EP3148721A1

EP3148721A1 - Method and facility for progressively transforming a strip of metal material

Info

Publication number: EP3148721A1
Application number: EP15732837.8A
Authority: EP
Inventors: André MAILLARD; Christophe PIAT
Original assignee: Centre Technique des Industries Mecaniques CETIM
Current assignee: Centre Technique des Industries Mecaniques CETIM
Priority date: 2014-06-02
Filing date: 2015-06-02
Publication date: 2017-04-05
Also published as: FR3021565A1; FR3021565B1; WO2015185852A1

Abstract

The invention concerns a method and a facility for progressively transforming a strip of metal material (25). Said method comprises the following steps: Providing a progressive die (12) comprising a plurality of workstations (14, 16, 18, 20, 22, 24); providing a longitudinal strip (25) of a metal material having a series of strip portions (48, 50, 52, 54, 56, 58, 60, 62); and driving said strip (25) through said progressive die (12), at a predefined pitch, while actuating said progressive die (12) at each pitch such that said plurality of workstations (14, 16, 18, 20, 22, 24) simultaneously transforms a plurality of strip portions, Providing heat energy to said strip of metal material (25), upstream from at least one of said workstations of said plurality of workstations (14, 16, 18, 20, 22, 24).

Description

Process and installation for progressive transformation of metal material into web

The present invention relates to a method and an installation for the progressive transformation of metallic material into strips for forming metal parts.

A field of application envisaged is for example that of aluminum parts for the automotive industry, for which it is necessary to obtain such parts at extremely advantageous costs.

The progressive transformation installations comprise a progressive tool, commonly referred to as a "tool to be followed" and it is adapted to be installed in a press in order to be actuated. The progressive tool comprises successive workstations through which a metal material strip, and for example aluminum, will be gradually deformed and / or cut to be able to lead to a finished part.

In particular, reference may be made to document EP0325947, which describes such a type of installation.

The strip of metallic material is sequentially driven within the progressive tool, and at each step the tool is actuated by the press. Also, each time the tool is actuated, all the workstations are activated simultaneously and they cause, each, a transformation of the metal, whether it is stamping, folding, cutting all other operations of implementation. shape of the strip metal material. The tool can be actuated, for example between 40 and 100 times per minute, and the strip of metallic material is driven in translation by a given pitch, at the frequency corresponding to that of the movement of the tool.

Of course, the manufacturing cost of the parts thus obtained depends in part on the speed at which they can be manufactured and hence on the frequency with which the progressive tool can be driven in motion by the press. However, when precisely the production rates are increased, it is observed that the parts are less well formed and that they may have defects, for example, appearance, rupture or still related to the elastic return. Indeed, when the parts have a springback the form originally provided is not respected.

Also, a problem that arises and that aims to solve the present invention is to provide a method and an installation to implement it, to improve the productivity of progressive tools, without the metal parts thus obtained lose their characteristics.

For this purpose, and according to a first aspect, the present invention provides a method of progressively transforming metal material into webs to form metal parts, said method being of the type comprising the following steps: a tool is provided on the one hand progressive actuator having a plurality of work stations successively arranged between a first work station and a last work station; and on the other hand, a longitudinal strip of a metallic material having a succession of strip portions; and sequentially driving said web through said progressive tool from said first workstation to said last workstation at a given pitch while operating said progressive tool at each step to make said plurality of workstations simultaneously causes the transformation of a plurality of strip portions, and so as to progressively form between said first work station and said last work station metal parts. In addition, thermal energy is provided to said strip of metallic material by conduction upstream of at least one of said plurality of workstations.

Thus, a feature of the invention lies in heating the strip of metal material inside the tool before passing through at least one of the workstations. In this way, the metal is here brought to temperature in a controlled manner and has a given temperature value, so as to reduce the temperature rise time of the material and bring it to a desired value, for example 200 ° C. In this way, one can increase the operating rate of the tool to follow, while getting parts without defects, appearance or breakage and not having a springback. This benefits from the positive effect of temperature on the forming of the part and on its geometry. Also, since said thermal energy is supplied to said strip of metallic material by conduction, the rise in temperature of the strip of metallic material is then extremely rapid, compared to other types of heating. Moreover, such a method makes it possible to provide thermal energy at an advantageous cost compared to induction heating. In addition, and preferably, said strip of metal material having two opposite faces, said thermal energy is simultaneously supplied to said two opposite faces. At the same time, the rise in temperature of the strip of metallic material is increased. Thus, thanks to this heat input, the metal material found after stamping, its ductility it tends to lose over successive transformations.

Advantageously, said thermal energy is supplied to at least one portion of the strip. Thus, the thermal energy is supplied to a portion of the strip which, at the next movement of the tool, is transformed into the consecutive work station. Indeed, the thermal energy is provided, advantageously, to the operating frequency of the press. In other words, the strip of metallic material advances in successive steps of equal length, and at each step of advancement, it preferably undergoes a transformation or it receives thermal energy. Of course, the thermal energy can be provided simultaneously to two or more strip portions, spaced apart from each other, prior to their respective passage in the next work station.

In addition, according to a particularly advantageous embodiment, said strip is compressed between two heating elements. In this way, the strip of metallic material is maintained in a confined space, thereby promoting its rise in temperature, while avoiding heat losses.

According to a second aspect, the present invention proposes an installation for progressively transforming metal material into webs to form metal parts, said installation comprising, on the one hand, an operable progressive tool comprising a plurality of workstations successively arranged between a first station a workstation and a last work station, and secondly a power supply to be able to provide a longitudinal band of a metallic material having a succession of band portions, said band being intended to be driven sequentially to through said progressive tool, from said first work station to said last work station, at a given pitch, while said progressive tool is operated at each step so that said plurality of work stations simultaneously causes the transformation of a plurality of portions of strip, and so as to gradually form between said first work station and said last work station metal parts. The installation comprises heating elements installed upstream of at least one of said work station of said plurality of work stations, said heating members being advantageously adapted to come into contact with said strip of metallic material to be able to provide thermal energy by conduction to said strip of metallic material. These heating elements make it possible to implement the progressive transformation method described above.

It will further be observed that the heating elements coincide with the work stations.

Preferably, said heating members supply said thermal energy to at least one portion of strip of metallic material, so as to be able to circumscribe the areas requiring this thermal energy for the transformation which will follow immediately.

It will be observed that the supply of thermal energy to the strip of metallic material is preferred in the vicinity of the first work station, where the strip portions have not yet been formed, so as to facilitate precisely this energy supply. . It is indeed easier to transmit this thermal energy when the band portions are still relatively flat.

If the tool includes workstations for cutting the strip portions, it is preferable to provide them at the beginning of the tool so that it can then bring thermal energy to the flat strip portions so as to then form them. .

Also, said strip of metal material having two opposite faces, said heating members comprise two elements for providing said thermal energy simultaneously to said two opposite faces. The two elements of the heating elements are for example heated by means of electrical resistance. In addition, said band of metal material is compressed between said two elements. The band portion and thus confined between these two elements so as to increase the thermal energy transfer.

Other features and advantages of the invention will emerge on reading the following description of a particular embodiment of the invention, given by way of indication but not limitation, with reference to the accompanying drawings in which:

- Figure 1 is a schematic view of a progressive processing installation for implementing the transformation method according to the invention and according to an alternative embodiment; and,

- Figure 2 is a schematic perspective view showing the result of the progressive transformation process obtained in the installation shown in Figure 1.

Figure 1 illustrates an installation 10 for progressive transformation of metal material into a strip. The installation 10 comprises a tool 12 having a plurality of work stations 14, 16, 18, 20, 22, 24, successively mounted in a press not shown. The input of the tool 12 is located at the first work station 14, while the output is at the last work station 14. The installation 10 also comprises, on the input side, a coil 26 of a strip 25 of an aluminum alloy, having a thickness of one millimeter here. The aluminum alloy used here is for example the AW-5083 H 1 1 1. On the output side, the installation 10 includes a waste container 27 of parts.

The first three work stations 14, 16, 18 are intended to cut the aluminum alloy strip, while the last three 20, 22, 24 are intended to form, then to separate, the metal parts obtained as will be explained below.

Between the first three and the last three work stations, heating elements 28 are installed inside the tool 12. Also, they are intended to be implemented with the tool 12 via the hurry. Therefore, when the tool 12 is implemented, all the work stations are also simultaneously with the heating members 28. The heating members 28 have a lower flat heating element 30 and an upper flat heating element 32, adjusted facing.

The work stations 14, 16, 18, 20, 22, 24 respectively have lower dies 34, 36, 38, 40, 42, 44 held in a fixed position flush with a plane P, and moving parts which overlie them. Also, the lower flat heating element 30 is flush with the plane P. In this way, the aluminum alloy strip 25 may extend longitudinally along the plane P flush with the lower dies 34, 36, 38, 40 , 42, 44 as well as the lower flat heating element 30.

The flat heating elements, lower and upper 32, are respectively formed of a plate equipped with electrical resistors. In this way, it is easy to wear them at a given temperature, for example 250 ° C.

Thus, the plurality of work stations 14, 16, 18, 20, 22, 24, and the heating members 28, are intended to be actuated simultaneously by means of the press via the tool 12.

The moving parts of the work stations 14, 16, 18, 20, 22, 24, will then come to cooperate simultaneously with the corresponding lower matrices 34, 36, 38, 40, 42, 44 and held in a fixed position, while the band 25 extends between. In the same way, and in parallel, the upper flat heating element 32 will come forcefully against the strip 25 which is itself bears against the lower flat heating element 30. A portion of metal material strip is thus taken in a vice between the two flat heating elements 30, 38. This preheating operation is also called "tabling". In this way, the two flat heating elements 30, 38 conductive, simultaneously from the two opposite faces of the band portion, thermal energy, uniformly and in an extremely short period of time. The two flat heating elements 30, 38 are for example brought to a temperature of 250 ° C, while the clamping time between the two flat heating elements 38, 30 is equal to two seconds, according to a particularly advantageous embodiment . Thus, in this example, the tool 12 is driven by a movement of 30 shots per minute. Thus, and more specifically, at each stroke, the work stations 14, 16, 18, 20, 22, 24 and the heating member 28 are implemented for a period of one second. The first three work stations 14, 16, 18 then make it possible to cut three first portions 48, 50, 52 of the band 25, while a fourth portion 54 is left free and a fifth portion 56 is heated to a value about 200 ° C. It reaches such a value during the second tightening of the lower flat heating elements 30 and upper 32.

Also, sixth 58 and seventh portions 60 are then deformed by penultimate 22 and antepenultimate 20 work stations, while a last portion 62 is detached from the seventh portion 60 through the last work station 24. The latter portion 62 can then come into the recovery tank 27.

After two seconds, the moving parts of the work stations 14, 16, 18, 20, 22, 24 as well as the upper flat heating element 32 are lifted in a fraction of a second, while the alloy strip 25 aluminum is advanced one step, equivalent to the distance separating two adjacent work stations.

In this way, it is understood that the sixth band portion 58, here U-shaped, has been brought to a temperature of 200 ° C at the instant before between the heating members 28. Also, given the rate imposed on the tool, the sixth band portion 58 already has a temperature close to 200 ° C when it is deformed through the third workstation 20.

FIG. 2 shows an extended band portion in the tool after it has been implemented. It contains the fifth flat portion 56 which has been brought to temperature. It contains the first three portions 48, 50, 52 which have been cut, and the last three portions 58, 60, 62 which have been deformed and detached for the last one. Thus, the cutting operations were carried out before the forming operations, so as to be able to supply thermal energy by tabling to the fifth portion.

The implementation example shown in Figures 1 and 2 is not limiting. Also, the concept according to the invention can be applied well other forms of more complex pieces. The number of heaters can of course be increased, and precede several work stations to deform parts of the band. The temperature values are obviously to be adjusted according to the thickness of the strip of material used. In this way, it is possible to significantly increase the rates of the installation to obtain quality parts at an advantageous cost. The advantage of hot forming may be, in addition to the productivity obtained with the progressive tool, to have reduced the springback. Therefore, the geometry of the pieces is precisely in accordance with that defined by the matrices.

The progressive transformation method according to the invention can be applied to aluminum alloys of the 5000 series, but it can also be applied to other metallic material, for example alloys of magnesium, copper and alloy. copper or stainless steels.

Claims

1. A method of progressively transforming metallic web material (25) to form metal parts, said method being of the type comprising the following steps:

an actuatable progressive tool (12) is provided comprising a plurality of work stations (14, 16, 18, 20, 22, 24) successively arranged between a first work station (14) and a last work station (24). ;

providing a longitudinal strip (25) of a metallic material having a succession of strip portions (48, 50, 52, 54, 56, 58, 60, 62); and,

sequentially driving said strip (25) through said progressive tool (12), from said first workstation (14) to said last work station (24), at a given pitch, while said progressive tool is actuated (12) at each step so that said plurality of work stations (14, 16, 18, 20, 22, 24) simultaneously causes the transformation of a plurality of band portions, and so as to progressively form between said first station working (14) and said last work station (24) metal parts;

characterized by providing thermal energy to said strip of metallic material (25) by conduction upstream of at least one of said plurality of work stations (14, 16, 18, 20) , 22, 24).

2. Progressive transformation process according to claim 1, characterized in that said thermal energy is supplied to at least one band portion (48, 50, 52, 54, 56, 58, 60, 62).

3. Process of progressive transformation according to claim 1 or 2, characterized in that said thermal energy is supplied at the operating frequency of the press.

4. Progressive transformation method according to any one of claims 1 to 3, characterized in that, said strip of metal material (25) having two opposite faces, said thermal energy is supplied simultaneously to said two opposite faces.

5. Progressive transformation process according to any one of claims 1 to 4, characterized in that said compressed strip of metal material (25) between two heating elements.

6. Apparatus for progressively transforming (10) metallic web material (25) to form metal parts, said installation comprising, on the one hand, an operable progressive tool (12) having a plurality of work stations (14, 16, 18, 20, 22, 24) successively arranged between a first work station (14) and a last work station (24), and on the other hand a feed (26) to be able to provide a longitudinal band of a metallic material (25) having a succession of strip portions (48, 50, 52, 54, 56, 58, 60, 62), said strip (25) being intended to be driven sequentially through said progressive tool (12), said first workstation (14) to said last workstation (24) at a given pitch, while said progressive tool (12) is operated at each step so that said plurality of workstations (14, 16, 18, 20, 22, 24) simultaneously causes the transformation a plurality of strip portions, and so as to progressively form between said first work station (14) and said last work station (24) metal parts;

characterized in that it comprises heating elements (28) installed upstream of at least one of said work station of said plurality of work stations (14, 16, 18, 20, 22, 24), said heating (28) being adapted to come into contact with said strip of metallic material (25) to be able to supply thermal energy by conduction to said strip of metallic material (25).

7. Progressive transformation plant according to claim 6, characterized in that said heating members (28) supply said thermal energy to at least one portion of the strip (48, 50, 52, 54, 56, 58, 60, 62). of metallic material.

8. Progressive transformation plant according to claim 6 or

7, characterized in that, said strip of metallic material (25) having two opposite faces, said heating members comprise two elements (30, 32) for supplying said thermal energy simultaneously to said two opposite faces.

9. Progressive transformation plant according to claim 8, characterized in that said strip of metallic material (25) is compressed between said two elements (30, 32).