EP2943297A1 - Method, tool and press for the electrohydraulic forming of a workpiece - Google Patents

Method, tool and press for the electrohydraulic forming of a workpiece

Info

Publication number
EP2943297A1
EP2943297A1 EP14700188.7A EP14700188A EP2943297A1 EP 2943297 A1 EP2943297 A1 EP 2943297A1 EP 14700188 A EP14700188 A EP 14700188A EP 2943297 A1 EP2943297 A1 EP 2943297A1
Authority
EP
European Patent Office
Prior art keywords
forming
cavity
shock wave
blank
wall
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP14700188.7A
Other languages
German (de)
French (fr)
Other versions
EP2943297B1 (en
Inventor
Gilles Avrillaud
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ADM28 SARL
Original Assignee
ADM28 SARL
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ADM28 SARL filed Critical ADM28 SARL
Publication of EP2943297A1 publication Critical patent/EP2943297A1/en
Application granted granted Critical
Publication of EP2943297B1 publication Critical patent/EP2943297B1/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D26/00—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces
    • B21D26/02—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure
    • B21D26/06—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure by shock waves
    • B21D26/12—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure by shock waves initiated by spark discharge
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B21D22/02—Stamping using rigid devices or tools
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B21D22/10—Stamping using yieldable or resilient pads
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B21D22/20—Deep-drawing
    • B21D22/22—Deep-drawing with devices for holding the edge of the blanks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B21D22/20—Deep-drawing
    • B21D22/30—Deep-drawing to finish articles formed by deep-drawing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D26/00—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces
    • B21D26/02—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure
    • B21D26/06—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure by shock waves

Definitions

  • the invention relates to a method of forming a part, in particular a piece of sheet metal, by applying a plastic deformation to a blank of material, having a reduced elastic return.
  • the invention also relates to a tool and a press used in this process.
  • stamping which consists in forcing a flat sheet blank between two forming parts (usually a punch and a matrix) each having an outer shape
  • the thickness of the sheet close to the desired shape of the piece to obtain. Several passes may be necessary to obtain the final shape of the part in order to distribute the deformations and avoid tearing of the sheet.
  • the stress applied to the sheet blank must exceed the elastic limit of the material used so as to cause permanent plastic deformation thereof.
  • the fraction of this stress absorbed by elastic deformation of the part induces an elastic return, particularly in the bending zones thereof, substantially modifying the dimensional characteristics obtained before unloading.
  • the shape of the punch and the die can be modified so as to
  • the part is initially formed by forming electrohydraulic or by conventional stamping, then mounted on a shaping tool comprising a punch against which the piece is violently plated by a pressure developed by an electric arc in the tank of an electrohydraulic forming tool.
  • a shaping tool comprising a punch against which the piece is violently plated by a pressure developed by an electric arc in the tank of an electrohydraulic forming tool.
  • Such a method is particularly expensive and difficult to implement. It requires in fact new machines and new tools and has disadvantages related to the use of a liquid, especially water, in the electrohydraulic forming process, namely sealing problems around the blank of material , risks of corrosion of the formed part, etc.
  • the process is not optimum since it requires a recovery of the piece to reposition it in a new tool after the first forming step.
  • the present invention therefore aims to provide a method of forming a workpiece without elastic return which does not have the disadvantages of the prior art.
  • the invention aims to provide such a reduced cost method adaptable on conventional stamping presses.
  • the invention also aims to provide a forming process that allows to combine the advantages of stamping forming and electro-hydraulic forming and to reduce or even eliminate the elastic return phenomena and internal stresses generated by a stamping press classic.
  • the invention also aims to provide a forming method in a single operation, without manipulation of the part between the different steps of the process.
  • the invention also relates to a forming tool adapted for implementing the method according to the invention.
  • the invention relates to a forming tool that can be mounted on a conventional stamping press and requires only minor modifications of the working environment.
  • the invention finally relates to a stamping press adapted to receive the forming tool and implement the forming method according to the invention.
  • the invention relates to a method of forming a workpiece by plastic deformation in which:
  • the press is actuated so as to exert a pressure, called the deformation pressure, capable of deforming the blank of material between the first and the second forming part,
  • At least one of the forming parts of the tool used comprises a cavity filled with a liquid and provided with means suitable for generating at least one shock wave in the cavity and through a wall of said forming portion, said wall being adapted to be substantially indeformable under the deformation pressure and to have a yield strength greater than a stress generated by the shock wave in the wall,
  • shock wave or pressure wave is indifferently used, it being understood that the pressure gradient of the pressure wave is sufficiently high to be assimilated to a wave of pressure. shock.
  • a sequence of operations similar to the sequence of operations of a conventional stamping is used, with a tooling (a punch / die pair) for which it is not necessary to modify the dimensions for compensate for springback.
  • this shock wave or pressure wave generated in the tool cavity passes through the wall of the tool and applies to the shaped material blank in a direction mainly orthogonal to its surface, that is to say according to its thickness.
  • the pressure wave By choosing the generation energy of the pressure wave so that the stress generated by the propagation of this wave through the materials it passes through is less than the elastic limit of the material of the tool to not damaging it and greater than the elastic limit of the material of the blank of material to be formed, the pressure wave generates in the blank of material a stress mainly orthogonal to its surface, in the plastic field, which reduces the longitudinal stresses parallel to the surface driven by the deformation of the blank of material in the tooling. This reduction of the longitudinal stresses is performed so as to compensate the longitudinal elastic return. Therefore, a possible springback occurs in the direction of the thickness of the part and causes very little deformation thereof at the opening of the tool.
  • the shock wave is generated by means of an electric arc triggered between two electrodes penetrating into the cavity.
  • a shock wave i.e., a pressure wave having a very high pressure gradient
  • This pressure wave moves away from the electric arc in all directions until it meets the inner face of the wall of the cavity. It is transmitted through this wall to the blank of material.
  • the conventional stamping process is coupled with a method derived from electrohydraulic forming, in contrast to which the shock wave does not plate the blank of material in contact with the liquid against a punch but is transmitted by the tooling.
  • the electric arc is obtained by a current pulse with an energy of between 10 and 100 kJ.
  • This energy is generated by the storage of an electric current in a battery of high voltage capacitors (from 2 kV to 300 kV, and preferably from 20 kV to 50 kV) and the rapid discharge thereof, for example by means of a spark gap, at the terminals of the electrodes.
  • a plurality of shock waves is generated sequentially, preferably two to four shock waves, without releasing the deformation pressure. It was found that depending on the material, its flatness and its deformation, the blank of material could not be in uniform contact with the forming parts despite the maintenance of the deformation pressure.
  • the application of a series of shock waves thus makes it possible to eliminate the partial contact points between the blank of material and the tooling and to obtain an orthogonal stress on the surface of the blank of material which is more homogeneous.
  • the invention also extends to a forming tool adapted for implementing the method of forming a workpiece by plastic deformation, comprising a first forming portion and a second forming portion, each forming portion comprising a face opposite the other part having an external shape complementary to the shape to be obtained on the part, characterized in that at least one of the forming parts comprises a cavity filled with a liquid and provided with means of generating least a wave of impact in the cavity and through a wall of said forming portion, said wall being adapted to be substantially indeformable under a deformation pressure applied between the forming parts and to have a yield strength greater than a stress generated by the shock wave.
  • a cavity filled with liquid for example water
  • the cavity is preferably closed, for example by a plug, but could also be open on a relatively small part of its area without changing its function.
  • the means for generating a shock wave comprise at least one electrode plunging into the cavity and connected to a pulsed high power generator adapted to provide a current pulse with an energy of between 10. and 100 kJ.
  • a pulsed high power generator adapted to provide a current pulse with an energy of between 10. and 100 kJ.
  • the shock wave for example by vaporization of the liquid by means of an electric arc, it suffices to have a single electrode immersed in the cavity, the second electrode being made by the wall itself of the tool of forming.
  • the tooling comprises at least one pair of electrodes passing through the wall of the cavity through insulating bushings. If it is possible to use only one electrode, it is however preferable to use two electrodes insulated from the wall of the forming tool in order to be able to adjust the inter-electrode distance and to avoid passing an electrode. electrical current in the wall of the forming tool to minimize the risk of electro-corrosion. Furthermore, depending on the size of the tool, it may be useful to have several pairs of electrodes so as to generate in parallel several shock waves from points distributed in the tooling in order to standardize the pressure wave over the entire surface of the room.
  • the electrodes of at least one pair of electrodes are connected by a metal wire adapted to be vaporized during the application of the current pulse.
  • a metal wire adapted to be vaporized during the application of the current pulse.
  • Such a filament, or thread explosive when it is crossed by a current of high intensity, vaporizes and forms a plasma which, itself, generates a large amount of gas which causes a shock wave.
  • the forming part comprising the cavity comprises means for replacing the liquid inside thereof.
  • the repetition of electrical discharges causing the shock waves, especially in series production, can cause pollution of the liquid of the cavity. It is then useful to provide the portion of the tooling comprising the cavity with means for renewing this liquid, for example by providing a water supply duct and an evacuation duct, both provided with a control valve. stop, or under permanent pressure, adapted to allow a continuous renewal or at regular intervals of the liquid contained in the cavity.
  • the invention also extends to a stamping press provided with a tool having at least one of the features mentioned above.
  • a stamping press provided with a tool having at least one of the features mentioned above.
  • a "conventional" stamping press can be used with a tool according to the invention, by adding to this press a generator of appropriate electrical pulses and a device for circulating the water in the tool cavity. . Therefore, the equipment of an existing stamping shop is possible at reduced costs and without causing major modification of the equipment.
  • the invention also relates to a forming method, a forming tool and a stamping press characterized in combination by all or some of the characteristics mentioned above or below.
  • FIG. 1 shows a schematic section of a tool according to the invention mounted on a suitable press.
  • FIG. 2 schematically represents the steps of the method according to the invention.
  • the press 10 shown in FIG. 1 in the form of a column press comprises a frame 11 on which guide columns 12 make it possible to guide the tools, for example a tooling gate 13 adapted to slide along the columns 12 under the the force of a main cylinder 14 or a blank holder 16 sliding under the effect of a secondary cylinder 15.
  • the tool 20 consists of a first forming portion or matrix 21 fixed to the frame 11 and a second forming part or punch 23 fixed on the tooling gate 13.
  • the die 21 and the punch 23 have respective surfaces 22 and 24 whose shape is complementary so as to be able to deform a blank of material 18, for example a sheet metal plate metal, steel or aluminum.
  • the punch 23 comprises a cavity 26 filled with liquid 27.
  • the liquid 27 is generally water, preferably undistilled so as to have a non-zero conductivity.
  • the cavity 26 is delimited, at least opposite the matrix 21 by a thick wall 25 whose outer surface 24 defines, in cooperation with the surface 22 of the matrix 21, the shape of the part to be obtained.
  • the thickness of the wall 25 is determined according to the material of the punch and the deformation forces necessary to form the blank of material.
  • the punch 23 as the die 21 are made of hardened alloy steel, having an elastic limit of the order of 500 to 1500 MPa.
  • Two electrodes 28 penetrate inside the cavity 26 through insulating bushings 29 and dive into the liquid 27.
  • the two electrodes 28 are connected to a high power pulsed generator 17 comprising a plurality of high voltage capacitors adapted to store a energy between 10 and 100 kJ and a means of rapid discharge of these capacitors, for example a spark gap, across the electrodes.
  • a high power arc is established between the two electrodes and instantaneously vaporizes the liquid 27 in the vicinity of the electric arc, which makes it possible to generate a pressure wave presenting a very strong pressure gradient, that is to say a shock wave, at the level of the arc electric and propagates radially in all directions.
  • Electrodes are possible, such as for example using a single electrode penetrating into the cavity through a sealed passage, the second electrode being formed by the punch itself, connected to ground. It is also possible to use a coaxial cable of which a part is stripped, the ground strap and the core of the cable thus forming two electrodes. In addition, in the case of large tools, intended for stamping large parts, it may be useful to install several pairs of electrodes at different points of the cavity and to couple them either in series or in series. parallel to the same generator 17 of appropriate power, or to several generators controlled in synchronism so as to generate several shock waves in parallel to produce a resulting pressure wave uniformly covering the entire surface 24 in contact with the blank of material 18 .
  • the means for generating a shock wave may also comprise a metal filament connected between the two electrodes 28.
  • the filament also called explosive wire
  • This plasma in turn generates vaporization of the surrounding water and generates a shock wave.
  • the tool may also comprise a plurality of pairs of electrodes connected, for at least some of them, by explosive wires so as to be able to generate several successive shock waves without having to intervene on the tooling to replace the wire explosive destroyed by the first shock wave.
  • the punch 23 may also comprise liquid feed / discharge lines 27 in the cavity 26 to allow the liquid to be renewed.
  • the lines 30 may be provided with a stop valve 31 even if these valves 'stop are not absolutely necessary, the liquid in the cavity can be pressurized by a permanent supply, or even be left at atmospheric pressure.
  • the jacks of the press 10 are controlled so as to keep the tooling 20 open, that is to say that the punch 23 and the blank clamp 16 are spaced from the die 21. then places a blank of material 18 on the die 21.
  • the secondary jack 15 of the press is actuated so as to bring the blank clamp 16 of the die 21 and to hold and immobilize the blank of material 18 between the blank and the matrix.
  • step S 103 the main ram 14 of the press is actuated to lower the punch 23 to the die. Under the effect of the deformation pressure P, the blank of material 18 is deformed between the punch 23 and the die 21 to acquire the desired final shape.
  • the deformation pressure P is then maintained between the punch 23 and the die 21 and, in step S 104, an electric arc is triggered between the electrodes 28 so as to generate a shock wave symbolized by the arrows moving radially away from each other. of the electric arc.
  • the application of an energy of the order of 50 kJ between the electrodes 28 generates a dynamic pressure wave having an amplitude of the order of 500 MPa which diffuses in the cavity 26 to to meet the inner face of the wall 25.
  • This pressure wave with some losses related to the reflections on the inner face of the wall 25, is communicated in the form of a stress to the wall 25, then to the blank of material 18 before to spread through the matrix 21 to the frame 11 of the press.
  • the stress generated in the wall 25 of the punch 23, as in the blank of material 18, by this pressure wave is of the order of 300 MPa. This stress is lower than the elastic limit of the punch material, which is greater than 700 MPa, and therefore does not cause any plastic deformation of the punch whose shape is retained.
  • Step S 104 may be repeated several times, without releasing the deformation pressure P.
  • the inventors have indeed also found that during the deformation of the material blank 18 in step S 103, parasitic deformations such as ripples of small amplitude on the surface of the formed part could prevent close contact between the punch 23 and the workpiece, thereby degrading the transmission of orthogonal stress to the workpiece surface.
  • the application of the first shock waves during the repetition of the step S 104 makes it possible to improve the contact between the punch and the workpiece by releasing the surface stresses at the contact points and by smoothing these corrugations.
  • the following shock waves make it possible to transmit the mainly orthogonal stress to the entire surface of the part.
  • a blank of material 18 aluminum 6061 T4, disc-shaped 250 mm in diameter is pressed cone-shaped 50 mm deep.
  • the elastic return is measured on the depth of the cone.
  • step S 104 it is possible to repeat the step S 104 relatively quickly, the repetition frequency being conditioned only by the recharging of the generator 17. It is not no more necessary to provide, between each repetition of step S 104, handling of the workpiece, the latter remaining in the tooling 20.
  • step S 104 Since the repetition of step S 104 is liable to pollute the liquid 27, it can be provided to change it either after a certain number of repetitions or by providing a permanent circulation of liquid between the pipes 30.
  • step S 105 After applying a number of shock waves corresponding to the desired accuracy and the material used for the material blank 18, step S 105 in which the cylinders 14 and 15 are actuated to raise the punch 23 and the blank clamp 16. It is then possible to clear the formed part, which has practically no springback.
  • the press 10 is a conventional hydraulic press, of the column press type in the example described, to which the pulsed high power generator 17 has been added and, if appropriate, a supply circuit for the liquid 27. thus possible to use an existing stamping workshop without major modification of the machines for the implementation of the forming process according to the invention.
  • the part of the forming tool comprising the cavity 26 is not necessarily the punch 23 but could be symmetrically the matrix 21. It will also be possible to perform the conventional stamping steps by means of one or several conventional punch (s) and use the punch 23 having the cavity 26 that during the last stamping pass or after the latter passes. However, it will be necessary to reinforce the piece 18 before generating the shock wave.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Shaping Metal By Deep-Drawing, Or The Like (AREA)

Abstract

The invention concerns a method for forming a workpiece by pressing that eliminates elastic return, which involves using a tool (20) of which at least one of the forming portions (21; 23) comprises a cavity (26) filled with a liquid (27) and provided with electrodes (28) capable of generating at least one shock wave in the cavity and through the wall (25) of said forming portion, deforming a material blank (18) between the two forming portions under the effect of a deformation pressure, and generating, without releasing the deformation pressure, at least one shock wave in the cavity such that the shock wave passes through the material blank orthogonally to the surface of same. The invention also concerns a tool (20) and a press (10) suitable for implementing the method.

Description

PROCEDE, OUTILLAGE ET PRESSE DE FORMAGE ÉLECTROHYDRAULIQUE D'UNE PIECE  METHOD, TOOLING AND PRESS FOR ELECTROHYDRAULIC FORMING OF A PIECE
L'invention concerne un procédé de formage d'une pièce, notamment d'une pièce en tôle métallique, par application d'une déformation plastique à un flan de matière, présentant un retour élastique réduit. L'invention 5 concerne également un outillage et une presse utilisée dans ce procédé. The invention relates to a method of forming a part, in particular a piece of sheet metal, by applying a plastic deformation to a blank of material, having a reduced elastic return. The invention also relates to a tool and a press used in this process.
L'un des procédés les plus utilisés pour le formage de pièces en tôle, telles que des pièces de carrosserie d'automobiles, est l'emboutissage qui consiste à contraindre un flan de tôle plat entre deux parties de formage (usuellement un poinçon et une matrice) présentant chacun une forme extérieure One of the most commonly used methods for forming sheet metal parts, such as automobile body parts, is stamping which consists in forcing a flat sheet blank between two forming parts (usually a punch and a matrix) each having an outer shape
10 sensiblement identique, à l'épaisseur de la tôle près, à la forme souhaitée de la pièce à obtenir. Plusieurs passes peuvent être nécessaires pour obtenir la forme finale de la pièce afin de répartir les déformations et éviter le déchirement de la tôle. La contrainte appliquée au flan de tôle doit excéder la limite élastique de la matière utilisée de manière à entraîner une déformation plastique permanente de celle-ci.10 substantially identical, the thickness of the sheet close to the desired shape of the piece to obtain. Several passes may be necessary to obtain the final shape of the part in order to distribute the deformations and avoid tearing of the sheet. The stress applied to the sheet blank must exceed the elastic limit of the material used so as to cause permanent plastic deformation thereof.
15 Cependant, lorsque la contrainte appliquée est relâchée, la fraction de cette contrainte absorbée par déformation élastique de la pièce induit un retour élastique, particulièrement dans les zones de flexion de celle-ci, modifiant sensiblement les caractéristiques dimensionnelles obtenues avant déchargement. Pour compenser ce retour élastique, on peut modifier la forme du poinçon et de la matrice de manière àHowever, when the applied stress is relaxed, the fraction of this stress absorbed by elastic deformation of the part induces an elastic return, particularly in the bending zones thereof, substantially modifying the dimensional characteristics obtained before unloading. To compensate for this elastic return, the shape of the punch and the die can be modified so as to
20 prendre en compte le retour élastique. Dès lors, la mise au point d'un outil de formage prenant en compte ce retour élastique est délicate. De plus, à chaque variation de matière (entraînant une variation de la limite élastique de celle-ci), la compensation du retour élastique n'est pas parfaite, ce qui engendre des écarts dimensionnels d'une pièce à l'autre. De ce fait, il est usuel de prévoir plusieurs20 take into account the elastic return. Therefore, the development of a forming tool taking into account this elastic return is delicate. In addition, with each variation of material (causing a variation of the elastic limit thereof), the compensation of the springback is not perfect, which causes dimensional deviations from one part to another. As a result, it is customary to
25 étapes d'emboutissage avec des jeux de poinçon et de matrice présentant des degrés croissants de compensation du retour élastique. 25 stamping steps with punch and die sets having increasing degrees of springback compensation.
On connaît du document US 2009/0272167 un procédé de formage d'une pièce comportant une première étape de formage et une deuxième étape de conformation permettant d'obtenir une pièce conforme aux dimensions Document US 2009/0272167 discloses a process for forming a part comprising a first forming step and a second conformation step making it possible to obtain a part conforming to the dimensions
30 prévues. Dans ce procédé, la pièce est initialement formée par formage électrohydraulique ou par emboutissage classique, puis montée sur un outil de conformation comportant un poinçon contre lequel la pièce est violemment plaquée par une pression développée par un arc électrique dans la cuve d'un outil de formage électrohydraulique. Un tel procédé est particulièrement coûteux et difficile à mettre en œuvre. Il nécessite en effet de nouvelles machines et de nouveaux outillages et présente des inconvénients liés à l'utilisation d'un liquide, notamment de l'eau, dans le procédé de formage électrohydraulique, à savoir des problèmes d'étanchéité autour du flan de matière, des risques de corrosion de la pièce formée, etc. De plus, le procédé n'est pas optimum puisqu'il nécessite une reprise de la pièce pour la repositionner dans un nouvel outillage après la première étape de formage. 30 planned. In this process, the part is initially formed by forming electrohydraulic or by conventional stamping, then mounted on a shaping tool comprising a punch against which the piece is violently plated by a pressure developed by an electric arc in the tank of an electrohydraulic forming tool. Such a method is particularly expensive and difficult to implement. It requires in fact new machines and new tools and has disadvantages related to the use of a liquid, especially water, in the electrohydraulic forming process, namely sealing problems around the blank of material , risks of corrosion of the formed part, etc. In addition, the process is not optimum since it requires a recovery of the piece to reposition it in a new tool after the first forming step.
La présente invention vise donc à fournir un procédé de formage d'une pièce sans retour élastique qui ne présente pas les inconvénients de la technique antérieure. En particulier, l'invention vise à fournir un tel procédé de coût réduit adaptable sur les presses d'emboutissage classiques.  The present invention therefore aims to provide a method of forming a workpiece without elastic return which does not have the disadvantages of the prior art. In particular, the invention aims to provide such a reduced cost method adaptable on conventional stamping presses.
L'invention vise également à fournir un procédé de formage qui permette de cumuler les avantages du formage par emboutissage et du formage électrohydraulique et de réduire, voire même de supprimer, les phénomènes de retour élastique et de contraintes internes générés par une presse d'emboutissage classique.  The invention also aims to provide a forming process that allows to combine the advantages of stamping forming and electro-hydraulic forming and to reduce or even eliminate the elastic return phenomena and internal stresses generated by a stamping press classic.
L'invention vise en outre à fournir un procédé de formage en une seule opération, sans manipulation de la pièce entre les différentes étapes du procédé.  The invention also aims to provide a forming method in a single operation, without manipulation of the part between the different steps of the process.
L'invention vise également un outillage de formage adapté pour la mise en œuvre du procédé selon l'invention. En particulier, l'invention vise un outillage de formage qui puisse être monté sur une presse d'emboutissage classique et ne nécessite que des modifications mineures de l'environnement de travail.  The invention also relates to a forming tool adapted for implementing the method according to the invention. In particular, the invention relates to a forming tool that can be mounted on a conventional stamping press and requires only minor modifications of the working environment.
L'invention vise enfin une presse d'emboutissage adaptée pour recevoir l'outillage de formage et mettre en œuvre le procédé de formage selon l'invention. Pour ce faire, l'invention concerne un procédé de formage d'une pièce par déformation plastique dans lequel : The invention finally relates to a stamping press adapted to receive the forming tool and implement the forming method according to the invention. To do this, the invention relates to a method of forming a workpiece by plastic deformation in which:
a) on utilise une presse munie d'un outillage comportant une première partie de formage et une deuxième partie de formage, chaque partie de formage comportant une face en regard de l'autre partie présentant une forme externe complémentaire d'une forme de pièce à obtenir,  a) using a press equipped with a tooling comprising a first forming part and a second forming part, each forming part having a face facing the other part having an external shape complementary to a piece form to get,
b) on insère un flan de matière entre la première et la deuxième partie de formage,  b) inserting a blank of material between the first and the second forming part,
c) on actionne la presse de manière à exercer une pression, dite pression de déformation, propre à déformer le flan de matière entre la première et la deuxième partie de formage,  c) the press is actuated so as to exert a pressure, called the deformation pressure, capable of deforming the blank of material between the first and the second forming part,
caractérisé en ce que l'une au moins des parties de formage de l'outillage utilisé comporte une cavité remplie d'un liquide et munie de moyens propres à générer au moins une onde de choc dans la cavité et au travers d'une paroi de ladite partie de formage, ladite paroi étant adaptée pour être sensiblement indéformable sous la pression de déformation et pour présenter une limite élastique supérieure à une contrainte générée par l'onde de choc dans la paroi, characterized in that at least one of the forming parts of the tool used comprises a cavity filled with a liquid and provided with means suitable for generating at least one shock wave in the cavity and through a wall of said forming portion, said wall being adapted to be substantially indeformable under the deformation pressure and to have a yield strength greater than a stress generated by the shock wave in the wall,
et en ce que : and in that :
d) on maintient la pression de déformation entre les parties de formage après déformation du flan de matière,  d) maintaining the deformation pressure between the forming parts after deformation of the blank of material,
e) on génère dans la cavité au moins une onde de choc de telle sorte que l'onde de choc traverse le flan de matière sensiblement orthogonalement à sa surface,  e) generating in the cavity at least one shock wave so that the shock wave passes through the blank of material substantially orthogonal to its surface,
f) on relâche la pression de déformation du flan de matière et on éjecte celui-ci.  f) releasing the deformation pressure of the material blank and ejecting it.
Dans le texte de la présente description, on emploie de manière indifférente le terme d'onde de choc ou d'onde de pression, étant entendu que le gradient de pression de l'onde de pression est suffisamment élevé pour être assimilé à une onde de choc. Dans ce procédé, on utilise une séquence d'opérations analogues à la séquence d'opérations d'un emboutissage classique, avec un outillage (un couple poinçon, matrice) pour lequel il n'est pas nécessaire d'effectuer des modifications de cotes pour compenser le retour élastique. En maintenant la pièce sous pression dans l'outillage et en générant une onde de choc dans l'une des parties de l'outillage, poinçon ou matrice, cette onde de choc ou onde de pression générée dans la cavité de l'outillage traverse la paroi de l'outil et s'applique au flan de matière en forme selon une direction principalement orthogonale à sa surface, c'est-à-dire selon son épaisseur. En choisissant l'énergie de génération de l'onde de pression de telle sorte que la contrainte générée par la propagation de cette onde au travers des matériaux qu'elle traverse soit inférieure à la limite élastique de la matière de l'outil pour ne pas endommager celui-ci et supérieure à la limite élastique de la matière du flan de matière à former, l'onde de pression génère dans le flan de matière une contrainte principalement orthogonale à sa surface, dans le domaine plastique, qui vient réduire les contraintes longitudinales parallèles à la surface entraînées par la déformation du flan de matière dans l'outillage. Cette réduction des contraintes longitudinales est réalisée de sorte à compenser le retour élastique longitudinal. Dès lors, un retour élastique éventuel s'effectue dans la direction de l'épaisseur de la pièce et n'entraîne que très peu de déformations de celle-ci à l'ouverture de l'outillage. De ce fait, il n'est plus nécessaire de prévoir des opérations d'emboutissage et/ou de conformation ultérieures, ce qui supprime des opérations supplémentaires par rapport à un procédé classique d'emboutissage. Il n'est pas non plus nécessaire d'opérer des reprises de la pièce formée dans une opération de conformation ultérieure, la conformation de la pièce à ses dimensions nominales s'effectuant dans la même opération que sa déformation initiale. Le procédé selon l'invention est donc particulièrement économique par rapport aux procédés connus. In the text of the present description, the term shock wave or pressure wave is indifferently used, it being understood that the pressure gradient of the pressure wave is sufficiently high to be assimilated to a wave of pressure. shock. In this method, a sequence of operations similar to the sequence of operations of a conventional stamping is used, with a tooling (a punch / die pair) for which it is not necessary to modify the dimensions for compensate for springback. By keeping the workpiece under pressure in the tooling and by generating a shock wave in one of the parts of the tooling, punch or die, this shock wave or pressure wave generated in the tool cavity passes through the wall of the tool and applies to the shaped material blank in a direction mainly orthogonal to its surface, that is to say according to its thickness. By choosing the generation energy of the pressure wave so that the stress generated by the propagation of this wave through the materials it passes through is less than the elastic limit of the material of the tool to not damaging it and greater than the elastic limit of the material of the blank of material to be formed, the pressure wave generates in the blank of material a stress mainly orthogonal to its surface, in the plastic field, which reduces the longitudinal stresses parallel to the surface driven by the deformation of the blank of material in the tooling. This reduction of the longitudinal stresses is performed so as to compensate the longitudinal elastic return. Therefore, a possible springback occurs in the direction of the thickness of the part and causes very little deformation thereof at the opening of the tool. Therefore, it is no longer necessary to provide subsequent stamping and / or shaping operations, which eliminates additional operations compared to a conventional stamping process. It is also not necessary to rework the formed part in a subsequent shaping operation, the shaping of the piece to its nominal dimensions taking place in the same operation as its initial deformation. The method according to the invention is therefore particularly economical compared to known methods.
Avantageusement et selon l'invention, on génère l'onde de choc au moyen d'un arc électrique déclenché entre deux électrodes pénétrant dans la cavité. En créant un arc électrique de forte puissance entre les deux électrodes, la vaporisation quasi instantanée du liquide sur le trajet de l'arc électrique déclenche une onde de choc (c'est-à-dire une onde de pression présentant un gradient de pression très élevé) à l'intérieur de la cavité. Cette onde de pression s'éloigne de l'arc électrique dans toutes les directions jusqu'à rencontrer la face intérieure de la paroi de la cavité. Elle se transmet au travers de cette paroi jusqu'au flan de matière. On couple ainsi le procédé d'emboutissage classique avec un procédé dérivé du formage électrohydraulique, à la différence duquel l'onde de choc ne plaque pas le flan de matière au contact du liquide contre un poinçon mais est transmise par l'outillage. Advantageously and according to the invention, the shock wave is generated by means of an electric arc triggered between two electrodes penetrating into the cavity. By creating a high-power arc between the two electrodes, the almost instantaneous vaporization of the liquid in the path of the electric arc triggers a shock wave (i.e., a pressure wave having a very high pressure gradient) within the cavity. This pressure wave moves away from the electric arc in all directions until it meets the inner face of the wall of the cavity. It is transmitted through this wall to the blank of material. In this way, the conventional stamping process is coupled with a method derived from electrohydraulic forming, in contrast to which the shock wave does not plate the blank of material in contact with the liquid against a punch but is transmitted by the tooling.
Avantageusement et selon l'invention, l'arc électrique est obtenu par une impulsion de courant d'une énergie comprise entre 10 et 100 kJ. Cette énergie est générée par le stockage d'un courant électrique dans une batterie de condensateurs à haute tension (de 2 kV à 300 kV, et préférentiellement de 20 kV à 50 kV) et la décharge rapide de celui-ci, par exemple au moyen d'un éclateur, aux bornes des électrodes.  Advantageously and according to the invention, the electric arc is obtained by a current pulse with an energy of between 10 and 100 kJ. This energy is generated by the storage of an electric current in a battery of high voltage capacitors (from 2 kV to 300 kV, and preferably from 20 kV to 50 kV) and the rapid discharge thereof, for example by means of a spark gap, at the terminals of the electrodes.
Avantageusement et selon l'invention, on génère séquentiellement une pluralité d'ondes de choc, préférentiellement de deux à quatre ondes de choc, sans relâcher la pression de déformation. On a pu constater qu'en fonction de la matière, de sa planéité et de sa déformation, le flan de matière pouvait ne pas être en contact uniforme avec les parties de formage malgré le maintien de la pression de déformation. L'application d'une série d'ondes de choc permet ainsi de supprimer les points de contact partiel entre le flan de matière et l'outillage et d'obtenir une contrainte orthogonale à la surface du flan de matière qui est plus homogène.  Advantageously and according to the invention, a plurality of shock waves is generated sequentially, preferably two to four shock waves, without releasing the deformation pressure. It was found that depending on the material, its flatness and its deformation, the blank of material could not be in uniform contact with the forming parts despite the maintenance of the deformation pressure. The application of a series of shock waves thus makes it possible to eliminate the partial contact points between the blank of material and the tooling and to obtain an orthogonal stress on the surface of the blank of material which is more homogeneous.
L'invention s'étend également à un outillage de formage adapté pour la mise en œuvre du procédé de formage d'une pièce par déformation plastique, comportant une première partie de formage et une deuxième partie de formage, chaque partie de formage comportant une face en regard de l'autre partie présentant une forme externe complémentaire de la forme à obtenir sur la pièce, caractérisé en ce que l'une au moins des parties de formage comporte une cavité remplie d'un liquide et munie de moyens propres à générer au moins une onde de choc dans la cavité et au travers d'une paroi de ladite partie de formage, ladite paroi étant adaptée pour être sensiblement indéformable sous une pression de déformation appliquée entre les parties de formage et pour présenter une limite élastique supérieure à une contrainte générée par l'onde de choc. Ainsi, en ménageant une cavité remplie de liquide, par exemple de l'eau, à l'intérieur de l'une des parties de l'outillage de formage, on peut générer une onde de choc dans l'outillage qui se transmet au flan de matière sans pour autant que celui-ci soit en contact avec le liquide. La cavité est préférentiellement fermée, par exemple par un bouchon, mais pourrait être également ouverte sur une partie relativement faible de sa superficie sans pour autant modifier sa fonction. The invention also extends to a forming tool adapted for implementing the method of forming a workpiece by plastic deformation, comprising a first forming portion and a second forming portion, each forming portion comprising a face opposite the other part having an external shape complementary to the shape to be obtained on the part, characterized in that at least one of the forming parts comprises a cavity filled with a liquid and provided with means of generating least a wave of impact in the cavity and through a wall of said forming portion, said wall being adapted to be substantially indeformable under a deformation pressure applied between the forming parts and to have a yield strength greater than a stress generated by the shock wave. Thus, by providing a cavity filled with liquid, for example water, inside one of the parts of the forming tool, one can generate a shock wave in the tool which is transmitted to the blank of matter without it being in contact with the liquid. The cavity is preferably closed, for example by a plug, but could also be open on a relatively small part of its area without changing its function.
Avantageusement et selon l'invention, les moyens de génération d'une onde de choc comprennent au moins une électrode plongeant dans la cavité et reliée à un générateur de forte puissance puisée, adapté pour fournir une impulsion de courant d'une énergie comprise entre 10 et 100 kJ. Pour générer l'onde de choc, par exemple par vaporisation du liquide au moyen d'un arc électrique, il suffit d'une seule électrode plongeant dans la cavité, la seconde électrode étant réalisée par la paroi elle-même de l'outillage de formage.  Advantageously and according to the invention, the means for generating a shock wave comprise at least one electrode plunging into the cavity and connected to a pulsed high power generator adapted to provide a current pulse with an energy of between 10. and 100 kJ. To generate the shock wave, for example by vaporization of the liquid by means of an electric arc, it suffices to have a single electrode immersed in the cavity, the second electrode being made by the wall itself of the tool of forming.
Avantageusement et selon l'invention, l'outillage comporte au moins une paire d'électrodes traversant la paroi de la cavité par des traversées isolantes. S'il est possible d'utiliser qu'une seule électrode, il est cependant préférable d'utiliser deux électrodes isolées de la paroi de l'outillage de formage afin de pouvoir régler la distance inter-électrode et d'éviter de faire passer un courant électrique dans la paroi de l'outillage de formage pour minimiser les risques d'électro-corrosion. Par ailleurs, en fonction de la taille de l'outillage, il peut être utile de disposer de plusieurs paires d'électrodes de manière à générer en parallèle plusieurs ondes de choc à partir de points répartis dans l'outillage afin d'uniformiser l'onde de pression sur toute la surface de la pièce.  Advantageously and according to the invention, the tooling comprises at least one pair of electrodes passing through the wall of the cavity through insulating bushings. If it is possible to use only one electrode, it is however preferable to use two electrodes insulated from the wall of the forming tool in order to be able to adjust the inter-electrode distance and to avoid passing an electrode. electrical current in the wall of the forming tool to minimize the risk of electro-corrosion. Furthermore, depending on the size of the tool, it may be useful to have several pairs of electrodes so as to generate in parallel several shock waves from points distributed in the tooling in order to standardize the pressure wave over the entire surface of the room.
Avantageusement et selon l'invention, les électrodes d'au moins une paire d'électrodes sont reliées par un fil métallique adapté pour être vaporisé lors de l'application de l'impulsion de courant. Un tel filament, ou fil explosible, lorsqu'il est traversé par un courant de forte intensité, se vaporise et forme un plasma qui, lui-même, engendre une grande quantité de gaz qui provoque une onde de choc. En utilisant plusieurs paires d'électrodes munies chacune d'un fil explosible, il est possible de générer successivement plusieurs ondes de choc sans avoir besoin de remplacer le fil explosible de la première paire d'électrodes. Advantageously and according to the invention, the electrodes of at least one pair of electrodes are connected by a metal wire adapted to be vaporized during the application of the current pulse. Such a filament, or thread explosive, when it is crossed by a current of high intensity, vaporizes and forms a plasma which, itself, generates a large amount of gas which causes a shock wave. By using several pairs of electrodes each provided with an explosive wire, it is possible to successively generate several shock waves without having to replace the explosive wire of the first pair of electrodes.
Avantageusement et selon l'invention, la partie de formage comportant la cavité comporte des moyens de renouvellement du liquide à l'intérieur de celle-ci. La répétition des décharges électriques provoquant les ondes de choc, particulièrement en production de série, peut entraîner une pollution du liquide de la cavité. Il est alors utile de munir la partie de l'outillage comportant la cavité de moyens de renouvellement de ce liquide, en prévoyant par exemple un conduit d'approvisionnement en eau et un conduit d'évacuation, tous deux munis d'une vanne d'arrêt, ou encore sous pression permanente, adaptés pour permettre un renouvellement continu ou à intervalles réguliers du liquide contenu dans la cavité.  Advantageously and according to the invention, the forming part comprising the cavity comprises means for replacing the liquid inside thereof. The repetition of electrical discharges causing the shock waves, especially in series production, can cause pollution of the liquid of the cavity. It is then useful to provide the portion of the tooling comprising the cavity with means for renewing this liquid, for example by providing a water supply duct and an evacuation duct, both provided with a control valve. stop, or under permanent pressure, adapted to allow a continuous renewal or at regular intervals of the liquid contained in the cavity.
L'invention s'étend également à une presse d'emboutissage munie d'un outillage présentant au moins l'une des caractéristiques citées ci-avant. Ainsi, une presse d'emboutissage « classique » peut être utilisée avec un outillage selon l'invention, en adjoignant à cette presse un générateur d'impulsions électriques appropriées et un dispositif propre à faire circuler l'eau dans la cavité de l'outillage. Dès lors, l'équipement d'un atelier d'emboutissage existant est possible à coûts réduits et sans entraîner de modification majeure de l'équipement.  The invention also extends to a stamping press provided with a tool having at least one of the features mentioned above. Thus, a "conventional" stamping press can be used with a tool according to the invention, by adding to this press a generator of appropriate electrical pulses and a device for circulating the water in the tool cavity. . Therefore, the equipment of an existing stamping shop is possible at reduced costs and without causing major modification of the equipment.
L'invention concerne également un procédé de formage, un outillage de formage et une presse d'emboutissage caractérisés en combinaison par tout ou partie des caractéristiques mentionnées ci-dessus ou ci-après.  The invention also relates to a forming method, a forming tool and a stamping press characterized in combination by all or some of the characteristics mentioned above or below.
D'autres buts, caractéristiques et avantages de l'invention apparaîtront au vu de la description qui va suivre et des dessins annexés dans lesquels :  Other objects, features and advantages of the invention will become apparent from the following description and the appended drawings in which:
- la figure 1 représente une coupe schématique d'un outillage selon l'invention monté sur une presse adaptée. - La figure 2 représente schématiquement les étapes du procédé selon l'invention. - Figure 1 shows a schematic section of a tool according to the invention mounted on a suitable press. FIG. 2 schematically represents the steps of the method according to the invention.
La presse 10 représentée à la figure 1 sous la forme d'une presse à colonnes comprend un bâti 11 sur lequel des colonnes 12 de guidage permettent de guider les outillages, par exemple un porte outillage 13 adapté pour coulisser le long des colonnes 12 sous l'effort d'un vérin principal 14 ou encore un serre-flan 16 coulissant sous l'effet d'un vérin secondaire 15. L'outillage 20 est constitué d'une première partie de formage ou matrice 21 fixée sur le bâti 11 et une deuxième partie de formage ou poinçon 23 fixé sur le porte outillage 13. La matrice 21 et le poinçon 23 présentent des surfaces respectives 22 et 24 dont la forme est complémentaire de manière à pouvoir déformer un flan de matière 18, par exemple une plaque de tôle métallique, en acier ou en aluminium.  The press 10 shown in FIG. 1 in the form of a column press comprises a frame 11 on which guide columns 12 make it possible to guide the tools, for example a tooling gate 13 adapted to slide along the columns 12 under the the force of a main cylinder 14 or a blank holder 16 sliding under the effect of a secondary cylinder 15. The tool 20 consists of a first forming portion or matrix 21 fixed to the frame 11 and a second forming part or punch 23 fixed on the tooling gate 13. The die 21 and the punch 23 have respective surfaces 22 and 24 whose shape is complementary so as to be able to deform a blank of material 18, for example a sheet metal plate metal, steel or aluminum.
Dans l'exemple représenté à la figure 1, le poinçon 23 comprend une cavité 26 remplie de liquide 27. Le liquide 27 est en général de l'eau, préférentiellement non distillée de manière à présenter une conductivité non nulle. La cavité 26 est délimitée, au moins en regard de la matrice 21 par une paroi 25 épaisse dont la surface extérieure 24 définit, en coopération avec la surface 22 de la matrice 21, la forme de la pièce à obtenir. L'épaisseur de la paroi 25 est déterminée en fonction du matériau du poinçon et des efforts de déformations nécessaires pour former le flan de matière.  In the example shown in Figure 1, the punch 23 comprises a cavity 26 filled with liquid 27. The liquid 27 is generally water, preferably undistilled so as to have a non-zero conductivity. The cavity 26 is delimited, at least opposite the matrix 21 by a thick wall 25 whose outer surface 24 defines, in cooperation with the surface 22 of the matrix 21, the shape of the part to be obtained. The thickness of the wall 25 is determined according to the material of the punch and the deformation forces necessary to form the blank of material.
Préférentiellement, le poinçon 23 comme la matrice 21 sont réalisés en acier allié trempé, présentant une limite élastique de l'ordre de 500 à 1500 MPa.  Preferably, the punch 23 as the die 21 are made of hardened alloy steel, having an elastic limit of the order of 500 to 1500 MPa.
Deux électrodes 28 pénètrent à l'intérieur de la cavité 26 par des traversées isolantes 29 et plongent dans le liquide 27. Les deux électrodes 28 sont reliées à un générateur 17 de forte puissance puisée comprenant une pluralité de condensateurs à haute tension adaptés pour stocker une énergie comprise entre 10 et 100 kJ et un moyen de décharge rapide de ces condensateurs, par exemple un éclateur, aux bornes des électrodes. Lorsque le générateur 17 est déchargé entre les deux électrodes 28, un arc électrique de forte puissance s'établit entre les deux électrodes et vaporise instantanément le liquide 27 au voisinage de l'arc électrique, ce qui permet de générer une onde de pression présentant un très fort gradient de pression, c'est-à-dire une onde de choc, au niveau de l'arc électrique et qui se propage radialement dans toutes les directions. Two electrodes 28 penetrate inside the cavity 26 through insulating bushings 29 and dive into the liquid 27. The two electrodes 28 are connected to a high power pulsed generator 17 comprising a plurality of high voltage capacitors adapted to store a energy between 10 and 100 kJ and a means of rapid discharge of these capacitors, for example a spark gap, across the electrodes. When the generator 17 is discharged between the two electrodes 28, a high power arc is established between the two electrodes and instantaneously vaporizes the liquid 27 in the vicinity of the electric arc, which makes it possible to generate a pressure wave presenting a very strong pressure gradient, that is to say a shock wave, at the level of the arc electric and propagates radially in all directions.
Bien entendu, d'autres configurations d'électrodes sont possibles, comme par exemple utiliser une seule électrode pénétrant dans la cavité par une traversée étanche, la deuxième électrode étant formée par le poinçon lui-même, relié à la masse. Il est également possible d'utiliser un câble coaxial dont une partie est dénudée, la tresse de masse et l'âme du câble formant ainsi des deux électrodes. De plus, dans le cas d'un outillage de grande taille, prévu pour emboutir des pièces de grande dimension, il peut être utile d'installer plusieurs paires d'électrodes en différents points de la cavité et de les coupler soit en série ou en parallèle à un même générateur 17 de puissance appropriée, soit à plusieurs générateurs commandés en synchronisme de manière à générer plusieurs ondes de choc en parallèle pour réaliser une onde de pression résultante couvrant de manière uniforme toute la surface 24 en contact avec le flan de matière 18.  Of course, other configurations of electrodes are possible, such as for example using a single electrode penetrating into the cavity through a sealed passage, the second electrode being formed by the punch itself, connected to ground. It is also possible to use a coaxial cable of which a part is stripped, the ground strap and the core of the cable thus forming two electrodes. In addition, in the case of large tools, intended for stamping large parts, it may be useful to install several pairs of electrodes at different points of the cavity and to couple them either in series or in series. parallel to the same generator 17 of appropriate power, or to several generators controlled in synchronism so as to generate several shock waves in parallel to produce a resulting pressure wave uniformly covering the entire surface 24 in contact with the blank of material 18 .
Les moyens de génération d'une onde de choc peuvent également comprendre un filament métallique connecté entre les deux électrodes 28. Lors de la décharge du générateur 17, le filament, également appelé fil explosible, se vaporise générant un plasma métallique à très haute température. Ce plasma à son tour engendre la vaporisation de l'eau qui l'entoure et génère ainsi une onde de choc. L'outillage peut également comprendre une pluralité de paires d'électrodes reliées, pour au moins certaines d'entre elles, par des fils explosibles de manière à pouvoir générer plusieurs ondes de choc successives sans avoir à intervenir sur l'outillage pour remplacer le fil explosible détruit par la première onde de choc.  The means for generating a shock wave may also comprise a metal filament connected between the two electrodes 28. During the discharge of the generator 17, the filament, also called explosive wire, vaporizes generating a metal plasma at very high temperature. This plasma in turn generates vaporization of the surrounding water and generates a shock wave. The tool may also comprise a plurality of pairs of electrodes connected, for at least some of them, by explosive wires so as to be able to generate several successive shock waves without having to intervene on the tooling to replace the wire explosive destroyed by the first shock wave.
Le poinçon 23 peut comprendre également des conduites 30 d'alimentation / d'évacuation du liquide 27 dans la cavité 26 pour permettre le renouvellement du liquide 27. Les conduites 30 peuvent être munies d'une vanne d'arrêt 31 même si ces vannes d'arrêt ne sont pas absolument nécessaires, le liquide dans la cavité pouvant être mis sous pression par une alimentation permanente, ou même être laissé à pression atmosphérique. The punch 23 may also comprise liquid feed / discharge lines 27 in the cavity 26 to allow the liquid to be renewed. The lines 30 may be provided with a stop valve 31 even if these valves 'stop are not absolutely necessary, the liquid in the cavity can be pressurized by a permanent supply, or even be left at atmospheric pressure.
On se réfère à la figure 2 sur laquelle on a représenté différentes étapes du procédé selon l'invention. À l'étape initiale S 101, les vérins de la presse 10 sont commandés de manière à maintenir l'outillage 20 ouvert, c'est-à-dire que le poinçon 23 et le serre flan 16 sont écartés de la matrice 21. On place alors un flan de matière 18 sur la matrice 21. À l'étape suivante S 102, le vérin secondaire 15 de la presse est actionné de manière à rapprocher le serre flan 16 de la matrice 21 et à maintenir et immobiliser le flan de matière 18 entre le serre flan et la matrice.  Referring to Figure 2 which shows different stages of the method according to the invention. In the initial step S 101, the jacks of the press 10 are controlled so as to keep the tooling 20 open, that is to say that the punch 23 and the blank clamp 16 are spaced from the die 21. then places a blank of material 18 on the die 21. In the next step S 102, the secondary jack 15 of the press is actuated so as to bring the blank clamp 16 of the die 21 and to hold and immobilize the blank of material 18 between the blank and the matrix.
À l'étape S 103, le vérin principal 14 de la presse est actionné de manière à faire descendre le poinçon 23 vers la matrice. Sous l'effet de la pression de déformation P, le flan de matière 18 est déformé entre le poinçon 23 et la matrice 21 pour acquérir la forme finale voulue.  In step S 103, the main ram 14 of the press is actuated to lower the punch 23 to the die. Under the effect of the deformation pressure P, the blank of material 18 is deformed between the punch 23 and the die 21 to acquire the desired final shape.
On maintient alors la pression de déformation P entre le poinçon 23 et la matrice 21 et, à l'étape S 104, on déclenche un arc électrique entre les électrodes 28 de manière à générer une onde de choc symbolisée par les flèches s'éloignant radialement de l'arc électrique.  The deformation pressure P is then maintained between the punch 23 and the die 21 and, in step S 104, an electric arc is triggered between the electrodes 28 so as to generate a shock wave symbolized by the arrows moving radially away from each other. of the electric arc.
À titre d'exemple, l'application d'une énergie de l'ordre de 50 kJ entre les électrodes 28 génère une onde de pression dynamique présentant une amplitude de l'ordre de 500 MPa qui se diffuse dans la cavité 26 jusqu'à rencontrer la face interne de la paroi 25. Cette onde de pression, à quelques pertes près liées aux réflexions sur la face interne de la paroi 25, se communique sous forme d'une contrainte à la paroi 25, puis au flan de matière 18 avant de se diffuser au travers de la matrice 21 vers le bâti 11 de la presse. La contrainte générée dans la paroi 25 du poinçon 23, comme dans le flan de matière 18, par cette onde de pression est de l'ordre de 300 MPa. Cette contrainte est inférieure à la limite élastique du matériau du poinçon, qui est supérieure à 700 MPa, et n'entraîne donc aucune déformation plastique du poinçon dont la forme est conservée. Cependant, pour un flan de matière 18 consistant en un disque d'alliage d'aluminium, par exemple d'aluminium 6061 T4 dont la limite élastique est de l'ordre de 140 MPa, la contrainte de 300 MPa est largement supérieure à la limite élastique. Il s'ensuit une compression plastique du flan de matière 18 selon son épaisseur. Les inventeurs ont alors constaté que cette contrainte en compression, orthogonale à la surface du flan de matière, permettait d'estomper et de relâcher les contraintes parallèles à cette surface, en particulier les contraintes de flexion et de traction, générées par la déformation plastique lors du formage du flan de matière. For example, the application of an energy of the order of 50 kJ between the electrodes 28 generates a dynamic pressure wave having an amplitude of the order of 500 MPa which diffuses in the cavity 26 to to meet the inner face of the wall 25. This pressure wave, with some losses related to the reflections on the inner face of the wall 25, is communicated in the form of a stress to the wall 25, then to the blank of material 18 before to spread through the matrix 21 to the frame 11 of the press. The stress generated in the wall 25 of the punch 23, as in the blank of material 18, by this pressure wave is of the order of 300 MPa. This stress is lower than the elastic limit of the punch material, which is greater than 700 MPa, and therefore does not cause any plastic deformation of the punch whose shape is retained. However, for a blank of material 18 consisting of an aluminum alloy disk, for example example of aluminum 6061 T4 whose elastic limit is of the order of 140 MPa, the stress of 300 MPa is well above the elastic limit. It follows a plastic compression of the blank of material 18 according to its thickness. The inventors then found that this compressive stress, orthogonal to the surface of the blank of material, allowed to fade and relax the stresses parallel to this surface, in particular the bending and tensile stresses, generated by the plastic deformation during forming of the blank of material.
L'étape S 104 peut être répétée plusieurs fois, sans relâcher la pression de déformation P. Les inventeurs ont en effet constaté également que lors de la déformation du flan de matière 18 à l'étape S 103, des déformations parasites telles que des ondulations de faible amplitude à la surface de la pièce formée pouvaient empêcher un contact étroit entre le poinçon 23 et la pièce, dégradant ainsi la transmission de la contrainte orthogonale à la surface de la pièce. L'application des premières ondes de choc lors de la répétition de l'étape S 104 permet d'améliorer le contact entre le poinçon et la pièce, en relâchant les contraintes de surface aux points de contact et en aplanissant ces ondulations. Les ondes de choc suivantes permettent de transmettre la contrainte principalement orthogonale à toute la surface de la pièce.  Step S 104 may be repeated several times, without releasing the deformation pressure P. The inventors have indeed also found that during the deformation of the material blank 18 in step S 103, parasitic deformations such as ripples of small amplitude on the surface of the formed part could prevent close contact between the punch 23 and the workpiece, thereby degrading the transmission of orthogonal stress to the workpiece surface. The application of the first shock waves during the repetition of the step S 104 makes it possible to improve the contact between the punch and the workpiece by releasing the surface stresses at the contact points and by smoothing these corrugations. The following shock waves make it possible to transmit the mainly orthogonal stress to the entire surface of the part.
À titre d'exemple, un flan de matière 18 en aluminium 6061 T4, en forme de disque de 250 mm de diamètre est embouti en forme de cône de 50 mm de profondeur. On mesure le retour élastique sur la profondeur du cône. For example, a blank of material 18 aluminum 6061 T4, disc-shaped 250 mm in diameter is pressed cone-shaped 50 mm deep. The elastic return is measured on the depth of the cone.
On a pu ainsi constater qu'après un emboutissage « conventionnel », c'est-à-dire avant application d'une onde de choc dans l'outillage selon l'invention, le retour élastique est de l'ordre de 1,2 mm soit près de 2,5 %. Après l'application d'une première onde de choc de l'ordre de 300 MPa, le retour élastique diminue à 1 %, passe à 0,6 % à la deuxième onde de choc et après l'application d'une troisième onde de choc, le retour élastique n'est plus que de 0,02 %. It has thus been found that after a "conventional" stamping, that is to say before application of a shock wave in the tool according to the invention, the springback is of the order of 1.2 mm is almost 2.5%. After the application of a first shock wave of the order of 300 MPa, the elastic return decreases to 1%, goes to 0.6% at the second shock wave and after the application of a third wave of shock, the elastic return is only 0.02%.
Il est à noter que grâce à l'outillage selon l'invention, il est possible de répéter l'étape S 104 relativement rapidement, la fréquence de répétition n'étant conditionnée que par la recharge du générateur 17. Il n'est pas non plus nécessaire de prévoir, entre chaque répétition de l'étape S 104, de manipulation de la pièce, celle-ci restant dans l'outillage 20. It should be noted that thanks to the tooling according to the invention, it is possible to repeat the step S 104 relatively quickly, the repetition frequency being conditioned only by the recharging of the generator 17. It is not no more necessary to provide, between each repetition of step S 104, handling of the workpiece, the latter remaining in the tooling 20.
La répétition de l'étape S 104 étant susceptible de polluer le liquide 27, il peut être prévu de changer celui-ci soit l'issue d'un certain nombre de répétitions, soit en ménageant une circulation permanente de liquide entre les conduites 30.  Since the repetition of step S 104 is liable to pollute the liquid 27, it can be provided to change it either after a certain number of repetitions or by providing a permanent circulation of liquid between the pipes 30.
Après application d'un nombre d'ondes de choc correspondant à la précision désirée et à la matière employée pour le flan de matière 18, on passe à l'étape S 105 dans laquelle les vérins 14 et 15 sont actionnés de manière à relever le poinçon 23 et le serre flan 16. Il est alors possible de dégager la pièce formée, qui ne présente pratiquement plus de retour élastique.  After applying a number of shock waves corresponding to the desired accuracy and the material used for the material blank 18, step S 105 in which the cylinders 14 and 15 are actuated to raise the punch 23 and the blank clamp 16. It is then possible to clear the formed part, which has practically no springback.
La presse 10 est une presse hydraulique conventionnelle, du type presse à colonnes dans l'exemple décrit, à laquelle ont été rajoutés le générateur 17 de haute puissance puisée et, le cas échéant, un circuit d'alimentation pour le liquide 27. Il est ainsi possible d'utiliser un atelier d'emboutissage existant sans modification majeure des machines pour la mise en œuvre du procédé de formage selon l'invention.  The press 10 is a conventional hydraulic press, of the column press type in the example described, to which the pulsed high power generator 17 has been added and, if appropriate, a supply circuit for the liquid 27. thus possible to use an existing stamping workshop without major modification of the machines for the implementation of the forming process according to the invention.
Bien entendu, cette description est donnée à titre d'exemple illustratif uniquement et on pourra y apporter de nombreuses modifications sans sortir de la portée de l'invention, comme par exemple utiliser toutes sortes de presse, à col de cygne ou autre. Par ailleurs, la partie de l'outillage de formage comportant la cavité 26 n'est pas nécessairement le poinçon 23 mais pourrait être de manière symétrique la matrice 21. On pourra également, réaliser les étapes d'emboutissage conventionnel au moyen d'un ou plusieurs poinçon(s) conventionnel(s) et n'utiliser le poinçon 23 comportant la cavité 26 que lors de la dernière passe d'emboutissage ou après cette dernière passe. Il sera cependant nécessaire de contraindre de nouveau la pièce 18 avant de générer l'onde de choc.  Of course, this description is given as an illustrative example only and many modifications can be made without departing from the scope of the invention, such as using all kinds of press, gooseneck or other. Furthermore, the part of the forming tool comprising the cavity 26 is not necessarily the punch 23 but could be symmetrically the matrix 21. It will also be possible to perform the conventional stamping steps by means of one or several conventional punch (s) and use the punch 23 having the cavity 26 that during the last stamping pass or after the latter passes. However, it will be necessary to reinforce the piece 18 before generating the shock wave.

Claims

REVENDICATIONS
1/ - Procédé de formage d'une pièce par déformation plastique dans lequel :  1 / - Method of forming a workpiece by plastic deformation in which:
a) on utilise une presse (10) munie d'un outillage (20) comportant une première partie (21) de formage et une deuxième partie (23) de formage, chaque partie de formage comportant une face (22 ; 24) en regard de l'autre partie présentant une forme externe complémentaire d'une forme de pièce à obtenir,  a) using a press (10) provided with a tool (20) comprising a first forming part (21) and a second forming part (23), each forming part comprising a face (22; the other part having a complementary external shape of a piece shape to be obtained,
b) on insère un flan de matière (18) entre la première et la deuxième partie de formage,  b) inserting a blank of material (18) between the first and second forming portions,
c) on actionne la presse de manière à exercer une pression, dite pression de déformation (P), propre à déformer le flan de matière entre la première et la deuxième partie de formage,  c) the press is actuated so as to exert a pressure, called the deformation pressure (P), capable of deforming the blank of material between the first and the second forming part,
caractérisé en ce que l'une au moins des parties (21 ; 23) de formage de l'outillage (20) utilisé comporte une cavité (26) remplie d'un liquide (27) et munie de moyens (28) propres à générer au moins une onde de choc dans la cavité et au travers d'une paroi (25) de ladite partie de formage, ladite paroi étant adaptée pour être sensiblement indéformable sous la pression de déformation et pour présenter une limite élastique supérieure à une contrainte générée par l'onde de choc dans la paroi, characterized in that at least one of the forming portions (21; 23) of the tooling (20) used comprises a cavity (26) filled with a liquid (27) and provided with means (28) suitable for generating at least one shock wave in the cavity and through a wall (25) of said forming part, said wall being adapted to be substantially indeformable under the deformation pressure and to have a yield strength greater than a stress generated by the shock wave in the wall,
et en ce que : and in that :
d) on maintient la pression de déformation entre les parties de formage après déformation du flan de matière,  d) maintaining the deformation pressure between the forming parts after deformation of the blank of material,
e) on génère dans la cavité au moins une onde de choc de telle sorte que l'onde de choc traverse le flan de matière (18) sensiblement orthogonalement à sa surface,  e) generating in the cavity at least one shock wave so that the shock wave passes through the blank of material (18) substantially orthogonal to its surface,
f) on relâche la pression de déformation du flan de matière et on éjecte celui-ci.  f) releasing the deformation pressure of the material blank and ejecting it.
21 - Procédé selon la revendication 1, caractérisé en ce qu'on génère l'onde de choc au moyen d'un arc électrique déclenché entre deux électrodes (28) pénétrant dans la cavité (26). 3/ - Procédé selon la revendication 2, caractérisé en ce que l'arc électrique est obtenu par une impulsion de courant d'une énergie comprise entre 10 kJ et 100 kJ. 21 - Method according to claim 1, characterized in that generates the shock wave by means of an electric arc triggered between two electrodes (28) penetrating into the cavity (26). 3 / - Method according to claim 2, characterized in that the electric arc is obtained by a current pulse with an energy of between 10 kJ and 100 kJ.
4/ - Procédé selon l'une des revendications 1 à 3, caractérisé en ce qu'on génère séquentiellement une pluralité d'ondes de choc, préférentiellement de deux à quatre ondes de choc, sans relâcher la pression de déformation.  4 / - Method according to one of claims 1 to 3, characterized in that sequentially generates a plurality of shock waves, preferably two to four shock waves, without releasing the deformation pressure.
5/ - Outillage (20) de formage d'une pièce par déformation plastique, comportant une première partie (21) de formage et une deuxième partie (23) de formage, chaque partie de formage comportant une face (22 ; 24) en regard de l'autre partie présentant une forme externe complémentaire de la forme à obtenir sur la pièce, caractérisé en ce que l'une au moins des parties (21 ; 23) de formage comporte une cavité (26) remplie d'un liquide (27) et munie de moyens (28) propres à générer au moins une onde de choc dans la cavité et au travers d'une paroi (25) de ladite partie de formage, ladite paroi étant adaptée pour être sensiblement indéformable sous une pression de déformation (P) appliquée entre les parties de formage et pour présenter une limite élastique supérieure à une contrainte générée par l'onde de choc.  5 / - Tooling (20) for forming a workpiece by plastic deformation, comprising a first forming part (21) and a second forming part (23), each forming part comprising a face (22; the other part having an external shape complementary to the shape to be obtained on the part, characterized in that at least one of the forming parts (21; 23) comprises a cavity (26) filled with a liquid (27). ) and provided with means (28) capable of generating at least one shock wave in the cavity and through a wall (25) of said forming part, said wall being adapted to be substantially indeformable under a deformation pressure ( P) applied between the forming parts and to exhibit an elastic limit greater than a stress generated by the shock wave.
6/ - Outillage selon la revendication 5, caractérisé en ce que les moyens de génération d'une onde de choc comprennent au moins une électrode (28) plongeant dans la cavité (26) et reliée à un générateur (17) de forte puissance puisée, adapté pour fournir une impulsion de courant d'une énergie comprise entre 10 kJ et 100 kJ.  6 / - Tooling according to claim 5, characterized in that the means for generating a shock wave comprise at least one electrode (28) immersed in the cavity (26) and connected to a generator (17) of high power pulsed , adapted to provide a current pulse with an energy of between 10 kJ and 100 kJ.
Il - Outillage selon la revendication 6, caractérisé en ce qu'il comporte au moins une paire d'électrodes (28) traversant la paroi de la cavité (26) par des traversées (29) isolantes.  Il - Tooling according to claim 6, characterized in that it comprises at least one pair of electrodes (28) through the wall of the cavity (26) through insulating bushings (29).
8/ - Outillage selon la revendication 7, caractérisé en ce que les électrodes (28) d'au moins une paire d'électrodes sont reliées par un fil métallique adapté pour être vaporisé lors de l'application de l'impulsion de courant. 91 - Outillage selon l'une des revendications 5 à 8, caractérisé en ce que la partie (23) de formage comportant la cavité (26) comporte des moyens (30 ; 31) de renouvellement du liquide (27) à l'intérieur de celle-ci. 8 / - Tooling according to claim 7, characterized in that the electrodes (28) of at least one pair of electrodes are connected by a metal wire adapted to be vaporized during the application of the current pulse. 91 - Tooling according to one of claims 5 to 8, characterized in that the forming portion (23) comprising the cavity (26) comprises means (30; 31) for the renewal of the liquid (27) inside the it.
10/ - Presse d'emboutissage caractérisée en ce qu'elle est munie d'un outillage selon l'une quelconque des revendications 5 à 9.  10 / - Press stamping characterized in that it is equipped with a tool according to any one of claims 5 to 9.
EP14700188.7A 2013-01-11 2014-01-09 Method, tool and press for the electrohydraulic forming of a workpiece Active EP2943297B1 (en)

Applications Claiming Priority (2)

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FR1350270A FR3000909B1 (en) 2013-01-11 2013-01-11 METHOD, TOOLING AND PRESS FOR FORMING A PIECE
PCT/EP2014/050318 WO2014108468A1 (en) 2013-01-11 2014-01-09 Method, tool and press for the electrohydraulic forming of a workpiece

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Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106077225B (en) * 2016-06-22 2018-05-29 北京航空航天大学 A kind of swollen shape-calibration machine of liquid of U-shaped bulkhead class aviation thin-walled workpiece deformation
FR3054968B1 (en) * 2016-08-09 2019-01-25 Adm28 S.Ar.L TOOL, DEVICE AND METHOD FOR INDIRECT ELECTROHYDRAULIC FORMING
FR3058654B1 (en) 2016-11-15 2019-06-07 Adm28 S.Ar.L ELECTROHYDRAULIC FORMING METHOD AND DEVICE THEREOF
FR3062586B1 (en) * 2017-02-08 2020-02-28 Adm28 S.Ar.L ELECTROHYDROFORMING DEVICE
DE102018008672B4 (en) * 2018-11-05 2021-02-11 Max Simmel Maschinenbau GmbH Tool concept and process for partial and incremental forming by electro-hydraulic forming
CN110000283A (en) * 2018-11-09 2019-07-12 南京航空航天大学 A kind of small round corner box part accurate forming method and its forming device
FR3092504B1 (en) * 2019-02-13 2021-01-22 Adm28 S Ar L Hybrid forming process and corresponding forming device
CN113002038B (en) * 2019-12-19 2023-04-07 倍科有限公司 Press device and press method
KR20220056446A (en) 2020-10-28 2022-05-06 주식회사 엘지에너지솔루션 Molding Device of Battery Case Using Shock wave and Molding Method of Battery Case Using Thereof
CN114713702B (en) * 2022-03-24 2023-05-30 华中科技大学 Electric explosion-based metal processing workpiece orthopedic processing device and method

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3267710A (en) * 1962-09-24 1966-08-23 Inoue Kiyoshi Impulsive shaping and bonding of metals and other materials
JPS498992B1 (en) * 1966-12-09 1974-03-01
SU646511A1 (en) * 1977-06-13 1981-08-07 Кировский Политехнический Институт Device for initiating high-voltage discharge
DE19939504A1 (en) * 1999-08-20 2001-03-08 Konrad Schnupp Process for operating a forming press
DE10347601B4 (en) * 2003-10-14 2011-01-27 Benteler Automobiltechnik Gmbh Apparatus and method for hydraulic high pressure forming of a circuit board
US7827838B2 (en) * 2008-05-05 2010-11-09 Ford Global Technologies, Llc Pulsed electro-hydraulic calibration of stamped panels
US7802457B2 (en) * 2008-05-05 2010-09-28 Ford Global Technologies, Llc Electrohydraulic forming tool and method of forming sheet metal blank with the same
EP2292343B1 (en) 2009-09-04 2012-09-19 Reinhold Thewes Device for electrohydraulic sheet metal forming
US8534106B2 (en) * 2009-10-19 2013-09-17 Ford Global Technologies, Llc Hydromechanical drawing process and machine
US8844331B2 (en) * 2010-10-29 2014-09-30 Ford Global Technologies, Llc Electro-hydraulic forming process with electrodes that advance within a fluid chamber toward a workpiece
US8966950B2 (en) * 2013-07-17 2015-03-03 Ford Global Technologies, Llc Method of forming an integral grid reinforcement in a part using an electro-hydraulic forming process

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2014108468A1 *

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CN105026066B (en) 2017-03-22
FR3000909A1 (en) 2014-07-18
CN105026066A (en) 2015-11-04
EP2943297B1 (en) 2016-12-21
JP6258351B2 (en) 2018-01-10
US20150360275A1 (en) 2015-12-17
FR3000909B1 (en) 2015-05-15
JP2016502934A (en) 2016-02-01
WO2014108468A1 (en) 2014-07-17
US10201843B2 (en) 2019-02-12

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