Rolling machine and method for hollow embossing and cutting rolls

Abstract

The invention relates to a rolling machine and a method for hollow embossing and cutting rolling, with at least one pair of rollers comprising two rolling tools, which defines a rolling gap between them, wherein one of the rolling tools initially has an embossing and cutting contour in order to enable embossing and cutting of workpieces from a strip-shaped starting material as they pass through the rolling gap.

Description

[0001] The invention relates to a rolling machine for hollow embossing and cutting rolling and a method therefor. STATE OF THE ART

[0002] To achieve high-speed production, components and workpieces in the paper and packaging industries are manufactured using a roll-to-roll stamping process. Similar processes are also being developed for the production of bipolar half-plates for electrolyzers and fuel cells. These generally involve cold sheet forming processes, specifically longitudinal rolling processes.

[0003] According to the state of the art, the rolled stock produced in the hollow stamping process is separated or cut from the strip in a second process step. This cutting process can be carried out either by a cutting device with a linear cutting motion, such as a press, or by a roll cutting process.

[0004] With the current state of the art, aligning the embossing contour and the cutting contour of the machines is very complex. Due to the spatial separation of the embossing and cutting machines, an unacceptable misalignment of the embossing and cutting contours on the workpiece often occurs. The waste rate of unusable workpieces is correspondingly high.

[0005] WO 00 / 53355 A1 discloses a method and apparatus for producing plate parts for a heat exchanger. A plate material in the form of a continuous web is guided between two rollers, formed there, and simultaneously cut into a final shape during forming. The outer edges of the plate parts and the outer edges of the internal recesses to be formed in the plate parts are each flat surfaces, allowing them to be easily cut.

[0006] DE 43 19 300 A1 discloses a method for producing half rails with punched-out tabs. In this method, a sheet metal material passes between two rollers of a roller punch, each equipped with male and female tools, to produce half rails with tabs featuring point-shaped formations, as well as holes outside the tabs. The roller punch produces longitudinal tabs in a flat profile base of the sheet metal profile. These tabs are defined by a U-shaped cutting line and a stamping line. For this purpose, cooperating longitudinal cutting edges are provided in the male and female dies, each connected at one end by an arcuate cutting edge and at the other end by a non-cutting, blunt bending edge.

[0007] DE 10 2022 104 250 A1 discloses a method for rolling thin sheet metal for an electrochemical cell, in which the forming of the sheet metal is described by a rolling mill with two rolls which have a surface structure and are operated synchronously.

[0008] The production of rollers with integrated surface structures is labor- and energy-intensive, requiring extensive work from a raw roller through material removal, for example, through milling, grinding, or similar processes. The production of cut workpieces with complex structures, such as edge cutouts and internal cutouts with simultaneous 3D embossing, has not yet been possible with existing technologies, or at least not cost-effectively.

[0009] Another disadvantage of using separate male and female tools built into the roll surface is that the tolerance in the fit of the joined parts during continuous operation reduces the quality of the produced workpieces too much, making such a machine unsuitable for mass production.

[0010] One object of the invention is to improve the quality of the workpieces and minimize deformations and scrap. A further object is to produce workpieces that are as burr-free as possible, or at least have minimal burrs. Yet another object is to manufacture the rolling machine cost-effectively. DISCLOSURE OF THE INVENTION

[0011] The problem is solved by a rolling machine, in particular a longitudinal rolling machine, for hollow embossing and cutting rolling, with at least one pair of rolls comprising two rolling tools, which define a roll gap between them, wherein one rolling tool is designed as a male die and another rolling tool is designed as a female die, wherein the male die and the female die define the roll gap between them and wherein at least one of the rolling tools has an embossing and cutting contour in order to enable embossing and cutting of workpieces made of a strip-shaped starting material as they pass through the roll gap. It is provided that the roll gap defines a plate plane of the workpieces, wherein the embossing and cutting contour is designed to produce elevations in the workpieces relative to the plate plane, and that at least one cutting contour produces a 3D cut which extends over an elevation.

[0012] It is therefore intended that the embossing and cutting contour is designed to carry out a cut in areas of the workpiece that have been deformed by the embossing.

[0013] A 3D section can be understood in the context of the present disclosure to mean that the section contains at least one section that runs at an angle other than 0, preferably greater than 5°, greater than 20°, or greater than 45°, to the plate plane. The section can therefore be described by a two-dimensional curved curve or by a three-dimensional curved curve in space. A 2D section, on the other hand, is understood to mean that the section runs in the plate plane or parallel to the plate plane. A 2D section within the meaning of the present disclosure therefore describes a one-dimensional or a two-dimensional curve in space.

[0014] The rolling machine advantageously enables the simultaneous embossing and cutting of workpieces through a combined rolling and cutting process for strip-shaped components. The embossing contour and the cutting contour on the workpiece are precisely aligned. The spatial proximity of the embossing and cutting contours on the rolling tools minimizes the offset of the embossing and cutting contours on the workpiece.

[0015] Advantageously, the combination of processes allows the embossing process to serve as a hold-down device for the cutting process, thus preventing undue deformation and minimizing burr formation on the workpiece.

[0016] The strip-shaped components can be made of paper, metals, plastics, or composites, for example. The workpieces can be coffee filters, bipolar half-plates, plastic blister packs, packaging containers, etc.

[0017] The rolling machine can be used to produce plate-shaped workpieces that have deformations with cuts in the plate plane and, for example, form open channels in the plate plane.

[0018] According to one embodiment, it is provided that the elevations are formed substantially or entirely in one direction with respect to the plate plane.

[0019] By "essentially" in one direction is meant that more than 50%, preferably more than 70%, more preferably more than 80%, even more preferably more than 90% of the elevations are on the same side with respect to the plane of the plate, whereby the percentage refers to the mass of the material.

[0020] According to a preferred embodiment, the embossing and cutting contours are formed on both rolling tools. The rolling tools are preferably designed to perform shear cutting, knife cutting, and / or biting cutting. The cutting contour of the respective rolling tool comprises corresponding cutting edges for this purpose.

[0021] One rolling tool is designed as a male die, and the second rolling tool as a female die. The stamping and cutting contours are preferably formed in both the male die and the female die. For this purpose, the male die has raised portions on the rolling surface, and the female die has recesses. The male die and the female die form the rolling gap between them.

[0022] It can be provided that all cutting contours are formed as cutting edges in the male part. Alternatively, it can be provided that all cutting contours are formed as cutting edges in the female part.

[0023] In addition, the cutting contour may also include a (visible) structure on the male or female die which does not represent an edge in the true sense, e.g. a raised portion on the male die which interacts with a cutting edge on a female die or vice versa.

[0024] If a section of a cutting curve lies in the workpiece's plate plane, the corresponding section of the cutting contour is preferably formed exclusively in the male die. In other words, to produce cutting curves at the level of the workpiece's plate plane, the corresponding cutting edges are preferably formed in the male die. This ensures that, in the case of rolls with an integrated surface structure, unnecessary, time-consuming clearance work is not required.

[0025] If a section of a cutting curve lies on a maximum elevation of the workpiece, the corresponding section of the cutting contour is preferably formed exclusively in the die. In other words, to produce cutting curves at the level of elevations of the workpiece, especially maximum elevations of the workpiece, the corresponding cutting edges are preferably formed in the die. In the case of rolls with an integrated surface structure, this avoids complex clearance work.

[0026] In the event that the cutting curve runs in a transition area or at the level of an intermediate elevation, the cutting contour is formed either on the die or on the patrix or, particularly preferably, on both the patrix and the die.

[0027] Advantageously, in the case of 3D cutting curves, the corresponding cutting edges are formed on both the male and female dies.

[0028] Advantageously, in the case of 2D cutting curves, the corresponding cutting edges are formed exclusively on the male or female die.

[0029] Depending on the design of the tools, the embossing and cutting contours or the roll gap can be formed by a surface profile of the rolling tools, e.g., produced by milling, grinding, blasting, laser ablation, electrochemical ablation, or similar processes. Reference may be made to the relevant specialist knowledge.

[0030] Alternatively, the embossing and cutting contour or the roll gap can be formed by functional surfaces on the rolling tools, e.g., by attachments, in particular screwed, wedged, and / or welded components.

[0031] The rolling tools can each be monolithic or consist of two or more partial bodies. Particularly preferably, at least one of the rolling tools, preferably both rolling tools, are monolithic. In the understanding of the present disclosure, the embossing and cutting contour is formed by the surface profile of the rolling tools.

[0032] The invention also includes a rolling tool which is suitable for use in the machine described above.

[0033] In a method according to the invention for hollow embossing and cutting rolls, it is provided that workpieces made of a strip-shaped starting material are cut, in particular 2D and 3D cut, and simultaneously embossed as they pass through a roll gap on a pair of rolls comprising two rolling tools by means of knife cutting or bite cutting, preferably knife cutting. Knife cutting is particularly advantageous in the area of ​​the plate plane and in the area of ​​maximum elevations, since it minimizes the clearance waste on the rolling bodies, especially in the case of rolls with an integrated surface structure.

[0034] The method is preferably carried out by one of the previously described machines. The features disclosed with respect to the device are therefore also to be considered disclosed with respect to the method, and vice versa.

[0035] This is preferably a process from the field of cold sheet forming, preferably a longitudinal rolling process.

[0036] In the method according to the invention, at least one cut preferably runs as a 3D cutting curve through an embossed portion of the material. BRIEF DESCRIPTION OF THE CHARACTERS

[0037] The invention is described below with reference to the figures. They show: Figure 1 shows a perspective view of a section of a workpiece as a result of carrying out a method according to the invention, Figure 2 shows a perspective view of a further section of a workpiece as a result of carrying out a method according to the invention, Figure 3 shows a section of the area B from Figure 1, Figure 4 shows a section through a pair of rollers according to one embodiment of the invention, Figure 5 shows a section through a pair of rollers according to a further embodiment of the invention, Figure 6 shows a section through a rolling surface of a die for producing the area C from Figure 1 , Figure 7 a section of a rolling surface of a male part corresponding area D in Figure 6 , Figure 8 a section of a male part for the production of a Figure 1 illustrated area and Figures 9A to 9C show various embodiments of cutting means. EMBODIMENTS OF THE INVENTION

[0038] The invention is explained below with reference to the figures. These figures include a variety of embodiments that are not explicitly described but are familiar to those skilled in the art based on their specialist knowledge.

[0039] Figure 1shows a perspective view of a section of a workpiece 10 which can be produced with the aid of the method according to the invention. The workpiece 10 is designed here, for example but not restrictively for the invention, as a bipolar plate 12 with a flow field 14 in which reactants of a fuel cell are brought together, for example H 2 and O 2 to form water with the release of energy. The bipolar plate 12 therefore contains a multiplicity of material channels 16 in order to guide the reactants involved, but also, for example, coolant, through the bipolar plate. In the illustrated embodiment of the bipolar plate, the material channels 16 have material inlets 18 which are not located in an edge region of the workpiece 10, but in the interior of the workpiece 10 in the region of internal cutouts 28, which are also referred to as ports or media ports 17.

[0040] In Figure 2is another excerpt from the Figure 1 shown workpiece 10, here with a further internal cutout 28, which, however, does not provide the function of a port, but rather an alignment or positioning aid 19 when stacking many bipolar plates 12 on top of one another.

[0041] However, the embodiment of the workpiece 10 as a bipolar plate 12 is not limiting for the invention. It can be used with a variety of different types of workpieces 10. The workpieces 10 can be made of, for example, paper, metals, plastics, or other composite materials.

[0042] The workpieces 10 produced according to the invention have in common that they are initially available as strip goods and are then separated into workpieces 10 at a high cycle rate as part of a cutting process.

[0043] In the preferred application, the workpiece 10 is characterized by an edge cutout 30, one or more internal cutouts 28, one or more 2D cutting curves 32 and one or more 3D cutting curves 34.

[0044] As in Fig. 2 and 3 In the case of the embodiment shown as a bipolar plate 12, in particular the alignment or positioning aids 19 can be contoured by 2D cutting curves 32 and the media ports 17 by 3D cutting curves 34.

[0045] The two-dimensionality of the direction refers to a plate plane 20, which can typically be identified with the surface of the unrolled plate. The 2D cutting curve 32 within the meaning of the present invention runs in the plate plane 20. The 3D cutting curve 34 also runs in the plate plane 20, but also perpendicular to it.

[0046] In Figure 1It can be clearly seen that the workpiece 10 has elevations 22, whereby the present invention distinguishes between maximum elevations 24 and intermediate elevations 26. The maximum elevation 24 corresponds to the greatest distance from the plate plane 20, which was achieved by embossing, deep drawing or cold forming, and flow of the material. In the context of the present invention, the intermediate elevation 26 does not refer to the transition region 25 between the plate plane 20 and the maximum elevation 24, but rather a flat extension of the workpiece 10 between the maximum elevation 24 and the plate plane 20 for functional purposes.

[0047] The Figure 3In the illustrated embodiment, the 3D section curve 34 extends from the plate plane 20 to the intermediate elevation 26. A transition region 25, which is typically rounded, is provided between the intermediate elevation 26 and the maximum elevation 24. Likewise, a transition region 25 is present between the plate plane 20 and the intermediate elevation 26.

[0048] Such geometries in the workpiece with intermediate elevation 26 and maximum elevation 24 are often necessary within the scope of the flow field design of bipolar plates 12, for example as flange areas for supply lines at the material inlet 18 or as functionally narrowed flow sections in the material channel 16 for nozzle-like turbulences.

[0049] In other applications, the 3D section curve 34 does not have to be limited to the area between the plate plane 20 and the intermediate elevation 26, but can also run in the area from the plate plane 20 to the maximum elevation 24 or similar.

[0050] The internal cutouts 28 can have any desired complexity and extend over one or more planes, in particular over the plate plane 20, the intermediate elevations 26, and / or the maximum elevations 24. One or more internal cutouts 28 can be present.

[0051] According to the hollow stamping and cutting rolling process of the present invention, the workpiece 10 is preferably separated and thus generally circumferentially surrounded by the edge cutout 30, but this is not limiting for the invention.

[0052] The workpiece 10, which is in Figure 1 - 3shown, is manufactured using a combined hollow embossing and cutting rolling process. Figure 4 is a section through a pair of rollers with a male die 40 and a female die 50. The Figure 4 The section of the roller pair shown is suitable for Figure 1 shown section A - A.

[0053] The male part 40 has a three-dimensional rolling surface 42. In the illustrated area, the rolling surface 42 comprises a cutting edge 48 in order to cut the inner cutout 28 out of Figure 1 to cut out. During radial advance of the male die 40 toward the female die 50, the cutting edge 48 strikes the opposite rolling surface 52 of the female die 50, which has no counter elevation at this point.

[0054] The roll gap 36 is adapted to the thickness of the workpiece 10 to be produced, but at the level of the cutting edge 48 it is reduced to the cutting gap, preferably to zero.

[0055] The rolling surface 42 of the male die 40 further comprises elevations 46 which extend radially further away from the main axis of the rolling roller than a clearance base 44 which defines the position of the plate plane 20 in the workpiece 10.

[0056] Spatially opposite the elevation 46 on the male die 40, there is a corresponding depression 56 in the rolling surface 52 of the female die 50. The elevation 46 and the depression 56 interact in such a way that a continuous sheet of material experiences a hollow embossing in this area, see line A - A in Fig. 1 .

[0057] Figure 5shows a situation in which the male die 40 and the female die 50 are designed to cut the workpiece 10 at the level of a protrusion 22. For this purpose, the female die 50 has a cutting edge 58 on its rolling surface 52 in the area of ​​the depression 56. The male die 40 has the corresponding protrusion 46 at the corresponding location but no cutting edge of its own. The protrusion 22 to be created in the workpiece 10 is the protrusion 22 shown in Figure 5 illustrated embodiment preferably by a maximum elevation 24.

[0058] The design variants shown ensure that unnecessary, time-consuming clearance work is not required. The clearance work can be performed, for example, by milling, but can also be performed by laser ablation, erosion, or electrochemical ablation. Figure 4 and Figure 5In the variant shown, the cutting edge 48 of the male part 40 and the cutting edge 58 of the female part 50 are each formed on the relief base 44 of the male part and 54 of the female part, respectively. In the context of the present invention, the term relief base refers to the minimum rolling roll thickness, i.e., the deepest relief in the rolling roll. If, for example, the male part 40 were to have a cutting edge 48 in the area of ​​its elevation 46, the pre-relief diameter of the male part 40 would be defined by the tip of the cutting edge 48. The term pre-relief diameter refers to the shape of the female part 50 and male part 40 before the relief work. In the areas of the maximum elevations 24 of the workpiece 10, the cutting edge 58 is therefore preferably provided on the female part 50.Conversely, if the die 50 were to have a cutting edge 58 at the level of the plate plane 20, the pre-cut diameter of the die 50 would be determined by the tip of the cutting edge 58 of the die at that location. Therefore, the die 50 would have to be cut out over a large area outside of this cutting edge, which would require additional effort.

[0059] Figure 6 shows the rolling surface 52 of the die 50 in the area C in Figure 1 Here, the workpiece 10 is to be cut in a 3D section both at the level of the plate plane 20 and through one of the elevations 22. In the elevation in area C (see Fig. 1 ), for example, there is a maximum elevation of 24.

[0060] Figure 6shows the die 50 from its underside. 56 denotes depressions in the die, which form the elevations 22 in the workpiece. The cutting edge 58 in the die 50 runs exclusively in the area of ​​the depression 56. As with reference to Figure 4 and Figure 5 As already explained in principle, the cutting edge 58 of the die 50 is provided only in the area of ​​the recess 56. However, the recess 56 also extends over the cutting edge 58 of the die and forms a stamping waste 64 here. The stamping waste 64 serves the purpose of reducing internal material stresses and preventing the formation of wrinkles in the workpiece 10.

[0061] In the transition area of ​​the depression 56 to the pre-relief diameter, marked with reference number 60, the cutting edge 58 merges into the male part 40, which is also related to the Figure 7 is shown.

[0062] Figure 7 shows the male part 40 in the area marked D in Figure 6 , which is in Figure 6 shown die 50, the inner cutout 28 from the workpiece 10 in the area C in Figure 1 to cut out.

[0063] The male part 40 here has the corresponding elevation 46, which corresponds to the depression 56 of the female part 50, and a corresponding cutting edge 48, which in combination with the cutting edge 58 of the female part 50 produces the 3D cutting curve 32.

[0064] Just as with the die 50, the elevation 46 is continued in the cut-out area and forms a corresponding embossed waste 64, as already explained with reference to Figure 6 explained.

[0065] Figure 8 shows the male part 40 in the area of Figure 1 the inner section 28 shown on the right. The 3D section curve 34 (see Fig. 3 ) runs over the plate level 20 and the intermediate elevation 26.

[0066] The cutting edge 48 on the male part 40 forms a closed curve at this point. As with reference to Figures 4 and 5 As explained, the section of the cutting edge 48 in the area of ​​the plate plane 20 is technically advantageous in order to minimize clearance work, e.g., milling work. Furthermore, the male part 40 has elevations 46 here, namely maximum elevations 46b and intermediate elevations 46a.

[0067] In the transition region 62, cutting can be implemented in different ways. For example, in this region, the cutting edge 48 can be formed on both the male part 40 and the female part 50. The illustrated embodiment of the closed cutting curve 48 on the male part 40 for forming the 3D cutting curve 34 is therefore only one of several possibilities.

[0068] Figures 9A to 9C show different embodiments of cutting processes on workpieces 10.

[0069] In Figure 9AShear cutting is shown, in which two shearing edges 70 are offset parallel and moved towards each other without a transverse gap in order to shear the workpiece 10. This type of cutting is particularly advantageous in the transition areas 60 or in the areas of cutting curves on intermediate elevations 26. If the increased clearance costs are accepted, shear cutting can be carried out in Figure 9A but can be implemented at any location by aligning and designing the corresponding cutting edges 48 and 58 on the male die 40 and female die 50, respectively, to each other.

[0070] The advantage of shear cutting is that material bulges 76 (see Fig. 9B and 9C ) are deflected in one direction each due to the oblique shear edges 70.

[0071] With reference to the Figures 4 to 8 was that in Figure 9BThe knife edges shown have already been described. Here, a knife edge 72 meets a substantially flat support 74 to cut the workpiece 10. Knife cutting is particularly advantageous in the area of ​​the plate plane 20 and in the area of ​​the maximum elevations 24, since, as already explained, it minimizes the clearance waste on the rolling elements. A disadvantage is the material projections 76 caused by the displacement of the material at the knife edge 72; however, this method operates completely burr-free. In the context of the present disclosure, the term "wedge cutting" can also be used instead of the term "knife cutting," since the knife edge 72 is understood to be a wedge-shaped cutting tool.

[0072] Figure 9CFinally, the figure shows bite cutting, in which two knife edges 72 are moved toward each other and cut the workpiece 10 between them. Here, too, material bulges occur on all sides, although these are less pronounced than with knife cutting. This process also operates without burrs. Due to the precision achievable today in the feed of the two rolling tools, bite cutting can be carried out successfully.

[0073] In the case of bipolar plates, where two workpieces 10 are placed against each other to define a flow field 14 between them, the material projection 76 is arranged in the direction of the inside in order to produce a clean cutting result on the outside.

Claims

1. Rolling machine for hollow embossing and cutting rolling, with at least one pair of rolls comprising two rolling tools, which define a rolling gap (36) between them, wherein one rolling tool is designed as a male part (40) and another rolling tool is designed as a female part (50), wherein the male part (40) and the female part (50) define the rolling gap (36) between them and at least one of the rolling tools has an embossing and cutting contour in order to enable embossing and cutting of workpieces (10) made of a strip-shaped starting material as they pass through the rolling gap (36), and wherein the rolling gap (36) defines a plate plane (20) of the workpieces (10), characterized in that the embossing and cutting contour is designed to produce elevations (22) in the workpieces (10) relative to the plate plane (20) and to produce at least one 3D cut which extends over at least one elevation (22).

2. Rolling machine according to claim 1, characterized in thatthe elevations (22) are formed substantially or entirely in one direction with respect to the plate plane (20).

3. Rolling machine according to one of the preceding claims, characterized in that the embossing and cutting contour is formed on both rolling tools.

4. Rolling machine according to claim 3, characterized in that for producing cutting curves (32, 34) at the level of the plate plane (20) of the workpiece (10), the corresponding cutting edges (48) are preferably formed exclusively in the male part (40).

5. Rolling machine according to claim 3 or 4, characterized in that for producing cutting curves (32, 34) at the level of a protrusion (22) of the workpiece (10), in particular the maximum protrusion (24) of the workpiece (10), the corresponding cutting edges (58) are preferably formed exclusively in the die (50).

6. Rolling machine according to one of the preceding claims 3 to 5, characterized in thatfor producing cutting curves (32, 34) in transition areas (25) or at the level of intermediate elevations (26) of the workpiece (10), the corresponding cutting edges (48, 58) are formed on both the male die (40) and the female die (50).

7. Rolling machine according to one of the preceding claims 3 to 6, characterized in that in the case of 3D cutting curves (34), the corresponding cutting edges (48, 58) are formed on both the male die (40) and the female die (50).

8. Rolling machine according to one of the preceding claims 3 to 7, characterized in that in the case of 2D cutting curves (32), the corresponding cutting edges (48, 58) are formed exclusively on the male die (40) or on the female die (50).

9. Rolling machine according to one of the preceding claims, characterized in that the roll gap (36) is formed by a surface profile on rolling surfaces (42, 52) of the rolling tools or by functional surfaces on the rolling tools.

10. Rolling machine according to one of the preceding claims, characterized in that at least one, preferably both rolling tools are monolithic.

11. Rolling machine according to one of the preceding claims, characterized in that the rolling tools are designed to perform shear cutting, knife cutting and / or biting cutting.

12. Rolling tool adapted for use in a rolling machine according to any one of the preceding claims.

13. A method for hollow embossing and cutting rolling, wherein workpieces made of a strip-shaped starting material are cut and embossed at the same time by means of knife cutting or biting cutting, preferably knife cutting, when passing through a roll gap (36) on a pair of rolls comprising two rolling tools.

14. Method according to claim 13, characterized in that at least one cut runs as a 3D cutting curve (34) through an embossing.

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