Method of three-dimensionally decorating substrate to produce exterior component

Abstract

The invention relates to a method for three-dimensionally decorating a substrate for manufacturing an exterior part, comprising the steps of: depositing at least one enamel base layer on an outer surface of a ceramic substrate; firing the substrate covered with the base layer; etching the base layer in a predetermined decorative pattern so as to create one or more blind cavities extending between a bottom formed by the substrate and an opening formed by the base layer; depositing a decorative layer of a ceramic and / or metallic material on the base layer and the cavity so as to fill the cavity to form a decorative element, the material of the decorative layer being selected such that its melting point is lower than the glass transition temperature of the material constituting the base layer; performing surface treatment on the decorative layer so as to remove all layers deposited on the base layer; the substrate, the base layer, and the decorative layer are frictionally finished to remove the entire base layer.

Description

Technical Field

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

[0002] More particularly, the invention relates to a method for three-dimensional decoration of a substrate for manufacturing an external part. The method can be advantageously applied to any external part in the field of watchmaking, jewellery or fashion items such as leather goods, spectacles, writing instruments or portable electronic devices. Background Art

[0003] In the field of watchmaking, there are many methods for producing a raised decoration on the surface of a substrate in order to form an external part such as a dial, a plate, a bridge, a gear train, an oscillating weight, a bezel, a middle part, a bracelet link or a bracelet clasp.

[0004] Among these methods, there is a method of producing a mask on a substrate, the mask comprising openings whose contours correspond to the shape of the element to be decorated. These openings are filled with the material constituting the decorative element, and the mask is then removed.

[0005] Although simple, this method has a number of disadvantages. More specifically, in some cases the mask may not be in close contact with the surface of the substrate, which may lead to problems in meeting manufacturing tolerances for the decoration.

[0006] Another disadvantage is that this method requires the deposition of the decorative element without damaging the mask, in which case manufacturing tolerances will be compromised, and the mask needs to be removed without damaging the substrate and the decoration. Therefore, this method offers very little freedom in terms of the materials that can be used to manufacture the substrate and the decoration. Summary of the invention

[0007] The present invention overcomes the above mentioned drawbacks by providing a solution which ensures that manufacturing tolerances of the decoration are not compromised and that the mask is held in place when the decorative element is deposited and that the integrity of the substrate and the decoration is not compromised when the mask is removed.

[0008] To this end, the invention relates to a method for three-dimensionally decorating a substrate for producing an exterior component, the method comprising the following steps:

[0009] - depositing at least one enamel base layer on the outer surface of the ceramic substrate;

[0010] - firing the substrate covered with the base layer;

[0011] - etching the base layer in a predetermined decorative pattern so as to produce one or more blind cavities extending between a bottom formed by the substrate and an opening formed by the base layer;

[0012] - depositing a decorative layer of ceramic material and / or metallic material on said substrate and said cavity so as to fill said cavity and thereby form a decorative element;

[0013] - surface treatment of said decorative layer in order to remove all said layer deposited on said base layer;

[0014] - Friction finishing of the substrate and the base layer and the decorative layer to remove the entire base layer.

[0015] In a specific embodiment, the present invention may also include one or more of the following features taken alone or in any combination that is technically possible.

[0016] In a particular embodiment, the substrate is surface treated after the firing step.

[0017] In a particular embodiment, the decorative layer is deposited so that its thickness in the cavity is greater than or equal to the thickness of the decorative element at the end of the method.

[0018] In a particular embodiment, the base layer is made of borosilicate enamel.

[0019] In a specific embodiment, the base layer is made of sodium borosilicate enamel.

[0020] In a particular embodiment, during the firing step, the substrate covered with the base layer is subjected to a temperature comprised between 500°C and 1500°C, preferably substantially equal to 1000°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other characteristics and advantages of the present invention will become apparent from the following detailed description, given by way of example and not limiting in any way, with reference to the accompanying drawings, in which:

[0022] Figures 1a to 1f Schematically shown are cross-sectional views of the steps involved in carrying out a method for decorating a substrate for manufacturing an exterior component according to a preferred exemplary embodiment of the present invention.

[0023] It should be noted that for the sake of clarity, the drawings are not necessarily drawn to scale. DETAILED DESCRIPTION

[0024] The invention relates to a method for three-dimensionally decorating a substrate 11 in order to manufacture an external part 10, such as Figures 1a to 1f Shown continuously in .

[0025] The method first comprises the step of depositing at least one enamel base layer 12 on the outer surface 110 of the ceramic substrate 11, such as Figure 1a As shown. Once the outer part 10 has been manufactured, the outer surface 110 is intended to be visible to the user. Preferably, the base layer 12 is deposited over the entire outer surface 110 .

[0026] In a preferred exemplary embodiment of the present invention, the base layer 12 is made of borosilicate enamel, in particular sodium borosilicate enamel, for reasons that will be described in detail below. The base layer 12 can be applied by dipping, spraying or brushing. In this document, for reasons of language and simplified reading, the singular is used when referring to the base layer 12, but the base layer 12 can be composed of a stack of layers.

[0027] Advantageously, the substrate 11 may be made of any dense ceramic such as zirconium oxide, aluminum oxide, yttrium aluminum garnet (also known as "YAG"), sapphire or a mixture of these elements.

[0028] The base layer 12 and the substrate 11 are then fired in a furnace at a temperature between 500 and 1500 degrees Celsius, preferably 1000 degrees Celsius, so that the base layer 12 melts and chemically adheres to the substrate 11. Due to its composition, the adhesion of the base layer 12 to the substrate 11 is guaranteed after this step.

[0029] The base layer 12 is preferably surface treated after the firing step in order to flatten its visible surface and make its thickness uniform. Figure 1a As shown in an exaggerated manner, the thickness of the base layer 12 may vary. In particular, due to surface tension phenomena occurring during the firing of the base layer 12, the surface of the base layer 12 may have a series of depressions and protrusions, and due to the wettability of the layer, the thickness of the base layer 12 may be greater at the center of the outer surface 110 than at its periphery. Furthermore, if the outer surface 110 does not extend horizontally, i.e. forms a slope, the base layer 12 may have a tendency to flow in the direction of the slope during firing and thus develop an excessive thickness under the action of gravity and due to its thermal viscosity.

[0030] The substrate 12 is preferably surface treated by mechanical abrasion (eg by grinding or sanding). Figure 1b is schematically shown in FIG.

[0031] The base layer 12 is then etched according to a predetermined decorative pattern. More specifically, the purpose of this etching step is to create one or more blind cavities 120 in the base layer 12 in order to accommodate a raised decorative element 130, as discussed in more detail below. The cavity 120 extends between a bottom formed by the substrate 11 and an opening formed by the base layer 12, as shown in FIG. Figure 1cThe surface treatment step, after which the visible surface of the base layer 12 is flattened, makes it possible to control the manufacturing tolerances of the cavity 120 .

[0032] Advantageously, the cavity 120 may also extend into the substrate 11, such as Figure 1c to Figure 1f This feature further increases the adhesion of the decorative element 130 within the substrate 11 .

[0033] Preferably, the etching step is performed by laser, but may be performed by any suitable technical solution, such as by machining.

[0034] Then, if Figure 1d As shown, a decorative layer 13 is deposited on the base layer 12 and in the cavity 120. Depending on the material envisaged for the decorative layer 13, such a decorative layer 13 can be deposited by spraying, pressing, thermal and plasma spraying or sliding deposition. In particular, the decorative layer 13 can be made of a ceramic material, such as an enamel, such as a borosilicate enamel or feldspar, and / or can be made of a metallic material. In this context, the term "metallic material" refers to any metal alloy, any pure metal or any metal composite material.

[0035] 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 depositing the decorative layer 13. For example, the melting point of the material constituting the base layer 12 is lower than 600°C.

[0036] The decorative layer 13 is deposited so 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.

[0037] After the decorative layer 13 has been deposited, a surface treatment step is performed in order to remove all of said decorative layer 13 deposited on the base layer 12, such as Figure 1e This surface treatment operation is advantageously performed by mechanical abrasion, for example by grinding or sanding.

[0038] Once the decorative layer 13 is present only in the cavity 120, a friction finishing step is performed to remove the entire base layer 12 and form the external part 10. Advantageously, due to the material of the base layer 12, it is very easily and quickly removed by the friction finishing step, without abrasive elements causing uncontrolled damage to the outer surface 110 of the substrate 11 or to the decorative element 130 formed by the remains of the decorative layer 13.

[0039] Figure 1f The outer component 10 and the potential effect of the friction finishing step on the decorative element 130 are schematically shown. In particular, sharp edges of the decorative element 130 may be rounded by the abrasion caused during the friction finishing step.

[0040] The material of the decorative layer 13 is selected to withstand the friction finishing step better than the sacrificial base layer 12 .

[0041] More generally, it should be noted that the embodiments and examples considered above have been described by way of non-limiting examples and that other alternatives are therefore possible.

Claims

1. A method for three-dimensionally decorating a substrate (11) to produce an exterior component (10), the method comprising the following steps: - depositing at least one enamel base layer (12) on the outer surface (110) of the ceramic substrate (11); - firing the substrate (11) covered with the base layer (12); - etching the base layer (12) in a predetermined decorative pattern so as to produce one or more blind cavities (120) extending between a bottom formed by the substrate (11) and an opening formed by the base layer (12); - depositing a decorative layer (13) of ceramic and / or metallic material on the base layer (12) and the cavity (120) so as to fill the cavity (120) and thereby form a decorative element (130), the material of the decorative layer (13) being chosen such that its melting point is lower than the glass transition temperature of the material constituting the base layer (12); - surface treatment of the decorative layer (13) in order to remove all of the layer deposited on the base layer (12); - Friction finishing the substrate (11), the base layer (12) and the decorative layer (13) to remove the entire base layer (12).

2. The method according to claim 1, wherein: The substrate (12) is surface treated after the firing step.

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

4. The method according to any one of claims 1 to 3, wherein: The base layer (12) is made of borosilicate enamel.

5. The method according to claim 4, wherein: The base layer (12) is made of sodium borosilicate enamel.

6. The method according to any one of claims 1 to 5, wherein: During said firing step, said substrate (11) covered with said base layer (12) is subjected to a temperature between 500°C and 1500°C, preferably substantially equal to 1000°C.

Images