DE102014001657A1 - Method for folding e.g. metal sheet used for producing outer skin portion for automotive vehicle, involves heating flat edge region of workpiece by applying infrared radiation, and bending heated flat edge region of workpiece - Google Patents

Abstract

The method involves heating (S2) a flat edge region of workpiece by applying infrared radiation, and bending (S4) the heated flat edge region of the workpiece. The workpiece such as metal sheet is made of light metal or light metal alloy such as aluminum or aluminum alloy.

Description

The invention relates to a method for folding a workpiece according to claim 1.

Method of the type discussed here are known. In particular, it is known to edge aluminum sheets for the purpose of seam joints in outer skin components for motor vehicles. It is possible that due to lack of ductility of the workpiece cracks or fractures arise, with a lack of ductility occurs especially when resulting from previous forming processes work hardening of the workpiece. Such cracks or breaks lead to a reject part, which in turn leads to increased costs. This is the case in particular with seam connections, which comprise two sheets. It is further shown that, in particular, 6xxx aluminum alloys for skin applications are limited falzbar, as there are many demands on such aluminum sheets, for example, in terms of strength, the Querrecknarbigkeit, in terms of roping, deep drawing, ironing, and other requirements ,

To improve the folding properties, it is known to heat already folded workpieces in the region of a bending or folding zone before folding. For this purpose, a laser is typically used. This requires a relatively complex system technology to heat the quasi-linear bending zone. Also results in a relatively high total process time to start the necessary areas. The robustness of the heating is limited because, for example, a focus of the laser on the finished folded pressed part by impurities, for example, a corrosion protection or Umformbeölung is disturbed.

From the German patent application DE 10 2009 031 449 A1 is a method for producing an aluminum molded part, in which an aluminum sheet is at least partially heated and then deep-drawn with a thermoforming tool.

The heating of the reduction serves a risk of cracking while improving the formability of the aluminum sheet.

The invention has for its object to provide a method with which the workpiece can be folded process reliable, without resulting in the disadvantages described above.

The object is achieved by providing a method with the steps of claim 1. The method for folding a workpiece comprises the following steps: at least one flat edge region of a workpiece is heated, and the workpiece is folded in the heated, flat edge region, ie in the heated state. By heating any work hardening are at least largely eliminated, and the workpiece is given an improved formability, so that no damage during folding and in a subsequent preferably subsequent folding occur. At the same time, the heating is simplified, since no complex geometries must be traversed, but rather flat areas are heated before edging. In particular, it is possible to choose the areas to be heated geometrically larger than it is the later bending zone itself, whereby the heating is further simplified. Within the scope of the method, it is possible to improve the folding and folding properties, in general the forming properties, of the workpiece in a targeted and, in particular, local manner, without adversely affecting the other requirements placed on the workpiece. In the context of the method, it is particularly possible to realize components made of light metals or light metal alloys with folding radii, which would otherwise be produced only with steel materials.

A method is preferred in which a metal sheet is used as the workpiece. This is first heated at least in a flat edge region and then folded in the heated, flat edge region. Preferably, a total of planar board is used as workpieces. In a preferred embodiment, the heating therefore takes place before a first deformation of the workpiece in a still planar state. This greatly simplifies heating, reduces the time required for heating, and reduces heating costs.

It is also preferred an embodiment of the method, which is characterized in that the workpiece comprises a light metal or a light metal alloy, wherein it preferably consists of a light metal or a light metal alloy. Preferably, the workpiece comprises aluminum or an aluminum alloy or consists of aluminum or an aluminum alloy. Particularly preferably, a workpiece is used which has an aluminum alloy of the 6xxx series or consists of an aluminum alloy of the 6xxx series. In the case of the materials mentioned here, the advantages of the process are realized in a special way. In particular, it is possible to realize using the method even with these materials components with folding radii, which would otherwise be produced only with steel materials, at the same time the heating takes place in a particularly simple and cost-effective manner.

It is also preferred an embodiment of the method, which is characterized in that the workpiece is heated to a temperature of at least 100 ° C to at most 350 ° C. Preferably, the workpiece is heated to a temperature of at least 250 ° C to at most 350 ° C. This temperature range is particularly preferred when increased demands are placed on the bending and / or folding properties of the workpiece, because in this temperature range optimum improvement of the corresponding properties occurs. An embodiment of the method in which the workpiece is heated to a temperature of at least 100 ° C to at most 250 ° C is also preferred. This temperature range is preferably selected if no increased demands are placed on the folding and / or abutting properties of the workpiece. In the lower temperature range, lower costs associated with heating arise, and this can be done faster. Therefore, heating to a temperature in the lower region is favorable if the abutting and / or folding properties of the workpiece realized there are sufficient for its further use.

Particularly preferred is an embodiment of the method in which a board is used as the workpiece, which consists of a series 6xxx aluminum alloy. This realizes in a special way, the advantages of the process.

It is also preferred an embodiment of the method, which is characterized in that the workpiece is heated as a whole. Alternatively, it is possible that only at least one planar edge region is locally heated. Heating the workpiece as a whole is easy and inexpensive to do and generally improves the forming properties of the workpiece. A local heating of the workpiece in at least one flat edge region is particularly fast and efficient feasible.

An embodiment of the method is preferred, which is characterized in that the workpiece is formed after, before or during the heating to a component and bent after forming in the at least one flat edge region. The transformation can take place in one or more stages. So it is an embodiment possible in which the workpiece is formed after heating to a component and then folded. Alternatively or additionally, it is possible that the workpiece is formed into a component prior to heating and bent after the deformation and the subsequent heating. Further, it is alternatively or additionally possible that the workpiece is deformed during the heating, wherein it is then folded.

It is thus possible for the heating to take place selectively on the flat workpiece before a first forming, in particular before a first cold forming stage. It is also possible that the heating is integrated in a forming process, in particular in a cold forming process. A heating of the flat workpiece before forming can be done inline, online or offline, in particular depending on a given infrastructure.

An embodiment of the method is also preferred, which is characterized in that the at least one flat edge region of the component is locally heated prior to folding. This heating can take place before, after and / or during a deformation of the workpiece.

Particularly preferred is an embodiment of the method in which the workpiece is first heated as a whole and then formed into a component. After forming, at least one planar edge region of the component is locally heated, wherein the workpiece is subsequently bent in the heated, flat edge region. In this case, preferably at least one flat edge region is selected for the heating and bending, in which it is subsequently folded.

An embodiment of the method is also preferred in which the workpiece is first heated locally in at least one flat edge region and then converted into a component. Thereafter, the at least one edge region and / or at least one other flat edge region - if necessary again - locally heated, wherein the workpiece is then folded in the at least one heated, flat edge region.

An embodiment of the method is also particularly preferred, in which the workpiece is first heated as a whole or locally in at least one planar edge region and then converted into a component. Then - without reheating - the still warm from the first warm flat edge area is folded. This is possible if the temperature is maintained after the first heating of the workpiece and the bending process follows quickly on the deformation, so that the workpiece is still warm when edging in the flat edge region.

It is also preferred an embodiment of the method in which the workpiece is not heated prior to forming, but rather without prior heating to a Component is formed. Preferably, a cold forming is realized. This embodiment of the method is especially for sheet metal components in question, which require a low degree of deformation for their formation. After the forming, the component is heated locally or locally in at least one flat edge region, wherein it is subsequently bent in the heated, flat edge region.

It is also preferred an embodiment of the method, which is characterized in that the heating is carried out by infrared radiation, inductive, or by direct contact. Heating by direct contact is preferably carried out by means of heated plates. It turns out that the type of heating due to the simple geometry, namely the flatness of the edge region to be heated, can be chosen almost freely. The specific types of heating mentioned are preferred because they are quick, easy, efficient and inexpensive to carry out.

Finally, an embodiment of the method is preferred, which is characterized in that the workpiece is folded in the folded region following the folding. As a result, it is ultimately possible to emphasize optimal folding properties of the workpiece by means of the method and, in particular, to realize folding radii even with light metal materials which would otherwise only be producible with steel materials.

The invention will be explained in more detail below with reference to the drawing. Showing:

1 a schematic representation of a first embodiment of the method;

2 a schematic representation of a second embodiment of the method, and

3 a schematic representation of a third embodiment of the method.

1 shows a schematic representation of a first embodiment of the method in the form of a flow chart. In this case, in a step S1, a workpiece is heated as a whole. Alternatively, however, it is possible for the workpiece to be heated locally in at least one flat edge region in step S1.

In a step S2, the workpiece is formed into a component. The forming can take place in one or more stages.

In a step S3, which follows the deformation in step S2, at least one flat edge region of the workpiece, in which it is to be folded later, is locally heated. Alternatively, however, it is also possible for the deformed component to be heated globally in step S3, wherein of course the at least one flat edge region is also heated.

Subsequent to step S3, the workpiece is folded in a step S4 in the heated, flat edge region - in the heated state.

2 shows a schematic representation of a second embodiment of the method in the form of a flow chart. The steps S1, S2 and S4 are carried out as in the first embodiment, although the step S3 is omitted. Thus, there is no additional heating of the component after forming, in particular no special heating flat edge regions. Rather, at least one flat edge region is bent in the heated state in the step S4, because the temperature after the first heating is still held in the step S1, wherein the bending operation in the step S4 quickly follows the deformation in the step S2. In this case, no additional heating is required after forming.

3 shows a schematic representation of a third embodiment of the method in the form of a flow chart. In this case, the steps S2, S3 and S4 are carried out as in the first embodiment, but the step of the first heating, namely the step S1 is omitted. Instead, the workpiece is directly transformed without prior heating in the step S2, which then followed by this deformation preferably local heating of at least one flat edge region in step S3. It is alternatively possible that in step S3, instead of local heating, global heating of the formed component as a whole takes place. In step S4, the workpiece is in turn bent in the at least one, heated flat edge region - in the heated state -. This third embodiment is particularly suitable for sheet metal components that require a low degree of deformation for their formation. Nevertheless, the advantages of the method are also realized here because the workpiece is folded on the one hand in the heated state and on the other in not folded state, namely heated in at least one flat edge region, so that there is a simple heating with simple geometry of the area to be heated ,

It is necessary in any embodiment of the method to run a complex, complex, three-dimensional geometry to effect the heating. This can thus be carried out on relatively simple, flat contours, so that they can be carried out in particular quickly.

Overall, it is found that the method is simple, robust and inexpensive to carry out, whereby the application of robust heating technologies such as direct contact, induction or infrared radiation is possible. The result is a simple heating geometry and a larger tolerance with respect to the heating range. In particular, a quasi-linear heating of complex three-dimensional component contours in the bending zone is avoided, resulting in a very robust process.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009031449 A1 [0004]

Claims (9)

A method of folding a workpiece comprising the steps of: heating at least one planar edge region of a workpiece, and bending the workpiece in the heated planar edge region. A method according to claim 1, characterized in that a metal sheet, preferably a generally planar board, is used as the workpiece. Method according to one of the preceding claims, characterized in that a workpiece is used, which comprises a light metal or a light metal alloy or consists of a light metal or a light metal alloy, wherein the workpiece preferably comprises aluminum or an aluminum alloy or consists of aluminum or an aluminum alloy, wherein the workpiece particularly preferably comprises an aluminum alloy of the series 6xxx or consists of an aluminum alloy of the series 6xxx. Method according to one of the preceding claims, characterized in that the workpiece to a temperature of at least 100 ° C to at most 350 ° C, preferably from at least 250 ° C to at most 350 ° C, or from at least 100 ° C to at most 250 ° C. , is heated. Method according to one of the preceding claims, characterized in that the workpiece is heated as a whole. Method according to one of the preceding claims, characterized in that the workpiece after, before and / or during the heating to a component formed and folded after forming in the at least one flat edge region. Method according to one of the preceding claims, characterized in that the at least one flat edge region of the workpiece is locally heated prior to folding. Method according to one of the preceding claims, characterized in that the heating by infrared radiation, inductively or by direct contact, in particular by means of heated plates takes place. Method according to one of the preceding claims, characterized in that the workpiece is folded after folding in the folded portion.

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