EP3587626A1 - Decorative part made by incrustation - Google Patents

Abstract

The invention relates to a method of manufacturing a part (1) comprising a support (2) provided with at least one recess (4) filled with an aesthetic element (3) forming a decoration on one face (2a) of the part (1) intended to be visible, said method comprising the steps of: - Providing the support (2) provided with said at least one recess (4) and providing a preform intended to form the aesthetic element ( 3) of the part (1), - Inlay by hot pressing of the preform in said at least recess (4) of the support (2), the method being characterized in that the preform is made of a crystalline aluminum alloy , the inlaying step being carried out at a temperature between the solidus temperature and the liquidus temperature of the crystalline aluminum alloy. The invention also relates to the part (1) resulting from the process.

Description

TECHNICAL AREA

The present invention relates to a method of manufacturing a decorative piece comprising a step of inlaying by hot pressing of a crystalline metallic alloy in a support in particular ceramic and to the decorative piece resulting from the process.

PRIOR ART

It is known to decorate watch components in watchmaking with aesthetic elements. There are, for example, watch glasses decorated with patterns such as indices. These glasses, generally made of ceramic, can be marked in different ways and with different materials such as gold, silver or platinum. Said marking can be carried out in relief or in depth. In the case of deep marking, this is achieved by filling recesses previously machined in the support. The principle used for carrying out this marking consists in depositing a conductive bonding layer by physical vapor deposition (PVD). Once the bonding layer has been deposited, the recesses are filled with metal by electroforming. This process has the disadvantages of being complex and extremely slow.

Another process described in the document EP 2,315,673 consists in pressing in the aesthetic elements in the recesses made in the support. This document describes more particularly a method of inlaying by hot pressing of an aesthetic element produced in amorphous metallic material within a ceramic support to form, for example, indices on a watch bezel. The use of an amorphous metal for the incrustation makes it possible to work under low stresses and temperatures without risk of weakening the material of the support. However, the lack of contrast between the amorphous metal and the ceramic support does not allow an optimal visual rendering. Furthermore, the method of manufacturing a decorative piece by inlaying an amorphous metal is relatively expensive because it requires adequate treatment to maintain the amorphous structure of the metal.

SUMMARY OF THE INVENTION

To overcome the aforementioned disadvantages, the present invention aims to provide a method of manufacturing a decorative piece comprising a step of inlaying by pressing a crystalline metal alloy in one or more recesses formed in a support which is in particular in ceramic. The inlay of a crystalline metal aims to increase the contrast between the aesthetic element and its support and to reduce manufacturing costs. According to the invention, the choice of crystalline metal relates to an aluminum alloy which has the particular advantage of being deformable at low temperature compared to other crystalline metal alloys. The method according to the invention thus makes it possible to produce a decorative piece comprising one or more aesthetic elements in aluminum, which is difficult to achieve with other methods, whether by PVD deposition or by electroforming.

Advantageously, the manufacturing process comprises, following the incrustation step and a possible mechanical rectification step, an electrochemical treatment aimed at modifying the surface condition of the esthetic elements encrusted for the purposes of protection and / or aesthetic purposes. This treatment can consist of a selective anodization of said elements with or without coloring. Since the support, in particular ceramic, is not an electrical conductor, one or more of the recesses open onto one face of the decorative piece intended to be not visible in use. These recesses communicating with the non-visible face form as many contact points making it possible to bring the current to the aesthetic elements to be treated electrochemically. Thanks to these non-visible contact points, it is possible to bring current to fine and numerous decors such as on a tachymeter scale of a watch bezel. A wide range of colors and even gradations of colors can be obtained on these decorations. It is also possible to encrust an aluminum alloy at a lower cost and then make it hard by anodization. This electrochemical treatment is carried out on the decorations encrusted in their final surface condition: polished, satin, sanded and therefore at the end of the manufacturing process.

Other characteristics and advantages of the present invention will appear in the following description of preferred embodiments, presented by way of nonlimiting example with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

• The figure 1 represents a plan view of a decorative piece and, in particular, of a watch bezel comprising indices in aluminum alloy produced by inlaying with the method according to the invention.
• The figure 2 represents a partial sectional view of this same decorative piece.
• The figures 3 to 7 schematically represent the steps of embedding the aluminum alloy preform in the support with the method according to the invention.
• The Figures 8 and 9 respectively represent two variants of the means used according to the invention to maintain the aesthetic element within the recess.
• The figure 10 represents a variant of the figure 2 with the recesses opening onto the rear face, that is to say the non-visible face, of the telescope.
• The figure 11A represents a view of the front face, that is to say of the visible face, of the bezel inlaid with several aesthetic elements, as well as a view in partial section of the bezel, focused on an aesthetic element. The figure 11B represents a view of the rear face of this same telescope.
• The figure 12A represents a three-dimensional view of a watch case comprising on the middle a recess communicating with the bar hole. The figure 12B represents this same watch case including an aesthetic element embedded in the recess. The figure 12C represents this same watch case comprising the aesthetic element embedded in the recess and set with stones.

DETAILED DESCRIPTION

The present invention relates to a process for manufacturing a decorative piece by hot pressing, also called inlaying, of one or more aesthetic elements in a support provided with one or more recesses and to the decorative piece resulting from the process . The piece may in particular be a component for covering watchmaking such as a bezel, a dial, a case, a crown, a push-piece, a crystal, a bracelet element, etc. As an example illustrated in Figures 1 and 2 , the part 1 is a watch bezel comprising an annular body forming the support 2 provided with recesses 4 formed in said support 2 to receive the aesthetic elements 3 forming the indices.

According to the invention, the aesthetic element is made of a crystalline metal alloy and more precisely of a crystalline aluminum alloy. The support, for its part, is preferably made of a material which is not very ductile. It can, for example, be a ceramic, sapphire, enamel, etc. Preferably, it is a ceramic and, more preferably, a zirconia. Thus, the part may consist of a zirconia watch bezel with indices made from an aluminum alloy. In particular, it may be alloy 7075 which comprises zinc up to ∼ 6% by weight. The advantage of aluminum alloy is that it is malleable at low temperatures due to its low melting temperature of around 650 ° C.

The support 2 comprises at least one recess 4 produced by laser engraving, by machining, etc. The recess 4 has on the surface 2a of the support 2 intended to be visible a shape 4a corresponding to the outline of the desired decoration. This recess 4 can be blind ( figure 2 ) or lead to an invisible side 2b of the support 2 ( figure 10 ). Advantageously, the entire volume of the recess 4 is filled with the aesthetic element 3 projecting or flush with the surface 2a of the support 2. As a variant, it is also possible that the aesthetic element only partially fills the volume of the recess. The recess 4 has flanks 7 with a geometry suitable for optimal maintenance of the aesthetic element within the recess. As shown in diagram figure 3 , the sides 7 may be substantially perpendicular to the visible surface 2a of the support 2 with the aesthetic element maintained by friction within the recess. According to a preferred variant not shown, the sides are at least partially inclined with a narrowing in the direction of the visible surface preventing the displacement of the aesthetic element outside the recess. According to another preferred variant shown in figure 8 , the sides 7, whether inclined or not, are pierced with housings 5 which, after filling with the aesthetic element, form a stop which, like the inclined walls, prevents the aesthetic element from moving. According to another preferred variant shown in figure 9 , protuberances 6 can be arranged in the recess 4 to ensure a similar role of means for holding the aesthetic element.

According to the invention, the aesthetic elements are encrusted by hot pressing in the recesses of the support at a temperature between the solidus temperature and the liquidus temperature of the aluminum alloy constituting the aesthetic element typically between 500 ° C. and 650 ° C. More specifically, the incrustation steps of the manufacturing process according to the invention are illustrated schematically using the figures 3 to 7 . First of all, the support 2 provided with the recess (s) 4 is made available ( fig.3 ). Similarly, the preform (s) intended to form the aesthetic element (s) 3 are made available. In the case of a watch bezel to be decorated with aluminum indices, the aesthetic element to be inlaid is in the form of an annular preform with a diameter and a ring width of dimensions substantially equivalent to those of the indices. To prevent the preform from sticking to the press during encrustation, a non-stick layer, e.g. made of boron nitride, can be applied to the surface intended to be in contact with the press. In a first step, the support is preheated to avoid thermal shock. Preferably, the preheating temperature is between 300 and 500 ° C. Then, the preform 3 is placed on the surface 2a of the support 2 at the level of the recess 4 ( fig.4 ). The assembly is placed in a press where the preform is heated to a temperature between the solidus and the liquidus of the material constituting the preform, which makes it possible to soften the material before pressing. Then, a pressure P is applied to the preform 3 to fill the recesses 4 with the aluminum alloy ( fig. 5 and fig. 6 ). Preferably, the load during encrustation is kept at a value of less than 1000 kg to avoid damaging the support. This load is advantageously between 500 and 800 kg. This pressing cycle can be carried out in several stages with a precharge stage before increasing the pressure to the desired maximum pressure. The step of encrusting the aluminum alloy in the recesses is then followed by a cooling step and a possible mechanical rectification step such as a polishing allowing to remove the surplus of the aesthetic element. 3 ( fig.7 ) and make visible surfaces of the support and of the aesthetic element connected to each other without any continuity solution.

For example, in the case of an inlay of the aluminum metal alloy 7075 in a support based on zirconia. The support was preheated to 450 ° C, the preform was heated to 550 ° C for 90 seconds and pressed under a load of the order of 750 kg.

Advantageously, after the mechanical rectification step, the aesthetic element is subjected to a finishing treatment. This treatment can consist of a selective electrochemical treatment of the encrusted metallic material, and more precisely, an anodization with or without coloring to modify the appearance and / or the hardness of the encrusted material. The supports targeted by the present invention being predominantly electrically non-conductive, the difficulty lies in the routing of the current to the aesthetic elements during the electrochemical treatment and this, via contact points which must imperatively not be visible on the decorative piece. . To this end, one or more of the recesses are configured to lead to a face intended to be invisible from the decorative piece. These recesses opening onto the non-visible face form as many contact points making it possible to bring the current to the embedded aesthetic elements. Returning to the example of the ceramic watch bezel comprising indices produced by inlaying a crystalline aluminum alloy, the recess 4 for each of the indices opens onto the rear face 2b of the bezel 1 as illustrated in figure 10 . The contact points 4b make it possible to bring the current to each of the indices during the electrochemical treatment. These contact points 4b on the rear face 2b of the support 2 may have a cross section which is less than that of the part 4a of the recess opening onto the visible face 2a of the support 2. These contact points allow the same electrochemical treatment to be carried out. for each index or possibly to combine different treatments and therefore colors by bringing the current to only one or more of the indices for each electrochemical treatment.

If the aesthetic element 3 is larger, as in the examples of figures 11A and 12B , several points of contact per aesthetic element may be required to ensure uniform electrochemical treatment of the aesthetic element. To the figure 11A , for example, three aesthetic elements 3 are distributed over an annular portion of the visible face 2a of the telescope 1. In this configuration, the aesthetic elements 3 are embedded on the substrate 2 including the indicia made of a non-conductive material . On its rear side 2b visible at the figure 11B , the telescope 1 is provided with several orifices 4b communicating with the recesses 4 to produce the contact points making it possible to bring the current to these three elements. As shown in the figure 11A in the sectional view, two contact points 4b are provided per aesthetic element 3. The Figures 12B and 12C represent another configuration of an aesthetic aluminum element embedded in a recess formed in a support. The aesthetic element 3 extends up to a horn 8a of the middle part of the watch case 8 and includes housings 3a for the setting of stones 9. In a similar manner to the other examples, the recess receiving the aesthetic element opens out at least in one place on an invisible side of the watch case. It is thus conceivable that the recess 4 communicates with the bar hole 10 as illustrated in the figure 12A . Of course, the recess 4 can communicate in several places through other through orifices making it possible to produce contact points bringing the current to the aesthetic element 3 The present invention thus makes it possible, thanks to the electrical contact point (s) provided (s) on an invisible side of the watch case, electrochemically treating the aesthetic element after crimping with the stones.

The present invention has been more specifically illustrated for a decorative timepiece, but it goes without saying that the process according to the invention applies to the production of decorative pieces in many other fields such as jewelry, telephony, cars, etc.

Legend of figures

1. (1) Decorative piece
2. (2) Support
   1. at. Visible face
   2. b. Invisible face
3. (3) Aesthetic element or preform
   1. at. Housing
4. (4) Digging
   1. at. Part leading to the visible face of the support
   2. b. Part leading to the non-visible side of the support, also called contact point
5. (5) Housing in the recess
6. (6) Outgrowth in the recess
7. (7) Side of the hollow
8. (8) Watch case
   1. at. Horn
9. (9) Stone
10. (10) Bar hole

Claims (20)

Method of manufacturing a part (1) comprising a support (2) provided with at least one recess (4) filled with an aesthetic element (3) forming a decoration on one face (2a) of the part (1) intended to be visible, said method comprising the steps of: - Provision of the support (2) provided with said at least one recess (4) and provision of a preform intended to form the aesthetic element (3) of the part (1), - Inlay by hot pressing of the preform in said at least one recess (4) of the support (2), the method being characterized in that the preform is produced in a crystalline aluminum alloy, the inlaying step being carried out at a temperature between the solidus temperature and the liquidus temperature of the crystalline aluminum alloy. Method according to claim 1, characterized in that the support (2) is made of a material chosen from ceramic, sapphire and enamel. Method according to claim 1 or 2, characterized in that the support (2) is made of a ceramic based on zirconia. Process according to any one of the preceding claims, characterized in that the crystalline aluminum alloy is alloy 7075. Method according to any one of the preceding claims, characterized in that the support (2) is preheated before the incrustation step at a temperature between 300 and 500 ° C. Method according to any one of the preceding claims, characterized in that the incrustation step by hot pressing is carried out under a load of between 500 and 1000 kg. Method according to any one of the preceding claims, characterized in that the incrustation step by hot pressing is carried out at a temperature between 500 and 650 ° C. Method according to any one of the preceding claims, characterized in that it comprises, after the incrustation step, a step of surface treatment by electrochemical means of the aesthetic element (3). Method according to Claim 8, characterized in that the said electrochemical surface treatment step is carried out after a mechanical rectification step following the incrustation step. Method according to claim 8 or 9, characterized in that said at least one recess (4) opens at one or more places on one face (2b) of the part (1) intended to be invisible, to respectively form one or more points of contact (4b) for bringing current during the surface treatment on the aesthetic element (3). Piece (1) comprising a support (2) provided with at least one recess (4) filled with an aesthetic element (3) forming a decoration on a face (2a) visible from the part (1), said aesthetic element (3 ) being made of a crystalline aluminum alloy. Piece (1) according to claim 11, characterized in that the support (2) is made of a material chosen from ceramic, sapphire and enamel. Piece (1) according to claim 11 or 12, characterized in that the support (2) is made of a ceramic based on zirconia. Piece (1) according to any one of claims 11 to 13, characterized in that the crystalline aluminum alloy is the alloy 7075. Piece (1) according to any one of claims 11 to 14, characterized in that said at least one recess (4) opens into or several places on one face (2b) of the part (1) intended to be invisible. Piece (1) according to any one of claims 11 to 15, characterized in that it is a covering component in watchmaking or in jewelry. Piece (1) according to claim 16, characterized in that it is a watch bezel forming the support (2) with at least one recess (4) filled with the crystalline aluminum alloy forming as an element aesthetic (3) an index or an annular portion of the telescope. Piece (1) according to claim 16, characterized in that it is a middle part forming the support (2) with at least one recess (4) filled with the crystalline aluminum alloy forming as an aesthetic element ( 3) a portion of the middle extending to a horn (8a) of the middle. Piece (1) according to claim 18, characterized in that said at least one recess (4) communicates with a bar hole (10) disposed in the horn (8a). Piece (1) according to any one of claims 11 to 19, characterized in that the aesthetic element (3) comprises an anodized layer.

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