Method for manufacturing sheet metal blanks, in particular hybrid sheet metal blanks

Method for manufacturing sheet metal blanks, in particular hybrid sheet metal blanks, a first sheet metal part being manufactured from a first sheet metal part material, a second sheet metal part being manufactured from a second sheet metal part material, an elongate connecting sheet metal strip being provided, and the connecting sheet metal strip being connected along a first longitudinal edge to the first sheet metal part by a thermal joint, and the connecting sheet metal strip being connected along a second longitudinal edge to the second sheet metal part by means of a preferably thermal joint, characterized in that, in a first process step, the connecting sheet metal strip is connected to the first sheet metal part and, in a second process step, the connecting sheet metal strip is connected to the second sheet metal part, the first and the second process steps taking place within a production line.

This application claims the benefit under 35 USC § 119(a)-(d) of German Application No. 10 2015 101 141.7 filed Jan. 27, 2015, the entirety of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a method for manufacturing sheet metal blanks, in particular, hybrid sheet metal blanks.

BACKGROUND OF THE INVENTION

In industrial applications, in particular, the automotive sector, ever-increasing requirements are being imposed for the combination of the most diverse materials. Sheet metal materials, in particular, have a considerable role to play in this respect. Combinations of light alloy and steel are not uncommon in this context, since different requirements are expected of the different component parts of a sheet metal blank, for example, in terms of its deformability and stability. The ability to connect together different sheet metal materials from different groups of materials, for example, steel and aluminum, albeit by no means straightforwardly, calls for the use of elaborate methods of connection, for example, riveting, crimping or overlapping with third materials, which involves additional processing, handling and, above all, material costs and space requirements.

Familiar from the prior art in DE 10 2008 036 435 B4 is a method for manufacturing a semi-finished material having the ability, as an endless hybrid strip, to connect together materials from different groups of materials. However, a disadvantage associated with the prior art is that an additional cost is involved in order to manufacture, cut to length and convey the semi-finished material for processing with further semi-finished materials.

SUMMARY OF THE INVENTION

The object of the present invention is thus to make available a method for manufacturing sheet metal blanks, in particular, hybrid sheet metal blanks, which is capable of being executed in a simplified and cost-effect manner and avoids additional handling costs.

The present invention relates to a method for manufacturing sheet metal blanks, in particular, hybrid sheet metal blanks, a first sheet metal part being manufactured from a first sheet metal part material, a second sheet metal part being manufactured from a second sheet metal part material, an elongate connecting sheet metal strip being provided, and the connecting sheet metal strip being connected along a first longitudinal edge to the first sheet metal part by means of a preferably thermal joint, and the connecting sheet metal strip being connected along a second longitudinal edge to the second sheet metal part by means of a preferably thermal joint.

The present invention is characterized in that in a first process step, the connecting sheet metal strip is connected along the first longitudinal edge to the first sheet metal part by means of a thermal or mechanical joint, in particular, by means of a laser welding process, and in a second process step, the connecting sheet metal strip is connected along the second longitudinal edge to the second sheet metal part by means of a thermal or mechanical joint, in particular, a laser welding process, the first and the second process steps taking place within a production line.

What this means according to the present invention is that all the connection steps necessary for the provision of a sheet metal blank are realized within a single production line. According to the underlying concept of the method, it makes no difference whether the first and the second sheet metal part originate from different groups of materials or belong to a single group of materials. The connection of the sheet metal parts within the production line (in-line) permits greater cost-efficiency, since handling apparatuses and the time associated therewith in conjunction with handling no longer apply.

In an advantageous further development, it is proposed that at least the first sheet metal part and/or the connecting sheet metal strip are supplied to the production line as an endless strip (coil) and are connected to one another with a continuous feed or with a synchronized feed.

The supply as an endless strip, generally referred to as a “coil”, offers the advantage that handling operations, separation operations and stacking devices are again no longer necessary. In addition, both a continuous feed can be realized, for example, by the arrangement of a strip storage device (“loop” or the like), for example, when changing the coil, or a synchronized mode of operation may be preferred. The latter, synchronized mode of operation is particularly appropriate when separation operations or stacking operations must be undertaken, in which the resulting sheet metal blanks must remain in a single position.

According to the previous example, it is further proposed advantageously that the second sheet metal part is supplied to the production line as an endless strip (coil) and is connected to the connecting sheet metal strip with a continuous feed or with a synchronized feed.

An appropriate embodiment of the method for manufacturing hybrid sheet metal blanks is characterized in that the second sheet metal part material is a different sheet metal part material from a different group of materials than the first sheet metal part material and is not able to be connected to it directly by a thermal joint, the connecting sheet metal strip being configured as a hybrid connecting sheet metal strip having a first wing made of a material capable of being connected to the first sheet metal part material by means of a thermal joint and a second wing made of a material capable of being connected to the second sheet metal part material by means of a thermal joint, and, in a single process step, the first sheet metal part being connected to the first wing of the hybrid connecting sheet metal strip and/or the second sheet metal part being connected to the second wing of the hybrid connecting sheet metal strip respectively by a thermal joint, in particular, by laser welding.

The connection of two sheet metal parts from different groups of materials by means of a hybrid connecting sheet metal strip is thus made possible within a single production line, the hybrid connecting sheet metal strip exhibiting wings made from the corresponding group of materials in each case, which wings are capable of being connected to the respective groups of materials of the sheet metal parts by means of a thermal joint, in particular by laser welding. In this way, hybrid sheet metal blanks can be manufactured with sections of different groups of materials in a continuous production process.

A further development of the method proposes that, in one process step, the first sheet metal part is connected with a butt joint to the first wing of the hybrid connecting sheet metal strip, and in that, in a following process step, the second sheet metal part is connected with a butt joint to the second wing of the hybrid connecting sheet metal strip.

Connections with a butt joint offer the advantage that no additional application of material takes place in the sheet material thickness of the resulting part and the further processing of the sheet metal blanks is not hindered thereby.

As an alternative, one embodiment of the invention proposes that the first sheet metal part, in one process step, is connected with an overlap to the first wing of the hybrid connecting sheet metal strip, and in that the second sheet metal part, in a subsequent process step, is connected with an overlap to the second wing of the hybrid connecting sheet metal strip.

Connections with an overlap offer the advantage that simplified manufacturing can be used, in particular when there is a requirement to introduce reduced costs into the component positioning and/or the edge preparation.

In a further development it is proposed, furthermore, that the first or the second sheet metal part is connected with a butt joint to the hybrid connecting sheet metal strip, and in that the other of the two sheet metal parts is connected with an overlap to the hybrid connecting sheet metal strip.

The advantages described above are combined in this way, and are united within a single sheet metal blank.

An additional advantage derives from the fact that the connecting sheet metal strip is manufactured in a preceding process step from at least two wing strips, the manufacture taking place in particular in a thermal jointing process and/or a mechanical forming process within the production line.

As soon as the connecting sheet metal strip has been manufactured and processed within the same production line, the production line is a fully closed production line starting from the raw material, preferably in the form of endless strips (coils), which delivers the sheet metal blanks or the hybrid sheet metal blanks as the product, without the need to perform intermediate processes and/or handling operations.

In particular, it is proposed, preferably, that at least one sheet metal part and/or the connecting sheet metal strip is subjected to processing, in particular edge processing, ablation, cutting, forming or notching, within the production line before or after the execution of a thermal or mechanical joint.

Edge processing for the purpose of preparing the thermal joint or processing of the other edges (cutting to size), or of the surface of the individual parts to be connected together, further augment the production depth of the production line and increase the efficiency of the method according to the invention.

A further development in addition proposes that the first and/or the second sheet metal part are connected to the connecting sheet metal strip, and in that the resulting endless metal sheet is then parted within the production line in such a way that an individual sheet metal blank resulting herefrom comprises at least one first sheet metal part section, at least one second sheet metal part section and a connecting sheet metal strip section connecting these sheet metal part sections.

The resulting blanks can be made available for the next processing operation (forming, coating, . . . ), where applicable with the additional application of stacking beads or the like. This decoiling also makes it possible to make available sheet metal blanks, which may possibly no longer be capable of being coiled or presented in some other way, for example, due to the absence of flexibility or because of the structure produced in the surface of the sheet metal blanks.

The expression “a group of materials” is used in the context of the invention to denote a group of materials, between which a thermal joint can be produced without problem. In this respect, for example, steel alloys thus constitute a group of materials, or aluminum alloys constitute a group of materials.

The expression “a sheet metal part” is used in the context of the invention to denote a sheet metal blank or an endless metal sheet or a sheet metal strip (coil). According to one particular variant embodiment, the expression “a sheet metal part” used in the context of the invention is also understood to denote a formed and, in particular, a deep-drawn sheet metal blank, or a sheet metal blank or a sheet metal strip, which already exhibit recesses or notches produced by previous process steps.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1depicts in detail a production line1, in which the materials are supplied in the form of endless strips (coils). The connecting sheet metal strip2is made available as a coil3on an axis4, and is supplied from there to the production line in the direction of feed5. The first sheet metal part6is likewise supplied to the production line1in the form of a sheet metal strip from a coil7, and is wound around an axis8, in a direction of feed9arranged parallel to the direction of feed5. Accordingly, the second sheet metal part10in the form of a sheet metal strip is also supplied from a coil11around an axis12in the direction of feed13. Continuing in the direction of feed5,9,13and arranged after the coils3,7,11, are laser welding heads14and15, which produce the welding seam16,17for making the sheet metal blank available. The laser welding head14in this case connects the first sheet metal part6to the connecting sheet metal strip2, in the present case in a continuous feed with the welding seam16. The laser welding head15accordingly connects the second sheet metal part10to the connecting sheet metal strip2in order to make the welding seam17available. Arranged downstream of the connection step in the production line1is a decoiling station20, which then makes the resulting sheet metal blank21available as an individual component. A strip storage device (“loop”), which permits synchronized decoiling, may possibly be located upstream of the decoiling station20, although this is not represented in the present case, without the requirement for the continuous manufacturing of the welding seam16,17to be similarly synchronized. Other suitable arrangements of known strip storage devices, for example after the coils have been made available, are also conceivable.

FIG. 2depicts an alternative embodiment of a production line30corresponding to the production line inFIG. 1, in which the connecting sheet metal strip31is now proposed as a hybrid connecting sheet metal strip. The first sheet metal part material32and the second sheet metal part material33now consist of materials from different groups of materials and are supplied to the production line30. The supply takes place accordingly via coils34and35. The hybrid connecting sheet metal strip31is supplied to the production line30via a coil36.

The hybrid connecting sheet metal strip31has a first wing40and a second wing41, each of which consists of materials from different groups of materials. The material group of the first wing40corresponds to a material group of the sheet metal part32and is thus capable of being connected to the first sheet metal part32by means of a first laser welding head50for making available a first welding seam53, while making available a thermal joint. Correspondingly, the material group of the second wing41of the connecting sheet metal strip31of the material group of the second sheet metal part33is selected accordingly, so that the second welding seam52can be made available by means of the second laser welding head51.

Decoiling45for the purpose of making available a hybrid sheet metal blank46, which can then be supplied for further processing, also takes place in the region of the production line30according toFIG. 2.

In a preferred, although only schematically represented embodiment, it is proposed that at least one sheet metal part32or33, although also, where appropriate, both sheet metal parts and/or the hybrid connecting sheet metal strip, may have undergone previous processing operations. Recesses48may be provided in this case, for example. Edge processing, cutting to size or other processing possibilities are also conceivable.

FIG. 3adepicts a further embodiment of a production line100according to the invention for making available a hybrid sheet metal blank101. The production line100has at its center a hybrid connecting sheet metal strip102, which is supplied as an endless strip in the form of a coil103on an axis104of the installation in the direction of feed105.

A first sheet metal part110made of a metal sheet from a first group of materials is supplied to the production line100, furthermore, and is arranged on the connecting sheet metal strip102. The arranged first sheet metal part111is then displaced in the direction of feed105to a first laser welding head112, which connects the first sheet metal part111to a first wing113of the hybrid connecting sheet metal strip102by means of a first welding seam114. The first wing113of the hybrid connecting sheet metal strip102in this case corresponds to the group of materials of the first sheet metal part110,111, so that a thermal joint in the form of a laser-welded joint is made possible.

The second sheet metal part120is arranged correspondingly on a second wing121of the hybrid connecting sheet metal strip102. The arranged second sheet metal part122is then supplied accordingly in the direction of feed105to a second laser welding head123, which produces a welding seam124between the second wing121of the hybrid connecting sheet metal strip102and the arranged second sheet metal part122. Continuing in the direction of feed105, decoiling130according to the description of the above Figures is then also undertaken, as a result of which the hybrid blank101is made available individually. Here, too, a possible strip storage device is not represented in the present case.

It is also depicted by way of example inFIG. 3a, although not exclusively or restrictively, that a recess140or processing of some other kind may be proposed, for example, in the first sheet metal part110,111. The geometry of the edge line outside the welding seam114,124of the first sheet metal part110and/or of the second sheet metal part120can also be freely selected for processing in the production line100.

Represented inFIG. 3bis an alternative illustrative embodiment of the production line according toFIG. 3a, which positions sheet metal parts110,111on one side only. Identical components are provided with identical reference designations to those inFIG. 3a. Reference is made to the above description.

Various embodiments of the connections of sheet metal parts to the connecting sheet metal strip are represented inFIGS. 4a, 4b, 4cand4d.

FIG. 4adepicts a thermal joint in the form of welded seams114and124of a first sheet metal part111positioned with a butt joint on a first wing113of a hybrid connecting sheet metal strip102, and of a second sheet metal part122on a second wing121of the connecting sheet metal strip102. The connecting sheet metal strip in this case is likewise produced by means of a fusible joint130from the materials of different groups of materials and, where appropriate, is formed into the resulting longitudinal strip by a roll-cladding process.

FIG. 4bdepicts a variant of the connection of the first sheet metal part140with a butt joint by means of a welded seam141to a first wing142of a hybrid connecting sheet metal strip143. The second wing144of the connecting sheet metal strip143is in turn attached with a butt joint to a second sheet metal part146by means of a welded seam145. The hybrid connecting sheet metal strip143in this case is manufactured as the overlap between two wing strips142and144, and these are connected to one another by means of a fusible joint147. A mechanical joint, such as a positively locking deformable joint, a crimped joint or a riveted joint, can be proposed as an alternative to the fusible joint.

FIG. 4cdepicts a variant of the connection of the first sheet metal part150to a first wing152of a first hybrid connecting sheet metal strip153with an overlap by means of a mechanical joint151, such as a positively locking deformable joint, a crimped joint or a riveted joint. The second wing154of the connecting sheet metal strip153is in turn attached with a butt joint to a second sheet metal part156by means of a welded seam155. The hybrid connecting sheet metal strip153in this case is embodied according toFIG. 4a. It will be obvious to a person skilled in the art that the second sheet metal part156could also be similarly mechanically attached.

FIG. 4ddepicts a thermal joint attached with an overlap in the form of welded seams161and165of a first sheet metal part160on a first wing162of a hybrid connecting sheet metal strip163, and of a second sheet metal part166on a second wing164of the connecting sheet metal strip163. The connecting sheet metal strip in this case is likewise produced by means of a fusible joint167from the materials of different groups of materials and, where appropriate, is formed into the resulting longitudinal strip by a roll-cladding process.

It is clear, furthermore, that the variants inFIGS. 4ato 4dare also universally applicable. The advantage according to the invention is achieved by the manufacture of the connections concerned within a production line.

LIST OF REFERENCE DESIGNATIONS