WO2022136123A1

WO2022136123A1 - Method and device for the high-pressure shaping of workpieces

Info

Publication number: WO2022136123A1
Application number: PCT/EP2021/086273
Authority: WO
Inventors: Markus Werner
Original assignee: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority date: 2020-12-22
Filing date: 2021-12-16
Publication date: 2022-06-30
Also published as: EP4267322A1; DE102020134557A1

Abstract

The present invention relates to a device for the high-pressure shaping of workpieces (8), in particular for producing heat exchanger plates and bipolar plates. The device comprises a mold having a shaping section (4, 11) and a fluid basin (5), between which the workpiece (8) for high-pressure shaping can be arranged. The device is configured to generate a high-pressure pulse in the fluid basin (5) so that the workpiece (8) is forced through the shaping section (4, 11) by means of the high-pressure pulse. The present invention also relates to a corresponding shaping method.

Description

Process and device for high-pressure forming of workpieces

technical field

The present invention relates to a device and a method for high-pressure forming of workpieces according to the preambles of claims 1 and 8, respectively.

For the production of flat components by means of a non-cutting forming process, presses are usually used in which forming tools are used in order to receive a workpiece blank and then bring it into the desired shape by applying appropriate force. For the economical production of flat components for the mass market, high productivity at low costs is sought. Various processes are used for the forming production of heat exchanger plates and in particular for bipolar plates.

Hollow embossing or rolling leads to high output quantities, but requires compromises in terms of channel design. Cold and hot forming can lead to component distortion after production is complete. Fast processes such as electrohydraulic forming or electromagnetic forming are still being researched for this application.

The process of high-pressure forming has become established, particularly in the area of forming plate-shaped workpieces such as sheet metal, but also for forming other workpieces such as pipes. The semi-finished product is pressed against a forming die within a hydroforming tool using a fluid, in particular water, oils, emulsions or gases, whereby the forming is achieved. The tool is placed in a housing that absorbs the forming forces.

Forming using an active medium (hydroforming, high-pressure sheet metal forming) offers the highest component quality and sophisticated channel structures as well as process robustness, but on the other hand has a supposedly low productivity. However, this is due to the system technology used and not so much to the process. The aim of the present disclosure is to exploit the advantages of high-pressure sheet metal forming through optimal plant and process engineering.

Description of the prior art

Hydroforming tools for sheet metal forming usually consist of an upper tool part, which includes the forming die, and a lower tool part in which a line for applying fluid to the workpiece under high pressure is arranged. Alternatively, the forming die can also be arranged in the lower part of the tool and the line for applying fluid to the workpiece can alternatively also be arranged in the upper part of the tool. For forming, the workpiece, for example a metal sheet, is clamped between the upper tool part and the lower tool part, with the lower tool part resting against the workpiece via a seal. The workpiece is then subjected to the fluid under high pressure, as a result of which the workpiece is evenly pressed against the die.

A forming device according to the preamble of claim 1 is known, for example, from patent specification DE 102013020280 B3. A device for forming a workpiece by means of a free-flowing active medium is disclosed therein. The device comprises a forming tool, which has a die designed to produce a workpiece shape, and a holding tool, which holds a semi-finished product to be formed in a parting plane between the holding tool and the forming tool. By applying an active medium to a semi-finished product held in the parting plane, and with a pressure generating device for pressurizing the active medium, the workpiece is formed in accordance with the forming tool. The mold, the holding tool and the pressure generating device for operation are designed as a press.

However, the device described above also entails some disadvantages: the pressurization of the active medium is carried out by means of displacement by the pressure generating device. This means a complex and time-consuming application of pressure at a low pressure level. In addition, in conventional devices, such as those mentioned above, after the press has been closed and the closing force has been built up, the pressure intensifier is only then actuated, which then compresses and conveys the high-pressure fluid. Depending on the system control, the locking forces and the high pressure can only be controlled at certain time intervals, which delays the forming process. In addition, the opening and closing of hydraulic presses takes a certain amount of time.

The object of the present invention is to solve the problems known from the prior art and to provide a device for the time-saving forming of flat components with high efficiency.

In order to achieve the object defined above, the present invention discloses an apparatus according to claim 1.

The device according to the invention is used for high-pressure forming of workpieces, in particular for the production of heat exchanger plates and bipolar plates, and includes a Mold with a shaping section and a fluid basin, between which the workpiece for high-pressure forming can be arranged. According to the invention, the device is configured to generate a high-pressure pulse in the fluid pool, so that the workpiece is pressed against the shaping section by the high-pressure pulse.

The device according to the invention has the advantage that the workpiece can be subjected to a high-pressure pulse immediately upon or after closing the mold. Due to the possibility of immediate application of the pressure pulse, rapid forming and thus high productivity can be achieved. In addition, the times for filling and emptying the fluid are eliminated if the fluid basin remains full.

Advantageous developments of the invention are the subject matter of the dependent claims.

It can be advantageous if the device has at least one high-pressure fluid reservoir, the high-pressure pulse being generated at least partially or completely by filling the fluid basin with high-pressure fluid from the high-pressure fluid reservoir. When introduced into the fluid basin, the high-pressure fluid from the high-pressure fluid reservoir suddenly causes a pressure increase in the fluid basin or the desired high-pressure impulse. In this so-called “active variant”, the high-pressure impulse is generated by increasing the amount of fluid in the fluid basin, preferably while maintaining the volume of the fluid basin. The high-pressure impulse generated in the fluid basin leads to a targeted deformation of the workpiece by the workpiece being pressed against the shaping section.

It can be useful that the high-pressure pulse is generated at least partially or completely by closing the fluid pool, in particular with the workpiece, and reducing the volume of the fluid pool, in particular with the workpiece, to increase the pressure of the fluid enclosed in the fluid pool. In this so-called “passive variant”, the high-pressure impulse is generated by reducing the volume of the fluid basin, preferably while maintaining the amount of fluid in the fluid basin. The "active variant" and the "passive variant" can also be combined, for example by reducing the volume of the fluid basin and at the same time increasing the amount of fluid in the fluid basin. In the "passive variant", for example, the workpiece penetrates into the fluid basin without fluid being able to escape from the fluid basin. As a result, the fluid pressure in the fluid basin is suddenly increased. The high-pressure pulse generated in this way causes the workpiece to be deformed in a targeted manner by the workpiece being pressed against the shaping section. It can be advantageous if the mold is formed from a lower tool and an upper tool, with the upper tool preferably having the shaping section and the lower tool having the fluid basin. This allows the tools to be individually selected and assembled to create a desired shape. In addition, the shaping section and the fluid basin in the upper and lower tools can be matched to one another, depending on the application.

It can be useful if the high-pressure fluid reservoir can communicate with the fluid pool via a high-pressure channel, the device comprising at least one high-pressure valve for opening and closing the high-pressure channel. Thus, the fluid basin can be charged with high-pressure fluid in a targeted manner via the high-pressure valve. In addition, the high-pressure accumulator and fluid basin can be locally separated from one another via the high-pressure channel in order to achieve a high level of design freedom for the overall device.

It can be helpful if the device includes a transport device in order to transport workpieces into and/or out of the mold, with the transport device preferably being designed as a conveyor belt. In this way, workpieces and formed components can be transported gently on a (conveyor) belt.

It can be useful if the device has at least one low-pressure fluid reservoir which can communicate with the fluid pool via a low-pressure channel in order to fill the fluid pool with low-pressure fluid, the device preferably having at least one low-pressure valve for opening and closing the low-pressure -channel includes. In addition to the high-pressure channel, the low-pressure channel serves as an inlet for the fluid basin, via which the fluid basin can be fed with fluid under low pressure—in particular when it is not pressurized. The low-pressure valve allows the low-pressure channel to be opened and closed before and after the actual forming process.

It may be practical if the mold can be transferred between an open position and a closed position, the device preferably comprising a press, preferably a crank or toggle press, for transferring the mold between the open position and the closed position, the Pressing is particularly preferably mechanically or hydraulically actuated. With these variants, the workpiece can be easily introduced into the mold and removed from it again. High pressure forces can be built up by the pressing plant, which corresponds to the pressure of the high-pressure fluid have to withstand during pressure forming. Mechanically or hydraulically actuated pressing units can be technically implemented easily and effectively.

It can be advantageous if the mold has at least one ventilation opening in order to discharge gas that is displaced during the shaping of the workpiece from the shaping section. This avoids a pressure build-up in the shaping section during high-pressure forming. As a result, the pressure required for high-pressure forming is reduced and the forming result in terms of shape accuracy is improved

In order to achieve the object defined above, the present invention also discloses a manufacturing method according to claim 12. It offers essentially the same advantages as the device according to the invention.

The method according to the invention is used for high-pressure forming of workpieces, in particular using the device according to claim 1. The method comprises a step of arranging a workpiece in a mold with a shaping section and a fluid basin, so that the workpiece is arranged between the shaping section and the fluid basin; and a step of generating a high-pressure pulse in the fluid pool to urge the workpiece against the forming section.

In an advantageous (active) variant, the high-pressure pulse is generated at least partially or completely by filling the fluid basin with high-pressure fluid from a fluid reservoir.

In a further advantageous (passive) variant, the high-pressure pulse is generated at least partially or completely by sealing the fluid basin, in particular with the workpiece, and reducing the volume of the fluid basin, in particular with the workpiece, to increase the pressure of the fluid enclosed in the fluid basin.

It may also be useful if the pool of fluid is overflowed as the workpiece is transported into and/or out of the mold so that the workpiece floats on a film of fluid. This has the advantageous effect that, due to the surface tension or the flow force of the fluid, a formed component can be transported out of the mold by means of the fluid film. Furthermore, an approaching workpiece to be formed can also be transported into the mold on the fluid film. As a result, the workpiece or the formed component can be transported easily and gently.

It can be useful if the shaping section is in the form of a female or male part. The die as a shaping section is particularly suitable for the active variant, in which the high-pressure impulse is achieved by increasing the amount of fluid in the fluid basin,

It can be helpful if the device has a fixing section that can be moved separately from the shaping section and is configured to fix the workpiece in relation to the fluid basin. The patrix as a shaping section is particularly suitable in the passive variant, in which the high-pressure impulse is achieved by reducing the volume of the fluid basin to increase the pressure of the fluid enclosed in the fluid basin.

However, it can also be useful if fluid is supplied to the fluid basin during transport of the workpiece into and/or out of the mold, preferably from a low-pressure fluid reservoir. This provides replenishment of scavenged fluid and ensures a fluid-filled fluid pool.

However, it may also be practical if a pressure in the fluid basin is greater than the ambient pressure when the mold is opened. Thus, due to the pressure gradient, the fluid flows out of the fluid basin when the mold is opened and reinforces the fluid film mentioned above.

It can prove to be practical if the workpiece seals the fluid basin when it is filled with high-pressure fluid. Thus further sealants can be saved.

It can be useful if the volume of high-pressure fluid that is fed to the fluid basin for high-pressure forming of the workpiece, based on the area of the workpiece to be formed, is at most 0.02 cm ³ per cm ² , preferably at most 0.01 cm ³ per cm ² . It can thus be ensured that components such as heat exchanger plates and bipolar plates, which have a complex channel structure with small cross-sectional dimensions, can be produced particularly quickly using the forming technology according to the invention.

It may be helpful if a pressure of the high-pressure fluid is in the range of 200 to 500 MPa, preferably in the range of 300 to 500 MPa, preferably in the range of 400 to 500 MPa. With pressures in the stated pressure ranges, particularly fine structures can be produced by high-pressure forming.

It can be useful if the pressure of the low-pressure fluid is in the range from 1 to 10 MPa, preferably in the range from 2 to 10 MPa, preferably in the range from 5 to 10 MPa. Such pressures can be compared to those required for high pressure forming Compressions can be generated comparatively easily and made available at short notice. This simplifies the implementation of the method according to the invention.

Further preferred developments of the invention result from combinations of the features that are disclosed in the description, the claims and the figures.

terms and definitions

The term “fluid basin” includes a fluid chamber that is exposed to the workpiece to be formed when it is arranged as intended or is closed by the workpiece, so that the pressure of the introduced high-pressure fluid acts on the workpiece and presses it against the shaping section. The shape of the fluid chamber and its arrangement with respect to the workpiece are secondary. The term "fluid basin" is used in the singular to represent a single fluid chamber or multiple fluid chambers. The fluid basin can be located at least in sections below and/or at least in sections above the workpiece and/or at least in sections to the side of the workpiece. The fluid basin preferably has an opening on the upper side, which is closed by the workpiece when the workpiece to be formed is arranged as intended. Ideally, the fluid remains at least largely in the fluid basin when the workpiece is removed from the mold. Ideally, the pool edge of the fluid pool lies in a horizontal plane.

The term "filling" is to be understood in such a way that high-pressure fluid is introduced from the high-pressure fluid reservoir into the fluid pool, so that the pressure of the high-pressure fluid acts on the workpiece and presses it against the shaping section. The fill level of the fluid basin at the beginning of the introduction of the high-pressure fluid from the high-pressure fluid reservoir into the fluid basin is irrelevant. It is preferred that the fluid basin is already partially filled at the beginning of the introduction of the high-pressure fluid from the high-pressure fluid reservoir into the fluid basin. This reduces the amount of high-pressure fluid required for high-pressure forming—and thus the time required to fill the fluid basin. However, it is also possible for the fluid basin to be filled from a completely empty state, in particular when it is used for the first time or when it is put into operation again after maintenance.

Brief description of the figures

Show it:

1 shows a basic sketch of a section through the device according to the first exemplary embodiment of the invention in a state before the forming process. FIG. 2 shows a basic sketch of a section through the device according to FIG. 1 in a state during the forming process.

3 shows a basic sketch of a section through the device according to FIGS. 1 and 2 in a state after the forming process.

4 shows a basic sketch of a section through a device according to the second exemplary embodiment of the invention in a state before the forming process.

FIG. 5 shows a basic sketch of a section through the device according to FIG. 4 in a state during the forming process.

6 shows a basic sketch of a section through the device according to FIGS. 4 and 5 in a state after the forming process.

Detailed description of the preferred embodiments

1 shows a basic sketch of a section through the device for high-pressure forming of flat components according to the first exemplary embodiment of the present invention. The device shown in FIG. 1 represents a press which is arranged on a platen 1 or a press table 1 as the frame of the press. The press essentially consists of a lower tool 2 and an upper tool 3. The lower tool 2 is arranged on the clamping plate 1 and fixed to it if necessary. The upper tool 3 is located above the lower tool 2 and is configured to be placed on the lower tool 2 . The lower tool 2 and the upper tool 3 are arranged in such a way that the underside of the upper tool 3 can be brought together with the upper side of the lower tool 2 .

The press includes a press tool or mechanism that can bring the upper die 3 and the lower die 2 toward each other, compress them, and move them away from each other. 1 shows the press in an open state before the forming process. The press can preferably be closed and opened mechanically or hydraulically, so that the lower tool 2 can be brought together with the upper tool 3 and moved away from one another. Here, a movement of the upper tool 3 in the vertical direction is indicated by the arrows. A vertical movement of the lower die 2 can also be provided for the present press. In addition, a folding mechanism with hinges is conceivable, via which the lower tool 2 and the upper tool 3 are connected so that they can be brought together.

On the side facing the lower tool 2 , the upper tool 3 comprises a shaping section designed as a die 4 . The die 4 is shaped such that it has a negative form of a component to be formed. The die 4 can have a shape contour or just an engraving to produce the component shape. The die 4 runs almost over the entire length of the upper tool 3. The depth of the die 4 corresponds to the depth of the component to be formed. The upper die 3 and the lower die 2 are shaped so as to seal with each other in a compressed state and form a sealed space inside the press.

Before a forming process, a workpiece blank 8 to be formed is inserted between the lower tool 2 and the upper tool 3 and applied to the upper side of the lower tool 2 . The dimensions of the lower and upper tools 2, 3 are selected in such a way that no ends of the workpiece blank 8 protrude beyond the edges of the lower and upper tools 2, 3. Thus, a tightness of the press can be guaranteed. In addition, the dimensions of the die 4 are selected in such a way that the surface of the contour of the die 4 is arranged entirely over the surface of the workpiece blank 8 in a plan view.

The lower tool 2 has a fluid basin 5 on its upper side. The fluid pool 5 is arranged below the die 4 when the lower tool 2 and the upper tool 3 are brought together. The dimensions of the fluid basin 5 are selected in such a way that the workpiece blank 8, which was placed over the fluid basin, completely covers the fluid basin 5. In addition, the fluid pool 5 is shaped in such a way that the surface of the fluid pool 5 of the lower tool 2 encloses the ends of the surface of the mold contour of the die 4 in a plan view. Thus, in a top view, no edges of the mold contour of the die 4 protrude beyond the edges of the fluid basin 5 .

The fluid basin 5 also has a high-pressure fluid connection 6 . The high-pressure fluid connection 6 serves as an inlet for the fluid basin 5, via which the fluid basin 5 can be fed with fluid under high pressure of more than 500 MPa. The high-pressure fluid connection 6 is a high-pressure valve which is connected to a high-pressure hydraulic system with a high-pressure accumulator. Here, the high-pressure hydraulic system is designed in such a way that it has the features of a common rail injection unit. This means that the high-pressure hydraulic system with the high-pressure accumulator (common rail) permanently provides high pressure and can use this to build up pressure through the high-pressure valve if necessary. The high-pressure fluid connection 6 is thus configured in such a way that it can apply a high-pressure impulse to the fluid basin 5 during the forming process when the press is closed, in order to force the workpiece 8 against the forming section and to form it. After the workpiece 8 has been formed, the valve of the high-pressure fluid connection 6 is closed, whereby the Fluid basin 5 is no longer applied with overpressure fluid, but an overpressure in the fluid basin is maintained.

Heat exchanger plates and in particular bipolar plates are to be designed in such a way that they have a large heat transfer surface. This is achieved through a complex channel structure within the heat exchanger plate. Here, the channels have small cross-sectional dimensions. The present method and the present device are advantageous for such components, since these components have a very small forming volume in relation to the base area. When applying such channels in a forming process, a small but targeted pressure impulse is usually necessary to form a workpiece into the desired shape. For example, in the case of a heat exchanger plate with an area of 200×500 mm ² , only 10 to 20 cm ³ of fluid is required for shaping, depending on the channel depth. Based on the area of the workpiece 8 to be formed, the area-specific volume of the high-pressure fluid that is supplied to the fluid basin 5 for high-pressure forming of the workpiece 8 is therefore at most 0.02 cm ³ per cm ² , preferably at most 0.01 cm ³ per cm ² . Such targeted high-pressure pulses can be generated easily and quickly with the device according to the invention and applied to the workpiece in an uncomplicated manner.

The fluid basin 5 also has a low-pressure fluid connection 7 . The low-pressure fluid connection 7 serves as an inlet for the fluid basin 5, via which the fluid basin 5 can be fed with fluid at a low pressure of up to 10 MPa. In this case, the low-pressure fluid connection 7 is a low-pressure valve which is connected to a low-pressure hydraulic system. The low-pressure fluid connection 7 is closed by valve technology during the forming process.

FIG. 2 shows a basic sketch of a section through the device in the closed state during the forming process. Fig. 2 shows the press from Fig.

1 and therefore reference is made to the above description and the identical reference numbers.

In the closed state, the workpiece blank 8 is between the lower tool

2 and the upper tool 3 included. The upper tool 3 closes the press tightly and builds up a closing force in relation to the lower tool 2 and the workpiece 8 . A certain pressure is already applied to the workpiece 8 here. The workpiece 8 is arranged between the lower tool 2 and the upper tool 3 in such a way that it seals off the fluid basin 5 of the lower tool 2 . In addition, the semi-finished product forms a sealed space with the die 4 of the upper tool 3 when the upper tool 3 and the lower tool 2 are pressed together. Here, the upper tool 3 and the lower tool 2 in the region of the mounted workpiece 8 sealant (not shown), such as For example, have rubber lips that seal the interior of the press from the environment.

In the closed state of the press described above, the workpiece 8 is formed into the fluid basin 5 by means of high-pressure injection through the high-pressure fluid connection 6 . For this purpose, the high-pressure fluid is injected through the valve of the high-pressure fluid connection 6 into the fluid space in order to bring about an overpressure. The high-pressure fluid is provided from the high-pressure fluid reservoir, which permanently provides high pressure. The high-pressure pulse from the high-pressure fluid reservoir presses the workpiece 8 into the die 4 in the direction of the upper tool 3 and thus forms it in accordance with the mold contour. The build-up of pressure serves to form the workpiece into a formed component 9. FIG. 2 already shows the formed component 9, which was pressed into the die by the fluid. Here, the formed component 9 is shown with a bulge (longitudinal section through the component) from the workpiece, which was pressed against the mold contour of the die 4 by means of the high-pressure impulse with the fluid.

The device for high-pressure forming of workpieces 8 also has measuring technology (not shown) in order to be able to continuously measure the pressure of the fluid in the press. In this way, the desired pressure level in the press can be monitored and set.

The upper tool 3 preferably has a vent (not shown) in the area of the die 4 . Gas that is present in the sealed space between the workpiece 8 and the die 4 can thus escape from the upper tool 3 if it is displaced by the formed component 9 in the forming process.

FIG. 3 shows a basic sketch of a section through the device in a state after the forming process. FIG. 3 shows the press from FIG. 1. To avoid repetition, reference is made to the above description and the identical reference numbers.

After the forming, the press opens and the upper tool 3 is raised. The overpressure ensures that the fluid flows over the edge of the fluid basin 5 and forms a fluid film 10 . The fluid that has flowed out is balanced by added fluid from the low-pressure fluid port 7 .

Due to the surface tension or the flow force of the fluid, the formed component 9 can be transported out of the press by means of the fluid film 10 . Furthermore, an incoming workpiece 8 to be formed can be transported into the press on the fluid film 10 will. As a result, the workpiece 8 or the formed component 9 can be transported easily and gently. In this case, the fluid film 10 can also be formed by the fluid basin 5 being continuously filled with fluid via the low-pressure fluid connection 7 so that the overflowing fluid basin 5 forms a fluid film 10 at its edges. The overflowing fluid is caught by a catch basin (not shown) underneath the press. The overflowing fluid basin also prevents gases (air) from penetrating the fluid space and impairing the forming due to the compressibility.

The device also has a transport system (not shown). The transport system is directly adjacent to the press and is configured to transport workpieces 8 horizontally towards the device - and formed components 9 away from the device. The transport system is preferably configured as a (conveyor) belt. Workpieces 8 and formed components 9 can thus be transported gently on the (assembly) line. The transport system is supported by the fluid film 10 in the vicinity of the press, so that a smooth transition between the transport system and the press is ensured.

FIGS. 4 to 6 show a basic sketch of a section through an alternative embodiment of the device in a state before, during and after the forming process.

In the second (passive) exemplary embodiment, which is essentially based on the first (active) exemplary embodiment described above and has largely identical features with the exception of the differences mentioned below, the high-pressure fluid system and thus a cost item with regard to economic efficiency can be omitted. The process becomes simpler but also less controllable. In the second (passive) exemplary embodiment, the high-pressure pulse required for forming is generated in that the upper tool 3 with a plunging stamp 11 (engraving) hits the lower tool 2 and the workpiece 8 lying between them at high speed (pulse). When the upper tool 3 strikes, the workpiece 8 closes the fluid basin 5 and seals it, as shown in FIG. The workpiece 8 is pressed against the lower tool 2 by a hold-down device 12 which precedes the punch 11 . Then the punch 11 dips slightly into the workpiece 8 and presses it into the fluid basin 5, as shown in FIG. The fluid displaced in this way and subjected to a high-pressure pulse presses the workpiece 8 against the punch 11 and thus leads to the forming of the workpiece 8. After the forming, the press opens and the upper tool 3 in the form of the punch 11 and the hold-down device 12 is raised as shown in FIG. The stamp 11 is advantageously positive (patrix) formed in the second embodiment according to Figures 4-6, while in the first embodiment according to the Figures 1-3 the shaping engraving is designed as a negative matrix. In the case of the channels, the difference is small, but such that the stamp 11 in the passive variant can immerse so deeply that the fluid volume required for forming is displaced.

The present invention is not limited to the exemplary embodiments described. Further modifications and variations of the exemplary embodiments are conceivable. An exemplary embodiment would be possible in which the press is a crank or toggle press. All versions of the press can be closed and opened both mechanically and hydraulically.

In addition, an exemplary embodiment is disclosed in which the workpieces 8 to be processed are not workpiece blanks, but instead represent semi-finished products or blanks that have already been partially processed.

Furthermore, display devices that display the pressure level during the forming process, positions of the workpieces and the progress of the process are conceivable.

Reference List

1 platen, frame of the press, press table

2 lower tool

3 upper tool

4 shaping section, die, engraving

5 fluid pools

6 fluid port, high pressure channel

7 fluid connection, low-pressure channel

8 workpiece, semi-finished product, circuit board

9 formed component

10 fluid film

11 Shaping section, male part, punch

12 hold down, fixation section

Claims

PATENT CLAIMS Device for high-pressure forming of workpieces (8), in particular for the production of heat exchanger plates and bipolar plates, comprising: a mold with a shaping section (4, 11) and a fluid basin (5), between which the workpiece (8) for high-pressure forming can be arranged, characterized characterized in that the device is configured to generate a high-pressure pulse in the fluid pool (5), so that the workpiece (8) is urged against the shaping section (4, 11) by the high-pressure pulse. Device according to the preceding claim, characterized in that the device has at least one high-pressure fluid reservoir, the high-pressure pulse being able to be generated at least partially or completely by filling the fluid basin (5) with high-pressure fluid from the high-pressure fluid reservoir. Device according to one of the preceding claims, characterized in that the high-pressure pulse is generated at least partially or completely by closing the fluid basin (5), in particular with the workpiece, and reducing the volume of the fluid basin (5), in particular with the workpiece, to increase the Pressure of the fluid enclosed in the fluid basin (5) can be generated. Device according to one of the preceding claims, characterized in that the mold is formed from a lower tool (2) and an upper tool (3), the upper tool (3) preferably having the shaping section (4, 11) and the lower tool (2) having the Having fluid basin (5). Device according to one of the preceding claims, characterized in that the shaping section (4, 11) has the shape of a female (4) or male (5). Device according to one of the preceding claims, characterized in that the device has a fixing section (12) movable separately from the shaping section (4, 11) and configured to fix the workpiece (8) in relation to the fluid basin (5). Device according to one of the preceding claims, characterized in that the high-pressure fluid reservoir can communicate with the fluid reservoir (5) via a high-pressure channel (6), the device having at least one high-pressure valve for opening and closing the high-pressure channel (6 ) includes. Device according to one of the preceding claims, characterized in that the device comprises a transport device in order to transport workpieces (8) into and/or out of the mold, the transport device preferably being designed as a conveyor belt. Device according to one of the preceding claims, characterized in that the device has at least one low-pressure fluid reservoir which can communicate with the fluid basin (5) via a low-pressure channel (7) in order to fill the fluid basin (5) with low-pressure fluid, wherein the device preferably comprises at least one low-pressure valve for opening and closing the low-pressure channel (7). Device according to one of the preceding claims, characterized in that the mold can be transferred between an open position and a closed position, the device preferably having a pressing mechanism, preferably a crank or toggle lever pressing mechanism, to move the mold between the open position and the closed position to convert, wherein the press is particularly preferably mechanically or hydraulically actuated. Device according to one of the preceding claims, characterized in that the mold has at least one ventilation opening in order to discharge gas that is displaced during the shaping of the workpiece (8) from the shaping section (4, 11). Method for high-pressure forming of workpieces (8), in particular using the device according to one of the preceding claims, the method comprising the following steps:

Placing a workpiece (8) in a mold having a shaping section (4, 11) and a fluid pool (5) such that the workpiece (8) is located between the shaping section (4, 11) and the fluid pool (5);

Generating a high-pressure impulse in the fluid basin (5) in order to force the workpiece (8) against the shaping section (4, 11) by the high-pressure impulse. Method according to the preceding claim, characterized in that the high-pressure pulse is generated at least partially or completely by filling the fluid basin (5) with high-pressure fluid from the high-pressure fluid reservoir. Method according to one of the two preceding claims, characterized in that the high-pressure pulse at least partially or completely by closing the fluid pool (5), in particular with the workpiece, and 17

Reducing the volume of the fluid pool (5), in particular with the workpiece, to increase the pressure of the fluid pool (5) enclosed fluid is generated. Method according to one of the three preceding claims, characterized in that the fluid basin (5) is made to overflow when the workpiece (8) is transported into and/or out of the mold, so that the workpiece (8) rests on a fluid film (10) floats up. Method according to the preceding claim, characterized in that fluid is supplied to the fluid basin (5) during transport of the workpiece (8) into and/or out of the mold, preferably from a low-pressure fluid reservoir. Method according to one of the five preceding claims, characterized in that the workpiece (8) seals the fluid basin (5) when it is filled with high-pressure fluid and/or that a pressure in the fluid basin when the mold is opened is greater than the ambient pressure. Method according to one of the six preceding claims, characterized in that the volume of the high-pressure fluid which is supplied to the fluid basin (5) for the high-pressure forming of the workpiece (8), based on the surface of the workpiece (8) to be formed, is a maximum of 0.02 cm ³ per cm ² , preferably a maximum of 0.01 cm ³ per cm ² . Method according to one of the seven preceding claims, characterized in that a pressure of the high-pressure fluid is in the range of 200 to 500 MPa, preferably in the range of 300 to 500 MPa, preferably in the range of 400 to 500 MPa and/or that a pressure of the low-pressure fluid is in the range of 1 to 10 MPa, preferably in the range of 2 to 10 MPa, preferably in the range of 5 to 10 MPa.