The invention relates to a method of fabricating a micro-mechanical component and, more specifically, a method of this type for assembling micro-machined and/or electroformed components.
It is advantageous in the watchmaking industry to fabricate components or parts of components by using a micro-machining process, for example photolithography then deep reactive ion etching, or electroplating, for example photolithography then galvanic growth. These processes make fabrication with improved precision possible, compared to conventional techniques.
However, it is difficult to form components from several parts. Thus, in the case of electroformed components, a laser weld between two parts and, for example, an arbour, is liable to deform the parts and arbour so that the very high level of precision resulting from the electroplating process is lost. Moreover, whatever the process, it is very difficult to obtain assembly precision between two components and, for example, a pivoting arbour.
It is an object of the present invention to overcome all or part of the aforementioned drawbacks by proposing a method of fabricating a micro-mechanical component that includes, for example, at least three parts, wherein the precision of said processes is not altered by the assembly precision of the parts.
The invention therefore relates to a method of fabricating a micro-mechanical component with several levels includes the following steps:
Advantageously according to the invention, it is possible to fabricate a part from any process (micro-machining, electroforming, electroerosion, stamping) without handling the part itself, but only said frame and said pin, prior to final assembly of said part. Moreover, the support is used as a guide for fabricating the final component in a more precise manner while still maintaining the precision of the process (micro-machining, electroforming, electroerosion, stamping) used to make each part during step a).
According to other advantageous features of the invention:
Other features and advantages will appear more clearly from the following description, given by way of non-limiting illustration, with reference to the annexed drawings, in which:
As illustrated in
Advantageously according to the invention, the first step 3 of making parts 19, 21 of component 31, 41, 51 can be performed using a micro-machining and/or electroplating process. A micro-machining process, i.e. a process with machining precision approximately equal to or less than a micron, may comprise, for example, photolithography, to form a protective mask on a plate of micro-machinable material, then an etch of the unprotected parts of said plate, for example, deep reactive ion etching. A micro-machinable material may thus consist, for example, of a silicon, crystallised silica or crystallised alumina based material. Of course, other materials may be used.
An electroplating process may include, for example, photolithography, to form a mould in which galvanic growth is carried out. A galvanic growth material may thus consist, for example, of a metal material like pure nickel or nickel-phosphorus. Of course other materials may be used.
Manufacturing step 3 includes at least two distinct formation phases 2, 4. Each phase 2, 4 using said micro-machining and/or electroplating processes is for forming a respective plate 11, 13 as illustrated in
It is thus clear that the final component 31, 41, 51 can be made, either from the same process, or from several different processes. Of course, processes other than micro-machining and/or electroplating, capable of fabricating these plates 11, 13, etc., can be used, such as electroerosion or stamping.
According to the invention, method 1 includes a second step 5 for stacking plates 11, 13 against a support 23. In the example illustrated in
Preferably, according to the invention, each arbour 22 has a shoulder 24 to make the distance between plate 13, 11 and support 23 more accurate. Support 23 preferably also includes alignment means 25 for reliably orienting plate 13, 11 relative to support 23. In the example illustrated in
In a first phase 6 of second step 5 illustrated in
In a second phase 8 of second step 5 illustrated in
It is thus clear that plates 11 and 13 are very precisely positioned relative to support 23, and, incidentally, in relation to each other. It will also be noted that part 21 of plate 13 is located underneath and in contact with part 19 of plate 11. Finally, it can also be seen that, in the example illustrated in
Of course, first and second steps 3 and 5 are not limited to making and stacking two single plates 11 and 13. Indeed, method 1 advantageously enables more or fewer than two plates to be made in step 3 so as to fabricate a component 31, 41, 51 from more or fewer than two stacked parts on support 23 in step 5. It is also clear that more or fewer phases 2, 4 are necessary in step 3 and more or fewer phases 6, 8 are necessary in step 5.
According to the invention, method 1 includes a third step 7 for securing each of the stacked parts 19, 21 to form micro-mechanical component 31, 41, 51. Preferably, according to the invention, securing step 7 is achieved by mounting a pin 29 in holes 16, 18 of each part 19, 21. Thus support 23 preferably also includes a post 27 with a hollow top portion 28 to prevent any relative movement between parts 19, 21 and their plates 11, 13 when pin 29 is inserted into their respective holes 16, 18. Indeed, any such relative movement would involve a risk of breaking bridges of material 12, 14 that is undesirable in this third step 7 of method 1.
Depending upon the nature of the materials used to make plates 11, 13, etc., several embodiments of third step 7 could be envisaged. Thus, according to the invention, the preferred embodiments are driving in, welding and bonding. Of course, if one of plates 11, 13, etc., is made of a material with no or very limited plastic deformation domain, it will be difficult to perform a driving in operation.
In a first, embodiment, related to driving, in the example illustrated in
In a second weld-related embodiment, in the example illustrated in
In a third bonding-related embodiment, in the example illustrated in
According to the invention, method 1 includes a fourth step 9 of releasing the micro-mechanical component 31, 41, 51 formed from each of the plates 19, 21, etc. stacked in second step 5. Step 9 is preferably achieved by exerting a force capable of breaking bridges of material 12, 14.
Preferably, for all of the embodiments of third step 7, pin 29 is secured so that it projects from at least one of the stacked plates and can be used as gripping means, i.e. so that parts 19, 21, etc. of each plate 11, 13, etc. do not have to be handled. Advantageously, method 1 thus makes high surface quality possible for each of the parts. It is also clear that the top hollow part 28 of post 27, mounted on support 23, enables pin 29 to go beyond the bottom of plate 13 and/or limits the extent to which the pin is driven into holes 16, 18, etc.
According to a first variant of the invention, pin 29 has a ring 30 that forms a stop member on said projecting part so as to limit how far pin 29 penetrates the holes in the parts. Ring 30 thus provides an improvement in manufacturing quality. Moreover, ring 30 which can be integral with pin 29 may also, advantageously, comprise a toothing that can form a pinion as explained below.
According to a second variant of the invention, in addition to ring 30, pin 29 can also be extended at each of its ends by a pivot-shank that includes a pivot so as to form a pivoting arbour. Advantageously, according to the invention, it is thus clear that it is possible, in third step 7, to secure a multitude of elements in the holes of the stacked parts, which may vary from a simple pin 29 to a pivoting arbour fitted with at least one pinion.
Upon reading method 1, it is clear that it is possible to form several identical, or non-identical parts 19, 21, etc. on each plate 11, 13, etc. so as to mass produce identical or non-identical final components 31, 41, 51. It is also clear that, after third step 7, plates 11, 13, etc. can be delivered straight to the production lines, of, for example, timepiece movements before fourth step 9 is carried out. The advantage of this is that it is only the frames 15, 17, etc. of plates 11, 13, etc. of many final components that are handled at the same time, without any risk of said stacked parts 19, 21, etc. being damaged by handling.
Advantageously, method 1 thus provides improved fabrication precision, the possibility of fabricating high quality composite components in a flexible manner, i.e. components including several different materials of high quality without having to manipulate the parts of the final component in a very simple manner and with a multitude of plates. It is thus clear that method 1 may be entirely automated, for example, using a multi-station production line.
Micro-mechanical component fabrication examples in accordance with method 1 will now be presented with reference to
In the example illustrated in
Advantageously, according to the first variant explained above, pinions 35, 45 may also be integral with arbours 33, 43 respectively and thus form assemblies that can secure the final components 31, 41 in the third step 7 of method 1.
It is thus clear that a multitude of micro-mechanical components could be fabricated depending upon the materials used, the embodiments used and/or the variants chosen. Thus, by way of example, as illustrated in
Method 1 may, for example, allow pallet assembly 51 to be obtained using silicon-based parts alone. Pallet assembly 51 could be obtained from two plates made by a micro-machining process in step 3, stacked in step 5 on a support 23, with top arm 55 and guard-pin 55′ being secured to main body 57 respectively by means of an arbour 53 and a pin 53′ by bonding in step 7, pallet assembly 51 then being released from said plates by exerting a force on arbour 53 in final step 9.
Of course, the present invention is not limited to the illustrated example but may be subject to various variants and alterations, which will be apparent to those skilled in the art. In particular, in step 5 could include, as illustrated in
Moreover, in order to provide the place where breakage occurs in step 9, as illustrated in
There may also be more or fewer arbour 22-recess 20, 26 assemblies. Further, these recesses 20, 26 may be replaced by recesses that already exist between frame 15, 17 and parts 19, 21 of plates 11, 13.
Finally, all of the components in the above explanation are mounted approximately vertically in each step purely to facilitate understanding of the invention. In fact, the direction of assembly of the components is not limited to directions A, A′ or C. For example, in the case of fabrication of a pallet assembly 51, one could envisage mounting the pallet stones, before, during or after step 5 via a pierced side of frame 15, 17 of plate 11, 13, etc. used to form part 57 and/or top arm 55. Indeed, as the positioning of the pallet stones is very important, assembly against support 23 in phases 6, 8, etc. of step 5 may be used to mount the pallet stones very precisely in an approximately perpendicular direction to direction A, A′, C. More generally, it is clear that at least one sub-part can be mounted on at least one of said parts laterally relative to said plate, before, during or after step 5.
Number | Date | Country | Kind |
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08169687.4 | Nov 2008 | EP | regional |
This is a National Phase Application in the United States of International Patent Application PCT/EP2009/064639 filed Nov. 4, 2009, which claims priority on European Patent Application No. 08169687.4 of Nov. 21, 2008. The entire disclosures of the above patent applications are hereby incorporated by reference.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2009/064639 | 11/4/2009 | WO | 00 | 5/23/2011 |