METHOD FOR APPLYING 3D METALLIC GRAPHICS WITH COUNTER-DEFORMATIONS

Abstract

The invention relates to a method for applying metallic 3D printing to mechanical parts in order to provide them with reinforcement elements. This method includes the prior positioning of these parts relative to the printing means, characterized in that said parts are positioned taking into account, on the one hand, isostatic points and, on the other hand, secondary pressure points previously known through a preliminary numerical simulation phase and intended to counteract potential deformations resulting from printing by simultaneously exerting counter-deformations in order to print the parts in a nominal position. (Fig. 2)

Description

Title of the invention: Method for applying 3D metal printing with counter-deformations

[0001] The invention applies to the field of strengthening mechanical parts previously produced and shaped.

[0002] More specifically, the invention relates to a method intended to provide, locally, on motor vehicle parts, by a so-called additive manufacturing method, a quantity of material intended to provide a complementary reinforcement function while neutralizing any possible deformations.

[0003] Generally speaking, parts used in the automotive sector are structured and sized to meet predetermined and well-defined mechanical constraints. A need for additional functions or characteristics, and in particular stiffening, generally requires a new design, at least partial, of these parts which can affect the overall manufacturing cost of the vehicles.

[0004] Today there are different methods for implanting and / or assembling, a posteriori, functional interfaces on mechanical parts or on structural elements which have been previously produced and shaped (by stamping, folding, etc.).

[0005] However, traditional methods which consist of adding metal elements to an existing structure or part require, at the same time, having a large space to house this part, manufacturing additional elements which generates significant costs and then assembling these elements on the structure or part.

[0006] A known method uses the technique of locally associating with these parts metal reinforcement elements in the form of stiffening ribs produced by means of a method comprising the application of 3D printing of metal in parts of these parts remote from their assembly zones. Such a printing method is implemented by melting, for example, a metal powder or a metal wire using the so-called DED technique (for "Direct Energy Deposition" which uses a laser, or the so-called WAAM technique (for "Wire Arc Additive Manufacturing") which uses an electric arc.

[0007] However, the application of a metallic 3D print on a part generates, due to the rise in temperature, deformations and tensions which are often uncontrolled and which are likely to significantly degrade the conformity of the printed parts.

[0008] At the same time, the stiffening provided by 3D metal printing on the support parts must meet a geometry that meets expectations, in particular, with a view to the fitting of these parts and their subsequent integration into the vehicles.

[0009] Indeed, the stamped parts are relatively flexible and although any differences in geometry resulting from printing can be compensated for by a subsequent ironwork operation to conform these parts to their environment, if these parts do not respect the expected geometry, they will not be able to adapt to this operation. In addition, the parts on which 3D printing is to be carried out also have their own dispersions and manufacturing tolerances.

[0010] Patent FR3059648B1 describes a method of manufacturing a frame element aircraft using an additive manufacturing method consisting of producing reinforcing ribs on a base plate. However, this method does not provide for conforming this element before producing the ribs and does not address the problem of deformations resulting from 3D printing.

[0011] In this context, and because the geometric deformations linked to 3D metal printing can be simulated digitally and be known before implementing the method, the invention sought a solution which, in its most general aspect, makes it possible to resolve in a simple and effective manner the technical problems posed by the methods previously used.

[0012] Thus, the invention proposes a solution for reinforcing a mechanical part by means of a method of applying 3D printing which jointly makes it possible to counter the potential deformations generated during the implementation of the printing.

[0013] This aim is achieved, according to the invention, by means of a method for applying a 3D metallic print to mechanical parts in order to provide them with reinforcing elements, this method comprising the prior positioning of these parts relative to the printing means, characterized in that said parts are positioned taking into account, on the one hand, the iso-statism points and, on the other hand, secondary pressure points previously known by a prior phase of numerical simulation and intended to counter the potential deformations resulting from the subsequent printing by jointly exerting counter-deformations in order to print the parts in a nominal position.

[0014] According to a preferred embodiment of the method of the invention, the secondary pressure points coincide with the position of the printing means.

[0015] Preferably, the parts intended to be reinforced by the method of the invention are previously formed by stamping.

[0016] Thus, the invention provides that the secondary pressure points are also determined as a function of the conformity of the parts resulting from the prior stamping.

[0017] Another object of the invention is a mechanical part reinforced by means of a method as defined above.

[0018] Yet another object of the invention is a motor vehicle provided with at least one mechanical part reinforced by means of the method having the characteristics defined above.

[0019] Thus, in principle, the invention proposes an improvement to the traditional methods of implanting reinforcement elements which overcomes the technical difficulties encountered with the prior methods by making it possible to obtain, still by means of a process of applying 3D printing, reinforced parts having a geometry conforming to expectations, in particular, with a view to their subsequent fitting and integration on vehicles.

[0020] Furthermore, the method of the invention can be implemented with traditional tools on the existing production line and is compatible with all parts generally present on motor vehicles.

[0021] From a logistical point of view, the invention avoids the need to purchase parts from external suppliers by producing stamped parts which are reinforced directly on the assembly site as required.

[0022] Thanks to the 3D printing process, the material is only used in the right quantity needed, unlike standardized solutions which are not necessarily adapted to the need.

[0023] Other characteristics and advantages of the invention will emerge on reading the description which follows, with reference to the appended figures, for which:

[0024] [Fig.l] is a graph representing the dimensional differences between the series part (bottom curve 1) produced without 3D printing (or before 3D printing) and the reinforced part (top curve 2) by a traditional 3D printing method.

[0025] [Fig.2] is a graph representing the dimensional deviations between the series part (bottom curve 1) produced without 3D printing (or before 3D printing) and the reinforced part (top curve 2a) using an improved 3D printing process according to the invention with the production of counter-deformations.

[0026] For clarity, identical or similar elements are indicated by identical reference signs in the following description and in the figures.

[0027] Naturally, the modes of implementation of the invention, the results of which are illustrated schematically by [Fig. 2] presented above and described below, are given only as non-limiting examples. It is explicitly provided within the scope of the invention that different modes can be proposed and combined together to propose others.

[0028] The invention relates to the field of the installation of one or more functional interfaces on a mechanical support part and is more particularly interested in to reinforce these parts which are intended to be mounted on motor vehicles.

[0029] The method of the invention consists of an improvement of existing reinforcement methods (illustrated by [Fig.l]) the result of which on the treated parts is illustrated by [Fig.2].

[0030] The method of the invention comprises a 3D metal printing operation on mechanical parts, previously formed by stamping, in order to provide them with reinforcing elements. Such a method generally comprises the prior positioning of these parts relative to the printing means (DED “Direct Energy Deposition” type laser or WAAM “Wire Arc Additive Manufacturing” type electric arc).

[0031] The method of the invention provides for positioning the parts to be reinforced taking into account, on the one hand, the isostatic points and, on the other hand, secondary pressure points previously known by a prior phase of numerical simulation.

[0032] The iso-statism points are the points used to position the part in space during the application of the printing process and serve as reference points for the design and quality and conformity checks of this part. These points are checked by probing or by scanner in order to know their position relative to the nominal and thus validate the deformation in the controlled area.

[0033] After positioning these parts, the secondary pressure points make it possible to constrain the part and generate voluntary deformations during the application of the 3D printing process.

[0034] These secondary pressure points are thus intended to counter potential deformations likely to appear during 3D printing and to jointly exert counter-deformations in order to print the parts in a nominal position.

[0035] According to a specific characteristic of implementation of the method of the invention, these secondary pressure points coincide with the position of the printing means. The invention provides, alternatively, that the secondary pressure points are also determined as a function of the conformity of the parts resulting from their prior stamping.

[0036] Figures 1 and 2 are graphs showing the deformations measured on the parts with 3D printing, respectively, according to a traditional method and according to the method of the invention with counter-deformations. The profiles of these parts are compared to the series parts which have not been printed.

[0037] On the abscissa are the points of the profile to be checked and on the ordinate, the dimensional measurements compared to the nominal, the bars showing the difference measured between two profiles with and without 3D printing.

[0038] [Fig.l] schematically represents the dimensional differences E between a stamped and series part produced without 3D printing or before this 3D printing (lower curve 1) and a stamped and reinforced part with a traditional 3D printing method (upper curve 2).

[0039] [Fig. 2], for its part, schematically represents the dimensional differences E between a stamped and series part produced without 3D printing or before this 3D printing (lower curve 1) and a stamped and reinforced part using the 3D printing method according to the invention (upper curve 2a). A comparison between the lower curves 2 and 2a of the graphs of figures 1 and 2 shows that the profile obtained with stress points during 3D printing implemented according to the method of the invention is the one which is closest to the series part.

[0040] Consequently, the dimensional deviations resulting from 3D printing according to the method of the invention are significantly reduced. This result is obtained thanks to a specific positioning of the part relative to the printing means and the provision of counter-deformations during printing.

Claims

Claims

1. Method for applying a 3D metal print to mechanical parts in order to provide them with reinforcing elements, this method comprising the prior positioning of these parts relative to the printing means, said parts are positioned taking into account, on the one hand, the iso-statism points and, on the other hand, secondary pressure points previously known by a prior phase of numerical simulation and intended to counter the potential deformations resulting from the printing by jointly exerting counter-deformations in order to print the parts in a nominal position, characterized in that the secondary pressure points coincide with the position of the printing means.

2. Method according to the preceding claim, characterized in that the parts intended to be reinforced are previously formed by stamping.

3. Method according to the preceding claim, characterized in that the secondary pressure points are also determined as a function of the conformity of the parts resulting from the prior stamping.

4. Mechanical part reinforced by means of a method according to one of the preceding claims.

5. Motor vehicle provided with at least one reinforced mechanical part according to the preceding claim.

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