Patent Application
20210356912
The present invention relates to a method for manufacturing timepiece components, and more particularly varnished appliques intended to be attached on the dial of a timepiece by means of fixing feet in order to replace all or part of the numerals indicating the hours. Such a method may also be used for the production of dials or bezels.
Appliques disposed on the hour-circle, or on secondary dials, are most often produced by tracing, or even by silkscreen by giving the impression of having been printed. Timepiece appliques are essential elements of a timepiece, in particular of a watch, by contributing to giving it a particular physiognomy. Consequently, their execution must be particularly meticulous, highly reproducible, and devoid of any surface condition defect. A perfect execution is made difficult by the very small size of these appearance components, and by their difficult gripping. Consequently the reject rate may be high. This manufacturing is even more tricky when the appliques have a coating such as varnish or lacquer, in order to obtain a particular aesthetic effect. In the case of varnished appliques, it is known to deposit the applique on a support and apply a varnish layer thereto. It is understood that, in this case, varnish is deposited both on the applique and on the support. A join then forms between the applique and the support by capillary action, the appearance is then poor which is unacceptable.
One aim of the present invention is to overcome all or part of the previously mentioned drawbacks by providing a method for manufacturing high-quality timepiece appliques by ensuring a perfect surface condition of the visible portions.
To this end, the invention relates to a method for manufacturing appliques that comprises the following steps according to which:
In accordance with other advantageous variants of the invention:
Thanks to these features, such a method for manufacturing a timepiece applique makes it possible to obtain appliques rapidly whilst having a perfect surface condition of the visible parts.
Other features and advantages of the invention will become more apparent upon reading the following description of a particular embodiment of the invention, given by way of simple illustrative and non-limiting example, and the appended figures, wherein:
The invention relates to a method for manufacturing a timepiece applique 1.
“Applique” means any display or decoration element intended to be seen by a user, such as a sign, index, numeral, logo, monogram, or similar, placed on an object, particularly a dial, a collar, a plate, a bridge, or similar.
Such an applique 1 usually includes an upper surface 2 and a rim 3 intended to be seen by a user, a lower surface 4 for its resting on a dial or a structure of a timepiece.
If this lower surface 4 can be glued directly on such a dial or such a structure, it generally includes at least one foot 5. Each foot 5 is protruding from this lower surface 4, and more particularly but not limited to according to a particular orientation in the space in relation to the lower surface 4, for its fastening on such a dial or such a structure.
According to the invention, for the manufacturing of such an applique 1, the following steps are performed successively:
The machining of the upper surface 2 and of the rim 3 by a CNC machine for producing the upper surface 2 and the rim 3, may be, depending on the case, performed on a single tool, or even on a plurality of tools, each specific to an operation for machining a particular surface. The machining may obviously implement various technologies, combined or not, and not limited to: milling, grinding, electroerosion, laser, or other.
Naturally the upper surface 2 and the rim 3 of the applique 1 may be more or less complex, and include for example a plurality of elementary surfaces such as flat facets, or other. According to the complexity of the upper surface, the machining and/or the diamond polishing of the upper surface 2 is performed with a machining and/or diamond polishing unit moveable along at least 5 axes in relation to the base.
The base 10 is produced from a metal material or metal alloy such as brass, aluminium or a precious metal. The base 10 is also used as support for the applique 1 during the manufacturing process until the lower surface 4 and the foot 5 are machined.
According to a particular feature of the invention, the machining of the upper surface 2 and of the rim 3 of the applique 1 in the base 10 is carried out from the upper face of the latter, the machining having a predefined depth P. Advantageously, the depth P of the machining is provided greater than the final height H of the applique 1.
According to a particular feature of the invention, after the production of the upper surface 2 and of the rim 3, the machined base 10 is washed via ultrasound washing, such as to eliminate all of the dust and residues related to the machining and to prevent any defect in the varnish layer.
More particularly, according to a particular feature of the invention, a buffing of the upper surface 2 and of the rim 3 of the applique 1 machined in the base 10 is carried out so as to polish the edges of the applique and improve the covering power of the varnish.
A new washing step is carried out after the buffing, the base is then washed by way of electrolytic leaching.
According to one variant of the invention, the base may receive a surface treatment in order to promote the resistance of the varnish layer, such a treatment may consist of a sanding or plasma operation for example. A new washing step may then be necessary in order to eliminate the impurities present.
According to a particular feature of the invention, a varnish layer 13 is deposited on the machined upper face of the base 10 so as to cover the upper face of the base, and implicitly the upper surface 2 and the rim 3 of the applique 1. The varnish layer is deposited by way of a spraying operation, a hardening of the base may also be carried out. The varnish layer has a sufficient thickness for covering the applique, typically the thickness is between 20 μm and 100 μm.
Then, this varnish layer 13 is dried in a stove at 80° C. for 30 min, then at 140° C. for 60 min. Two-step drying makes it possible to obtain a slow and regular polymerisation and thus a better homogeneity of the thickness of the varnish. Obviously, the parameters of this drying step may be varied according to the specificities requested by the manufacturer.
According to a particular feature of the invention, a glue layer 14 is deposited on the upper face of the base 10, the glue layer 14 then being superimposed on the varnish layer 13 and envelopes the upper surface 2 and the rim 3 of the applique 1. Advantageously, the glue layer 14 is deposited over at least the entire depth of the machining, or even slightly more so as to exceed the plane formed by the upper face of the base. Preferably, a water-base glue of Prolaq® type is used to prevent damaging the varnish during the dissolution of the glue in a subsequent step.
The following step consists of drying the glue layer 14 deposited, for this the base coated with glue is placed in a stove at 45° C. for at least 5 hours.
Once the glue layer 14 has dried, an optional levelling step is carried out. The glue layer is machined by way of surfacing for example, so as to obtain a uniform layer, to accelerate the release of the applique at the end of the method, and to form a flat reference surface for the dimensional during the machining of the lower face
According to a particular feature of the invention, the lower surface 4 and the foot 5 of the applique 1 are machined via the lower face 12 of the base 10. This machining is carried out over a depth P′ greater than the thickness E of the base 10 less the machined depth P of the upper face, namely P′>(E−P).
The machining of the applique 1 via the lower face of the base is carried out at dimensions slightly greater than the rim 3 of the applique 1 so as to separate the applique from the base, the applique thus formed no longer being connected to the base 10 and then only being held by the glue layer 14 deposited previously.
According to a particular feature of the invention, the base is plunged into an aqueous solution in order to dissolve the glue and release the applique from the glue layer. The bath of the base 10 in the solution is performed in a basket in order to be able to easily recover the released applique.
In the case described here, the liquid solution used is an alkaline aqueous solution in order to dissolve the glue, the base 10 being plunged into a succession of leaching baths at 55° C. for 60 min so as to ensure a good dissolution of the glue. Obviously other liquid solutions may be used depending on the glue chosen, just like the leaching time and the temperature of the aqueous solution may vary depending on the glue used.
Lastly the applique may be washed once again in order to remove any glue residues, then dried. The applique may also receive other decorative treatments such as the deposition of a luminescent material.
Finally, the applique is packaged on a storage pallet in view of its delivery.
The invention also relates to a watch comprising at least one applique 1
Of course, the present invention is not limited to the example illustrated and is susceptible to various variants and modifications that will become apparent to the person skilled in the art.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20175197.1 | May 2020 | EP | regional |
