EP2292344A1 - Method and device for reforming sheet metal - Google Patents

Abstract

The method involves positioning pre-formed sheets on a storage surface (2) i.e. controlled lifter, and lowering a downholder on the pre-formed sheets. The pre-formed sheets are brought in contact with an upper surface of edging punches (4, 5) by lowering the sheets with the storage surface and the downholder and/or by increasing the edging punches after heating the sheets to temperature. Edging sliders (6) are moved on a forming area and an edge of the sheets. A post-forming sheet is removed from the storage surface after loosening the downholder of the punches and the sliders. An independent claim is also included for a device for post-forming sheets i.e. conductive sheets, for a motor vehicle.

Description

The invention relates to a method for Nachumformung of sheets, especially magnesium and / or aluminum-containing lightweight sheets for motor vehicles in the region of their edges and an apparatus for performing the method.

Magnesium is an extremely lightweight material, which has so far been rarely used, mainly because of its relatively low elongation at break in the automotive industry. By heating the board or the drawing part, however, the forming properties can be significantly improved.

From the DE 101 28 199 A1 For this purpose, a device for forming metal sheets, in particular magnesium sheets is known, wherein the metal sheet in the forming space between the upper and lower tool should be at least partially heated. For this purpose, hot air is passed through provided in the upper tool and / or lower tool flow channels in the forming space. Proposed is also an indirect heating, wherein the heat transfer via the press tool, ie upper tool and / or lower tool, which in turn are heated, takes place. The hot forming should be carried out at temperatures between 90 ° and 350 ° C, preferably at a temperature of about 280 ° C.

In the manufacture of larger vehicle components, eg. As in the production of a roof skin made of magnesium, it is often necessary after a first forming process by reshaping to further reshape the edge regions of the sheets. Here, it is important to take into account the relatively high thermal expansion coefficient of magnesium. The dimensions of the component to be reshaped can change considerably depending on the component size during heating to the required forming temperature. For the tool function, there are special features that take into account when designing a postforming equipment for magnesium sheets Need to become. Since the component to be formed does not yet fit in the cold state to the larger Nachformstempel considering the thermal expansion and is also not sufficiently deformable, special measures must be taken for this purpose.

The invention is therefore based on the object to provide a method and apparatus for reshaping of sheets, especially magnesium and / or aluminum-containing lightweight sheets, in which the mentioned problems do not occur.

1. a) ein vorgeformtes Blech auf einer Ablagefläche positioniert,
2. b) ein Niederhalter auf das Blech abgesenkt,
3. c) nach Aufheizen des Bleches auf Umformtemperatur dieses durch Absenken des Bleches gemeinsam mit der Auflagefläche und dem Niederhalter und/oder durch Anheben eines Abkantstempels mit der Oberfläche des Abkantstempels in Berührung gebracht,
4. d) zur Nachumformung ein Abkantschieber auf die umzuformenden Bereiche und den Rand des Bleches zubewegt und
5. e) nach Lösen des Niederhalters, des Abkantstempels und des Abkantschiebers das nachumgeformte Blech von der Ablagefläche entnommen wird.

To solve this problem, a method is proposed, wherein

1. a) positioned a preformed sheet on a shelf,
2. b) lowered a hold-down on the sheet,
3. c) after heating the sheet to forming temperature of this brought by lowering the sheet together with the support surface and the blank holder and / or by raising a Abkantstempels with the surface of the Abkantstempels,
4. d) for Nachumformung a Abkantschieber moved to the reshaped areas and the edge of the sheet and
5. e) after loosening the hold-down, the press brake and the press brake, the reshaped sheet is removed from the shelf.

According to the invention, the sheet is heated before the Nachumformung, ideally in the tool, preferably at least one of the tools, ie the tray surface, the hold and the Abkantstempel directly and / or indirectly heated and only after reaching the required forming temperature of the Abkantstempel with the reshaped edge region of the Connected sheet so that then the actual Abkantschieber can form the edge area around the outer contour present on the Abkantstempel.

Fig. 1

in der Draufsicht und schematisch, abgesehen vom Niederhalter 3 die Umformwerkzeuge, Abkantstempel 4 und 5 und Abkantschieber 6,

Fig. 2

einen Schnitt nach der Linie A-A zu Fig. 1,

Fig. 3

einen Schnitt nach der Linie B-B von Fig. 1 in der Phase des Aufheizens,

Fig. 4

einen Schnitt nach der Linie B-B von Fig. 1 in der Phase des Absenkens und Schließens der Werkzeuge,

Fig. 5

einen Schnitt nach der Linie B-B von Fig. 1 in der Phase des Nachformens und

Fig. 6

einen Schnitt nach der Linie B-B von Fig. 1 in der Phase der Entnahme des nachgeformten Bauteiles.

The invention will be apparent from the attached Fig. 1 - 6 for example, explained in more detail. Show it

Fig. 1

in the plan view and schematically, apart from the hold-down 3, the forming tools, press brake 4 and 5 and Abkantschieber 6,

Fig. 2

a cut to the line AA too Fig. 1 .

Fig. 3

a section along the line BB of Fig. 1 in the heating phase,

Fig. 4

a section along the line BB of Fig. 1 in the phase of lowering and closing the tools,

Fig. 5

a section along the line BB of Fig. 1 in the phase of reshaping and

Fig. 6

a section along the line BB of Fig. 1 in the phase of removal of the reshaped component.

In the figures, the structure of a resource for reshaping a peripheral flange is shown with undercut for a sheet 1 made of magnesium. The operating means has a heatable, designed as a controllable lifting element storage surface 2 for the sheet 1, wherein the nachformende sheet 1 is brought in a raised position over as large a storage surface 2 to the appropriate forming temperature. Since the temperature is applied best from both sides and in the clamped state, a likewise heatable, preferably full-surface resting hold-down 3 is provided as an abutment. After the heating phase, the sheet 1 is freely deposited on the, after heat expansion suitable, preferably also heated Abkantstempel 4, 5. In Fig. 2 this is a rigid punch 4, while in the Fig. 3 - 6 a in the horizontal direction (see double arrow P4) displaceable Abkantstempel 5, which is also referred to as a filling slide, is shown. These also heated filling slide are used in particular for forming undercuts, which are formed by the present at the upper left end of the filling slide projection. After positioning of the Abkantstempels 4 or 5 takes place with closed downholder 3, the actual Nachformvorgang by moving the Abkantschiebers 6 in the direction of the double arrow P3. To remove the finished sheet 1, the Abkantschieber 6 are moved back to their original position and the storage surface 2 are moved in the direction of the double arrow P1 upwards, whereby the spring-loaded hold-down 3 is moved against the spring 8 in the direction of the double arrow P2 upwards and at the end so far away is that the sheet can be removed (see. Fig. 6 ). The shelf 2 is controlled by means of the spring 7 or a similar device in the direction of the double arrow P1 moves.

In the Fig. 2 and 3 is additionally shown in dashed line the position of the reshaped area 9b of the sheet 1, if it is not heated. As a result of the heating of the metal sheet 1, the region to be reshaped assumes the position 9a in the hot state, so that the press-on dies 4 and 5 can then be brought exactly into the reshaping position. In the Fig. 2-6 In addition, the outer edge of the sheet 1 is designated 10, while the non-resting on the support surface 2 of the sheet part 1 forms the outer region 11.

The special feature of the proposal according to the invention is that only after heating the sheet 1 to forming temperature and thus only after reaching the final extent of the rigid Abkantstempel 4 or formed as a filling slide Abkantstempel 5 is brought into the exact position.

LIST OF REFERENCE NUMBERS

1

sheet

2

Shelf for 1 (controlled, heated lift)

3

Downholder (sprung and heated)

4

Punching punch (rigid, heated)

5

Abkantstempel (Füllschieber, heated)

6

folding slide

7

feather

8th

feather

9a

area to be reshaped of 3 (heated up)

9b

Range of 3 (cold) to be reshaped

9c

Range of 3 to be reshaped (after reshaping)

10

Edge of 3

11

outer range of 3 (not resting on 2)

P1

Double arrow (direction of movement of 2)

P2

Double arrow (direction of movement of 3)

P3

Double arrow (direction of movement of 6)

P4

Double arrow (direction of movement of 5)

Claims (8)

Process for the post - forming of sheets (1), in particular magnesium and / or aluminum - containing lightweight sheets for motor vehicles in the region of their edges, wherein a) a preformed sheet (1) on a support surface (2) positioned, b) lowered a holding-down device (3) onto the metal sheet (1), c) after heating the sheet (1) to forming temperature of this by lowering the sheet (1) together with the support surface (2) and the hold-down (3) and / or by raising a Abkantstempels (4, 5) with the surface of the Abkantstempels ( 4, 5), d) for Nachumformung a Abkantschieber (6) on the reshaped areas (9 a) and the edge (10) of the sheet (1) and moved e) after removing the hold-down (3), the Abkantstempels (4, 5) and the Abkantschiebers (6) the reshaped sheet (1) is removed from the support surface (2). A method according to claim 1, characterized in that for heating the sheet (1) to forming temperature one or more of the forming tools shelf surface (2), hold-down (3), Abkantstempel (4, 5) are directly or indirectly heated. A method according to claim 1 or 2, characterized in that the sheet (1) already heated on the support surface (2) is placed. Apparatus for post-forming sheets (1), in particular magnesium and / or aluminum-containing lightweight sheets for motor vehicles in the region of their edges for carrying out the method according to the preceding claims with a support surface (2) for the sheets (1), a hold-down device (3), Abkantstempel (4, 5) and a Abkantschieber (6) for Nachumformung the sheet (1) in the edge region, characterized in that at least one of the tools shelf surface (2), hold-down (3) and Abkantstempel (4, 5) directly and / or are indirectly heated. Apparatus according to claim 4, characterized in that the support surface (2) is designed as a controlled lift. Apparatus according to claim 4 or 5, characterized in that the holding-down device (3) is formed sprung. Apparatus according to claim 4, characterized in that the Abkantstempel (4, 5) is vertically and / or horizontally movable. Apparatus according to claim 4, characterized in that the Abkantschieber (6) from the outside against the reshaped areas (9a, 10) of the sheet (1) is movable.

Images