CH717123B1 - Metal marking process for a watch component. - Google Patents

Abstract

The present invention relates to a method for marking a watch component by means of an incident laser beam (6), of the nanosecond or femtosecond type, arranged to pass through at least a portion (2) of the watch component having first and second faces (18, 20) opposed and made of a transparent material, the method comprising the steps consisting in: arranging the portion (2) so that the incident laser beam (6) has an angle of incidence on the first face (18) substantially between 0 and 60 degrees, and in such a way that the portion (2) and the incident laser beam (6) can be moved relative to each other, positioning a metal substrate (22) close to the second face (20), and controlling the incident laser beam (6) so that it has a focal plane located on the surface of the metal substrate (22), to give rise to a transfer of matter from the latter to the portion (2).

Description

Technical area

The present invention relates to a method for marking a watch component by means of a first laser source arranged, in conjunction with an optical device, to define an incident laser beam intended to mark the watch component.

State of the art

[0002] Numerous processes for processing watch components by laser beam are already known from the state of the art.

[0003] Thus, for example, patent application EP 2825347 A1 describes such a process for machining a watch component, more particularly for engraving it by means of a laser beam, the properties of which simultaneously make it possible to change the coloring of the component. in the path of the laser beam.

[0004] Even if the process described in this prior art patent application is also applicable to materials such as sapphire, processes of this type are mainly intended for treating metal watch components.

[0005] In general, most of the applications relating to the processing of watch components by laser beam essentially aim to cut or engrave the material constituting all or part of the watch component.

Disclosure of Invention

[0006] A main object of the present invention is to propose an alternative method to the methods of treatment of watchmaking components by laser beam known from the prior art, the method according to the invention allowing the production of an original marking by laser beam on a watch component, and therefore the customization of the latter with a high perceived quality.

To this end, the present invention relates more particularly to a method for marking a watch component of the type mentioned above, characterized in that the incident laser beam is arranged to pass through at least a portion of the watch component, this portion having first and second opposite faces and being made of a material at least partially transparent to the incident laser beam, the method comprising the steps consisting in: arranging the first face of the portion of the timepiece component relative to the incident laser beam in such a way that the incident laser beam has an angle of incidence on the first face substantially between 0 and 60 degrees, and such that the portion of the timepiece component and the incident laser beam can be moved relative to each other, positioning a metallic substrate close to the second face of the portion of the watch component, controlling the first laser source in such a way that the incident laser beam is composed of light pulses whose duration is of the order of magnitude of a nanosecond or femtosecond, and having a focal plane located substantially on the surface of the metal substrate, so as to give rise to a transfer of material from the metal substrate to the second face of the portion of the watch component, and to move the incident laser beam and the portion of the timepiece component relative to each other to produce a metallic marking on the second face of the portion of the timepiece component.

[0008] The portion to be processed can directly be a watch component as such or only a portion of a watch component, either made in one piece with the rest of the component, or attached to the rest of the component before or after the implementation of the method according to the invention, without departing from the scope of the latter.

[0009] Thanks to these characteristics, it is possible to produce a distinctive metallic marking on a watch component, at least a portion of which is at least partially transparent to the wavelength of the laser source used. The method according to the invention makes it possible to produce such a metallic marking with very precise control, therefore with good reproducibility and excellent resolution of the order of a few micrometers. The metallic marking can have the form of a continuous or discontinuous extended pattern, that is to say having portions separated from each other. It should also be noted that the method according to the present invention can be implemented without it being necessary to provide a protected enclosure during the laser treatment, in particular a vacuum enclosure, which is particularly advantageous from the point of view of handling of watch components to be treated.

[0010] In general, the method according to the invention may comprise an additional step consisting in treating the metallic marking by means of a reprocessing laser beam defined from the first laser source or from a second laser source , such that the reprocessing laser beam is composed of light pulses whose duration is of the order of magnitude of a nanosecond and such that the reprocessing laser beam is emitted in the direction of the second face, so at least partially sweeping away the metal marking.

[0011] More precisely, the properties of the reprocessing laser beam can be adjusted in such a way that its effect on the metallic marking gives the latter a metallic luster, or even a predefined coloration, possibly different from that of the starting metallic substrate.

[0012] It is thus possible to obtain a high level of customization of the watch component treated by the method according to the invention.

[0013] In general, provision can be made for the incident laser beam to be composed of pulses having an average frequency of between 100 and 250 kHz and, preferably, for it to have an average power of less than 20 Watts, more preferably less than 15 Watts, even more preferably less than 10 Watts.

[0014] In general, the portion of the watch component on which the metal marking is made can advantageously comprise glass or sapphire and, preferably, have a thickness, between its first and second faces, substantially between 0.1 and 3 mm, more preferably between 0.4 and 2.5 mm.

[0015] According to a preferred embodiment, provision may be made for the metallic substrate to comprise one or more of the materials taken from the group comprising: steels, stainless steels, titanium, copper, brass, gold, platinum, tungsten.

[0016] In general, provision can be made for the metal marking to have a thickness substantially between 1 and 5 micrometers.

[0017] Advantageously, provision can be made for the metallic substrate to be positioned at a maximum distance from the second face of the order of 500 micrometers, preferably of the order of 300 micrometers, during the implementation of the transfer of material from the metal substrate to the portion to be treated of the watch component.

The present invention also relates to a timepiece component having a metal marking obtained by implementing the method which has just been presented, as well as a timepiece comprising such a timepiece component.

Brief description of the drawings

Other characteristics and advantages of the present invention will appear more clearly on reading the detailed description of a preferred embodiment which follows, made with reference to the accompanying drawings given by way of non-limiting example and in which : - figure 1 represents a simplified block diagram of an example of implementation of a first step of a method for processing a watch component according to a preferred embodiment of the present invention, and - figure 2 represents a simplified block diagram of an example of implementation of an additional step of the processing method of FIG. 1.

Embodiment(s) of the Invention

[0020] FIG. 1 represents a simplified block diagram of an example of implementation of a first step of a method for processing a watch component according to a preferred embodiment of the present invention.

More specifically, the laser beam marking method according to the present invention aims to mark a portion 2 of a watch component (not shown in its entirety), this portion 2 being advantageously at least partially transparent to the length of wave of the laser beam used to carry out the marking. Thus, in general, it will be possible to implement the method according to the invention in relation to all kinds of materials that are at least partially transparent in the field of visible light, such as glass or sapphire, by way of non-limiting illustration.

[0022] Portion 2 can directly be a watch component as such or only a portion of a watch component, either made in one piece with the rest of the component, or attached to the rest of the component, without departing from the frame. of the invention. It is conceivable to use portion 2 for authentication purposes of the timepiece in which the timepiece component is assembled.

[0023] Furthermore, provision may be made for the timepiece component to be directly visible on the corresponding timepiece, being located outside the box or inside but being visible through a glass, or it may be housed inside the box and only be at least partially visible once the latter has been opened. Alternatively, it is also possible to provide for the timepiece component comprising the marking according to the invention to be visible only after dismantling one or more other components of the corresponding timepiece, without departing from the scope of the invention.

In general, to carry out the marking according to the invention, a first laser source 4 is used arranged, in connection with an optical device, to define an incident laser beam 6 intended to carry out the marking on the portion 2 of the component. watchmaker.

More specifically, the optical device may comprise, by way of non-limiting illustration, at least one first mirror 8 arranged at the output of the first laser source 4, the latter typically being able to be associated with a galvanometric head 10 comprising a set of mirrors additional, here schematized in the form of two mirrors 12 and 14, making it possible to control the direction of propagation of the incident laser beam 6 and to cause the latter to be scanned in order to carry out the marking on the portion 2, according to the invention. The optical device also comprises, advantageously, a focusing device 16, schematized here in the form of a converging lens to define a desired focusing plane for the incident laser beam 6.

Advantageously, the first laser source 4 can be associated with the optical device directly inside a multi-axis CNC machine.

The portion 2 of the watch component is shown here in the form of a parallelepiped having first and second main faces 18 and 20, the first 18 of which is positioned so as to be arranged on the path of the incident laser beam 6.

The portion 2 of the watch component is arranged relative to the incident laser beam 6 in such a way that the latter has an angle of incidence on its first face 18 substantially between 0 and 60 degrees, and in such a way that the portion 2 and the incident laser beam 6 can be moved relative to each other.

Thus, when a numerically controlled machine is used, it is advantageously programmed to control the incident laser beam 6 and its movements appropriately to carry out a marking of the portion 2 along a predefined path. The numerically controlled machine typically comprises a control device, for this purpose, taking into account the geometry of the portion 2 and of the marking to be produced, and defining the scanning speed of the surface to be treated by the incident laser beam 6 as well as the amplitude of movement of the beam and the generation of laser pulses, so as to obtain the desired marking. Advantageously, all of the marking of portion 2 can be carried out in a single operation.

Preferably, the portion 2 has a thickness, between its first and second faces 18 and 20, substantially between 0.1 and 3 mm, preferably between 0.4 and 2.5 mm.

A metal substrate 22 is positioned in the immediate vicinity of the second face 20 of portion 2, that is to say after portion 2 following the optical path of the incident laser beam 6.

[0032] Preferably but not limitingly, the metal substrate 22 comprises one or more of the materials taken from the group comprising: steels, stainless steels, titanium, copper, brass, gold, platinum, tungsten.

Furthermore, the metal substrate 22 is preferably positioned at a maximum distance from the second face 20 of the order of 500 micrometers, preferably of the order of 300 micrometers.

Advantageously, the first laser source is chosen such that it defines an incident laser beam 6 composed of light pulses whose duration is of the order of magnitude of a nanosecond or a femtosecond. In addition, the optical device is preferably arranged in such a way that the incident laser beam 6 has a focal plane located substantially at the surface of the metal substrate 22, so as to give rise to a transfer of material from the metal substrate 22 to the second face 20 of portion 2 of the timepiece component.

[0035] Typically, to treat metal substrates such as those mentioned above, a first laser source 4 may be chosen such that the incident laser beam 6 is composed of pulses having an average frequency of between 100 and 250 kHz, and such that the latter has an average power of less than 20 Watts, preferably less than 15 Watts, even more preferably less than 10 Watts.

The number of pulses to be applied per mm<2> to produce a metallic marking according to the invention depends in particular on the energy fluence of the laser beam used, its frequency, the scanning distance and the scanning speed. . Typically, creating a basic pattern on a watch component may require 10<4>to 10<6>pulses per mm<2>, i.e. 10<6>to 10<8>pulses for a 1 cm pattern <2>.

Thus, by the implementation of the above characteristics, it is possible to produce a metallic marking having a thickness substantially between 1 and 5 micrometers.

[0038] Typically, the metallic marking thus obtained has a dark, generally black colour.

Also, advantageously, there is provided an additional surface treatment step by laser of the metal marking produced according to the preceding description, as shown schematically in Figure 2. More specifically, it can preferably be provided that this additional treatment step metallic marking makes it possible to modify its micro-structuring, at least on the surface, in particular so that it has at least one metallic luster, or even so that its coloring is modified so as to present a new predefined coloring.

To produce such colorations of the metallic marking, it is subjected to the action of a laser with a short or ultra-short pulse duration, preferably a laser source 24 of the nanosecond type defining, in association with a optical device not shown, a reprocessing laser beam 26, acting as a heat source which reacts with the oxygen of the environment to coat the treated surface with a layer of transparent or semi-transparent oxide. Depending on the parameters of the reprocessing laser beam 26 such as its power, its frequency, its pulse width, the scanning speed, the chopping frequency, the number of repetitions or the distance between the treated surface and the focal plane of the reprocessing laser beam 26, among other things, the oxide layer will have a certain thickness. By then illuminating the metallic marking with white light, the radiation is reflected by the upper and lower oxide layers. Consequently, a phenomenon of interference of the reflected rays is perceived by an observer as corresponding to a given color.

When the first laser source 4 used is a source of the nanosecond type, this same laser source 4 can again be used to implement the additional step. When the first laser source 4 is of the femtosecond type, another laser source 24 of the nanosecond type should be used to implement the additional step.

[0042] In all cases, it is preferable to move the watch component between the production of the metal marking and the implementation of the additional step, so that the second face 20 of the portion 2 is directly exposed to the beam reprocessing laser 26 of the metal marking aimed at improving the appearance of the latter. Thus, the reprocessing laser beam 26 must be emitted in the direction of the second face 20 of the portion 2 of the watch component, so as to scan at least partially the metal marking, so that the appearance of at least part of this last be modified.

The implementation of the present invention is not limited to a timepiece component forming part of the casing of a timepiece. Indeed, any timepiece component can allow the implementation of the present invention, whether to confer a distinctive character on the timepiece component and therefore on the corresponding timepiece, or whether for identification purposes or authentication. A person skilled in the art will not encounter any particular difficulty in adapting the present teaching to the manufacture of watch components for coverings or of the watch movement. It may even be envisaged that the portion 2 of the timepiece component is only visible after disassembly of the timepiece component to increase the level of security in the identification or authentication of the corresponding timepiece.

The foregoing description sets out to describe a particular embodiment by way of non-limiting illustration and, the invention is not limited to the implementation of certain particular characteristics which have just been described, such as the nature of the watch component or the material in which it is made.

Claims (13)

1. Method for marking a watch component by means of a first laser source (4) arranged, in conjunction with an optical device, to define an incident laser beam (6) intended to produce a marking on said watch component, characterized in that said incident laser beam (6) is arranged to pass through at least one portion (2) of said timepiece component, said portion (2) having first and second opposite faces (18, 20) and being made of a material at least partially transparent for said incident laser beam (6), the method comprising the steps of: arranging said first face (18) of the portion (2) of the timepiece component relative to said incident laser beam (6) in such a way that said incident laser beam (6) has an angle of incidence on said first face (18) substantially comprised between 0 and 60 degrees, and in such a way that said portion (2) and said incident laser beam (6) can be moved relative to each other, positioning a metal substrate (22) close to said second face (20) of the portion (2) of the timepiece component, controlling said first laser source (4) in such a way that said incident laser beam (6) is composed of light pulses whose duration is of the order of magnitude of a nanosecond or a femtosecond, and having a focal plane located substantially on the surface of said metal substrate (22), so as to give rise to a transfer of material from said metal substrate (22) to said second face (20) of the portion (2) of the timepiece component, and moving said incident laser beam (6) and said portion (2) of the timepiece component relative to each other to produce a metallic marking on said second face (20) of the portion (2) of the timepiece component. 2. Method according to claim 1, characterized in that it comprises an additional step consisting in treating said metallic marking by means of a reprocessing laser beam (26) defined from said first laser source (4) or from a second laser source (24), such that said reprocessing laser beam (26) is composed of light pulses whose duration is of the order of magnitude of a nanosecond and such that said laser beam of reprocessing (26) is emitted in the direction of said second face (20), so as to scan at least partially said metallic marking. 3. Method according to claim 2, characterized in that the properties of said reprocessing laser beam (26) are adjusted in such a way that its effect on said metallic marking gives the latter a metallic luster. 4. Method according to claim 2 or 3, characterized in that the properties of said reprocessing laser beam (26) are adjusted in such a way that its effect on said metallic marking gives the latter a predefined coloration. 5. Method according to one of the preceding claims, characterized in that said incident laser beam (6) is composed of pulses having an average frequency of between 100 and 250 kHz. 6. Method according to one of the preceding claims, characterized in that said incident laser beam (6) has an average power of less than 20 Watts, preferably less than 15 Watts, even more preferably less than 10 Watts. 7. Method according to one of the preceding claims, characterized in that the portion (2) of said timepiece component on which said metallic marking is made comprises glass or sapphire. 8. Method according to one of the preceding claims, characterized in that the portion (2) of said timepiece component on which said metallic marking is made has a thickness, between said first and second faces (18, 20), substantially between 0.1 and 3 mm, preferably between 0.4 and 2.5 mm. 9. Method according to one of the preceding claims, characterized in that said metal substrate (22) comprises one or more of the materials taken from the group comprising: steels, stainless steels, titanium, copper, brass, gold, platinum, tungsten. 10. Method according to one of the preceding claims, characterized in that said metallic marking has a thickness substantially between 1 and 5 micrometers. 11. Method according to one of the preceding claims, characterized in that said metal substrate (22) is positioned at a maximum distance from said second face (20) of the order of 500 micrometers, preferably of the order of 300 micrometers , during the implementation of said material transfer from said metal substrate (22) to said portion (2) of said timepiece component. 12. Watch component comprising a metal marking produced by the implementation of a marking method according to one of claims 1 to 11. 13. Timepiece comprising a timepiece component comprising a metal marking produced by the implementation of a marking method according to one of claims 1 to 11.