CH721050A2 - Three-dimensional decoration process of a substrate in order to produce a covering part - Google Patents

Abstract

The invention relates to a method for three-dimensional decoration of a substrate (11) in order to produce a decorative part (10) comprising the steps of: – depositing at least one support layer (12) of enamel on a decorative zone of a decorative surface (110) of a substrate (11) made of ceramic, said decorative zone being intended to receive a decorative element (13); – firing the substrate (11) comprising the support layer (12) so as to cause the latter to melt; – depositing a decorative element (13) of ceramic and/or metal in solid form on the support layer (12); – sealing the decorative element (13) on the substrate (11) by firing so as to form a decorative part (10). The invention relates to the field of decoration of timepieces, jewelry or fashion items.

Description

Technical field of the invention

[0001] The invention relates to the field of decoration of timepieces, jewelry or fashion items, and in particular the manufacture of decorative items.

[0002] More particularly, the invention relates to a method for three-dimensional decoration of a substrate in order to produce a decorative part. This method can be advantageously applied to any decorative part in the field of watchmaking, jewelry, fashion articles such as leather goods, eyewear, writing instruments or portable electronic devices.

Technological background

[0003] In the aforementioned fields, the cladding parts can be formed by assembling elements made of different materials. In particular, cladding parts comprising a metallic and/or ceramic decorative element fixed to a ceramic substrate are particularly attractive, although uncommon due to the complexity of their manufacture.

[0004] Indeed, the very small dimensions of the decorative elements make it difficult to grip them and position them on the substrate.

[0005] Another disadvantage of this type of assembly part comes from the fact that the durability of the connection between the decorative element and the substrate is not controlled, since the decorative element is fixed to the substrate by driving, gluing or screwing.

Summary of the invention

[0006] The invention solves the aforementioned drawbacks by proposing, for this purpose, a Method for three-dimensional decoration of a substrate in order to produce a cladding part comprising the steps of: – depositing at least one enamel support layer on a decorative zone of a cladding surface of a substrate made of ceramic, said decorative zone being intended to receive a decorative element; – firing the substrate comprising the support layer so as to cause the latter to melt; – depositing a decorative element made of ceramic material and/or metallic material in solid form on the support layer, the material of which is chosen so that its melting temperature is higher than the glass transition temperature of the material constituting the support layer; – sealing the decorative element on the substrate by firing so as to form a cladding part.

[0007] In particular embodiments, the invention may further comprise one or more of the following characteristics, taken in isolation or in all technically possible combinations.

[0008] In particular embodiments, the baking of the substrate and the support layer and the sealing of the decorative element on the substrate are carried out in the same step, when the melting temperature of the material constituting the decorative element is greater than 1000 degrees Celsius.

[0009] In particular embodiments, a blind cavity is made in the substrate so as to form the decorative zone and so that its shape corresponds to the shape of the decorative element, the latter being deposited so as to extend beyond said cavity.

[0010] In particular embodiments, the cavity has a depth of at least 0.01 mm, preferably 0.1 mm.

[0011] In particular embodiments, the support layer is made of borosilicate enamel or feldspar.

[0012] In particular embodiments, the support layer is made of sodium borosilicate enamel.

[0013] In particular embodiments, when the melting temperature of the material constituting the decorative element is less than 1000 degrees Celsius, following the step of baking the substrate comprising the support layer, the latter is surfaced so as to flatten its surface and so as to equalize its thickness.

[0014] In particular embodiments, during the sealing step the temperature to which the substrate, the support layer and the decorative element are subjected is between 500 degrees Celsius and 1500 degrees Celsius.

Brief description of the figures

[0015] Other characteristics and advantages of the invention will appear on reading the following detailed description given by way of non-limiting example, with reference to the appended drawings in which: – Figures 1a to 1c schematically represent a sectional view of the steps of carrying out a method of decorating a substrate for producing a covering part according to a first alternative embodiment of the invention; – Figures 1d to 1f schematically represent a sectional view of the steps of carrying out a method of decorating a substrate for producing a covering part according to a second alternative embodiment of the invention.

[0016] Note that the figures are not necessarily drawn to scale for reasons of clarity.

Detailed description of the invention

[0017] The present invention relates to a method for three-dimensional decoration of a substrate 11 in order to produce a covering part 10 as shown in two variant embodiments in FIGS. 1c and 1f. More particularly, the steps of a first variant implementation of the method are schematically shown in FIGS. 1a to 1c, and are described firstly below. The steps of a second variant implementation of the method are schematically shown in FIGS. 1d to 1f, and are described secondly.

[0018] By way of example, in the field of watchmaking, the exterior part 10 can form a dial, a plate, a bridge, a gear train, an oscillating weight, a bezel, a case middle, links of a bracelet or a clasp of a bracelet.

[0019] In the first implementation variant, the method comprises a step of depositing at least one enamel support layer 12 on a decorative area of a covering surface 110 of a substrate 11, as shown in FIG. 1a. The covering surface 110 is intended to be visible to a user once the covering part 10 has been produced. Furthermore, the decorative area constitutes a flat portion of the covering surface 110 and is intended to receive a decorative element, as described in more detail below.

[0020] In this variant implementation of the invention, the support layer 12 is made of borosilicate enamel, for example sodium borosilicate, or feldspar. In the present text, by abuse of language and to simplify reading, the singular is used when referring to the support layer 12, however the support layer 12 may be composed of a stack of layers.

[0021] Advantageously, the substrate 11 is made of ceramic, for example a dense ceramic, such as zirconia, alumina, yttrium aluminum garnet also known by the acronym “YAG” meaning Yttrium Aluminum Garnet, sapphire or a mixture of these elements.

[0022] The substrate 11 and the support layer 12 are then baked in an oven at a temperature between 500 and 1500 degrees Celsius, preferably at 1000 degrees Celsius, so as to cause the support layer 12 to melt and chemically adhere to the substrate 11. Thanks to its composition, the adhesion of the support layer 12 to the substrate 11 is guaranteed following this step.

[0023] The support layer 12 is preferably surfaced following the baking step, as schematically illustrated in FIG. 1b, so as to flatten its visible surface and so as to equalize its thickness. Indeed, as FIG. 1a represents in an exaggerated manner, the support layer 12 is likely to have a variation in thickness. In particular, the surface of the base layer 12 may have a succession of hollows and bumps due to a surface tension phenomenon appearing during the baking of the base layer 12, and the thickness of the base layer 12 may be greater in the center of the covering surface 110 than on its periphery because of the wettability of said layer. Furthermore, if the covering surface 110 does not extend horizontally, that is to say it forms a slope, the base layer 12 may have a tendency to flow, during its cooking, in the direction of the slope, and therefore to generate an excess thickness, under the effect of gravity and due to its viscosity when hot.

[0024] The surfacing of the support layer 12 is preferably carried out by mechanical abrasion, for example by grinding or by sanding.

[0025] Next, a decorative element 13 is deposited on all or part of the support layer 12, as shown in FIG. 1c. Such a decorative element 13 is deposited in solid form. The decorative element 13 is advantageously made of ceramic material and/or metallic material, the material of said decorative element 13 being chosen so that it has a melting temperature higher than the glass transition temperature of the material constituting the support layer 12, for example higher than 600 degrees Celsius. In the present text, the terms “metallic material” designate any metal alloy, any pure metal or any metal composite.

[0026] The decorative element 13 is then sealed on the substrate 11 by baking the assembly consisting of the substrate 11, the support layer 12 and the decorative element 13, so as to form a covering part 10. The baking can be carried out at a temperature between 500 degrees Celsius and 1500 degrees Celsius. The temperature of this baking corresponds to a glass transition temperature of the material of the support layer 12, and must be lower than the melting point of the material constituting the decorative element 13 so as not to cause its deterioration.

[0027] Pressure may be applied to the decorative element 13 during baking to ensure its adhesion to the support layer 12. Such pressure may be exerted by a weight placed on the decorative element 13.

[0028] The baking of the substrate 11 and the support layer 12 can advantageously be carried out during the step of sealing the decorative element 13 on the substrate 11 when the melting temperature of the material constituting the decorative element 13 is greater than 1000 degrees Celsius. Thus, a single baking step allows the melting of the support layer 12 and the sealing of the decorative element with the substrate 11. In this case, it is obvious that the method does not include a step of surfacing the support layer 12.

[0029] The second variant of implementation of the invention corresponds to the first variant described above with the exception of carrying out a preliminary step, before depositing the support layer 12, in which a blind cavity 14 forming the decorative zone is produced in the substrate 11. In particular, the cavity 14 is produced through the covering surface 110. This cavity 14 is therefore intended to receive the support layer 12 and the decorative element 13 during their respective deposition. It is produced so that its shape corresponds to the shape of the decorative element 13, as visible in FIG. 1f. This cavity 14 can be produced by laser machining.

[0030] Furthermore, the decorative element 13 is deposited so as to extend beyond the cavity 14.

[0031] The cavity 14 has a depth of at least 0.01 mm, preferably 0.1 mm, so as to facilitate the positioning of the decorative element 13 within the cavity 14.

[0032] In this variant implementation of the invention, the support layer 12 can be deposited in powder form in the cavity 14.

[0033] More generally, it should be noted that the implementation and embodiment modes considered above have been described as non-limiting examples, and that other variants are consequently conceivable.

Claims (8)

1. A method for three-dimensional decoration of a substrate (11) in order to produce a cladding part (10) comprising the steps of: – depositing at least one enamel support layer (12) on a decorative area of a cladding surface (110) of a substrate (11) made of ceramic, said decorative area being intended to receive a decorative element (13); – firing the substrate (11) comprising the support layer (12) so as to cause the latter to melt; – depositing a decorative element (13) made of ceramic material and/or metallic material in solid form on the support layer (12), the material of which is chosen such that its melting temperature is higher than the glass transition temperature of the material constituting the support layer (12); – sealing the decorative element (13) on the substrate (11) by firing so as to form a cladding part (10). 2. Method according to claim 1, in which the baking of the substrate (11) and the support layer (12) and the sealing of the decorative element (13) on the substrate (11) are carried out during the same step, when the melting temperature of the material constituting the decorative element (13) is greater than 1000 degrees Celsius. 3. Method according to claim 1 or 2, in which a blind cavity (14) is made in the substrate (11) so as to form the decorative zone and so that its shape corresponds to the shape of the decorative element (13), the latter being deposited so as to extend beyond said cavity (14). 4. Method according to claim 3, in which the cavity (14) has a depth of at least 0.01 mm, preferably 0.1 mm. 5. Method according to one of claims 1 to 3, in which the support layer (12) is made of borosilicate enamel or feldspar. 6. Method according to claim 5, in which the support layer (12) is made of sodium borosilicate enamel. 7. Method according to claim 1, wherein when the melting temperature of the material constituting the decorative element (13) is less than 1000 degrees Celsius, following the step of baking the substrate (11) comprising the support layer (12), the latter is surfaced so as to flatten its surface and so as to equalize its thickness. 8. Method according to one of claims 1 to 6, wherein during the sealing step the temperature to which the substrate (11), the support layer (12) and the decorative element (13) are subjected is between 500 degrees Celsius and 1500 degrees Celsius.