EP3778056B1 - Method for thermoforming aluminium sheets by means of stretch forming - Google Patents

Description

The invention relates to a method for the hot forming of aluminum sheets. The device that is used in the method includes a pressing device with a hot-forming stretch-drawing tool, which includes a first tool and a second tool that can be closed in a form-fitting manner with the first tool.

For the hot forming of aluminum sheets, it is known, similarly to steel sheets, to subject the sheets to a deep-drawing process or a stretch-forming process, also called a stretch-forming process. In the stretch drawing process, the sheet metal to be deformed is absolutely held in a surrounding hold-down area, so that this area does not take part in the forming process.

A corresponding method and a device for this purpose is available, for example DE 36 10 022 C2 known to the applicant, with which beads can be made in a sheet. In doing so the metal sheet in the area surrounding a deformation area provided for forming a bead is firmly clamped between a lower tool and an upper tool, pressing surfaces facing one another and each having a recess, and pulled with its deformation area over a beading bar. The metal sheet is inserted between the lower tool provided on a press table and the upper tool provided on a press beam and arranged opposite to this and movable, and the upper tool is non-positively connected to the lower tool.

In contrast to this, deep drawing means that the sheet metal to be formed flows in a controlled manner in the hold-down area and thus takes part in the forming process. In the top view, the blank is larger before the forming process than after the forming process. A deep-drawing process for aluminum sheets using hot forming is, among other things, DE 10 2006 035 239 B3 disclosed by way of example. In this case, a heated molten metal or molten salt is used, the volume of which is previously controlled, in order to bring the metal component to be formed to the right temperature.

Aluminum sheets pose a challenge for hot forming processes because class 5000 aluminum alloys have an A5 elongation at break of around 20% at room temperature. However, due to this limitation, the form-change work that can be performed in the deep-drawing process is relatively limited. When using the stretch-drawing process, the deformation work that can be performed is even more limited, since this essentially occurs in the area of the drawing punch and die radii, i.e. in the edge area of the drawing punch or dies. Under otherwise identical conditions, the failure of the aluminum sheet occurs in the form of so-called tears stretching process considerably earlier than in the deep-drawing process.

If, despite this, significantly greater deformation work has to be carried out on various aluminum alloys, the forming must, depending on the requirements, take place in the sheet metal temperature range of approx. 350 °C (warm forming) to approx. 540 °C (hot forming). In this temperature range, aluminum sheets have a doughy consistency and care must be taken to ensure that the sheet does not crack during the drawing process.

Another limitation is the lack of flexibility in the deep-drawing process, because deep-drawing tools for warm and hot forming are extremely expensive, which is why changes are avoided. If, for example, several indentations are to be made in the aluminum sheet, the dimensions of the tool also determine the distances between the indentations and their dimensions. Changes to the distances or the dimensioning then require expensive new tools.

Out of US 4,792,318A There is known a mask molding device for molding a shadow mask of a color cathode ray tube with a device applying hot pressing. The device comprises a mold for applying pressure to the plate-shaped element, which comprises a heated inner section and an outer section, and insulating means between the inner and outer sections to reduce the heat transfer from the inner section to the outer section and the thermal to increase the efficiency of the device. The mold includes a die having a defined shape, a punch cooperating with the die to form the sheet-like element into the defined shape, a clamp for holding the sheet-like element Elements during the molding process and an ejection to remove the mask from the die. The inner section contains a heated portion of each of the die, punch, clamp and ejector and optionally a heater. Thus, the heat for hot pressing is applied to those portions of the die that come into contact with the plate-shaped member. At the same time, thanks to the heat-insulating element inserted at the division with the other parts, the heat is not conducted over a large area. As a result, there is no seizing of moving parts caused by differences in thermal expansion due to large-area heat conduction, operation can be smooth at all times, and the energy required for heating is reduced.

US 2014/0260493 A1 describes a hot stamping die having both a high strength and a low strength unit for producing shaped goods. Here, a steel sheet is heated to an appropriate temperature to perform forming in a die, and then quenching is performed to produce high-strength parts. A heating mold, which is installed on one side of a cooling mold to form a shaped surface together with the cooling mold, is provided with a cartridge heater or heating cartridge, which is installed on one side of the heater, and may include a plurality of landing blocks placed between the cooling mold and the heating mold are arranged.

In contrast, the present invention is based on the object of creating a method with which it is possible to subject aluminum sheets to hot forming, with high flexibility being ensured even with high deformation work.

This object is achieved by a method for hot-forming aluminum sheets by stretch-drawing in a device for hot-forming aluminum sheets by stretch-drawing, comprising a pressing device with a hot-forming stretch-drawing tool, which has a first tool, in particular a lower tool, and a second tool that can be closed in a form-fitting manner with the first tool, in particular upper tool, wherein the first tool comprises a first base plate with a heatable drawing punch, at least one first heatable hold-down device, at least one first coolable hold-down device and at least one pressure-regulatable first hold-down cylinder, the second tool comprising a second base plate with a heatable die part, at least one heatable Sheet metal counter-holder, at least one second coolable hold-down device and at least one pressure-regulatable second hold-down cylinder, wherein the first base plate or the second base plate is attached to a movable, in particular path- and force-controlled, device of the pressing device, with an edge being held down by means of the first and second tools of an aluminum sheet and stretching over the heatable die part is made possible, with the method being further developed in that the heatable and coolable tool elements are heated or cooled to their respective specified temperatures, after the specified temperatures have been reached, an aluminum sheet to be formed is positioned correctly between the first tool and the second tool is introduced, and the hot-forming tool is closed in a form-fitting manner, wherein when the aluminum sheet has reached its predetermined temperature under the action of the heat of the heated tool elements, the stretching movement of the movable tool is started and carried out to a predetermined drawing depth.

The invention is based on the basic idea that instead of a deep-drawing process, a stretch-drawing process is used in which the aluminum sheet is held in a circumferential hold-down area for each stretch-drawing process, so that the outer part of the aluminum sheet does not take part in the forming. This is available for further forming processes, so that by repeated stretching with the same device and the same tool, a series of similar, but possibly differently spaced depressions can be introduced into the sheet metal.

In the first tool and the second tool, the heatable hold-down elements, i.e. the heatable hold-down device and the heatable sheet metal counter-holder, are each arranged adjacent to the heatable drawing punch or to the heatable die part, with the respective coolable hold-down elements, i.e. the first coolable hold-down device and the second coolable hold-down device, follow. These cause a temperature gradient in the aluminum sheet in the hold-down area, which decreases from the inside to the outside, so that the outer area of the aluminum sheet in the hold-down area has a low temperature, which stabilizes the sheet material in relation to the stretching process and ensures that the outer area is not deformed.

This measure is particularly favorable for using the device for multiple stretching on an aluminum sheet with intermediate displacement of the aluminum sheet from a first to a second position, etc.

In embodiments, there is a non-coolable pressure receiving body in the first tool and a non-coolable one in the second tool Arranged pressure distribution body, which are adapted in particular in cross-section to the dimensions of the drawing punch and the die part.

Pressure-resistant insulation materials are preferably located between the heatable tool elements and the coolable tool elements and/or the non-coolable tool elements. These pressure-resistant insulation materials make it possible to better thermally separate the heatable elements and the coolable elements from one another and thus achieve an improved temperature profile in the aluminum sheet.

In embodiments, the heatable tool elements each have one or more heating cartridges. The heating cartridges can be electrical resistances which, when closed by a current, give off heat in proportion to the intensity of the current. Advantageously, the heatable tool elements each have their own temperature control, in particular with their own data storage. In this way, it is possible to locally heat the aluminum sheet to be formed differently in different areas according to the local needs of the forming work.

In embodiments, one or more of the heatable tool elements and/or one or more of the coolable tool elements have one or more temperature sensors which are arranged, in particular near the surface or in the surface facing the aluminum sheet, such that a temperature of the aluminum sheet is in the region of the respective temperature sensor can be determined. The temperature of the aluminum sheet can also be determined indirectly, for example by measuring the temperature-dependent deformation work during forming as a function the deformation achieved. It is advantageous if the temperature is monitored over the entire area of the aluminum sheet that takes part in the hot forming process.

If there is advantageously a path measuring device on the hot forming stretch-drawing tool, which is designed and set up to measure the movement and speed of the moving first or second tool compared to the non-moving second or first tool in connection with the movable path and force-controlled device of the pressing device and the temperature control of the heatable To regulate tool elements, a very precise and safe process control is guaranteed. During the movement of the movable tool, both the path covered by the drawing punch or the movable tool and the force applied for this are measured and compared with setpoint values in the path and force control. For a reliable forming process, the force should be within a specified range of values depending on the path covered, in order to avoid tearing in the aluminum sheet. As soon as this specified value corridor is left, the process is interrupted in order to bring the material of the aluminum sheet back to the specified temperature, in which case the force used also returns to the specified value corridor. The forming process can therefore be discontinuous.

Advantageously, after a stretch-drawing process, the aluminum sheet is repositioned and a further, similar stretch-drawing process is carried out on a part of the aluminum sheet that has not yet been stretch-drawn. This is made possible by using the stretch drawing process with additional cooling of the aluminum sheet in the outer edge area of the hold-down area. On In this way, depressions of the same type can be made in the aluminum sheet at variable distances from one another using the same device.

Preferably, during a stretching operation, the predetermined temperatures of any or all of the tooling elements and/or the aluminum sheet are monitored and the stretching movement is interrupted if one or more of the temperatures are outside a predetermined acceptable temperature range and resumed when all monitored temperatures are back within their predetermined ones are within acceptable temperature ranges.

In embodiments, different temperature controls are used between the at least one first hold-down device and the at least one sheet metal counterholder and between the drawing punch and the die part in order to compensate for different deformation forces in the areas of the drawing punch radius and sheet metal counterholder radii. The drawing punch radius and the sheet metal counter holder radii are located in the area at the outer edge of the drawing punch or on the inner edges of the sheet metal counter holders, which are arranged towards the drawing punch. During the stretch-drawing process, the aluminum sheet gets between the drawing punch and the sheet metal holder(s) in this area and thus experiences the greatest change in shape. In this area, the drawing punch and the sheet metal counterholder have rounded edges, the so-called radii, on their lateral edges. The curvature of the radii has an influence on the drawing behavior of the aluminum sheet during the stretching process, since different friction conditions occur in the radii, especially in the corner radii. A temperature gradient between the heatable hold-down elements and the central heatable elements, i.e. drawing punches and die part, can therefore ensure the safe forming of the aluminum sheet in this area.

The temperature controls of the heatable tool elements are preferably adjusted overall and among one another during a stretching process due to changing deformation work. In embodiments, the heatable tool elements can be heated to a predetermined temperature between 515°C and 540°C. These temperatures are particularly favorable for class 5000 aluminum sheets. Other temperature ranges may be more favorable for other aluminum sheets.

A pressure is advantageously set in the at least one first hold-down cylinder which ensures that the aluminum sheet is held in place during the stretching process and/or a pressure is set in the at least one second hold-down cylinder which ensures that the aluminum sheet continues to flow during the stretching process.

The temperatures and pressures to be used for the stretching process according to the invention depend on the material used and can be determined in tests.

Further features of the invention will be apparent from the description of embodiments of the invention taken together with the claims and the accompanying drawings.

Within the scope of the invention, features that are marked with "particularly" or "preferably" are optional features to understand.

Fig. 1

eine perspektivische Darstellung eines in einem Tiefziehverfahren hergestellten Aluminiumblech-Formkörpers,

Fig. 2

eine perspektivische Darstellung eines in einem erfindungsgemäßen Reckziehverfahren hergestellten Aluminiumblech-Formkörpers und

Fig. 3

eine schematische Darstellung einer Vorrichtung zur Warmumformung von Aluminiumblechen.

The invention is described below without restricting the general inventive concept using exemplary embodiments with reference to the drawings, with express reference being made to the drawings with regard to all details according to the invention that are not explained in more detail in the text. Show it:

1

a perspective view of an aluminum sheet molding produced in a deep-drawing process,

2

a perspective view of an aluminum sheet molding produced in a stretch-drawing process according to the invention and

3

a schematic representation of a device for the hot forming of aluminum sheets.

In the drawings, elements and/or parts that are the same or of the same type are provided with the same reference numbers, so that they are not presented again in each case.

1 shows a perspective view of a shaped aluminum sheet body 20 produced in a deep-drawing process. The deep-drawing tool, not shown, has a complicated geometry with several relief parts, which ensure the depressions 21 in the shaped aluminum sheet body 20, which extend towards the ends of side areas 22 of fixed width and are spaced from each other with webs 24 fixed width. The opening areas 23 of the depressions 21 each have a fixed width that is dependent on the width of the respective drawing punch. The aluminum sheet molding 20 is based on an aluminum sheet from an aluminum quality Group 5000 and can be produced in the deep-drawing process in the temperature range of approx. 350 °C. Following the deep-drawing process, cutting to the final dimensions is carried out using a laser or other cutting options, and the openings are created in the area of the depressions 21.

The dimensions and spacing of the depressions 21 cannot be changed with the selected deep-drawing tool. The economic limit is exceeded if, for example, the center-to-center distance of the large-area depressions 21 is changed under otherwise identical conditions.

In contrast, shows 2 a perspective view of an aluminum sheet shaped body 20 produced in a stretch-drawing process according to the invention. For this purpose, the stretch-drawing process is carried out several times in succession on the aluminum sheet, with the aluminum sheet being displaced in the device in each case in order to produce the next indentation 21 in each case. If the dimensions of the depressions 21 are otherwise the same, they are therefore at different distances from each other, which can be seen from the different dimensions of the webs 25 and 26 with variable widths in the lower area of the figure. These center-to-center distances can be set differently from mold to mold because they only depend on the positioning of the aluminum sheet on the device. The width of the side areas 22 can also be flexibly adjusted.

3 shows a schematic representation of a device for the hot forming of aluminum sheets 14. The device comprises a pressing device with a hot forming stretch-drawing tool, which has a first and a second tool. in the in 3 shown representation is that first tool below the aluminum sheet 14 and the second tool above the aluminum sheet 14, so that one speaks of a lower tool and an upper tool. However, the invention is not limited to this configuration, since the arrangement of the first and second dies can be reversed and the orientation of the aluminum sheet 14 need not be horizontal.

The first tool, in this case the lower tool, rests on a first base plate 1 on which the other tool elements of the first tool are arranged. At its core is a heatable drawing die 2 which is supported on the first base plate 1 via a pressure-resistant insulating material 13 and a pressure-receiving body 11 which cannot be cooled. The drawing punch 2, over which the aluminum sheet 14 is drawn in the stretch-drawing process, has a drawing punch radius 15 on its peripheral edge pointing towards the aluminum sheet 14, which ensures a transition between the central drawn part of the aluminum sheet 14 and the outer edge of the aluminum sheet 14 during stretching , which does not participate in the transformation.

On the outside, the drawing punch 2 is surrounded by a likewise heatable, first heatable hold-down device 3 , which in turn is surrounded on the outside by a pressure-resistant insulating material 13 and a first, coolable hold-down device 4 . These three tool elements, in cooperation with corresponding tool elements of the second tool, serve to clamp a hold-down area of the aluminum sheet 14 in such a way that it is held during stretching so that the aluminum sheet 14, unlike in deep drawing, does not flow. The first heatable hold-down device 3, the pressure-resistant insulating material 13 and the first coolable hold-down device 4 are held down by first hold-down cylinders 5 is subjected to a pressure which ensures that the hold-down area of the aluminum sheet 14 is held in place.

The second tool, in the case of the 3 the upper tool comprises a second base plate 6 which is arranged parallel to the first base plate 1 . A heatable matrix part 9 is supported centrally on the second base plate 6 via a correspondingly dimensioned, pressure-resistant insulating material 13, a likewise correspondingly dimensioned, non-coolable pressure distribution body 12 and second hold-down cylinders 8. The die part 9 has the same dimensions as the drawing punch 2 in cross section and is arranged flush with the drawing punch 2 . The second hold-down cylinders 8 ensure a pressure that is exerted by the die part 9 via the aluminum sheet 14 on the drawing punch 2, which ensures that the aluminum sheet 14 can continue to flow in this area during the hot forming process.

A heatable sheet metal counter-holder 7 connects outwards to the central die part 9 , which is opposite the first heatable hold-down device and is supported on the second base plate 6 via its own pressure-resistant insulating material 13 and a pressure-release body 18 . A pressure-resistant insulating material 13 and a second coolable hold-down device 10 are connected to the outside, which is supported on the second base plate 6 in the exemplary embodiment shown.

The pressure-resistant insulation materials 13 arranged between the heatable tool elements 2, 3, 7 and 9 and the coolable tool elements 4 and 10 and the non-coolable tool elements 11 and 12 serve for thermal decoupling.

The representation in 3 is schematized and does not form concrete ones dimensions. In particular, the tool elements of the hold-down area can be made significantly narrower in relation to the drawing punch 2 than shown. The configuration shown, in which tool elements located opposite one another are aligned with one another in the direction of movement, is advantageous for a controlled setting of temperature gradients in the aluminum sheet 14, but is not essential. It is more important that, as is usual with stretching and deep-drawing tools, the inner edges of the first heatable hold-down device 3 and the heatable sheet metal counter-holder 7 on the one hand and the outer edges of the drawing punch 2 and the die part 9 on the other hand are aligned with one another and leave a space open for the aluminum sheet 14. The dimensioning of the insulating materials, which are optionally inserted between the heatable and the coolable or non-heatable or coolable tool elements, can also be suitably selected. Also the fact that in the representation in 3 aligning the various tool parts with their edges in the horizontal is advantageous but not essential.

The first and second hold-down cylinders 5, 8 primarily serve to generate the pressure with which the aluminum sheet 14 is held in the central area on the one hand and in the hold-down area on the other hand between the upper tool and the lower tool. The actual stretching process includes a relative movement of the second base plate 6 with respect to the first base plate 1, it being irrelevant for the invention which of the two base plates is moved and which is fixed. The process is explained below using the example that the second tool, in this case the upper tool, is moved and the first tool is fixed.

Each individual heatable tool element listed above has at least one, but preferably several heating cartridges and its own temperature control with appropriate data storage. There is a path measuring device (not shown) on the stretching tool in the pressing device, which regulates the downward movement of the upper tool and the speed of the downward movement in direct connection with the movable path and force-controlled device of the pressing device and the temperature control of the heatable tool elements. The pressure in the hold down cylinder 5 and its system is adjusted to the pressure that ensures the absolute hold of the aluminum sheet 14 in the hold down area during the hot forming process. The pressure in the hold-down cylinder 8 and its system is adjusted to the pressure that ensures the continued flow of the aluminum blank during the hot forming process.

The method according to the invention is carried out as follows. The tool in the pressing device, consisting of the upper tool and the lower tool, is positively closed. The heatable drawing punch 2, the heatable hold-down device 3, the heatable sheet metal counterholder 7 and the heatable die part 9 are heated by means of integrated, electrical heating cartridges to a temperature of, for example, 515 °C to 540 °C, which is suitable for aluminum sheets of the 5000 grade as has proven particularly suitable. Different temperatures may be more suitable for other grades.

As soon as all of the tool components described above have reached the specified temperature, the tool is opened, the aluminum blank 14, which may have been previously coated with a temperature-resistant drawing oil in the deformation area, is placed in the correct position in the tool and the Tool closed positively. So that the aluminum sheet 14 can be heated, the positive connection with the drawing punch 2 and the die part 9 as well as the hold-down device 3 and the sheet metal counter-holder 7 must be ensured.

As soon as it is detected by indirect measurement that the aluminum sheet 14 has also reached the specified temperature, the downward movement of the movable device of the pressing device, in the example the downward movement of the second tool, is triggered. During the downward movement, the actual drawing process, the aluminum sheet 14 is pulled over the drawing die 2 until the specified drawing depth is reached. In the holding area, the force must be regulated in such a way that the aluminum sheet 14 does not tear.

After the completion of the first drawing process, the aluminum sheet 14 can be shifted and repositioned with complete variability in center-to-center distance. This variability is also given in every further drawing process.

During the drawing process, the preselected temperatures of the heatable tool elements must be maintained in a controlled manner. A readjustment may be necessary. It follows that the drawing process can be discontinuous.

Different temperature controls may be necessary between the blank holder 3 and the sheet metal counterholder 7 and between the drawing punch 2 and the die part 9, since the different deformation forces in the areas of the drawing punch radius 15 and sheet metal counterholder radii 16 must be compensated. It may also be necessary that the temperature guides as a whole and among themselves during the drawing process changing deformation work must be adapted.

Reference List

1

first base plate

2

heatable drawing die

3

first heatable hold-down device

4

first coolable hold-down device

5

first hold-down cylinder

6

second base plate

7

heatable sheet metal holder

8th

second hold-down cylinder

9

heatable die part

10

second coolable hold-down device

11

non-coolable pressure absorbing body

12

non-coolable pressure distribution body

13

pressure-resistant insulating material

14

aluminum sheet

15

drawing punch radius

16

sheet metal holder radius

18

pressure release body

20

Aluminum sheet molding

21

deepening

22

side panel

23

opening area

24

Fixed width bridge

25

Variable width bridge

26

Variable width bridge

Claims (13)

1. A method for thermoforming aluminum sheets (14) by means of stretch forming in a device for thermoforming aluminum sheets (14) by means of stretch forming, comprising a pressing device having a thermoforming/stretch forming tool which comprises a first tool, in particular a lower tool, and a second tool, in particular an upper tool, which can be closed with a positive fit with the first tool, wherein the first tool comprises a first base plate (1) having a heatable drawing punch (2), at least one first heatable hold-down device (3), at least one first coolable hold-down device (4) and at least one pressure-adjustable first hold-down cylinder (5), wherein the second tool comprises a second base plate (6) having a heatable die part (9), at least one heatable sheet counterhold (7), at least one second coolable hold-down device (10) and at least one pressure-adjustable second hold-down cylinder (8), wherein the first base plate (1) or the second base plate (6) is fastened to a movable, in particular distance-controlled and force-controlled, device of the pressing device, wherein a holding down of an edge of an aluminum sheet (14) and a stretch forming via the heatable die part (9) are made possible by means of the first and second tools, wherein the heatable and coolable tool elements (2, 3, 4, 7, 9, 10) are heated up or cooled down to their respectively predefined temperatures, after the predefined temperatures are reached, an aluminum sheet (14) to be formed is introduced in the correct position between the first tool and the second tool, and the thermoforming tool is closed with a positive fit, wherein, when the aluminum sheet (14) has reached its predefined temperature under the action of the heat of the heated tool elements (2, 3, 7, 9), the stretch forming movement of the movable tool is started and is carried out up to a predefined drawing depth.
2. The method according to Claim 1, characterized in that, following a stretch forming operation, the aluminum sheet (14) is repositioned and a further, similar stretch forming operation is carried out on a part of the aluminum sheet which has not yet been stretch formed.
3. The method according to Claim 1 or 2, characterized in that the predefined temperatures of individual or all of the tool elements (2, 3, 4, 7, 9, 10) and/or of the aluminum sheet (14) are monitored during a stretch forming operation and the stretch forming movement is interrupted if one or more of the temperatures move(s) outside a predefined acceptable temperature range, and is continued when all of the monitored temperatures are located again within their predefined acceptable temperature ranges.
4. The method according to any one of Claims 1 to 3, characterized in that different temperature controls are utilized between the at least one first hold-down device (3) and the at least one sheet counterhold (7) as well as between the drawing punch (2) and the die part (9) in order to compensate for different change in shape forces in the areas of the drawing punch radius (15) and sheet counterhold radii (16).
5. The method according to any one of Claims 1 to 4, characterized in that the temperature controls of the heatable tool elements (2, 3, 7, 9) are adapted overall and among one another during a stretch forming operation due to varying change in shape work.
6. The method according to any one of Claims 1 to 5, characterized in that the heatable tool elements (2, 3, 7, 9) are heated up to a predefined temperature between 515°C and 540°C.
7. The method according to any one of Claims 1 to 6, characterized in that a pressure is set in the at least one first hold-down cylinder (5), which guarantees that the aluminum sheet (14) is secured during the stretch forming operation and/or a pressure is set in the at least one second hold-down cylinder (8), which guarantees the afterflow of the aluminum sheet (14) during the stretch forming operation.
8. The method according to any one of Claims 1 to 7, characterized in that a non-coolable pressure receiving body (11) is arranged in the first tool and a non-coolable pressure distribution body (12) is arranged in the second tool, which are, in particular, adapted in cross-section to the dimensions of the drawing punch (2) and of the die part (9).
9. The method according to any one of Claims 1 to 8, characterized in that pressure-resistant insulation materials (13) are in each case located between the heatable tool elements (2, 3, 7, 9) and the coolable tool elements (4, 10) and/or the non-coolable tool elements (11, 12).
10. The method according to any one of Claims 1 to 9, characterized in that the heatable tool elements (2, 3, 7, 9) each have one or more heating cartridges.
11. The method according to any one of Claims 1 to 10, characterized in that the heatable tool elements (2, 3, 7, 9) each have their own temperature regulation, in particular with their own data storage.
12. The method according to any one of Claims 1 to 11, characterized in that one or more of the heatable tool elements (2, 3, 7, 9) and/or one or more of the coolable tool elements (4, 10) have one or more temperature sensors which are arranged, in particular near the surface or in the surface facing the aluminum sheet (14), such that a temperature of the aluminum sheet (14) can be established in the area of the respective temperature sensor.
13. The method according to any one of Claims 1 to 12, characterized in that a distance measuring device is provided on the thermoforming/stretch forming tool which is designed and adapted to adjust the movement and speed of the moving first or second tool with respect to the non-moving second or first tool, in conjunction with the movable distance-controlled and force-controlled device of the pressing device as well as the temperature control of the heatable tool elements (2, 3, 7, 9), wherein during the movement of the movable tool during the distance and force control, both the distance covered by the drawing punch or, respectively the movable tool and the force applied for this are measured and compared with nominal values, wherein when a predefined value corridor is left, the process is interrupted in order to bring the material of the aluminum sheet back to the predefined temperature, in that the applied force also returns to the predefined value corridor.

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