METHOD FOR CONTROLLING DEFORMATIONS CAUSED BY ADDITIVE METALLIC MANUFACTURING ON A STAMPED PART

Abstract

METHOD FOR CONTROLLING DEFORMATIONS CAUSED BY ADDITIVE METAL MANUFACTURING ON A STAMPED PART The present invention relates to a method for controlling deformations induced by the temperature rise of a stamped part (2) during the addition of reinforcing material by additive manufacturing on one face (2.1) of said part, notable in that said method comprises a pre-deformation of the stamped part prior to the addition of reinforcing material, said pre-deformation having a geometric deviation (e) between said pre-deformed stamped part (2') and a nominal reference shape of said stamped part, said pre-deformation being configured to allow a return of said pre-deformed stamped part to the nominal reference shape, so as to compensate for future deformations of said stamped part generated by the subsequent temperature rise during the addition of reinforcing material. (Figure to be published with the abbreviation: Figure 1)

Description

Title of the invention: METHOD FOR CONTROLLING DEFORMATIONS CAUSED BY ADDITIVE METALLIC MANUFACTURING ON A STAMPED PART technical field

[0001] The present invention relates to the field of motor vehicles, more particularly to the field of reinforced parts by additive manufacturing for motor vehicles. Previous technique

[0002] Conventionally, several methods exist for reinforcing a part that has been previously formed and shaped by stamping, bending, etc. A common practice is to weld or, using 3D printing, apply a reinforcing element to a specific area of ​​the part. This additive manufacturing reinforcement process aims to optimize the amount of material added to the base part in an overall quest to reduce the weight of mechanical parts, particularly for automotive structures.

[0003] Such a process is implemented by melting, for example, a metal powder or a metal wire using the so-called DED "Directed Energy Deposition" technique, which uses a laser, or WAAM "Wire Arc Additive Manufacturing", which uses an electric arc.

[0004] However, adding material by 3D printing leads to a significant increase in temperature on the base part. This temperature rise, unavoidable and inherent to the choice of process, can cause deformation of the part after its reinforcement, which is detrimental to the assembly operations of said part with other surrounding components, resulting in assembly non-conformities.

[0005] The patent document published FR 3 124 099 Al proposes to create on one face an excess thickness of material intended to compensate for future deformations caused by the temperature rise of a part during a 3D printing on an opposite face of said part.

[0006] However, the solution proposed by the document has room for improvement, in particular to provide more precision in maintaining the initial shape of the part before its deformation due to the rise in temperature. Description of the invention

[0007] The present invention aims to overcome at least one of the drawbacks of the aforementioned prior art. More specifically, the invention aims to to offer a simple, efficient and economical solution to avoid deformation of stamped sheet metal parts when adding reinforcing metal by additive manufacturing.

[0008] To this end, the invention relates to a method for controlling deformations induced by the temperature rise of a stamped part during the addition of reinforcing material by additive manufacturing on one face of said part, remarkable in that said method includes a pre-deformation of the stamped part prior to the addition of reinforcing material, obtaining a pre-deformed stamped part exhibiting a geometric deviation from a nominal reference shape of said stamped part, said pre-deformation being configured to allow a return of said pre-deformed stamped part to the nominal reference shape in order to compensate for future deformations of said stamped part generated by the subsequent temperature rise during the addition of reinforcing material.

[0009] According to one embodiment, the pre-deformation includes an increase in a bend angle between two halves of the stamped part and / or includes the formation of a bend angle targeting one or more portions of said stamped part.

[0010] According to one embodiment, the increase in the bending angle between the two halves of the stamped part, or the bending angle formed at the right of a corresponding portion of said stamped part, is equal to at most 30°.

[0011] Advantageously, the geometric deviation between the pre-deformed stamped part and the nominal reference shape of said stamped part is defined by the increase and / or formation of the bend angle(s).

[0012] According to one embodiment, the pre-deformation is carried out directly during the stamping of the part.

[0013] According to one embodiment, additive manufacturing includes a WAAM technique for electric arc deposition of a metal wire, or a DED technique for powder bed fusion or metal wire deposition using a laser.

[0014] The invention also relates to a reinforced part remarkable in that it is obtained by means of a process according to the invention.

[0015] According to one embodiment, said part comprises a thin thickness of between 1 mm and 4 mm. Preferably, the part is made from sheet metal.

[0016] The invention also relates to a motor vehicle comprising at least one part according to the invention.

[0017] The measures of the invention are advantageous in that the targeted pre-deformation of the stamped part makes it possible to compensate effectively and precisely for future deformations caused by the subsequent rise in temperature during the addition of reinforcing material.

[0018] Furthermore, since the pre-forming can be carried out directly during the stamping phase of the part, this ensures a fast manufacturing process and considerably facilitates the assembly of the motor vehicle. Brief description of the drawings

[0019] [Fig-1] represents a perspective view of a pre-deformed stamped part relative to a nominal reference shape of said stamped part;

[0020] [Fig.2] represents a perspective view of the stamped part of [Fig.1] after having undergone deformations generated by the subsequent rise in temperature during an addition of reinforcing material, said stamped part having subsequently recovered its nominal reference shape. Detailed description

[0021] Fig. 1 represents a perspective view of a pre-formed stamped part 2' (visible in dotted lines) with respect to a nominal reference shape 2 of said stamped part.

[0022] The stamped part 2 includes a face 2.1 intended to receive a metallic reinforcement (visible in [Fig.2]) 3D printed preferably by a DED technique of powder bed fusion or metal wire deposition using a laser, and more preferably by a WAAM technique of electric arc deposition of a metal wire.

[0023] The printing of the reinforcement on face 2.1 is preferably carried out at room temperature, while the melting temperature of the printing metal filament generates a significant temperature gradient between the different faces of part 2. This increases the stresses on said part 2, causing undesirable deformations. The inventors have observed that the more pronounced the gradients, the greater the risk of deformation of the parts after the reinforcement has been 3D printed.

[0024] Advantageously, the present invention proposes to pre-deform the stamped part 2 in a precise and targeted manner, and preferably during its stamping phase, in order to compensate for the future deformations of said stamped part generated by the subsequent rise in temperature during the addition of reinforcing material.

[0025] In this regard, the pre-deformation is preferably achieved by increasing a bend angle α between two halves 2.2, 2.3 of the stamped part 2, or by forming a bend angle [3 targeting one or more portions 2.4 of said stamped part 2, or by a combination of the latter two.

[0026] In this configuration, the pre-deformation exhibits a geometric deviation e between the pre-deformed stamped part 2' and the nominal reference shape 2, this deviation geometric e is defined by the increase and / or by the formation of the bending angle(s) a, [3.

[0027] The nominal reference shape 2 of the stamped part can correspond to a reference digital model of said stamped part.

[0028] In the example illustrated in [Fig.1], the increase in the bending angle a is along a vertical axis Y, while the formation of the bending angle [3 targeting the distal portion 2.4 is along a transverse axis Z. Preferably, each of these bending angles a, [3 is at least equal to 5°, and does not exceed 30°.

[0029] Preferably, the pre-deformation is based mainly on an empirical analysis of past deformation data, which advantageously makes it possible to significantly improve the accuracy of the anticipation of future deformations due to metallic 3D printing on face 2.1.

[0030] Fig. 2 represents a perspective view of the stamped part of Fig. 1 after undergoing deformations generated by the subsequent rise in temperature during the addition of reinforcing material 4, said stamped part 2 having subsequently recovered its nominal reference shape.

[0031] Advantageously, the stamped part 2 corresponds to a part reinforced by means of the printed reinforcement 4, said part is preferably made of thin sheet metal having a thickness between 1 and 4 mm, and more preferably between 1 and 3 mm.

[0032] Advantageously, the pre-deformed part 2' of [Fig.1] has here recovered its nominal reference shape 2 following the subsequent rise in temperature during the addition of reinforcing material 4, which allowed the reverse return of the pre-deformed part to its designated initial configuration.

[0033] Following the metal 3D printing phase, the stamped part 2 can thus be subsequently integrated with other parts in the same tooling as one which has not received reinforcement by 3D printing (which has not undergone deformations), with a view to their assembly on the same motor vehicle.

[0034] Advantageously, the process of the invention makes it possible to avoid having tooling requiring counter supports for holding in position during the metal 3D printing phase.

[0035] The present invention considerably facilitates the assembly of the structure of motor vehicles, in particular by allowing a diversity of parts with or without reinforcement (depending on the variant of the vehicle) without being forced to have several tools in the rest of the assembly process, because the two parts (with or without reinforcement) will have absolutely the same geometry, without any deformation, and this, thanks to the present invention.

Claims

Demands

1. A method for controlling deformations induced by the temperature rise of a stamped part (2) during the addition of reinforcing material (4) by additive manufacturing on one face of said part (2), characterized in that said method comprises a pre-deformation of the stamped part prior to the addition of reinforcing material (4), obtaining a pre-deformed stamped part (2') exhibiting a geometric deviation (e) from a nominal reference shape (2) of said stamped part, said pre-deformation being configured to allow a return of said pre-deformed stamped part (2') to the nominal reference shape (2) so as to compensate for future deformations of said stamped part (2) generated by the subsequent temperature rise during the addition of reinforcing material (4).

2. A method according to claim 1, wherein the pre-deformation includes an increase in a bend angle (a) between two halves (2.2, 2.3) of the stamped part (2) and / or includes the formation of a bend angle (|3) targeting one or more portions (2.4) of said stamped part (2).

3. A method according to claim 2, wherein the increase in the bending angle (a) between the two halves (2.2, 2.3) of the stamped part (2), or the bending angle (|3) formed at the right of a corresponding portion (2.4) of said stamped part (2), is equal to at most 30°.

4. A method according to any one of claims 1 to 3, wherein the pre-deformation is directly carried out during the stamping of the part (2).

5. A method according to any one of claims 1 to 4, wherein the additive manufacturing comprises a WAAM technique for electric arc deposition of a metal wire, or a DED technique for powder bed or metal wire deposition using a laser.

6. Reinforced part (2) for motor vehicle, characterized in that it is obtained by means of a process according to any one of claims 1 to 5.

7. Part (2) according to claim 6, wherein said part (2) comprises a thin thickness of between 1 mm and 4 mm.

8. Motor vehicle comprising at least one part (2) according to one of claims 6 and 7.

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