EP2465621A1 - Electromagnetic forming and/or cutting with adhered push plate - Google Patents

Abstract

The method involves attaching a driving sheet (B) on shaping/cutting region of a sheet material (M). A coil (30) which applies magnetic compressive force on shaping/cutting region is provided on the driving sheet, so as to shape/cut the sheet material. The driving sheet is made of material selected from the group consisting of aluminum, copper, silver, electrical conductive plastic and plastic composite. The sheet material is made of carbon- fiber reinforced plastic material. Independent claims are included for the following: (1) sheet material; and (2) mobile device.

Description

The invention relates to a method for electromagnetic forming and / or cutting a poorly electrically conductive or electrically non-conductive sheet material using at least one drive plate.

In the following text, a flat material is to be understood as meaning a sheet-like material which is dimensionally stable at room temperature and whose thickness is low with respect to the areal extent. It is preferably provided that such a flat material is present in the form of a component or molded part or semifinished product. Under a poorly electrically conductive flat material is to be understood in the following priority that the specific conductivity of the material is significantly worse than that of copper.

In the US 3,365,522 A For example, a method and a corresponding device for the electromagnetic deformation of a plastic sheet material are described. For this purpose, the flat material to be formed is positioned between a coil and a shaping die and subsequently deformed into the die by means of magnetic pressure force. In order to build up the magnetic compressive force, a so-called blowing plate is arranged between the to be formed flat material and the coil. Upon activation of the coil, a current is induced in the electrically conductive blowing plate, to which the magnetic field of the coil exerts a repulsive pressure force. The kinetic energy occurring here in the blowing plate is transmitted by direct contact with the flat material to be formed. By providing cutting edges or the like in the die, cutting of the sheet can also be accomplished.

According to the prior art, the blowing plate is clamped to the reshaped sheet, such. B. in the DE 10 2005 013 539 A1 and DE 10 2005 013 540 A1 shown. This is complex and often leads to unsatisfactory results.

An object of the invention is to show ways in which the disadvantages associated with the prior art can be avoided or at least reduced.

This object is achieved both by a method having the features of claim 1 and by a method having the features of the first independent claim. Preferred developments and refinements are specified in the dependent claims. The features of the dependent claims and the following explanations apply analogously to both methods.

According to further independent claims, the solution of the problem also extends to a specially designed flat material and to a device for performing a forming and / or cutting process, which is in particular a forming and / or cutting device.

The solution of the above object succeeds, on the one hand, in that the blowing sheet is glued or glued onto the sheet material to be formed and / or cut at least locally in the forming and / or cutting area.

The sticking of the blowing plate takes place before the cutting and / or forming process. Preferably, a surface bonding is provided, wherein the forming and / or cutting area can be formed flat or with a spatial shape. Likewise, a line-shaped or selective adhesive application can be provided. A cut line may have an open or a closed course. Furthermore, a cutting line may have a planar or a spatial or three-dimensional course. The blowing plate is also formed from a flat material, which need not necessarily be a metal sheet, as explained in more detail below. The sticking of the drive plate is not precluded that this can be additionally clamped in a conventional manner.

By sticking or gluing the drive plate eliminates the previously required and sometimes very expensive positioning and clamping the drive plate in the appropriate devices. Even the previously required separate replacement of the drive plate deleted. Thus, the entire forming and / or Cutting process easier to handle and faster. In addition, the construction of the corresponding devices (tools) can be simplified. Another advantage is also to be seen in the fact that almost consistently better forming and / or cutting results are achieved because it is ensured that the blowing plate is always in optimal contact with the to be formed and / or flat material to be cut, which incidentally also leads to a better energy efficiency. This is not an exhaustive list.

It is preferably provided that the adhesive to be stuck plate is formed self-adhesive. This is to be understood that the blowing plate is provided at least on one side with an adhesive layer, which adheres to the sheet z. B. is protected by a protective film or the like, which must then be removed on site and before bonding. The adhesive layer may be formed as a surface applied adhesive film. Likewise, the adhesive layer may be in the form of adhesive film strips or adhesive film webs, adhesive film dots or the like. Instead of such an adhesive film, adhesive dots or the like may also be provided. It can likewise be provided that the flat material to be reshaped and / or cut is already provided with an adhesive layer according to the preceding explanations, at least in the forming and / or cutting region.

Particularly preferably, it is provided that the sticking plate to be stuck is provided as a prefabricated adhesive pad. A prefabricated adhesive pad is understood to be a piece of sheet metal or the like adapted in the contour (contour) and / or shaping to the forming and / or cutting region. This makes it possible to provide an optimized for the pressure force training blowing plate. The adhesive pad is preferably provided on one side with an adhesive layer, as explained above. Such adhesive pads may be provided as series parts or made individually as needed, especially on site. Since the driving plates are wear parts, the amount of waste can be reduced by using suitable prefabricated driving plates.

In particular, it is provided that such an adhesive pad is formed with respect to the contour of the forming and / or cutting region, which is essentially predetermined by the die, with a smaller and, preferably, only slightly smaller contour is, wherein this blowing plate is then glued within the actual forming and / or cutting area on the to be formed and / or to be cut flat material. In this case, the blowing plate can mitgeformt or pressed together with the sheet through a cutting die, as explained in more detail below in connection with the figures.

Furthermore, it can be provided that the adhesive pad is formed larger than the forming and / or cutting area and thus z. B. can be additionally clamped on its outer edge. In this case, several scenarios are possible for the forming and / or cutting process. In a first scenario, the glued blowing sheet is formed and / or separated together with the flat material to be formed and / or cut. In a second scenario, the glued-on blowing plate is detached from the flat material during forming and / or cutting, as explained in more detail below in connection with the figures.

It is preferably provided that the thickness of the blowing plate is less than or equal to 1 mm, preferably less than or equal to 0.8 mm, in particular less than or equal to 0.5 mm and particularly preferably less than or equal to 0.3 mm. A blowing plate with a thickness of less than or equal to 0.5 mm can also be referred to as a blowing film. Especially in the custom-made and especially manual one-off production of prefabricated adhesive pads, the use of propellant films proves to be particularly advantageous.

As a material for the blowing plate or for the blowing film are preferably aluminum and aluminum alloys, copper and copper alloys, and silver-containing alloy into consideration.

Alternatively, as the material for the blowing plate, an electrically conductive plastic or a plastic composite can be used. The electrical conductivity of a plastic or a plastic composite can, for. B. be improved by integrated metal foils, metal wires or metal baubles. A further idea here is that such a blowing plate provided as a pre-assembled, ie in contour and shape adapted to the forming and / or cutting area injection molded part is, wherein it is in such an injection molded part z. B. may be a plastic over-molded metal foil.

The flat material to be reshaped and / or cut can be a metal sheet, in particular a steel sheet, a laminate sheet, in particular a sandwich sheet containing plastic, or an organic sheet. Furthermore, the flat material to be formed and / or cut can also be a plastic material or a plastic-containing material. These materials are preferably in the form of semi-finished products (for example plates, profiles and the like) or spatially shaped components. To transform these materials, a separate heat input may be required.

It is preferably provided that a flat material to be formed and in particular to be cut is a plastic material, preferably a fiber-reinforced plastic material and in particular a CFRP material. Fiber-reinforced plastic materials are understood to be dimensionally stable and, in particular, also cured composite materials which consist of a plastic matrix and reinforcing fibers embedded therein, in particular carbon fibers. These materials are preferably in the form of semi-finished products (for example plates, profiles and the like) or spatially shaped components.

Above all, the cutting of fiber-reinforced plastic materials by the method according to the invention represents a very interesting aspect, since conventional devices for mechanical cutting of these materials, due to the fiber content contained therein, are subject to very high wear. With the method according to the invention, a reliable cutting of semi-finished products and components made of a fiber-reinforced plastic material is made possible, wherein in particular the very stable carbon fibers of a carbon fiber reinforced plastic material (CFRP) are reliably separated at the cutting edge. Since in the method according to the invention the cutting takes place without relative movements between tool parts, only a relatively small amount of wear occurs on the cutting edge or edges, whereby the operating costs are relatively low. Further advantages include good reproducibility of the cutting results and short processing times. With the method according to the invention Furthermore, cuts in difficult to access component areas are possible, which are not accessible for mechanical cutting elements or for a cutting laser beam.

The cutting of fiber-reinforced plastic materials can also be carried out with only clamped driving plates and offers significant advantages over the conventional mechanical cutting of these materials.

On the other hand, however, the solution of the above object is also achieved by the fact that the blowing plate is incorporated or embedded at least locally and preferably only locally in the forming and / or cutting area in the flat material to be reshaped and / or cut.

The flat material to be formed and / or cut is provided, as it were, with at least one already integrated blowing plate for the cutting and / or forming process, wherein the at least one blowing plate is arranged in an area to be subsequently formed and / or cut. A driving plate is z. B. so incorporated into the reshaped and / or to be cut flat material, that this forms part of the surface in the forming and / or cutting area or at least positioned near the surface. It is preferably provided that such a blowing plate is a blowing film (i.e., the film thickness is 0.5 mm or less). Instead of a sheet or a foil and wires or wire mesh could be incorporated into the sheet. Separate protection is claimed for such a flat material. Further developments are analogous to the preceding and following explanations.

In a CFRP flat material, the integration of a drive plate (possibly also of wires or wire mesh) z. B. be achieved in that in the curing tool at the appropriate location or at the appropriate places a metal foil is inserted, which is then embedded as close to the surface as possible in the composite material.

Again, different scenarios are possible for reshaping and / or cutting. In a first scenario, the incorporated blowing plate remains after forming and / or cutting in the flat material. In a second scenario will the blowing plate during forming and / or cutting, or afterwards, dissolved out of the composite material. In a third scenario, the blowing plate remains in a waste part and can be disposed of with it.

The inventive method can be carried out with a mobile or a stationary device, wherein for such, in particular mobile device, separate protection is claimed. Further developments are analogous to the preceding and following explanations.

A mobile device may e.g. B. be executed as a pincer-like device, wherein the die and the coil, in particular interchangeable, are arranged on opposite legs and in this way on a semifinished product or on a component from the outer edge forth to a forming and / or interface (or to a Forming and / or cutting area) can be performed. At the forming and / or interface, a blowing plate or a pre-assembled adhesive pad has to be glued to the flat material beforehand. Such a device allows a very flexible introduction of holes in the sheet and / or performing local transformations. The two-sided application of the die and coil to be reshaped and / or to be cut flat material, as well as the application of clamping forces, z. B. be accomplished with hydraulic, pneumatic and / or electromechanical actuating means. Such a mobile device may e.g. B. be attached to a robot arm, a 3D guide or the like and hereby moved or guided. Likewise, such a mobile device could be designed as a handheld device, which then ideally load compensation means are provided in order to handle this device can.

A stationary device is z. B. a locking device in which the die z. B. at a table and the coil are arranged on a relatively movable plunger. Again, it is preferably provided that the die and the coil are interchangeable received in this device. Also, magazines, such as Revolvermagazine, with different matrices and coils conceivable to allow a quick change and to achieve high flexibility.

Fig. 1

zeigt in zwei Teilbildern das Schneiden eines Flachmaterials, vor dem Schneidvorgang (Fig. 1 a) und unmittelbar nach dem Schneidvorgang (Fig.1b).

Fig. 2

zeigt eine erste Abwandlung.

Fig. 3

zeigt eine zweite Abwandlung.

Fig. 4

zeigt in drei Teilbildern das Einbringen eines Lochs in ein Bauteil.

Fig. 5

zeigt in zwei Teilbildern das Umformen eines Flachmaterials, vor dem Umformvorgang (Fig. 5a) und unmittelbar nach dem Umformvorgang (Fig. 5b).

Fig. 6

zeigt ein Flachmaterial mit integriertem Treibblech.

The invention and the inventive principle will be explained in more detail by way of example with reference to the figures.

Fig. 1

shows in two partial images the cutting of a flat material, before the cutting process ( Fig. 1 a) and immediately after the cutting process ( 1b shows ).

Fig. 2

shows a first modification.

Fig. 3

shows a second modification.

Fig. 4

shows in three fields the introduction of a hole in a component.

Fig. 5

shows the forming of a flat material in two partial images, before the forming process ( Fig. 5a ) and immediately after the forming process ( Fig. 5b ).

Fig. 6

shows a flat material with integrated blowing plate.

In the figures, identical or functionally identical components are designated by the same reference numerals. Incidentally, it should be noted that in the context of the invention, the features of the examples explained below can be combined as desired, provided that there is no technical contradiction.

Fig. 1a shows a schematic sectional view of a total of 100 designated device. The device has a die 10 with a circumferential cutting edge 11, wherein the cutting edge 11 is formed at the upper end of a downwardly enlarging opening 12. In the example shown, the die 10 is formed integrally with a subframe 20. However, it can also be provided that the die 10 is formed as a separate tool part and fixed to the sub-frame 20, which is indicated by the two dashed lines 14. Instead of the illustrated cutting edge 11, a cutting blade or the like may be provided.

The device 100 further comprises a coil 30, which is integrated in an actuator 40. The coil 30 is positioned opposite the die 10 and with respect to aligned with the cutting edge 11. In the example shown, the coil 30 is designed as a flat coil. The electrical connection lines to the coil 30 are not shown. The actuator 40 with the coil 30 is held in a top frame 50.

Between the sub-frame 20 and the upper frame 50, a plate-shaped flat material M to be cut is clamped. In the area between the die 10 and the coil 30, a so-called blowing plate B is glued to the flat material M on the coil side. In the example shown, a recess 51 is formed in the frame 50 on the contact side to the flat material M in order to make room for the blowing plate B.

Upon electrical activation of the coil 30, which z. B. can be done by capacitor discharge, a current is induced in the blowing plate B, to which the magnetic field of the coil 30 exerts a repulsive pressure force, whereby the blowing plate B is pushed away from the coil 30. The kinetic energy acting in the blowing plate B is transmitted directly (by contact contact) to the flat material M to be cut. As a result, the flat material M is driven into the recess 12 and separated at the cutting edge 11 from the remaining between sub-frame 20 and upper frame 50 flat material M, as in Fig. 1b shown. The same applies to the glued blowing plate B, which is also cut or separated at the cutting edge 11. The separated from the flat material M surface piece is denoted by A, which may be a piece of waste or a cut part (use piece) depending on the purpose. As shown, remains on the surface piece A with severed blowing plate B.

Fig. 2 shows a modification in which, for example, the Fig. 1 (see in particular Fig. 1 b) the blowing plate B not cut, but the separated piece of surface A is replaced by the blowing plate B. Fig. 3 shows a modification in which, for example, the Fig. 1 (see in particular Fig. 1a ) the blowing plate B is cut and positioned (ready-made blowing plate) so that it is located within the peripheral cutting edge 11 and subsequently driven through the cutting die 10 together with the separated surface piece A without being cut by itself.

In the in the FIGS. 1 . 2 and 3 As shown, the section line has a closed, z. B. circular, and level course. In the separated area piece A is therefore z. B. a circular disk. In an analogous manner, it is possible to generate open and / or three-dimensional sectional lines. It is also possible in an analogous manner, in tubes (or the like) arbitrarily shaped cutting lines and in particular to introduce holes, in which case the matrices are formed as cutting mandrels.

In connection with Fig. 4 the introduction of a hole into a component formed from a flat material is explained below. Fig. 4a shows such a total designated P component, which is z. B. may be a deep-drawn or injection-molded component, or even a CFRP component act. The dotted and designated C line indicates a closed and spatially extending cutting line along which a hole or an opening is to be introduced into the component P. The introduction of the hole is analogous to the preceding explanations.

First, a blowing plate B is assembled and glued on the component P, that this is within the section line C (but this need not necessarily be so). this shows Fig. 4 b. If the blowing plate B is to be assembled and applied manually, a self-adhesive metal foil is recommended. Subsequently, the component P is positioned in a cutting device with a correspondingly formed cutting die and a coil arranged correspondingly thereto (alternatively, a mobile device, as explained above, can be used). Subsequently, the cutting operation is performed, wherein along the cutting line C, a surface piece is cut out, on which the blowing plate B remains glued. Fig. 4c shows the component P with hole introduced W. The generated cutting edge is denoted by E.

The Fig. 5a and the Fig. 5b show analogous to Fig. 1 (or to the Fig. 1 a and 1 b) a device 100, the die 10, however, is not formed as a cutting die, but as a molding die. For this purpose, the die 10 has a concave shaping section 13 (see Fig. 5a ), in the activation of the drive coil 30, the flat material M to be formed is driven in together with the driving plate B. Shows the final state of the transformation Fig. 5b ,

By appropriate design of the shaping section 13 also embossments in the flat material M can be generated. The sheet material M formed into a shaped part can be removed after opening the device 100. Depending on the intended use of the molded part produced, if appropriate, the blowing sheet B glued onto the flat material M is to be removed. Likewise, the blowing plate B, for example as a reinforcement, could remain on the molded part.

In an analogous manner to the examples shown in the figures, a combined cutting and forming process is conceivable in which the sheet is both deformed and cut in any sequence.

A modification provides that the blowing plate is not glued directly to the flat material, but that at least one intermediate layer is disposed between the flat material and the blowing plate, which can also be glued or glued. In this case, the effective compressive force by means of the intermediate layer and thus indirectly from the blowing plate B is transferred to the to be formed and / or to be cut flat material M. As a result, z. B. the surface of the reshaped and / or to be cut flat material can be spared.

In order to absorb the forces which occur during electromagnetic forming and / or cutting and in some cases very high forces, the lower frame 10 and the upper frame 50 have large masses. In addition, they are stiff and stable designed to avoid elastic or plastic deformation. Alternatively or additionally, z. B. by a press or locking device, locking forces are applied, which is indicated in the figures by the arrows denoted by F.

Fig. 6 shows a schematic sectional view of a flat material M made of an electrically non-conductive material, wherein it is z. B. may be a CFRP material. In the flat material M, a blowing plate B is incorporated, which forms a part of the turning surface of the coil. Gluing the drift plate, as in the FIGS. 1 to 5 shown, is not required in such an integrated blowing plate. For the rest, reference is made to the above explanations.

LIST OF REFERENCE NUMBERS Electromagnetic forming and / or cutting with glued blowing plate

10

die

11

cutting edge

12

breakthrough

13

forming section

14

Mold parting line

20

subframe

30

Kitchen sink

40

actuator

50

top frame

51

recess

100

contraption

A

Patch (cut piece)

B

blowing plate

C

Cutting line, cutting line course

e

cutting edge

F

Clamping force

M

flat material

W

hole

Claims (10)

Method for electromagnetically forming and / or cutting an electrically poorly conducting or an electrically non-conducting flat material (M) using at least one drive plate (B), which in the forming and / or cutting area generates a magnetic compressive force on a coil (30) transmits and / or cuts flat material (M),
characterized in that
the blowing plate (B) is at least locally glued in the forming and / or cutting area on the to be formed and / or to be cut flat material (M). Method according to claim 1,
characterized in that
the sticking plate (B) to be glued on is self-adhesive. Method according to claim 1 or 2,
characterized in that
the stick-on sheet (B) to be adhered is provided as a prefabricated adhesive pad. Method according to one of the preceding claims,
characterized in that
the thickness of the blowing plate (B) is ≦ 1 mm, preferably ≦ 0.8 mm, in particular ≦ 0.5 mm, and particularly preferably ≦ 0.3 mm. Method according to one of claims 1 to 4,
characterized in that
the blowing plate (B) consists of an aluminum material, a copper material or a silver-containing material. Method according to one of claims 1 to 4,
characterized in that
the blowing plate (B) consists of an electrically conductive plastic or plastic composite. Method according to one of the preceding claims,
characterized in that
the flat material (M) to be formed and primarily to be cut is a plastic material, preferably a fiber-reinforced plastic material and in particular a CFRP material. Method for electromagnetically forming and / or cutting an electrically poorly conducting or an electrically non-conducting flat material (M) using at least one drive plate (B), which in the forming and / or cutting area generates a magnetic compressive force on a coil (30) transmits and / or cuts flat material (M),
characterized in that
the blowing plate (B) is at least locally incorporated in the forming and / or cutting area in the to be formed and / or to be cut flat material (M). Flat material (M), in particular designed as a semi-finished plastic material or fiber-reinforced plastic material which is at least locally in at least one provided for electromagnetic forming and / or cutting area with an incorporated drive plate (B), in particular a metallic propellant film formed. Device (100), in particular a mobile device, for carrying out a forming and / or cutting process on an electrically poorly conducting or an electrically non-conducting flat material (M) according to a method according to one of the preceding claims 1 to 8.

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