EP3623877B1 - Method for manufacturing a clock component - Google Patents

Description

Introduction

The present invention relates to a method for manufacturing a watch component. The invention also relates to a watch component as such. Finally, the invention also relates to a timepiece comprising such a watch component.

State of the Art

It is known to produce watch components from various materials, including in particular metals, metal alloys and technical ceramics. The visible surface of such a component can have several different aspects, depending on the different finishing stage(s) chosen. The surface condition of this visible surface thus makes it possible to achieve a particular, desired aesthetic appearance. Such a visible surface can have reliefs relative to a main surface, made set back from this main surface, for example in the form of hollows, or conversely forming a relief protruding from this main surface.

• ils comprennent des étapes complexes pour former les états de surface du composant horloger fini ;
• dans le cas de composants horlogers présentant des reliefs, notamment des reliefs en retrait, les procédés existants sont peu adaptés ou sont complexes pour former certains états de surface différents sur les différentes surfaces des différents reliefs, par exemple en nécessitant des étapes de masquage de certaines parties ;
• dans le cas de composants horlogers comprenant des surfaces en retrait, les procédés existants ne permettent pas d'obtenir certains résultats particuliers d'états de surface sur les différentes surfaces des différents reliefs.

Existing processes for manufacturing a watch component, particularly in ceramic, have all or part of the following disadvantages:

• they include complex steps to form the surface conditions of the finished watch component;
• in the case of watch components with reliefs, in particular recessed reliefs, existing processes are poorly suited or are complex for forming certain different surface conditions on the different surfaces of the different reliefs, for example by requiring steps to mask certain parts;
• in the case of watch components comprising recessed surfaces, existing processes do not allow certain particular surface condition results to be obtained on the different surfaces of the different reliefs.

The general objective of the invention is to provide an improved and simplified solution for forming a watch component with an attractive aesthetic appearance, comprising recessed reliefs, and which does not include all or part of the drawbacks of the state of the art.

More specifically, an object of the invention is to provide a solution for forming a watch component comprising a first surface having a surface condition different from that of a second surface, located set back from said first surface.

Potentially relevant state of the art:
EP2138323A1
“Remove Scratches and Polish Your Stainless Steel G-Shock”, https://www.youtube.com/watch?v=6-jR4pgeqMA

Brief description of the invention

To this end, the invention is based on a method of manufacturing a watch component for a timepiece, according to claim 1.

The at least one recess comprises a recess surface, or second surface, set back from the first surface, not covered at the time of implementation of the second termination step, this recessed hollow surface retaining an unchanged surface condition at the end of the second termination stage compared to its surface condition at the start of the second termination stage.

The method of the invention makes it possible to produce a watch component comprising a first surface, in which at least one hollow is arranged, characterized in that all or part of the first surface has a first surface condition obtained by tribofinishing and/or chemical-mechanical polishing and/or by tumbling and/or by trovalization and/or by sandblasting and/or by micro-blasting and/or by wet spraying, different from the second surface condition, in particular the roughness, in particular measured by the parameters Ra and/or Str, and/or the shine, of at least a portion of the at least one hollow.

Finally, the invention is also based on a timepiece, in particular a watch, characterized in that it comprises a timepiece component as described previously.

The invention is more precisely defined by the claims.

Brief description of the figures

• Les figures 1a à 1c représentent schématiquement une vue en coupe dans l'épaisseur d'un composant horloger selon un mode de réalisation de l'invention.
• La figure 2 représente schématiquement une vue en coupe dans l'épaisseur d'un composant horloger selon une première variante du mode de réalisation de l'invention.
• La figure 3 représente schématiquement une vue en coupe dans l'épaisseur d'un composant horloger selon une deuxième variante du mode de réalisation de l'invention.
• La figure 4 est une photographie d'un composant horloger fabriqué selon un mode de réalisation de l'invention.
• La figure 5 représente un profil linéaire brut de rugosité du composant horloger de la figure 4.
• La figure 6 est une photographie d'un autre composant horloger fabriqué selon un mode de réalisation de l'invention.
• La figure 7 représente un profil linéaire brut de rugosité du composant horloger de la figure 6.

These objects, characteristics and advantages of the invention will be explained in detail in the following description of particular embodiments made without limitation in relation to the attached figures among which:

• The f Figures 1a to 1c schematically represent a sectional view through the thickness of a watch component according to one embodiment of the invention.
• There figure 2 schematically represents a sectional view through the thickness of a watch component according to a first variant of the embodiment of the invention.
• There figure 3 schematically represents a sectional view through the thickness of a watch component according to a second variant of the embodiment of the invention.
• There figure 4 is a photograph of a watch component manufactured according to one embodiment of the invention.
• There Figure 5 represents a rough linear roughness profile of the watch component of the figure 4 .
• There figure 6 is a photograph of another watch component manufactured according to an embodiment of the invention.
• There figure 7 represents a rough linear roughness profile of the watch component of the figure 6 .

Description of the invention

To simplify the description, we will use the same references to designate the same characteristics or equivalent characteristics in the different embodiments.

The invention relates to the production of a watch component 10 of any chemical composition and in particular of metal and/or metal alloy and/or technical ceramic. Such a component can thus for example be obtained from stainless steel, precious metals, titanium, alumina, doped or undoped strontium aluminate, stabilized or unstabilized zirconia, hybrid material organic-inorganic or generally in any metal alloy or in any technical ceramic or in any composite usable in the field of watchmaking. By "technical ceramic", we mean dense materials based on aluminum oxide, and/or zirconium oxide, and/or stabilized zirconium oxide, and/or nitrides, and/or carbides, and/or strontium aluminate, in particular doped. By "dense", we consider a material whose density is between 95% and 100% of the theoretical density of the material considered. The expression "based on a certain compound" will mean that the material will comprise by weight at least 50% of said compound. To simplify the description, we will use the term "ceramic" to designate "technical ceramic".

The watch component 10 may be a single piece or comprise a combination of different parts assembled together. Thus, it may be of a single chemical nature or a combination of chemical natures. It may therefore comprise the same material or several different materials. It may be in a single color or be of several colors.

The invention further relates to any type of watch component. This watch component 10 may be a bezel, a bezel disc, but more generally any exterior element, a case, a back, a caseband, a dial, a decorative plate, or a bracelet link. This component may also be a component of the movement, such as a date disc for example.

The invention is more particularly concerned with a watch component 10 having at least one recessed relief defined by a recessed surface relative to the main surface 5 of the watch component, a recessed relief generally called a hollow. The main surface 5 is considered here as being the largest visible surface of the watch component.

A second recessed surface 20 or hollow 20 is more precisely formed in a first surface 1 of the watch component, which constitutes all or part of the main surface 5. This recessed surface 20 is hollowed out in the first surface 1; an edge 4 forms an interface between the first surface 1 and the recessed surface 20. The latter may be flat or curved. It may, for example, be frustoconical. It may also be continuous or discontinuous, that is to say, it may be formed of several flat or curved surfaces connected by edges. The hollow 20 may thus take any shape. It may in particular comprise at least a third surface 2 forming a bottom, which may be connected to the first surface 1 by a connecting surface 3. The third surface 2 and/or the connecting surface 3 may be continuous or discontinuous.

For example, the second recessed surface 20 or hollow 20 may comprise a third surface 2 forming a bottom substantially parallel to the first surface 1, connected to the first surface by one or more side walls acting as a connecting surface 3 substantially perpendicular to the bottom, forming a flat-bottomed crenellated shape, as illustrated by the hollow 20 of the Figure 1a Such a background may, for example, include a symbol or an alphanumeric character intended to display a time indication or a time-derived indication or any marking.

Alternatively, the second recessed surface 20 or hollow 20 may be in the form of a curved surface comprising a rounded section forming a U, as illustrated by the hollow 20 of the Figure 1b . In this particular variant, it is not possible to distinguish the bottom from the connecting surface. In this case, it will be considered that the third surface 2 integrates the connecting surface 3.

Alternatively, the second recessed surface 20 or hollow 20 may be in the form of a discontinuous surface comprising a V-shaped section, as illustrated by the hollow 20 of the Figure 1c .

Alternatively (not shown in the figures), the second recessed surface 20 or hollow 20 may not have a bottom. In this case, the hollow 20 is a through surface, i.e. it passes through the watch component 10 on either side.

The invention relates to the method for manufacturing such a watch component. This method comprises a first step consisting of preparing a watch component 10 comprising a main surface 5 and a first surface 1 in which at least one hollow 20 is arranged.

This element resulting from the first stage substantially presents the final shapes and dimensions of the watch component; it will already be called a watch component, even if it is not completely finished. As a note, this first stage is implemented in a known manner, by any process of the state of the art.

For aesthetic reasons, a portion of the main surface 5 may be spared from the treatment according to the invention so as to retain its initial surface condition. In the invention, the first surface 1 is considered to be a surface in which at least one hollow is arranged and which is concerned by the remainder of the method, i.e. its surface condition will be modified. This surface condition will in particular be characterized, in a non-limiting manner, by the roughness, particularly by means of the standardized roughness parameters Ra and/or Str, and/or by the gloss, or even by the color, as will be detailed later on the basis of several examples.

For example, the first step might be to make a ceramic bezel disc or a decorative metal plate with recesses.

The concept of the invention consists in implementing a second finishing/termination step, which makes it possible to finalize the surface states of the watch component, in particular which makes it possible to easily obtain different surface states between the first and second surfaces of the watch component. For this, the second step of the invention more precisely implements a step of terminating the watch component 10 inducing a modification of the surface state of the first surface, for example aimed at reducing the specular reflection, without affecting or affecting as little as possible the at least one hollow (i.e. the at least one recessed surface), nor noticing a possible spared part of the main surface.

The recessed surface 20 may optionally be affected by the second termination step at the edge 4 forming an interface between the first surface 1 and said recessed surface 20. Considering a plane P1 passing through two points p1, p2 of an edge 4 forming two ends of a section of a hollow 20, and perpendicular to the cutting plane P of said section, the second termination step may for example affect a portion of said hollow 20 or second recessed surface 20 which is comprised between the plane P1 and a plane P2 parallel to the plane P1 and distant by a distance d from the plane P1 in the direction of the interior of said hollow, as shown in the Figures 1a to 1c . In other words, the surface condition of the hollow can possibly be modified over a distance d strictly less than the depth of the hollow. The depth is measured in a direction perpendicular to the planes P1 and P2.

Preferably, the distance d does not exceed 80 µm, or even 50 µm, or even 20 µm. Naturally, this distance can be zero.

A third surface 2 forming a background, like that represented by the Figure 1a , is not affected by the second termination step. The bonding surface 3, as represented by the figures 1a or 1c , or the third surface 2 forming both a bottom and a connecting surface, as in the case represented by the Figure 1b , can however be at least partially modified by the second termination step over a depth d.

Finally, in all cases, at least a portion of the second recessed surface will retain an unchanged surface condition during this second termination stage which will be detailed later.

By finishing step we mean a modification of the surface condition of the first surface 1 by interposed media. The particularity of this finishing process is to make it possible to obtain such a result without masking protecting the hollows, with so-called "free" media and abrasives; the contact between the abrasives and the surface to be finished is made by impacts and not by friction as in the case of polishing. This step includes, for example, the mechanical stressing of an abrasive mixture by impacts, for example by vibratory, oscillatory or rotary movement, for example in a tank (tribofinishing). It also includes, for example, in a non-limiting manner, tumbling, and/or trovalization, and/or sandblasting and/or micro-blasting and/or wet spraying of said first surface 1.

The finishing step uses an abrasive that may be supported by media. In the case of vibratory finishing, the dimension and/or geometry of the media is defined so as to prevent any contact of the media with at least a deepest portion of the recess, namely a portion arranged below a plane P2 as defined above, in particular to prevent any contact with a third surface 2 forming a bottom. The media may have a polyhedral, in particular pyramidal, or spherical shape. They may be made of glass, ceramic, porcelain, steatite, alumina, or zircon (ZrSiO ₄ ). In the case of sandblasting and/or micro-blasting and/or wet spraying, these are the abrasive particles whose size and/or geometry are/is defined so as to prevent any contact with at least a portion of the hollow, in particular with a third surface 2 forming a bottom.

• des médias (aussi appelés porteurs ou chips) disposés par exemple dans une cuve dont le rôle est de transférer le mouvement de la cuve au mélange abrasif et aux composants horlogers à traiter, de façon à générer des sollicitations mécaniques qui permettent d'atteindre l'effet abrasif sur le composant horloger. La nature chimique, la géométrie et les dimensions initiales des médias sont choisies pour obtenir le résultat souhaité. Le média peut être abrasif. De même, le vieillissement et l'usure des médias sont surveillés, pour les conserver dans des limites à tolérer ;
• un abrasif, sous forme de poudre ou de pâte, dont le rôle est d'amplifier l'effet des frottements et des sollicitations mécaniques, et donc l'effet abrasif. Les particules abrasives utilisées dans le sablage et/ou le microbillage et/ou le giclage humide sont considérées comme un média abrasif ;
• un liquide (par exemple de l'eau, ou une huile, avec un additif ou non, ou un mélange de liquides) qui fluidifie le mélange et limite l'augmentation de la température lors de l'opération de terminaison. Il peut être optionnel, par exemple dans le cas d'un sablage.

The composition of the abrasive mixture may include at least the first of the following three components:

• media (also called carriers or chips) arranged for example in a tank whose role is to transfer the movement of the tank to the abrasive mixture and to the watch components to be treated, so as to generate mechanical stresses which make it possible to achieve the abrasive effect on the watch component. The chemical nature, geometry and initial dimensions of the media are chosen to obtain the desired result. The media can be abrasive. Similarly, the aging and wear of the media are monitored, to keep them within the limits to be tolerated;
• an abrasive, in powder or paste form, whose role is to amplify the effect of friction and mechanical stress, and therefore the abrasive effect. The abrasive particles used in sandblasting and/or micro-blasting and/or wet spraying are considered an abrasive media;
• a liquid (e.g. water, or oil, with or without an additive, or a mixture of liquids) which fluidifies the mixture and limits the increase in temperature during the finishing operation. It may be optional, for example in the case of sandblasting.

• une conformation, notamment la dimension et la géométrie, qui ne leur permet pas de venir en contact avec au moins une portion d'une creusure ou d'une surface en retrait, et de préférence avec l'intégralité de la troisième surface 2 formant un fond. Par exemple, les médias sont de géométrie et de dimension adaptées de façon à être susceptibles de venir en appui sur les arêtes 4 à l'interface entre la première surface 1 et une creusure, en sommet d'au moins une creusure, pour ne pas toucher notamment la troisième surface 2 de ladite creusure ;
• une masse et une composition chimique permettant la tribofinition sans égrisure des arêtes de la creusure ;
• une composition de matière soumise à des paramètres permettant aux médias de s'user uniformément au cours de la tribofinition (et notamment de ne pas se fracturer). Pour cela, comme mentionné précédemment, les médias peuvent par exemple être notamment en verre, en céramique, en porcelaine, en stéatite, alumine ou en zircon (ZrSiO₄).

The composition of the abrasive mixture includes media with the following characteristics:

• a conformation, in particular the dimension and geometry, which does not allow them to come into contact with at least a portion of a hollow or a recessed surface, and preferably with the entirety of the third surface 2 forming a bottom. For example, the media are of geometry and dimension adapted so as to be capable of coming into contact with the edges 4 at the interface between the first surface 1 and a hollow, at the top of at least one hollow, so as not to touch in particular the third surface 2 of said hollow;
• a mass and a chemical composition allowing tribofinishing without chipping of the edges of the hollow;
• a material composition subject to parameters allowing the media to wear uniformly during tribofinishing (and in particular not to fracture). For this, as mentioned previously, the media can for example be made of glass, ceramic, porcelain, steatite, alumina or zircon (ZrSiO ₄ ).

The method for manufacturing a timepiece component 10 for a timepiece may comprise an intermediate step between the two aforementioned steps, consisting of modifying the surface condition of all or part of the main surface 5 and possibly of the second recessed surface 20 aimed at maximizing specular reflection. This modification may form surfaces of homogeneous and isotropic topography. For example, this step may correspond to polishing the surfaces aimed at making them shiny. The second finishing step modifies the surface condition of the first surface 1 so as to give it a homogeneous and isotropic topography with reduced specular reflection. In this case, this finishing step is a step of mattifying the previously polished first surface 1. Such an approach thus makes it possible to obtain a timepiece component 10 comprising a first matte surface 1, and a second recessed surface 20 whose surface condition surface is at least partially unchanged. Such an approach makes it possible in particular to obtain a watch component 10 which may comprise a first matte surface 1, and a third surface 2 forming a background whose surface condition is unchanged.

Thus, the second termination step modifies the surface condition of all or part of the main surface 5 to give the first surface 1 a homogeneous and isotropic topography, while reducing or even minimizing its specular reflection.

The first step of manufacturing a watch component 10 may be followed by an intermediate step, such as a step of depositing a coating in the at least one recess or recessed surface, in particular of the third surface 2, single-layer or multi-layer, in particular by a step by PVD (acronym originating from the process known by the English name “Physical Vapor Deposition”), by CVD (acronym originating from the process known by the English name “Chemical Vapor Deposition”), by ALD (acronym originating from the process known by the English name “Atomic Layer Deposition”), by LBL (acronym originating from the process known by the English name “Layer by Layer”), by ink-jet, by dip-coating, by brush, by dispenser, by spraying, by nebulization or by sol-gel process. For this, the deposit is for example first carried out on the entire part, then is removed from the first surface 1 for example during the intermediate step as described above. Such a coating may comprise a layer composed of metal(s) and/or oxide(s) and/or nitride(s) and/or carbide(s) and/or nitrocarbon(s) and/or sulfide(s) and/or organic material(s), and/or inorganic material(s), and/or hybrid material(s), and/or paint, and/or lacquer, and/or enamel, and/or varnish and/or glass-ceramic, and/or polymer-based or glue-based material.

There figure 4 is a photograph of a watch component 10 taken at the interface between the first surface 1 and the third surface 2 of a hollow, corresponding to an example comprising a hollow according to the Figure 1a , which will be detailed later.

The method may comprise an additional step after the second termination step, for example a diamond-coating step to make a portion of the main surface, in particular of the first surface 1, shiny, for example a part forming a bevel. Thus, the second termination step is not necessarily the last step of the manufacturing process.

In addition to the first example of watch component 10 comprising only one type of hollow, as illustrated in the Figures 1a to 1c , the watch component 10 may comprise at least one second type of hollow of any other geometry and/or a multitude of hollows, of the same geometry or not, nested within each other or not. Their conformations represent different embodiment variants.

There figure 2 illustrates by way of example, a watch component 10 according to an alternative embodiment. This watch component 10 comprises a first flat surface 1, in which a hollow relief is present. This hollow relief consists of a hollow 20 or a second recessed surface 20 comprising a connecting surface 3, which itself comprises second hollows 21 or fourth recessed surfaces 21 each comprising a fifth surface 22 forming a bottom. The first hollow 20 has a V shape, as in the example of the Figure 1c , and the second recesses 21 inserted in the connecting surface of the first recess 20 have a notched shape, as in the example of the Figure 1a . In this embodiment, the second termination step is chosen to only modify the surface condition of the first surface 1: thus, this step does not modify the surface condition of the recessed surfaces 20 and 21.

Alternatively, the surface condition of a portion of the second recessed surface 20, between planes P1 and P2 as defined previously, may also be affected by the second termination step, without the hollows or fourth recessed surfaces 21 being affected.

There figure 3 illustrates by way of example a watch component 10 according to another particular embodiment. This watch component 10 comprises a main surface 5, in which two hollows 20 and 20' are present, in different zones forming a first surface 1 possibly discontinuous between the two hollows. The second hollow 20' is wider than the first hollow 20 but less deep. In this embodiment variant, the hollow 20' is accessible to the media. Each hollow 20, 20' is configured as defined above with reference to the Figure 1c The termination step thus modifies the surface condition of the first surface 1 and the second hollow 20' without affecting the first hollow 20.

The invention will be illustrated on the basis of a few examples, in a non-limiting manner.

In a first embodiment, the watch component 10 made of ceramic, more precisely of yttria-containing zirconia, is a bezel disc. It has a main truncated surface 5, in particular a first truncated surface 1, in which recesses or recessed surfaces in the form of crenellations are made, comprising third surfaces each forming a bottom 2 as well as vertical or substantially vertical connecting surfaces 3 ensuring the connection between the first surface 1 and the third surfaces each forming a bottom. The recesses have a rectangular section, with a width of 0.69±0.05 mm and a depth of 0.15±0.05 mm. The bezel disc already has its final geometry, with the recesses.

• optionnellement un sablage et/ou un microbillage et/ou un giclage humide sur l'ensemble du disque ;
• le dépôt d'un revêtement métallique par PVD sur l'ensemble du disque ;
• un polissage qui supprime sélectivement le revêtement de la première surface 1, mais pas des creusures, et qui permet d'obtenir une topographie homogène et isotrope au niveau de la première surface 1, maximisant la réflexion spéculaire de cette première surface 1. Cette étape de polissage correspond à l'étape intermédiaire décrite plus haut.

After the first step of the manufacturing process, an intermediate step comprising the following sub-steps:

• optionally sandblasting and/or micro-blasting and/or wet spraying over the entire disc;
• the deposition of a metallic coating by PVD on the entire disc;
• a polishing which selectively removes the coating from the first surface 1, but not from the recesses, and which makes it possible to obtain a homogeneous and isotropic topography at the level of the first surface 1, maximizing the specular reflection of this first surface 1. This polishing step corresponds to the intermediate step described above.

• 750 g de médias (porteurs) (billes de verre de diamètre 5 mm) ;
• 20 g de lessive ;
• 20 g d'abrasif (poudre de carbure de bore de taille comprise entre 3 et 5 µm) ;
• 300 g d'eau.

Then, the manufacturing process includes a second step of finishing by tribofinishing, corresponding to a step of mattifying the first surface 1. For this, the equipment used is a centrifugal machine which includes satellites each comprising a one-litre bowl, in which the components to be tribofinishing are placed in bulk with:

• 750 g of media (carriers) (glass beads with a diameter of 5 mm);
• 20 g of detergent;
• 20 g of abrasive (boron carbide powder with a size between 3 and 5 µm);
• 300 g of water.

The rotation is set at 300 rpm for different durations.

In this first embodiment, the surface condition of the first surface 1 before the second tribofinishing step (roughness R1) is polished, and that of the third surface 2 forming the bottom of a hollow before the tribofinishing step (roughness R2) is sandblasted. After the tribofinishing step, the roughnesses respective values of the first surface 1 and the third surface 2 forming the bottom of a hollow become “R1'” and “R2'”. These roughness values according to this first embodiment example are summarized in the following table, which details the roughness values Ra and their deviations, in nanometers, as well as the Str, as well as the gloss measured with the gloss meter and expressed in gloss unit and the color expressed in the CIELab color space.

We note the characterization results of the first surface 1 before termination “1”, of the surface 1 after termination “1'”, of the third surface 2 before termination “2”, of the third surface 2 after termination “2'”. 1 1' 2 2' Roughness Ra in nm R1 = 2.0 ± 0.2 R1' = 200 ± 20 R2 = 370 ± 50 R2' = 370 ± 50 Roughness Str / Str _1' = 0.89± 0.03 Str ₂ = 0.64 Str _2' = 0.64 Brilliance [GU] 182.8 ± 0.36 18.9 ± 0.54 Not measured Not measured SCI color L ₁ * = 44.70 ± 0.02 L _1' * = 38.79 ± 0.05 Not measured Not measured a ₁ * = -0.02 ± 0.00 a _1' * = -0.04 ± 0.01 b ₁ * = -0.72 ± 0.00 b _1' * = -0.84 ± 0.03 SCE color L ₁ * = 0.00 ± 0.00 L _1' * = 37.68 ± 0.05 Not measured Not measured a ₁ * = 0.02 ± 0.01 a _1' * = -0.09 ± 0.01 b ₁ * = 0.01 ± 0.00 b _1' * = -0.90 ± 0.04

1. 1) Pour la surface granuleuse :
   1. a. Paramètre Ra (ISO 4287) représentant la hauteur moyenne (arithmétique) de la rugosité.
   2. b. Paramètre Str (ISO 25178) représentant le degré d'isotropie de la surface. La valeur de ce paramètre est comprise entre 0 et 1, proche de 0 signifie que la surface contient une direction privilégiée, alors que proche de 1, toutes les directions d'observation sont identiques.
2. 2) Pour la surface lisse, seul le paramètre Ra est retenu et représente la hauteur moyenne (arithmétique) de la rugosité.

As a note, the S parameters (Sa, Sdr, Sq, ...) are taken from the ISO 25178 standard and are not filtered. The R parameters (Ra Rp, Rz, ...) are taken from the ISO 4287 standard and have been filtered with a Gaussian filter whose cutoff is set at 0.25 mm. More precisely, the parameters selected for the roughness analysis are:

1. 1) For the granular surface:
   1. a. Parameter Ra (ISO 4287) representing the mean (arithmetic) height of the roughness.
   2. b. Str parameter (ISO 25178) representing the degree of isotropy of the surface. The value of this parameter is between 0 and 1, close to 0 means that the surface contains a preferred direction, while close to 1, all observation directions are identical.
2. 2) For the smooth surface, only the parameter Ra is retained and represents the average (arithmetic) height of the roughness.

1. 1) Pour la surface granuleuse :
   1. a. Paramètre Ra : Il est nécessaire d'utiliser un équipement de mesure avec une résolution verticale de 2 nm minimum et latérale de 0.26 µm. Le cut-off (λc) de la norme ISO 4287 sélectionné est de 0.25 mm, ce qui implique une longueur d'évaluation de l'ordre de 1.4 mm. La mesure est réalisée sur un nombre de profils supérieur à 1000. La valeur du paramètre livrée correspond à la moyenne réalisée sur l'ensemble des profils.
   2. b. Paramètre Str : Il est nécessaire d'utiliser un équipement de mesure avec une résolution verticale de 2 nm minimum et latérale de 0.26 µm. La mesure est réalisée sur 5 zones carrées ayant le même nombre de lignes et de colonnes (>1000). Une suppression de forme polynomiale (d'ordre 4) ainsi qu'un seuillage (compris entre 0.5 % et 99.5 %) sont réalisés sur les mesures. La valeur livrée correspond à la moyenne des 5 mesures.
2. 2) Pour la surface lisse, le calcul du paramètre Ra nécessite d'utiliser un équipement de mesure avec une résolution verticale de 0.2 nm minimum et latérale de 0.26 µm. Le cut-off (λc) de la norme ISO 4287 sélectionné est de 0.25 mm, ce qui implique une longueur d'évaluation de l'ordre de 1.4 mm. La mesure est réalisée sur un nombre de profils supérieur à 1000. La valeur du paramètre livrée correspond à la moyenne réalisée sur l'ensemble des profils.

Due to their technical definitions, these parameters are determined under distinct measurement conditions:

1. 1) For the granular surface:
   1. a. Ra parameter: It is necessary to use measuring equipment with a vertical resolution of at least 2 nm and a lateral resolution of 0.26 µm. The cut-off (λc) of the ISO 4287 standard selected is 0.25 mm, which implies an evaluation length of around 1.4 mm. The measurement is carried out on a number of profiles greater than 1000. The delivered parameter value corresponds to the average carried out on all the profiles.
   2. b. Str parameter: It is necessary to use measuring equipment with a vertical resolution of at least 2 nm and a lateral resolution of 0.26 µm. The measurement is carried out on 5 square areas with the same number of rows and columns (>1000). A polynomial form suppression (of order 4) as well as a thresholding (between 0.5% and 99.5%) are carried out on the measurements. The delivered value corresponds to the average of the 5 measurements.
2. 2) For the smooth surface, the calculation of the Ra parameter requires the use of measuring equipment with a vertical resolution of at least 0.2 nm and a lateral resolution of 0.26 µm. The cut-off (λc) of the ISO 4287 standard selected is 0.25 mm, which implies an evaluation length of around 1.4 mm. The measurement is carried out on a number of profiles greater than 1000. The delivered parameter value corresponds to the average carried out on all the profiles.

There figure 4 represents a photograph of a portion of the resulting watch component 10, seen from above at the interface between the first surface and the third surface 2 of a hollow. The top view allows the first surface 1 and the third surface 2 to be observed, as well as the location of the edge 4. The connecting surface is not visible. The first surface 1 is in the form of a matte ceramic, and the third surface 2 is in the form of a sandblasted ceramic covered with a PVD coating.

There Figure 5 represents the linear roughness profile at the interface represented by the figure 4 It allows us to see the difference in roughness between the third surface 2, i.e. the bottom of the hollows, and the first surface 1.

In a second embodiment, a watch component 10 made of ceramic, more precisely of yttria-containing zirconia, is a decorative plate. It has a first flat surface 1 in which crenellated recesses are made forming second surfaces set back from the first surface 1, comprising vertical or substantially vertical connecting surfaces ensuring the connection between the first surface 1 and third surfaces 2 each forming a bottom. Polishing is applied to the first surface 1 and the third surfaces 2 at the end of the first step. Then, a second tribofinishing step similar to that described in the first example is applied.

The roughness measurements Ra and their deviations, in nanometers, are detailed in the following table, as well as the gloss measured with the gloss meter and expressed in gloss units and the color expressed in the ClELab color space. 1 1' 2 2' Roughness Ra in nm R1 = 2.0 ± 0.2 R1' = 200 ± 20 R2 = 1.2 ± 0.1 R2' = 1.5 ± 0.1 Brilliance [GU] 182.8 ± 0.36 18.9 ± 0.54 182.8 ± 0.36 182.8 ± 0.36 SCI color L ₁ * = 44.70 ± 0.02 L _1' * = 38.79 ± 0.05 Not measured Not measured a ₁ * = -0.02 ± 0.00 a _1' * = -0.04 ± 0.01 b ₁ * = -0.72 ± 0.00 b _1' * = -0.84 ± 0.03 SCE color L ₁ * = 0.00 ± 0.00 L _1' * = 37.68 ± 0.05 Not measured Not measured a ₁ * = 0.02 ± 0.01 a _1' * = -0.09 ± 0.01 b ₁ * = 0.01 ± 0.00 b _1' * = -0.90 ± 0.04

The variation of the surface condition through the described finishing process may be accompanied by a change in color. For example, a black ceramic may become dark gray or a green ceramic may become dark green.

There figure 6 represents a photograph of a portion of the watch component 10 obtained, at the interface between the first surface 1 and the third surface 2 of a hollow. The top view allows the first surface 1 and the third surface 2 of a hollow to be observed, as well as the location of the edge 4. The connecting surface is not visible. The first surface 1 is in the form of a matte ceramic, and the third surface 2 is in the form of a polished ceramic.

There figure 7 represents the linear roughness profile at the interface represented by the figure 6 It allows us to see the difference in roughness between the third polished surface 2 forming the bottom of the hollows, and the first matte surface 1.

Finally, it therefore appears that the invention makes it possible to easily obtain different surface states, including a first uniformly finished surface 1 and a third polished or rough surface 2 forming the bottom of the hollow.

The invention also relates to a watch component 10 as such obtained by the method described above. This watch component 10 may be, for example, a bezel, a bezel disc, a casing element, a case, a back, a caseband, a dial, a bracelet link or a decorative plate. This component may also be a component of the movement, such as, for example, a date disc.

The watch component 10 therefore comprises a first surface 1, in which at least one hollow is arranged forming at least one second surface set back from the first surface 1. This at least one second surface comprises for example a third surface 2 forming a hollow bottom, and a connecting surface located between the first surface 1 and the third surface 2. The first surface 1 has a first surface state obtained by termination without having to protect the hollows while the media and/or abrasives are set in motion towards the hollows, this first surface state being different from the second surface state of at least a portion of the at least one hollow.

The watch component 10 may comprise a first surface 1 uniformly mattified by tribofinishing and a surface of a polished or rough hollow.

• plusieurs creusures de formes identiques ou différentes ; et/ou
• plusieurs creusures d'états de surface différents.

In addition, the component may include:

• several hollows of identical or different shapes; and/or
• several hollows with different surface conditions.

• la première surface 1 du composant peut être mate, ou peut comprendre des zones mate(s) et brillante(s) ; et/ou
• la surface d'une creusure peut comprendre un revêtement ; et/ou
• la rugosité de la première surface 1 peut être inférieure à la rugosité d'au moins une portion de la creusure ou la rugosité de la première surface 1 peut être supérieure à la rugosité de la creusure ; et/ou
• la rugosité de la première surface 1 peut être homogène et isotrope, par exemple comprise entre 100 nm et 10 µm (rugosité Ra), voire entre 100 nm et 800 nm.

Moreover :

• the first surface 1 of the component may be matte, or may comprise matte and glossy areas; and/or
• the surface of a hollow may comprise a coating; and/or
• the roughness of the first surface 1 may be less than the roughness of at least a portion of the hollow or the roughness of the first surface 1 may be greater than the roughness of the hollow; and/or
• the roughness of the first surface 1 can be homogeneous and isotropic, for example between 100 nm and 10 µm (roughness Ra), or even between 100 nm and 800 nm.

The invention also relates to a timepiece as such, in particular a watch, more precisely a wristwatch.

• satinage, brossage,
• Cerclage,
• Colimaçonnage,
• Perlage de différents types : Œil de Perdrix, pointillage, etc.,
• Soleillage.

Of course, the proposed finishing treatments can be applied to any type of initial surface condition, raw or prepared. As examples, these surface conditions can be of the directional type among:

• satin finishing, brushing,
• Strapping,
• Snailing,
• Beadwork of different types: Partridge Eye, stippling, etc.,
• Sunbathing.

• Microbillage,
• Grenage,
• Sablage,
• Grenaillage.

According to other examples, these surface states can be on the contrary of the isotropic type. Among these, some propose a maximized specular reflection, like a polishing, or a minimized specular reflection, among a:

• Microblasting,
• Granage,
• Sandblasting,
• Shot blasting.

For example, a bezel disc, which is a watch component 10 produced according to an embodiment of the invention. This bezel disc comprises a main surface 5, for example two-tone, comprising at least one polished zone 6 and at least one matt zone 7. To obtain such a result, the polished disc can be protected with a mask (for example a rigid metal mask) on an area 6 during the second tribofinishing step (here mattification from a polished surface state). The recesses 20 form indications, for example round, on the periphery of the bezel disc. These recesses have a coating to be able to present a predefined, clear and legible color. The surface state of these recesses is identical, regardless of their positioning within the at least one matt area or the at least one shiny area of the main surface 5 of the bezel disc.

It is interesting to note that in all cases, the finishing step is carried out in the presence of a hollow in the surface concerned, that is to say in the presence of a recessed relief in the first surface which is treated by the finishing step. Thus, even in the case where a coating is carried out in the hollow, this coating is of small thickness, and does not fill the entire height of the hollow, so that there always remains a hollow forming a recessed relief in the surface. This hollow is present before the start of the finishing step, as well as after this finishing step. As a note, this finishing step cannot therefore be compared to a polishing which would remove a surplus of material to form a continuous and relief-free surface, therefore without hollows, of a watch component. Indeed, in such a case, not only would the final component no longer have any hollows, i.e. no more recessed relief, contrary to the desired objective, but the surface condition would also be continuous since the entire surface would necessarily be treated identically by such polishing.

In all cases, the hollow represents a hollow relief portion arranged on a first surface. The surface of the hollow, or second surface, is understood to be its upper surface, that is to say oriented towards said first surface. It is arranged at a lower level than said first surface since the hollow forms a hollow relief, and is not covered by another material, that is to say it opens directly to the outside, at least at the time of the second termination step. During this termination step, at least one part, preferably the part of greater depth, retains an unchanged surface condition.

Naturally, the numerous embodiments and variants described above can be combined.

Claims (11)

1. Method of manufacturing a watch component (10) for a timepiece, characterized in that it comprises a first stage of manufacturing a watch component (10) comprising a first surface (1), in which there is arranged at least one recess (20), that is to say a surface recessed from the first surface (1), and characterized in that it comprises a second finishing stage of finishing the watch component, which changes the surface condition of the first surface (1) by reducing or minimizing its specular reflection by subjecting it to the mechanical action of an abrasive mixture by impacts, this abrasive mixture comprising media of which the dimension and/or the geometry is defined in such a way as to prevent all contact by the media with at least one portion of the recess (20) or in such a way as to prevent all contact by the media with the portion of the recess (20) positioned at a distance greater than a given distance d, leading to a change in the surface condition, more particularly the roughness, more particularly measured by the parameters Ra and/or Str, and/or the gloss, of the first surface (1) but not of the at least one recess (20) or of a portion of this at least one recess (20), said at least on recess comprises a recess surface, uncovered at the time of operating the second finishing stage, said recess surface keeping a surface condition unchanged at the end of said second finishing stage.
2. Method of manufacturing a watch component (10) for a timepiece as claimed in the preceding claim, characterized in that the second finishing stage changes the surface condition of the recess (20) over a distance d strictly lower than the depth of the recess (20).
3. Method of manufacturing a watch component (10) for a timepiece as claimed in one of the preceding claims, characterized in that the at least one recess comprises a third surface (2) forming a bottom surface connected to the first surface (1) by a connecting surface (3), and wherein the second finishing stage does not change the surface condition of the third surface (2) of the at least one recess (20).
4. Method of manufacturing a watch component (10) for a timepiece as claimed in one of the preceding claims, characterized in that the first stage of manufacturing comprises the manufacturing of a watch component (10) comprising a part based on technical ceramic, said recess (20) being located in said part based on ceramic.
5. Method of manufacturing a watch component (10) for a timepiece as claimed in one of the preceding claims, characterized in that the second finishing stage changes the surface condition of the first surface (1) in order to form a first surface (1) of homogeneous and isotropic topography.
6. Method of manufacturing a watch component (10) for a timepiece as claimed in one of the preceding claims, characterized in that it comprises an intermediate stage involving changing the surface condition of all or part of the principal surface (5) or of the first surface (1) and possibly of the at least one recess (20) by increasing or maximizing their specular reflection.
7. Method of manufacturing a watch component (10) for a timepiece as claimed in one of the preceding claims, characterized in that the second finishing stage changes the surface condition of the first surface (1) by subjecting it to the mechanical action of an abrasive mixture by impacts, by setting in vibratory, oscillatory or rotary motion, in a container.
8. Method of manufacturing a watch component (10) for a timepiece as claimed in one of the preceding claims, characterized in that :

   - the first stage of manufacturing a watch component (10) forms a second recess (21) in said at least one recess (20), and in that the second finishing stage leads to a change exclusively in the surface condition of the first surface (1); and/or in that

   - the first stage of manufacturing a watch component (10) forms a second recess (21) in said at least one recess (20), and wherein the finishing stage leads to a change in surface condition of the first surface (1) and of at least one portion of the at least one recess (20), but not of the second recess (21); and/or in that

   - the first stage of manufacturing a watch component (10) forms recesses (20, 20') having different geometries in the first surface (1), and in that the finishing stage leads to a change in the surface condition of the first surface (1), but not of said recesses (20, 20'); and/or in that

   - the first stage of manufacturing a watch component (10) forms first and second recesses (20, 20') having different geometries in the first surface (1), and in that the finishing stage leads to a change in the surface condition of the first surface (1) and of the second recess (20'), but not of the first recess (20) or of a portion exclusively of this first recess (20).
9. Method of manufacturing a watch component (10) for a timepiece as claimed in one of the preceding claims, wherein the first stage of manufacturing a watch component comprises the manufacturing of a technical ceramic-based homogeneous and single-piece component or comprising at least partially the combination of different parts made of ceramic.
10. Method of manufacturing a watch component (10) for a timepiece as claimed in one of the preceding claims, characterized in that it comprises an intermediate stage of manufacturing of a watch component (10) involving a stage of coating of the at least one recess (20), more particularly of a third surface (2) forming a bottom surface of the recess, in a mono-layer or multilayer fashion, more particularly by a stage by PVD, by CVD, by ALD, by LBL, by brush, by dispenser, by spraying, by nebulization, by ink-jet, by dip-coating, or by the sol-gel method.
11. Method of manufacturing a watch component (10) for a timepiece as claimed in the preceding claim, characterized in that the coating comprises a layer composed of metal (metals) and/or oxide(s) and/or nitride(s) and/or carbide(s) and/or nitrocarbide(s) and/or sulfide(s) and/or organic material(s), and/or inorganic material(s), and/or hybrid material(s), and/or a paint, and/or a lacquer, and/or an enamel, and/or a varnish and/or a vitroceramic, and/or a polymer-based or adhesive-based material.