METHOD FOR MANUFACTURING APPLICATIONS ON A DIAL

Description

Object of the invention

[0001] The present invention relates to a method for manufacturing appliqués on a dial for a timepiece. Technological background

[0002] The present invention aims to improve the processes of depositing decorative patterns on the surface of a watch component.

[0003] A watch dial typically features decorative appliqués. These appliqués might, for example, represent an hour marker to help determine the time by aligning it with the position of the watch hands. They can also be used simply to enhance the dial's aesthetic appeal.

[0004] Typically, these appliqués are mounted on the dial through successive stages of gluing, followed possibly by masking and / or swabbing. This, in addition to the cost of the appliqués themselves, results in increased manufacturing costs due to the required positioning precision, which is greater the thicker the appliqué. Document EP 2 182 096 A1 describes a process for manufacturing metal parts on a substrate for watch components, comprising the following steps: provide a substrate, the substrate having a front face and a back face; perform a surface preparation of the front face, then selectively structure the front face and deposit at least one layer on it; deposit a first protective layer all around the dial having at least one layer; machine at least one recess in the first protective layer to form a mold for the future appliques; fill said at least one recess by electroplating from the substrate with a material to form the metal parts; remove the first protective layer; deposit a second protective layer on the front face of the substrate to cover the front face of the substrate and the metal parts; polish the second protective layer and the metal parts to a predetermined height; remove the second protective layer. Summary of the invention

[0005] The present invention relates to a method for manufacturing appliqués on a dial for a timepiece, comprising the following steps: a) provide a dial, the dial having a front face and a back face; b) perform surface preparation of the front face; c) apply a first protective layer all around the dial, which has at least one decorative layer; d) machine at least one recess in the first protective layer and the decorative layer to form a mold for the future appliqués, and drill the dial to form at least one attachment point; e) fill said at least one recess by electroplating from the dial with a material to form the appliqués; f) remove the first protective layer; g) apply a second protective layer to the front face of the dial to cover the dial and the appliqués; h) cut the dial to the desired dimensions and polish the second protective layer and the appliqués to a predetermined height; i) perform a selective surface treatment on the top of the appliqués;j) Remove the second protective layer.

[0006] In accordance with other advantageous variants of the invention: The dial is made of a material selected from copper alloys, iron alloys, gold alloys, or silver alloys; the decorative layer is made of a material selected from silver, gold, copper, nickel, rhodium, or ruthenium; the first and second protective layers are resin-based; the resin is selected from acrylic resins, nitrocellulose resins, alkyd resins, or polyurethane resins; the material filling at least one recess is selected from silver, gold, copper, nickel, rhodium, or ruthenium; the first and second protective layers are removed using a solvent or plasma; the engraving of at least one recess is carried out by a laser engraving process that allows the decorative layer to be engraved. and the first protective layer; In step b), the surface preparation of the face consists of polishing, sanding and / or sandblasting the front face of the dial in a dry or wet environment. In step b), the surface treatment of the front face is an operation of microblasting, sunburst finishing, guilloché engraving, engraving, milling, spiraling, rimming, beading or any other operation allowing to obtain a decorative structure. Brief description of the figures

[0007] THE figures 1 to 10 represent the successive stages of a preferred example of a decoration process according to the invention. Detailed description of the invention

[0008] The process according to the invention will be better understood in relation to the figures 1 to 10 In a first step a) illustrated in the figure 1 The method according to the invention consists of providing a dial 1 comprising a front face 10 and a rear face 11, the front face being intended to receive the appliques.

[0009] Preferably according to the invention, the dial is formed from a material chosen from copper alloys, iron alloys, gold alloys or silver alloys.

[0010] Of course, as an alternative to using a dial made of electrically conductive material, it is also possible to use a dial made of any material coated with an electrically conductive layer. For example, one could imagine a ceramic dial coated with a layer of silver.

[0011] As illustrated in the figure 2 , the second step b) of the process consists of first preparing the front face 10, then selectively structuring the front face 10 in order to locally modify the surface condition and finally depositing at least one layer of decoration 2 over the entire dial.

[0012] Surface preparation of the front face 10 involves polishing, sanding and / or sandblasting the front face of the dial in a dry or wet environment. Plasma or laser treatment is also possible.

[0013] The structuring of the dial's front face is a classic watchmaking decoration technique. This structuring involves various methods, such as microblasting, sunburst finishing, guilloché engraving, engraving, milling, spiraling, circular graining, perlage, or any other technique that creates a decorative pattern. This step serves both to decorate the dial and to enhance the surface's adhesion for the decorative layer.

[0014] The second decorative layer is made of a material chosen from silver, gold, copper, nickel, rhodium, ruthenium or any other possible coatings that can be obtained by wet (chemical or electrolytic deposition) or dry (spraying, PVD) means.

[0015] Optionally, to improve the mechanical stability of the interface between the decoration layer 2 and the dial 1, an intermediate adhesive layer can advantageously be deposited between the decoration layer 2 and the dial 1. For example, titanium generally exhibits adequate adhesion to most common substrates. The thickness of this layer can be extremely small: a few nanometers are usually sufficient to significantly improve adhesion.

[0016] The metallic layer deposited on the dial surface has good adhesive properties to promote the adhesion of the applied elements. The layer material can be titanium, nickel, gold, or another material and / or a combination of several layers.

[0017] Preferably, the decorative layer is made by physical vapor deposition (PVD), however, other types of deposition are conceivable such as electroplating, chemical vapor deposition (CVD) or atomic layer deposition (ALD).

[0018] As illustrated in the figure 3The third step (c) of the process consists of completely coating the dial with a polymer layer 3 by spraying, immersion, or spin coating, and then curing the resin 3 using heat or UV light. Naturally, the layer thickness will depend on the desired size of the appliques; preferably, the layer thickness is between 0.02 mm and 0.40 mm.

[0019] Resin 3 is chosen from acrylic resins, nitrocellulose resins, alkyd resins or polyurethane resins.

[0020] As an alternative, it is possible to completely cover the dial 1 with resin 3, then to polymerize it, and to machine the top of the resin layer to make its upper part perfectly flat.

[0021] As illustrated in the figure 4The fourth step (d) of the process consists of machining at least one recess 4 in the protective layer and the decorative layer to form a mold for the future appliqués. During this step, the dial is also drilled in several places to form at least one attachment point 5 for the galvanic growth in the following step.

[0022] Advantageously, at least one recess 4 is formed by a laser process or by photolithography using a positive or negative resin, in order to easily control the geometry of the future appliqué, to make recesses 4 having walls essentially perpendicular to the surface of the dial 1, to quickly engrave many parts, and finally, to finely control the surface condition of the engraved area.

[0023] As illustrated in the figure 5, the fifth step e) of the process consists of depositing a material by electroplating from the front face 10 of the electrically conductive dial 1 in order to form in a single step at least one appliqué 6. The dial 1 is immersed in a galvanic bath by means of at least one attachment point 5 which also allows the dial 1 to be used as a cathode.

[0024] The material used to fill at least one recess 4 and form the appliqué 6 on the dial 1 is chosen from silver, gold, copper, nickel, rhodium or ruthenium.

[0025] The material used to form the applique 6 may be different from that used for the decorative layer depending on the desired aesthetic result.

[0026] As illustrated in the figure 6The sixth step (f) of the process consists of freeing the dial 1 from the first layer of resin 3 by dissolution, pickling, or plasma. Preferably, an organic solvent suitable for the deposited resin is used to remove the first protective layer.

[0027] As illustrated in the figure 7 The seventh step (g) of the process consists of coating the front face 10 of the dial 1 with a second protective layer of resin 7 by spraying, and then polymerizing the resin 7 using heat or UV rays. The thickness of this second layer of resin is at least equal to the height of the appliqués 6 formed during step (e), and preferably greater than the height of the appliqués 6.

[0028] The resin 7 forming the second protective layer is chosen from acrylic resins, nitro-cellulosic resins, alkyd resins or polyurethane resins.

[0029] As illustrated in the figure 8The eighth step h) of the process consists first of all in machining the dial 1 to the dimensions and shape desired, then polishing the protective resin layer 7 and the appliqués 6 to a predetermined height.

[0030] As illustrated in the figure 9 , the ninth step i) of the process consists of performing a selective surface treatment on the top of the appliques 6.

[0031] Selective surface treatment consists of the deposition of a metallic layer 8 by physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD) or by wet process (galvanic treatment).

[0032] As illustrated in the Figure 10 , the tenth and final step j) of the process consists of removing the second protective layer and freeing the dial 1 fitted with its appliques 6.

[0033] Feet can be welded to the dials at various stages of the production process to facilitate handling of the parts and / or to meet product specifications. These feet can serve as contact points for applying coatings 2 or for forming appliqués 6 by electroforming. In the latter case, these feet are used instead of the holes 5.

[0034] It is therefore understood that the process, advantageously according to the invention, allows the use of the advantages of machining, photolithography and electroplating to electroform in a single electroplating step the appliqués on a dial with very good structural precision.

[0035] Of course, the present invention is not limited to the illustrated example but is susceptible to various variants and modifications which will become apparent to those skilled in the art.

[0036] Furthermore, the preferred methods or variations of the process according to the invention are used solely to illustrate an embodiment of the invention and are not limited to them. Thus, other materials or other material removal or structuring processes may be considered.

Claims

1. Method for manufacturing appliques (6) on a dial (1) for a timepiece, characterised in that it comprises the following steps of: a) providing a dial (1), the dial having a front face (10) and a rear face (11); b) carrying out a surface preparation treatment on the front face (10), then selectively structuring the front face and depositing thereon at least one decorative layer (2); c) depositing a first protective layer (3) all around the dial provided with the at least one decorative layer; d) machining at least one recess (4) in the first protective layer (3) and the decorative layer (2) to form a mould for future appliques, and boring the dial (1) to form at least one adhesion point (5); e) filling said at least one recess (4) with a material by electroplating on the dial (1) to form the appliques (6); f) removing the first protective layer (3); g) depositing a second protective layer (7) on the front face (10) of the dial (1) to cover the front face of the dial and the appliques (6); h) cutting the dial (1) to the desired dimensions and polishing the second protective layer (7) and the appliques (6) over a predetermined height; i) carrying out a selective surface treatment on the tip of the appliques (6); j) removing the second protective layer (7).

2. Method according to claim 1, wherein the dial (1) is made of a material selected from copper alloys, iron alloys, gold alloys or silver alloys.

3. Method according to claim 1 or 2, wherein the decorative layer (2) is made of a material selected from silver, gold, copper, nickel, rhodium or ruthenium.

4. Method according to one of the preceding claims, wherein the first protective layer and the second protective layer are resin-based.

5. Method according to claim 4, wherein the resin is selected from acrylic resins, nitro-cellulosic resins, alkyd resins or polyurethane resins.

6. Method according to one of claims 1 to 5, wherein said material filling the at least one recess is selected from silver, gold, copper, nickel, rhodium or ruthenium.

7. Method according to one of the preceding claims, wherein the decorative layer (2) comprises an adhesive layer preferably comprising titanium.

8. Method according to one of claims 1 to 7, wherein the first and second protective layers are removed by means of a solvent.

9. Method according to one of the preceding claims, wherein the etching of the at least one recess (4) is carried out by a laser etching method allowing the decorative layer (2) and the first protective layer (3) to be etched.

10. Method according to any one of the preceding claims, wherein in step b), the surface preparation of the face consists of polishing, pumicing and / or sanding the front face of the dial.

11. Method according to any one of the preceding claims, wherein in step b), the surface treatment of the front face is a shot-blasting, sunbursting, engine-turning, etching, milling, snailing, or circular graining operation.