Method for three-dimensionally decorating substrate in order to manufacture external component

Abstract

To provide a method for manufacturing an external component including a decoration raised on a surface of a substrate.SOLUTION: A method for three-dimensionally decorating an external component 10 includes the steps of: depositing at least one enamel base layer 12 on an external surface 110 of a ceramic substrate 11; firing the substrate 11 covered with the base layer; etching the base layer in a prescribed decoration pattern so as to generate one or more blind cavities; filling the cavities by depositing a decorative layer of a ceramic material and / or metallic material on the base layer and the cavities to form decorative elements 130, thereby, wherein the material of the decorative layer is selected so that a melting point thereof is lower than a glass-transition temperature of a material constituting the base layer; removing all the layers deposited on the base layer by subjecting the decorative layer to surface treatment; and tribofinishing the substrate 11, the base layer and the decorative layer in order to remove the whole base layer.SELECTED DRAWING: Figure 1f

Description

[Technical field]

[0001] The present invention relates to the decoration of watches, jewellery or fashion items, in particular the manufacture of external parts.

[0002] In particular, the present invention relates to a method for three-dimensional decoration of a substrate to manufacture an external part, which can be advantageously applied to any external part in the field of watchmaking, jewellery or fashion items such as leather goods, glasses, writing implements or portable electronic devices. [Background technology]

[0003] In the field of watchmaking, there are many methods for producing raised ornamentation on the surface of a substrate to form external parts such as dials, plates, bridges, gear trains, oscillating weights, bezels, middle sections, bracelet links or bracelet clasps.

[0004] Among these methods, a mask is produced on the substrate, which contains a number of openings whose contours correspond to the shape of the desired decorative element, which openings are filled with the material that constitutes the decorative element, and then the mask is removed.

[0005] Although this method is simple, it has certain drawbacks: in particular, in some cases the mask may not adhere closely to the surface of the substrate, which can lead to problems in meeting the manufacturing tolerances of the decoration.

[0006] Another drawback is that this method requires that the mask not be damaged by the deposition of the decorative elements, which does not respect manufacturing tolerances and requires that the mask be removed without damaging the substrate and the decoration, i.e. the method offers very little freedom with regard to the materials that can be used to make the substrate and the decoration. Summary of the Invention

[0007] The present invention overcomes the above mentioned drawbacks by providing a solution that ensures that the manufacturing tolerances of the decoration are respected and that the mask is held in place when the decorative elements are being deposited, and also ensures that the integrity of the substrate and the decoration is respected when the mask is being removed.

[0008] To this end, the present invention relates to a method for three-dimensional decoration of a substrate for the production of an external component, the method comprising: depositing at least one enamel base layer on an outer surface of the ceramic substrate; - firing the substrate covered by the base layer; - etching the base layer with a predetermined decorative pattern to create one or more blind cavities extending between a bottom defined by the substrate and an opening defined by the base layer; depositing a decorative layer of ceramic and / or metallic material on the base layer and on the cavity to form a decorative element and fill said cavity; a surface treatment of the decorative layer to remove all of said layers deposited on the base layer; - subjecting the substrate, base layer and decorative layer to a rubbing finish to remove the entire base layer; Includes.

[0009] In particular implementations, the present invention may further include one or more of the following features, taken alone or in any technically possible combination.

[0010] In certain implementations, the base layer is surface treated after the firing step.

[0011] In a particular implementation, the decorative layer is deposited such that its thickness in the cavity is equal to or greater than the thickness of the decorative element at the end of the method.

[0012] In a particular implementation, the base layer is made from borosilicate enamel.

[0013] In a particular implementation, the base layer is made from sodium borosilicate enamel.

[0014] In a particular implementation, the temperature to which the substrate covered by the base layer is exposed during the firing step is between 500°C and 1500°C, preferably substantially equal to 1000°C. [Brief description of the drawings]

[0015] Other characteristics and advantages of the invention will become apparent from the following detailed description, given by way of example and not of limitation, with reference to the accompanying drawings, in which:

[0016] [Figure 1a] Figures 1a to 1f show diagrammatically cross-sectional views of the steps involved in carrying out a method of decorating a substrate to manufacture an external component according to a preferred embodiment of the invention. [Figure 1b] Figures 1a to 1f show diagrammatically cross-sectional views of the steps involved in carrying out a method of decorating a substrate to manufacture an external component according to a preferred embodiment of the invention. [Figure 1c] Figures 1a to 1f show diagrammatically cross-sectional views of the steps involved in carrying out a method of decorating a substrate to manufacture an external component according to a preferred embodiment of the invention. [Figure 1d] Figures 1a to 1f show diagrammatically cross-sectional views of the steps involved in carrying out a method of decorating a substrate to manufacture an external component according to a preferred embodiment of the invention. [Figure 1e] Figures 1a to 1f show diagrammatically cross-sectional views of the steps involved in carrying out a method of decorating a substrate to manufacture an external component according to a preferred embodiment of the invention. [Figure 1f] Figures 1a to 1f show diagrammatically cross-sectional views of the steps involved in carrying out a method of decorating a substrate to manufacture an external component according to a preferred embodiment of the invention.

[0017] It should be noted that for purposes of clarity, the drawings have not necessarily been drawn to scale. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The invention relates to a method for three-dimensional decoration of a substrate 11 to manufacture an external part 10, as shown in the sequence of Figures 1a to 1f.

[0019] The method first involves depositing at least one enamel base layer 12 onto an exterior surface 110 of a ceramic substrate 11, as shown in Figure 1a. The exterior surface 110 is intended to be visible to a user once fabrication of the exterior component 10 is complete. Preferably, the base layer 12 is deposited over the entire exterior surface 110.

[0020] In a preferred implementation of the invention, the base layer 12 is made from borosilicate enamel, specifically sodium borosilicate enamel, for reasons detailed below. The base layer 12 may be applied by dip coating, spraying, or brushing. For linguistic reasons and readability, the singular form is used herein when referring to the base layer 12, although the base layer 12 may be comprised of a stack of multiple layers.

[0021] Advantageously, the substrate 11 is made from any dense ceramic such as zirconia, alumina, yttrium aluminum garnet (also known by the acronym "YAG"), sapphire, or a mixture of these elements.

[0022] The base layer 12 and the substrate 11 are then baked in an oven at a temperature between 500 and 1500 degrees Celsius, preferably at 1000 degrees Celsius, causing the base layer 12 to melt and chemically bond to the substrate 11. Due to its composition, the adhesion of the base layer 12 to the substrate 11 is guaranteed after this step.

[0023] The base layer 12 is preferably surface-treated after the firing step to flatten its visible surface and make its thickness uniform. In particular, as shown in an exaggerated manner in FIG. 1a, the base layer 12 is prone to variations in thickness. In particular, since the surface of the base layer 12 may have successive depressions and bulges due to surface tension phenomena occurring during firing of the base layer 12, the thickness of the base layer 12 may be greater in the center of the outer surface 110 than at its periphery due to the wettability of the layer. Furthermore, if the outer surface 110 does not extend horizontally, i.e. forms a slope, the base layer 12 may tend to flow in the direction of the slope during firing, resulting in excessive thickness under the effect of gravity and due to its high-temperature viscosity.

[0024] The base layer 12 is preferably surface treated by mechanical abrasion, for example by grinding or sanding. The result of this step is shown diagrammatically in Figure 1b.

[0025] The base layer 12 is then etched according to a predetermined decorative pattern. In detail, the purpose of this etching step is to generate one or more blind cavities 120 in the base layer 12 to accommodate raised decorative elements 130, as will be explained in more detail below. The cavities 120 extend between the bottom formed by the substrate 11 and the opening formed by the base layer 12, as shown in Fig. 1c. A surface processing step makes it possible to control the manufacturing tolerances of the cavities 120. After the surface processing step, the visible surface of the base layer 12 is planned.

[0026] Advantageously, the cavity 120 may extend into the substrate 11, as shown in Figures 1c to 1f. This feature further enhances the adhesion of the decorative element 130 within the substrate 11.

[0027] Preferably, the etching step is carried out by means of a laser, but it may also be carried out by any suitable technical solution, for example by machining.

[0028] A decorative layer 13 is then deposited on the base layer 12 and in the cavity 120, as shown in Fig. 1d. Such a decorative layer 13 may be deposited by spraying, pressing, thermal and plasma spraying or slip deposition, depending on the material envisaged for the decorative layer 13. In particular, the decorative layer 13 may be made of a ceramic material, for example an enamel such as a borosilicate enamel or a feldspar, and / or of a metallic material. In this specification, the term "metallic material" refers to any metal alloy, any pure metal or any metallic composite.

[0029] The material constituting the decorative layer 13 advantageously has a melting point lower than the glass transition temperature of the material constituting the base layer 12, so that the base layer 12 is not damaged when the decorative layer 13 is being deposited. By way of example, the melting point of the material constituting the base layer 12 is below 600 degrees Celsius.

[0030] The decorative layer 13 is deposited such that its thickness in the cavity 120 is greater than or equal to the desired thickness of the decorative element 130 at the end of the method.

[0031] After the decorative layer 13 has been deposited a surface treatment step is performed in which all of said decorative layer 13 deposited on the base layer 12 is removed, as shown in Figure 1e. Such a surface treatment operation is advantageously performed by mechanical abrasion, for example grinding or sanding.

[0032] Once the decorative layer 13 is only present in the cavities 120, a rubbing step is performed to remove the entire base layer 12 and form the exterior part 10. Advantageously, thanks to the material of the base layer 12, this base layer is very easily and quickly removed by the rubbing step without the abrasive elements causing uncontrollable damage to the exterior surface 110 of the substrate 11 or to the decorative elements 130 formed by the remains of the decorative layer 13.

[0033] Figure 1f shows diagrammatically this external part 10 and the potential effect of a rubbing finishing step on the decorative element 130. In particular, sharp edges of the decorative element 130 are rounded off by the wear caused during the rubbing finishing step.

[0034] The material of the decorative layer 13 is selected to withstand the rub-finishing step better than the base layer 12, which is sacrificial.

[0035] In general, it should be noted that the implementations and embodiments considered above are described as non-limiting examples, and therefore other alternatives are possible.

Claims

1. A method for three-dimensional decoration of a substrate (11) for producing an external part (10), comprising the steps of: - depositing at least one enamel base layer (12) on the outer surface (110) of the ceramic substrate (11); - firing the substrate (11) covered by the base layer (12); etching said base layer (12) with a predetermined decorative pattern to create one or more blind cavities (120) extending between a bottom defined by said substrate (11) and an opening defined by said base layer (12); - depositing a decorative layer (13) of ceramic and / or metallic material on said base layer (12) and on said cavity (120) to form a decorative element (130) and to fill said cavity (120), the material of said decorative layer (13) being chosen such that its melting point is below the glass transition temperature of the material constituting said base layer (12); - surface treatment of said decorative layer (13) to remove all of said layers deposited on said base layer; - subjecting the substrate (11), the base layer (12) and the decorative layer (13) to a rubbing finish to remove the entire base layer (12); A method comprising:

2. The method of claim 1 , wherein the base layer (12) is surface treated after the firing step.

3. 2. The method according to claim 1, wherein the decorative layer (13) is deposited such that its thickness in the cavity (120) is equal to or greater than the thickness of the decorative element (130) at the end of the method.

4. The method of claim 1 , wherein the base layer (12) is made from borosilicate enamel.

5. The method of claim 4, wherein the base layer (12) is made from sodium borosilicate enamel.

6. 2. The method according to claim 1, wherein the temperature to which the substrate (11) covered by the base layer (12) is subjected during the firing step is between 500°C and 1500°C, preferably substantially equal to 1000°C.

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