CH716663B1 - Process for manufacturing an epilamé mechanical part. - Google Patents

Abstract

The invention relates to a method for manufacturing an epilamé mechanical part (2) comprising a substrate (4) in a first material, the method comprising at least: a step (10) of depositing on the substrate (4) a epilame product (6) consisting of a second material, said deposition being carried out in the form of a projection onto the substrate (4) of at least one collimated or localized beam (12; 12A, 12B) of material containing the epilame product (6); and a step (11) for treating the second material to ensure the cohesion of the components on the substrate (4). The epilamé part can be a watch part.

Description

TECHNICAL FIELD OF THE INVENTION

The invention relates to a method of manufacturing an epilamé mechanical part.

The invention also relates to an epilamé mechanical part obtained according to such a manufacturing process. The mechanical part, which comprises a substrate on which a layer of epilame is deposited, is for example a part for watchmaking, typically a plate, an anchor lever, a wheel, a balance or even an axis.

STATE OF THE ART

[0003] In the field of mechanical components in frictional contact and in relative displacement, such as for example the field of watchmaking, the proper functioning of the mechanical parts depends, among other things, on their lubrication. The main function of a lubricant thus used is to separate the contacting surfaces in relative displacement while reducing energy dissipation and wear.

[0004] The lubricants used fall mainly into two categories: fluid lubricants and lubricants using so-called solid lubrication of mechanisms. Solid lubricants, which generally have a lamellar structure, are used less in the field of watchmaking than fluid lubricants, because they are intrinsically generators of debris. Such solid lubricants thus have the drawback of causing more or less long-term mechanical wear. However, such wear, which is difficult to predict, turns out to be very detrimental to the reliability of a watch movement.

[0005] Fluid lubricants are generally in the form of more or less viscous greases or oils. They have the advantage of being easier and faster to apply than solid lubricants. The volume of lubricant to be used is also more easily controllable. The physical characteristics of oils (viscosity, wettability, etc.) allow the lubrication of several functional areas of a mechanism, regardless of the complexity of the latter. The energy generated by heating is mainly dissipated by the oil. An oil film generally forms again, even after rupture and with a low volume used. The fluid must as much as possible remain confined in the functional zones whereas it naturally tends to spread out. The durability of the lubricant thus depends on its maintenance in the operating zone: any watchmaker has however observed that a drop of lubricant spreads quickly on a clean part. If this ability proves beneficial since all the sensitive areas of a mechanism are effectively covered, it can also prove detrimental to the proper functioning of the assembly. Indeed, a loss of oil in critical regions, typically areas of contact and relative movement of parts (functional areas), accentuated by a potential degradation of the latter under severe operating conditions, can cause irreversible damage. . In addition, the lubricant can get stuck in unwanted places and cause adhesion problems or, more generally, aesthetic problems.

[0006] The spreading of fluid lubricants, whether in the form of oils or greases, therefore poses a major problem for the operation of watch mechanisms. In the case of greases, we very often see a separation between the soap and the base oil. The latter will therefore be able to migrate onto the surfaces of the part and leave the functional zones, which brings us back to the problem mentioned above for fluid lubricants in the form of oils. In general, a fluid lubricant holds in place when its surface tension is higher than that of the support on which it is deposited. If the surface tension of the lubricant is too low, the oil spreads and does not stay in place.

[0007] In order to solve this problem, watchmakers deposit a coating called epilame on their components. This epilame, which often comes in the form of an invisible oleophobic molecular layer, is a product which reduces the apparent surface tension of the support. It should be noted that the surface tension given by an epilame is of the order of 20 to 30 mN/m, whereas the surface tension of a watchmaking oil is typically 35 mN/m. This difference of 5 to 15 mN/m gives a drop shape with an acceptable connection angle for watchmakers. It is usually around 25 to 60. This helps keep the lubricant in the desired area. A greater angle can lead to unwanted displacement (ball of lubricant rolling on the surface like water on new Gore-Tex™ for example).

[0008] This epilame can be deposited in several ways, but the method mostly known for doing this consists of soaking the mechanical part to be epilamed in a solution composed of a solvent and a certain quantity of molecules which will be deposited on the surface of the epilame. the part so as to modify its surface tension. The solvent is then evaporated in a subsequent step, leaving only the molecular layer of molecules deposited. The epilame then covers the entire surface of the part. In the first moments of operation and in the friction zones, the epilame is removed by abrasion, leaving a surface that the lubricant can wet. Some critical mechanisms like the escapement can be left running for a minimum amount of time for this epilame abrasion to occur. Once this operation is completed, a new lubrication is carried out. The lubricant then wets the surfaces where the abrasion was carried out exactly at the place of friction.

[0009] However, one of the major drawbacks of such a dipping deposition process is linked to the fact that it requires soaking a large quantity of parts in baths whose concentrations of "active" molecules decrease, which imposes a regular process monitoring and which leads to a possible technical risk of having too low a concentration and therefore too low an epilame effect. In addition, the epilaming solvents based on fluorinated compounds used by this process often contravene the standards in force, in particular provided for combating the emission of greenhouse gases. And finally, this process notably provides for too high a concentration of "active" molecules or a more ecological but less volatile solvent which can cause stains during the epilaming operation. However, they can be located far from the functional zones and therefore do not require epilaming.

[0010] In addition, such a method is likely to cause aesthetic problems on the part, due to poor evaporation of the solvent and/or concentration defects in the epilame. More generally, such a global dipping deposition process is relatively imprecise because it is not localized, and does not spare the contact zones.

SUMMARY OF THE INVENTION

[0011] The object of the invention is therefore to provide a method of manufacturing an epilame mechanical part allowing a local deposition of epilame on the part in order to delimit precise zones of confinement of a lubricant, and this in a simple manner. and inexpensive.

To this end, the invention relates to a method of manufacturing an epilamé mechanical part, which comprises the characteristics mentioned in independent claim 1.

[0013] Particular forms of the method are defined in dependent claims 2 to 16.

Thanks to the step of depositing in the form of projection on the substrate of at least one collimated or localized beam of material containing the epilame product, the method according to the invention allows a very precise deposition of epilame on the part. , both in volume of fluid deposited and in location. It is thus understood that, contrary to the methods of the prior art, the thin bead of epilame is here deposited locally on the part, which makes it possible to confine the lubricant in a zone delimited by the deposited bead. The surface thus delimited is then perfectly wetted by the lubricant, guaranteeing perfect operation for the part provided that the delimited zone corresponds to at least one targeted functional zone. It should be noted that, in the context of the present invention, the epilame product deposited can indifferently be an epilame product resulting in a grip or a repulsion of lubricant by physical effect, by chemical effect, or else via a combination between these two effects.

Advantageously, the deposition step comprises a phase of nebulization of an ink containing the epilame product in the form of a solution or suspension of particles, and a phase of spraying the nebulized ink onto the substrate of the part; and the step of treating the second material comprises a phase of hardening said second material. This process corresponds to the so-called AJP (Aerosol Jet Printing) process. It will be noted in an alternative, that certain inks did not require a hardening step, for example by crosslinking strictly speaking. A brief moment in the open air is enough for the solvent to evaporate and the resin to crosslink „all by itself“. Such a method offers a very wide variety in the choice of possible materials for the deposition of epilame product, and allows a very precise deposition, in particular at the micrometric scale on flat but also flexible and/or three-dimensional parts.

According to a particular technical characteristic of the invention, the hardening phase consists of a heat treatment which comprises at least one annealing step and/or a localized sintering step and/or a vacuum step. This speeds up the solidification process. In the case of an epilame product containing active components in solid and pulverulent form, such a heat treatment also makes it possible to melt the material to ensure cohesion between the grains.

According to another particular technical characteristic of the invention, the localized sintering step is obtained by irradiating said second material by means of a laser.

According to another particular technical characteristic of the invention, the curing phase consists of polymerization by photo-crosslinking and/or by chemical cross-linking.

According to another particular technical characteristic of the invention, the phase of polymerization by photo-crosslinking is obtained by the projection of ultraviolet rays onto the material containing the epilame product, at a predetermined wavelength.

According to another particular technical characteristic of the invention, the step of processing said second material comprises at least one of the following phases: a phase of modifying the chemical structure of the material containing the epilame product, in particular an ion implantation phase; a phase of modification of the crystallographic structure of the material containing the epilame product, in particular a phase of localized heat treatment by laser; a phase of modifying the roughness of the material containing the epilame product, in particular a laser treatment phase.

According to one embodiment of the invention, the deposition of the epilame product is carried out in the form of a projection onto the substrate of a localized bead of material containing the epilame product, said bead being a continuous or discontinuous bead.

[0022] Advantageously, the localized bead of material has a width of at least 10 μm, preferably at least 15 μm.

According to another embodiment of the invention, the deposition of the epilame product is carried out in the form of a projection onto the substrate of two collimated or localized beams of liquid material, at least one of the liquid materials containing the epilame product , the two liquid materials projected by the beams being chosen so as to cause solidification when brought into contact with each other.

According to a first variant embodiment of the invention, during the deposition step, the projection onto the substrate of at least one collimated or localized beam of material containing the epilame product is carried out by means of at least a fixed projection nozzle, the or each projection nozzle being configured to project substantially vertically, from top to bottom, a collimated or localized beam of material; the orientation and/or the position in space of the substrate being modified during the deposition step. Such a configuration, implementing a vertical projection of material from top to bottom, improves the precision of the deposition of epilame product, which makes it possible to guarantee that the deposition is carried out at the precise location desired on the part.

According to a second alternative embodiment of the invention, during the deposition step, the projection onto the substrate of at least one collimated or localized beam of material containing the epilame product is carried out by means of at least a projection nozzle mounted movable relative to the substrate, for example mounted on a multi-axis robot; the substrate being kept fixed during the deposition step.

According to a particular technical characteristic of the invention, the second material consists of a single component, in particular a polymer, more particularly an epoxy resin. The polymer is typically a photocurable polymer or a thermosetting polymer.

Alternatively, the second material comprises several components. Each of the components is typically in liquid or solid form.

According to a particular technical characteristic of the invention, each of the components is chosen from the group of components consisting of: a surfactant component; a solvent; a component having a physical, chemical or mechanical repulsion function; a component having an aesthetic function; a component having a function intended to promote crosslinking; or a combination thereof.

[0029] To this end, the invention also relates to an epilamé mechanical part obtained by the manufacturing method described above, and which comprises the characteristics mentioned in dependent claim 17.

[0030] A particular form of the epilamé mechanical part is defined in dependent claim 18.

[0031] According to a particular technical characteristic of the invention, the epilamé mechanical part is a part for watchmaking.

BRIEF DESCRIPTION OF FIGURES

The aims, advantages and characteristics of the process for manufacturing an epilamé mechanical part according to the invention will appear better in the following description on the basis of at least one non-limiting embodiment illustrated by the drawings in which: FIG. 1 is a flowchart representing the steps of a method of manufacturing an epilamé mechanical part according to the invention; FIG. 2 is a schematic view of a system for implementing the method of FIG. 1, according to a first embodiment of the invention; Figure 3 is a view similar to that of Figure 2, according to a second embodiment of the invention; and FIG. 4 is a perspective view of an epilamé mechanical part obtained by the method of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows a method of manufacturing an epilamé mechanical part 2 according to the invention. Such an epilame mechanical part 2, which is visible in FIGS. 2 to 4, comprises a substrate 4. This substrate 4 is the support on which the epilame product 6 will be deposited. The epilamé mechanical part 2 can be a part for watchmaking, such as for example a plate, an anchor lifter, a wheel, a pendulum or even an axle. Part 2 can also be a part of an object using mechanical or micromechanical components in relative motion and whose contacts are lubricated with a fluid lubricant which can migrate and thus alter the tribological function. Of course, the method of manufacturing such an epilame mechanical part 2 according to the invention can be suitable for all applications using an epilame.

Returning to Figure 1, the method comprises an initial step 10 of depositing the epilame product 6 on the substrate 4. The substrate 4 consists of a first material, and the epilame product 6 consists of a second material, distinct from the first material. The first material can consist, for example, of metal, ceramic, ruby, sapphire, plastic, diamond, quartz, glass, silicon carbide, amorphous materials (eg: metallic glasses) or a combination thereof. The second material can consist of a single component, such as for example a polymer. The polymer is typically a photocurable or thermosetting polymer, such as for example an epoxy resin. Alternatively, the second material comprises several components. Each of the components is for example in liquid or solid form. The components can be chosen in particular so that their functions are complementary in order, for example, to promote cross-linking, to facilitate the location of the material, to provide a function specific to the repulsion of the lubricant, to provide an aesthetic function, for example linked to the color or texture, bring roughness to the deposited material, or even carry out the transport of the useful component(s) to the final function. As such, the components can be selected from the group of components consisting of: a surfactant component; a solvent; a component having a physical, chemical or mechanical repulsion function; a component having an aesthetic function; or else a component having a function intended to promote crosslinking. A component chosen as a solvent can make it possible to facilitate the transport of the other component(s) useful for the final function. A component chosen to give visible pigmentation to the epilame product 6 can make it possible to visually facilitate the operations carried out by an operator, for example by conferring a coloring on the lubricant.

The method comprises a following step 11 of processing the second material constituting the epilame product 6 to ensure the cohesion of the components on the substrate 4 of the part 2.

The deposition step 10 is performed in the form of a projection onto the substrate 4 of at least one collimated or localized beam 12, 12A, 12B of material containing the epilame product 6. According to a first embodiment of the invention, illustrated in FIG. 2, the deposition is carried out in the form of a projection onto the substrate 4 of a single beam 12 containing the epilame product 6. The beam 12 is for example configured to project onto the substrate 4 a continuous and localized cord 14 of material containing the epilame product 6. The continuous cord 14 typically has a width of at least 10 μm, preferably at least 15 μm. It will be noted that the maximum width of the bead depends on the geometry of the part and the desired aesthetics. In the extreme, it is thus possible to completely cover the room except for the only functional area. In a variant not shown, the beam 12 is configured to project onto the substrate 4 a discontinuous and localized bead of material containing the epilame product, for example in the form of a discontinuous series of patterns such as dots or lines.

Note that the cord must be closed if you want it to be confined. By way of example, the beam 12 is configured to project a closed bead of material containing the epilame product onto a substrate 4 on which are drawn migration paths through which the lubricant would move in a controlled manner. This makes it possible to deposit the lubricant in an easily accessible zone from which it migrates towards the targeted functional zone but less easy to access.

According to a second embodiment of the invention, illustrated in Figure 3, the deposition is performed in the form of a projection on the substrate 4 of two beams 12A, 12B collimated or localized liquid material. At least one of the liquid materials contains the epilame product 6. In the particular embodiment of FIG. 3, only the liquid material projected by the first nozzle 16A contains the epilame product 6. The two liquid materials projected by the beams 12A, 12B are chosen so as to cause solidification when brought into contact with each other. This is the principle of the Araldite™ two-component adhesive, made up of an epoxy resin and a polymerizing agent, 1,4,7,10-tetraazadecane. In contact with these two components, a polyepoxide is formed.

Preferably, and as illustrated in the two embodiments of Figures 2 and 3, the projection on the substrate 4 of at least one collimated or localized beam 12, 12A, 12B of material containing the epilame product 6 is carried out by means of at least one fixed spray nozzle 16, 16A, 16B. To do this, a system 18 is used, which comprises, in addition to the nozzle(s) 16, 16A, 16B, a device 20 for controlling the jet projected by the latter. The mechanical part 2 on which the epilame product 6 is deposited is arranged under the or each nozzle 16, 16A, 16B, directly above it(s). In the first embodiment illustrated in Figure 2, the system 18 includes a single fixed blast nozzle 16. In the second embodiment illustrated in Figure 3, the system 18 includes two fixed blast nozzles 16A, 16B, each nozzles 16A, 16B projecting one of the collimated or localized beams 12A, 12B of liquid material. In both cases, the or each fixed projection nozzle 16, 16A, 16B is configured to project substantially vertically, from top to bottom, a corresponding beam 12, 12A, 12B of material. The orientation and/or the position in space of the mechanical part 2, and therefore of the substrate 4 on which the epilame product 6 is deposited, are modified during the deposition step 10. To do this, the system 18 comprises for example a device 22 for multi-axis positioning of the part 2, connected to the control device 20. This makes it possible to precisely adjust the orientation and/or the position in space of the mechanical part 2, via the control 20. Such a configuration improves the precision of the deposition of epilame product 6, which makes it possible to guarantee that the deposition is carried out at the precise location desired on the mechanical part 2.

In a variant not shown, the multi-axis positioning device 22 is used to impart mobility in space to the or each spray nozzle. The mechanical part 2, and therefore the substrate 4 on which the epilame product 6 is deposited, are then kept fixed during the deposition step 10, by any known means. The positioning device is for example a multi-axis robot, making it possible to modify the orientation and/or the position in space of the or each nozzle according to the three dimensions of space, the or each nozzle then moving around the piece 2.

Preferably, and although this is not limiting in the context of the present invention, the deposition step 10 comprises a phase 24 of nebulization of an ink containing the epilame product 6 in the form of a solution or suspension. of particles, and a phase 26 for spraying the nebulized ink onto the substrate 4 of the part 2. In this case, the or each spray nozzle 16, 16A, 16B is connected to a spray chamber, such a chamber n not being shown in the figures for reasons of clarity. The nebulization phase 24 then takes place in the nebulization chamber, the projection phase 26 being carried out by the nozzle(s) 16, 16A, 16B, if necessary controlled by the control device 20. The particles are typically micrometric, submicron, or even nanometric particles, which have an active function of the type of those detailed above. Of course, other variant embodiments are possible for the deposition step 10 without departing from the scope of the present invention. It will be noted that this deposition step described here is based on the AJP technology, acronym for "Aerosol Jet Printing". However, it is possible to deposit a material by other technologies, such as for example digital printing, the spitting of drops which close together form a bead, etc. It is therefore understood that this deposition step is therefore not limited solely to this AJP technology.

When the deposition step 10 comprises a phase 24 of nebulizing an ink and a phase 26 of spraying the nebulized ink onto the substrate 4, the processing step 11 preferably comprises when the ink requires a phase 28 of hardening of the second material. By „hardening“ we mean the process of directly or indirectly binding the particles to obtain their cohesion. It will be noted that certain inks do not require a hardening step, for example by crosslinking strictly speaking. A brief moment in the open air is enough for the solvent to evaporate and the resin to crosslink „all by itself“.

The hardening phase 28 consists for example of a heat treatment of the second material, which comprises at least one annealing step and/or a localized sintering step and/or a vacuum step. This is notably the case when the second material consists of a thermosetting polymer. Such a heat treatment makes it possible to accelerate the solidification process. The localized sintering is for example carried out by irradiating the second material by means of a laser, such as an infrared laser for example. Such a hardening phase can also comprise, before the actual heat treatment, a natural drying step, typically in the case of a suspension of particles in a volatile solvent.

As a variant, the hardening phase 28 can consist of an artificial hardening obtained via polymerization by photo-crosslinking and/or by chemical cross-linking. This is notably the case when the second material consists of a photohardenable polymer. Polymerization by photo-crosslinking is typically obtained by the projection of ultraviolet rays onto the material containing the epilame product 6, at a predetermined wavelength.

As a further variant, and more generally, step 11 for processing the second material comprises at least one of the following phases: a phase of modifying the chemical structure of the material containing the epilame product 6, in particular an ion implantation phase; a phase of modification of the crystallographic structure of the material containing the epilame product 6, in particular a phase of localized heat treatment by laser; and or a phase of modifying the roughness of the material containing the epilame product 6, in particular a laser treatment phase.

Claims (18)

1. Method for manufacturing an epilamé mechanical part (2) comprising a substrate (4) in a first material, the method comprising at least: – a step (10) of local deposition on the substrate (4) of an epilame product (6) consisting of a second material, said deposition being carried out in the form of a projection on the substrate (4) of at least a bundle (12; 12A, 12B) of material containing the epilame product (6); and – a step (11) of processing the second material comprising at least one component to ensure the cohesion of said at least one component on the substrate (4). 2. Manufacturing process according to claim 1, characterized in that the deposition step (10) comprises a phase (24) of nebulization of an ink containing the epilame product (6) in the form of a solution or suspension of particles , and a phase (26) for spraying the nebulized ink onto the substrate (4) of the part (2); and in that the step (11) of treating the second material comprises a phase (28) of hardening said second material. 3. Manufacturing process according to claim 2, characterized in that the hardening phase (28) consists of a heat treatment which comprises at least an annealing step and / or a localized sintering step and / or a step of placing under empty. 4. Manufacturing process according to claim 3, characterized in that the localized sintering step is obtained by irradiating said second material by means of a laser. 5. Manufacturing process according to claim 2, characterized in that the curing phase (28) consists of polymerization by photo-crosslinking and/or by chemical cross-linking. 6. Manufacturing process according to claim 5, characterized in that the polymerization phase by photo-crosslinking is obtained by the projection of ultraviolet rays onto the material containing the epilame product (6), at a predetermined wavelength. 7. Manufacturing process according to one of the preceding claims, characterized in that the step (11) of processing said second material comprises at least one of the following phases: – a phase of modifying the chemical structure of the material containing the epilame product (6), in particular an ion implantation phase; – a phase of modification of the crystallographic structure of the material containing the epilame product (6), in particular a phase of localized heat treatment by laser; – a phase of modifying the roughness of the material containing the epilame product (6), in particular a laser treatment phase. 8. Manufacturing process according to one of the preceding claims, characterized in that the local deposition of the epilame product (6) is carried out in the form of a projection on the substrate (4) of a localized bead (14) of the material containing the epilame product (6), said bead (14) being a continuous or discontinuous bead. 9. Manufacturing process according to claim 8, characterized in that the localized bead (14) of material has a width of at least 10 μm, preferably at least 15 μm. 10. Manufacturing process according to one of the preceding claims, characterized in that the deposition of the epilame product (6) is carried out in the form of a projection on the substrate (4) of two beams (12A, 12B) collimated or localized of liquid material, at least one of the liquid materials containing the epilame product (6), the two liquid materials projected by the beams (12A, 12B) being chosen so as to cause solidification when brought into contact with each other . 11. Manufacturing process according to one of the preceding claims, characterized in that, during the deposition step (10), the projection onto the substrate (4) of at least one beam (12; 12A, 12B ) collimated or localized material containing the epilame product (6) is carried out by means of at least one fixed spray nozzle (16; 16A, 16B), the or each spray nozzle (16; 16A, 16B) being configured to projecting substantially vertically, from top to bottom, the collimated or localized beam (12; 12A, 12B) of material; the orientation and/or the position in space of the substrate (4) being modified during the deposition step (10). 12. Manufacturing process according to any one of claims 1 to 10, characterized in that, during the deposition step (10), the projection onto the substrate (4) of at least one beam (12); 12A, 12B) collimated or localized material containing the epilame product (6) is carried out by means of at least one projection nozzle mounted movable relative to the substrate (4), for example mounted on a multi-axis robot; the substrate (4) being kept fixed during the deposition step (10). 13. Manufacturing process according to one of the preceding claims, characterized in that the second material consists of a single component, in particular a polymer, more particularly an epoxy resin. 14. Manufacturing process according to one of claims 1 to 12, characterized in that the second material comprises several components. 15. Manufacturing process according to claim 14, characterized in that each of the components is in liquid or solid form. 16. Manufacturing process according to claim 14 or 15, characterized in that each of the components is chosen from the group of components consisting of: a surfactant component; a solvent; a component having a physical, chemical or mechanical repulsion function; a component having an aesthetic function; a component having a function intended to promote crosslinking; or a combination thereof. 17. Epilated mechanical part (2) obtained according to the method according to one of claims 1 to 16. 18. Mechanical part (2) according to claim 17, characterized in that the epilamé mechanical part (2) is a part for watchmaking.