DE102020106743B3 - Dishing tool, dishing press and method for producing a container bottom - Google Patents

Abstract

The invention relates to a dishing tool (14) with an upper tool (15) and a lower tool (16), the upper tool (15) having a pressure piece (60) with a first shape contour (64) for contacting a workpiece (30) and one relative to the Pressure piece (60) comprises movable hold-down device (50) with a second shaped contour (58) for contacting the workpiece (30), the hold-down device (50) being arranged concentrically around the pressure piece (60). The upper tool (15) also has a head plate (40) for connection to a ram of a press, the pressure piece (60) being firmly connected to the head plate (40) or made in one piece with the head plate (40) and the hold-down device (50) ) is connected to the head plate (40) via at least one elastic element (52) and is arranged relative to the pressure piece (60) in such a way that the second shaped contour (58) protrudes beyond the first shaped contour (64), so that when the Upper tool (15) in the direction of a workpiece (30), the workpiece (30) is first contacted by the second shape contour (58). The upper tool (15) is set up in such a way that when the upper tool (15) moves further in the direction of the workpiece (30), the pressure piece (60) is moved further in the direction of the workpiece (30) relative to the hold-down device (50) at least one elastic element (52) is compressed. Further aspects of the invention relate to a dishing press and a method for producing a container bottom.

Description

The invention relates to a dishing tool comprising an upper tool and a lower tool, the upper tool comprising a pressure piece with a first shape contour for contacting a workpiece and a hold-down device movable relative to the pressure piece with a second shape contour for contacting the workpiece, and the hold-down device concentrically around the pressure piece is arranged. Further aspects of the invention relate to a dishing press which comprises such a dishing tool, as well as a method for producing a container bottom.

State of the art

When metal sheets are formed by means of bulging, curved shaped parts are obtained from the sheets with little or no change in the material thickness. The dishing is used, for example, in the manufacture of container bottoms from round metal sheets, also known as circular blanks. For dishing, dishing presses are used which comprise a rigid upper tool with a spherically convex forming side and a likewise rigid lower tool with a spherically concave forming side. In many pressing processes, the circular blanks are pressed to the desired spherical radius between the upper tool and the lower tool. If deep workpieces are produced from the metal sheets in which the metal sheet thickness is small in relation to the diameter of the round blank, wrinkles are formed in the sheet metal during the forming process. It is known from the deep-drawing process that the formation of creases can be prevented by using a sheet metal holder, which holds the entire edge area of the circular blank in order to avoid creases on the decorative ring.

the end DE 24 58 012 A1 a so-called bottom dishing press is known which has an inner ram and an outer ram. A sheet metal holder is attached to the outer ram and the ram is attached to the inner ram. The press ram and the hold-down device can be moved separately from one another via a hydraulic double-acting press and are each set up to accommodate sheet metal hold-down devices or drawing rings of different sizes. In this process, the pressed parts are brought to their finished size by pulling the press ram through the drawing ring.

The end DE 24 58 012 A1 known processes are not to be assigned to the dishing process for the purposes of the present invention. In a dishing process within the meaning of the invention, the round blank used, i.e. the workpiece to be reshaped, is larger than the pressing tool used and the workpiece is brought into the desired shape by means of many partial pressing processes to be carried out one after the other. In a deep-drawing process, which also includes that DE 24 58 012 A1 belongs to the method described, the round blank is smaller than the pressing tool and the workpiece is formed in one pressing operation.

the end US 9,833,828 B2 an apparatus for deep drawing is known. A press tool apparatus comprises, in addition to an upper and lower die, holding elements for a workpiece, an upper holding element being connected to a base via elastic elements.

DE 14 52 913 A describes a method for manipulating heavy round blanks when operating dishing presses. Provision is made here to grasp and support the round blank at the edge areas with tools, with vertical movements as well as lateral and / or rotary movements being carried out mechanically.

Disclosure of the invention

A dishing tool comprising an upper tool and an associated lower tool is proposed. The upper tool of the dishing tool comprises a pressure piece with a first shape contour for contacting a workpiece and a hold-down device movable relative to the pressure piece with a second shape contour for contacting the workpiece, the hold-down device being arranged concentrically around the pressure piece. The upper tool also has a head plate for connection to a ram of a press, the pressure piece being firmly connected to the head plate or made in one piece with the head plate and the hold-down device being connected to the head plate via at least one elastic element and thus arranged relative to the pressure piece that the second form contour protrudes beyond the first form contour, so that when the upper tool moves in the direction of a workpiece, the workpiece is first contacted by the second form contour. The upper tool is also set up in such a way that upon further movement of the upper tool in the direction of the workpiece, the pressure piece is moved further in the direction of the workpiece relative to the hold-down device, the at least one elastic element being compressed.

The hold-down device is thus coupled to the pressure piece via the at least one elastic element in such a way that both can be moved towards the workpiece via a single ram of a press. The hold-down protrudes beyond the pressure piece so that the workpiece is first contacted by the hold-down. As a result, the workpiece is subjected to a contact pressure which exceeds the properties of the at least one elastic element is defined, pressed against a lower tool and thus fixed before the pressure piece of the upper tool touches the workpiece.

Advantageously, the pressure with which the hold-down presses on the workpiece increases with the depth of the deformation due to the coupling via the at least one elastic element. The deeper the pressure piece is pressed into the workpiece, the more the at least one elastic element is compressed and the stronger the pressure exerted by the hold-down device.

This pressure exerted by the hold-down device can easily be adjusted by appropriate selection of the at least one elastic element.

The proposed upper tool, in combination with a corresponding lower tool, allows a workpiece to be fixed from the start of machining, so that it cannot evade the upper tool. Furthermore, the fixing of the area of the workpiece around the pressure piece prevents or at least reduces the formation of wrinkles in the workpiece during the deformation.

The at least one elastic element is preferably selected from the group comprising elastomer springs, steel springs and gas pressure springs. Furthermore, combinations of several of these elastic elements are also conceivable.

In the case of elastomer springs, an elastic element is designed, for example, as a cylinder made of an elastomer. Suitable elastomers include, for example, polyurethane and natural or synthetic rubber (rubber). The elastomer springs are preferably made from polyurethane. An elastic element can also be composed of several individual parts. For example, an elastic element can be designed from a plurality of cylindrical parts stacked on top of one another and / or a plurality of parts designed as cylinders can be arranged next to one another.

The upper tool preferably has elastic elements in the range from 4 to 36. The upper tool particularly preferably has elastic elements in the range from 10 to 25 and particularly preferably in the range from 10 to 24.

The elastic elements are preferably designed and arranged such that all elastic elements together exert a spring force in the range of 100,000 N to 1,500,000 N (approx. 10 t to 150 t weight force) as a hold-down force with a spring deflection of, for example, 30 mm. This hold-down force is transferred from the upper tool to the workpiece that is picked up during operation.

An example of a suitable spring element is a spring element made up of two superimposed cylindrical elastomer springs of the type Fibro 246.6.063.125. Such elastomer springs are according to DIN ISO 10069-1 Available in different sizes and degrees of hardness from Fibro GmbH. For example, the elastomer springs of the type 246.6.063.125 each have a maximum spring deflection of 37.5 mm, so that such a composite spring element has a maximum spring deflection of 75 mm. In this example, the maximum possible relative movement between the hold-down device and the pressure piece is limited to 60 mm with a mechanical stop.

Due to the coupling via the at least one elastic element, the force exerted by the hold-down device is essentially proportional to the distance by which the at least one elastic element has been compressed. This distance corresponds to the distance covered by the upper tool in the direction of the workpiece from when the hold-down device is placed on the workpiece. With real spring elements, such as elastomer springs, there are deviations from this idealized proportional behavior, especially over long distances with regard to the maximum possible spring deflection of the corresponding spring element.

Before it is placed on the workpiece, the hold-down protrudes preferably by a distance in the range from 10 mm to 120 mm, particularly preferably in the range from 20 mm to 80 mm, beyond the pressure piece. This distance is related to the transition area where the hold-down device and the pressure piece touch. In relation to the lowest point of the hold-down device and the lowest point of the pressure piece, the length of the protrusion is preferably in the range from 3 mm to 5 mm.

The distance and thus a relative movement between the hold-down device and the pressure piece can be limited, for example, by providing a mechanical stop. When the stop and thus the maximum distance are reached, the hold-down device follows the movement of the pressure piece again, the force exerted by the hold-down device then corresponding to the force exerted by the pressure piece.

The pressure piece of the upper tool has a first shape contour and the hold-down device of the upper tool has a second shape contour. The respective shape contours represent the surfaces of the upper tool that are set up for contacting the workpiece as part of a forming process. Correspondingly, the first shaped contour of the pressure piece in particular has a Shape that corresponds to the shape that is to be impressed on the workpiece by the forming process.

The first shape contour and / or and the second shape contour is preferably spherical. A corresponding upper tool is thus set up to spherically reshape a workpiece or a region of the workpiece contacted by the upper tool.

The first shape contour and the second shape contour are particularly preferably each spherical. It is preferred here if the first shape contour and the second shape contour each have the same radius. The shapes of the hold-down device and the pressure piece are preferably selected in such a way that the first mold contour and the second mold contour merge seamlessly into one another when the upper tool is completely pressed into a corresponding lower tool. If necessary, a small gap can be formed between the first shape contour and the second contour.

The radius of the first and / or the second shape contour is selected in the range from 500 mm to 5000 mm, for example. The radius is preferably selected in the range from 1500 mm to 5000 mm.

The lower tool of the dishing tool has a third shape contour which is set up to contact a workpiece during a forming process. The third shape contour is preferably spherical and selected with a gap dimension corresponding to the maximum pressed part thickness as a counterpart to the first and second shape contour of the upper tool. Accordingly, the third shape contour is preferably designed spherically concave and interacts with the first and second shape contour, which is preferably designed spherically convex. The amount of the radius of the third mold contour is designed as a function of the maximum pressed part thickness.

Another aspect of the invention is the provision of a dishing press which comprises one of the dishing tools described herein.

The dishing press comprises a driven ram to which the upper tool is attached and an oppositely arranged receptacle to which the lower tool is attached. The upper tool can be moved in the direction of the lower tool via the driven ram, so that a workpiece arranged between the upper tool and the lower tool can be machined with the tools. The dishing press preferably comprises exactly one driven ram which moves both the pressure piece and, indirectly via the at least one elastic element, the hold-down device of the upper tool.

The ram can be driven hydraulically, for example.

The dishing press further preferably comprises a manipulator which is set up to move a workpiece relative to the tool. In this way, very large workpieces can also be machined, with a large number of individual pressing steps being carried out to reshape this workpiece. A pressing step is carried out in each case, in which the upper tool is pressed into the lower tool and part of the workpiece is reshaped. After each pressing step, the upper tool is withdrawn again via the ram and the workpiece is moved on via the manipulator.

The manipulator is designed, for example, as a plurality of driven wheels on which the workpiece rests. The workpiece can then be moved relative to the dishing tool by driving the wheels. The position and / or the angle of the wheels can be adjustable in order to adapt the manipulator to different workpieces and the respective processing progress.

Another aspect of the invention is the provision of a method for producing a container bottom. In a first step a) of the method, a round blank is provided as a workpiece. In a subsequent step b) of the method, the round blank is shaped into a spherically curved shaped part by means of dishing using the dishing tool described herein. The dishing tool accordingly comprises one of the upper tools described herein, so that when the round blank is formed, it is first fixed by the hold-down device of the upper tool and is then pressed against the lower tool by a pressure piece of the upper tool and formed.

Step b) is preferably followed by a further process step c) in which an edge of the spherically curved molded part is flanged. In this crimping process, a corner radius and a cylindrical rim are formed.

A container base produced in this way is a curved base, consisting of a central spherical cap, a circumferential corner radius and a cylindrical rim.

The container bottom is particularly suitable for use on a cylindrical pressure vessel jacket. To produce such a container, a further step d) follows the method, in which a cylindrical pressure container jacket is connected to the container bottom, for example by means of welding.

The provision of the round blank in accordance with step a) can take place, for example, by cutting out a round, disc-shaped piece from a metal sheet. Circular scissors or a burning system, for example, can be used for this purpose.

A large number of metallic materials are used for the circular blanks. These are preferably ferritic or austenitic alloys or steels as well as aluminum or aluminum alloys. In principle, all ductile materials with sufficient elongation can be formed in this way.

Typical thicknesses of a round blank are in the range from 2 to 20 mm.

In step b) of the method, the round disk or the blank is shaped into a curved molded part with a spherical segment shape. This is done step by step by gradually pressing the round blank between the upper tool and the lower tool to the desired spherical radius. This radius is specified by the shape contours of the dishing tool, so that the tool is selected accordingly.

In the method, it is provided according to the invention that the upper tool used has a hold-down device that is movable relative to the pressure piece, the hold-down device and the pressure piece being coupled via at least one elastic element. The hold-down initially protrudes beyond the pressure piece, so that the workpiece is first contacted by the hold-down. As a result, the workpiece is pressed against a lower tool with a contact pressure, which is defined by the properties of the at least one elastic element, and thus fixed before the pressure piece of the upper tool touches the workpiece. After the hold-down fixes the workpiece against the lower tool, the pressure piece is also pressed against the workpiece by further approaching the upper tool, so that it brings the workpiece to the desired radius. The radius is specified by choosing the shape of the dishing tool.

The pressure of the blank holder on the workpiece increases with the depth of the deformation during the pressing due to the coupling via the at least one elastic element. The deeper the pressure piece is pressed into the workpiece, the more the at least one elastic element is compressed and the stronger the pressure exerted by the hold-down device. The pressure exerted by the hold-down device is adjusted by appropriate selection of the at least one elastic element.

In the reshaping according to step b), depending on the size of the base to be produced, it may be necessary to change the position of the blank or the workpiece relative to the dishing tool, the blank being gradually reshaped. A manipulator, which can change the position of the workpiece relative to the tool in a controlled manner, is preferably used to handle the round blank or the workpiece. After each pressing with the dishing tool, the upper tool of the dishing tool is withdrawn from the workpiece, the position of the workpiece is changed and the workpiece is machined again with the dishing tool. These steps are repeated until the desired reshaping of the blank is achieved.

By providing the hold-down device, the workpiece or the round blank is fixed during the pressing and cannot evade the deformation forces which are transmitted by the pressure piece. Undesired wrinkling in the workpiece is also prevented.

Such wrinkling occurs during forming without a hold-down device, since these conventional dishing tools pull the edge of the round blank to a smaller final diameter. Particularly in the starting phase, when the circular blank is still flat, extreme wrinkling occurs, since the meridian membrane tension in the circular blank creates radial compressive stresses. With such thin round blanks, however, the radial compressive stresses do not lead to an upsetting process to a smaller diameter. As the diameter becomes smaller, the pressed part tries to maintain its original circumference. The pressed part can achieve this in that it folds the edge area in particular. In the starting phase, when a conventional dishing tool is used, the creases appear when the upper tool only presses a few millimeters into the lower tool. The folds then begin in an area directly below the upper tool.

Because of this wrinkling when conventional tools are used, the upper tool cannot be pressed completely into the lower tool. The result is that the round blank or the workpiece assumes a position in which the stresses are distributed as evenly as possible and do not assume high values. Since a stress greater than the upper yield point or the yield point has to be generated for every permanent deformation, the gain in shape change is often small. A large part of the deformation in the workpiece remains below the yield point, i.e. within the elastic range, and springs back into the old position after the load is removed.

By using the proposed dishing tool with the hold-down device, the workpiece is fixed from the start of machining, which means that it cannot avoid the dishing tool. This leads to better control of the formation of wrinkles, since the forming area is clamped. Due to the significant reduction in the formation of wrinkles, the upper tool can also be pressed completely into the lower tool, so that the deformation obtained is greater. The yield point of the material of the workpiece is reached and exceeded over a larger area and more easily. The forming step can be carried out using the proposed dishing tool with a smaller number of pressing steps. This results in significantly shorter forming times in the manufacture of the workpiece. Furthermore, frequent tool changes and the associated conversion times can be reduced, since greater degrees of deformation can be achieved with the proposed dishing tool.

Figure list

Embodiments of the invention are explained in more detail with reference to the drawings and the following description.

• 1 eine schematische Darstellung einer Kümpelpresse,
• 2 ein Kümpelwerkzeug nach dem Stand der Technik,
• 3a ein erfindungsgemäßes Kümpelwerzeug mit einem Niederhalter in Klemmposition und
• 3b das erfindungsgemäße Kümpelwerkzeug mit vollständig in das Unterwerkzeug gepresstem Oberwerkzeug.

Show it:

• 1 a schematic representation of a dishing press,
• 2 a state-of-the-art dishing tool,
• 3a a Kümpelwerzeug according to the invention with a hold-down device in the clamping position and
• 3b the dishing tool according to the invention with the upper tool pressed completely into the lower tool.

Embodiments of the invention

In the following description of the embodiments of the invention, the same or similar elements are denoted by the same reference numerals, a repeated description of these elements being dispensed with in individual cases. The figures represent the subject matter of the invention only schematically.

1 shows a schematic representation of a dishing press 10 . The dishing press 10 includes a driven ram 12th on which an upper tool 15th is attached. Opposite the upper tool 15th is a lower tool 16 arranged. The lower tool 16 and the upper tool 14th together form a dishing tool 14th the end.

For reshaping a workpiece 30th this is between the upper tool 15th and the lower tool 16 placed. Via the driven ram 12th can the upper tool 15th towards the lower tool 16 be moved so that the workpiece 30th with the dishing tool 14th can be edited.

The dishing press 10 further comprises a manipulator 20th that is used to move the workpiece 30th relative to the dishing tool 14th is set up. In this way, workpieces can also 30th which are larger than the dishing tool 14th are. A large number of individual pressing steps are used to reshape this workpiece 30th carried out, a pressing step being carried out in each case in which the upper tool 15th in the lower tool 16 is pressed. After each pressing step, the upper tool becomes 15th over the plunger 12th withdrawn again and the workpiece 30th via the manipulator 20th moved on.

The manipulator 20th is for example as multiple driven wheels 22nd designed on which the workpiece 30th rests. By driving the wheels 22nd can then the workpiece 30th relative to the dishing tool 14th be moved. The position and / or angle of the wheels 22nd is adjustable to the manipulator 20th on different workpieces 30th and to adapt the respective processing progress. 2 shows a dishing tool 14th according to the state of the art. The dishing tool 14th has an upper tool 15th and a corresponding lower tool 16 on. A workpiece is used for forming 30th between the upper tool 15th and the lower tool 16 placed. By pressing the upper tool 15th in the lower tool 16 a forming pressure is applied to the workpiece 30th exercised.

The problem here is that the workpiece 30th can move unintentionally. It also happens, especially when the sheet metal thickness of the workpiece 30th in relation to the diameter of the workpiece 30th is low, after the previous forming 2 to a significant wrinkle formation in the pressed part.

In the 3a and 3b is a dishing tool according to the invention 14th with an upper tool 15th and a corresponding lower tool 16 shown.

The upper tool 15th includes a pressure piece 60 with a first shape contour 64 and a hold-down 50 with a second shape contour 58 . The radius of the third mold contour is designed depending on the maximum pressed part thickness.

The pressure piece 60 is solid and direct with a headstock 40 tied together. The headstock 40 is set up with a movable plunger 12th , compare 1 to be connected.

The hold-down 50 is like this on the upper tool 15th arranged that this relative to the pressure piece 60 is movable. The hold-down 50 is about several elastic elements 52 with the headstock 40 tied together. The elastic elements 52 can be compressed by the application of force and allow the hold-down to do so 50 on contact with a workpiece 30th to stop. The pressure piece moves on in a movement relative to the hold-down device and presses the workpiece 30th in the lower tool 16 .

For guiding a relative movement of the hold-down device 50 this is for example via a bronze bushing (not shown) on the pressure piece 60 guided. A protective cover 42 closes the moving parts of the upper tool 15th to the outside and in particular prevents the ingress of dirt.

To limit the relative movement between the hold-down device 50 and the pressure piece 60 a mechanical stop is provided in the illustrated embodiment. This is on the pressure piece 60 a collar 62 trained with one shoulder 56 on the hold-down device 50 cooperates when the upper tool 15th like in the 3b completely sketched in the lower tool 16 is pressed.

To accommodate the elastic elements 52 are in the hold-down 50 Recesses 54 intended. The elastic elements 52 are designed, for example, as elastomer springs.

The hold-down 50 of the upper tool 15th protrudes over the pressure piece in an unloaded state 60 addition, so that when the upper tool approaches 15th to the workpiece 30th this first from the second shape contour 58 of the hold-down device 50 is contacted. This will make the workpiece 30th with a contact pressure which is based on the properties of the at least one elastic element 52 is defined against the third shape contour 72 of the lower tool 16 pressed and thus fixed before the pressure piece 60 of the upper tool 15th the workpiece 30th touched. the 3a shows the dishing tool 14th in a position in which the workpiece 30th through the hold-down device 50 is fixed. After the hold-down 50 the workpiece 30th against the lower tool 16 has pressed and thus fixed, is made by further approaching the upper tool 15th to the lower tool 16 also the pressure piece 60 with its first shape contour 64 against the workpiece 30th pressed. Through the first shape contour 64 and the third shape contour 72 are deformation forces on the workpiece 30th exercised that this is brought to the desired radius. The radius is determined by the choice of the shape contours 64 , 72 of the dishing tool 14th given. the 3b shows the dishing tool 14th in a position in which the upper tool 15th completely into the lower tool 16 is pressed.

The pressure piece 60 immersed in a relative movement to the hold-down during the pressing process 50 deep into this one until the stop 62 is achieved. In this position hold-downs form 50 and pressure piece 60 a rigid unit in the axial pushing direction. In this end position, form the radius on the pressure piece 60 and the same radius on the hold-down device 50 a spherically matching unit.

In the schematic representations of the 2 as well as 3a and 3b is the lower tool 16 each shown larger than the upper tool 15th . The size of the lower tool is preferred 16 chosen so that this corresponds to the size of the upper tool 15th corresponds to how this is in the 1 is shown schematically.

The invention is not restricted to the exemplary embodiments described here and the aspects emphasized therein. Rather, a large number of modifications are possible within the range specified by the claims, which are within the scope of expert action.

List of reference symbols

10

Press

12th

Plunger

14th

Dishing tool

15th

Upper tool

16

Lower tool

20th

manipulator

22nd

driven wheel

30th

workpiece

40

Headstock

42

Protective cover

44

Recess

50

Hold-down

52

Spring element

54

Recess

56

shoulder

58

second shape contour

60

Pressure piece

62

collar

64

first shape contour

72

third shape contour

Claims (9)

Dishing tool (14) with an upper tool (15) and a lower tool (16), the upper tool (15) having a pressure piece (60) with a first contour (64) for contacting a workpiece (30) and a pressure piece (60) relative to the pressure piece (60) movable hold-down device (50) with a second contour (58) for contacting the workpiece (30), the hold-down device (50) being arranged concentrically around the pressure piece (60), characterized in that the upper tool (15) also has a head plate (40) for connection to a ram (12) of a press (10), wherein the pressure piece (60) is firmly connected to the head plate (40) or is made in one piece with the head plate (40) and the hold-down device (50) has at least an elastic element (52) is connected to the head plate (40) and is arranged relative to the pressure piece (60) in such a way that the second mold contour (58) protrudes beyond the first mold contour (64), so that when the upper tool (15 ) in the direction of a workpiece (30) the workpiece (30) is first contacted by the second mold contour (58), and the upper tool (15) is set up in such a way that when the upper tool (15) moves further in the direction of the workpiece (30), the pressure piece ( 60) is moved further in the direction of the workpiece (30) relative to the hold-down device (50), the at least one elastic element (52) being compressed. Dishing tool (14) Claim 1 , characterized in that the at least one elastic element (52) is selected from the group comprising elastomer springs, steel springs, gas pressure springs and combinations of several of these elastic elements. Dishing tool (14) Claim 1 or 2 , characterized in that the upper tool has elastic elements (52) in the range from 4 to 36. Dishing tool (14) according to one of the Claims 1 until 3 , characterized in that all elastic elements (52) taken together exert a spring force in the range of 100,000 N to 1,500,000 N as a hold-down force with a spring deflection of 30 mm. Dishing tool (14) according to one of the Claims 1 until 4th , characterized in that the first shape contour (64) and / or and the second shape contour (58) is spherical. Dishing tool (14) Claim 5 , characterized in that the first shape contour (64) and the second shape contour (58) are each spherical and have the same radius, the first shape contour and the second shape contour when the upper tool (15) is completely pressed into a corresponding lower tool (16) ) merge seamlessly into one another. Dishing press (10) comprising a dishing tool (14) according to one of the Claims 1 until 6th . A method for producing a container base comprising a) providing a round blank b) forming the round blank into a curved shaped part by means of dishing using a dishing tool (14) according to one of the Claims 1 until 6th comprising an upper tool (15) and a lower tool (16), the blank being first fixed by a hold-down device (50) of the upper tool (15) and then by a pressure piece (60) of the upper tool (15) against the lower tool (16) ) is pressed and formed. Procedure according to Claim 8 , characterized in that after the reshaping according to step b) in a further step c), an edge of the curved molded part is flanged.

Images