WO1997045227A1

WO1997045227A1 - Wire-guiding elements for a plurality of approximately mutually parallel welding wires for a welding torch

Info

Publication number: WO1997045227A1
Application number: PCT/AT1997/000106
Authority: WO
Inventors: Josef Artelsmair; Martin Kepplinger
Original assignee: Fronius Schweissmaschinen Kg Austria
Priority date: 1996-05-29
Filing date: 1997-05-22
Publication date: 1997-12-04
Also published as: DE29780371U1; AU2880097A

Abstract

The invention concerns wire-guiding elements (8, 9) for a plurality of approximately mutually parallel welding wires (12, 13) for a welding torch (4). The welding wires (12, 13) can be moved relative to the wire-guiding elements (8, 9) by means of separately controllable wire-feed devices (10, 11). The wire-guiding elements (8, 9) are connected in an electrically conductive manner to a plurality of welding current sources (2, 3), the wire-guiding elements (8, 9) of the welding wires (12, 13) being electrically separate from one another. Each of the wire-guiding elements (8, 9) is connected to its own welding current source (2, 3).

Description

Wire guiding elements for several welding wires for a welding torch which run approximately parallel to one another

The invention relates to a wire guide element as described in the preamble of claim 1.

Several wire guide elements are already known, in which several welding wires are fed to the welding point via a common welding torch. The welding wires are supplied with energy, in particular with current and voltage, via a plurality of welding current sources, the current transfer from the welding current source to the welding wires taking place via a common conductive wire guide element. The disadvantage here is that if a short circuit occurs between one of the welding wires and the workpiece, the arc built up to form the second welding wire also extinguishes, since the entire current of the two welding current sources flows to the workpiece via the short circuit for the purpose of separating the arc which has been extinguished first, so that there are impairments in the welding quality and the welding bead.

The present invention has for its object to provide a wire guide element, a multiple wire welding device and an associated welding process, in which an independent control of the individual welding wires is guaranteed.

This object of the invention is achieved by the features in the characterizing part of claim 1. The advantage here is that the separate, electrically insulated arrangement of a plurality of wire guide elements enables independent control of the energy flow to the individual welding wires in the wire guide elements, so that when a short circuit or a fault occurs on a welding wire, the welding process in the area of the further welding wire can be continued without interference. Another unpredictable advantage is that if a short circuit arises between a welding wire and the workpiece, the latter is disconnected via the associated welding current source, the further welding wire or the welding process on the further welding wire being able to be continued independently of this. Another advantage is that the separately controlled material transfer from the welding wires can be achieved by the separate control of the wire guide elements. An embodiment according to claims 2 to 8 is also advantageous, since this prevents the energy emitted by the welding current sources, in particular the current pulses, from spreading between the wire guide elements.

An embodiment according to claims 9 and 10 is advantageous because it enables separate control of the cooling circuits for the wire guide elements, so that optimal cooling of the welding torch is ensured.

However, an embodiment according to claims 11 and 12 is also advantageous, since it enables simple coordination or a simple comparison of the individual welding current sources with one another and, at the same time, data exchange between the welding current sources can be carried out.

An embodiment according to claim 13 is also advantageous, since as a result the wire feed speed can be matched exactly to the individual welding processes for the possibly different welding wires.

The embodiment according to claim 14 advantageously ensures that the holding devices belonging to the prior art can be used for the welding torch.

However, an embodiment according to claim 15 is also advantageous, since this results in better positive contacting of the welding wires in the transition piece or in the contact socket.

In an embodiment variant according to claim 16, it is advantageous that an overlap of the arc or sparking between the two contact sockets or between the welding wires is prevented by an exact distance between the individual contact sockets or between the welding wires.

An embodiment according to claim 17 is also advantageous, since as a result the distance or the distance between the two contact sockets can be adapted to a wide variety of contact sockets.

However, an embodiment according to claims 18 to 20 is also advantageous since this prevents sparking or arcing between the contact sockets. Another advantage is that the arrangement of the Isolation cap cooling of the two contact sockets is achieved at the same time.

With the design according to claim 21 it is achieved that the welding wires are sealed off from the atmosphere, so that an adverse influence on the melting bath is prevented or a stable arc build-up is achieved.

The invention also encompasses a method for simultaneous welding with welding wires which are guided independently of one another in a plurality of separate wire guide elements, as described in the preamble of claim 22.

This method is characterized by the measures in the characterizing part of claim 22. It is advantageous here that if a fault occurs on an arc, this has no adverse effect on the further arc, so that at least the welding process for a welding wire can be continued undisturbed.

The measure according to claim 23 advantageously ensures that an improved material transfer between the welding wires and the workpiece can be achieved by controlling the welding wires via current pulses.

With the process sequence according to claim 24 it is achieved that the material transfer between the welding wires and the workpiece can be controlled synchronously or asynchronously.

The measures according to claim 25 are also advantageous since the wire feed speeds on the individual welding wires can thereby be adapted to different welding processes or different materials of the welding wires.

The measures according to claim 26 are also advantageous, since the welding processes for the two welding wires can thereby be matched to one another.

Finally, a method sequence according to claim 27 is also advantageous, since it enables the welding wires to be driven synchronously or asynchronously with energy from the welding current sources.

For a better understanding of the invention, it is described in more detail below using an exemplary embodiment. Show it:

Figure 1 is a diagram of a multiple wire welding device in a simplified, schematic representation.

2 shows a process sequence for controlling the multiple wire welding device;

3 shows a further process sequence for controlling the multiple wire welding device;

4 is a side view of a welding torch, cut and simplified schematic representation;

Fig. 5 is an end view of the welding torch, cut along the lines V-V in Fig. 4 and a simplified, schematic representation.

1 to 3, a welding method for a multiple wire welding device 1 is shown.

The multiple wire welding device 1 is formed from two individual, independently operated welding current sources 2, 3 with a welding torch 4 and two independent welding wire systems 5, 6. The welding current sources 2, 3 correspond to a current source, in particular an inverter current source, so that these welding current sources 2, 3 can be used independently of one another for other welding methods.

The two welding wire systems 5, 6 working independently of one another are assigned to a common welding torch 4 for a welding point 7. Each welding wire system 5, 6 comprises its own wire guide element 8, 9, which are arranged in the welding torch 4 in an electrically separate manner. The wire guide elements 8, 9 serve for the current transfer from the welding current sources 2, 3 to welding wires 12, 13 unwound from wire feed devices 10, 11 and their feeding to the welding point 7. In order to prevent the two wire guide elements 8, 9 from influencing one another an insulation layer 14 is arranged between the two wire guide elements 8, 9. The wire guide elements 8, 9 are each connected via a separate supply line 15, 16 to the positive potential of one of the two welding current sources 2, 3, whereas a workpiece 17 to be welded is connected via supply lines. gene 18, 19 is connected to the negative potential of the welding current sources 2, 3. Of course, it is possible that the two wire guide elements 8, 9 can be held at a distance from one another by means of a fastening element, as shown in dash-dotted lines, so that the insulation layer 14 is no longer absolutely necessary, since a corresponding air gap is formed between the two wire guide elements 8, 9 becomes.

In order to be able to carry out a welding process with the multiple wire welding device 1, the electrical energy is supplied from the two welding current sources 2, 3, for example by means of current pulses which can be changed with regard to their amplitude and / or frequency and / or width. Furthermore, it is advantageous but not mandatory for the welding process to form a protective gas envelope 20 around the welding point 7 in order to be able to carry out a perfect welding process. For this purpose, the welding torch 4 is connected to a gas bottle 22 via a gas supply line 21, so that a gas 23, in particular a protective gas, can be supplied to the welding point 7 via this gas supply line 21. However, it is also possible that the gas supply line 21 is not connected to the gas bottle 22, but to an in-house gas supply device.

In order to achieve a certain dependency of the two welding current sources 2, 3 on one another, the welding current sources 2, 3 are equipped with at least one synchronization unit 24, 25, the two synchronization units 24, 25 being connected to one another via a synchronization line 26. The synchronization units 24, 25 of the welding current sources 2, 3 have the task that the two welding current sources 2, 3 run synchronously internally, so that a mutual comparison between the two welding current sources 2, 3 can be carried out during the welding process. For this purpose, a clock generator is arranged in one of the two welding current sources 2, 3, which supplies the further welding current sources 2, 3 with a clock signal, so that the two welding current sources 2, 3 are controlled via a common clock generator for the control sequence of a welding process.

Furthermore, it is possible that the two synchronization units 24, 25 can be used for data transmission. This makes it possible for the data for the welding process to be set only at one welding current source 2, 3, for example at a master current source, which corresponds to the welding current source 2 and these are then transmitted to the synchronization unit 25 via the synchronization unit 24. The slave current source, in particular the welding power source 3, automatically set to the same welding parameters. Of course, it is possible that the data exchange between the two welding current sources 2, 3 does not take place via the synchronization unit 24, 25, but that each welding current source 2, 3 has its own interface, in particular a standard, parallel or serial interface via which the data transfer can be carried out. It is also possible that one of the two welding current sources 2, 3 or both welding current sources 2, 3 are equipped with several standard interfaces, so that an evaluation of the course of the welding process can be carried out using a computer, in particular a personal computer .

In order to be able to carry out a welding process with the multiple wire welding device 1, the individual welding parameters, such as, for example, wire diameter, welding current, welding method, etc., are switched from one user to one of the two welding current sources 2, 3, in particular at the welding current source 2, before the welding process begins. , which is then transferred via the synchronization units 24, 25 to the further or further welding current source (s) 2, 3 if more than two welding wires 12, 13 are used.

In order to be able to carry out the welding process according to the preset data, it is possible to carry out a start routine first. First, only one arc 27 is ignited between the workpiece 17 and the welding wire 12, the arc 27 being supplied via the welding current source 2. The arc 27 can be ignited, as is known from the prior art, by a simple high-frequency ignition. The state of a single arc 27 is maintained until the arc 27 is stabilized on the welding wire 12, i. This means that the heating of the welding wire 12 means that the arc 27 is no longer extinguished independently. After the arc 27 has stabilized, a further arc 28 is ignited for the second welding wire 13. This further arc 28 is now set up with current and voltage from the welding current source 3.

Then the speed of the wire feeders 10, 1 1 is increased so that the user can start the welding process. The speed of the wire feed devices 10, 11 can be increased independently of the welding current sources 2, 3 by control via control lines 29, 30. This start routine is necessary because by using several welding wires 12, 13 for a significantly higher welding speed, that is to say a significantly higher wire feed speed, is achieved in a single welding process. If the welding process started immediately with the corresponding wire feed speed in the unstabilized position of the arcs 27, 28, the arc 27 or 28 would extinguish or could not build up at all, which would affect the welding quality for the welding process.

In FIG. 2, the multiple wire welding device 1 shown in FIG. 1 is shown during a welding process. In addition, a separate current-time diagram is shown for each welding current source 2, 3, the current I being plotted on the ordinate in the current-time diagram and time t on the abscissa.

By using the pulse welding method for the multiple wire welding device 1, a uniform material removal for the two welding wires 12, 13 and a good material delivery or a material transfer to the welding point 7 is achieved. Another advantage of using the pulse welding process is that simple, separate control of the two welding wires 12, 13 is possible. The separate activation of the two welding wires 12, 13 is achieved in that the two wire guide elements 8, 9, which are responsible for the current transfer from the welding current source 2, 3 to the welding wire 12, 13, are insulated from one another by the insulation layer 14, so that a separate pulse welding process can be carried out for each individual welding wire 12, 13 without influences on the further welding wire 12 or 13.

In the pulse welding method used, the welding current sources 2, 3 after the start routine is completed, e.g. with synchronous operation, a current pulse 32, 33 is applied to the welding wires 12, 13 via the wire guide elements 8, 9 at a common time 31. The simultaneous application of the current pulses 32, 33 from the welding current sources 2, 3 is possible because the two welding current sources 2, 3 are internally synchronized with one another via the synchronization units 24, 25 and thus the transmission of the current pulses 32, 33 or the processing of individual work steps or program steps can be coordinated with one another by a central clock generator or time-coordinated clock generators.

By applying the current pulses 32, 33 to the welding wires 12, 13, it is achieved that within a defined for the transmitted current pulse 32, 33, Presettable time period 34 from the welding wires 12, 13, a material transition to the welding point 7 is achieved. The material transition occurs when the welding wires 12, 13 are heated by the material of the welding wires 12, 13 dripping into the weld pool 35 located at the welding point 7, so that a welding bead 36 can be formed.

After the time period 34 for the current pulses 32, 33 has elapsed, no energy is supplied to the welding wires 12, 13 over a further presettable time period 37, and then a current pulse 32, 33 is again applied to the welding wires 12, 13, which in turn causes a material transfer is achieved. The periodic transmission of the current pulses 32, 33 is carried out until the welding process is ended by the user. It is possible that the current level or the duration 34 of the current pulse 32, 33 and the period 37 in which no current pulse 32, 33 is emitted can be freely selected by the user during the welding process.

Due to the separate actuation of the two welding wires 12, 13, it is now possible for the arc 28 on the further welding wire 13 to be maintained in the event of a short circuit in a welding wire 12 or 13, for example the welding wire 12. This is possible in that the two wire guide elements 8, 9 are insulated from one another via the insulation layer 14, so that when the arc 27 for the welding wire 12 goes out, the regulation of the melting of the short circuit at the welding point 7 by increasing the current pulse 32 only from the Welding current source 2 is carried out so that mutual interference is excluded. If, as is known from the prior art, the wire guide elements 8, 9 were conductively connected to one another, that is to say that no separating insulation layer 14 was arranged, a short circuit would result in one of the two welding wires 12, 13 the further arcs 27 and 28 also go out and the entire energy of the second welding current source 2, 3 flows over the short-circuited welding wire 12 to separate the short circuit. The resulting excess current would result in relatively strong weld spatter from the weld pool when the short-circuit is opened, since the excessive current strength leads to an explosive disconnection of the short-circuit.

In the newly applied welding process, the electrical separation or the isolation of the two wire guide elements 8, 9 via the insulation layer 14 means that the energy supply to the individual welding wires 12, 13 or separate control via the welding current sources 2, 3 is achieved. With these welding methods, it is now possible for a welding wire to short-circuit

12 or 13, for example of the welding wire 12 with the workpiece 17, the arc 27 for the corresponding welding wire 12 is extinguished, although the arc 28 for the welding wire 13 is maintained. The disconnection of the short circuit between the welding wire 12 and the workpiece 17 is now carried out exclusively by the welding current source 2, so that an impairment of the arc 28 for the welding wire 13 is prevented. The separate activation now prevents an excess current from occurring at one of the two welding wires 12, 13, so that the short circuit can be separated almost without formation of spatter. A further advantage lies in the fact that the welding quality is increased by the separate activation of the two welding wires 12, 13, since if a short circuit occurs on one of the two welding wires 12 or 13, the further welding wire 12 or 13 causes a material transfer to the Welding point 7 is ensured so that an interruption of the welding bead 36 is prevented.

In the pulse welding process just described, the welding wires 12,

13 is controlled synchronously, i.e. a current pulse 32, 33 is transmitted synchronously from each welding current source 2, 3 at a common time 31.

In order to end the welding process, a corresponding stop routine is carried out synchronously by the welding current sources 2, 3. The user can initiate the stop routine by pressing a button on one of the two welding current sources 2, 3 using a switch on the welding torch 4 or when using the multiple wire welding device 1 in a welding robot. The stop routine is carried out in the reverse order to the previously described start routine. That that when the stop routine is initiated, the current supply via the corresponding welding current source 3 is ended first on a welding wire 12, 13, for example on the welding wire 13. When the power supply is ended, the arc 28 extinguishes

Welding wire 13, however, the arc 27 remains on the welding wire 12, since it is supplied with current and voltage via the welding current source 2 with the corresponding current pulse 32. At the same time or before the power supply to the welding wire 13 is interrupted, the welding current sources 2, 3 reduce the wire feed speed or, in the case of the corresponding welding wire 13, the wire feed speed is completely reduced. By maintaining an arc 27 for the welding wire 12 can the latter fill in the end crater that arises at the welding point 7, ie that a continuous welding bead 36 with a corresponding height is reached. After the end crater has been filled at the welding point 7, the user can switch off the further welding current source 2 by hand. Of course, it is possible for the end crater to be filled out automatically when used in a welding robot, so that the welding current source 2 can be switched off independently.

FIG. 3 shows a further possible control for a welding process using the pulse welding method of the multiple wire welding device 1, the control of the welding wires 12, 13 taking place asynchronously, ie in a phase delay. This is possible because the two wire guide elements 8, 9 are galvanically separated by the insulation layer 14.

When the welding wires 12, 13 are driven asynchronously, one of the two welding current sources 2, 3, for example the welding current source 2, sends out a current pulse 39 at a point in time 38, the current pulse 39 being applied to the welding wire 12 over a period of time 40. Within this time period 40 it is again ensured that a material transfer in the form of a welding drop from the welding wire 12 to the workpiece 17 or to the welding point 7 is achieved.

Due to the internal synchronization of the two welding current sources 2, 3, it is now possible for a current pulse 42 to be applied to the welding wire 13 from the further welding current source 3 at a preset point 41 offset from the first current pulse 39. The current pulse 42 in turn has a time period 43, so that it is again ensured that a material transition takes place from the welding wire 13 to the workpiece 17 or to the welding point 7 within this time period 43. However, it is possible that the time period 40, 43 for the two current pulses 39, 42 is selected differently. Furthermore, it is also possible that the times 38, 41 at which the current pulses 39, 42 are emitted are offset from one another in an adjustable manner. For example, a synchronous operation, as described in FIG. 2 and in which the current pulses 39, 42 are released simultaneously, can be converted to an asynchronous operation in which the transmission of the current pulses 39, 42 is offset to one another at different, preset or by the welding parameters automatically adjustable times 38, 41 is possible.

After a preset period of time 44 has elapsed, the welding current source 2 in turn sends the current pulse 39 to the welding wire 12, so that a further material transition is reached. This periodic repetition of the offset transmission of the current pulses 39, 42 ensures that a continuous weld bead 36 is produced on the workpiece 17. However, it is possible that the time period 44 can be defined differently between two current pulses 39 in order to obtain a melt pool 35 that is as homogeneous as possible.

The welding current source 3 in turn sends the current pulse 42 for the welding wire 13 after a preset time 45, so that a material transition to the welding point 7 is again achieved for the welding wire 13. Of course, it is also possible here that the individual successive current pulses 39, 42 are sent out with different time durations 44, 45, but the coordination of the transmission of the individual current pulses 39, 42 from the welding current sources 2, 3 via the synchronization units 24, 25 can take place, so that the chronological sequence of the material transitions of the welding wires 12, 13 can be freely selected. Of course, it is possible that the energy transfer to the welding wires 12, 13 and possibly the gas supply and the wire feed speed can be initiated and / or ended simultaneously or with an adjustable delay.

When using this asynchronous welding process, it is advantageous that the welding bead 36 is built up continuously on the workpiece 17, i.e. that the thickness of the welding bead 36 is built up in a single welding process by two material transitions of the welding wires 12, 13. It is also possible for the welding wires 12, 13 to be equipped with different alloys, so that, if desired, a multi-layer structure of the welding beads 36 can be achieved by a welding process.

Of course, it is possible that not only two welding wires 12, 13 are used in the multi-wire welding device 1 used, but that several welding wires 12, 13, for example three to four welding wires 12, 13, are used. It is then advantageous if, for each individual welding wire 12, 13 or a group of two or more welding wires 12, 13, a separate welding current source 2, 3 is arranged, or that the wire guide elements 8, 9 causing the current transfer are in turn provided by the others Wire guide elements 8, 9 are insulated, so that separate control of the individual welding wires 12, 13 is achieved. However, it is also possible that, for example, not two independent welding current sources 2, 3 for the multiple wire welding device 1 are used, but that in a single housing of a welding device or a welding current source 2 or 3, for example two individual, independently controllable welding current sources 2, 3, which can be operated independently of one another, are arranged, so that in turn a separate control of the individual Welding wires 12, 13 is reached.

The arrangement of the welding wires 12, 13 in the welding torch 4 can take place parallel or in succession to the welding point 7, the arrangement of the welding wires 12, 13 being able to be selected differently depending on the area of use.

When the welding wires 12, 13 are arranged parallel to one another and next to one another in the welding direction, the width of the weld bead 36 is substantially increased, as is necessary when welding two workpieces 17 together.

When the welding wires 12, 13 are arranged parallel to one another but one behind the other in the welding direction, the highest possible weld bead 36 is achieved in a welding process, as is advantageous in cladding.

FIGS. 4 and 5 show the welding torch 4 for the multiple wire welding device 1, the same reference numerals being used for the same parts of the previously described FIGS. 1 to 3. In the exemplary embodiment shown, the welding torch 4 is designed for use on a welding robot. Of course, it is also possible to build this welding torch 4 for a manual welding torch. For this purpose, the welding torch 4 can be made neutral, ie at an angle of 0 °, or the welding torch 4 can have a curvature of, for example, up to 60 °.

The welding torch 4 is formed from a tubular outer casing 46, onto which a gas nozzle 47 is attached in the end region. It is possible that the outer casing 46 can be formed from several individual parts. The outer casing 46 of the welding torch 4 is preferably made of a non-conductive material, so that no current can flow on the outer surfaces of the outer casing 46 during a welding process. This has the advantage that when the welding torch 4 is touched by a user, none during a welding process

There is a risk of electric shock. Of course, it is possible that the outer casing 46 can be formed by a steel tube or other materials An insulation layer is applied inside the outer casing 46, so that again no current can flow on the outer surfaces of the outer casing 46.

The power supply to the welding torch 4 takes place via a connecting piece 48 coupled to the welding torch 4. The connecting piece 48 consists, for example, of a plug connection 49 on which a hose package 50, 51, 52 is arranged. The hose packages 50, 51, 52 serve to convey the individual components, which are necessary for a welding process, to the welding torch 4. For this purpose, the gas supply line 21 and the supply lines 15, 16 are connected to the connection piece 48, so that the welding torch 4 with protective gas,

Energy, coolant, welding wire can be supplied. For this purpose, for example, the hose package 50 for the welding current source 2, the hose package 52 for the welding current source 3 and the hose package 51 for the gas bottle 22 are arranged.

It should be mentioned in principle with regard to the welding torch 4 that the insulation layer 14 is arranged in the middle of the outer casing 46. It is possible for the insulation layer 14 to extend to the edge region of the outer casing 46, so that the arrangement of this insulation layer 14 creates two semi-tubular components. However, it is also possible for the insulation layer 14 to be arranged only in the interior of the outer casing 46, so that the individual parts, in particular the

Wire guide elements 8, 9, which are located inside the outer casing 46, are designed as semi-tubular parts. For the sake of simplicity, however, it is referred to as tubular structures, since in principle 4 tubular objects are used for the construction of the welding torch, which are then divided and then connected again after the insulation layer 14 has been interposed.

Furthermore, a fastening tube 53 for a holder on a welding robot is arranged on the outer casing 46, in particular for the wire guide elements 8, 9.

The wire guide elements 8, 9, which are composed of a supply piece 54 and a transition piece 55, are arranged in the interior of the outer casing 46. The supply piece 54 consists of a full-surface copper tube 56, this copper tube 56 being divided into two parts 57, 58 by the arrangement of the insulation layer 14 in the middle of the outer casing 46. Of course, it is possible that the copper tube 56 made of a solid material with a plastic cross cut can be formed. Due to the arrangement of the insulation layer 14 in the middle of the copper tube 56, a separate current supply through the supply piece 54 is achieved. The supply piece 54 or the two parts 57, 58 of the copper tube 56 are each connected via the plug connection 49 to the supply lines 15 or 16 of the welding current sources 2 or 3, so that the supply piece 54 is used for separate power supply for both welding wires 12 and 13, respectively can be.

The welding torch 4 also has two cooling circuits 59, 60 which can be regulated independently of one another. In each case one cooling circuit 59, 60 is assigned to a welding current source 2, 3, the supply of the cooling circuit 59, 60 being supplied, for example, by a cooling liquid supplied via a hose via the plug connection 49. The two cooling circuits 59, 60 are each assigned to a wire guide element 8, 9 and are controlled independently of one another via a control device arranged in the welding current source 2, 3. The cooling circuits 59, 60 are connected to a cooling system arranged in the welding current sources 2, 3. Of course, it is possible that one or more external cooling systems can be used instead of the cooling systems arranged in the welding current sources 2, 3, whereby when using external cooling systems these are controlled by additional lines from the welding current sources 2, 3.

The first cooling circuit 59 is formed from at least two bores 61 for the water flow and the water return and extends from the plug connection 49 via the supply piece 54 into the transition piece 55 of the wire guide element 8. From the transition piece 55, the two bores 61 are connected via hose lines 62, 63 out of the interior of the welding torch 4. The hose lines 62, 63 are connected to connecting pieces 64, 65 arranged on the gas nozzle 47. The connecting pieces 64, 65 are connected to a cooling ring 66 running around the gas nozzle 47 and protrude into the interior of the cooling ring 66. The cooling ring 66 has a groove 67 facing the gas nozzle 47, but between the two connecting pieces ken 64, 65 in the groove 67 of the cooling ring 66 a partition 68 is arranged so that the pumped in the holes 61 coolant, in particular a cooling liquid, must flow around the outer circumference of the gas nozzle 47 before it flows back into the further bore 61 to the connector 49 can. In the first cooling circuit 59, a bore 61 is used for the coolant supply and the further bore 61 for the coolant return, so that a closed circuit can be established between one of the two welding current sources 2, 3 and the welding torch 4. The second cooling circuit 60 in turn extends from the plug connection 49 via the supply piece 54 of the further wire guide element 9 into the transition piece 55 and is again formed by bores 61. In the transition piece 55, the bores 61 extend as far as the end region 69 of the transition piece 55. At the end region 69 of the transition piece 55 there is in turn a circumferential groove 70 through which the two bores 61 are connected via further bores 71. The groove 70 is designed so that it extends over the entire end region 69 of the two wire guide elements 8, 9. If a coolant is now pumped into one of the two bores 61, this coolant exits from the inside of the wire guide element 9 via the bore 71 into the groove 70. From there the coolant flows on the circumference of the transition piece 55 of the two wire guide elements 8, 9 to the further bore 71 and then enters the interior of the wire guide element 9, that is to say in the bore 61, through the bore 71, as a result of which the coolant return closed is.

It is advantageous in this arrangement of the two cooling circuits 59, 60 that the gas nozzle 47 and the transition piece 55 can be cooled at the same time. It is advantageous that the two cooling circuits 59, 60 can be controlled independently of one another, so that different control of the two cooling circuits 59, 60 is possible when different temperatures occur at the gas nozzle 47 or at the transition piece 55. Another advantage is that the separation of the two cooling circuits 59, 60 into the two wire guide elements 8, 9 achieves simultaneous cooling of the wire guide elements 8, 9.

A further bore 72 is arranged in the two parts 57, 58 of the copper tube 56. The bore 72 has the task of guiding the welding wire 12 or 13 from the plug connection 49 to the transition piece 55 adjoining the supply piece 54. The bore 72 has a substantially larger diameter 74 than a diameter 73 of the welding wire 12 or 13. The larger diameter 74 of the bore 72 makes it possible for the gas 23, in particular the protective gas, to additionally flow through the bore 72 to the transition piece 55. By conveying the gas 23 through the bore 72 with the welding wire 12 or 13 it is achieved that no air can get into the welding torch 4, so that the welding wire 12 or 13 cannot oxidize and thus a good current transfer to the welding wire 12 or 13 is reached.

Furthermore, it is possible for the welding wire 12 or 13 in the bores 72 an additional guide device is arranged so that a stable feed of the welding wire 12 or 13 to the transition piece 55 is achieved.

The connecting piece 55 is arranged next to the supply piece 54, and the connecting piece 54 can be connected to the transition piece 55 by soldering, welding, gluing or screwing. The transition piece 55 can be formed from several individual parts, which are then assembled into a single part. It is again provided that the insulation layer 14 is arranged in the middle of the transition piece 55, so that the transition piece 55 is again divided into two halves. The transition piece 55 is formed from a conductive material, in particular copper, so that the transition piece 55 in turn acts as a feeder line for the current to one or more contact sockets 75, 76 adjoining the transition piece 55, in which a bore 77, 78 for the welding wires 12, 13 is arranged, can be used. Of course, it is possible that only one contact socket 75 and 76 is arranged instead of the two contact sockets 75, 76, contact sockets 75 and 76 with bores 77, 78 for the separated one being separated in this by the insulation layer 14 Feeding of the welding wires 12, 13 can be arranged. The two wire guide elements 8, 9 are connected via their side surfaces 79 via the insulation layer 14 and thus separate the welding torch 4 into two mirror-image halves.

An opening 80, 81 for guiding the welding wires 12, 13 is arranged in alignment in the transition piece 55 for each bore 72. The openings 80, 81 have a special course, in particular an angular course, in the direction of a central longitudinal axis 82 of the welding torch 4, the openings 80, 81 being aligned parallel to the central longitudinal axis 82 at a corresponding distance from the central longitudinal axis 82. The special design of the openings 80, 81 ensures that the welding wire 12, 13 is deflected in the direction of the central longitudinal axis 82 and then runs parallel to the central longitudinal axis 82. This has the advantage that a forced contact is achieved due to the opposite deflection of the welding wires 12, 13 in the openings 80, 81 or in the bores 77, 78 of the contact sockets 75, 76, so that a perfect current transfer from the transition piece 55 or from the contact sockets 75, 76 to the welding wires 12, 13. Furthermore, the openings 80, 81 have a plurality of bores 83 running around their circumference, through which the gas 23 can flow out from the openings 80, 81 in the direction of the gas nozzle 47, so that the gas 23 is passed along the gas nozzle 47. By passing the gas 23 laterally past the transition piece 55 A protective gas envelope 20 is formed around the welding point 7. For this purpose, it is possible that a gas distributor ring 84 is arranged over the transition piece 55. The gas distributor ring 84 has bores 85 arranged next to one another around its circumference. These holes 85 have the task of distributing the gas 23, which exits through the openings 80, 81 into the interior of the gas nozzle 47, uniformly around the circumference of the gas nozzle 47, so that a uniform protective gas envelope 20 forms around the welding wires 12, 13 becomes. The welding wires 12, 13 are guided in the outlet area from the wire guide elements 8, 9 through an outlet opening of the gas nozzle 47, so that the protective gas envelope 20 ensures that the two welding wires 12, 13 are sealed off from the atmosphere.

The contact sockets 75, 76 for each opening 80, 81 and one contact socket 75 and 76 for both openings 80, 81 are then arranged on the side of the transition piece 55 opposite the supply piece 54. It is possible that the openings 80, 81 are formed with a thread, so that the contact bushings 75, 76 can be screwed into the openings 80, 81. Of course, it is also possible that a snap or bayonet lock can be used for the contact sockets 75, 76 instead of a thread.

So that a welding process can now be carried out with the welding torch 4 according to the invention, care must be taken to ensure that a certain distance 86 is maintained between the two welding wires 12, 13 emerging from the contact sockets 75, 76 and between the contact sockets 75, 76, otherwise when an arc 27, 28 is ignited, the arc 27 or 28 could jump from a welding wire 12 to the further welding wire 13. If the distance 86 between the welding wires 12, 13 were to be chosen too small, then a mutual magnetic influence would arise between the welding wires 12, 13 due to the protective gas envelope 20, so that instead of several material transitions, a common material transition would occur, ie instead of a large common sweat drop is formed from two individual small sweat drops. However, if the distance 86 between the two welding wires 12, 13 were chosen too large, pore formation in the weld pool 35 may occur at the welding point 7, ie that a common weld pool 35 would not be formed for the two welding wires 12, 13 , but that the melt pool 35 would cool due to the excessive distance 86, so that a separate melt pool 35 is formed for the two welding wires 12, 13, which results in pore formation on the melt pool 35. For this purpose, it is possible that a between the contact sockets 75, 76 Insulation cap 87 is arranged. The insulation cap 87 forms a protective shield between the two contact sockets 75, 76 and is formed from an insulation material, for example from polished silicon nitrite (SiN A). The insulation cap 87 is designed such that it fits onto the transition piece 55 of the two wire guide elements 8, 9 connected via the insulation layer 14. Furthermore, the insulation cap 87 has a projection 88 which is adapted to the distance between the two contact sockets 75, 76, so that when the insulation cap 87 is plugged in, the space between the contact sockets 75, 76 is filled by the projection 88.

It is advantageous due to the arrangement of the insulation cap 87 that no welding spatter that occurs on the weld pool 35 or due to a short circuit can be deposited in the space between the two contact sockets 75, 76. This is because the deposits of welding spatter between the contact sockets 75, 76 would reduce the distance, as a result of which arcing and / or arcing would occur between the contact sockets 75, 76. Another advantage is that the insulation cap 87 is made of a material that is both heat-resistant and non-adhesive for welding spatter.

Furthermore, it is also possible for the ends of the contact sockets 75, 76 to be angled, as is shown in broken lines. The angular design of the contact sockets 75, 76 ensures that the two bores 77, 78 arranged in the contact sockets 75, 76 for the welding wire 12, 13 are almost prevented from closing by the welding spatter, but it should be noted that when the contact sockets 75, 76 are formed at an angle, the projection 88 of the insulation cap 87 ends with the ends of the contact sockets 75, 76.

Furthermore, care must be taken to ensure that, due to the different dressings of the welding wires 12, 13, when changing the welding wires 12, 13 or when inserting a new welding wire 12, 13, the distance 86 when emerging from the contact sockets 75, 76 must be redefined . To avoid this, it is necessary that a straightening path for the welding wires 12, 13 is arranged before the welding wires 12, 13 enter the welding torch 4. The straightening path can consist of a straightening path that is part of the prior art, such as two rollers. If a straightening path for the welding wires 12, 13 were not arranged, the distance between the welding wires 12, 13 could vary, so that the arc 27, 28 jumps from one welding wire 12 to the other Welding wire 13 or vice versa can not be excluded. This is possible because when the welding wire is stored on welding rollers, a corresponding dressing or bend is arranged in the welding wires 12, 13, so that when wire feeders 10, 11 are unwound, this bend is maintained in the welding wire, so that when exiting from the contact bushes 75, 76 the welding wire 12, 13 tries to deform back into the bend predetermined by the welding wire rolls. In order to avoid this, the welding wire 12, 13 must be stretched in a straight line before entering the welding torch 4 or in the welding torch 4, so that no deformation of the welding wire 12, 13 occurs when the welding wire 12, 13 emerges from the contact bushings 75, 76 more comes about.

It is of course possible that the distance 86 can be changed by means of appropriate devices, so that the distance 86 can be adapted for special welding processes or for different wire diameters or contact sockets 75, 76.

Furthermore, it is possible for the wire guide element 8, 9 to be designed as a common component. It is also possible for the contact socket 75, 76 to be formed as a common structural unit, the contact socket 75 and 76 being electrically separated from one another between the bores 77, 78. As a preferred embodiment, the wire guide element 8, 9 is designed as a cylinder section with a circular section or a cross-sectional cross-section, the insulation layer 14 being arranged between the cross-sectional cross-section.

Finally, for the sake of order, it should be pointed out that individual components and assemblies are shown disproportionately and to scale in the drawings for a better understanding of the invention.

Individual features of the individual exemplary embodiments can also form the subject of independent inventions with other individual characteristics of other exemplary embodiments, or in each case on their own.

Above all, the individual in FIGS. 1 to 3; 4 and 5; shown versions form the subject of independent, inventive solutions. The relevant tasks and solutions according to the invention can be found in the detailed descriptions of the figures. Set of reference symbols

1 multi-wire welding device 41 point in time

2 welding power source 42 current pulse

3 welding power source 43 time duration

4 welding torches 44 time duration

5 welding wire system 45 time duration

6 Welding wire system 46 outer sheathing

7 welding point 47 gas nozzle

8 wire guide element 48 connector

9 wire guide element 49 plug connection

10 wire feeder 50 hose package

11 Wire feed unit 51 hose package

12 welding wire 52 hose package

13 welding wire 53 mounting tube

14 insulation layer 54 supply piece

15 supply line 55 transition piece

16 supply line 56 copper pipe

17 workpiece 57 parts

18 supply line 58 parts

19 Supply line 59 Cooling circuit

20 protective gas sleeve 60 cooling circuit

21 gas supply line 61 bore

22 Gas bottle 62 hose line

23 Gas 63 hose line

24 synchronization unit 64 connector

25 synchronization unit 65 connector

26 synchronization line 66 cooling ring

27 arc 67 groove

28 arc 68 partition

29 Control line 69 End area

30 control line 70 slot

31 Time 71 hole

32 current pulse 72 hole

33 current pulse 73 diameter

34 duration 74 diameter

35 weld pool 75 contact socket

36 welding bead 76 contact socket

37 Duration 77 hole

38 Time 78 hole

39 current pulse 79 side surface

40 duration 80 breakthrough 81 breakthrough

82 central longitudinal axis

83 hole

84 Gas distribution ring

85 hole

86 distance

87 insulation cap

88 head start

Claims

Patent claims

1.Wire guide elements for a plurality of welding wires for a welding torch which run approximately parallel to one another and which can be moved relative to the wire guide elements via separately controllable wire feed devices which are electrically conductively connected to a plurality of welding current sources, characterized in that the wire guide elements (8, 9 ) the welding wires (12, 13) are electrically separated from each other and each of the wire guide elements (8, 9) is connected to its own welding current source (2, 3).

2. Wire guide elements according to claim 1, characterized in that the wire guide elements (8, 9) for a plurality of welding wires (12, 13) are formed as a common component.

3. Wire guide elements according to claim 1 or 2, characterized in that each wire guide element (8, 9) from several in the conveying direction of the welding wires (12, 13) arranged one behind the other, interconnected individual parts is formed.

4. Wire guide elements according to claim 3, characterized in that the individual parts of each wire guide element (8, 9) by a one end of a transition piece (55) connected to the supply piece (54) and the other end connected to the same contact socket (75, 76 ) are formed for the welding wire (12, 13).

5. Wire guiding elements according to claim 4, characterized in that the contact sockets (75, 76) for a plurality of welding wires (12, 13) are arranged electrically separated from one another in a common structural unit.

6. Wire guide elements according to one or more of claims 1 to 5, characterized in that the wire guide element (8, 9) is designed as a cylinder section with a circular section or circular segment-shaped cross section.

7. Wire guide elements according to one or more of claims 1 to 6, characterized in that an insulation layer (14) is arranged between the wire guide elements (8, 9).

8. Wire guide elements according to one of claims 6 or 7, characterized ge indicates that the wire guide elements (8, 9) in the region of their side surface (79) are connected via the insulation layer (14).

9. wire guide elements according to one or more of claims 1 to 8, characterized in that in each wire guide element (8, 9) a cooling circuit (59, 60) is arranged, the first cooling circuit (59) on the wire guide element (8 ) and the gas nozzle (47) and the second cooling circuit (60) on the wire guide element (9) and the transition piece (55).

10. Wire guide elements according to claim 9, characterized in that the cooling circuits (59, 60) are connected to at least one control device in the welding current sources (2, 3) for independent control.

1 1. Wire guide elements according to one or more of claims 1 to 10, characterized in that the wire guide element (8, 9) associated welding current source (2, 3) has at least one synchronization unit (24, 25) which with each welding current source (2, 3) is connected to the line.

12. Wire guide elements according to one or more of claims 1 to 1, characterized in that each welding current source (2, 3) is assigned a synchronization unit (24, 25) which are connected to one another via a synchronization line (26).

13. Wire guide elements according to one or more of claims 1 to 12, characterized in that the wire feeders (10, 1 1) associated with each welding wire (12, 13) of welding wire systems (5, 6) can be controlled independently of one another.

14. Wire guide elements according to one or more of claims 1 to 13, characterized in that the wire guide elements (8, 9) are arranged in an outer casing (46) of the welding torch (4).

15. Wire guide elements according to one or more of claims 1 to 14, characterized in that the welding wire (12, 13) over a portion of the wire guide element (8, 9) is arranged at an angle to a central longitudinal axis (82) of the welding torch (4) .

16. Wire guide elements according to one or more of claims 1 to 15, characterized in that the contact sockets (75, 76) or the welding wires (12, 13) are arranged at a distance from one another which prevents a spark and / or arc transition (86) .

17. Wire guide elements according to one or more of claims 1 to 16, characterized in that the distance (86) between the welding wires (12, 13) is adjustable.

18. Wire guide elements according to one or more of claims 1 to 17, characterized in that an insulation cap (87) is arranged in the end region (69) of the transition piece (55) of the wire guide elements (8, 9).

19. Wire guide elements according to claim 18, characterized in that the insulation cap (87) has a projection (88) which the distance between the

Fills contact sockets (75, 76).

20. Wire guide elements according to one of claims 18 or 19, characterized ge indicates that the insulation cap (87) is formed from a non-conductive material, for example silicon nitride.

21. Wire guide elements according to one or more of claims 1 to 20, characterized in that the welding wires (12, 13) in the outlet area from the wire guide elements (8, 9) through an outlet opening of a gas nozzle enveloping this outlet area (47) for a gas (23), in particular a protective gas, are passed through.

22. Method for simultaneous welding with welding wires which are guided independently of one another in a plurality of separate wire guide elements, in which one or more arcs are built up between the welding wires and the workpiece by supplying electrical energy via the welding wires, possibly within a gas jacket, and thereby the liquefied basic materials to be welded and mixed with the material of the welding wires, characterized ge indicates that the electrical energy is supplied to each of the welding wires independently of one another from its own welding current source.

23. The method according to claim 22, characterized in that the electrical Energy is supplied by means of variable current pulses.

24. The method according to any one of claims 22 or 23, characterized in that the control functions of the two welding current sources are synchronized.

25. The method according to one or more of claims 22 to 24, characterized in that the advancement of the welding wires takes place independently of one another.

26. The method according to one or more of claims 22 to 25, characterized in that the energy transfer to the welding wires and optionally the gas supply and the wire feed speed can be initiated and / or ended simultaneously or with an adjustable delay.

27. The method according to one or more of claims 19 to 26, characterized in that the time sequence of the material transitions of the welding wires can be freely selected.