METHOD FOR PRODUCING A PART BY ADDING MATERIAL

Abstract

The invention relates to a method for producing a part made of plastic material for a motor vehicle, said part comprising at least one first section to which at least one second section is applied, in which the first section is produced. The second section of the part made of plastic material is produced by three-dimensional printing directly onto the first section of the part.

Claims

1. A method for producing a part made of plastic material for a motor vehicle and including at least one first section and at least one second section, the method comprising: applying the at least one second section to the at least one first section, wherein the at least one first section is produced, producing the at least one second section by three-dimensional printing directly on the at least one first section, wherein the at least one first section includes at least one mechanical attachment area for mechanically attaching the at least one second section to the at least one first section.

2. The method according to claim 1, wherein the at least one mechanical attachment area comprises a three-dimensional network of ribs.

3. The method according to claim 1, wherein the at least one first section comprises at least two attachment areas, each attachment area defining a surface, a normal direction to the surface of each attachment area not being parallel to each other.

4. The method according to claim 1, wherein the at least one second section comprises a functional element and/or a reinforcement element.

5. The method according to claim 1, wherein the method further comprises, to produce the at least one first section: producing at least one metal block having a three-dimensional network of ribs which are complementary to ribs of a three-dimensional network of the at least one first section, placing the at least one metal block in a mold at a location of the first section where the three-dimensional network is to be created, and molding the first section of the part.

6. The method according to claim 1, wherein a material of the at least one first section of the part comprises one of polypropylene, polyamide, acrylonitrile butadiene styrene, polystyrene-b-poly(ethylene-butylene)-b-polystyrene, and a combination thereof.

7. The method according to claim 1, wherein a material of the at least one second section of the part comprises one of polypropylene, polyamide, acrylonitrile butadiene styrene, polystyrene-b-poly(ethylene-butylene)-b-polystyrene, and a combination thereof.

8. The method according to claim 1, wherein, before producing the second section by three-dimensional printing, the method comprises: applying a surface treatment to the first section of the part.

9. The method according to claim 1, wherein the plastic material forms a bodywork part.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] We will now describe several embodiments of the invention given as non-limiting examples in reference to the drawings, on which:

[0028] FIG. 1 is a cross-sectional view of a first part made of plastic material obtained by the method of the invention;

[0029] FIG. 2 is a larger-scale view of a detail of FIG. 1 showing a cross-sectional view of a three-dimensional network of ribs;

[0030] FIGS. 3 to 5 are top views of three examples of three-dimensional networks of ribs;

[0031] FIG. 6 is a diagrammatic view of a mold for producing the first section of the part according to the method of the invention;

[0032] FIG. 7 is a cross-sectional view of a second part made of plastic material obtained by the method of the invention;

[0033] FIG. 8 is a partial perspective view of a third part made of plastic material obtained by the method of the invention.

MORE DETAILED DESCRIPTION

[0034] FIG. 1 shows a cross-sectional view of a part 10 made of plastic material for a motor vehicle obtained by the method of the invention.

[0035] This part 10 comprises a first section 12 to which at least one second section 14 is applied. These two sections are made of plastic material.

[0036] The first section comprises an area 16 for mechanically attaching the second section 14 to the first section 12.

[0037] The second section 14 of the part 10 can act as mechanical reinforcement for the first section 12 of the part. It can also be used to attach other elements to the part 10 and/or to attach the part 10 to the motor vehicle.

[0038] As can be seen on FIG. 2 which is a larger-scale view of the mechanical attachment area 16 of FIG. 1 and on FIGS. 3 to 5, the mechanical attachment area 16 comprises a three-dimensional network 18 of ribs 20.

[0039] FIGS. 3 to 6 show different embodiments of the three-dimensional network 18. In these top views, we see that the three-dimensional network 18 may take various forms.

[0040] The ribs 20 may be arranged together so as to form a continuous network of ribs 20 having, for example, a plurality of ribs 20 parallel to each other and connected to each other by other ribs 20, as shown on FIGS. 3 and 4.

[0041] The three-dimensional network 18 may also be formed by ribs 20 which form crosses in pairs, the crosses being distributed over the attachment area 16, as shown on FIG. 5.

[0042] We will now describe the method for producing the part 10.

[0043] The part 10 made of plastic material is obtained by producing the first section 12 by molding and then by printing the second section 14 directly on the first section 12 using the three-dimensional printing technique.

[0044] Advantageously, mechanical attachment areas 16 can be provided on the first section 12.

[0045] These mechanical attachment areas 16 may be materialized on the first section 12 by three-dimensional networks 18 of ribs 20. These three-dimensional networks 18 are obtained by the presence, in a mold 22 for producing the first part 12, of areas having a three-dimensional network 24 of ribs 26 which are complementary to the ribs 20 of the three-dimensional network 18 of the first section 12.

[0046] Preferably, these areas having a three-dimensional network 24 of ribs 26 are formed on a metal block 28 applied in a section 30 of the mold 22 for producing the first section 12.

[0047] Thus, depending on the number of metal blocks 28 present in the mold 22 and the presence or absence of an area 24 having a three-dimensional network of ribs 26 on these metal blocks 28, it is possible to produce in the same mold 22 first sections 12 of a part 10 having mechanical attachment areas 16 arranged at different locations on the first section 12 and/or having different three-dimensional networks 18 of ribs 20.

[0048] Thus, by replacing the metal block 28 by another metal block not provided with an area 24 having a three-dimensional network of ribs 26, a first section 12 is obtained which, in the area of this metal block, does not have a three-dimensional network 18 of ribs 20.

[0049] Furthermore, three-dimensional printing of the second section 14 on the first section 12 can be carried out after a step of surface treatment of the first section, for example by applying one or more coats to make a paint adhere to the first section 12 and by applying a coat of paint or chromium-plating.

[0050] FIG. 7 shows a diagrammatic cross-sectional view of a bodywork part for motor vehicle, for example a bumper skin 32. Note that this bumper skin 32 is not flat. Typically, this bumper skin 32 has a thickness of a few millimeters, while it may have a length of over one meter. Also, the bumper skin 32 comprises a first “appearance” section 12, which is visible from outside the vehicle and a second section 14 used to reinforce the first section 12 to prevent in particular the bumper skin 32 from deforming and denting if pressure is exerted on it. The second section 14 may also comprise functional elements used to attach the bumper skin to the vehicle or to attach other elements to the bumper skin, such as park distance control (PDC) sensors which assess the distance to an obstacle located in the sensor's field of view like a camera or a radar.

[0051] In this cross-sectional view, the first section 12 comprises three mechanical attachment areas 16′, 16″ and 16′″ each having a three-dimensional network 18 of ribs 20. Each attachment area 16′, 16″, 16″ defines a surface and a normal 34′, 34″, 34′″ to this surface. The normals 34′, 34″, 34′″ are not parallel to each other in pairs.

[0052] Since at least two of the normals 34′, 34″, 34′″ are not parallel to each other, the second section 14 cannot be removed from the first section 12.

[0053] FIG. 8 shows a partial perspective view of a bodywork part 36 for a motor vehicle. This part 36 comprises a skin made of plastic material forming the first section 12 of the part 36 and a second section 14 having a continuous three-dimensional network 38 of ribs 40 forming a honeycomb which mechanically strengthens the skin, and therefore the first section 12. As can be seen on FIG. 8, ribs 40 are fitted with clips 42 in order, for example, to attach cables to the part 36 or to attach the part 36 to the motor vehicle.

[0054] The second section 14 of the part 36 also comprises another functional element 44 arranged between ribs 40 and attached to these ribs. This element 44 locally strengthens the first section 12 of the part 36 and acts as a means of attaching another element (not shown) to the part 36.

[0055] Obviously, numerous modifications can be made without leaving the scope of the invention.