Machine and method for stamping metal parts

Abstract

 The invention relates to a stamping machine for metal parts with a plurality of successive die-cutting stations synchronized to shape metal parts from sheet metal coming from a coil of sheet metal supplied to the stamping machine through an inlet provided with inlet rollers for pushing the sheet metal to a first die-cutting station for progressively obtaining successive individualized sheets die-cut according to a predetermined pattern from the sheet metal, characterized in that it comprises
a second die-cutting station (5) for receiving and die-cutting the individualized sheets and comprising a plurality of transfer dies (5a, 5b) arranged one after the other for shaping successive metal parts (3) with a three-dimensional configuration from the successive individualized sheets (1 c) delivered by the first die-cutting station (4), the plurality of transfer dies comprising an initial transfer die (5a) for performing an initial die-cutting of each of the individualized sheets (1c) and obtaining successive initial parts (2a), and a final transfer die (5b) for performing a final die-cutting in each of the previously die-cut parts to obtain the metal parts (3);
an outlet station (6) arranged at the outlet (5c) of the second die-cutting station (5) through which the metal parts (3) shaped in the second die-cutting station (5) are extracted;
a longitudinal advance and retreat device for collecting the individualized sheets (1c) from the first die-cutting station and introducing them in the second die-cutting station (5) and moving the die-cut parts(2a, 2b) towards the outlet station (6) making synchronized stops during the action of each of the transfer dies (5a, 5b) in respective die-cutting positions, and which comprises respective side bars (9a, 9b) which are longitudinally movable in a longitudinal back and forth motion provided with gripping mechanisms comprising gripping clamps (9c, 9d) for gripping respective end portions facing the gripping clamps (9c, 9d), of the individualized sheets and of the successive die-cut parts (2a, 2b) when they are moved by the advance of the side bars (9a, 9b) towards the consecutive transfer dies (5a, 5b).

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention is comprised in the technical field of stamping machines for stamping by means of dies.

BACKGROUND OF THE INVENTION

[0002] The use of two types of different processes for stamping parts is known, the processes known as transfer processes and the processes known as progressive processes.

[0003] In transfer processes, the sheet metal to be die-cut is cut into portions or formats of the size necessary for the part to be obtained. These formats are passed through a series of dies (deep drawing machines, die-cutting machines etc.) which give press strokes to the formats as they pass through each die or station. Between one die and the next, the format or part with the operations performed in the previous station passes to the next station by means of a device which grips the part (generally by means of clamps) and passes it to the next station or die. The gripping device is generally formed by longitudinal stringers arranged along the entire machine which have an advance and retreat (back and forth) movement for collecting the part and passing it to the next station, and a transverse movement for being introduced inside the dies and gripping the parts. The formats thus advance by means of the clamp conveying system from one station to another and are becoming shaped. The excess sheet metal falls to a series of generally lower discharge lines. The operation of the dies and of the transfer conveying system is synchronized.

[0004] In progressive processes, the sheet metal to be die-cut comes from a coil and moves along all the dies or stations continuously, i.e., without pieces or formats corresponding to each part being previously cut. The advance of the sheet metal is performed by means of driving rollers arranged at the inlet of the machine. The sheet metal must furthermore have two planar longitudinal strips robust enough to allow the dragging of the sheet metal. In this case, the parts are shaped when they pass through the successive dies or stations but they remain attached to the common sheet metal until the end. The complete separation of the sheet metal and the machine only occurs at the end of the machine. Between the coil and the driving rollers there is usually a loop acting as a buffer which allows feeding the sheet metal when the rollers cause an advance movement. The advance movement is not continuous in the sense that the sheet metal is moving with a constant speed, but rather it occurs in a discontinuous manner simultaneously to the movement of the dies.

[0005] Depending on the type of part, its size and shape, a transfer process or a progressive process is more convenient. Progressive presses are generally used for small parts since their movement between the successive dies is performed by means of attachments to strips which must be robust enough. In the case of large parts, a very broad strip would be needed.

[0006] Progressive processes are generally suitable for parts with complicated geometries which are distributed in the sheet metal according to a special mapping which allows optimizing the surface of the sheet metal and therefore they do not allow cuts transverse to the sheet metal for establishing unitary formats for each part, since a highly considerable surface of the sheet metal would thus be wasted. Furthermore, if the parts have complex shapes, transfer devices may be little suitable since gripping by means of clamps provided at a side structure which advances longitudinally but which must furthermore enter inside the dies to pick up the part is very complicated, since it can entail a very complex clamp distribution. On the other hand, progressive processes are not very suitable when the parts have bent edges perpendicular to the surface of the sheet metal, since they require much space between parts. Neither are they suitable if holes must be made in these surfaces since the punching dies cannot enter to perform the drilling. Therefore, a problem arises when parts are to be stamped which have large dimensions, with complicated geometries and which have bent edges and holes in these edges, such as, for example, the parts forming part of a support structure of large dimensions, such as those which are used to support photovoltaic panels in solar power plants.

DESCRIPTION OF THE INVENTION

[0007] The object of the present invention is to overcome the drawbacks of prior art detailed above, by means of a machine and method for stamping metal parts.

[0008] According to the invention, the machine for stamping metal parts has a plurality of successive die-cutting stations synchronized to shape metal parts from sheet metal coming from a coil of sheet metal supplied to the stamping machine through an inlet provided with inlet rollers for pushing the sheet metal to a first die-cutting station for progressively obtaining successive individualized sheets die-cut according to a predetermined pattern from the sheet metal, and comprises
a second die-cutting station for receiving and die-cutting the individualized sheets, comprising a plurality of transfer dies arranged one after the other for shaping successive metal parts from the successive individualized sheets delivered by the first die-cutting station, the plurality of transfer dies comprising an initial transfer die for performing an initial die-cutting of each of the individualized sheets and obtaining successive initial parts, and a final transfer die for performing a final die-cutting in each of the previously die-cut parts to obtain the metal parts;
an outlet station arranged at the outlet of the transfer die-cutting station through which the metal parts shaped in the second die-cutting station are extracted;
a longitudinal advance and retreat device for collecting the individualized sheets from the first die-cutting station and introducing them in the second die-cutting station and moving the die-cut parts towards the outlet station making synchronized stops during the action of each of the transfer dies in respective die-cutting positions, and which comprises respective side bars which are longitudinally movable in a longitudinal back and forth motion provided with gripping mechanisms comprising gripping clamps for gripping respective end portions facing the gripping clamps, of the individualized sheets and of the successive die-cut parts when they are moved by the advance of the side bars towards the consecutive transfer dies.

[0009] As can be observed, the first die-cutting station operates similarly to a progressive die-cutting station, although its action does not result in individualized three-dimensional formats but rather in individualized sheets die-cut according to a predetermined pattern. In turn, the second die-cutting station operates like a transfer station, but it does not start from individualized three-dimensional formats or from the same sheet metal, but rather from the individualized sheets which it receives directly from the first die-cutting station.

[0010] Conveniently, between the coil and the inlet rollers there is a loop acting as a buffer which allows feeding the sheet metal when the rollers cause an advance movement. This advance movement is not continuous in the sense that the sheet metal is moving with a constant speed, but rather it occurs in a discontinuous manner simultaneously to the movement of the dies.

[0011] The side bars are preferably connected to a transverse movement mechanism for moving the side bars transversely between a distanced position in which the gripping clamps are distanced from said end portions, and a collecting position in which the clamps can grip said end portions.

[0012] The longitudinal advance and retreat mechanism can be designed to move the side bars at a pace of movement such that, in the second die-cutting station, in the die-cutting positions, the die-cut parts are more distanced from one another than the distance at which the individualized sheet of the sheet metal from which it has been separated in the first die-cutting station is located.

[0013] In an embodiment of the invention, the second die-cutting station comprises at least one deep drawing transfer die for conferring a predetermined three-dimensional structure to each of the successive die-cut parts and at least one punching transfer die for performing punches in the successive die-cut parts. The deep drawing transfer die can be the initial transfer die, whereas the final transfer die can be a punching die.

[0014] The machine can furthermore be provided with a transverse punching device arranged such that it is capable of punching edges bent by the deep drawing transfer die outside the horizontal plane of each of the successive die-cut parts. The transverse punching device can be arranged between a deep drawing transfer die and the outlet station, and can comprise at least one punching carriage movable along the bent edges of the die-cut part to punching positions in said edges.

[0015] The outlet station can comprise an ejecting mechanism for ejecting the metal parts from the second die-cutting station, the ejecting mechanism comprising a holding mechanism comprising respective holding clamps arranged at the ends of the side bars such that they can grip the metal part obtained in the second die-cutting station and extract at least a front portion of the metal part by means of at least one advance movement of the side bars. The ejecting mechanism can be designed to eject the front portion of the metal part in a first advance movement of the side bars and to eject the whole metal part in a second advance movement of the side bars. In turn, the outlet station can comprise a conveyor belt for collecting the extracted metal parts.

[0016] To achieve the synchronization between the operations of the first and second die-cutting station as well as the compliance with the applicable safety regulations, the first station is preferably provided with passage and presence detectors, whereas the second die-cutting station is provided with an electronic control independent from the upward and downward movements of the press which allows accelerating, decelerating and even stopping the advance of the parts in their path towards the outlet station,

[0017] The method for stamping metal parts by using a plurality of successive die-cutting stations synchronized to shape metal parts from sheet metal coming from a coil of sheet metal supplied to the stamping machine through an inlet provided with inlet rollers for pushing the sheet metal to a first die-cutting station for progressively obtaining successive individualized sheets die-cut according to a predetermined pattern from the sheet metal, comprises
transferring the individualized sheets from the progressive die-cutting station directly to a second die-cutting station arranged after the first die-cutting station;
performing, in the second die-cutting station, by means of a plurality of transfer dies arranged one after the other, a transfer die-cutting for shaping successive metal parts from the successive individualized sheets delivered by the first die-cutting station, the transfer die-cutting comprising initial die-cutting in an initial transfer die for performing an initial die-cutting of each of the individualized sheets and obtaining successive initial parts, and a final transfer die-cutting in a final transfer die for performing a final die-cutting in each of the previously die-cut parts to obtain the metal parts;
conveying the individualized sheets towards an outlet station making synchronized stops during the action of each of the transfer dies in respective die-cutting positions, by means of a longitudinal advance and retreat device comprising respective side bars longitudinally movable in a longitudinal back and forth motion provided with gripping mechanisms comprising gripping clamps for gripping respective end portions facing the side clamps of the successive individualized formats and of the successive die-cut parts from the individualized sheets when they are moved in the advance of the side bars towards the consecutive transfer dies;
extracting the metal parts shaped in the second die-cutting station through the outlet of the second die-cutting station by means of the outlet station.

[0018] The method preferably comprises conferring a predetermined three-dimensional structure to the individualized sheets by making them pass through at least one deep drawing transfer die, and performing punches in the successive die-cut parts by means of at least one punching transfer die.

[0019] The method according to the invention can also preferably comprise a step of performing a punching of the edges bent by the deep drawing transfer die outside the horizontal plane of each of the successive die-cut parts by means of at least one transverse punching device arranged between a deep drawing transfer die and a punching transfer die.

[0020] As can be observed, the present invention allows, compared to conventional stamping systems, reducing the work cycle time in the manufacture of metal parts, the elimination of the need to have intermediate stocks, and a substantial energy saving. Thus, for example, in relation to the reduction of the work cycle, a part with dimensions of 3000x600x60 in conventional presses is stamped with a rate of 5 strokes per minute, whereas the present invention allows performing 8 strokes per minute. On the other hand, the elimination of the intermediate stocks means that it is not necessary to convey the parts between processes, which in turn allows eliminating manual interaction and defects in parts due to handling. Finally, the energy saving can amount, for example, to -57% for the press for manufacturing parts of dimensions of 3000x600x60, due to the fact that, with the conventional process, 3 presses of 1000 T are required to produce such parts, whereas such parts can be manufactured with a single press, and with a consumption of 1300 T. The elimination of the need to convey the parts between processes also contributes to the energy saving, all of which in turn allows eliminating the possibility of manual interaction and defects in parts due to handling.

[0021] It is therefore evident that the present invention overcomes the drawbacks of prior art indicated above.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Aspects and embodiments of the invention are described below on the basis of some schematic drawings in which

Figure 1 is a schematic side elevational view of an embodiment of a stamping machine according to the present invention;

Figure 2 is a top plan view of the die-cutting machine;

Figures 3 to 16 show a cycle for shaping a metal part in a machine according to an embodiment of the invention.

[0023] In these figures there are reference numbers identifying the following elements:

1

sheet metal

1a

sheet metal provided with a first die-cutting

1 b

sheet metal provided with a second die-cutting

1c

individualized sheet

2a

initial die-cut part

2b

final die-cut part

3

metal part

3a

front portion of the metal part

4

first die-cutting station

4a

first punch

4b

second punch

4c

third punch

2a, 2b

die-cut parts

4

progressive die-cutting station

5

second die-cutting station

5a

deep drawing transfer die

5b

punching transfer die

5c

outlet of the die-cutting transfer station

6

outlet station

6a, 6b

holding clamps

7

conveyor belt

8a

deep drawing male element

8b

punching male element

9a, 9b

side bars

9c, 9d

gripping clamps

10

transverse punching device

11

inlet rollers

12

support structure

13a

lower portion of the stamping machine

13b

upper portion of the stamping machine

14

inlet to the machine

WAYS TO CARRY OUT THE INVENTION

[0024] In the embodiment shown in Figures 1 and 2, the stamping machine for metal parts comprises two successive die-cutting stations -4, 5, 10- which are synchronized to shape metal parts -3- from sheet metal -1- drawn from a coil of sheet metal (not shown in the figures) and fed to the inlet -14- of the machine through inlet rollers -11-pushing the sheet metal -1- into the first die-cutting station -4-. In the first die-cutting station -4-, the sheet metal -1- is successively die-cut according to predetermined patterns to first obtain the sheet metal provided with a first die-cutting -1a-, then the sheet metal provided with a second die-cutting -1 b- and finally individualized sheets -1c-, each of which is provided with a final predetermined pattern. For this purpose, the sheet metal advances step by step through the first die-cutting station -4- making successive stops below the first punch -4a-, the second punch -4b- and the third punch -4c- assembled in the upper portion -13b- of the stamping machine, such that the downward movement of the punches -4a, 4b, 4c- causes the die-cutting of the sheet metal -1- and, finally, due to the action of the third punch, the individualized sheet -1 c-.

[0025] The second die-cutting station -5- comprises a deep drawing transfer die -5a-for conferring a predetermined three-dimensional structure to each of the successive individualized sheets -1c-, to obtain an initial die-cut part -2a- with edges bent outside its horizontal plane, and a punching transfer die -5b- for performing punches in the successive initial die-cut parts -2a- and obtaining successive final die-cut parts -2b-. To perform punches in the edges bent by the deep drawing transfer die -5a-present in the final die-cut parts -2b-, the stamping machine is furthermore provided with a transverse punching device -10- arranged between the punching transfer die -5b- and the outlet station -6-, and which comprises several punching carriages which are movable along the bent edges of the die-cut part -2b- to punching positions at said edges.

[0026] The stamping machine further comprises a longitudinal advance and retreat device for collecting the individualized sheets -1 c- from the first die-cutting station -4- and introducing them in the second die-cutting station -5-, and moving the die-cut parts-2a, 2b- towards an outlet station -6- making synchronized stops during the action of each of the transfer dies -5a, 5b- in respective die-cutting positions, in which the deep drawing male element -8a- and the deep drawing die -5a,- and the punching male element -8b- and the punching die -5b- act respectively. The advance and retreat device comprises respective side bars -9a, 9b- longitudinally movable in a longitudinal back and forth motion provided with gripping mechanisms comprising gripping clamps -9c, 9d- for gripping respective end portions, facing the gripping clamps -9c, 9d-, of the individualized sheets and of the successive die-cut parts-2a, 2b- when they are moved by the advance of the side bars -9a, 9b- to the consecutive transfer dies -5a, 5b-. The side bars -9a, 9b- are connected to a transverse movement mechanism for moving the side bars -9a, 9b- transversely between a distanced position in which the gripping clamps -9c, 9d- are distanced from said end portions and a collecting position in which the clamps can grip said end portions. The longitudinal advance and retreat mechanism is designed to move the side bars -9a, 9b- at a pace of movement such that in the second die-cutting station -5-, in the die-cutting positions, the die-cut parts -2a, 2b- are more separated from one another than the separation at which the individualized sheet -1 c- of the sheet metal -1- from which it has been separated in the first die-cutting station -4- is located.

[0027] The outlet station -6- through which the metal parts -3- are extracted is arranged at the outlet -5c- of the second die-cutting station -5-, and comprises an ejecting mechanism which comprises a holding mechanism comprising respective holding clamps -6a, 6b- arranged at the ends of the side bars -9a, 9b- such that they are capable of gripping the metal part -3- obtained in the die-cutting station transfer -5- and first extract a front portion of the metal part -3- by means of a first advance movement of the side bars -9a, 9b-, and eject the whole metal part -3- in a second advance movement of the side bars -9a, 9b-. The outlet station -6- further comprises a conveyor belt -7- onto which the extracted metal parts -3- fall and which conveys the metal parts -3- towards, for example, a packaging installation (not shown in the figures).

[0028] The operation of the stamping machine described above with reference to Figures 1 and 2 can be observed in Figures 3 to 16, which show the basic steps of a cycle for shaping a metal part -3- from an individualized sheet -1 c- from the sheet metal -1-. For the sake of simplification, in these figures depiction of the transverse punching device -10- has been omitted.

[0029] In Figure 3 the first phase of the work cycle can be observed, in which the transversely opposite side portions of the individualized metal sheet -1 c- (drawn with a thick solid line) obtained after the first and second die-cutting -1a, 1 b- of the sheet metal -1-, face respective first pairs of clamps -9c, 9d- coupled to the respective side bars -9a, 9b-. When the transverse bars -9a, 9b- move transversely towards one another in the direction of the arrows shown in Figure 3, they reach the position shown in Figure 4 in which the first pairs of gripping clamps -9c, 9d- grip the respective side portions of the individualized sheet -1c-.

[0030] When, from the position shown in Figure 4, the side bars -9a, 9b- advance longitudinally in the direction of the arrows shown in Figure 4, they reach the position shown in Figure 5, in which they have conveyed the individualized sheet -1c- to the deep drawing transfer die -5a-. In this position, the pairs of gripping clamps -9c, 9d- open and the side bars -9a, 9b- move away from the individualized sheet -1 c- in the direction of the arrows shown in Figure 5, the side bars reach the position shown in Figure 6 and, after the action of the deep drawing male element -8a- the initial die-cut part -2a- is shaped. Simultaneously, the side bars -9a, 9b-again retreat in the direction of the arrows shown in Figure 6, and reach the position shown in Figure 7, in which the side portions of the initial part face respective second pairs of clamps -9c, 9d-. From this position, the side bars again move transversely towards the initial die-cut part -2a- in the direction of the arrows shown in Figure 7, reaching the position shown in Figure 8 in which the second pairs of clamps -9c, 9d- grip the side portions of the initial part -2a-.

[0031] The side bars -9a, 9b- then advance again in the direction of the arrows shown in Figure 8, adopting the position shown in Figure 9, in which the initial die-cut part -2a- is positioned in the punching transfer die -5b-, after which the second pairs of gripping clamps -9c, 9d- open and the side bars -9a, 9b again separate and retreat, reaching the position shown in Figure 10. Once the side bars -9a, 9b- are separated, the final die-cut part -2b- is shaped by action of the punching male element -8b-. In turn, as shown in Figure 10, when the side bars -9a, 9b- have retreated, the side portions of the final die-cut part -2b- face respective third pairs of gripping clamps -9c, 9d-.

[0032] Next, the side bars -9a, 9b- again move closer to the final die-cut part -2b- in the direction of the arrows shown in Figure 10, and the third pairs of gripping clamps -9c, 9d-, as shown in Figure 11, grip the side portions of the final die-cut part -2b-then actuating the transverse punching device -10- shown in Figure 2 such that the metal part -3- is formed. After that, the side bars -9a, 9b- again advance in the direction of the arrows shown in Figure 11, until reaching the position shown in Figure 12, in which the front portion -3a- the metal part -3- protrudes from the outlet -5c- of the second die-cutting station -5- and remains positioned in a cantilevered manner on the conveyor belt -7-.

[0033] Then, the clamps -9c, 9d- of the third pair of clamps open and the side bars -9a, 9b- separate in the directions of the arrows shown in Figure 12, such that they reach the position shown in Figure 13, in which the front portion of the metal part -3-is secured by the holding parts -6b-. The side bars -9a, 9b- then retreat again in the direction of the arrows shown in Figure 13, until the position shown in Figure 14, in which the holding clamps -6a- face one of the side portions of the metal part -3-whereas the other front portion -3a- thereof is still secured by the holding clamps -6b-.

[0034] The side bars -9a, 9b- again approach the metal part -3- in the directions of the arrows shown in Figure 14, until reaching the position shown in Figure 15, in which the metal part -3- is secured by the respective pairs of holding clamps -6a, 6b. When the side bars -9a, 9b- then advance again in the direction shown by the arrows shown in Figure 15, reaching the position shown in Figure 16, in which the holding clamps -6b- release the front portion of the metal part -3- and the holding clamps -6a- coupled to the right side bar -9a- leave the metal part -3- ejected from the outlet -5c- of the second die-cutting station -5- such that, when the clamps -6a-open and the side bars again separate in the directions shown by the arrows shown in Figure 16, the metal part -3- is released and falls onto the conveyor belt -7-.

[0035] As evident from Figures 3 to 16 and from the corresponding description of the work cycle made with reference to said figures, the back and forth motion of the side bars -9a, 9b- allows forming at the same time, by means of a single die-cutting stroke simultaneously performed by the punches -4a, 4b, 4c- of the first die-cutting station -4- and the male elements 8a, 8b- of the second die-cutting station -5-, die-cutting the sheet metal -1-, separating an individualized part -1c-, shaping an initial die-cut part -2a-, a final die-cut part -2b- and a metal part -3- which, in the back and forth movement of the side bars -9a, 9b- and the action of the gripping clamps -9c, 9d-, are successively conveyed to the next die-cutting position, such that it is possible to continuously manufacture successive metal parts -3- from the sheet metal -1-, and eject the successively shaped metal parts -3- from the stamping machine.

Claims

1. Stamping machine for metal parts with a plurality of successive die-cutting stations synchronized to shape metal parts from sheet metal coming from a coil of sheet metal supplied to the stamping machine through an inlet provided with inlet rollers for pushing the sheet metal to a first die-cutting station for progressively obtaining successive individualized sheets die-cut according to a predetermined pattern from the sheet metal, characterized in that it comprises
a second die-cutting station (5) for receiving and die-cutting the individualized sheets and comprising a plurality of transfer dies (5a, 5b) arranged one after the other for shaping successive metal parts (3) with a three-dimensional configuration from the successive individualized sheets (1c) delivered by the first die-cutting station (4), the plurality of transfer dies comprising an initial transfer die (5a) for performing an initial die-cutting of each of the individualized sheets (1 c) and obtaining successive initial parts (2a), and a final transfer die (5b) for performing a final die-cutting in each of the previously die-cut parts to obtain the metal parts (3);
an outlet station (6) arranged at the outlet (5c) of the second die-cutting station (5) through which the metal parts (3) shaped in the second die-cutting station (5) are extracted;
a longitudinal advance and retreat device for collecting the individualized sheets (1 c) from the first die-cutting station and introducing them in the second die-cutting station (5) and moving the die-cut parts (2a, 2b) towards the outlet station (6) making synchronized stops during the action of each of the transfer dies (5a, 5b) in respective die-cutting positions, and which comprises respective side bars (9a, 9b) which are longitudinally movable in a longitudinal back and forth motion, provided with gripping mechanisms comprising gripping clamps (9c, 9d) for gripping respective end portions, facing the gripping clamps (9c, 9d), of the individualized sheets and of the successive die-cut parts (2a, 2b) when they are moved by the advance of the side bars (9a, 9b) towards the consecutive transfer dies (5a, 5b).

2. Machine according to claim 1, characterized in that the side bars are connected to a transverse movement mechanism for moving the side bars (9a, 9b) transversely between a distanced position in which the gripping clamps (9c, 9d) are distanced from said end portions, and a collecting position in which the clamps can grip said end portions.

3. Machine according to claim 1 or 2, characterized in that the longitudinal advance and retreat mechanism is designed to move the side bars (9a, 9b) at a pace of movement such that, in the second die-cutting station (5), in the die-cutting positions, the die-cut parts(2a, 2b) are more separated from one another than the separation at which the individualized sheet (1 c) of the sheet metal (1) from which it has been separated in the first die-cutting station (4) is located.

4. Machine according to claim 1, 2 or 3, characterized in that the second die-cutting station (5) comprises at least one deep drawing transfer die (5a) for conferring a predetermined three-dimensional structure to each of the successive die-cut parts (2a, 2b) from the individualized sheet, and at least one punching transfer die (5b) for performing punches in the successive die-cut parts (2b).

5. Machine according to claim 4, characterized in that the deep drawing transfer die (5a) is the initial transfer die.

6. Machine according to claim 4, characterized in that the final transfer die (5b) is a punching die.

7. Machine according to claim 4, characterized in that it comprises at least one transverse punching device (10) arranged such that it is capable of punching edges bent by the deep drawing transfer die (5a) outside the horizontal plane of each of the successive die-cut parts (2b).

8. Machine according to claim 7, characterized in that the transverse punching device (10) is arranged between a deep drawing transfer die (5a) and the outlet station (6).

9. Machine according to claim 7 or 8, characterized in that the transverse punching device (10) comprises at least one punching carriage movable along the bent edges of the die-cut part (2b) to punching positions at said edges.

10. Machine according to any one of the previous claims, characterized in that the outlet station (6) comprises an ejecting mechanism for ejecting the metal parts from the second die-cutting station, the ejecting mechanism comprising a holding mechanism comprising respective holding clamps (6a, 6b) arranged at the ends of the side bars (9a, 9b) such that they can grip the metal part (3) obtained in the die-cutting station transfer (5) and extract at least a front portion of the metal part (3) by means of at least one advance movement of the side bars (9a, 9b).

11. Machine according to claim 10, characterized in that the ejecting mechanism is designed to eject the front portion of the metal part (3) in a first advance movement of the side bars (9a, 9b) and to eject the whole metal part (3) in a second advance movement of the side bars (9a, 9b).

12. Machine according to claim 10 or 11, characterized in that the outlet station (6) comprises a conveyor belt (7) for collecting the extracted metal parts (3).

13. Method for stamping of metal parts by using a plurality of successive die-cutting stations synchronized to shape metal parts from sheet metal coming from a coil of sheet metal supplied to the stamping machine through an inlet provided with inlet rollers for pushing the sheet metal to a first die-cutting station for progressively obtaining successive individualized sheets die-cut according to a predetermined pattern from the sheet metal, characterized in that it comprises
transferring the individualized sheets (1c) from the first die-cutting station (4) directly to a second die-cutting station (5);
performing, in the second die-cutting station by means of a plurality of transfer dies arranged one after the other, a transfer die-cutting for shaping successive metal parts (3) from the successive individualized die-cut formats (1 c) delivered by the first die-cutting station (4), the transfer die-cutting comprising an initial die-cutting in an initial transfer die (5a) for performing an initial die-cutting of each of the individualized sheets (1c) and obtaining successive initial parts (2a), and a final transfer die-cutting in a final transfer die (5b) for performing a final die-cutting in each of the previously die-cut parts (2a, 2b) to obtain the metal parts (3);
conveying the individualized sheets (1 c) towards an outlet station (6) making synchronized stops during the action of each of the transfer dies (5a, 5b) in respective die-cutting positions, by means of a longitudinal advance and retreat device comprising respective side bars (9a, 9b) longitudinally movable in a longitudinal back and forth manner provided with gripping mechanisms comprising gripping clamps (9c, 9d) for gripping respective end portions facing the gripping clamps (9c, 9d) of the successive individualized sheets (1c) and of the successive die-cut parts (2a, 2b) obtained from the individualized sheets (1c) when they are moved by the advance of the side bars (9a, 9b) towards the consecutive transfer dies (5a, 5b);
extracting the metal parts (3) shaped in the second die-cutting station (5) through the outlet (5c) of the second die-cutting station (5) by means of the outlet station (6).

14. Method according to claim 13, characterized in that it comprises conferring a predetermined three-dimensional structure to the successive individualized sheets (1c) by making them pass through at least one deep drawing transfer die (5a), and performing punches in the successive die-cut parts (2b) by means of at least one punching transfer die (5b).

15. Method according to claim 14, characterized in that it comprises punching edges bent by the deep drawing transfer die (5a) outside the horizontal plane of each of the successive die-cut parts(5b) by means of at least one transverse punching device (10) arranged between a deep drawing transfer die (5a) and a punching transfer die (5b).

Drawing