CN111511479A

CN111511479A - Apparatus for incremental stamping by magnetic forming and associated method

Info

Publication number: CN111511479A
Application number: CN201880078137.5A
Authority: CN
Inventors: 吉勒·阿弗里劳德
Original assignee: ADM28 SARL
Current assignee: ADM28 SARL
Priority date: 2017-12-07
Filing date: 2018-12-06
Publication date: 2020-08-07
Also published as: WO2019110760A1; EP3720625A1; FR3074704A1; FR3074704B1; US20210187578A1; JP2021505400A

Abstract

The invention relates to a device for stamping blanks (50) to produce stamped parts. The apparatus comprises a punch (40) comprising a support surface (41), an anvil (70), a die (80) and means (60) for generating a magnetic field. The device is disposed in the punch flush with the support surface. In an initial position, the apparatus is configured such that: -the support surface of the punch receives a portion of the first face of the blank, -the anvil and the device are placed on both sides of the same portion of the blank, the device (60) being opposite the first face (51), the anvil (70) being opposite the second face (52) of the blank at a distance therefrom, -the die (80) being opposite the second face (52), flush with another portion of the blank. The device is configured to apply pressure to the blank in the direction Z' Z in the direction of the anvil. The apparatus comprises first means (43) for moving the punch in the direction Z' Z, and second means (72) for moving the anvil in the same direction.

Description

Apparatus for incremental stamping by magnetic forming and associated method

Technical Field

The invention belongs to the field of forming, and particularly relates to the field of stamping.

The invention relates to a device and a method for producing a stamped part, in particular a part called deep-drawn part, by magnetic pulse stamping of a blank.

Background

In the field of forming, especially metal forming, stamping is a frequently chosen method because it is robust and well mastered.

Stamping is commonly used in industry, especially in the automotive industry, in particular for forming trim panels, such as motor vehicle hoods or doors, due to the high permissible productivity.

Stamping is a forming method which involves obtaining parts with more or less complex shapes by plastic deformation of a blank under pressure.

The punching apparatus for carrying out this method essentially comprises a die and a punch with an almost complementary shape, between which the blank is located. The shape is obtained by driving the blank into the die under the action of the punch. The movement of the blank is typically controlled by a blank holder, which exerts a holding pressure thereon, in order to reduce wrinkles or cracks appearing on the final stamped part.

However, in the presence of parts that are difficult to form (in particular deep drawn parts), the choice of the clamping force to be exerted on the blank holder proves to be difficult. If the force of the blank holder is too great, the wrinkles are removed, but the risk of cracks is high. If the blank holder force is too low, the risk of wrinkles is high.

For producing deep-drawn parts, alternatives to the stamping process are known.

Among these, mention may be made of hydroforming methods. In this method, the blank is formed by the action of a pressurized fluid.

An associated hydroforming apparatus comprises a two-part sealed closed housing including a hollow die having a recess complementary to the shape of the part desired to be obtained. The blank is placed inside the housing. Hydraulic pressure is applied to the blank, pressing it against the recesses of the die. This quasi-static forming method has the major advantage of eliminating punching and the production of complex shapes (in particular undercuts). However, high pressure is essential for forming, which often requires large tonnage presses for larger parts. Therefore, this method is mainly used for forming tubular parts. One of the disadvantages of this method is the cycle time, which is typically several tens of seconds, due to the filling and pressing time.

Among the existing hydroforming methods, mention may be made of the electrohydraulic forming method, known as the EHF method, which is in turn a high-speed deformation method. This method has many advantages, particularly a significant reduction in elastic recovery and increased metal formability. However, the main disadvantages are the need to bring the parts to be formed into contact with water (which may corrode and require drying) and water management.

Mention may also be made of thermoforming processes, such as the superplastic forming process known as SPF process. This approach is based on the ability of some alloys (e.g., titanium) to withstand significant deformation. These alloys (hereinafter superplastic alloys) can reach elongations sometimes exceeding 1000% under certain conditions of temperature, pressure and deformation, whereas conventional alloys generally deform only within a typical range of a few% to 50%.

An associated SPF forming apparatus comprises a sealed closed housing formed in two parts, the housing comprising a hollow mould having a recess complementary to the final external geometry of the part desired to be obtained. The blank is placed inside the housing and held fixedly between the two parts. Pressurized gas is injected into the housing and presses the blank against the recess while deforming the blank. The pressure and temperature of the titanium alloy must be perfectly controlled at about 900 ℃.

Significant disadvantages associated with such SPF forming apparatuses and associated methods are cycle time, cost, and the fact that only certain materials can be used.

Disclosure of Invention

The object of the present invention is to overcome all or part of the limitations of the solutions of the prior art, in particular those set forth above, by proposing, inter alia, solutions that allow to obtain a stamped part, in particular a deep-drawn part.

To this end, the invention is first directed to an apparatus for stamping blanks to produce stamped parts, the apparatus comprising:

-a punch comprising a bearing surface,

-an anvil for placing the anvil in the closed position,

-a die for pressing the metal sheet,

-a magnetic field generating means arranged in the punch at the bearing surface.

The term blank refers to a sheet, in particular a sheet made of a metallic material. A plate is said to be thin when one of its dimensions is significantly smaller than the other two (typically at least on the order of magnitude).

In the initial position, that is to say before the stamping phase, the stamping apparatus is configured such that:

the support surface of the punch is intended for receiving a portion of the first face of the blank,

the anvil and the magnetic field generating means are intended to be arranged on both sides of the same portion of the blank.

The magnetic field generating device faces the first surface. The anvil faces a second face of the blank opposite the first face at a distance from the second face. The die is intended to be arranged facing the second face at another part of the blank.

The magnetic field generating means are intended and configured to apply a pressure to the blank in the direction of the anvil, in the direction Z' Z.

The punching device comprises first displacement means arranged to displace the punch in a direction Z' Z with respect to the die. The punch is advantageously displaced in a translatory manner.

The stamping device comprises second displacement means arranged to displace the anvil relative to the die in the direction Z' Z.

The punch, the anvil and the die are preferably made of a metal material to withstand the high pressure generated by the magnetic field generating means.

The punching apparatus according to the present invention is different from the conventional punching apparatus in that punching is not performed by the punch itself but by the magnetic field generating means.

Similarly, the magnetic field generating device is used differently from the conventional frame of the magnetic forming method that forms the entire blank at once. The magnetic field generating means is arranged to generate a magnetic pulse on only a portion of the blank. The relative displacement of the punch with respect to the generating means allows the displacement of the area of the blank to be affected by the magnetic pulse.

Such a device therefore advantageously allows working at high rates of expansion deformation with the advantages that magnetic forming can bring, such as obtaining radii of curvature of less than 2 mm, fine imprint or close tolerances, and avoiding material cracking or crazing in areas with high elongation, especially for aluminium.

Such a punching device is therefore particularly suitable for producing punched parts, in particular deep-punched parts, without cracks occurring in the parts.

It is also suitable for making the flanging edge with the above-mentioned advantages of magnetic forming.

According to a preferred embodiment, the invention also satisfies the following features, which are implemented individually or in each of their technical operational combinations.

According to a preferred embodiment, the first displacement means comprises a linear actuator.

According to a preferred embodiment, in order to obtain a good efficiency of the method, the magnetic field generating means are in the form of a flat coil, for example in the form of a spiral. The coil is arranged substantially in a plane parallel to the support surface of the punch.

According to a preferred embodiment, the stamping apparatus comprises a blank holder configured to hold another portion of the blank against the die to apply a holding pressure to the movement of the blank against the die so as to limit the formation of wrinkles.

The invention also relates to a method for stamping a blank by magnetic pulses to produce a stamped part by a stamping device according to at least one of its embodiments. The method comprises the following steps:

a) the blank is positioned in the stamping device,

b) subjecting the blank to the magnetic field generated by the magnetic field generating means, so that a pressure is exerted in direction Z' Z on the first face of the blank, pressing the blank against the anvil,

c) the punch is displaced in the direction Z' Z relative to the die by first displacement means, and the anvil is displaced in this direction relative to the die by second displacement means,

preferably, steps b) and c) are repeated in a synchronized manner until the desired shape of the final stamped part is obtained.

Synchronization means that these steps are either performed consecutively one after the other or simultaneously.

When the punch is displaced, a magnetic pulse is generated by the magnetic field generating means, which on the one hand exerts an axial pressure on the blank in the direction of the anvil, pressing the blank against the anvil, and on the other hand exerts a radial pressure on the blank in the direction of the die, pressing the blank against the die.

Advantageously, such a double axial and radial pressure allows the blank to be deformed, avoiding the risk of cracks in the part to be obtained, with excellent forming precision.

Drawings

The invention will be better understood from reading the following description, given by way of non-limiting example and with reference to the accompanying drawings, which illustrate:

fig. 1 to 4, schematic cross-sectional views of an embodiment of a stamping device according to the invention, showing successive steps of stamping a blank,

fig. 5, equivalent to the schematic view of fig. 1, shows a particular embodiment of the punching device with blank holder.

In the drawings, like reference numerals designate identical or similar elements from one figure to another. For clarity, elements shown are not to scale unless otherwise indicated.

Detailed Description

As illustrated in fig. 1 to 4, the stamping device 10 is intended for stamping blanks 50 in order to produce stamped parts, in particular deep-drawn parts.

In an exemplary embodiment, the blank 50 is made of a metallic material (e.g., steel).

The blank 50 has a first face 51 and a second face 52 opposite the first face.

In a preferred non-limiting exemplary embodiment of the invention, a stamping apparatus 10 as shown in cross-section in fig. 1 to 4 is suitable for producing a barrel. Barrel refers to a stamped part having a hollow cylindrical shape with or without a flanged edge.

Those skilled in the art will readily appreciate that the teachings of the present invention may be transferred to other embodiments.

In this specification, for simplicity, terms such as up, down, high, low, left, right, and the like are used with reference to the orientation of each element presented in fig. 1-4. However, unless otherwise specified, these terms merely characterize the relative arrangement of these elements after a possible hypothetical rotation with respect to the effective orientation of the components in space.

The press apparatus 10 includes a first frame 20 and a second frame 30. The first frame 20 may be a lower portion of the stamping apparatus and the second frame 30 may be an upper portion, as illustrated. Alternatively and without departing from the scope of the invention, the first frame 20 may be an upper, left or right part of the stamping device and the second frame 30 may be a lower, right or left part, respectively.

First frame

The first frame 20 is in the form of a first hollow body delimiting a first open cavity 23, preferably in the centre.

In a particular embodiment, the first open cavity 23 has a cylindrical shape, preferably with a circular cross-section.

As illustrated in fig. 1 to 4, the first hollow body is formed by a lower portion 21 and a side portion 22, the inner wall 221 of which delimits a first open cavity 23.

A punch 40 is disposed in the first open cavity 23.

In the particular example where the desired final stamped part is a barrel, the punch 40 is in the shape of a cylindrical body, preferably having a circular cross-section and having a longitudinal axis Z' Z.

In the example of fig. 1 to 4, the longitudinal axis of the punch 40 is a vertical axis, which preferably coincides with the longitudinal axis of the first open cavity 23.

The punch 40 is preferably solid and made of a material, such as a metal material, capable of withstanding the high pressure generated by the magnetic field generating means.

The punch comprises a bearing surface 41 and a side surface 42. The support surface 41 is intended to receive a portion of the blank to be stamped. The side surface 42 is intended to face the inner wall 221 of the side portion 22 of the first hollow body when the punch is positioned in the first open cavity 23.

The punch 40 is movable in the first open cavity 23. The punch 40 is movable in translation along its longitudinal axis Z' Z between two positions:

a retracted position in which the punch is located in the first open cavity 23, an

A deployed position in which the punch is outside the first open cavity 23.

The punch 40 is displaced in the direction Z' Z to its deployed position. The punch 40 is displaced in the direction ZZ' towards its retracted position.

In the example of fig. 4, the punch 40 is shown in the deployed position.

The first displacement device 43 is configured to displace the punch 40 between the retracted position and the deployed position. The first displacement means 43 are actuated manually or automatically.

In an exemplary embodiment, the first displacement means 43 comprises at least one linear hydraulic or pneumatic actuator, such as a cylinder operating between the first frame 20 and the punch 40. In this exemplary embodiment, preferably, a fixed portion (e.g., a cylinder body) of the linear actuator is received in a first open cavity 23 formed in the first frame 20. The movable part of the linear actuator (for example a cylinder piston) is able to move out of the first open cavity 23 for deploying the punch 40 in the direction Z 'Z and is able to displace in the direction ZZ' into the first open cavity 23 to return the punch 40 to its retracted position. In a particularly advantageous manner, the control device controls the first device 43 to displace the punch.

In a variant embodiment, the first displacement means 43 are in the form of a support with a thrust screw able to cooperate with the punch 40 to displace it in translation along the longitudinal axis Z' Z.

The punching apparatus 10 further comprises a magnetic field generating device 60.

The magnetic field generating means 60 are arranged inside the punch 40 at the support surface 41 of the punch.

The magnetic field generating device 60 is configured to generate a magnetic field concentrated in a defined space and for a very short period of time, as will be described later.

In a preferred exemplary embodiment, the magnetic field generating means 60 is in the form of a flat coil, for example in the form of a spiral. The flat coil is preferably disposed in a plane substantially parallel to the bearing surface 41 of the punch 40.

The magnetic field generating means 60 preferably form an integral part of the assembly, which further comprises an electrical energy storage unit, and one or more switches (not shown).

Electrical energy storage units are configured and intended for storing modest amounts of energy, for example, on the order of several kilojoules to tens of kilojoules (kJ).

In a preferred exemplary embodiment, the storage unit is a battery with a discharge capacitor.

Second frame

The second frame 30 is in the form of a second hollow body defining a second open cavity 33.

In a particular embodiment, the second open cavity 33 has a cylindrical shape, preferably with a circular cross-section.

As illustrated in fig. 1 to 4, the second hollow body is formed by an upper portion 31 and a side portion 32, the inner wall 321 of which delimits a second open cavity 33.

The second frame 30 is arranged with respect to the first frame 20 such that the second open cavity 33 is intended for receiving the punch 40 when it is moved in the direction Z 'Z along its longitudinal axis Z' Z to its deployed position. The free end 322 of the side portion 32 of the hollow body of the second frame 30 substantially faces the free end 222 of the side portion 22 of the first hollow body of the first frame 20.

The second hollow body and the punch 40 have dimensions such that the punch 40 can be freely displaced in translation in the second open cavity 33 and allow the blank 50 to pass through over its thickness between the inner wall 321 of the second open cavity 33 and the side surface 42 of the punch 40.

In a preferred embodiment, the side surface 42 of the punch 40 and the side wall 32 of the second hollow cavity 33 have almost complementary shapes, except for the thickness and the operating clearance of the final punched part.

In a non-limiting exemplary embodiment, when the punch 40 is in the shape of a cylindrical body having a circular cross-section, the second open cavity 33 is cylindrical, having a circular cross-section, with a diameter greater than the outer diameter of the punch.

In the example of fig. 1 to 4 and preferably, the longitudinal axis of the second open cavity 33 coincides with the longitudinal axis of the punch 40.

The stamping apparatus further comprises an anvil 70.

The anvil 70 is received in the second open cavity 33. The anvil is movable in the second open cavity 33. The anvil is movable in translation along the longitudinal axis Z' Z, the second displacement device 72 being configured to displace the anvil 70 in translation in the second open cavity 33.

The second displacement means 72 is manually or automatically actuated.

In an exemplary embodiment, the second displacement device 72 comprises at least one linear hydraulic or pneumatic actuator, such as a cylinder operating between the second frame 20 and the anvil 70. In this exemplary embodiment, preferably, a fixed portion (e.g., a cylinder body) of the linear actuator is received in the second open cavity 33. A movable portion of the linear actuator (e.g., a cylinder piston) is displaceable in the second open cavity 33 to displace the anvil 70 in the second cavity. In a particularly advantageous manner, the control device controls the second displacement device 72 of the anvil 70.

In a variant embodiment, the second displacement means 72 are in the form of a support with a thrust screw able to cooperate with the anvil 70 to displace the punch in translation along the axis ZZ'.

In the preferred embodiment, the first displacement device 43 and the second displacement device 72 are similar.

The stamping device further comprises a die 80.

The die 80 is provided at the free end 322 of the side portion 32 of the second frame 30. The free ends 322 of the side portions 32 of the second frame 30 form the lower surface 81 of the die 80.

In a preferred embodiment, the side portion 32 of the second hollow body of the second frame 30 forms a die 80.

The anvil 70 and the die 80 are preferably made of a metallic material, such as steel, which has sufficient structural strength to allow it to withstand the high pressures generated by the impact of the blank 50 against the anvil and the die during the stamping method described later.

The punch 40, anvil 70, die 80 and magnetic field generating means 60 are arranged relative to each other such that in the initial position of the stamping apparatus 10 (fig. 1), that is to say before the stamping method is started, the blank 50 is positioned flat between the elements.

More specifically, the punch 40 is positioned so that in its retracted or intermediate position, its bearing surface 41 is intended for receiving a portion of the first face 51 of the blank 50. In the example illustrated in fig. 1, the support surface 41 of the blank is intended for receiving a central portion of the first face 51 of the blank 50. The anvil 70 and the magnetic field generating means 60 are arranged on both sides of the same portion of the blank 50. The magnetic field generating device 60 faces the first face 51 of the blank 50. The lower surface 71 of the anvil 70 faces the second face 52 of the blank 50.

The lower surface 71 of the anvil 70 is disposed opposite the second face 52 of the blank at another portion of the blank 50. In the example illustrated in fig. 1, the lower surface 81 of the die 80 is disposed opposite the second face 52 of the blank at the peripheral portion of the blank 50.

The lower surface 71 of the anvil 70 is arranged at a distance from the second face 52 of the blank 50.

Preferably, as illustrated in fig. 1, the magnetic field generating device 60 positioned is therefore able and intended to apply pressure to the blank 50 in the direction Z' Z, mainly in the direction of the lower surface 71 of the anvil 70.

In one embodiment shown in fig. 5, the stamping apparatus 10 includes a blank holder 90. The blank holder 90 is accommodated between the free ends 222, 322 of the

side portions

22, 32 of the first and second hollow bodies. The blank holder is configured such that when the blank is in place on the punch 40, the blank is compressed between the blank holder and the die at the free end 322 of the side portion 32 of the second hollow body. By preventing or limiting the formation of wrinkles, the adjustment of the force of the blank holder and/or the gap between the blank holder and the die will regulate the swallowing (i' avalment) of the blank during its forming.

In an exemplary embodiment, the blank holder 90 is held against the free end 322 of the side portion 32 of the second frame 30 by a compression device (e.g., a gas spring).

An example of the punching method is now described.

The blank 50 is intended to conform to the shape of the lower surface 71 of the anvil 70 and to the inner wall 321 of the side portion 32 of the second frame 30 to form a barrel-type deep drawing. The resulting barrel may or may not include a flanging edge.

In a preceding step, the blank 50 is cut from a sheet into the desired dimensions (length and width, or diameter, and thickness).

In a first step, referred to as step a), the blank 50 is positioned in the stamping device 10.

A blank 50 having a substantially flat shape is positioned between the first frame 20 and the second frame 30, as illustrated in fig. 1.

In one embodiment, the blank 50 is provided on the punch 40 on the one hand at its central portion. The blank 50 is arranged so that its first face 51 abuts the support surface 41 of the punch.

The blank 50 is arranged such that its second face 52 faces the lower face 71 of the anvil 70. The lower surface 71 of the anvil 70 is positioned at a distance e from the second face 52 of the blank 50.

The distance e defines the depth at which the deformation of the billet is desired at each discharge (dcharge) (as described below). The distance e is maximized in order to reduce the number of discharges and, therefore, the forming time.

On the other hand, the blank 50 is disposed at its peripheral portion between the lower surface 81 of the die 80 (and therefore the free end 322 of the side portion 32 of the second frame 30 i) and the free end 222 of the side portion 22 of the first frame 20. The second side 52 of the blank 50 is arranged to face the die 80 at a distance therefrom. The first face 51 of the blank 50 is arranged to face the free end 222 of the side portion 22 of the first frame 20.

In an exemplary embodiment, when the blank 50 is placed on the punch 40, the punch is displaced in translation in the direction Z' Z from its retracted position to offset the blank 50 so that, at the peripheral portion of the blank, the second face 52 of the blank is placed in the immediate vicinity (for example in the order of millimetres) of the free end 322 of the side portion 32 of the second frame 30, and therefore in the immediate vicinity of the lower face 81 of the die 80.

When the stamping device 10 comprises blank holders 90, the blank 50 is held against the free ends 322 of the side portions 32 of the second frame 30 by the blank holders.

The method then comprises a second step, called step b), of deforming the blank 50 by magnetic forming.

The central portion of the blank 50 located in the vicinity of the magnetic field generating means 60 is subjected to the magnetic field originating from the magnetic field generating means 60, so that an axial pressure is exerted on the first face 51 of the blank 50 and presses the blank tightly against the lower face 71 of the anvil 70. The arrows illustrated in fig. 2 indicate the direction of the axial pressure applied to the blank 50.

Thus, the blank 50 deforms against the lower surface 71 of the anvil 70.

During this step b) shown in fig. 2, the magnetic field generating means 60 gradually deform the central portion of the blank 50 so as to obtain a first punch having a depth P1 less than the depth P of the final punch sought. The peripheral portion is pressed against the free end 322 of the side portion 32 of the second frame 30 and therefore against the lower surface 81 of the die 80.

The anvil 70 advantageously allows to limit the impact of the discharge on the blank and to avoid cracks thereof.

At the end of this step b), the blank 50 is deformed and has a first punch.

In a third step, referred to as step c), the punch 40 and the anvil 70 are displaced.

The punch 40 is displaced in the direction Z' Z by the first displacement means 43 until the bearing surface 41 of the punch presses against the first face 51 of the blank 50 again, so that the central portion of the blank 50 returns to the immediate vicinity of the magnetic field generating means 60. The peripheral portion of the blank 50 remains at a distance from the die 80 as illustrated in fig. 3.

During step b), the displacement of the punch 40 is performed in the same direction as the direction of displacement of the central portion of the blank 50.

The anvil 70 is displaced in the direction Z' Z by means of a second displacement device 72.

In an exemplary embodiment, the relative displacement of the punch 40 and anvil 70 with respect to the die 80 is performed incrementally, preferably simultaneously.

The displacement of the punch 40 and the displacement of the anvil 70 do not necessarily have to be of the same amount.

The anvil 70 is displaced a sufficient distance in the direction Z' Z to define the desired depth of incremental deformation of the blank.

In an exemplary embodiment, the relative displacement of the punch 40 and anvil 70 is performed continuously. The forming of the blank 50 by the magnetic field generating device 60 may be considered instantaneous with respect to the displacement of the punch 40 and the displacement of the anvil 70. In fact, the duration of the displacement of the punch 40 and of the anvil 70 is generally very slow (of the order of seconds) compared to the duration of the magnetic pulse generated by the magnetic field generating means 60 (of the order of microseconds). In the particular case of this embodiment, the second and third steps are carried out simultaneously, without altering the result of the steps.

In the fourth step, steps b) and c) are sequentially reproduced.

Repeating steps b) and c) until the desired final depth P of the stamped part is obtained.

Upon relative displacement of the punch 40 and the anvil 70 with respect to the die 80, the magnetic field generating means 60 advantageously exerts an axial pressure on the central portion of the blank 50 in the direction of the anvil 70, thereby pressing the central portion of the blank against the anvil. The magnetic field generating means 60 also exert a radial pressure on the blank 50 in the direction of the die 80, against the inner wall 321 of the side portion 32 of the second frame 30, pressing the blank against the inner wall. The horizontal arrows illustrated in fig. 3 and 4 show the direction of the radial pressure exerted on the blank 50. This radial pressure of the blank 50 against the inner wall 321 of the side portion 32 of the second frame 30 advantageously allows the blank to perfectly match the shape of the inner wall.

The number of iterations of steps b) and c) depends, inter alia, on the material from which the blank is made, on the desired depth of the stamped part.

At the end of the stamping process, the blank is converted into a barrel-shaped deep-drawn part with or without flanged edges.

In the example of fig. 4, the bucket is of the bucket type without a flanging rim.

The invention is not limited to the preferred embodiments described above by way of non-limiting example, and the variants mentioned. The invention also relates to variant embodiments within the scope of what the skilled person can envisage.

The above description clearly shows that the invention achieves its own set of objectives through its various features and advantages. In particular, the present invention provides a stamping apparatus suitable for producing stamped parts, in particular deep-stamped parts, without wrinkles or cracks being produced in the parts. Such a stamping apparatus and associated stamping method allow to machine parts at high speed and advantageously deform the blank without the risk of generating cracks in the part desired to be obtained, with excellent forming accuracy.

The invention also advantageously allows the production of a cuff edge.

Claims

1. A blank (50) stamping apparatus (10) for producing stamped parts, the stamping apparatus comprising:

-a punch (40) comprising a bearing surface (41),

-an anvil (70),

-a die (80),

-magnetic field generating means (60) arranged in the punch (40) at the bearing surface (41),

in an initial position, the stamping apparatus is configured such that:

-the support surface (41) of the punch (40) is intended to receive a portion of the first face (51) of the blank (50),

-the anvil (70) and the magnetic field generating means (60) are intended to be arranged on both sides of the same portion of the blank (50),

-the magnetic field generating means (60) face the first face (51) and the anvil (70) faces, at a distance from the second face (52), said second face of the blank (50) opposite to the first face (51),

-the die (80) is intended to be arranged facing the second face (52) at another portion of the blank (50),

said magnetic field generating device (60) being intended and configured to apply a pressure to the blank (50) in a direction Z' Z in the direction of the anvil (70),

the punching apparatus comprises first displacement means (43) arranged to displace the punch (40) relative to the die (80) in the direction Z' Z,

and second displacement means (72) arranged to displace the anvil (70) in a direction Z' Z with respect to the die (80).

2. A stamping apparatus (10) according to claim 1, wherein the first displacement device (43) comprises a linear actuator.

3. Stamping device (10) according to one of the preceding claims, wherein the magnetic field generating means (60) is in the form of a flat coil.

4. The stamping apparatus (10) according to one of the preceding claims, comprising a blank holder (90) configured to hold another portion of the blank (50) against the die.

5. Method for stamping a blank (50) by magnetic pulses to produce a stamped part by a stamping apparatus (10) according to one of claims 1 to 4, the method comprising the steps of:

a) placing the blank (50) in the stamping device (10),

b) subjecting the blank (50) to a magnetic field generated by the magnetic field generating device (60) so as to subject the blank (50) to a pressure in a direction Z' Z on the first face (52) thereof, pressing said blank against the anvil (70),

c) the punch (40) is displaced in a direction Z' Z relative to the anvil (70) by the first displacement means (43) and the die is displaced in the direction relative to the die (80) by the second displacement means (72),

repeating steps b) and c) until the desired shape of the final stamped part is obtained.