Method for producing transparent or translucent vehicle part

Abstract

The invention relates to a method for producing a motor vehicle body part (2), characterized in that it comprises the following steps: depositing at least one opaque coating on at least a portion of a face (6) of a body (3) of said body part (2), said body (3) being made of a transparent or translucent plastic material; and-removing the opaque coating by means of a laser beam locally irradiating the opaque coating in order to achieve a set of microperforations (8, 10) of the opaque coating, the irradiation path (12, 16, 22) of the laser beam being formed exclusively by a continuous substantially linear trajectory (12 ', 16', 22 ').

Description

Technical Field

[0001] The present invention relates to a motor vehicle part. More specifically, the present invention relates to a method for manufacturing a transparent or translucent vehicle part that contributes to the vehicle's appearance, and an apparatus for implementing the method. Background Art

[0002] Vehicles include a plurality of transparent or translucent parts designed to transmit light. This particularly relates to parts for legal lighting purposes, such as parts that protect the optical units of main headlights, dipped headlights, or turn signals. Additionally, a vehicle may also have light sources provided for decorative purposes to improve the vehicle's aesthetics.

[0003] For these purposes, the outer or inner surface of a part made of transparent or translucent plastic can be treated to improve its appearance. A feasible solution for achieving this lies in overmolding an opaque cover or film on the outer surface of the part, and the opaque film has a predetermined pattern that allows light to pass through. Thus, when the light source associated with the part emits light, the light is partially blocked due to the light-impermeability of the opaque film and is partially transmitted through the part facing the pattern. This allows for improving the aesthetics of the light beam transmitted from the light source to the external environment through the transparent or translucent part. The opaque film as described above may cause color correspondence problems with the paint of other vehicle parts, which has a negative impact on the vehicle's aesthetics.

[0004] It is also known to paint the outer or inner surface of a transparent or translucent body panel and then remove a greater or lesser part of the applied paint layer, for example, by implementing micro-perforations or areas of larger dimensions on the paint layer by means of a laser to remove all the paint in these areas, thereby making these areas transparent or translucent. The aim pursued is to allow light from behind the body part to pass through.

[0005] In the case of micro-perforations, the size and distribution of these micro-perforations on the body panel are set such that while allowing visible light emitted from the inner surface of the body panel to propagate to the outside of the body panel, it does not allow the light source to be seen through the body panel from the outside of the vehicle when one or more light sources are extinguished, and at the same time, it maintains an overall appearance close to that of the painted body part without removing the paint on the body part due to the small size of the micro-perforations.

[0006] Micro-perforations achieved by means of a laser generally have a substantially circular shape, and the number of micro-perforations on the treated surface can be relatively large (numerous). In fact, the area that can let light through can be several centimeters or dozens of centimeters, and the micro-perforations can have dimensions of 20 to 1000 microns, preferably 50 to 700 microns, more preferably 100 to 300 microns, and can be spaced from each other by 1 to 4 times the size of the micro-perforations, preferably spaced 2 to 3 times the size of the micro-perforations, and more preferably spaced at a distance approximately equal to 2 times the size of the micro-perforations. Implementing a large number of circular micro-perforations has several drawbacks:

[0007] - The cycle time for achieving micro-perforations is quite long, due to the circular shape of the micro-perforations. This shape is usually obtained by implementing concentric circles with a laser, or by circularly scanning the contour of a circle with a laser and then scanning along a straight-line trajectory within the defined contour. These two options result in a long cycle time for micro-perforations. Given the large number of micro-perforations intended to be achieved on the panel to obtain the desired visual effect (taking into account the size of the micro-perforations and their spacing on the surface as described above), which can be at least 4 micro-perforations per square millimeter (i.e., 40,000 micro-perforations on a square surface with a side length of 100 mm), the cycle time for achieving the final body panel can be quite long (considering that the desired cycle time is shorter than 5 minutes, preferably 1 to 2 minutes, the problem of an overly long cycle time occurs when implementing at least 5000 to 10,000 micro-perforations).

[0008] - The programming of the robot carrying the laser is quite complex, resulting in a cumbersome and thus difficult-to-process programming file by a machine. Summary of the Invention

[0009] The object of the present invention is in particular to solve these problems by proposing a method that allows shortening the cycle time for achieving micro-perforations and thus reducing the cycle time for manufacturing the final decorated panel.

[0010] To this end, the subject of the present invention is a method for manufacturing a motor vehicle body part, which comprises the following steps:

[0011] - Depositing at least one opaque coating on at least a part of the face of the body of the body part, the body being made of a transparent or translucent plastic material; and

[0012] - Removing the opaque coating by locally irradiating the opaque coating with a laser beam to achieve a set of micro-perforations in the opaque coating, the laser beam irradiation trajectory consisting only of continuous substantially straight trajectory lines.

[0013] "Transparent" and "translucent" respectively mean that the part is transparent and translucent respectively for at least any wavelength including light radiation in the visible light, i.e., light with a wavelength of approximately 380 to 780 nm, or any infrared radiation (i.e., radiation with a wavelength of approximately 780 nm to 1 mm).

[0014] The term "micro-perforation" means removing the paint layer from a surface where the maximum dimension from the irradiated surface is between 20 and 1000 μm, preferably between 50 and 700 μm, more preferably between 100 and 300 μm.

[0015] The term "local irradiation" means removing material over the entire thickness of the coating. The coating can be paint, such as a three-layer paint (a colored paint with a thickness of 5 to 20 μm, a primer with a thickness of 10 to 40 μm, and a varnish with a thickness of 25 to 40 μm, i.e., a total thickness of 40 to 100 μm), a metallized coating with a thickness of 1 to 5 μm, printing ink, a coating deposited by pad printing or screen printing, a film attached to a body part (and including ink, paint, etc.), etc. Laser irradiation can remove the coating over the entire thickness of the coating (or in the case of a deposited film, remove the coating present on the film, and the film is used to support the coating), for example, in the thickness range of 1 to 100 μm for the above thickness examples.

[0016] Thus, micro-perforation is achieved only by an irradiation trajectory that only includes a trajectory line consisting of substantially straight lines, which simplifies the trajectory and saves time compared to the much more complex trajectories in the prior art that mix straight and curved lines. Moreover, compared to the prior art, programming the trajectory that only includes linear displacement (movement) is less complex and easier to handle by a machine.

[0017] According to the manufacturing method, other optional technical features that can be adopted alone or in combination:

[0018] - The irradiation trajectory at least partially includes a repeated identical trajectory line pattern, which is composed of multiple continuous substantially straight trajectory lines;

[0019] - At least one trajectory line consists of an irradiated section and a non-irradiated section of an opaque coating to achieve at least a part of multiple micro-perforations;

[0020] - The focal length between the emission source of the laser beam and the surface of the body part is 100 to

[0021] 1000 mm, preferably 300 to 700 mm, more preferably 400 to 600 mm;

[0022] - Within the irradiation trajectory on the surface of the body part, change the focal length between the emission source of the laser beam and the surface of the body part;

[0023] - at least a portion of the microperforations is substantially in the shape of a parallelogram, preferably substantially in the shape of a square or rectangle;

[0024] - the width of the scanning band of the laser beam on the said surface of the body part is 40 to 200 μm,

[0025] Preferably 70 to 120 μm, more preferably approximately equal to 100 μm;

[0026] - the opaque coating is formed by at least one lacquer layer, a printing ink, a metallized coating, a coating deposited by pad printing or screen printing;

[0027] The subject of the invention is also a production plant for producing motor vehicle body parts, comprising:

[0028] - at least one for depositing on at least a portion of the surface of the body part

[0029] at least one deposited component having an opaque coating, the main body being made of a transparent or translucent plastic material; and

[0030] - at least one emission source for emitting a laser beam, the emission source being arranged to remove the opaque coating by locally irradiating the opaque coating with the laser beam to achieve a set of microperforations of the opaque coating, the laser beam emission source being arranged to generate an irradiation trajectory of the laser beam consisting only of continuous substantially rectilinear trajectory lines.

[0031] Advantageously, the laser beam emission source is arranged to change the focal distance between the laser beam emission source and the surface of the body part during irradiation of the surface of the body part. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The invention will be better understood from the following description which is given by way of example only and which is made with reference to the accompanying drawings, in which:

[0033] [ Figure 1 ] is a view of a vehicle body panel including micro-perforations achieved by the method according to the present invention;

[0034] [ Figure 2 ] is a partial view of an area including micro-perforations achieved by the method according to the present invention;

[0035] [ Figure 3 ] is a diagram of micro-perforation achieved by the method according to the first embodiment of the present invention;

[0036] [ Figure 4 ] is a diagrammatic representation of micro-perforation achieved by a method according to a second embodiment of the present invention; and

[0037] [ Figure 5is similar to Figure 4 a diagram of a group of micro-perforations similar to the micro-perforations. Detailed implementation

[0038] In Figure 1 a body part 2 is shown, which includes a transparent or translucent body 3 and a region 4 of micro-perforations achieved by the method according to the present invention, and Figure 2 a partial view of the micro-perforation region 4 including a group of micro-perforations (here the second micro-perforation 10 as described below) is shown.

[0039] In Figure 1 the example shown, the body part 2 is a front bumper. Of course, it can also relate to any other body part, such as a tailgate, a grille, a rear bumper, etc. It can also relate to parts attached to a body panel.

[0040] Figure 1 the body part 2 of includes two micro-perforation regions. Of course, the number of micro-perforation regions 4 can be different, just as one or more dimensions of the micro-perforation regions 4 can be different. The micro-perforation regions 4 can have the same size or different sizes, including more or fewer micro-perforations, etc.

[0041] The micro-perforation region 4 can be implemented on the outer face 6 of the body part 2 and / or on the inner face (which is not visible in Figure 1 ). The outer face 6 refers to the face of the body part 2 that is visible from the outside of the vehicle when the body part 2 is installed on the vehicle. The inner face refers to the face of the body part 2 that is opposite to the outer face 6 and is not visible from the outside of the vehicle when the body part 2 is installed on the vehicle.

[0042] The micro-perforations of the micro-perforation region 4 are respectively at the micro-perforation region 4 ( Figure 2 shows three rows including five micro-perforations), having the same / different shapes, and having transparency (or translucency) that allows light radiation emitted from the rear of the body part 2 (i.e., the inner face facing the body panel 2) by a visible light source or an infrared radiation source to pass through, while not allowing these light sources or radiation sources to be seen through the body panel 2, especially when the visible light source is not activated. It should be reminded that "transparent" and "translucent" respectively mean that the part is transparent and translucent at least for any light radiation with wavelengths in the visible spectrum, i.e., approximately 380 to 780 nm, or for any infrared radiation with wavelengths of approximately 780 nm to 1 mm. The visible light source is preferably an optical device including light-emitting diodes (LEDs). The infrared radiation source can be LIDAR.

[0043] The body part 2 is made of a material that is transparent or translucent to light, and this material is non-exclusively, for example:

[0044] - Polycarbonate (PC);

[0045] - Polymethyl methacrylate (PMMA);

[0046] - Acrylonitrile-butadiene-styrene (ABS), or styrene-acrylonitrile (SAN), acrylonitrile-styrene-acrylate (ASA), and mixtures thereof;

[0047] - Amorphous polyolefin, such as cycloolefin copolymer (COC) or cycloolefin polymer (COP);

[0048] - Polyethylene terephthalate (PET);

[0049] - Polypropylene (PP);

[0050] - Polyamide (PA);

[0051] - Polybutylene terephthalate (PBT);

[0052] - Polyurethane (PU); and

[0053] - Polyvinyl chloride (PVC).

[0054] The implementation method of the body part 2 (such as injection or thermoforming) or the dimensions and shape of the body part 2 are known to those skilled in the art and will not be described in detail herein.

[0055] The manufacturing method according to the present invention includes the following steps:

[0056] - Depositing (applying) at least one opaque coating on at least one part of one surface of the main body 3 of the body part 2. As described above, this can be, for example, paint (which consists of a single layer or multiple layers), ink, etc. Generally, this refers to a coating that does not allow visible light or infrared radiation emitted by a light source arranged behind the body part 2 to pass through, and one or more layers of this coating can be locally removed by using a laser beam.

[0057] This deposition can be carried out on the outer surface 6 or the inner surface of the body part 2.

[0058] This deposition can be carried out on the outer surface 6 or the inner surface of the body part 2.

[0059] - By means of a laser beam with a locally irradiated opaque cladding, the opaque cladding is removed to form a set of micro-perforations on the opaque cladding. The irradiation path (trajectory) of the laser beam consists only of substantially straight successive trajectory lines. Within the scope of the present invention, a part of the opaque cladding is irradiated by the laser beam to completely remove the opaque cladding in terms of thickness (as defined above) at one or more micro-perforation regions 4, so as to obtain the transparent or opaque micro-perforations as described above. The removal of the opaque cladding enables the exposure of the body 3, which may be transparent or opaque itself. Therefore, at the micro-perforations, visible light or infrared radiation can thus pass through the vehicle body part 2, which is the vehicle body panel 2 here.

[0060] The size of the micro-perforations and their arrangement relative to each other (for example, the distance between two adjacent micro-perforations) are selected to achieve the above-mentioned desired effect, that is, to allow the radiation emitted by the light source to pass through, but not to make the light source visible from the outside through the vehicle body part 2, especially when the visible light source is turned off. The source of the laser beam is configured (by parameters) to be able to obtain: micro-perforations with the desired shape(s) and size(s), the desired spacing between micro-perforations, or the desired transparency at the micro-perforations. The configured parameters are especially as follows:

[0061] - The focal length between the source of the laser beam and the vehicle body part 2;

[0062] - The power of the laser beam;

[0063] - The scanning speed of the micro-perforation region 4;

[0064] - The exposure time of the area irradiated (exposed) by the laser beam;

[0065] - Whether the trajectory (path) lines overlap (cover), and the percentage of overlap between the trajectory lines;

[0066] - Whether the trajectory lines corresponding to irradiation or non-irradiation alternate, or whether there are irradiated and non-irradiated parts within the same trajectory line;

[0067] - When the laser is a pulsed laser, the frequency of the laser;

[0068] - The wavelength of the laser source.

[0069] Figure 3 and Figure 4 Shows two micro-perforations 8 and 10 with different shapes. Figure 3 Shows a first micro-perforation 8 according to the first embodiment of the present invention, which has an arbitrary shape here. It only includes a first trajectory line 12' consisting of basic straight lines (at Figure 3The first trajectory 12 (marked out in two in

[0070] Figure 4 shows the second micro-perforation 10 according to the second embodiment of the present invention. The second trajectory line 16' which only includes substantially straight lines (marked out in two in Figure 4 allows the second micro-perforation 10 to be obtained. The second trajectory 16 is composed of a plurality of trajectory lines having substantially the same segments and aligned to obtain a second irradiation region 18 having a rectangular shape. According to the second embodiment of the present invention, the irradiation trajectory (here the second irradiation trajectory 16) at least partially includes a repeated identical trajectory line pattern 20, and the trajectory line pattern 20 is composed of a plurality of continuous straight trajectory lines (here the second trajectory line 16') (marked out two successive patterns 20 in Figure 4 ). The repetition of the same pattern allows further simplification of the programming of the movement of the source of the laser beam.

[0071] Figure 5 shows a set of second micro-perforations 10 which form two sets of aligned second micro-perforations 10. These eight micro-perforations 10 together form at least a part of the micro-perforation region 4. In this example, the third trajectory line 22 allows the entire row of the second micro-perforations 10 to be realized. Of course, the number of trajectories for realizing the whole set of micro-perforations can be changed. For example, all the micro-perforations shown in Figure 5 can be realized by a single trajectory.

[0072] Like the first trajectory 12 and the second trajectory 16, the third trajectory 22 is composed of straight third trajectory lines 22'. However, at least a part of the third trajectory lines 22' ( Figure 5 the horizontal trajectory lines in Figure 5 ) includes an irradiation segment 24' and a non-irradiation segment 24". In this embodiment, the alternation of the irradiation segment 24' and the non-irradiation segment 24" enables at least one third trajectory line 22' ( Figure 5 the horizontal trajectory lines in

[0073] Preferably, the focal length between the emission source of the laser beam and the surface of the vehicle body part is from 100 to 1000 millimeters, preferably from 300 to 700 millimeters, and more preferably from 400 to 600 millimeters. Increasing the focal length enables a larger-sized impact point of the laser beam on the vehicle body part 2 and thus limits the number and / or amplitude of the movements of the laser beam to be implemented to achieve one or more micro-perforations. A large focal length also allows a larger area of the vehicle body part 2 to be scanned by a simple movement of one or more lenses of the laser beam source without having to move the laser beam source too frequently from one area to be scanned to another (only moving when the laser beam source reaches the spatial limit of the area of the vehicle body part 2 that it can process by a simple movement of the lens). Thus, there is a tendency towards an angular displacement of the laser beam, while the component carrying the laser beam source, such as a robotic arm, is fixed. Thereby, by increasing the surface (area) that can be irradiated by a simple movement of the lens of the laser beam source, the movement of the said carrying component is limited. It is even possible to reduce the number of laser beam sources used to process a given surface within the allocated time limit that must be adhered to.

[0074] Micro-perforation shapes that are easily achievable using the trajectories according to the present invention can be made to further shorten the manufacturing time of the vehicle body part 2. At least a part of the micro-perforations has a shape such that at least one side of the shape is parallel to the trajectory line. Figures 2 to 5 The micro-perforations are as follows. Preferably, at least a part of the micro-perforations is substantially in the shape of a parallelogram, preferably in the shape of a square or a substantially rectangular shape. As Figure 3 and Figure 4 shown by the simple irradiation paths in, this concerns shapes that are particularly easy to achieve by the method according to the present invention. As described above, for the reasons mentioned above (increasing the size of the irradiation surface by a simple angular movement of the lens), it makes sense for the laser beam to have a sufficiently large impact point on the surface of the vehicle body part. More generally, it is advantageous to determine the size of the impact point such that the scanning of the area to be irradiated can be optimized and to ensure that this size enables micro-perforations of the desired shape while also satisfying the irradiation speed, irradiation time, or the overlap between two irradiation trajectory lines. To this end, the width of the scanning band of the laser beam on the surface of the vehicle body part is from 40 to 200 μm, preferably from 70 to 120 μm, and more preferably approximately 100 μm.

[0075] The subject matter of the present invention also relates to a device for manufacturing vehicle parts, comprising:

[0076] - at least one deposition component for depositing at least one opaque coating on at least a part of the surface of the body 3 of the vehicle body part 2, the body 3 being made of a transparent or semi-transparent plastic material. This can relate to a robot for applying paint or a device for depositing (applying) an opaque film.

[0077] - At least one emission source for emitting a laser beam, which is arranged to remove an opaque coating by locally irradiating the opaque coating with the laser beam to achieve a set of micro-perforations in the opaque coating, and the laser beam emission source is arranged to generate an irradiation trajectory of the laser beam consisting only of continuous substantially straight trace lines.

[0078] Advantageously, for the above reasons, the emission source of the laser beam is arranged to be able to change the focal length between the emission source of the laser beam and the surface of the vehicle body part 2 during the irradiation of the surface of the vehicle body part 2.

[0079] List of reference numerals

[0080] 2: Vehicle body part

[0081] 3: Main body

[0082] 4: Micro-perforation area

[0083] 6: Outer surface

[0084] 8: First micro-perforation

[0085] 10: Second micro-perforation

[0086] 12: First trajectory

[0087] 12’: First trace line

[0088] 14: First irradiation surface

[0089] 16: Second trajectory

[0090] 16’: Second trace line

[0091] 18: Second irradiation surface

[0092] 20: Trace line pattern

[0093] 22: Third trajectory

[0094] 22’: Third trace line

[0095] 24’: Irradiation segment

[0096] 24”: Non-irradiation segment

Claims

1. A method for manufacturing a motor vehicle body part (2), characterized in that: The method comprises the following steps: - depositing at least one opaque coating on at least a portion of the face (6) of the body (3) of the body part (2), the body (3) being made of a transparent or translucent plastic material; and - removing the opaque coating by locally irradiating the opaque coating with a laser beam, the irradiation trajectory (12, 16, 22) of the laser beam consisting only of continuous substantially rectilinear trajectory lines (12', 16', 22').

2. The manufacturing method according to claim 1, wherein: The illumination trajectory (12, 16, 22) at least partially comprises a repeating identical trajectory line pattern (20) consisting of a plurality of consecutive substantially rectilinear trajectory lines (16').

3. The manufacturing method according to any one of the preceding claims, wherein: At least one track (22') is formed by an illuminated section (24') and a non-illuminated section (24") of the opaque coating to realize at least a portion of the plurality of microperforations (10).

4. The manufacturing method according to any one of the preceding claims, wherein: The focal distance between the emission source of the laser beam and the surface (6) of the body part (2) is 100 to 1000 mm, preferably 300 to 700 mm, more preferably 400 to 600 mm.

5. The manufacturing method according to any one of the preceding claims, wherein: The focal distance between the emission source of the laser beam and the surface (6) of the body part (2) is changed within an irradiation trajectory (12, 16, 22) of the surface (6) of the body part (2).

6. The manufacturing method according to any one of the preceding claims, wherein: At least a portion of the micro-perforations (8, 10) is substantially in the shape of a parallelogram, preferably substantially in the shape of a square or a rectangle.

7. A method of manufacturing as claimed in any one of the preceding claims, wherein: The width of the scanning zone of the laser beam on the surface of the body part is 40 to 200 μm, preferably 70 to 120 μm, more preferably approximately equal to 100 μm.

8. The manufacturing method according to any one of the preceding claims, wherein: The opaque coating is formed from at least one lacquer layer, a printing ink, a metallized coating, a coating deposited by pad printing or screen printing.

9. A manufacturing apparatus for manufacturing a motor vehicle body part, comprising: - at least one deposition means for depositing at least one opaque coating on at least a portion of a face (6) of a body (3) of the body part (2), the body (3) being made of a transparent or translucent plastic material; and - at least one emission source for emitting a laser beam, the emission source being arranged to remove the opaque coating by locally irradiating the opaque coating with a laser beam to achieve a set of microperforations of the opaque coating, the emission source of the laser beam being arranged to generate an irradiation trajectory (12, 16, 22) of the laser beam consisting only of continuous substantially rectilinear trajectory lines (12', 16', 22').

10. The manufacturing apparatus according to claim 9, wherein: The emission source of the laser beam is arranged to change the focal distance between the emission source of the laser beam and the surface (6) of the body part (2) during irradiation of the surface (6) of the body part (2).

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