Manufacturing process of a vehicle part

Abstract

This method of manufacturing a vehicle part (2) comprises a step of applying a layer of paint (6) on one face of a transparent or translucent part (4) a step of partially irradiating the layer of paint (6) with laser radiation (10) so as to etch the layer of paint (6) according to a predefined pattern and in a part of its thickness. Figure for the abstract: figure 2

Description

Title of the invention: Method for manufacturing a vehicle part

[0001] The invention relates to a motor vehicle part. More particularly, the invention relates to a method for manufacturing a transparent vehicle part contributing to the exterior appearance of the vehicle.

[0002] A vehicle comprises several transparent parts intended to transmit light. These include parts used for regulatory lighting purposes, for example those protecting the headlight units of the main and dipped beam headlights or the indicator lights. Furthermore, the vehicle may also have light sources intended for decorative purposes which improve the aesthetics of the vehicle.

[0003] For these purposes, it is possible to treat a surface of the transparent parts in order to improve their appearance. One possibility for doing this is to overmould a film onto the surface of the transparent part, the film having a predefined opaque pattern. In this way, when the light source associated with the transparent part emits light, the latter is partially blocked by the opacity of the pattern and transmitted by the parts of the part which are not covered by the pattern. This makes it possible to improve the aesthetics of the light beam transmitted, by the transparent part, from the light source to the external environment. Another possibility is to decorate the transparent part by painting and marouflage, which makes it possible to obtain a similar result.

[0004] These options are interesting but can pose problems. Indeed, a film as described above or a marouflage can pose problems of color matching with the paint of the vehicle, which has a negative impact on the aesthetics of the vehicle. In addition, the application of the film or the marouflage may not allow to obtain a pattern of as high precision as desired. In addition, these techniques can pose problems of aging.

[0005] To overcome these problems, it is known, for example from document FR 1912347 A1, to apply a layer of paint to a transparent part and then to etch it by laser irradiation according to a predefined pattern. The layer of paint is then removed over its entire thickness in the area of ​​the pattern, which allows the passage of light through the transparent part in the area of ​​the pattern. However, this solution is not entirely satisfactory since a problem remains in the passage of light through the parts of the transparent part which are not covered by the pattern. Indeed, the light is transmitted freely through these parts, so that the elements behind the part are visible from the outside if the light source associated with the transparent part is switched off. This mainly concerns the light source and possibly wiring elements. The exposure of these elements is not not desired as it detracts from the overall aesthetics of the vehicle, so it is best to avoid it.

[0006] The invention aims in particular to remedy these problems by proposing a method which does not pose a problem of color matching with the vehicle paint, which is more precise than that of the prior art and which makes it possible to conceal the elements located behind the transparent part.

[0007] To this end, the invention relates to a method for manufacturing a vehicle part comprising the following steps:

[0008] - application of a layer of paint on one side of a transparent part or translucent, and

[0009] - partial irradiation of the paint layer with laser radiation in a manner to engrave the layer of paint according to a predefined pattern and in part of its thickness.

[0010] It is thus possible to apply the paint to one side of the transparent part and then partially remove it in its thickness by engraving using laser radiation according to a chosen predefined pattern. In other words, only a residue of paint layer remains in the area of ​​the predefined pattern. It is understood that the laser makes it possible to remove the paint in order to obtain a more precise rendering than by implementing one of the methods of the prior art discussed above. In addition, the fact that the color of the coating is given by paint and not by a film or marouflage as in the prior art makes it possible to choose a paint which corresponds to that used for the bodywork of the vehicle. It follows that fewer color matching problems arise.Furthermore, the manufacturing process only involves a single step of coating the transparent or translucent part, namely the paint layer, so that the process only requires a single pass through a workshop or paint deposition line (understood here in the broad sense). This helps to make the manufacturing process simple and quick to implement and, more generally, to make the manufacturing process more industrially competitive.

[0011] The paint layer residue present in the pattern area makes it possible to prevent seeing through the transparent or translucent part when a light source is associated with the transparent or translucent part and switched off, without however preventing the transmission of the light emitted by the light source when it is switched on. It is thus understood that the elements located behind the transparent or translucent part are prevented from having an impact on the aesthetics of the vehicle since they are hidden by the paint layer.

[0012] Advantageously, the layer of paint is a layer of lacquer.

[0013] By "lacquer" is meant a paint with a hardener. As examples of embodiment, the lacquer can be made from thermosetting resins, in particular alkyd or glycerophthalic, or polyurethane-based. Such a lacquer allows a colored finish to be obtained with a layer thickness much less than the thickness required to achieve such a finish with conventional paint.

[0014] Advantageously, the paint layer comprises a transparent primer undercoat. Advantageously, the lacquer layer comprises a transparent primer undercoat.

[0015] Advantageously, the laser radiation has the following parameters: wavelength in the infrared, working power between 5 and 10 W, scanning speed between 1800 and 2200 mm / s, pulse frequency between 25000 and 35000 Hz.

[0016] This makes it possible to etch the paint layer in part of its thickness in a particularly controlled and reproducible manner.

[0017] Advantageously, the paint layer has a thickness of between 1 and 8 μm in the predefined pattern after partial irradiation.

[0018] Such a thickness corresponds to a good compromise between the transmission of light through the paint layer residue in the pattern area and the concealment of the light source when it is switched off.

[0019] Advantageously, the transparent or translucent part is manufactured by molding a plastic, for example polycarbonate (PC), polypropylene (PP), polyamide (PA), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyurethane (PU), polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), styrene acrylonitrile (SAN), acrilonitrile styrene acrylate (ASA), polymethyl methacrylate (PMMA), cycloolefin copolymer (COC) or cycloolefin polymer (COP).

[0020] The transparent or translucent part is thus simple to produce and inexpensive.

[0021] Advantageously, the layer of paint is opaque, and preferably colored black or gray.

[0022] The opacity of the paint or lacquer makes it possible to improve the quality of the illumination of the pattern produced by a light source placed behind the vehicle part, by preventing the formation of a blurred light halo on the edges of the pattern.

[0023] Advantageously, a light source is installed opposite the layer of paint.

[0024] The layer of paint is thus intended to be oriented towards the interior of the vehicle. when the vehicle part is installed in a vehicle. In this way, there is no need to protect the paint layer from external damage, for example mechanical stress or ultraviolet radiation from the sun.

[0025] The invention also provides a vehicle part comprising a transparent or translucent part on which is deposited a layer of paint having a first thickness in a predefined pattern and a second thickness outside the predefined pattern, the first thickness being less than the second thickness.

[0026] Advantageously, the vehicle part has, in the predefined pattern, a coefficient of haze, or “coefficient of haze”, greater than or equal to 60%, preferably greater than or equal to 75%, for example approximately equal to 80%, preferably greater than or equal to 90%.

[0027] Advantageously, the vehicle part has, in the predefined pattern, a transparency greater than or equal to 20%, preferably greater than or equal to 30%, preferably between 35% and 45%.

[0028] These values ​​correspond to a good compromise between the transmission of light through the paint layer in the pattern area and the concealment of the light source when it is switched off.

[0029] Advantageously, the vehicle part further comprises a light source installed opposite the paint layer. Brief description of the figures

[0030] The invention will be better understood on reading the following description given solely by way of example and with reference to the appended drawings in which:

[0031] [Fig-1] is a sectional view of a first step in the implementation of a method of manufacturing a vehicle part according to an embodiment of the invention,

[0032] [Fig.2] is a sectional view of a second step in the implementation of a method for manufacturing a vehicle part according to an embodiment of the invention, and

[0033] [Fig.3] is a sectional view of a third step in the implementation of a method for manufacturing a vehicle part according to an embodiment of the invention. Detailed description

[0034] [Fig.l] shows a first step of a method of manufacturing a vehicle part 2 according to an embodiment of the invention.

[0035] The vehicle part 2 comprises a transparent or translucent part 4 intended to protect a light source. By "transparent", respectively "translucent", is meant that it is at least transparent, respectively translucent, to any light radiation having a wavelength included in the visible spectrum, that is to say between approximately 380 and 780 nm. The part 4 is here transparent and made of a plastic having this characteristic, in this case polycarbonate commonly referred to as "PC". However, it is possible to make the part of a completely different plastic, for example polypropylene (PP), polyamide (PA), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyurethane (PU), polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), styrene acrylonitrile (SAN), acrylonitrile styrene acrylate (ASA), polymethyl methacrylate (PMMA), cycloolefin copolymer (COC) or cycloolefin polymer (COP). The transparent or translucent part 4 is made by molding. Such a process being known, it will not be detailed further in the following.

[0036] The vehicle part 2 comprises a layer of paint 6 which is deposited on a first face of the transparent or translucent part 4, this first face being intended to be oriented towards the interior of the vehicle when the vehicle part 2 is installed in a vehicle. The layer of paint is here a layer of lacquer 6, but the invention can be implemented with a so-called “conventional” layer of paint. By “lacquer” is meant a paint with a hardener. As examples of embodiment, the lacquer can be made based on thermosetting resins, in particular alkyd or glycerophthalic, or based on polyurethanes. Here, the layer of lacquer 6 is opaque. Preferably, it is black or gray in color. The layer of lacquer 6 has a thickness approximately equal to 25 μm.Optionally, a transparent primer undercoat is deposited under the lacquer layer 6, where appropriate, the transparent primer undercoat has a thickness of between 25 and 30 μm. In the following, the term “lacquer layer” will be used to refer to the lacquer layer 6 itself and the transparent primer undercoat if it is present.

[0037] The vehicle part 2 comprises a layer of varnish 8 which is deposited on a second face of the transparent or translucent part 4 opposite the first face. In other words, the layer of varnish 8 and the layer of paint 6 are deposited on opposite faces of the transparent or translucent part 4. The layer of varnish 8 makes it possible to protect the transparent or translucent part 4 from any ultraviolet radiation to which it may be exposed, in particular from the sun. This is particularly advantageous if the transparent or translucent part 4 is made of polycarbonate.

[0038] According to the first step of the method for manufacturing the vehicle part 2, the varnish layer 8 and the lacquer layer 6 are deposited on the transparent or translucent part 4. The lacquer layer 6 has a sufficient thickness so that it completely absorbs any light beam in the visible spectrum. This thickness is here between 25 and 50 μm.

[0039] [Fig. 2] shows a second step of the manufacturing process of the vehicle part 2. In this step, a part of the vehicle part 2 is irradiated using laser radiation 10 so as to etch the lacquer layer 6. This operation is commonly referred to by the English term “laser-etching” which can be translated as “laser engraving”. The laser radiation 10 has the following parameters: wavelength in the infrared, working power between 5 and 10 W, scanning speed between 1800 and 2200 mm / s, frequency of pulse between 25000 and 35000 Hz. As an exemplary embodiment, the laser radiation 10 here has the following parameters: wavelength equal to 1064 nm, working power equal to 8 W, scanning speed equal to 2000 mm / s, pulse frequency equal to 30000 Hz. Irradiation by means of the laser radiation 10 burns the lacquer layer 6 in the area of ​​the pattern so that only burnt residues of this layer remain, the laser radiation being configured to achieve this result. In the area of ​​the pattern, the residues migrate partly into the transparent or translucent part 4 and form a thin residual layer of lacquer. This is not very dense, heterogeneous and has an appearance of sparse grains so that it transmits light in a diffuse manner.

[0040] The irradiation is carried out only in a part of the vehicle part 2 in the sense that it is carried out according to a predefined pattern formed on the lacquer layer 6. It is controlled so that the lacquer layer 6 is irradiated in the pattern but only in a part of its thickness, but not the transparent or translucent part 4. If it is present, the transparent primer undercoat makes it possible to protect the transparent or translucent part 4 from the heat effect of the laser radiation 10 by creating a separation distance between the irradiated lacquer layer 6 and the transparent or translucent part 4. It has in fact been found that the transparent or translucent part 4 has a tendency to yellow, in particular if it is made with polycarbonate, under the effect of the laser radiation 10 without the presence of the primer undercoat.

[0041] After irradiation, the lacquer layer 6 has two levels.

[0042] In the area of ​​the predefined pattern, the layer of lacquer 6 is present over a first thickness equal to a fraction of its original thickness, here between 1 and 8 μm. In this area, the vehicle part 2 has a coefficient of haze, or more commonly referred to as a “coefficient of haze” in English, greater than or equal to 60%, preferably greater than or equal to 75% and preferably greater than 90%, and has a transparency greater than or equal to 20%, preferably greater than or equal to 30% and preferably between 35% and 45% (ideally equal to 40%).

[0043] Outside the area of ​​the predefined pattern, the lacquer layer 6 is intact and has a second thickness equal to the thickness of the lacquer layer 6 as deposited. The first thickness is therefore less than the second thickness.

[0044] After the irradiation step, an additional step of polishing the transparent or translucent part 4 can be provided. This makes it possible to improve the transparency in the area of ​​the predefined pattern and, more generally, the aesthetics of the vehicle part 2. In addition, this polishing makes it possible to round off the corners formed by the engraving carried out during the irradiation step, and therefore to attenuate the phenomena of light diffusion which could disturb a light beam passing through the vehicle part 2. vehicle 2.

[0045] [Fig. 3] shows a third step of the method for manufacturing the vehicle part 2. In this step occurring after the irradiation step, a light source 12 is associated with the transparent or translucent part 4. Here, the light source 12 is installed opposite the lacquer layer 6, so that the latter is oriented towards the interior of the vehicle when the vehicle part 2 is installed in a vehicle. In other words, the lacquer layer 6 is deposited on the face of the transparent or translucent part 4 (first face) opposite the face of the transparent or translucent part 4 visible from the outside (second face) when the vehicle part 2 is installed in the vehicle. This configuration is generally referred to as the lacquer layer 6 being located on face B, or "B-side" in English terms. The varnish layer 8 is deposited on face A, or "A-side".Thus, the first and second faces previously introduced correspond respectively to face B and face A.

[0046] When the light source 12 is switched off, so that it does not emit light, it is not visible through the transparent or translucent part 4 due to the presence of the lacquer layer 6, over its entire thickness outside the area of ​​the pattern and over the partial thickness in the area of ​​the pattern.

[0047] When the light source 12 is switched on, so that it emits light towards the transparent or translucent part 4, the light is transmitted through the partial lacquer layer 6 in the pattern area and blocked by the lacquer layer 6 outside the pattern area. Because the lacquer layer 6 is opaque, and moreover black or gray in color, it does not alter or only slightly alters the color of the transmitted light, and the light transmission takes place without the formation of a blurred light halo on the edges of the pattern area.

[0048] The invention is not limited to the embodiments presented and other embodiments will become clear to those skilled in the art.

[0049] The light source may be part of a vehicle's low beam and high beam optical unit, a vehicle's indicator light optical unit, or a decorative light optical unit.

[0050] The paint or lacquer may be made of a colored material. In this way, the diffusion of light, emitted by the light source, through the partial layer of lacquer is accompanied by a coloring of the light, which gives it a certain aesthetic effect.

[0051] An alternative embodiment may be provided in which the paint layer or the lacquer layer is deposited on face A of the transparent or translucent part. In this case, the varnish layer is deposited above the paint layer or the lacquer layer, and face B of the transparent or translucent part, in front of which where the light source is placed, can be left bare. List of references

[0052] 2: vehicle part 4: transparent or translucent part 6: layer of paint / layer of lacquer 8: layer of varnish 10: laser radiation 12: light source

Claims

Claims

1. Method for manufacturing a vehicle part (2), characterized in that it comprises the following steps: - application of a layer of paint (6) on one face of a transparent or translucent part (4), and - partial irradiation of the layer of paint (6) with laser radiation (10) so as to etch the layer of paint (6) according to a predefined pattern and in a part of its thickness.

2. Method according to the preceding claim, in which the paint layer (6) is a lacquer layer.

3. Method according to any one of the preceding claims, in which the laser radiation (10) has the following parameters: wavelength included in the infrared, working power between 5 and 10 W, scanning speed between 1800 and 2200 mm / s, pulse frequency between 25000 and 35000 Hz.

4. A method according to any preceding claim, wherein the paint layer (6) has a thickness of between 1 and 8 pm in the predefined pattern after the partial irradiation.

5. A method according to any one of the preceding claims, wherein the transparent or translucent part (4) is manufactured by molding a plastic, for example polycarbonate, polypropylene, polyamide, polyethylene terephthalate, polybutylene terephthalate, polyurethane, polyvinyl chloride, styrene butadiene acrylonitrile, styrene acrylonitrile, styrene acrylate acrylonitrile, polymethyl methacrylate, cycloolefin copolymer or cycloolefin polymer.

6. A method according to any preceding claim, wherein the paint layer (6) is opaque, and preferably black or gray in color.

7. A method according to any preceding claim, wherein a light source (12) is installed opposite the paint layer (6).

8. Vehicle part (2), characterized in that it comprises a transparent or translucent part (4) on which is deposited a layer of paint (6) having a first thickness in a predefined pattern and a second thickness outside the predefined pattern, the first thickness being less than the second thickness.

9. Vehicle part (2) according to claim 8, having, in the predefined pattern, a coefficient of haze, or "coefficient of haze", greater than or equal to 60%, preferably greater than or equal to 75%, more preferably greater than or equal to 90%.

10. Vehicle part (2) according to claim 8 or 9, having, in the predefined pattern, a transparency greater than or equal to 20%, preferably greater than or equal to 30%, preferably between 35% and 45%.

11. A vehicle part (2) according to any one of claims 8 to 10, further comprising a light source (12) installed opposite the paint layer (6).

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