between the connecting piece 4 and the free end 3 of the body 2. By means of the flange 6 as a kind of limitation of the teaching tool 1, it can be ensured that the teaching tool 1 is attached to the gas nozzle 11 in a desired position. The flange 6 prevents the teaching tool 1 from tilting relative to the gas nozzle 11 and always ensures that the tip of the teaching tool 1 is at a defined distance from the end of the gas nozzle 11.

[0040] Figure 4 A further embodiment of a teaching tool 1 is shown with a cylindrical connecting piece 4 having a diameter D greater than the opening 12 of the gas nozzle 11. G Slightly larger, preferably 4% to 8% of the outer diameter D A This cylindrical connection piece 4 does not fall within the scope of protection of the present invention. The tip on the free end 3 of the body 2 exhibits a rounded end 8, in particular with a diameter of 0.4 to 0.6 mm.

[0041] Figure 5 Another embodiment of the teaching tool 1 is shown, which is similar to the teaching tool according to Figure 3 All other aspects of the embodiment of the invention correspond. The connecting element 4 is formed by a truncated cone 5, the average diameter of which is D C Slightly larger than the diameter D of the opening 12 of the gas nozzle 11 GIn this embodiment, the body 2 of the teaching tool 1 is at least partially surrounded by a fluorescent surface layer 7. The fluorescent surface layer 7 can be applied by brushing, spraying, dipping or other coating methods. Instead of the fluorescent surface layer 7, fluorescent particles can also be mixed into the elastic material of the body 2 of the teaching tool 1. The fluorescent surface layer 7 can improve the visibility of the teaching tool 1 during the teaching process.

[0042] Figure 6 Shown according to Figure 3 The only difference is the recess 18 on the connecting piece 4 opposite the free end 3 of the body 2 of the teaching tool 1, in which the tip of the non-melting electrode 13 of the welding torch 10 can be placed during the teaching process (see Fig.10 ). The recess 18 is adapted to the shape of the top end of the non-melting electrode 13 accordingly.

[0043] Figure 7 A cross-sectional view of another embodiment of the teaching tool 1 is shown. The angle of the recess 18 is smaller than that of the Figure 6 If the elastic material of the body 2 of the teaching tool 1 contains graphite carbon C, on the one hand, the wear resistance and thus the service life of the teaching tool can be increased. On the other hand, this method or the addition of other conductive particles (e.g. nickel-plated copper powder or silver powder) can make the teaching tool 1 conductive. This means that the contact between the welding torch 10 or the teaching tool 1 and the workpiece W can be detected by short-circuit detection. For this purpose, the voltage U is measured. M It is applied to the teach tool 1 via a gas nozzle 11 and is detected by a voltage drop when the free end 3 of the teach tool 1 comes into contact with the electrically conductive workpiece W. In the event of contact, an acoustic signal and / or a visual signal may be emitted.

[0044] Figure 8 It shows that according to Figure 3 A partial cross-sectional view of a gas nozzle 11 according to the invention with a teaching tool 1 is shown in a second embodiment. The gas nozzle 11 has an opening 12 with a diameter D G The non-melting electrode 13 can remain in the gas nozzle 11 during the teaching process and only move backwards. This helps handling during the teaching process. The maximum diameter D of the connecting piece 4 M Slightly larger than the diameter D of the opening 12 of the gas nozzle 11 G The teaching tool 1 is inserted into the opening 12 of the gas nozzle 11. Due to the elastic material of the body 2 of the teaching tool 1, the teaching tool 1 can be simply inserted into the opening 12, where it is held due to friction. The flange 6 prevents the teaching tool 1 from tilting relative to the gas nozzle 11 and ensures that the distance between the end of the gas nozzle 11 and the tip at the free end 3 of the teaching tool 1 is correct.

[0045] Fig. 9 It shows that according to Figure 3 A partial cross-sectional view of another gas nozzle 11 of a teaching tool 1 according to the invention of a second embodiment is shown. Arrow G shows the path of the inert gas G in the gas nozzle 11 during the welding process.

[0046] final, Fig.10 It shows that according to Figure 7 A partial sectional view of a further gas nozzle 11 of a teaching tool 1 according to the invention in the illustrated embodiment. During the teaching process, the tip of the non-melting electrode 13 can be arranged in a recess 18 on the connecting piece 4 of the teaching tool 1 .

[0047] With the aid of the described teaching tool 1 , the teaching process can be improved and the risk of damaging the workpiece W or components of the welding torch 10 can be minimized or prevented.

Claims

1. A teaching tool (1) for a welding torch (10), in particular a plasma welding torch (15), the welding torch (10) having a gas nozzle (11) with an opening (12) for a non-melting electrode (13) having a tip (14), the teaching tool (1) being used in the case of teaching a welding path (X) along a workpiece (W) of the welding torch (10) attached to a welding robot (16), the teaching tool (1) comprising a substantially circular symmetrical body (2) with a free end (3), wherein the body (2) is formed of an elastic material, characterized in that The body (2) comprises a connection piece (4) arranged opposite the free end (3), the connection piece (4) being formed by a truncated cone (5) for tool-free fastening in the opening (12) of the gas nozzle (11) of the welding torch (10).

2. The teaching tool (1) according to claim 1, characterized in that The average diameter (D C ) is slightly larger than the diameter (D) of the opening (12) of the gas nozzle (11) of the welding torch (10) G ).

3. The teaching tool (1) according to claim 2, characterized in that The average diameter (D C ) is smaller than the diameter (D) of the opening (12) of the gas nozzle (11) of the welding torch (10) G ) is 4% to 8% larger.

4. The teaching tool (1) according to any one of claims 1 to 3, characterized in that Having a larger diameter (D) than the connecting piece (4) F ) is arranged between the connecting piece (4) and the free end (3) of the body (2).

5. The teaching tool (1) according to any one of claims 1 to 4, characterized in that The body (2) is made in one piece.

6. The teaching tool (1) according to any one of claims 1 to 5, characterized in that The elastic material of the body (2) contains, in particular, 30 to 40 volume percent graphitic carbon (C).

7. The teaching tool (1) according to any one of claims 1 to 6, characterized in that The body (2) is made of rubber or a rubber compound, in particular silicone rubber.

8. The teaching tool (1) according to any one of claims 1 to 7, characterized in that Fluorescent particles are mixed into the elastic material, or the body (2) is at least partially surrounded by a fluorescent surface layer (7).

9. The teaching tool (1) according to any one of claims 1 to 8, characterized in that The free end (3) of the body (2) has a rounded end (8) with a diameter of, in particular, 0.4 to 0.6 mm.

10. A welding torch (10), in particular a plasma welding torch (15), for a non-melting electrode (13), comprising a gas nozzle (11) with an opening (12) for the non-melting electrode (13) and a device (17) for mounting on a welding robot (16), characterized in that A teaching tool (1) according to any one of claims 1 to 9 is provided and fastened in the opening (12) of the gas nozzle (11).

11. A method for teaching a welding path (X) of a welding torch (10) attached to a welding robot (16) using a teaching tool (1), characterized in that The welding torch (10) passes through a desired welding path (X), and a teaching tool (1) according to any one of claims 1 to 9 is fastened to the welding torch (10).

12. The method according to claim 11, characterized in that The contact of the teaching tool (1) with the workpiece (W) is detected and the teaching of the welding path (X) is corrected accordingly.

13. The method according to claim 11, characterized in that The contact of the teaching tool (1) with the workpiece (W) is detected by a force (F) detected at the welding robot (16).

14. The method according to claim 12 or 13, characterized in that The contact between the teaching tool (1) and the workpiece (W) is established by measuring an electrical voltage (U M ) is detected.

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