Welding method and welding device for carrying out said welding method

The invention relates to a method and a device for arc welding according to the preambles of claims 1 and 20.

An electrode feed control is known from DE 25 50 278 A1, in which the electrode feed is stopped when the electrode is touched on the workpiece to ignite the arc between the electrode and the workpiece, especially during cold or hot starts, and then the electrode is stopped to ignite the arc is withdrawn. After the arc has been ignited, the electrode is again moved in the direction of the workpiece for the actual welding process. The disadvantage here is that no or only a limited or arbitrary change in the forward movement of the electrode is carried out during the welding process, i.e. after the first ignition of the arc, in particular after a cold start or a hot start, so that if a short circuit occurs, it will through an increase in current is to be resolved and thus weld spatter can arise.

Furthermore, from EP 0 142 915 A1 and US Pat. No. 4,485,293 A, a control for a wire feed is described in which the drive, in particular the motor, or the welding process is controlled as a function of the arc voltage or the motor speed, but during During the welding process, the electrode or welding wire is always conveyed in the direction of the workpiece.

A method for igniting and maintaining an arc for arc welding is known from EP 0 904 883 A1. The arc or the ignition process is supplied by a regulated energy source. The welding wire is moved in the direction of the workpiece until contact is made, i.e. until a short circuit is formed, as a result of which the welding wire is then supplied with energy from the energy source. The welding wire is then moved away from the workpiece, so that the arc is ignited by lifting the welding wire from the workpiece, that is, by breaking the short circuit. The backward movement of the welding wire from the workpiece is continued until a corresponding arc length is reached, whereupon the movement of the welding wire in the direction of the workpiece, that is, is reversed into a forward movement. At this point, the arc ignition process is complete, so that a continuous forward movement in the direction of the workpiece can be used to carry out a welding process, with a higher current pulse than the set welding current when a short circuit occurs, i.e. when the welding wire hits the surface of the workpiece is applied to the welding wire, so that a melting of the short circuit and thus a metal droplet detachment is achieved. However, the forward movement of the welding wire is maintained.

The disadvantage here is that the increase in the welding current in the form of a current pulse leads to a melting of the metal droplet and, due to the high current intensity, weld spatter occurs at the time the short circuit is broken.

The present invention is based on the object of creating a method and a device for igniting and maintaining an arc in which the welding quality of the welding process is significantly improved.

This object of the invention is achieved by the characterizing measures of claim 1. The advantage here is that the process sequence is controlled in such a way that if a short circuit occurs between the welding wire and the workpiece, after the ignition process has been completed, the feed movement, i.e. the forward movement, of the welding wire is regulated, with the forward movement being briefly stopped and / or vice versa and thus the short circuit is canceled. This ensures that the welding current can be kept constant, that is to say that an increase in current, as is usually necessary to break a short circuit, can be omitted. This also eliminates weld spatter, which inevitably occurs when the short circuit breaks due to an increase in current, which effectively prevents incorrect, unclean welding results. Another advantage is that relatively small weld seams can be achieved completely spatter-free even with thick wires and so-called micro-welds can be made on very thin metal sheets with thin wires. This is only possible because the detachment of the metal droplet is no longer generated with a very high current pulse, but the detachment is carried out by the backward movement of the welding wire and the surface tension of the weld pool.

AT 409 832 B

The advantage of the measures according to claims 2 to 11 is that a spatter-free welding process can be carried out without a large control or regulating wall.

Measures as described in claims 12 to 14 are also advantageous here, because they can be used as a basis for the regulation parameters specified as a function of the process and a rapid reaction required to control such processes is made possible. Due to the controlled influence on the feed movement of the welding wire, taking into account the specified process parameters, the heat input is kept significantly lower according to these measures compared to methods known from the prior art, whereby this method is particularly suitable for a welding process of very thin materials and the design of the devices for welding wire feed is simplified by the applicability of welding wires with a larger cross section.

According to the advantageous further measures as described in claims 15 and 16, the applicability of the method is achieved for all welding devices forming the state of the art and thus the broad spectrum of different applications is covered.

Finally, measures as described in claims 17 to 19 are also advantageous because they achieve the required short reaction time when the drive of the feed device is activated and, in particular, the rapid reversal of the direction of movement of the welding wire.

The object of the invention is also achieved by the characterizing features of claim 20. The surprising advantage here is that by reversing the drive of the feed device and thus the direction of movement of the welding wire, the periodically occurring short-circuit phases in the welding process, which always occur when a melting part, in particular the metal droplet, of the welding wire passes into the weld pool, are eliminated without the need for corrections in the position of the welding torch relative to the workpiece. However, current increase measures for breaking a short circuit, which mostly also cause weld spatter and have a negative effect on the welding result, are not necessary.

An embodiment as described in claim 21 is also advantageous here, since a very rapid movement reversal can be carried out with a drive by means of a servomotor.

A further advantageous embodiment also describes claim 22, because this means that inexpensive, commercially available devices can be used.

According to the advantageous development as described in claim 23, there are a large number of alternatives for driving such a feed device for the welding wire.

According to the further advantageous embodiment as described in claim 24, a high precision of the feed device is achieved and this design is particularly suitable for use in the micro-welding area, ie where very precise control processes are particularly important.

Finally, however, an embodiment as described in claims 25 and 26 is also possible, as a result of which a very cost-effective design using components that are less prone to failure is possible.

For a better understanding of the invention, it is explained in more detail with reference to the exemplary embodiments described in the following figures.

Show it:

1 shows a schematic representation of a welding device with the individual components in a simplified, schematic representation;

2 shows a simplified block diagram for carrying out the welding method according to the invention with a welding device according to the invention;

3 shows a diagram with the progression of the advance of the welding wire for carrying out the method according to the invention;

4 shows a diagram of the voltage profile when the method according to the invention is carried out;

5 shows a diagram of a current curve when the method according to the invention is carried out;

6 shows a diagram of a further variant of the current curve when the

AT 409 832 B method according to the invention:

7 shows a diagram of another possible current curve when the method according to the invention is carried out:

8 shows an embodiment of a feed device for the welding wire of the welding device according to the invention in a view;

9 shows another embodiment of the feed device for the welding wire for the welding device according to the invention in a view;

10 shows a further embodiment of the feed device for the welding wire for the welding device according to the invention in a view;

11 shows a schematic diagram for controlling the drive of the feed device for the welding wire of the welding device according to the invention.

By way of introduction, it should be noted that in the differently described embodiments, the same parts are provided with the same reference numerals or the same component designations, whereby the disclosures contained in the entire description can be transferred accordingly to the same parts with the same reference numerals or the same component designations. The position details chosen in the description, such as above, below, to the side, etc. based on the figure immediately described and shown and are to be transferred accordingly to the new position in the event of a change in position. Furthermore, individual features or combinations of features from the different exemplary embodiments shown and described can also represent independent, inventive or inventive solutions.

1 shows a welding system or a welding device 1 for a wide variety of welding processes, such as, for example, MIG / MAG welding or TIG welding, or electrode welding processes.

The welding device 1 comprises a power source 2 with a power section 3, a control device 4 and a switching element 5 assigned to the power section 3 or the control device 4. The switching element 5 or the control device 4 is connected to a control valve 6 which is in a supply line 7 for a gas 8, in particular a protective gas such as CO2, helium or argon and the like, is arranged between a gas reservoir 9 and a welding torch 10.

In addition, a feed device 11, which is common for MIG / MAG welding, can be controlled via the control device 4, a welding wire 13 being fed from a supply drum 14 into the area of ​​the welding torch 10 via a supply line 12. It is of course possible for the feed device 11, as is known from the prior art, to be integrated in the welding device 1 and not, as shown in FIG. 1, to be designed as an additional device.

The current for setting up an arc 15 between the welding wire 13 and a workpiece 16 is fed via a supply line 17 from the power unit 3 of the power source 2 to the welding torch 10 or the welding wire 13, whereby the workpiece 16 to be welded is also connected to the via a further supply line 18 Welding device 1, in particular with the power source 2, is connected and thus a circuit can be established over the arc 15.

To cool the welding torch 10, the welding torch 10 can be connected to a coolant container 21 via a cooling circuit 19 with the interposition of a flow monitor 20, whereby when the welding torch 10 is started up, the cooling circuit 19, in particular a liquid pump used for the liquid in the coolant container 21, is started can and thus a cooling of the welding torch 10 or the welding wire 13 is effected.

The welding device 1 also has an input and / or output device 22 by means of which the most varied of welding parameters or operating modes of the welding device 1 can be set. The welding parameters set via the input and / or output device 22 are forwarded to the control device 4 and the individual components of the welding system or the welding device 1 are then controlled by this.

Furthermore, in the exemplary embodiment shown, the welding torch 10 is connected to the welding device 1 or the welding system via a hose package 23. The individual lines from the welding device 1 to the welding torch 10 are arranged in the hose package 23.

AT 409 832 B

The hose package 23 is connected to the welding torch 10 via a prior art connection device 24, whereas the individual lines in the hose package 23 are connected to the individual contacts of the welding device 1 via connection sockets or plug connections. In order to ensure a corresponding strain relief of the hose package 23, the hose package 23 is connected to a housing 26 of the welding device 1 via a strain relief device 25.

In FIGS. 2 to 7, in particular in FIG. 2, the welding device 1 with the power source 2 is shown in a simplified, schematic representation. According to this illustration, the individual components of the power section 3 and the control device 4 are arranged in an integrated manner in the welding device 1. The power source 2 is connected to the welding torch 10 or the workpiece 16 via the supply lines 17, 18. So that the feed device 11 can be controlled, the control device 4 is connected to the feed device 11 via control lines 27, 28. The feed device 11 has the storage drum 14 with the welding wire 13 and a drive device 29, for example formed by conveyor rollers 30, 31, and a drive 32.

To form the arc 15 between the welding wire 13 and the workpiece 16, the process sequence described below is controlled and monitored by the control device 4. According to the embodiment shown, the power section 3 is line-connected to an external, preferably regulated, energy source 33.

It is possible to implement a welding process in which the control device generates an output signal to change the direction of advance of the welding wire as a function of the arc voltage, the advance movement after the arc voltage has dropped to or below a process-dependent predetermined minimum value stopped and / or the direction of the feed movement is reversed, so that after an increase and reaching or If the target value of the arc voltage is exceeded, the direction of the feed movement is reversed again.

In FIGS. 3 to 5, the interrelationship between wire feed, voltage and a possible regulated current profile is now shown on the basis of diagrams. 3 shows the feed speed Vd of the welding wire 13 as a function of the time t, which is plotted on the abscissa of the diagram. The curve of the feed rate Vd in the area above the abscissa represents a forward movement of the welding wire 13 in the direction of the workpiece 16 and the curve below the abscissa a backward movement, which leads to the welding wire end being removed from the workpiece 16. 4 shows the voltage profile and FIG. 5 shows the current profile on the welding wire 13 with the curve profile of the voltage U and the curve profile of the current I.

In the welding process shown, an ignition process known from the prior art is used to ignite the arc 15 for the first time, such as from EP 0 904 883 A, for example, so that this ignition process will no longer be discussed in greater detail. It is of course possible that any further ignition methods known from the prior art, in particular for short-circuit welding, can be used. It is not necessary that a forward and backward movement of the welding wire 13 must be carried out for the first ignition of the arc 15, but that the ignition can be carried out by simply feeding it, that is, by a forward movement of the welding wire 13, that is, for example, a High frequency ignition can also be used.

At a point in time 34, the welding process, in particular the ignition process, is started. A forward movement of the welding wire 13 is initiated by the control device 4. At the same time, the power source 2 is activated, so that a corresponding energy supply for the welding wire 13 is established. At a point in time 35 a short circuit occurs between the workpiece 16 and the welding wire 13, ie the welding wire 13 has accumulated on the surface of the workpiece 16, so that the voltage applied to the welding wire 13 collapses and the current begins to flow. This short circuit between the welding wire 13 and the workpiece 16 is recognized by the control device 4, whereupon it initiates a reversing movement of the welding wire 13, that is, a backward movement.

At a point in time 36, the welding wire 13 lifts from the surface of the workpiece 16 and the arc 15 is automatically ignited. This is recognized by the control device 4. The backward movement of the welding wire 13 can be continued, for example, as long as

AT 409 832 B until a corresponding, presettable arc length is formed. After the preset arc length has been reached, the backward movement of the welding wire 13 is again reversed into a forward movement, as can be seen at a point in time 37. At the same time, the current is increased so that a stable arc 15 can be built up. At a point in time 38, the arc 15 stabilizes, as a result of which the ignition process of the arc 15 is completed and the selected welding process can be started. Of course, it is possible that the backward movement is ended when the short circuit is canceled and thus a forward movement of the welding wire 13 is built up. The two times 36 and 37 described above would then coincide.

After the arc 15 has been formed, an arc voltage 39 is established between the welding wire 13 and the workpiece 16, the voltage curve of which is monitored by the control device 4. At the same time, the welding current 40 required for the welding process is supplied via the power source 2 in a process-dependent, preset order of magnitude. In the illustrated embodiment in Fig. 5 a current curve with a welding current 40 kept constant is shown, ie that, for example, a welding current 40 applied to the welding wire 13 is kept constant over the entire welding process carried out.

From the point in time 38, the welding wire 13 is moved in the direction of the workpiece 16, for example at a constant, maximum, preset feed rate in accordance with the curve 41. During this phase, the welding wire 13 is melted and a metal drop is formed at the end of the welding wire, which is transferred into the weld pool by the surface tension in the weld pool, with a short circuit being formed during the transition, as shown at a point in time 42, ie, that the welding wire 13 touches the surface of the workpiece 16 with the molten metal drop. The control device 4 can recognize this because, corresponding to the curve 43 in FIG. 4, the arc voltage 39 that has built up on the welding wire 13 collapses.

By monitoring the arc voltage 39, when the short-circuit condition occurs in the control device 4, a control process for reversing the drive device 29 of the feed device 11 for the welding wire 13 is generated, through which the drive 32 causes the welding wire 13 to move backwards according to the curve 44, as shown in FIG. 3 shown from time 42, performs. This backward movement is continued until the short circuit condition is eliminated, i.e. the welding wire 13 detaches from the surface of the molten bath and thus the arc 15 is re-ignited, whereby the arc voltage 39 is thereby reduced from a point in time 45 of the elimination of the short circuit condition adjusts again.

During this backward movement, i.e. from time 42 onwards, the preset current curve, in particular welding current 40, is retained, i.e. when the short circuit is formed there is no current increase for the melting of the short circuit, as is known from the prior art in welding processes , is carried out. This ensures that a spatter-free detachment of the metal droplet from the welding wire 13 can be ensured.

The detachment of the metal droplet takes place in the method according to the invention in such a way that the short circuit, i.e. the contact of the molten metal droplet with the weld pool, pulls it into the weld pool due to the surface tension of the weld pool, with the backward movement of the welding wire supporting the detachment of the metal droplet from the welding wire end and thus a more rapid detachment of the metal drop is effected. If the metal drop has detached itself from the welding wire end, the short circuit is canceled and a new arc 15 is ignited automatically, as can be seen at time 45. Thereupon again a reversal movement of the welding wire 13 takes place, ie the welding wire movement is reversed from the backward movement into a new forward movement until a short circuit occurs again, so that the steps described above are repeated.

This type of droplet detachment, in particular the metal droplet, ensures that a welding process for an ignition and a welding process is created which is completely spatter-free and post-treatment of the surface of the workpiece 16 can thus be dispensed with. By the backward movement of the welding wire 13 it is achieved that so that the

AT 409 832 B

State short circuit is canceled without having to make a corresponding increase in current to detach the metal drop. In the exemplary embodiment described, this is mainly a so-called short-arc welding, in which the material is transported in the short-circuit phase of the arc 15. However, it is also possible to use this welding method for other welding processes.

A significant advantage is achieved with this welding process that relatively small welds can now be made completely spatter-free even with thicker welding wires 13, and so-called micro-welds can be made on very thin metal sheets with thin welding wires 13, for example.

The manner in which the welding current 40 and the feed movement of the welding wire 13 is controlled via the process state can be varied as desired. It is also possible that the welding wire movement is not reversed at the same time as the short circuit is released, but that the welding wire 13 is moved back until a corresponding arc length is established and only then is the forward movement initiated for the further melting of the metal droplet. For example, the welding current 40, as shown schematically in the diagrams in FIGS. 6 and 7, can be pulsed at any frequency and the welding wire 13 moves in the direction of the workpiece 16 at the end of each pulse until the metal drop touches the weld pool. The resulting process state short circuit is then released by a backward movement of the welding wire 14, whereupon stopping the drive device 32 or the reversal of movement in the forward movement of the welding wire 13 a new current pulse is applied.

Another possibility is to reduce the welding current to a lower value during the forward movement of the welding wire 13, for example to reduce the recoil forces that could throw the metal droplets out of the arc 15 with larger welding currents and when using CO2 as a protective gas and thus as a result of the resulting Weld spatter negatively affect the welding result, to eliminate.

In Fig. 6 an embodiment with a pulsed current curve is shown. After completion of the ignition process, the welding current 40 is kept constant over a certain period of time 46 at a preset current level, so that a corresponding metal drop can form at the welding wire end.

Since, for example in a robot welding system, the distance between the welding torch 10 and the surface of the workpiece 16 is constant, the individual short-circuit times are known, so that, for example, the welding current 40 is lowered before a short circuit is formed. So that the individual short-circuit times can be determined, it is possible that a corresponding test weld is carried out first, so that the control device 4 can detect and store these times. Of course, if the distance between the welding torch 10 and the surface of the workpiece 16 is known, the control device 4 can calculate these times on the basis of the preset wire feed speed, so that the control device 4 again determines the length of the time 46 for lowering the welding current 40 before the short circuit can.

In the welding method shown in FIG when the short circuit occurs between the welding wire 13 and the workpiece 16, the welding current is reduced. In this welding method shown, the welding current 40 is now kept constant at a corresponding welding current level during the forward movement over a certain period of time 46, with a reduction to a correspondingly lower value after this period of time 46 has elapsed. The welding current 40 is then kept constant at this lower value until the arc 15 is re-ignited, that is to say that a constant welding current 40 is maintained when the short circuit occurs and the subsequent backward movement occurs.

It is of course possible for the higher welding current 40 to be maintained until a short circuit occurs and then a reduction to the predetermined lower welding current value can be carried out.

AT 409 832 B

The advantage of such a method with a pulsed welding current 40 is that the heating of the welding wire 13 can be kept low, since a considerable current load acts on the welding wire 13 only over a certain period of time 46.

FIG. 7 again shows a welding process in which the welding current 40 is applied to the welding wire 13 in the form of a pulse, as is described in FIG. 6. In this method, however, a further current pulse 47 is formed in the backward movement of the welding wire 13, that is to say after the formation of the short circuit. This current pulse 47 has the task of supporting the detachment of the metal droplet, that is to say that due to this current pulse 47 a constriction is formed during the backward movement, so that the metal droplet can be detached from the welding wire 13 more easily and more quickly. It is possible that the height of this current pulse 47 is freely adjustable. The height of this current pulse 47 is chosen such that no metal droplet detachment occurs with a corresponding welding wire diameter.

The formation or application of a Stromipulse 47 in the backward movement has the effect that additional energy is introduced into the metal droplet so that no cooling or additional softening of the metal droplet is carried out, which leads to an even easier detachment of the metal droplet. Furthermore, it is achieved that the backward movement is minimized by the current pulse 47, that is to say that the welding wire 13 no longer has to be moved so strongly backward.

Basically, it should be said of the individual methods shown in FIGS. 3 to 7 that, not as known from the prior art, after the ignition of the welding current 40, a constant forward movement of the welding wire 13 is carried out, but that after a short circuit has formed Forward movement is interrupted and reversed into a backward movement. It is also possible that the forward movement is only interrupted, i.e. that the wire feed is stopped for a certain period of time, i.e. no backward movement is carried out and thus metal droplets are detached due to the applied welding current 40 and the surface tension of the weld pool.

The regulation of the method described above can also be achieved in such a way that, for example, the wire feed speed is chosen arbitrarily and a corresponding current regulation or vice versa is carried out, that is, that the speed of the forward and / or backward movement can be regulated as a function of the current or vice versa. This is possible because the control device 4 can recognize the states of the short circuits and can thus carry out a corresponding regulation of one of the two parameters, in particular the speed or the current. This makes it possible for the short-circuit frequency to be regulated or fixed. As a result of this control option, it is also not necessary for the wire feed speed to be fixed or adjusted or regulated.

This makes it possible that the frequency of the forward and / or backward movement of the welding wire 13 is synchronous or a-synchronous and time-delayed to the welding current 40 given by the power source 2 or that the welding current 40 is synchronous or a-synchronous and delayed in time Frequency of the forward and / or backward movement of the welding wire 13 is applied to the welding wire 13.

8 shows the feed device 11 consisting of the storage drum 14 with the welding wire 13 and the conveyor rollers 30, 31 with the drive 32. In order to achieve an exact guidance of the welding wire 13, the conveyor rollers 30, 31 are provided with circumferential guide grooves 48, 49. A brushless, current-operated servomotor 50, in particular, is suitable as the drive 32 for the rapid change in the direction of rotation required for the welding process described above to bring about the forward or backward movement of the welding wire 13.

In FIG. 9, a further embodiment of the feed device 11 for the welding wire 13 is shown. This is formed in the manner of a linear slide device 51 known from the prior art, which is equipped with gripping arms 52 for grasping the welding wire 13 and which can be moved in opposite directions on a slide arrangement 53 and alternately tension and move the welding wire 13 during the feed movement and with what a rapid reversal of the direction of movement is also possible.

The drive 32 for feed devices 11 embodied in this way can be operated both electrically via linear motors and via drive elements, for example Zylin8, which are acted upon by a pressure medium

AT 409 832 B of 54, are operated.

Of course, according to the invention, a combination is also possible in which a roller drive 55 is arranged on a slide device 56 which can be rapidly reversed in its direction of movement, the slide device 56 being moved for a sensitive movement, for example via a spindle drive 58 operated by a servo motor 57, as shown in FIG 10 is shown schematically. In this embodiment, the direction of rotation of the drive 32 does not need to be reversed, since the direction of movement of the welding wire 13 is reversed by the spindle drive 58. It is also possible that the drive 32 of the linear slide device 51 is formed by an eccentric drive.

A further embodiment of the welding device 1 according to the invention is shown in FIG. 11 on the basis of a schematic diagram. The welding device 1 fed by the energy source 33 has the power section 3 with the power source 2, the control device 4, the feed device 11 for the welding wire 13 and the supply lines 17, 18 and the welding torch 10 for carrying out the welding process on the workpiece 16. In a supply circuit 60 formed by lines 59 for the drive 32, a switching means 61, for example for reversing the drive 32, for example the servomotor 50, is provided. Furthermore, the control device 4 has a control circuit 63 which is formed by a setpoint / actual comparator 62 and which is acted upon by an evaluation circuit 64 which detects the arc voltage. The evaluation circuit 64 and the target / actual comparator 62 form, with the control circuit 63, a diagnostic circuit 65 for actuating the switching means 61. In the evaluation circuit 64, the voltage change at the arc 15 is permanently determined, with the voltage change in a predetermined time unit preferably using a timing element 66 is determined and is based on a control function in the diagnostic circuit 65. It is now possible to control the drive 32 of the feed device 11 as a function of the change in voltage of the arc 15 and as a function of stored parameters of the target / actual comparator 62 and to convey the welding wire 13 in the direction of the workpiece 16 at a controlled feed rate. When a voltage drop is detected, countermeasures are possible by reversing the drive 32 and thus reversing the movement of the welding wire 13 in fractions of a second, effectively avoiding a short-circuit condition with its negative effects such as sticking of the welding wire 13 to the workpiece 16 or weld spatter.

The design of the device that moves the wire electrode forwards and / or backwards can be carried out in all conceivable ways and does not limit the scope of the invention.

For example, the wire can be driven by means of two rollers which have a groove in which the wire is guided. These rollers are driven, for example, by a brushless servo motor that is specified for very rapid changes in the direction of rotation.

Furthermore, a drive by means of a gripping mechanism or a roller drive which is mounted on a slide would be conceivable, the changes in direction of the wire electrode, in particular the welding wire, taking place via the slide.

In the exemplary embodiments described, the wire drive unit should be located very close to the welding torch, in particular to the welding torch tip, since at greater distances the movement at the welding torch tip is delayed due to the play in the wire feed core and therefore no longer correspondingly fast to the Process state can be responded to.

However, the wire feed movement, i.e. the forward and / or backward movement, can also take place through the relative movement of the welding torch 10 to the workpiece 16, which is fastened, for example, to a linear slide, in which case the wire feed control then moves the welding wire forward at a constant speed, i.e. in Direction of the workpiece 16 or the weld pool, can promote and the wire drive does not have to be located directly at the welding point. In this case, too, the wire drive does not need to be able to perform any backward movement.

It must also be stated that the previously described process sequence according to the invention as well as the device according to the invention both in a manual welding process as well as mechanically carried out welding processes, for example in particular on welding robots

AT 409 832 B tern, are applicable. Finally, it should be pointed out that in the exemplary embodiments described above, individual parts have been shown disproportionately enlarged in order to improve the understanding of the solution according to the invention. Furthermore, individual parts of the previously described combinations of features of the individual exemplary embodiments in conjunction with other individual features from other exemplary embodiments can also form independent solutions according to the invention.

Above all, the individual in FIGS. 1; 2; 3, 4, 5, 6, 7, 8, 9; 10, 11 form the subject of independent solutions according to the invention. The related tasks and solutions according to the invention can be found in the detailed descriptions of these figures.

List of reference symbols

<td> 1</td><td>welding machine</td><td> 41</td><td>Curve progression</td>

<td> 2</td><td>Power source</td><td> 42</td><td>time</td>

<td> 3</td><td>Power section</td><td> 43</td><td>Curve progression</td>

<td> 4</td><td>Control device</td><td> 44</td><td>Curve progression</td>

<td> 5</td><td>Switching element</td><td> 45</td><td>time</td>

<td> 6</td><td>Control valve</td><td> 46</td><td>Duration</td>

<td> 7</td><td>supply line</td><td> 47</td><td>Current pulse</td>

<td> 8</td><td>gas</td><td> 48</td><td>Guide groove</td>

<td> 9</td><td>Gas storage</td><td> 49</td><td>Guide groove</td>

<td> 10</td><td>Welding torch</td><td> 50</td><td>Servo motor</td>

<td> 11</td><td>Feed device</td><td> 51</td><td>Linear slide device</td>

<td> 12</td><td>supply line</td><td> 52</td><td>pliers</td>

<td> 13</td><td>welding wire</td><td> 53</td><td>Slide arrangement</td>

<td> 14</td><td>Storage drum</td><td> 54</td><td>cylinder</td>

<td> 15</td><td>Electric arc</td><td> 55</td><td>Roller drive</td>

<td> 16</td><td>workpiece</td><td> 56</td><td>Slide device</td>

<td> 17</td><td>supply line</td><td> 57</td><td>Servo motor</td>

<td> 18</td><td>supply line</td><td> 58</td><td>Spindle drive</td>

<td> 19</td><td>Cooling circuit</td><td> 59</td><td>management</td>

<td> 20</td><td>Flow monitor</td><td> 60</td><td>Supply circle</td>

<td> 21</td><td>Coolant tank</td><td> 61</td><td>Switching means</td>

<td> 22</td><td>Input and / or output device</td><td> 62</td><td>Target / actual comparator</td>

<td> 23</td><td>Hose package</td><td> 63</td><td>Control loop</td>

<td> 24</td><td>Connection device</td><td> 64</td><td>Evaluation circuit</td>

<td> 25</td><td>Strain relief device</td><td> 65</td><td>Diagnostic circuit</td>

<td> 26</td><td>casing</td><td> 66</td><td>Timer</td>

<td> 27</td><td>Control line</td><td></td><td></td>

<td> 28</td><td>Control line</td><td></td><td></td>

<td> 29</td><td>Drive device</td><td></td><td></td>

<td> 30</td><td>Conveyor rollers</td><td></td><td></td>

<td> 31</td><td>Conveyor roller</td><td></td><td></td>

<td> 32</td><td>drive</td><td></td><td></td>

<td> 33</td><td>Energy source</td><td></td><td></td>

<td> 34</td><td>time</td><td></td><td></td>

<td> 35</td><td>time</td><td></td><td></td>

AT 409 832 B

time

time

time

Arc voltage

Welding current