METHOD AND PRESS FOR INTRODUCING A DEFORMATION PATTERN INTO A SHEET

Description

The invention relates to a method for introducing a deformation pattern into a sheet, in particular made of metal, using at least one tool unit of a press. The invention also relates to a press.

In the prior art, it is widespread to provide sheets of metal with a deformation pattern. For this purpose, according to the previous prior art, a deformation pattern desired in the sheet is provided as a corresponding deformation structure on an upper and a lower forming die in order to transfer the deformation pattern onto the sheet lying between the dies by guiding the forming dies in the press together. The dies are also designated male and female dies. This principle is also used in the invention.

One area of application, in which the invention is preferably also used, is the production of electrolyser plates, in particular so-called “interconnects” for electrolysers, or else the production of fuel cell plates or bipolar plates. Such plates frequently have deformed geometries, for example embossings and/or deep-drawn regions, and also die-cuts and are used in a stacked design, for example in electrolysers or else in fuel cells. Frequently, the deformed regions and/or die-cuts define those areas in the plates in which a fluid is guided. Die-cuts frequently define those areas in which a fluid is guided between different planes of a plate stack, and deformations, e.g. embossings, define those areas in which a fluid is guided within a plane of the plate, parallel to the plane or around the latter. Such plates can also have deformations or die-cuts which are not used for fluid guidance, for example for assembly purposes. In such plates, the so-called flow field defines a particularly large locally coherent region of channels or channel sections for fluid guidance, which forms a sub-area of an overall deformation pattern. The invention is thus preferably used in plates of electrolysers or fuel cells which have such a flow field.

According to the previous prior art, at least the flow field areas of such plates are produced in a single stroke of a tool unit of a press, which also includes the precision cutting devices preferably used here. Both the deformations and also the die-cuts can preferably be carried out in one stroke.

The problem is that, with increasing size of a deformation pattern or with increasing number of depressions/elevations relative to the plane of the sheet, e.g. in an electrolyser plate or bipolar plate or fuel cell plate, the forces needed for the deformation rise significantly, so that a desired deformation pattern can no longer be produced in a single stroke using conventional presses. In particular, electrolyser plates have far larger areas than plates of fuel cells, so this problem is particularly relevant in electrolyser plates.

The trend to enlarging electrolyser plates or bipolar plates/fuel cell plates even leads to the problem that the very production of a sub-area of the entire deformation pattern of such a plate, such as of the flow field, for example, can no longer be implemented with existing presses of conventional design or at least not in an economically justifiable way or not with the required precision.

It is therefore an object of the invention to provide a method for introducing a deformation pattern into a sheet which can be implemented with current presses and tool units used therein. In particular, it is to be made possible in electrolyser plates or bipolar plates/fuel cell plates to be able to produce the sub-area of the flow field of the entire deformation pattern, preferably the entire deformation pattern, in particular also with supplementary die-cuts, in an economically practical way on current commercially obtainable presses. In particular, the production of electrolyser plates and/or fuel cell plates/bipolar plates is thus to be improved or simplified.

This object is achieved in that the deformation pattern in at least one sub-area has a plurality of identical pattern units lying beside one another with a pattern spacing in at least one pattern direction, and the press for deforming only the sub-area comprises a tool unit in which an upper and a lower forming die are arranged, with the interacting deformation structures of which at least one pattern unit of the sub-area is formed in a single stroke of the tool unit in the sheet guided between the forming dies and, between two successive strokes of a predetermined total number of strokes of the tool unit, the sheet is transported onward within the tool unit in a conveying direction corresponding to the at least one pattern direction and, in the tool unit, with each stroke of the predetermined total number, the pattern introduced/formed in the sheet is supplemented by at least one introduced pattern unit until, after the predetermined total number of strokes, the sub-area of the deformation pattern has been completed. A tool unit can preferably comprise still further tools which participate in the method in addition to the forming dies.

Preferably, a single stroke is understood to be the succession of a closing phase of the tool unit, in which the forming dies are moved toward each other, and of an opening phase of the tool unit, in which the forming dies are moved away from each other.

The deformation by means of the forming dies is carried out, for example, by deep-drawing and/or embossing the sheet, produced during the closing phase of the tool unit, in particular by embossing which follows deep-drawing, preferably in the same stroke of the tool unit.

The conveyance of the sheet within the tool unit between two strokes, in particular between two closing phases, is preferably carried out by means of a conveying device, in particular which is provided in the press or in the tool unit. Preferably, the conveying device effects the conveyance of the sheet during and/or after the opening phase of a stroke.

The invention makes use of the fact or can be applied when an overall deformation pattern to be produced can be broken down into a plurality of sub-areas which can be produced one after another, wherein the invention provides here for at least one such sub-area in the deformation pattern which can be divided up into a plurality of identical pattern units to be provided or identified, wherein the pattern units are arranged to lie beside one another in the sub-area and the pattern units have a constant pattern spacing from one another.

In particular in an electrolyser plate or fuel cell plate, such a sub-area that can be subdivided into a plurality of pattern units can be formed by the so-called flow field, in which a fluid can be guided within the electrolyser or fuel cell assembled from a plurality of such plates. Preferably, such an electrolyser plate or fuel cell plate also comprises further deformed or die-cut regions, in particular which are arranged on the outside around the flow field, in addition to the flow field.

In such a flow field, for example, specific channel-forming pattern regions can occur repeatedly beside one another. Such repeating pattern regions each form a pattern unit in the sense of the invention.

In particular, provision is made for there to be only a single conveying direction in which the sheet is transported in the tool unit, preferably if the aforementioned sub-area comprises only those pattern units which lie beside one another in a single pattern direction. However, if the sub-area has pattern units which lie beside one another in at least two pattern directions, e.g. in two mutually perpendicular pattern directions, then provision can also be made for the sheet in the tool unit to be moved onward between two strokes in one of the at least two pattern directions or in a conveying direction combined from the at least two pattern directions.

According to the invention, this method opens up the possibility of reducing the process forces needed for the deformation since, with each stroke, only a small part of the sub-area in the deformation pattern which is repeatedly present in the sub-area is introduced and formed in the sheet. Thus, even very large flow field arrangements in electrolyser plates or bipolar plates/fuel cell plates can be produced with comparatively small presses. This is therefore very economically reproducible with the invention since, for the deformation of such a sub-area, the same pairing of upper and lower forming dies in the same tool unit can be used again and again until the whole of the sub-area has been completed.

If there is a sub-area with a specific total number of pattern units in the deformation pattern, the invention can thus provide to deform this sub-area with up to a maximum number of strokes which corresponds to the total number. In this case, each pattern unit is formed in its own individual stroke.

On the other hand, an embodiment is viewed as preferable according to which, with the interacting deformation structures of the lower and upper forming dies of the tool unit, a number N of pattern units of the sub-area are formed simultaneously in a single stroke of the tool unit, where N>=2. The number N is preferably a whole number greater than 15%, more preferably greater than 20%, of the total number of all the pattern units in the sub-area.

Preferably, depending on the maximum of the deformation forces that can be generated in the tool unit, the maximum subset of all the pattern units that can be formed in a single stroke is determined, in order in this way to minimize the necessary number of strokes.

A preferred development provides that, after a stroke of the tool unit, as a result of the onward transport of the sheet, its introduced pattern, in particular an area of the introduced pattern that has been produced in the preceding stroke, is moved into an at least partial overlap with the deformation structures of the upper and lower forming die.

As a result of this overlap, after the first initial stroke, a new area is formed in the sheet with each further stroke with the forming dies, which area corresponds to the deformation structure of the forming dies minus the overlap area. In the overlap area, the sheet is actually shaped twice, in particular either no or only insubstantial further shaping taking place as a result. However, the overlap preferably effects positioning of the sheet relative to the forming dies, since the overlapping already shaped areas of the sheet are aligned with the deformation structures of the dies, as a result of which the precision of the positioning relative to one another of the areas shaped with each stroke is improved.

In order to achieve the overlap, provision can, for example, be made for the sheet to be moved onward in the conveying direction by M times the pattern spacing, where M<N and N corresponds to the number of pattern units which can be introduced with the forming dies. In this way, an overlap which corresponds to N-M pattern units is preferably always produced.

Also preferably, provision is made that, with each stroke of the tool unit, a positioning geometry is introduced into the sheet and a positioning element is provided in the tool unit or the press, wherein, before and/or with the closing movement of a stroke, the positioning element and the positioning geometry are brought into a predetermined position relative to one another.

The closing movement of a stroke is the movement during which the upper and lower forming dies are moved toward each other.

The positioning geometry can preferably be a die-cut positioning opening. The positioning element can preferably be a positioning pin of which at least a part moves into the positioning opening. The positioning pin can preferably be a constituent part of the tool unit, in particular one of the forming dies, or at least a constituent part of the press which is moved in the stroke.

Preferably, the location at which the positioning geometry is introduced lies in an area of the sheet in which no parts of the sub-area to be repeatedly introduced are located.

This also opens up the advantage of forming or preferably die-cutting the positioning geometry with a die which is located in the tool unit or the press, adjacent to the forming dies. Likewise, the positioning element can be arranged adjacent to the forming dies in the tool unit or the press.

Preferably, provision is made for the positioning opening to be a circular hole and for the positioning pin to have a circular cross section. Provision is preferably made for the pin to taper in the direction of its free end, in particular irrespective of the aforementioned cross-sectional shapes. In particular, provision can be made for the pin to widen from the free end/the tip, starting in the external cross section/diameter, up to an extent which is larger than the internal cross section/diameter of the positioning opening. In this case, the pin cannot penetrate completely through the positioning opening but centres the opening around its tip. The penetration depth is therefore restricted to the tapering tip area, which prevents the pin jamming in the opening and/or makes it easier to pull the pin out of the positioning opening. The positioning pin is preferably resiliently supported in the tool unit or the press in the axial direction of the stroke movement.

A preferred embodiment provides for the positioning geometries each to be arranged in an area of the sheet in which, in a later die-cutting step, in particular which is carried out with another tool unit of the same press or another press, at least one die-cut is introduced, in particular wherein at least one positioning geometry is removed by the at least one die-cut, preferably where a die-cut has a fluid-carrying function in a pack of a plurality of electrolyser plates or fuel cell plates. Preferably, all the previously produced positioning geometries are removed by a plurality of die-cuts. It is thus ensured that the positioning geometry is only a temporary element of the sheet during the processing of the latter, which is no longer present in the subsequently completed sheet.

Preferably, the positioning geometry can be located in a subsequent useful area of an electrolyser plate that is to be produced but is not disruptive, since the positioning geometry is replaced by a die-cut that is needed for the function of the electrolyser plate, e.g. a subsequent fluid-carrying die-cut. Provision is preferably always made for the positioning geometry to be located completely within the cross-sectional area of the same die-cut which removes and/or replaces the positioning geometry. In particular, the die-cut is thus always larger than the positioning geometry.

Preferably, provision is made that an element for introducing the positioning geometry, in particular a hole punch, is arranged in the tool unit, and the positioning element is arranged in the conveying direction at a distance which is smaller than the number of pattern units that can be formed with the forming dies, in particular which corresponds to M x pattern spacing.

In particular, the result is that the distance is smaller than the width of the forming dies, viewed in the conveying direction of the sheet, preferably wherein the width of the forming dies is N x pattern spacing.

The invention preferably provides that, in or with at least one further tool unit, pattern components of the deformation pattern are formed in the sheet and/or die-cuts and/or edge cuts are introduced into the sheet which are not part of the sub-area, in particular are arranged on the outside around the latter.

The further tool unit can be arranged in the same press as the aforementioned tool unit for the repeated forming of the sub-area, in particular as a so-called progressive die, or else in another press, or provision can be made to replace the tool unit for the repeated forming of the sub-area in the same press by the aforementioned further tool unit for forming pattern components which are not part of the sub-area.

In the latter case, the invention preferably thus provides two tool units, wherein the sub-area having repeating pattern units can be formed with a first tool unit and the pattern components of the deformation pattern which are not part of the sub-area, in particular lie around the latter, can be formed in the sheet with a second tool unit, wherein the press is firstly equipped with one of the two tool units, in particular with the first tool unit, and a number of sheets are shaped with this tool and temporarily stored in a buffer, and then the same press is equipped with the other of the two tool units, in particular with the second tool unit, and sheets are removed from the buffer and the removed sheets are shaped with the other tool unit. In the method, the two tool units are thus used alternately in the press, in particular it being irrelevant which of the tool units is used first.

The at least one further tool unit can carry out machining chronologically before the aforementioned tool unit, but provision is preferably made for it to perform the machining of the sheet chronologically after the forming of the at least one sub-area, in particular wherein the sheet is completed by using the at least one further tool unit in a single stroke in addition to the total number of strokes for forming the at least one sub-area.

Completed preferably means only that further machining of the sheet with the press is no longer envisaged. On the other hand, further machining can be provided in other machining stations.

In particular, following the machining of the sheet by the at least one further tool unit of the same press, the sheet is conveyed out of the press.

It is viewed as advantageous that die-cuts which completely cover the positioning geometries, in particular remove the latter as a result, are introduced with the at least one further tool unit.

The previously introduced positioning geometries are thus located in areas which are subsequently die-cut. In particular, these are die-cuts which, in the completed sheet, perform a function, for example for the purpose of fastening and/or fluid guidance, preferably when the completed sheet forms an electrolyser plate or fuel cell plate/bipolar plate.

Especially in this development, provision is preferably made to use the aforementioned further tool unit chronologically after that tool unit with which the aforementioned sub-area is formed. The invention also relates, in addition to the method, to a press having at least one tool unit, in particular which is characterized in that the method can be carried out thereby.

According to the invention, the press comprises at least one tool unit, wherein this at least one tool unit has an upper and a lower forming die, with the interacting deformation structures of which, in a single stroke of the tool unit, it is possible to introduce at least one pattern unit of a sub-area from a deformation pattern to be formed in a sheet, which deformation pattern has a plurality of identical pattern units lying beside one another with a pattern spacing in at least one pattern direction, and the tool unit is configured to shape the sub-area gradually with a plurality of strokes until it has been completed.

Provision is preferably made that a large number of pattern units of the sub-area can be introduced in a single stroke by using the interacting deformation structures.

This is understood in such a way that, according to the invention, it is only a subset of all the pattern units that are formed simultaneously in a single stroke, rather than all the pattern units.

Preferably, provision is made for the press, in particular its tool unit, to have a conveying device by means of which the sheet can be moved onward within the tool unit between successive strokes, in particular can be moved onward by at least one pattern spacing, preferably by a multiple of the pattern spacing.

A possible embodiment can provide for the same press to have at least one further tool unit in addition to the aforementioned tool unit, in particular only exactly one single further tool unit, with which it is possible to form pattern components of the deformation pattern and/or introduce die-cuts into the sheet which are not part of the sub-area, in particular which are arranged on the outside around the latter. Preferably, by using the single further tool unit, the deformation pattern in the sheet, or the sheet as a whole, in particular an electrolyser plate or fuel cell plate, can be completed, preferably with a single stroke. In this case, the at least two tool units form progressive dies of the same press, between which the sheet can be moved onward within the press.

Another embodiment can also provide that, in the press, the tool unit for forming the pattern units of the sub-area can be replaced by the further tool unit with which pattern components which are not part of the sub-area, in particular are arranged around the latter, can be formed in the sheet.

A press, preferably for producing electrolyser plates or fuel cell plates, can also have a plurality of/at least two tool units in a possible embodiment, wherein by using each such tool unit, a respective other sub-area which is composed of identical pattern units is or at least can be formed.

In a development, such a press can likewise have a further tool unit, which shapes and/or die-cuts all the remaining components of the sheet, in particular the electrolyser plate or fuel cell plate.

The invention will be described by using the figures for a preferred exemplary embodiment during the production of fuel cell plates or electrolyser plates.

The following are brief descriptions of the drawings:

FIGS. 1A, 1B, 1C illustrate the interacting components of a tool unit during a first initial stroke;

FIGS. 2A, 2B, 2C show the same situation for a following second stroke of the tool unit after the sheet has been moved onward in the conveying direction;

FIGS. 3A-3C, 4A-4C, and 5A-5C show the repetition of the strokes and the associated positioning of the sheet with positioning geometry on a pin and also the introduction of a respective new positioning geometry by means of a hole punch with each stroke;

FIG. 6 shows the end result of the deformation with the tool unit after shaping of a sub-area of the deformation pattern has been built up gradually with a predetermined number of strokes;

FIGS. 7 and 8 show the product in perspective overview and in detail;

FIG. 9 shows a press according to the invention for carrying out the method, symbolically in an overview; and

FIG. 10 illustrates an embodiment in which the tool unit is used first in the press, the sheets fed to the press being firstly shaped only by the tool unit, i.e. the sub-area is shaped gradually.

FIGS. 7 and 8 discussed above show in a perspective overview and in detail the product produced from a flat sheet 1, in this case an electrolyser plate or bipolar plate or fuel cell plate, in particular from which an electrolyser or a fuel cell can be assembled by being stacked with other plates and elements.

The completely produced sheet 1 here has a deformation pattern, in particular also still further machining in addition thereto, for example die-cuts and edge-cut areas. In particular, this applies to all the sheets 1 produced in accordance with the invention, even outside the preferred application during the production of electrolyser plates or bipolar plates/fuel cell plates. The deformation pattern in all embodiments of the invention is provided by all the elevations and/or depressions relative to the plane of the originally not yet deformed sheet 1. It is produced as a result of deformation machining of the sheet 1, for example by deep-drawing and/or embossing.

Such elevations and/or depressions of the deformation pattern achieve different functions in the shaped sheet 1. In the preferred application they can, for example, form supporting structures via which adjacent sheets 1/electrolyser plates/bipolar plates are supported on one another or on other elements of a stack. They can, for example, also form sealing areas, in particular at the edge of the deformed and preferably cut sheet 1. A particularly significant, in particular enlarged-area, region in the deformation pattern is formed here by elevations and/or depressions which form the so-called flow field of the electrolyser plate or bipolar plate/fuel cell plate or of the sheet 1.

The flow field in this illustrated embodiment comprises a large number of elongated channels 6, which are all formed identically and which are located equidistantly beside one another at right angles to the longitudinal extension direction thereof. In other embodiments different to that shown, the flow field can also have another geometry. Even in the preferred application to electrolyser plates or fuel cell plates/bipolar plates, the invention is not restricted to the flow field actually illustrated. In particular, a flow field can also have other channel courses and/or channel portions but, according to the invention, has a periodicity of a pattern unit in the flow field.

This shows that the entire deformation pattern which is to be introduced into the sheet 1 by a press P, in particular by the at least one tool unit of the latter, has a sub-area which, in this preferred application, forms the flow field, which is distinguished by the fact that a pattern unit 6.1 is arranged therein repeatedly lying beside one another in at least one pattern direction 6.2 (here, e.g. exactly one single pattern direction), wherein the pattern units 6.1 lying beside one another all have the same pattern spacing 6.3. These relationships are illustrated by the detailed view of FIG. 8. The pattern in the sub-area therefore has a rapport or a periodicity which corresponds to the pattern spacing 6.3. The smallest pattern unit 6.1 of the sub-area in this case of the electrolyser plate or bipolar plate is a single channel 6. The pattern spacing 6.3 is the spacing between two adjacent channels 6 or between two pattern units 6.1.

Because of the large number of elevations and/or depressions which are to be produced in the largest-area part of the sheet 1, such a flow field cannot be produced or only with an economically unacceptable outlay by means of a single stroke with a tool unit of a press P, since this would have to be very strongly dimensioned for this purpose.

The invention is aimed at producing such a sub-area of an overall deformation pattern which can be broken down into identical pattern units 6.1 many times repeatedly in one and the same tool unit W1 and gradually with identically repeating strokes and always with the same pair of two forming dies 2/3 located opposite each other and moving in the stroke direction, between which the sheet 1 is moved onward in a conveying direction which corresponds to the pattern direction 6.2. The onward movement, e.g. by using a conveying device acting on the sheet, is carried out in a state in which the forming dies 2, 3 are at a distance from each other and form a gap between them. The pattern direction 6.2 is the direction in which the pattern units 6.1 are arranged lying beside one another. Here, the pattern direction 6.2 is at right angles to the longitudinal extension direction of the channels 6 and/or parallel to the longitudinal extension direction of the sheet 1.

FIGS. 1A, 1B, 1C illustrate the interacting components of a tool unit W1 during a first initial stroke, after which a sheet 1 to be shaped, preferably a sheet 1 that has not yet been deformed until then, was moved into this tool unit W1 in a conveying direction which corresponds to the pattern direction 6.2, in particular by a conveying device acting on the sheet 1.

FIG. 1A shows a horizontal section of a tool unit W1 of a press P with a view through of further elements in other planes parallel to the section plane of the sheet 1 lying therein, e.g. in an open state of the tool unit W1, in which the forming dies 2 and 3 are at a distance, so that the sheet 1 can be moved between the forming dies 2 and 3.

By way of example, a conveying device F, which preferably acts on the sheet 1 on both sides of the same in order to move it, is illustrated dashed in FIG. 1A. The exemplary illustration of the conveying device F chosen in FIG. 1A does not restrict the invention. Conveyance of the sheet 1 can also be achieved by other arrangements of a conveying device F.

For the open state, FIG. 1B shows the section A-A and the section B-B of FIG. 1A with magnified details. FIG. 1C shows the section A-A and the section B-B from FIG. 1A with magnified details for the closed state, in which therefore the forming dies 2 and 3 have been moved toward each other in order to transfer the deformation structure thereof into the sheet 1. The section A-A shows a section through the forming dies 2, 3, preferably centrally, and the section B-B shows a region which, at right angles to the conveying direction, is located laterally offset beside the forming dies 2/3.

The upper forming die 2 and the lower forming die 3 have deformation structures corresponding to one another (in particular negative relative to one another), with which a large number N of pattern units 6.1, here therefore, for example, channels 6, can be formed simultaneously in the sheet 1 with one stroke. The channels 6 are open in a direction at right angles to the sheet plane. This large number N of pattern units 6.1 which can be formed with the forming dies 2, 3 simultaneously in the sheet 1 in one stroke is smaller than the total number of all the pattern units 6.1 located in the sub-area of the deformation pattern, here the flow field. In this example, 14 pattern units 6.1 can be formed at the same time. This number is not restrictive for the invention and can in principle assume any desired value, in particular one which is smaller than the total number of the pattern units 6.1 in the sub-area and preferably is greater than 1.

The tool unit W1 has, besides the forming dies 2, 3 which can be moved toward and away from each other in the stroke direction, bolts 7, with which the sheet 1 can be fixed in its position in the tool unit W1 as it is deformed. Such bolts 7 can preferably be arranged around the forming dies 2, 3.

Laterally offset in a direction at right angles to the conveying direction 6.2 beside the forming dies 2, 3, in particular thus also beside the pattern to be introduced in the sub-area, a hole punch 5 and a pin as a positioning element 4 are provided as an element for introducing a positioning geometry. The hole punch 5 and positioning element 4 preferably form further tools of the total unit W1 in addition to the forming dies 2, 3.

In the first stroke of the tool unit W1, the pin 4 cannot yet move into a hole punched out by the hole punch 5 and perform a positioning as a result. On the other hand, during the initial movement into the tool unit W1, the sheet 1 can be moved in as far as the pin 4, e.g. until contact with the pin 4. Preferably, during the initial stroke, the positioning of the pattern units 6.1 to be introduced/to be formed is not critical, since there is no reference in the sheet 1 with which this first deformation must be aligned. Instead, the interaction of pin 4 with the positioning geometry 5.1 die-cut by the hole punch 5 leads to subsequent deformations of pattern units 6.1 being aligned with the previously formed pattern units 6.1, as will be described below.

In the lower detailed illustration of FIG. 1B, the arrangement of the not yet shaped sheet 1 between the forming dies 2, 3 is shown, wherein the upper detailed illustration shows that the sheet 1 has been moved as far as the pin 4. In this position of the sheet 1, a first stroke is carried out with the tool unit W1, i.e. the sheet 1 is clamped by the bolt 7 and the forming dies 2, 3 are moved toward each other, as a result of which their deformation structure is transferred into the sheet and therefore a number N (preferably N>1) of pattern units 6.1 is formed simultaneously; here, in this example, 14 pattern units 6.1 are formed.

The closed position of the tool unit W1 is shown by FIG. 1C. With the stroke for producing or forming the N pattern units 6.1, which is a subset of all the pattern units 6.1 of the sub-area, at the same time a positioning hole is also introduced into the sheet 1 as a positioning geometry 5.1, laterally offset beside the deformation in the sheet 1.

FIGS. 2A, 2B, 2C show the same situation for a following second stroke of the tool unit W1 after the sheet 1 has been moved onward in the conveying direction 6.2, which corresponds to the pattern direction, following the performance of the first stroke. In this way, an already shaped area is moved at least partly in the conveying direction beside the forming dies 2, 3.

In particular, the lower detailed illustration of FIG. 2B shows, with the tool unit W1 open, that as a result of the onward movement of the sheet 1, the previously created deformation is not moved completely beside the forming dies 2, 3, so that after a stroke of the tool unit W1, as a result of the onward transport of the sheet, an area of the shaped pattern produced in the previous stroke and trailing in the conveying direction is brought to overlap with the deformation structures of the upper and lower forming die.

Furthermore, the upper detailed illustration shows that the pin 4 overlaps the die-cut positioning geometry 5.1 following the onward transport of the sheet 1.

Starting from the second stroke and for each further stroke, it is thus true that as the tool unit W1 is closed during the stroke, as FIG. 2C shows, the tapered pin 4 moves into the positioning geometry 5.1; in this way the sheet 1 is positioned, in particular still before the complete closure of the forming dies 2, 3, preferably because the positioning geometry 5.1 is centred around the tapering free end of the pin 4.

In addition to the existing overlap between the deformation structure of the forming dies 2, 3 with a sub-area trailing in the conveying direction of the deformation of the N pattern units produced in the preceding stroke, very high relative positioning accuracy of the deformation added by the stroke relative to the previous deformation is achieved. It should be pointed out that the overlap shown in the figures is not absolutely necessary, since adequate positioning is also already achieved by the interaction of the pin 4 with the positioning geometry 5.1.

FIG. 2B makes it clear that, in this example, an overlap of the deformation structure of the forming dies 2, 3 takes place with some, here in particular 4, pattern units of the previous deformation. The sheet 1 is thus moved by M pattern units after a stroke, where M is smaller than the number N of pattern units which were introduced/formed or at least which can be introduced/formed in the previous stroke. In the example shown, the values are N=14 and M=10,so that the result is an exemplary overlap of N-M=4 pattern units.

With the following, second stroke, N (14) pattern units are thus again formed, of which M (10) pattern units are newly formed and N-M (4) pattern units, namely the pattern units 6.1 lying in the overlap, are shaped a second time. The distance between the pin 4 and the punch 5 for introducing the positioning geometry 5.1 is defined as a function of the movement width of the sheet 1 between two strokes. This distance is M×pattern spacing here.

As a result of the functionality described, a number N of pattern units 6.1 is formed in the sheet 1 with the first stroke, wherein, after an onward movement of the sheet by M pattern units, with M<N, that is to say with an existing overlap of N-M pattern units, with each following stroke the pattern formed in the sheet 1 is supplemented by M pattern units until, in the last stroke, the forming of the sub-area of the deformation pattern has been completed.

A predetermined total number of pattern units 6.1 to be formed in a sub-area of a deformation pattern can thus always be divided up to a whole number of strokes by the number of pattern units 6.1 that can be formed with a pair of forming dies 2, 3 and a selected overlap. The overlap thus serves only to supplement an increase in precision and can primarily be used to subdivide the total number of pattern units to a plurality of strokes in an expedient way.

The following FIGS. 3A-3C, 4A-4C and 5A-5C show the repetition of the strokes and the associated positioning of the sheet 1 with the positioning geometry 5.1 on the pin 4, and also the introduction of a respective new positioning geometry 5.1 by means of the hole punch 5 with each stroke.

FIG. 6 shows the end result of the deformation with the tool unit W1 after the shaping of the sub-area T of the deformation pattern has been built up gradually with a predetermined number of strokes. According to FIG. 6, the flow field made of the channels 6 is thus completed, the flow field being surrounded laterally by positioning geometries 5.1 created hereby.

By using at least one further tool unit W2, remaining parts of the deformation pattern, in particular deep-drawn areas or embossings, are now produced around the previously shaped sub-area T. In addition, by using the at least one further tool unit W2, preferably with exactly one single further tool unit W2, die-cuts 8 and/or edge cuts 9 and/or supporting geometries 10 and/or sealing channels 11 can also be created on the sheet 1 with a single stroke.

The arrangement of at least some of the die-cuts 8, which preferably serve as a passage for fluids in an electrolyser or a fuel cell, is such that the previously introduced positioning geometries 5.1 are removed again by these die-cuts 8.

FIG. 9 shows a press P according to the invention for carrying out the method, symbolically in an overview.

This comprises at least one first tool unit W1 in which, by means of a number of repeating strokes with the same pair of two forming dies, a sub-area of the deformation pattern which has pattern units 6.1 repeatedly lying beside one another is introduced or formed in the sheet 1. After the multiple strokes for completing the sub-area, the sheet 1 is transported from the first tool unit W1 into the second tool unit W2 of the press. The second tool unit W2 is here part of the same press P which also comprises the first tool unit W1.

In the tool unit W2, which takes over the iteratively shaped sheet 1 from the tool unit W1, the deformation pattern of the sheet 1 is completed, i.e. all the deformations which are provided in addition to the sub-area are made, preferably with a single further stroke. In addition, further die-cuts or cuts on the sheet can be performed in the same stroke. However, the invention can also provide for distributing the further machining of the sheet 1 after the tool unit W1 to a plurality of tool units W2, e.g. performing the remaining deformations with a further tool unit W2 and carrying out die-cuts and/or edge cuts with yet a further tool unit W2.

The tool units W1 and W2 can alternatively also be operated in different presses or chronologically one after another by means of exchanging them in the same press.

FIG. 10 illustrates an embodiment in which the tool unit W1 is used first in the press P. The sheets 1 fed to the press P are here firstly shaped only by the tool unit W1, i.e. the sub-area is shaped gradually, as provided by the invention. The sheets 1 shaped in this way are fed into a buffer 12.

Following the shaping of a predetermined number of sheets 1, in the press P the tool unit W1 is replaced by the tool unit W2, in particular with which those pattern components which are not a part of the produced sub-area T can be formed in the sheet 1. Following the replacement, the previously shaped sheets 1 are removed from the buffer 12 and fed to the press P again, in order then to shape these with the tool unit W2, in particular to complete them.