Enamel engraving and texturing method

Abstract

The invention discloses an enamel engraving and texturing method. The invention relates to a method for engraving and texturing an article (1) comprising an ornament (2) at least partially filled with an enamel (3), said method comprising a step of laser ablation on the surface of the enamel (3) and / or within the enamel (3) using a femtosecond or picosecond laser to produce a structure (7).

Description

(19) State Intellectual Property Office (12) Invention Patent Application (10) Application Publication Number (43) Application Publication Date (21) Application Number 202510484018.1 (22) Application Date 2025.04.17 (30) Priority Data 24171993.9 2024.04.23 EP (71) Applicant Comadour Company Address Löcco, Switzerland (72) Inventors J. Romand B. Comport P. Würer G. Richter (74) Patent Agency China Patent Agency (Hong Kong) Limited 72001 Patent Attorney Moody Hou Yunzhong (51) Int.Cl. B44B 1 / 00 ​​(2006.01) B44B 3 / 00 (2006.01) B44B 1 / 06 (2006.01) B44B 3 / 06 (2006.01) (54) Invention Title: Enamel Engraving and Texturing Method (57) Abstract: Enamel Engraving and Texturing Method. The present invention relates to a method for engraving and texturing an article (1) comprising an ornament (2) at least partially filled with enamel (3), the method comprising the step of laser ablation on the surface and / or within the enamel (3) using a femtosecond or picosecond laser to produce a structure (7). Claims 2 pages Description 4 pages Drawings 15 pages CN 120828607 A 2025.10.24 CN 1 20 82 86 07 A 1. A method for engraving and texturing an article (1) comprising an ornament (2) at least partially filled with enamel (3), the method comprising the step of laser ablation on the surface and / or within the enamel (3) using a femtosecond or picosecond laser to produce a structure (7). 2. The engraving and texturing method according to any of the preceding claims, wherein it involves a penetrating ornament (2) at least partially filled with enamel (3) to form a so-called openwork enamel. 3. The engraving and texturing method according to any of the preceding claims, comprising the step of filling the structure (7) with material (4). 4. The engraving and texturing method according to any of the preceding claims, wherein the wavelength of the laser is in the near-infrared range, i.e., between 700 and 2500 nm; in the green range, i.e., between 510 and 560 nm; or in the ultraviolet range, i.e., between 200 and 400 nm. 5. The engraving and texturing method according to any of the preceding claims, wherein the structure (7) within the enamel (3) is obtained by focusing a laser beam (8) within the enamel (3) and by generating an impact matrix, while the structure (7) at the surface requires focusing the laser beam (8) near the surface.6. The engraving and texturing method according to the preceding claim, wherein the laser beam (8) passes completely through the enamel (3) to create a structure (7) on a surface opposite the incident point of the laser beam (8). 7. The engraving and texturing method according to any one of claims 4 to 6, wherein for the structure (7) within the enamel (3), the wavelength of the laser is in the near-infrared range; and for the structure (7) at the surface, the wavelength of the laser is in the green range. 8. A method for manufacturing an article (1) comprising a through-hole ornament (2) at least partially filled with enamel (3) to form a so-called openwork enamel, the manufacturing method comprising an engraving and texturing step according to any one of claims 2 to 7, and comprising, before or during the engraving and texturing step, the following steps: - obtaining a semi-finished product (5) defining an upper surface (5a) and a lower surface (5b) opposite to the upper surface (5a); - removing a portion of the semi-finished product (5) from the upper surface (5a) to produce an ornament (2a) that does not penetrate to the lower surface (5b); or alternatively, in the preceding step, directly obtaining the semi-finished product (5) having the non-through-hole ornament (2a); - depositing one or more layers of enamel (3) within the non-through-hole ornament (2a), and firing the enamel (3) after each layer has been deposited; - Preferably, the lower surface (5b) is machined by grinding to expose the enamel (3), and thus an article (1) is produced having a through-decoration (2) filled with enamel (3). 9. The manufacturing method according to the preceding claim, wherein the lower surface (5b) is intended to face the observer during use, the manufacturing method comprising the steps of depositing a layer of luminescent material on the enamel (3) after the step of firing the enamel (3) and depositing a protective layer (6) on the luminescent material layer before the machining step. 10. The manufacturing method according to any one of claims 8 to 9, wherein the semi-finished product (5) is made of a material with a melting point greater than or equal to 650°C. 11. The manufacturing method according to any one of claims 8 to 10, wherein the deposition of one or more layers of enamel (3) is performed by liquid spraying, using a brush, or by spraying powder. 12. The manufacturing method according to any one of claims 8 to 11, wherein the number of deposited enamel (3) layers is between 2 and 15, preferably between 3 and 10. Claims 1 / 2 Page 2 CN 120828607 A 13. The manufacturing method according to any one of claims 8 to 12, wherein during the step of depositing one or more layers of enamel (3), enamel (3) layers of different colors are deposited and / or the colors within the same layer are modulated.14. An article (1) having an ornament (2) made of enamel (3), the ornament (2) comprising a structure (7) on its surface and / or within the enamel (3). 15. The article (1) according to the preceding claim, characterized in that the structure (7) is filled with a material (4), the material (4) being another enamel or a material different from the enamel (3). 16. The article (1) according to the preceding claim, comprising a through ornament (2) made of openwork enamel having an enamel thickness greater than or equal to 0.5 mm, preferably greater than or equal to 0.8 mm. 17. The article (1) according to the preceding claim, comprising a layer of luminescent material covering the enamel (3) in the ornament (2). 18. The article (1) according to the preceding claim, wherein the article (1) is an external timepiece component or a component of a movement. 19. The article (1) according to any one of claims 14 to 18, wherein the article (1) is made of ceramic, preferably zirconium oxide, sapphire, or cermet. Claims 2 / 2 Page 3 CN 120828607 A Enamel Engraving and Texturing Method Technical Field

[0001] The present invention relates to a method for engraving and texturing articles with enamel decorations, such as plique-à-jour enamel decorations. The invention also relates to a method for manufacturing the article and the article produced by such method. Background Art

[0002] Many ancient techniques can be used to form decorations on translucent stone or glass slurry. In antiquity, many intaglio carvings were made with semi-precious stones or glass slurry. Thus, decorations were obtained by hand cutting and polishing, and in some cases by molding the glass slurry. Most of the articles found are decorated on the top; and in very few cases, on the bottom, thus producing a holographic effect.

[0003] In-material engraving has been used in the watch industry for many years. It can be used, for example, to make anti-counterfeiting marks, or to integrate decorative filigree into sapphire crystal. It can also be used to customize decorative items made of crystal or polycarbonate.

[0004] To date, enamel engraving has not been widely used because it requires skilled engraving techniques to avoid damaging the surface of the enamel and altering its color. Summary of the Invention

[0005] The object of the present invention is to develop an enamel engraving and texturing method that overcomes the above-mentioned disadvantages.

[0006] This method can be used for any enamel decoration, and particularly for openwork enamel decoration, i.e., for enamel through-hole decoration, the effect of which is that light passes through a miniature stained glass window of transparent or translucent enamel. More specifically, it can be applied to openwork enamel decoration with a thickness greater than or equal to 0.5 mm, thereby reducing the brittleness of the enamel, which is beneficial for those subjected to heavy pressure.Enamel decorations (e.g., external timepiece components, such as watch frames) are very important.

[0007] More specifically, the present invention relates to a method for engraving and texturing articles comprising decorations at least partially filled with enamel, the method comprising the step of laser ablation on the surface and / or within the enamel using a femtosecond or picosecond laser to create a structure.

[0008] The engraving and texturing method according to the invention allows for laser ablation while controlling surface finish and limiting color variations in the enamel.

[0009] Upstream of this engraving and texturing method, a manufacturing method that allows for the deposition of thick enamel layers in a short time can be used to produce articles with openwork enamel decorations, resulting in low-cost mass production with increased enamel durability.

[0010] To this end, a method for manufacturing an article comprising a through-hole decoration, which is at least partially filled with enamel to form a so-called openwork enamel, the manufacturing method comprising engraving and texturing steps, and comprising the following steps before or during the engraving and texturing steps:

[0011] - obtaining a semi-finished product defining an upper surface and a lower surface opposite the upper surface;

[0012] - removing a portion of the semi-finished product from the upper surface to produce a decoration that does not penetrate to the lower surface; or alternatively, in the preceding steps, directly obtaining the semi-finished product having a non-through-hole decoration;

[0013] - depositing one or more layers of enamel within the non-through-hole decoration, and firing the enamel after each layer has been deposited; Specification 1 / 4 page 4 CN 120828607 A

[0014] - preferably machining the lower surface by grinding to expose the enamel, and thus producing an article having a through-hole decoration filled with enamel.

[0015] This method is highly repeatable, thus allowing for mass production at very low cost. Complex shapes are limited only by the resistance of the substrate material during firing or impact.

[0016] This method allows for the deposition of thick enamel layers, resulting in enamels with a total thickness greater than or equal to 0.5 mm and a limited number of layers (typically less than 10 layers). This greater thickness of the enamel compared to prior art enamels means that it is less brittle and can therefore be used to make external components subjected to significant stress, such as watch frames.

[0017] Transparent enamel decorations with engravings will produce a depth that is currently unattainable. Brief Description of the Drawings

[0018] Figures 1A to 1F represent six steps of a first alternative embodiment of the method according to the invention for manufacturing an article, i.e., a watch frame, with enamel decorations. In each figure, an illustrated cross-sectional view of a portion of the article or semi-finished product and a three-dimensional view of a portion of the article or semi-finished product are shown. The three-dimensional views in Figures 1A and 1F are top views of the semi-finished product or article, respectively, while views 1B to 1E are bottom views of the semi-finished product.

[0019] Figure 2 is a three-dimensional view of a watch frame produced by the manufacturing method according to the first alternative embodiment.

[0020] Figures 3A to 3E represent five steps of a second alternative embodiment of the method according to the invention for manufacturing an article having enamel decoration, i.e., a pendulum. In each figure, a schematic cross-sectional view of a portion of the article or semi-finished product and a three-dimensional view of a portion of the article or semi-finished product are shown.

[0021] Figures 4A to 4C show schematic cross-sectional views of an article obtained, for example, by means of a first alternative embodiment of the manufacturing method according to the invention, representing a method for engraving and texturing an article having enamel decoration.

[0022] Figures 5A to 5C are schematic views of the steps of engraving and texturing enamel decoration by laser ablation. In Figure 5A, engraving is performed on the surface of the enamel; while in Figure 5B, engraving is performed within the enamel. In Figure 5C, engraving is performed on the surface opposite to the point of incidence of the laser beam. Detailed Description

[0023] The present invention relates to a method for engraving and texturing enamel decoration on an article. The article may be, for example, a timepiece component. More specifically, it can be an external component selected from a non-exhaustive list including the following parts: center, case back, bezel, crown, pushers, bracelet links, bracelet, clasp, buckle, dial, and hands. This method is particularly suitable for manufacturing articles subjected to high stress, such as external components. It can also include components of the movement, such as the balance wheel. The invention will be described in more detail hereafter with respect to the bezel and the balance wheel.

[0024] This engraving and texturing method can be used for any enamel decoration. The decoration can be a through decoration or it may not be a through decoration. The decoration can be completely filled with enamel, or filled with enamel and other materials (such as, for example, luminescent materials). In the case of a through decoration that is at least partially filled with enamel, it is referred to as an openwork enamel decoration.

[0025] The engraving and texturing method according to the invention is performed by laser ablation within or on the surface of the enamel. It should be noted that the term "engraving" will be used somewhat imprecisely to refer to the formation of recesses typically a few tenths of a millimeter in depth, and the term "texturing" will be used to refer to shallower engravings with depths a few hundredths of a millimeter. For simplicity, the term "engraving" will generally be used below to refer to either engraving or texturing.

[0026] These engravings are performed using very short pulses of laser light. The order of magnitude can range from picoseconds to femtoseconds. Typically, the values ​​in the specification (page 2 / 4, CN 120828607 A) range from 250 to 500 femtoseconds.

[0027] Near-infrared wavelengths (i.e., wavelengths between 700 and 2500 nm) and green wavelengths (i.e., wavelengths between 510 and 560 nm) can be used. Ultraviolet lasers with wavelengths between 200 and 400 nm can also be used, where this technique is particularly suitable for fine engraving operations.

[0028] Enamel engraving is achieved by focusing beam 8 into enamel 3 (illustrated in Figure 5B) and generating an impact matrix, while surface engraving requires focusing beam 8 near the surface to ablate the material (illustrated in Figure 5A). Typically, for enamel engraving, the wavelength is 1030 nm, i.e., in the near-infrared range; while for surface engraving, the wavelength is 515 nm, i.e., in the green range. For ultraviolet lasers, the wavelength is typically 355 nm.

[0029] Typically, the beam energy is between 10 μJ and 30 μJ, and the frequency is between 200 kHz and 1000 kHz.

[0030] For enamel surface engraving, the upper surface of the part can be engraved directly from above; however, the lower surface can also be engraved via a "bottom-up" technique. This strategy involves penetrating the transparent material without any interaction and focusing beam 8 on the lower surface to remove material, as illustrated in Figure 5C. In the case of translucent / transparent enamel, engraving on the lower surface will produce a depth effect or even a hologram on the upper surface. Materials, and especially luminescent materials, can be added to highlight the depth effect when engraving from below. In the case of laser ablation on the upper surface, an ornament made of another material (e.g., lacquer, inlaid metal, or even another enamel) can be deposited. For example, a transparent enamel matrix can be created, and then an opaque enamel can be deposited in it.

[0031] Different locations within or on the surface of enamel 3 are illustrated in Figures 4A to 4C. In Figures 4A and 4C, engraving 7 (hereinafter also referred to as a structure) is performed within the ornament 2 on one surface of enamel 3. In the example shown, ornament 2 is a through ornament. When engraving is performed on the surface, the structure can be filled with material 4, which can be, for example, a luminescent material. It can also be another enamel, such as enamel with different colors or opacities. In Figure 4B, engraving 7 is performed within enamel 3. If engraving is performed between the deposition of the various enamel layers 3 during the method for manufacturing enamel ornaments, the structure 7 can be filled with material 4. If engraving 7 is performed after the enamel layers have been deposited, the engraving will only form a structure within the enamel.

[0032] Different methods can be used to manufacture articles with enamel ornaments before or during engraving and texturing. The manufacturing method will be described below with respect to two preferred alternative embodiments that allow the production of openwork enamel ornaments with an enamel thickness of 0.5 mm or more in a short cycle time. It should be understood that other manufacturing methods are also possible.

[0033] The manufacturing method described below is suitable for any substrate with a melting point higher than the enamel firing temperature, which is typically between 650°C and 1100°C depending on the composition of the enamel. This method is particularly suitable for substrates made of hard materials, such as ceramic.Porcelain (e.g., silicon nitride, zirconium oxide, or alumina), or materials such as sapphire or cermets. Some ceramics, particularly ZrO2, have excellent mechanochemical adhesion to enamel, and their coefficients of thermal expansion are very close, which results in the perforated article maintaining excellent mechanical strength. For example, for high-temperature enamel, these materials are subjected to firing cycles up to 1000°C and resist the thermal shock of rapid firing cycles.

[0034] Figures 3A to 3E illustrate a manufacturing method according to an alternative embodiment for a pendulum hammer in five steps from a) to e). In the first step a), an article without any decoration is obtained, which will be referred to as a semi-finished product 5 or substrate. The semi-finished product is defined with an upper surface 5a and a lower surface 5b opposite to the upper surface 5a. The upper surface 5a may be the surface intended to face the observer in use or the opposite surface. In the second step b), a non-penetrating decoration 2a is produced from the upper surface 5a. The non-penetrating decoration may be produced, for example, by laser ablation. Optionally, if a semi-finished product with the non-penetrating decoration 2a is obtained directly in step a), step b) can be omitted; this semi-finished product is produced, for example, by injection molding. In the third step c), enamel 3 is deposited within the non-penetrating decoration 2a. Ideally, for industrial production, deposition is performed by liquid spraying. Alternatively, it can be deposited quickly manually with a brush or by spraying powder. The semi-finished product 5 is then fired to vitrify the deposited enamel. Preferably, multiple layers of enamel are deposited, and a firing cycle is performed after each deposition step to ensure the enamel is bubble-free. Different colors of enamel layers can be deposited and / or the color of the deposited enamel in each layer can be changed. For a total thickness greater than or equal to 0.5 mm, preferably greater than or equal to 0.8 mm, the number of deposited enamel layers is typically between 2 and 15, preferably between 3 and 10. The maximum total thickness can be up to 1.5 mm, where the maximum thickness is limited only by production time. Then, the fourth machining step d) is performed, preferably by grinding the lower surface 5b of the semi-finished product 5 to expose the enamel 3, thus obtaining the through-hole decoration 2. Then, preferably, a final polishing operation is performed to make the ground surface perfectly shiny and to ensure good transparency of the enamel. Optionally, in step e), the upper surface 5a can also be machined by grinding to obtain an enamel decoration that is perfectly flush with the substrate. Similarly, this machining can be completed by polishing. In the case of flat parts, a gem-working machine can be used to perform grinding and polishing of the top and bottom in a single operation. According to the invention, if the enamel layer has an opaque appearance before machining, the upper and / or lower surfaces can be machined in an inclined plane to obtain a translucent-opaque gradient. It should be noted that the opaque, transparent, or translucent appearance will be determined by the greater or lesser presence of pigment in the enamel and by the thickness of the layer.

[0035] Figures 1A to 1E illustrate a manufacturing method according to an alternative embodiment, consisting of six steps from a) to e), and Figure 2 shows the table frame for the table. This manufacturing method is substantially the same, except that a luminescent material is deposited on the upper surface 5a after the enamel layer has been deposited to form a backlit peep enamel ornament. In this method, the lower surface 5b is intended to be visible in use. For this reason, the lower surface 5b is shown in the upper position in the figures. However, it should be noted that, in practice, the upper surface 5a is positioned in the upper position during the enamel layer deposition step to facilitate deposition without the risk of flow.

[0036] Steps a, b, and c are the same as above. In the fourth step d), once the ornament has been at least partially filled with enamel and fired, a layer of material 4, i.e., a luminescent material, is deposited on the enamel 3 (i.e., still from the upper surface 5a of the semi-finished product). For example, the luminescent material can be a super-phosphorescent pigment added to a varnish or binder. This material provides a variety of luminescent colors, including blue, green, purple, white, yellow, orange, and pink, etc. In the fifth step e), a protective layer 6 (such as lacquer) is deposited on the luminescent material layer 4. Then, a sixth machining step f) is preferably performed by grinding on the lower surface 5b of the semi-finished product 5 to expose the enamel 3, thus obtaining a through-beam decoration 2 illuminated from the inside by the luminescent material 4. A final polishing operation can then be performed to make the polished surface perfectly shiny and to ensure good transparency of the enamel. The resulting frame is shown in Figure 2.

[0037] For the two alternative embodiments above, engraving and texturing steps can be performed during the manufacturing process, for example, between the enamel layer deposition step and the firing step.

[0038] Finally, and optionally for the two alternative embodiments of the method, in addition to laser ablation according to the invention for engraving and texturing, one or both surfaces can also be subjected to finishing treatments, such as supercalendering. Instruction Manual Page 4 / 4 7 CN 120828607 A Figure 1A Instruction Manual Figure 1 / 15 Page 8 CN 120828607 A Figure 1B Instruction Manual Figure 2 / 15 Page 9 CN 120828607 A Figure 1C Instruction Manual Figure 3 / 15 Page 10 CN 120828607 A Figure 1D Instruction Manual Figure 4 / 15 Page 11 CN 120828607 A Figure 1E Instruction Manual Figure 5 / 15 Page 12 CN 120828607 A Figure 1F Instruction Manual Figure 6 / 15 Page 13 CN 120828607 A Figure 2 Instruction Manual Figure 7 / 15 Page 14 CN 120828607 A Figure 3A Instruction Manual Figure 8 / 15 Page 15 CN 120828607 A Figure 3B DescriptionFigure 9 / 15, page 16, CN 120828607 A, Figure 3C; Figure 10 / 15, page 17, CN 120828607 A, Figure 3D; Figure 11 / 15, page 18, CN 120828607 A, Figure 3E, Figure 4A; Figure 12 / 15, page 19, CN 120828607 A, Figure 4B, Figure 4C; Figure 13 / 15, page 20, CN 120828607 A, Figure 5A, Figure 5B; Figure 14 / 15, page 21, CN 120828607 A, Figure 5C; Figure 15 / 15, page 22, CN 120828607 A. Abstract: Disclosed is an enamel engraving and texturing method. The invention relates to a method for engraving and texturing an article (1) comprising an ornament (2) at least partially filled with an enamel (3), said method comprising a step of laser ablation on the surface of the enamel (3) and / or within the enamel (3) using a femtosecond or picosecond laser to produce a structure (7).

Claims

1. A method for engraving and texturing an article (1) comprising a decoration (2) at least partially filled with enamel (3), comprising a step of laser ablation on the surface of the enamel (3) and / or in the enamel (3) using a femtosecond or picosecond laser to produce a structure (7).

2. The engraving and texturing method according to the preceding claim, wherein it involves a through-decoration (2) at least partially filled with enamel (3) to form a so-called window enamel.

3. The engraving and texturing method according to any one of the preceding claims, comprising the step of filling the structure (7) with a material (4).

4. The engraving and texturing method according to claim 1 , wherein the wavelength of the laser light is in the near infrared range, i.e. between 700 and 2500 nm; in the green range, i.e. between 510 and 560 nm; or in the ultraviolet range, i.e. between 200 and 400 nm.

5. Engraving and texturing method according to any of the preceding claims, wherein the structures (7) within the enamel (3) are obtained by focusing a laser beam (8) within the enamel (3) and by generating an impact matrix, while the structures (7) at the surface require focusing the laser beam (8) near the surface.

6. Engraving and texturing method according to the preceding claim, wherein the laser beam (8) passes completely through the enamel (3) to produce a structure (7) on the surface opposite to the point of incidence of the laser beam (8).

7. The engraving and texturing method according to any one of claims 4 to 6, wherein for the structures (7) within the enamel (3), the wavelength of the laser light is in the near infrared range; and for the structures (7) at the surface, the wavelength of the laser light is in the green range.

8. A method for manufacturing an article (1) comprising a through-going decoration (2) at least partially filled with enamel (3) to form a so-called window enamel, said method comprising the engraving and texturing steps according to any one of claims 2 to 7 and, before or during said engraving and texturing steps, the following steps: - obtaining a semi-finished product (5) defining an upper face (5a) and a lower face (5b) opposite to said upper face (5a); - removing a portion of the semi-finished product (5) from the upper face (5a) so as to produce a decoration (2a) that does not penetrate to the lower face (5b); or alternatively, in a previous step, directly obtaining the semi-finished product (5) with the non-penetrating decoration (2a); - depositing one or more layers of enamel (3) within the non-penetrating decoration (2a) and firing the enamel (3) after each layer has been deposited; - machining said lower face (5b), preferably by grinding, so as to expose said enamel (3) and thus produce an article (1) having a through decoration (2) filled with enamel (3).

9. Manufacturing method according to the preceding claim, wherein the lower face (5b) is the face intended to face the observer during use, the manufacturing method comprising a step of depositing a layer of luminescent material on the enamel (3) after the step of firing the enamel (3) and a step of depositing a protective layer (6) on the layer of luminescent material before the machining step.

10. Manufacturing method according to any one of claims 8 to 9, wherein the semi-finished product (5) is made of a material having a melting point greater than or equal to 650°C.

11. Manufacturing method according to any one of claims 8 to 10, wherein the deposit of one or more layers of enamel (3) is performed by liquid spraying, using a brush or by spraying a powder.

12. Manufacturing method according to any one of claims 8 to 11, wherein the number of layers of enamel (3) deposited is between 2 and 15, preferably between 3 and 10.

13. Manufacturing method according to any one of claims 8 to 12, wherein during the step of depositing one or more layers of enamel (3), layers of enamel (3) of different colours are deposited and / or the colour within the same layer is modulated.

14. Article (1) having a decoration (2) made of enamel (3), the decoration (2) comprising a structure (7) at the surface and / or within the enamel (3).

15. Article (1) according to the preceding claim, characterized in that The structure (7) is filled with a material (4) which is a further enamel or a material different from the enamel (3).

16. Article (1) according to the preceding claim, comprising a through-decorating decoration (2) made of empty-window enamel having a thickness of enamel greater than or equal to 0.5 mm, preferably greater than or equal to 0.8 mm.

17. Article (1) according to the preceding claim, comprising a layer of luminescent material covering the enamel (3) in the decoration (2).

18. Article (1) according to the preceding claim, the article (1) being an external timepiece component or a component of a movement.

19. Article (1) according to any one of claims 14 to 18, the article (1) being made of ceramic, preferably zirconia, sapphire or cermet.

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