Method for printing functional elements on a timepiece component

Abstract

The invention relates to a method for printing a functional element (2) on a surface (5) of a receiving area (3) of a timepiece component (1) of a timepiece (100), said functional element (2) contributing in particular to adjusting the operation of the timepiece (100) by modifying the inertia and / or the unbalance of the component (1), said method comprising the following steps: a preparation step (20) of preparing a solution comprising a material constituting the functional element (2), said preparation step (20) comprising a sub-step (21) of defining specific properties of the solution according to preparation criteria, said properties relating to the viscosity and the surface tension of the solution, and said preparation criteria comprising: at least one structural modification feature of the timepiece component (1); at least one construction feature of the functional element (2) on the receiving area (3), said at least one feature comprising the geometric dimensions of the functional element to be constructed and mechanical, chemical and aesthetic properties; at least one structural feature of the material to be applied to the receiving area, said at least one feature comprising aesthetic, physical and chemical properties, such as the density of the material; and at least one feature of the receiving area (3) of the component (1), such as the geometric dimensions of the surface of the receiving area to be covered by the functional element, the mechanical and chemical properties of the material constituting said area, such as the adhesion, the surface roughness, the surface energy and the surface tension properties of said surface of the receiving area; a deposition step (34) of depositing the prepared solution on said surface (5) of the receiving area.

Description

TECHNICAL FIELD

[0001] The present invention relates to a method for printing a functional element on the surface of a receiving area of a timepiece component of a timepiece, as well as such a timepiece component and such a timepiece. BACKGROUND

[0002] Various methods are known in the prior art for applying a material to a component of a timepiece, in particular when these methods aim to participate in regulating the rate of a timepiece movement by adjusting the inertia of a component of this movement, such as the balance of a balance spring resonator.

[0003] In this context, these methods generally envisage first determining a correction value of the moment of inertia to be applied to the balance in order to obtain the desired rate of the movement, said correction value being determined by establishing a measured value of the rate of the timepiece movement. Secondly, they envisage adding material by spraying this material onto the balance in order to adjust the moment of inertia of this balance according to the determined correction value.

[0004] However, one of the main drawbacks of such a method lies in the fact that such an addition of material by spraying often causes splashes, in particular due to the impact of this material on the balance, which can spread and contaminate the timepiece movement, leading to malfunctions of this movement. SUMMARY

[0005] It is therefore an object of the present invention to provide a method for applying a functional element precisely and selectively on a defined receiving area of a timepiece component, which can be for example a balance.

[0006] Another object of the present invention is to provide the possibility of regulating the rate of a timepiece comprising a resonator equipped with such a balance.

[0007] Another object of the present invention is to print a functional element consisting of a controlled quantity of material on a receiving area of a timepiece component.

[0008] To this end, the present invention relates to a method for printing a functional element on the surface of a receiving area of a timepiece component of a timepiece, which functional element contributes in particular to regulating the rate of the timepiece (100) by modifying the inertia and / or the unbalance of the component (1), said method comprising the following steps:

[0009] - a preparation step of preparing a solution comprising the material constituting said functional element, said preparation step comprising a sub-step of defining specific properties of the solution according to preparation criteria, said properties relating to the viscosity and the surface tension of this solution, and said preparation criteria comprising:

[0010] • at least one structural modification feature of the timepiece component;

[0011] • at least one construction feature of the functional element on the receiving area, said feature comprising the geometric dimensions of the functional element to be constructed, and mechanical, chemical and aesthetic attributes,

[0012] • at least one structural feature of the material to be applied to the receiving area, comprising aesthetic, physical and chemical attributes, such as the density of the material, and

[0013] • at least one feature of the receiving area of the component, such as the geometric dimensions of the surface of the receiving area that can be covered by the functional element, the mechanical and chemical attributes of the material that constitutes the area, such as the adhesion, surface roughness, surface energy and surface tension attributes of the surface of the receiving area,

[0014] - depositing the prepared solution on the surface of the receiving area.

[0015] In other embodiments:

[0016] - the preparation step comprises a sub-step of composing a mixture in relation to the solution according to the defined specific attributes of the solution, said sub-step comprising a phase of generating a base formulation containing the material and a base liquid, in particular a solvent;

[0017] - the composition sub-step comprises a phase of selecting at least one product to be added to the base formulation, said at least one product being selected from surface tension correction additives, such as wetting agents;

[0018] - the composition sub-step comprises a phase of selecting at least one product to be added to the base formulation, said at least one product being selected from dispersants that help with the dispersion stability of the particles of the solid material;

[0019] - the step of preparing the solution comprises a sub-step of mixing at least one selected product with the base formulation;

[0020] - the deposition step comprises a sub-step of applying the prepared solution to the entire surface of the receiving area;

[0021] - the application sub-step is performed using a printing technology of the following type: "aerosol jet", "high-density inkjet", "pneumatic dispensing", "extrusion dispensing" or "super inkjet";

[0022] - when the printing technology uses aerosol jet, the application sub-step comprises a phase of converting the prepared solution into an aerosol;

[0023] - the deposition step comprises a sub-step of solidifying the material of the solution applied to the surface of the receiving area;

[0024] - said solidification sub-step begins simultaneously or substantially simultaneously with the application sub-step and ends after the application sub-step has been completed;

[0025] - said defining sub-step comprises a phase of determining said at least one structural modification feature of the timepiece component;

[0026] - said defining sub-step comprises a phase of determining said at least one construction feature of the functional element on said receiving area, said construction feature comprising the geometric dimensions of the functional element to be constructed, and / or mechanical, chemical and / or aesthetic properties;

[0027] - said defining sub-step comprises a phase of determining said at least one structural feature of the material to be applied to said receiving area, said structural feature comprising aesthetic, physical and / or chemical properties, such as the density of said material;

[0028] - said defining sub-step comprises a phase of determining features of the receiving area of the timepiece component, said features of the receiving area comprising the geometric dimensions of the surface of said receiving area that can be covered by said layer, and / or the mechanical and / or chemical properties of the material constituting this area, such as the adhesion, surface roughness and / or surface tension properties of the surface of said receiving area;

[0029] - a particular property of said defining sub-step also relates to the density of said solution;

[0030] - said material comprises at least one molecular precursor or at least one particle, such as a metallic or metal oxide particle, a single or polycrystalline particle, an amorphous material particle, a ceramic particle, a polymeric particle, a colored particle, an uncolored particle, a translucent / transparent particle, a fluorescent particle or a phosphorescent particle;

[0031] - said material comprises at least one particle of the nanoparticle or microparticle type;

[0032] - said functional element applied to the surface of the receiving area of the timepiece component of the watch comprises a decorative / aesthetic element, an element for adjusting the operation of the timepiece component, such as an inertial mass, or an interface element;

[0033] - said method comprises a step of repeating said deposition step;

[0034] - said method is a method for printing a functional element on the surface of a receiving area of a timepiece component, in particular by aerosol jetting, said functional element contributing in particular to adjusting the timekeeping of the watch by modifying the inertia and / or the unbalance of the component.

[0035] The invention also relates to a timepiece component comprising at least one receiving area provided with a surface on which a functional element can be applied using said method.

[0036] Advantageously, said component is a balance wheel of a timepiece, comprising an adjustment face provided with said at least one receiving area, which can comprise a functional element for adjusting the rate of the balance wheel, in particular by modifying the inertia and / or the unbalance of the balance wheel.

[0037] In particular, the surface of each receiving area is non-planar.

[0038] The invention also relates to a timepiece comprising such a component. BRIEF DESCRIPTION OF DRAWINGS

[0039] Other specific features and advantages will become apparent from the following description, given as a mere illustrative and non-limiting example, with reference to the enclosed drawings, wherein:

[0040] - Figure 1 and 2 each show a top view of two alternative embodiments of a timepiece component, for example in this case a balance wheel comprising receiving areas each intended to receive a functional element, according to an embodiment of the invention;

[0041] - Figures 3 to 5 show cross-sectional views of three alternative embodiments of a receiving area according to embodiments of the invention;

[0042] - Figure 6 show a schematic view of a timepiece comprising such a timepiece component provided with a receiving area comprising a functional element, according to embodiments of the invention, and

[0043] - Figure 7 show a flowchart of a method relating to printing a functional element on a receiving surface of each receiving area of a timepiece component, according to embodiments of the invention. DETAILED DESCRIPTION

[0044] With reference to Figures 1 to 7 , the invention relates to a method for printing a functional element 2 on a receiving surface 5 of a receiving area 3 of a timepiece component 1 of a timepiece 100. It should be noted that such a method is preferably an aerosol jet printing method. However, it will be understood that in other embodiments, the method can implement other printing technologies, such as high-density inkjet, pneumatic dispensing, screw-driven extrusion dispensing or super inkjet technology. The method can also implement a printing technology which envisages the use of a spattering device such as micro-droplets to deposit dot beads. For such a printing technology, the dots can be arranged close enough together to form the functional element 2 in the form of a continuous line.

[0045] This method is particularly intended to ensure that the functional element 2 printed on the surface 5 of the receiving area 3 is a functional element 2 having a functional application only in the field of horology. The functional element 2 is for example a decorative / aesthetic element, an element for regulating the operation of a horological component, such as an inertial mass, an interface element or an element for the unambiguous identification of a horological component.

[0046] The functional element 2 is formed from a solid material which can comprise, in a non-limiting and non-exhaustive manner, at least one molecular precursor or at least one particle, such as a metallic or metal oxide particle, a single or polycrystalline particle, such as alumina or silicon, an amorphous material particle, such as glass, a metal, etc., a ceramic particle, a polymeric particle, a pigmented / coloured particle, an uncoloured particle, a translucent / transparent particle, a fluorescent particle or a phosphorescent particle. It should also be noted that the particles can be of the nanoparticle or microparticle type.

[0047] For a better understanding of the application, an embodiment is described herein in which the functional element 2 printed on the surface 5 of the receiving area 3 forms a regulating element of the inertial mass type. The inertial mass 2 can contribute to adjusting the rate of the watch, in particular by modifying the inertia and / or the unbalance of the horological component 1 of the watch 100, in this case the balance. In this context, the application also allows the inertia and / or the unbalance of a single hairspring balance mechanism or of a hairspring balance mechanism installed in the movement 110 of the watch 100 to be corrected, the movement 110 being able to be installed in the case of the watch during the correction operation. It can be clearly understood that all the operations implemented within the scope of the printing method described below remain the same regardless of the type of functional element 2 to be printed on the receiving area 3.

[0048] Thus, in this context, Figure 1 A balance 1 of a resonator 120 of the balance wheel type of a movement 110 of a watch 100 is shown. Such a balance wheel 1 is provided with said at least one receiving area 3 intended to receive a functional element 2 for adjusting the rate of the watch 100 and thus of its movement 110. Such a receiving area 3 can comprise:

[0049] - a recess defined in the top face 4a of the balance wheel 1, as shown in Figures 1 to 4 , or

[0050] - a recess not shown in the figures, defined in the bottom face 4d and / or the first side face 4b and / or the second side face 4c of the balance wheel 1, or

[0051] - a portion of the surface of the top face 4a and / or the bottom face 4d and / or the first side face 4b and / or the second side face 4c of the balance wheel 1, as shown in Figure 1 , 2 and 5.

[0052] The first side face 4b and the second side face 4c respectively correspond to an outer peripheral wall and an inner peripheral wall of the outer wheel 11. The receiving area 3 comprises a receiving surface 5 of the functional element 2, which receiving surface 5 can be:

[0053] - planar, as in the alternative embodiment of the receiving area 3 shown in Figure 3 , or

[0054] - non-planar, as curved, as shown in Figure 4 , or comprising sub-surfaces connected to each other in a perpendicular or substantially perpendicular manner, as shown in Figure 5 .

[0055] It is further noted that the receiving surface 5 is defined on all or part of the receiving area 3.

[0056] In Figure 1 and 2 , the balance wheel 1 comprises an outer wheel 11, a hub 12 intended to be rotatably mounted on a balance shaft, and one or more arms 13, for example two, three or four arms 13, connecting the outer wheel 11 to the hub 12. The balance wheel 1 comprises an adjustment face comprising at least one receiving area 3 for receiving a functional element 2. This adjustment face in particular comprises a top face 4a and / or a bottom face 4d and / or a first side face 4b and / or a second side face 4c. When the balance wheel 1 is contained within a watch movement 110, for example mounted inside a watch case, this adjustment face is preferably oriented towards the back cover of the watch case of the watch 100, and such that each receiving area 3 is accessible for printing a functional element 2 on its receiving surface 5. It is noted that the top face 4a comprises a first portion contained / defined in the outer wheel 11 of the balance wheel 1, and a second portion in the arms 13 of this balance wheel 1. Such a top face 4a is planar or substantially planar, and extends in a plane orthogonal to the balance shaft.

[0057] As previously mentioned, with reference to Figure 3 and 4 , the receiving area 3 can be a recess, for example a groove, a cavity or a concave structure, provided with an opening, with a solid bottom that can comprise a substantially planar surface and an inner wall connecting said opening to said bottom. Herein, “solid bottom” must be understood to mean a bottom without any opening / aperture. In this configuration, the receiving surface 5 is formed by the bottom of this recess, as in Figure 3 , or by the bottom and a portion of the inner wall, as in Figure 4 . In these Figure 3 and 4In the example shown, the recesses are defined only in the top face 4a of the balance wheel 1, in particular in the outer wheel 11, so that this top face 4a comprises a plurality of openings allowing access to the interior space of the respective recess. In this configuration, each recess, and thus each respective interior space, is intended to receive a functional element 2 acting as an inertial mass in order to modify the inertia and / or the unbalance of the balance wheel 1.

[0058] In an alternative not shown, the recesses can be through and form through-holes or blind holes, thus comprising openings at both ends thereof. In this configuration, the receiving surface is formed by the inner wall of the recess.

[0059] In Figure 5 In another alternative shown, the receiving area 3 is not a recess, and can thus be defined on both a portion of the surface of the top face 4a (or of the bottom face 4d) and a portion of the surface of one of the two side faces 4b, 4c. In another alternative, the receiving area 3 can be located on a portion of the surface of the top face 4a or of the bottom face 4d only, or on a portion of the surface of the side faces 4b, 4c only.

[0060] In another alternative, the receiving area 3 can be located:

[0061] - on both a portion of the surface of the top face 4a and a portion of the surface of the two side faces 4b, 4c, or

[0062] - on both a portion of the surface of the bottom face 4d and a portion of the surface of the two side faces 4b, 4c.

[0063] The receiving area 3 can be defined in / on the outer wheel 11 of the balance wheel 1 or in / on one of the arms 13. If the balance wheel 1 comprises a plurality of receiving areas 3, these receiving areas 3 can be distributed in / on the arms 13 of the balance wheel 1 only, or in / on the outer wheel 11 of the balance wheel 1 only, or in / on the arms 13 and the outer wheel 11 of the balance wheel 1. Alternatively, if the balance wheel 1 comprises a single receiving area 3, this single receiving area 3 can be defined in the adjustment face over the entire profile of the outer wheel 11.

[0064] In Figure 1 In this case, the outer wheel 11 comprises a plurality of receiving areas 3, for example three areas 3, distributed around the periphery of the outer wheel 11. Each receiving area 3 extends in the form of a circular arc, the angle of the circular arc being for example between 5° and 120°, preferably between 20° and 60°. In Figure 2 In this case, the outer wheel 11 comprises a plurality of receiving areas 3, for example four areas 3 or more, distributed around the periphery of the outer wheel 11. These receiving areas 3 extend in the form of a circular arc, the angle of the circular arc being less than 90°, preferably less than 45°. It will be understood that the application can also be implemented as an outer wheel comprising a single receiving area 3 or two receiving areas 3 or more than three receiving areas 3.

[0065] In these two embodiments, the reception areas 3 can be distributed uniformly around the periphery of the outer wheel 11 of the balance wheel 1, for example, to obtain a symmetrical distribution of the printed functional elements 2 in all the reception areas 3 or in some of them, in order to modify the inertia and / or the unbalance of the balance wheel 1, in order to precisely adjust the rate of the movement 110. In yet another example, the reception areas 3 in the two above-mentioned embodiments can be distributed asymmetrically around the periphery of the outer wheel 11, in order to modify the inertia and / or the unbalance of the balance wheel 1 and of its center of mass, by printing the functional elements 2 in all the asymmetric reception areas 3 or in some of them. In another example, the reception areas 3 of the balance wheel 1 are distributed symmetrically on the outer wheel 11 of the balance wheel 1 and the functional elements 2 are printed only in some of these reception areas 3, said some of the reception areas 3 having an asymmetric configuration with respect to each other.

[0066] As mentioned above, each reception area 3 opens onto the adjustment face of the balance wheel 1, which, when this adjustment face is constituted only by the top face 4a and / or the two side faces 4b, 4c, is intended to be arranged substantially facing the back cover of the case of the watch 100, in the case where the movement 110 is installed inside the case of the watch 100. Thus, in such a configuration, when the movement 110 is installed in the intermediate piece of the watch 100, the rate of the movement 110 can be adjusted finally, before assembling the case back cover with the intermediate piece, by adjusting the means for applying the functional elements 2 above the balance wheel 1, while ensuring, for automatic type movements, the disengagement of the balance of the watch 100 from the resonator 120 of the movement 110. In this embodiment, the spraying device can implement an aerosol jet type printing technique, which allows very precise vaporization with very small volumes of material.

[0067] Figure 7 A method for printing functional elements 2 on the surface 5 of the reception areas 3 of a component 1 of a watch 100 is shown. More particularly, in the embodiments of the application described here, printing such functional elements 2 on a component 1 of a watch, a balance wheel 1 or even a hairspring balance wheel mechanism, contributes to adjusting the rate of the watch 100. Under these conditions, this method is also a method of printing functional elements 2 on the surface 5 of the reception areas 3 of this component 1 of a watch 100, in particular by aerosol jet, which contributes to adjusting the rate of the watch 100, in particular by modifying the inertia and / or the unbalance of this component 1.

[0068] Such a method comprises a step 20 of preparing a solution comprising said material constituting the functional element 2 to be printed on the timepiece component 1. This solution can be more or less in a paste or viscous liquid state. In this embodiment, said solution comprising the material can thus be an ink, i.e. a liquid solution which, after its deposition on the receiving area 3, can be dried by evaporation or solidified by polymerization to ensure the application of a solid material onto said area 3.

[0069] This preparation step 20 comprises a sub-step 21 of defining specific properties of the solution according to preparation criteria. In this sub-step 21, the specific properties of the solution relate to the viscosity and the surface tension of the solution. In this embodiment, these properties also relate to the density of said solution. The preparation criteria comprise:

[0070] • at least one structural modification feature of the timepiece component 1 ;

[0071] • at least one construction feature of the functional element 2 on said receiving area 3;

[0072] • at least one structural feature of the solid material constituting the functional element 2 to be applied to said receiving area 3;

[0073] • at least one feature of said receiving area 3 of the component 1 ; and

[0074] • at least one feature of the printing technique implemented by the present method.

[0075] The defining sub-step 21 comprises a phase 22 of determining said at least one structural modification feature of the timepiece component 1. In the context of this embodiment of the application, wherein the application of the functional element 2 to this component 1 is intended to adjust the rate difference of the timepiece 100, said at least one structural modification feature comprises a rate difference correction value resulting from a correction value for correcting the inertia and / or the unbalance of the balance wheel 1 in order to obtain an adjusted / corrected rate difference of the timepiece movement 110 and thus of the timepiece 100.

[0076] Furthermore, in the context of this embodiment of the application, wherein the application of the functional element 2 to this component 1 is intended to adjust the rate difference of the timepiece 100, this determination phase 22 comprises a sub-phase 23 of measuring the rate difference of the timepiece movement 110. This measurement can preferably be carried out without contact, since the access to the resonator is particularly narrow. In a known manner, the measurement of the rate difference of the movement 110 can thus be carried out using optical and / or acoustic techniques, for example. This measurement sub-phase 23 allows to compare the measured rate difference with the desired rate difference. In addition, it also makes it possible to know the beat of the balance wheel 1 so that the balance wheel 1 can be synchronized with the printing of the functional element 2 on the receiving surface 5 of each receiving area 3 of the balance wheel 1.

[0077] Moreover, in the context of this embodiment aimed at adjusting the rate difference of the timepiece 100, the determining phase 22 subsequently comprises a sub-phase 24a of estimating a correction value of the inertia of the balance wheel 1 to obtain a corrected rate difference. This correction value is determined by the following known formula:

[0078] For a resonator of the type of a hairspring balance wheel mechanism, the moment of inertia I of the balance wheel satisfies the following formula:

[0079] I = mr 2 (1)

[0080] where m is the mass of the balance wheel 1 and r is its radius of gyration, which also depends on the temperature by the coefficient of thermal expansion of the balance wheel 1.

[0081] Moreover, the elastic moment C of the isosceles hairspring satisfies the following formula:

[0082]

[0083] where E is the Young's modulus of the material used, h is its height, e is its thickness and L is its developed length.

[0084] Finally, the frequency f of the resonator 120 comprising a hairspring balance wheel mechanism satisfies the following formula:

[0085]

[0086] The determining phase 22 also comprises a sub-phase 24b of estimating a correction value of the unbalance of the balance wheel 1 to obtain a corrected rate difference. The estimation of such a correction value is well known in the prior art, in particular described in documents WO2012007460 and EP2864844A1.

[0087] Subsequently, the defining sub-step 21 comprises a phase 25 of determining the at least one construction feature of the functional element 2 on the receiving area 3. During this phase 25, the construction features of the functional element 2 are determined, such as the geometric dimensions and / or the mechanical, chemical and / or aesthetic properties. It should be noted that the geometric dimensions of the functional element 2 determined here specifically relate to the thickness, length, width and / or radius of this functional element 2, thus allowing the correction value of the rate difference to be defined. The functional element 2 constructed on the receiving area can have a rectangular cross-section or a cross-section representing a portion of a disc. In this case, the cross-section depends on the surface tension of the solution and on the receiving surface of the receiving area 3.

[0088] This defining sub-step 21 also comprises a phase 26 of determining said at least one structural feature of the material to be applied to said receiving area 3. During this phase 26, the structural features of the material are determined, for example the aesthetic, physical and / or chemical properties, such as the density and the surface tension. It should be noted that the density of the material is that of the same material that will constitute the functional element 2 printed on the receiving area 3, and thus after solidification of this element 2 on this area 3, in particular after evaporation of the solvent of the solution.

[0089] This defining sub-step 21 also comprises a phase 27 of determining said at least one feature of said receiving area 3 of the component 1. During this phase 27, the features of the receiving area 3 are determined, for example the geometric dimensions of the surface of the receiving area 3 that can be covered by the functional element 2, and / or the mechanical and / or chemical properties of the material constituting this area 3, for example the adhesion and / or the surface roughness and / or the surface energy and / or the surface tension properties of the surface 5 of this receiving area 3.

[0090] Furthermore, as mentioned above, the printing method can implement various printing techniques. Under these conditions, such a method provides, during the defining sub-step 21, a phase 28 for determining at least one feature of the printing technique implemented in the method. This phase 28 thus allows the printing technique used to be identified.

[0091] These determination phases given the references 25, 26 and 27 are preferably carried out experimentally on a substrate equivalent to the receiving surface 5 of the receiving area 3 of the timepiece component 1 to be transformed. In a non-limiting and non-exhaustive manner, these phases can provide the following operations: observation under an optical microscope, carrying out an adhesion test, optical or mechanical profilometry, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), surface energy measurement for a substrate based on a reference liquid (for example water, ethylene glycol), surface tension measurement of the solution and / or wettability test, for example measurement of the contact angle between the solution and the substrate constituting the receiving area 3.

[0092] Then, the defining sub-step 21 comprises a phase 29 of generating the specific properties of the solution according to the preparation criteria estimated in the preceding determination phases 25, 26, 27, 28. It should be remembered that these preparation criteria in particular allow the quantity and the nature of the solid material to be applied to the surface of the receiving area of the timepiece component to be determined, the viscosity, the surface tension and the density properties being estimated in relation to said quantity and nature of the material. It should in particular be noted that the quantity and the nature of the material are decisive in particular for the density and viscosity properties and for the choice of additives that contribute to defining the surface tension of the solution.

[0093] In this production phase 29, the viscosity property of the solution determined according to the preparation criteria must be sufficiently high to prevent the spreading or even the bursting of the droplets due to the spraying of the solution outside the target receiving area 3 for printing the solution. Thus, the viscosity property is established taking into account the size of the receiving area 3 and, in certain alternative embodiments, also the aesthetic criteria regarding the final appearance of the functional element 2. For example, for a receiving area 3 whose width is limited to approximately 100 pm, the viscosity property of the solution determined limits the viscosity to be higher than 1 cP, preferably higher than 50 cP. It should also be noted that, depending on the type of printing technique implemented in the printing method, a very high viscosity can hinder the correct execution of the method, in particular by modifying the printing speed implemented therein. For example, in the field of aerosol jet printing, a viscosity exceeding 1,000 cP can prevent the generation of the aerosol jet.

[0094] As regards the surface tension property of the solution, this property is adjusted during the production phase 29 in correspondence with the surface energy of the substrate in the receiving area 3. The surface tension of the solution is preferably lower than the surface energy of the substrate. This condition can be analyzed by measuring two quantities. For example, the surface energy of the substrate can be measured according to the contact angle with a reference solvent, for example water, ethylene glycol or diiodomethane. The surface tension of the solution can be determined, for example, by the pendant drop method. Alternatively, the contact angle between the solution and the substrate can be measured directly. In general, the goal is to obtain a good wettability, i.e. a contact angle comprised between 0° and 90°. To obtain this condition, the surface tension of the solution can be influenced by adding wetting agents (surface tension correction additives) or by modifying the substrate of the receiving area to change its surface energy. When this modification of the substrate is controlled spatially, it offers the additional benefit of defining the receiving area 3.

[0095] The property related to the density of the solution is mainly determined by the mass fraction of the solid material constituting the solution and by the intrinsic density of this material. It should be understood that a solution of high density allows a faster addition of mass to the watch component to be treated, which is an advantage in terms of industrialized production. On the other hand, the quantity of solid material also determines the viscosity, a too high quantity limiting the precision or even the possibility of printing.

[0096] Subsequently, the preparation step 20 comprises a sub-step 30 of composing a mixture related to said solution according to the specific properties previously defined with reference to this solution. Such a sub-step 30 comprises a phase 31 of producing a base formulation comprising said solid material according to the properties and quantities previously determined, and a base liquid, for example a solvent or a mixture of various solvents. Subsequently, the sub-step 30 comprises a phase 32 of selecting at least one product to be added to said base formulation, said at least one product being chosen from the following products:

[0097] - surface tension correction additives, for example wetting agents, and / or

[0098] - a dispersant that contributes to the dispersion stability of the particles of the solid material.

[0099] Next, the step 20 of preparing the solution can optionally comprise a sub-step 33 of mixing at least one selected product with the base formulation. In this sub-step 33, one or more corrective additives and / or dispersants are added to the base formulation, according to the specific properties predefined for the solution. More particularly, during this mixing sub-step 33, the solution should be obtained in such a way that:

[0100] - the viscosity of the solution is adjusted according to the determined viscosity, by varying the proportions of one or more selected products of the mixture (mainly the solvent) according to the number and nature of the materials; and;

[0101] - the surface tension of the solution is adjusted according to the determined surface tension, by varying the proportions of one or more selected products of the mixture (mainly the additives) according to the number and nature of the materials;

[0102] - the density of the solution is adjusted according to the determined density, by varying the proportions of one or more selected products of the mixture (mainly the number of particles) according to the number and nature of the materials.

[0103] Subsequently, the method comprises a step 34 of depositing the prepared solution on the entire surface 5 of the receiving area 3. In this embodiment, such a step 34 contributes to the construction of the functional element 2 on the one or more receiving areas 3 of the balance wheel 1, in order to modify the inertia and / or the degree of unbalance of the balance wheel 1 according to the chronometric correction value. The deposition step 34 comprises a sub-step 35 of applying the prepared solution to the entire surface 5 of the receiving area 3 of the component 1. Such a sub-step 35 contributes to the application of the solution containing the materials to the component 1 in order to construct the functional element 2. Such an application sub-step 35 comprises a phase 36 of transforming the prepared solution into an aerosol when the printing technique uses aerosol jetting. This phase 36 comprises a sub-phase 37 of vaporizing the prepared solution, which contributes to the transformation of the solution into an aerosol.

[0104] The deposition step 34 then comprises a sub-step 38 of solidifying the materials of the solution applied to the surface of the receiving area 3. This sub-step 38 aims to complete the construction of the functional element 2 applied to the receiving area 3 of the component 1. This sub-step 38 can comprise starting the continuous evaporation of the solvent of the solution, the thermal solidification of the materials making up the functional element 2, or the cross-linking of the materials on the surface 5 of the receiving area 3 as soon as the application sub-step 35 is implemented. As mentioned above, this solidification sub-step 38 is preferably started simultaneously or substantially simultaneously with the application sub-step 35 and ends after the application sub-step 35 has been completed, in order to improve the positioning accuracy of the functional element 2 in the receiving area 3.

[0105] The method can provide a step 39 of repeating the deposition step 34 as many times as necessary to structure the functional element 2 on the receiving area 3 of the timepiece component 1. This functional element 2 can be monolithic or can be formed from a plurality of separate parts, for example a series of points separated from one another.

[0106] Thus, in particular because of the preparation and the specific composition of the solution comprising the material to be applied to the timepiece component 1, the method advantageously allows the functional element 2 to be printed on the component 1 in a targeted manner and with high precision. In terms of positioning, a deposition centring precision of the order of 5 pm can be achieved. This is more limited by the micro-positioning motor system than by the final mixture jetting target orientation. The quantity of material added can be controlled in the nanogram range, well below the sensitivity threshold in watchmaking applications.

[0107] Furthermore, this printing of the functional element 2 of the inertial mass type is performed in such a way that no splashes / sputters are produced after the deposition, as is desirable for the production of timepiece components 1, and the inertial masses deposited are highly controlled. It should be noted that the production of such splashes / appendages during the deposition is generally a cause of contamination of the timepiece movement 110 and of potential malfunctions thereof. Furthermore, the method allows the material to be applied uniformly on the timepiece component 1 and thus allows the mass of material to be distributed uniformly on the timepiece component 1, regardless of whether the surface 5 of the receiving area 3 is planar or non-planar. In other words, the functional element 2 is able to be printed uniformly with the same resolution on the entire three-dimensional receiving surface 5 of a timepiece component 1 that is stationary or in motion. It should furthermore be noted that such a solution thus designed also contributes to:

[0108] - geometrically defining the position of the functional element 2 on the surface 5 of the receiving area 3;

[0109] - improving the aesthetics of the functional element 2 on the receiving surface 5;

[0110] - facilitating the adhesion of the functional element 2 to the surface 5 independently of any preparation of this surface 5;

[0111] - proposing a repeatable printing method, and

[0112] - proposing a printing method that can be industrialized.

[0113] In one example, such an invention can be implemented in the range of adjusting the moment of inertia of a balance spring type of watch resonator, this adjustment aiming at correcting the rate of the oscillator in the order of -5 seconds per day. It is first to be understood that the negative sign here indicates that the rate correction can only be made by lowering the oscillation frequency, since the added material in the invention can only increase the moment of inertia of the balance. In this context, if one considers the mass and the outer radius of a standard watch balance, it can be deduced that the printing of a functional element on the outer rim of the balance, containing a solid material of mass approximately 10 micrograms, will allow to achieve such a correction of the rate in the order according to the above. To this end, the solution containing the functional element comprises:

[0114] - 95% by weight of a base formulation, i.e.:

[0115] • 20% by weight of a solvent, such as water, and

[0116] • 75% by weight of a solid material, such as at least one tungsten carbide nanoparticle, produced by US Nanomaterials Research Corporation and having a size comprised between 150 nm and 200 nm, and

[0117] - 5% by weight of a wetting agent, such as a polyurethane additive produced by Lubrizol under the trademark .

[0118] This solution is configured for a printing technology of the "aerosol jet" type, allowing a solid material flow rate of approximately 2 pg of tungsten carbide per second. The viscosity and the surface tension of the solution allow the deposit to be targeted on an arc of the balance outer rim with a thickness of 300 pm. Thus, it is possible to correct the rate of a watch resonator in the range of a few seconds. It is furthermore to be noted that using 75% by weight of tungsten carbide (density of 15.6 g / ml), 25% by weight of water and 5% by weight of polyurethane additive (density of approximately 1 g / ml), the density of the solution here is approximately 3.4 g / ml.

Claims

1. A method for printing a functional element (2) on a surface (5) of a receiving area (3) of a clock component (1) of a clock (100), the functional element (2) contributing to adjusting the timekeeping error of the clock (100) by changing the inertia and / or imbalance of the component (1), the method comprising the steps of: - A preparation step (20) for preparing a solution comprising the materials constituting the functional element (2), the preparation step (20) comprising a sub-step (21) for defining specific properties of the solution according to preparation criteria, the properties relating to the viscosity and surface tension of the solution, and the preparation criteria comprising: • Structural modification features of the clock component (1); • The construction features of the functional element (2) on the receiving area (3), the construction features including the geometry of the functional element to be constructed and its mechanical, chemical and aesthetic properties; • The structural characteristics of the material to be applied to the receiving region, including aesthetic, physical, and chemical properties, including the density of the material; and The characteristics of the receiving area (3) of the component (1) include the geometry of the surface of the receiving area that can be covered by the functional element, and the mechanical and chemical properties of the material constituting the area, including the adhesion, surface roughness, surface energy, and surface tension properties of the surface of the receiving area. -Deposition step (34) using a spraying device to deposit the prepared solution onto the surface (5) of the receiving area. And, the defining sub-step (21) includes a stage (29) of generating specific properties of the solution based on the preparation criteria estimated in the defining stages (22, 25, 26, 27, 28): -Structural modification features of the clock component (1); - The structural features of the functional element (2) on the receiving area; -The structural features of the material to be applied to the receiving area (3); -The characteristics of the receiving area (3) of the component (1); - Features related to the printing technology implemented in the method, And, during the generation phase (29): - The viscosity properties of the solution are determined according to these preparation criteria, and the viscosity properties are high enough to prevent droplet spread or even bursting due to spraying the solution outside the target receiving area (3) for printing the solution. The viscosity properties are established by taking into account the size of the receiving area (3) and aesthetic criteria regarding the final appearance of the functional element (2). - The surface tension property of the solution is adjusted according to the surface energy in the receiving area (3) of the clock component, wherein the surface tension of the solution is lower than the surface energy in the receiving area (3).

2. The method according to claim 1, characterized in that, The preparation step (20) includes a composition sub-step (30) of composing a mixture of solutions according to the specific properties of the solution as defined, the composition sub-step (30) including a stage (31) of generating a base formulation containing the material and a base liquid.

3. The method according to claim 2, characterized in that, The composition sub-step (30) includes a stage (32) of selecting at least one product to be added to the base formulation, said at least one product being selected from: - Surface tension correcting additives, and / or - A dispersant that contributes to the dispersion stability of particles in solid materials.

4. The method according to any one of claims 2-3, characterized in that, The step (20) of preparing the solution includes a sub-step (33) of mixing at least one selected product with the base formulation.

5. The method according to any one of claims 1-3, characterized in that, The deposition step (34) includes a sub-step (35) of applying the prepared solution to the entire surface (5) of the receiving region (3).

6. The method according to claim 5, characterized in that, The application sub-step (35) is performed using the following types of printing technology: aerosol jetting, high-density inkjet, pneumatic dispensing, extrusion dispensing, or super inkjet.

7. The method according to claim 6, characterized in that, When the printing technology uses aerosol jetting, the application sub-step (35) includes a stage (36) of converting the prepared solution into an aerosol.

8. The method according to claim 5, characterized in that, The deposition step (34) includes a sub-step (38) of solidifying the material of the solution applied to the surface of the receiving area (3).

9. The method according to claim 8, characterized in that, The curing sub-step (38) begins simultaneously or substantially simultaneously with the application sub-step (35) and ends after the application sub-step (35) has been completed.

10. The method according to any one of claims 1-3, characterized in that, The specific properties of the limiting sub-step (21) also relate to the density of the solution.

11. The method according to any one of claims 1-3, characterized in that, The material comprises at least one molecular precursor or at least one particle, wherein the at least one particle is a metal or metal oxide particle, a single crystal or polycrystalline particle, an amorphous material particle, a ceramic particle, a polymer particle, a colored / colored particle, a colorless particle, a translucent / transparent particle, a fluorescent particle, or a phosphorescent particle.

12. The method according to any one of claims 1-3, characterized in that, The material comprises at least one type of particle, either nanoparticles or microparticles.

13. The method according to any one of claims 1-3, characterized in that, The functional element (2) of the surface (5) of the receiving area (3) of the clock component (1) of the clock (100) includes decorative / aesthetic elements, elements for adjusting the operation of the clock component, or interface elements.

14. The method according to any one of claims 1-3, characterized in that, The method includes step (39) of repeating the deposition step (34).

15. The method according to any one of claims 1-3, characterized in that, The method is a method of printing functional elements (2) on the surface (5) of the receiving area (3) of the component (1) of the clock (100) by aerosol spraying, the functional elements (2) helping to adjust the timekeeping difference of the clock (100) by changing the inertia and / or imbalance of the component (1).

16. A watch component (1) comprising at least one receiving region (3) having a surface (5) on which a functional element (2) can be applied by means of any of the preceding claims.

17. The watch component (1) according to claim 16, characterized in that, The watch component is the balance wheel of a watch (100) and includes an adjustment surface having at least one receiving area (3), the receiving area (3) being capable of including the functional element (2) for adjusting the time difference of the balance wheel by changing the inertia and / or imbalance of the balance wheel.

18. The component (1) according to any one of claims 16-17, characterized in that, The surface (5) of each receiving area (3) is non-planar.

19. A clock (100) comprising a component (1) according to any one of claims 16 to 18.

Images