Schweissverfahren und laser-hybrid-schweissbrenner

The invention concerns a procedure for welding coated sheet metals by means of a laser hybrid welding process, whereby at least a laser process and an inert gas welding process are accomplished, whereby by way of the inert gas welding process a welding-rod materials is supplied to the welded joint. Further the invention concerns a laser hybrid torch to welding coated sheet metals and/or construction units with a laser and/or a laser optics, and at least an inert gas unit and a wire promotion device for a welding-rod materials and/or a filler rod. There is already procedures for welding coated sheet metals, which are used for example in the automobile industry, admits. For example the DE describes 101 51 257 A1 a procedure for connecting strained and positioned loose body parts of a vehicle body in a Framingstation, with which the body parts are welded by hybrid welding with at least one laser beam and with at least one arc. Combined laser light sheet welding sets, laser hybrid welding units so called combine the advantages of the laser, like speed and good heat bringing in into the workpiece with the advantages of conventional welding methods, e.g. the MIG (metal lnertGas) welding method, as for example a good gap bridgeableness. For example describe US 2001/0050273 A1, US 2001/0052511 A1, US 2001/0047984 A1, US 2003/0173343 A1 as well as US 2002/0008094 A1 laser hybrid welding method, with which a laser process and an inert gas welding process are accomplished. In some of the documents pointed out that with the laser hybrid welding process workpieces also coated can be welded, it is not dealt however with the problems in quality, which arise by the evaporation of the coating. Procedure is fundamental to mention that in practice for this a joint preparation is necessary, with which a gas evaporation gap and/or a degassing area between the sheet metals be created must to from the conditions the technology admitted, so that the gases developing with the weld can withdraw. Further a rework of the welding seam is in practice usually accomplished to close in order to reach a close welding seam, which is called that after the automated welding process a Nachschweißung is by hand accomplished, in order the developed inclusions, craters or holes. The task of the available invention exists from there in the creation of a procedure for welding coated sheet metals, with which as few ones as possible result to no inclusions, for example from evaporation of the coating. A task of the invention lies also in the fact that the welding seam exhibits a necessary stability and tightness. A further task of the invention is to minimize and/or even eliminate the preparation time and/or the Vorbearbeitung because of the sheet metals which can be welded, so that no welding seam preliminary work are necessary. A further task of the invention lies in the creation of a welding process, with which essentially less energy and/or warmth into the VV rl. ÷; '.l. ; sparkling. -- l. --.r.--. , 4;. -. r l. -- k; h h÷; . I is solved the task according to invention in procedure-moderate regard by the fact that the coated sheet metals are positicniert essentially gap-free, thus with a gap of zero and/or almost zero between the sheet metals, to each other and that as welding-rod materials for the inert gas welding process a filler rod with Zinkund is used/or Kohlenstoffund/or aluminum content. The advantage is in the fact that due to the employment of a certain welding-rod materials in combination with a laser hybrid welding process a welding seam without inclusions is made possible, whereby on the one hand tightness of the welding seam and on the other hand a high stability of the welding seam are reached. A further advantage results 3 RK 413,667 B from the fact that the welding process taken place in a job and thus a rework of the welding seam no longer is necessary. It must take place thus no additional welding process, for example by hand, after the weld more, in order to ensure an appropriate stability and tightness, how this is with the state of the art the case. Thus substantial saving of time will know reached and accordingly also the costs to be lowered. It is of advantage in addition, that the sheet metals which can be welded do not have to be roughed out, since first no so-called evaporation gap must be created and the sheet metals is held only in an unfinished way one above the other, whereby again in simple way Zeitund cost saving is reached. Thus will it also possible to accomplish a fully automated welding of sheet metals and/or construction units as this is desired for example in the automobile industry. A measure, with which the sheet metals exhibit a zinc coating, and a filler rod are used, which prefer the components zinc, carbon and aluminum exhibit, or a filling wire with the designation SAF DUAL ZN® is used, is of advantage, since thereby the filler rod with the sheet metal harmonizes, in particular with the coating of the sheet metal and thus inclusion-free also into the welding seam merges arising steams of the coating, so that a close welding seam without rework in a work procedure can be created. The sheet metals favourable-proves one above the other positioned and pressed over a tightener against each other, whereby it is reached that the sheet metals before the weld are positioned in the tightener accurately and firmly, so that the welding process can be accomplished after the positioning and restraint of the sheet metals problem-free, without for example one of the sheet metals is slipped and thus the welding result is impaired. A measure, in which as inert gas welding process a MIG/MAG Schweißprozess is used, is of advantage, since thereby cheap and torches well-known from the state of the art into combination with the laser unit and/or with the laser can be used. A very good welding process is used by the use of a MIG/MAG Schweißprozesses for bringing in and/or supplying welding-rod materials and/or filler rods, so that very good welding results can be obtained. In addition, a measure, in which the MIG/MAG Schweißprozess is formed by a cold metal transfer welding process, is of advantage with which a pre/a backward motion of the filler rod is accomplished, whereby the energy bringing in is reduced over the inert gas welding process, since drop-replace due to the backward motion of the filler rod effected, since thereby a very narrow welding seam can be formed. A further advantage is in the fact that due to the small heat bringing in the delay of the sheet metals can be substantially minimized. From a measure, in which the energy of the laser process of the plate thickness, and/or which it is adapted to requirements of the weld the advantage results that the laser process only the energy needed for the welding method is lost used and thus no unnecessary energy. A measure is of advantage with that the laser process is in such a manner adjusted that the focus of the laser is because of the surface first sheet metal seen from the laser. Thus reached that the laser and/or the energy and/or the intensity of the laser at the surface of the sheet metal are bundled and thus in that place of the weld, at which the largest energy is needed for melt opens of the sheet metal also it is used. A measure, in which the inert gas welding process is at the same time activated and/or deactivated with or after the laser process, is of advantage, since thereby in simple way the start of the inert gas welding process is regulated to the laser process and the 4 RKs 413,667 B inert gas welding process is started not inadvertently and/or uncontrolled before or after the laser process. Thus further a certain security is ensured and by unintentional igniting of the laser and/or the inert gas welding process prevented the injury risk and also the destruction risk in simple way. A further measure, in which the sheet metals are positioned one above the other and by means of arranged a tightener at the Schweißkopf are against each other pressed and which is formed tightener from a role and a clamp, which are arranged at laser-hybrid the torch, is by advantage, since thereby in favourable way an external tightener is no longer necessary. A further advantage is in the fact that the sheet metals are only pressed against each other due to the tightener arranged at laser-hybrid the Schweißkopf in the direct range of the weld, so that particularly in the welding range no and/or almost no gap between the sheet metals present is. Favourable way becomes the laser unit from one from the state of the art admitted Eximerlaser (e.g. ArF, KrF, XeCl), solid laser (e.g. ruby, lp: YAG, lp glass), diode laser (ATMs, GaAIAs) or gas laser (CO2) in an educated manner, since thereby more simply and more economically laser-hybrid Schweißkopf can be created. Further favourable arrangements are descriptive in the requirements 11 to 17. Itself the advantages resulting in from it can be inferred from the description and/or from the requirements 1 to 9, described before. The available invention is more near described on the basis the attached designs. In it show: Fig. 1 a schematic representation of a laser hybrid welding head; Fig. 2 current, Spannungsund of motion diagrams of a cold MetalI transfer Schweißprozesses and a current time diagram of a laser process, as well as a plan view on the welded sheet metals in simplified representation; Fig. 3 current, Spannungsund of motion diagrams of a pulse welding process and a current time diagram of a laser process, as well as a plan view on the welded sheet metals, simplifies and schematically represented; Fig. 4 a fillet weld in cut and simplified schematic representation; Fig. 5 a I-seam in cut and simplified schematic representation, welded by means of lasers; Fig. 6 a I-seam in cut and simplified schematic representation, welded in laser-hybrid the welding method; Fig. 7 the starting phase and Fig. 8 the start for the laser hybrid welding process in schematic and simplified representation. In Fig. 1 is simplified and schematically represented a laser hybrid welding head according to invention 1 and/or laser hybrid torch, which for example at a bionic arm 2 is arranged, for welding coated sheet metals 3, how these are used in the automobile industry. The sheet metals exhibit 3 prefer a zinc coating. The laser hybrid welding head 1 is at least an inert gas unit 5 formed from at least a laser unit 4 and. The sheet metals 3 are held unprepared to each other in an unfinished way, and/or. That means that for welding the sheet metals 3 no special preparation and/or treatment must be needed and/or made for the welding seam, in order to exhaust zinc steams for example withdrawing, as this admits from the state of the art is. The sheet metals 3 are arranged simply one above the other, without forming for example a gasification gap for the zinc between the sheet metals 3, as this admits from the state of the art is. Thus in simple way during the preparation of the sheet metals 3 for welding substantial Zeitund cost saving is already reached. The sheet metals 3 thus one above the other and in the position arranged and afterwards for example by tighteners 6 on this position, correct for the weld, gehalAT 413,667 B ten. In the represented remark example the tightener 6 formed from a role 7 is, which at the laser hybrid welding head 1 is arranged and presses in close range of the laser hybrid weld by means of a clamp 8 on the sheet metals 3. The laser hybrid welding head 1 is thus moved after the correct positioning toward the sheet metals 3 up to the contacting of the tightener 6, thus the role of 7. By the role 7 the sheet metals 3 are pressed against each other in the range of the weld, so that approximately gap-free positioning of the sheet metals 3 is reached to each other, thus a gap of zero and/or almost zero mm between the sheet metals 3. Thus the sheet metals 3 are held only within that range, within which it is actually welded to each other, whereby the expenditure of the RST preparations of the sheet metals 3 is naturally minimized for welding substantially. For the laser unit 4 of the laser hybrid welding head 1 everyone can be used from the state of the art well-known lasers, as for example Eximerlaser (e.g. ArF, KrF, XeCl), solid laser (e.g. ruby, lp: YAG, lp glass), diode laser (ATMs, GaAIAs) and gas laser (CO2). The inert gas unit 5 is formed from a MIG/MAG torch for a MIG/MAGSchweißprozess. Naturally also for example a so-called cold metal transfer welding process is in combination with the laser process applicable, as it is described still more exactly in one of the following figures. The laser hybrid welding head 1 is arranged thereby preferentially on a bionic arm 2 of a welding robot, how it is used in the automobile industry, where the sheet metals 3 and/or construction units which can be welded are in two dimensions trained in the rarest cases. With conventional welding methods for zinc-coated sheet metals 3 the weld could not be accomplished by the welding robot the requirements of the user accordingly and it was necessary after the laser weld of the welding robot a further manual weld, in order to ensure the necessary stability and/or tightness of the welding seam. A substantial advantage consists from there of the fact that with the procedure according to invention now the weld can be accomplished in a work procedure, whereby a high firmness and tightness of the welding seam are obtained. The laser hybrid welding head 1, and/or the laser unit 4 and the inert gas unit 5 are for example over two independent hose packages 9, 10, which at least in each case a unit of the laser hybrid welding head 1 with the means, for example river necessary for the respective welding process and tension, coolant, filler rod supply, etc. supplies, connected with a welding set and/or a power source and/or a wire supply, whereby these are not represented in the execution shown. The inert gas unit 5 exhibits further a wire promotion device 11, with which a welding-rod materials, in particular a filler rod 12 is promoted toward the sheet metals 3. Preferred welding-rod materials and/or the filler rod 12 exhibits the components zinc and carbon and aluminum. Favourable way is used as filler rod 12 a filling wire with the designation SAF DUAL ZN®. Naturally it is also possible to use a filler rod 12 with similar welding-rod materials. With the procedure according to invention the employment of a special welding-rod materials and/or filler rod 12 when welding zinc coated sheets 3 is substantial, whereby during the welding process the zinc evaporating from the sheet metals 3 does not have effects on the welding seam 12. This is reached preferentially by the employment of a filler rod 12 with the designation SAF DUAL ZN®. For this it is still substantial that the energy bringing in is to be kept as low as possible over the inert gas welding process, in order to achieve as small a delay and good mechanically technological characteristics as possible. During the welding process the sheet metals 3 by the laser 13 are melted and/or. welded through and solved and/or evaporated the zinc coating of the sheet metals 3. With the following inert gas welding process by bringing in of auxiliary material the laser weld and/or and welded each other the sheet metals 3 closely the mit6 RK 413,667 B are laser-purely filled up and/or locked. In the following parameters and/or attitudes to the illustration and application of the procedure are descriptive. These show only one variant for a certain application, which can be amended for other applications, in particular different sheet metals. For example one receives very 9.ute of welding results, with two-sheet metal connections, in particular with a fillet weld at the Uberlappstoß or a butt weld or a pass seam at lo the overlapping impact, whereby the sheet metal connections between 0,5 and 2 mm galvanized on electrolytically and at hot-dip galvanized sheet metals effected. A focus diameter from 0,4 to 1.4 mm is selected, whereby the distance between focus and impact of welding-rod materials (welding process distance) can amount to 0 to 5 mm. The achievement of the laser PL amounts to between 3 and 4 KW. The attitudes on the power source of the inert gas unit can take place in such a manner: VD (filler rod conveying speed) = 1 to 10 m/min; dD = (filler rod diameters) = 1.0 to 1.2 mm; I (welding current) = between 40 and 260 A. Both two-component gases, and three-component gases for these applications can be used. A two-component gas knows for example from 96% acre 4% 02 or a three-component gas like e.g. DIN EN 439 - M14 (82 VOL. % acre + 14 VOL. % CO2 + 4 VOL. % 02) with deviations from + _ 3% compound its. For the sheet metals 3 most usually-used in the automobile industry for example an attitude of the welding process can take place in such a manner, as described in the two examples 1 and 2 (in it Vs mean the welding speed, VD the wire conveying speed, I the welding current, U the Schweißspannung and PL the laser achievement): Example 1: electrolytic zinc coating ZE75/75 after EN 10152 pass seam at the Uberlappstoss: Filler rod: SAF DUAL ZN® Vs: 3 m/min I: 50A VD: 1.6 m/min U: 12.2 V distance: 2 mm PL: 3.9 KW of focus diameters: 0.8 mm example 2: Z 100 hot-dip galvanized zinc coating: Zinc layer thickness: 7.5 IJm butt weld filler rod: SAF DUAL ZN® vs: 2.4 m/min I: 50A VD: 1.6 m/min U: 12.2 V distance: 2 mm PL: 3.9 KW of focus diameters: 0.8 mm of 7 RKs 413,667 B thereby are obtained very good and above all close welding seams, which in a work procedure, thus during a welding process, over the laser hybrid welding process to be manufactured to be able, without a rework of the welding seam is necessary. Of course the same welding results can be obtained also when change one or several parameters. For example as for example filler rod conveying speed (vs) becomes, welding current amplitude by alteration of cooperating parameters, (I), etc., again obtained the same good welding quality, so that the attitudes only as reference points to be seen to be able. Also it is possible to deposit appropriate routines in a memory of the welding set by which an automatic attitude of the plant can be made. For example the remaining parameters can be determined and stopped automatically, in order to achieve again the optimum welding results on alteration of a parameter by the plant. In Fig. 2 now simplified and schematically represented the temporal operational sequence of the inert gas welding process, in particular a cold MetalI transfer Schweißprozesses is, on the basis a current time diagram 14, a period of tension diagram and a flight time diagram 16. Further the combined laser process is represented in its own current time diagram 17, as well as to the explanation a plan view 18 on and/or the welded sheet metals which can be welded 3. the diagrams of the inert gas welding process are represented not true to scale thereby in relation to the current time diagram 17 of the laser 13, and/or to the plan view 18 of the sheet metals 3. The diagrams serve only for the illustration of the expiration, and/or the temporal succession the Schutzgasschweißung for a part of a welding seam 22, against what with the laser process an illustration of the course is represented for the education of the welding seams 22 on the sheet metals 3. With the beginning laser-hybrid of the welding process at the time 19 the laser 13 by the laser unit 4 is activated, whereby the sheet metals 3 are melted and/or welded through, and evaporated the zinc coating of the sheet metals 3. In close range of the laser 13, thus in welding direction seen immediately after the laser 13, the inert gas unit 5 is arranged. After igniting the laser 13 or with the activating of the laser 13 the starting phase for the ignition of the arc is accomplished at the same time with the inert gas welding process, as the filler rod 12 to one time 21 is thus induced toward the workpiece, the sheet metals 3, according to arrow 20 up to contacting with these. During the contacting of the filler rod 12 with the sheet metals 3 a short-circuit develops. Afterwards an increase of the river I is accomplished in such a manner that melt opens of the filler rod 12 one prevents. By the following retreat of the filler rod 12 toward the arrow 23 an arc 24 is ignited. Such Zündbzw. Starting phase for the arc 24 is well-known also under the term elevator Arc ignition. At the time 25 is Zündbzw. Starting phase for the arc 24 of the inert gas welding process finally and it effected now an increase of the river I and at the same time a forward movement of the filler rod 12 toward the sheet metals 3. via the current increase is formed now at the end of the filler rod 12 a drop 26, which at the time 27 with a recent contacting of the filler rod 12 with the sheet metals 3 and/or. with the melting bath, which by the arc 24 one forms, and which is replaced following backward motion of the filler rod i2. During the inert gas welding process the filler rod 12 accomplishes a constant prebackward motion. Since the replacement of the welding drop 26 without current increase takes place, with this process little energy, is brought in particular heat energy, into the sheet metals 3. Of course the cold MetalI transfer process can be combined also with another well-known welding process, in particular with a pulse welding process, and be accomplished alternating a cold MetalI transfer process and a pulse process with the inert gas welding process. As previously mentioned, the sheet metals 3 from the laser 13 are melted and/or welded through, and solved and/or evaporated further the zinc coating of the sheet metals 3. With the darauf8 RK 413,667 B RST the following inert gas welding process by bringing in of auxiliary material the laser weld is laser-purely filled up and/or locked and/or. Welding-rod materials with as small a energy bringing in as possible is supplied, since the drop transition in the short-circuit without current increase takes place, so that the sheet metals 3 are again closely welded with one another. It is reached by this special welding-rod materials bringing in over the cold MetalI transfer process that the weld bead can be kept very narrow in their width, since over the inert gas welding process only a slight additional melting of the sheet metals 3 is caused. With a retarded start of the inert gas welding process a parameter can be stopped in the welding set and/or in the control device of the welding set. From the entered distance between the laser unit 4 and the inert gas unit 5 and the defined welding speed the temporal delay is computed by the control device and thus the inert gas welding process to the laser 13 is activated automatically and/or deactivated. Fig. a remark example of a laser hybrid process with a laser 13 shows 3 and a pulse welding process, whereby now on the basis a current time diagram 28, a period of tension diagram 29 and a flight time diagram 30 the temporal operational sequence of the inert gas welding process, in particular a pulse welding process is, simplified and schematically represented. Further the laser process is represented in a current time diagram 31, as well as to the explanation a plan view 32 on and/or the welded sheet metals which can be welded 3. here the diagrams of the inert gas welding process are represented thereby again not true to scale to the current time diagram 31 of the laser 13, and/or to the plan view 32 of the sheet metals 3, and show only the expiration, and/or the temporal succession of the Schutzgasschweißung for a part of a welding seam 22, against what with the laser process an illustration of the course is represented for the education of the welding seams 22 on the sheet metals 3. At the time 33 the laser 13 is activated and welded through by this the sheet metals 3 aufgeschmelzen and/or and evaporated the zinc coating of the sheet metals 3. After igniting the laser 13 or with the start of the laser 13 Zündbzw becomes simultaneous. Starting phase of the inert gas welding process accomplished whereby the filler rod 12 to one time 34 toward the workpiece, the sheet metals 3, toward the arrow 20 up to contacting with these is thus induced. During the contacting of the filler rod 12 with the sheet metals 3 a short-circuit develops, whereby an increase of the river I is accomplished in such a manner that melt opens of the filler rod 12 is prevented. By the following retreat of the filler rod 12 toward the arrow 23 the arc 24 is ignited, whereby the filler rod 12 will proceed into a defined starting position. Zündbzw. Starting phase for the inert gas welding process is thus final. As mentions already before, is this Zündbzw. Starting phase also under the term elevator Arc ignition admits. At the time 25, thus after Zündbzw. Starting phase, effected now an increase of the river I and at the same time a continuous forward movement of the filler rod 12 toward the sheet metals 3. at the end of the filler rod 12 forms a drop 26, which at the time 34 from the filler rod 12 becomes detached, whereby replace for example by a current pulse be introduced can. Formed by sinking of the river I and renewed increasing wiederhoit a drop 26 and replaced in temporal Abfoige of the filler rod 12. The Fig. 4 to 6 shows now in simplified and schematic representation different weld shapes in cut side view, whereby in Fig. 5 a welding seam manufactured with a conventional welding method is represented. Naturally all are possible in the welding engineering well-known Nahtfcrmen with the welding method according to invention, however in the description only two different weld shapes are described, since the remaining weld shapes are derivable from this description. 9 RKs 413,667 B in Fig. a cut of a fillet weld 35 is simplified represented 4. The sheet metals 3 are overlapping and gap-free and/or approximately spalffrei, arranged. The laser 13 is directed toward an intersection 36 of the sheet metals 3. The laser energy and/or intensity and the inert gas welding parameters depend thereby on the sheet metals 3 which can be welded, and can be adjusted for example by the user at a laser power source and at the welding set and/or the control device of the welding set. By means of the laser 13 a penetration is accomplished into the sheet metals 3, on which the inert gas welding process following on the laser process 13 pulls a welding seam 37 by means of welding-rod materials, thus the filler rod 12, in form of the fillet weld 35 over the sheet metals 3 and locks thus the laser penetration completely. For the sake of clarity the laser 13 and the filler rod 12 are strichliert represented. The advantage consists of it that the assigned filler rod 12 exhibits a zinc content, by which the zinc coating of the sheet metals 3 is bound and thereby no zinc, to accumulate itself " can. With from the conditions the technology welding methods for zinc coated sheets 3 admitted the zinc before the laser 13 and/or the inert gas welding method, are moved over ", whereby these zinc pads can explode then proverbially. Thus inclusions can and/or. Holes or craters in the welding seam 37 develop, which must later be worked over again with a separate weld, in order to create a close welding seam. With the procedure according to invention against it a stable becomes, and/or by the connection of the zinc. sturdier and close welding seam 37 production. Develop thus no inclusions, holes and/or crater in the welding seam 37 and it a close welding seam in a processing step are thus created. Fig. a remark example from the state of the art shows 5, with which a cut of a I-seam 38, which is welded only with a laser welding process, simplifies, represented. The laser 13 and/or the focus of the laser 3 preferentially directed toward an upper edge 39 and/or surface of the sheet metal 3 resting upon above is. In the represented remark example the laser 13 is only used, how this is usually the case. Due to the zinc coating of the sheet metals 3 a zinc pad before the laser 13 forms during welding by means of the laser 13, from which inclusions 40, holes and/or craters in the welding seam 37 result. Thus the quality of the welding seam 37 is however substantially affected, worsened in particular. Fig. now according to invention a I-seam 38 welded with laser-hybrid the welding method shows 6. The laser 13 is, as in detail descriptive, leading, whereby the focus of the laser 13 is preferentially because of the surface 39 of the first sheet metal 3. By means of the laser 13 the sheet metals 3 are melted and/or welded through, and the following inert gas welding process puts a inclusion-free welding seam 37 over it. This is reached by the fact that welding-rod materials of the filler rod 12 cooperate in favourable way with the coating of the sheet metals 3 and/or the melting bath. Thus an essentially improved welding seam 37 is made possible, with which in a processing step a sturdy and close welding seam 37 is ensured. Fig. 7 and Fig. 8 shows now a starting phase and the start for the laser hybrid welding process, in schematic and simplified representation. At least a laser process becomes with the help of the laser 13 and an inert gas welding process, in particular with Kdl - /Ed t r. , r ". one…. …. AL - S. , hutzgaseinheit 5, accomplished. L, laser 13 leads the Schutzgasschweißùp.rozess, whereby the inert gas welding process is positioned in close range of the laser 13. Uber the inert gas welding process is supplied a welding-rod materials and/or a filler rod 12 to a welded joint. In principle can said that with the start of the laser process, thus if the laser hybrid welding head 1 is in its starting position 46 the focus 47 of the laser 13 into a defined distance 42 is stopped to the surface 41 of the sheet metal 3, on which the laser 13 accomplishes a pre-setable longitudinal movement 44 toward the inert gas unit 5, thus up to a reversal position 48, and afterwards for starting position 46 back 1 0 RKs 413,667 B. During the advance movement of the laser 13, during the longitudinal movement 44, as schematically represented by a double arrow, the laser achievement is thus regulated in such a manner that a coating 45 of the sheet metal 3 is evaporated and/or melted and the surface 41 of on top-lying sheet metal 3 by the laser 13 from impurities and/or coatings is thus released. Favourable way is in such a way selected the distance 42 of the focus 47 of the sheet metal 3 that the laser 13 trains as broad a trace as possible, in particular laser-purely, at the sheet metal 3, whereby this trace serves 43 afterwards for the inert gas welding process as ignition surface, as this RST is described still more exactly below. For this it can be said that with a small distance 42 and/or during an arrangement of the focus 47 at the surface 41 of the sheet metal 3 a narrow is laser-purely created, against what with a larger distance 42 to the surface 41 of the sheet metal 3 a broader laser-purely is reached and/or ignition surface 43. It is to be guaranteed however that the focus 47 is selected in such a way that a melting and/or. Evaporation at least the coating 45 takes place. The laser hybrid welding head 1 accomplishes thus after activation of the laser 13 a pre-setable longitudinal movement 44 toward the inert gas unit 5 and afterwards for starting position 46 back, whereby the laser hybrid welding head 1, in particular the laser 13 and the inert gas unit 5 for better explanation in the starting position strichliert and are dash-dotted represented to the final position of the cleaning method. The laser 13 travels a preset and/or adjustable distance 49 as it were during the longitudinal movement 44. Distance 49 is thereby in dependence distance 50 between lasers 13 and inert gas unit 5 selected, so that during following igniting of an arc 24, with which the laser hybrid welding head 1 is in its starting position 46, this is ignited within the range of the melted sheet metal 3, thus the ignition surface 43, which is called that the laser 13 and/or the laser hybrid welding head 1 accomplishes at least a longitudinal movement 44 up to the inert gas unit 5. However it is also possible, in order to ensure a safe ignition of the inert gas welding process to accomplish the longitudinal movement further 44 as up to the inert gas unit 5 so that it is guaranteed that during an ignition of the arcs 24 within the range of the creative ignition surface 43 one ignites. After the completion of the starting phase, thus if the laser hybrid welding head 1 is in its starting position 46, now the welding process is started, which is called successively the laser process and the inert gas welding process is for example at the same time or introduced. The ignition of the arc 24 on the ignition surface 43 prepared by the laser 13 takes place. Preferred thereby if the distance amounts to 50 between the laser process and the welding process between 0 and 15 mm, prefers between 0 and 6 mm. Here it is possible that also or afterwards to the start of the inert gas welding process the laser achievement is changed at the same time on the preset achievement for the welding process which can be accomplished afterwards. The movement of the laser hybrid torch 1 can be made by a robot. Of course it is also possible that this starting phase can be used also with a hand-guided laser hybrid burner, whereby for this the user accomplishes first the longitudinal movement 44 with the laser process alone and afterwards the hand-guided laser hybrid burner above the creative ignition surface 43 positioned, so that the actual welding process can be introduced.