EP1131186B1 - Lapping and polishing device - Google Patents

Abstract

The invention concerns a polishing or lapping device comprising a surface whereon parts to be polished are to be applied, with an interposed abrasive suspension and with a certain pressure. The invention is characterised in that said surface comprises a plurality of recessed parts (1, 16, 17) forming reservoirs for the abrasive suspension independent of one another and said recessed parts (1, 6, 17) are defined by partitions (2, 26, 27) whereof the top walls (20), co-operating with said abrasive suspension, form active zones for lapping or polishing, said partitions (2, 26, 27) having a substantially constant height over the whole surface of the device, before it is used. The invention is useful for polishing or lapping metal parts.

Description

The invention relates, according to a first of its aspects, to a polishing or lapping device comprising a surface selectively rotated around an axis of revolution and on which parts to be polished are intended to be applied, with the interposition of a abrasive suspension and with a certain pressure, this surface comprising a plurality of recessed parts forming, for the abrasive suspension, reservoirs which are independent of each other and the parties in hollow being delimited by partitions whose walls in cooperation with the abrasive suspension, form the active areas for lapping or polishing.

Devices of this type can in particular be presented in the form of a disc or a cylinder.

The document. EP-0 370 843 describes a polishing plate having a flat surface to which are exposed soft parts and hard parts. These tender parts and hard are distributed appropriately to adjust the length of the intervals between the hard parts.

This significantly increases the yield of the polishing pad, i.e. the amount of material removed per unit of time.

However, the fact remains that the manufacture of this tray is relatively complex.

A device of the previously defined type is described in U.S. Patent 5,297,364.

According to the teaching of this earlier patent, the partitions delimiting the abrasive suspension tanks have a different height depending on whether they are open or closed, side walls of these partitions form with the walls upper walls of these partitions at a right angle, and tanks and partitions are distributed so irregular both in a radial direction and in a tangential direction.

However, the effectiveness of this device remains limited.

The invention aims to overcome these drawbacks by proposing a lapping or polishing device, the manufacturing is simplified and whose yield is increases.

To this end, the device of the invention, moreover conforms to the generic definition given in the preamble above, is characterized in that the partitions have a substantially constant height over the entire said surface of the device, before using this one, in that the hollow parts are delimited by side walls forming with the walls greater than an angle less than 90 °, and in that the recessed parts and the partitions are distributed so regular on each circle centered on the axis of revolution.

Preferably, the ratio between the smallest thickness of said partitions and the largest dimension of the parts intaglio is between approximately 1: 3 and 1: 6 and, from preferably 1: 5.

Preferably, the depth of the recesses or the partition height is between 0.05 and 15 millimeters and, in particular, between 0.05 and 10 millimeters.

In addition, the thickness of the upper walls of the partitions is advantageously between 0.5 and 15 mm.

The angle between the side walls and the top wall of a partition is advantageously greater than or equal to 75 °.

To ensure regular polishing or running-in of parts to be polished, the recessed parts and the partitions are preferably evenly distributed throughout said device surface.

For a lapping or polishing device that presents itself in the form of a disc, the surface of the walls upper partitions advantageously increases since the edge of the disc toward the center of the disc.

The lapping or polishing device according to the invention preferably consists of at least one resin synthetic mixed with at least one powder, in particular with metal or ceramic base.

Abrasive grains, in particular based on aluminum oxides, silicon carbides or natural diamond or synthetic, can be mixed with said resin.

In one embodiment of the device according to the invention, partitions define shapes geometric type polygonal or rounded.

In another embodiment of the lapping device or polishing according to the invention, its surface corresponds to relief in positive or negative of a taffeta type fabric or satin.

• à verser, dans un moule de forme appropriée, un mélange d'au moins une résine synthétique et au moins une poudre, notamment à base de métal ou de céramiques, comportant éventuellement des grains abrasifs,
• à laisser durcir ledit mélange et
• à procéder au démoulage.

The invention relates, according to a second of its aspects, to a process for obtaining a polishing or lapping device as defined above, this process being characterized in that it consists:

• pouring, into a mold of suitable shape, a mixture of at least one synthetic resin and at least one powder, in particular based on metal or ceramics, optionally comprising abrasive grains,
• allowing said mixture to harden and
• to demold.

In an example of implementation of the method, the mold consists of the negative reproduction of a grid and a plate obstructing it.

In another example of implementation of the method, the mold has a surface whose relief is that of a taffeta or satin type fabric or its negative.

• la figure 1 est une vue en plan d'un exemple de réalisation d'un dispositif de rodage ou de polissage selon l'invention, se présentant sous la forme d'un disque ;
• la figure 2 est un détail de la figure 1 ;
• la figure 3 est une vue en coupe selon III-III de la figure 2 ;
• la figure 4 est une vue de détail en plan d'une variante de réalisation du dispositif illustré aux figures 1 à 3 ;
• la figure 5 est une vue en coupe selon V-V de la figure 4 ;
• la figure 6 est une vue de détail en plan d'un autre exemple de réalisation du dispositif selon l'invention ;
• la figure 7 est une vue de détail en plan d'encore un autre exemple de réalisation du dispositif selon l'invention ;
• la figure 8 est une photographie d'un tissu du type taffetas, vu en plan, à une échelle de 200 µm ;
• la figure 9 est une vue photographie d'un tissu du type satin, vu en plan à une échelle de 400µm ;
• la figure 10 est une vue en plan d'un autre exemple de réalisation d'un dispositif selon l'invention, se présentant sous la forme d'un disque.

The invention will be better understood and other objects, advantages and characteristics thereof will appear more clearly on reading the description which follows and which is given in relation to the appended drawings, in which:

• Figure 1 is a plan view of an embodiment of a lapping or polishing device according to the invention, in the form of a disc;
• Figure 2 is a detail of Figure 1;
• Figure 3 is a sectional view along III-III of Figure 2;
• Figure 4 is a detailed plan view of an alternative embodiment of the device illustrated in Figures 1 to 3;
• Figure 5 is a sectional view along VV of Figure 4;
• Figure 6 is a detailed plan view of another embodiment of the device according to the invention;
• Figure 7 is a detailed plan view of yet another embodiment of the device according to the invention;
• FIG. 8 is a photograph of a fabric of the taffeta type, seen in plan, on a scale of 200 μm;
• FIG. 9 is a photographic view of a fabric of the satin type, seen in plan on a scale of 400 μm;
• Figure 10 is a plan view of another embodiment of a device according to the invention, in the form of a disc.

Figure 1 shows an embodiment of the device lapping or polishing according to the invention which is presented in the form of a disc, the flat surface of which comprises a plurality of recessed parts 1 which are delimited between them by partitions 2.

As shown more precisely in Figure 2, the parts in hollow 1 here have substantially the shape of a square, the recessed parts being regularly distributed over the disk surface according to the invention.

This disc is intended to be used with a suspension abrasive which is sprayed over the entire surface of the disc. To perform lapping or polishing, the disc is rotated and the parts to be polished are applied to its surface, with a certain pressure.

Thus, the recessed parts 1 form a plurality of tanks for the abrasive suspension.

These tanks are independent of each other, since each tank is delimited by partitions 2. During use of the disc according to the invention, the abrasive suspension, previously sprayed into each tank, is regularly extracted from it.

Furthermore, the partitions 2 are defined by a wall upper 20 and two side walls 21 and 22.

These are the upper walls 20 of the partitions 2 which, in cooperation with the abrasive suspension sprayed on the disc, form the active areas of the disc for lapping or polishing.

These partitions 2 have a height h which is regular over the entire surface of the disc and this, to ensure regular lapping or polishing of the parts to be polished.

This depth h also defines the depth of each hollow part or tank 1.

The work carried out has shown that this height h is advantageously between approximately 0.05 and 15 millimeters and preferably between 0.05 and 10 millimeters. In this range of values, the parties in troughs actually act as reservoirs, while allowing the passage of part of the suspension abrasive on the upper walls of partitions 2, in while using the disc.

Furthermore, it is advantageous that the thickness of the partitions 2 or the z dimension of the upper face 20 of the partitions are between 0.5 and 15 millimeters, this to contribute to the efficiency of material removal, when using the disc according to the invention.

It has also been established that the ratio between the thickness z partitions 2 and the x or y side of the hollow parts 1 is advantageously between approximately 1: 3 and 1: 6 and that this ratio is notably equal to 1: 5.

Furthermore, the draft angle α, between the upper wall 20 of the partition 2 and a side wall 21 or 22 is less than 90 °. This is due the fact that the device according to the invention is advantageously obtained by molding as will be seen in the rest of the description.

Furthermore, it is preferable that this angle is not less than 75 °, so that the active surface of the disc, consisting of all the upper walls partitions 2, is not significantly changed when the disc undergoes wear, after use extended.

In addition, when the angle α is greater than 75 °, it has been possible note that the evacuation of the abrasive suspension and the abraded material is facilitated.

The invention is of course not limited to the form of recessed parts 1 and partitions 2 which is illustrated on the figures.

The recessed parts 1 may have a shape any geometric, in particular polygonal and for example rectangular or hexagonal, or a rounded shape, such as a round or oval shape.

The surface of the lapping or polishing device according to the invention can also correspond to the relief in negative or positive of a fabric, in particular of the satin type or taffeta.

The negative relief of these fabrics defines parts in hollow forming reservoirs for the abrasive solution and raised parts forming partitions between the tanks. The size of the tanks depends on the dimension of the threads of the fabric as well as the armor of this latest.

We refer to Figures 8 and 9 which illustrate respectively a fabric of the taffeta type and a fabric of the satin type. The elements in relief 18 respectively 19 will form the reservoirs of the device according to the invention and the hollow elements 28 respectively 29, the partitions of these measures.

It is the same for the positive relief of these same tissue.

The ranges of values that were previously given for the thickness of the wall, the depth of the tanks, the clearance angle of the partitions as well as the ratio between the thickness of the wall and the dimensions of the parts in hollow are applicable to all forms of parts in hollow and bulkheads, based on depth average of the tanks, the smallest thickness of partitions and the largest dimension of the hollow parts.

This will now be illustrated with reference to FIGS. 6 and 7 which illustrate alternative embodiments of the device according to the invention, also in the form of a disk.

Referring to Figure 6, the recessed portions 16 have the shape of an equilateral triangle and they are delimited by partitions 26.

In this example, the smallest dimension of the tanks 16, corresponding to the height of the triangle, is indicated by x and the largest dimension of the tanks, corresponding to one side of the triangle, by y. So, this is the z / y ratio which is advantageously between approximately 1: 3 and 1: 6.

Referring to Figure 7, the recessed portions 17 have an oval or elliptical shape and are demarcated by partitions 27.

In this example, the smallest dimension of the tanks 17 is indicated by x, corresponding to the minor axis of the ellipse, and the largest dimension of the tanks by y, corresponding to the major axis of the ellipse. In addition, the smaller thickness of the partitions 27 is indicated by z. In this case again, it is the z / y ratio which is advantageously between approximately 1: 3 and 1: 6.

The invention is also not limited to a device for lapping or polishing in the form of a disc with a flat surface.

Thus, the disc may have a concave surface or convex. Furthermore, the device can also be present in the form of a cylinder, the active surface of polishing or lapping being formed by the surface outer surface or the inner surface of the cylinder.

In general, the device according to the invention is a surface of revolution whose axis of revolution is the axis of rotation of the device on the lapping machine or polishing on which it is used.

For regular polishing or lapping, the recessed parts and the partitions are evenly distributed over any curve defining a plane perpendicular to the axis of revolution of the device and all points of which are equidistant from the axis of revolution.

Thus, for a lapping or polishing device according to the invention of cylindrical shape, the hollow parts and the partitions are evenly distributed over the entire surface of the device which is intended to receive parts to be polished.

For a device in the form of a disc, the hollow parts and the partitions are distributed evenly on any circle of any radius.

This is illustrated in Figure 10 which shows a disc of lapping or polishing according to the invention, the parts of which in the hollow have the shape of a trapezoid.

These recessed parts are distributed in seven circles concentric. All recessed parts 100, 101, 102, 104, 105, 106 respectively defining a circle of the same radius, have the same shape and the same dimensions. On the other hand, from one circle to another, these hollow parts have a different shape and dimensions.

When the device according to the invention is presented under the shape of a disc, its wear, when in use is longer in the center of the disc than on the edge of it.

To reduce the wear gap between the center and the edge of a disc according to the invention, it is desirable that the surface of the upper walls of the partitions or the thickness of the partitions is greater at the level of the center of the disc only towards its edge. In this case, the surface tanks may be smaller towards the center of the disc only at its edge. We can thus foresee that the surface of the upper walls of the partitions increases from the edge of the disc to the center of the disc and this, evenly along a diameter of the disc.

In this regard, reference is made to FIGS. 4 and 5.

Figure 4 shows in plan, a detail of a variant of realization of the device illustrated in figures 1 to 3.

This detail shows a particular distribution of the parts recessed and partitions according to a diameter of the device according to the invention, in the form of a disc. The right part of Figure 4 corresponds to an area of the disc closer to the center of the disc, while the left part of this figure corresponds to an area more close to the edge of the disc.

So, with this distribution, the dimensions of the parts in hollow in the shape of a square decreasing by then the edge of the disc toward the center of the disc, while the thickness of the partitions between the hollow parts goes increasing from the edge of the disc towards the center of the disk.

The thickness zb of the partition 24b between the hollow parts 14c and 14b is therefore greater than the thickness za of the partition 24a between the hollow parts 14b and 14a.

In the example illustrated, the side xc of the hollow part 14c is lower than the side xb of the recessed portion 14b which is itself lower than the side xa of the hollow part 14a.

However, to compensate for disc wear between the edge and the center, it is enough that the thickness of the partitions is more important towards the center of the disc than towards the edge, the dimensions of the hollow parts being substantially identical.

The device according to the invention is advantageously obtained by molding a material consisting of a pure metal or another composite metal, i.e. at least one resin synthetic mixed with at least one solid powder, in particular metallic or also based on ceramics.

In this case, it is possible in particular to use a resin of the type polyurethane or polyester and metallic powders iron, copper, lead, tin, zinc, aluminum or even stainless steel.

The mold has the shape of the desired counterpart, so to obtain the recessed parts and the desired partitions. So practically a mold will have domes, each dome representing a tank.

The mold may consist of the negative reproduction of a grid whose voids represent the partitions and which is associated with a plate which obstructs it.

The use of this mold is advantageous when the partitions of the device according to the invention, which constitute its active part, must be made of a material relatively expensive. Indeed, with this mold, the bottom of tanks can then be realized separately in another any material.

A mold used to make a device according to the invention can also be in the form of a stamped plate on which the tanks are reproduced.

This mold may also have a surface whose relief is that of a taffeta or satin type fabric (see Figures 8 and 9) or the relief in negative of such tissue.

The tests that have been carried out have shown that the lapping or polishing devices according to the invention have significant advantages over devices known in the state of the art.

As indicated above, a device according to the invention is used in combination with an abrasive suspension which is sprayed on its surface.

This spraying supplies each reservoir with the surface of the device.

During lapping or polishing itself, i.e. when parts to be polished or lapped are applied to the device according to the invention, the parts distribute the abrasive suspension on the surface of the device.

Tests have shown that for devices according to the invention, the distribution of the abrasive suspension is practically immediate.

The cleaning of the devices according to the invention is carried out periodically and manually, the abraded material largely depositing in tanks.

• un disque commercialisé par la société demanderesse sous la dénomination "New Lam", du type disque bleu pour ébauche et conforme aux enseignements du brevet européen N° 0 370 848. Ce disque comporte donc une surface plane avec des parties dures, ici réalisées avec une résine synthétique et des particules de fer dont la granulométrie est inférieure à 50 microns et des parties tendres réalisées avec la même résine synthétique mélangées avec des particules de cuivre dont la granulométrie est inférieure à 20 microns,
• et un disque conforme à l'invention obtenu par moulage d'une matière constituée de la même résine synthétique que le disque New Lam décrit ci-dessus, mélangée avec des particules de fer dont la granulométrie est inférieure à 40 microns. La surface de ce disque selon l'invention comporte une pluralité de parties en creux présentant la forme de carrés dont les côtés x, y sont égaux à 3 millimètres, ces carrés étant séparés par des cloisons dont l'épaisseur z est de 0.6 millimètres. De plus, la hauteur h des cloisons ou encore la profondeur des parties en creux est de 0.43 millimètres, tandis que l'angle α entre la face supérieure et une paroi latérale de chaque cloison est égal à 80°. Par ailleurs, la répartition des parties en creux et des cloisons est régulière sur toute la surface du disque.

In addition, comparative tests were carried out between:

• a disc marketed by the applicant company under the name "New Lam", of the blue disc type for roughing and in accordance with the teachings of European patent No. 0 370 848. This disc therefore has a flat surface with hard parts, here produced with a synthetic resin and iron particles with a particle size less than 50 microns and soft parts made with the same synthetic resin mixed with copper particles with a particle size less than 20 microns,
• and a disc according to the invention obtained by molding a material made of the same synthetic resin as the New Lam disc described above, mixed with iron particles whose particle size is less than 40 microns. The surface of this disc according to the invention comprises a plurality of hollow parts having the shape of squares whose sides x, y are equal to 3 millimeters, these squares being separated by partitions whose thickness z is 0.6 millimeters. In addition, the height h of the partitions or the depth of the hollow parts is 0.43 millimeters, while the angle α between the upper face and a side wall of each partition is equal to 80 °. Furthermore, the distribution of the recessed parts and the partitions is regular over the entire surface of the disc.

The test conditions are as follows:

We use a metallography machine whose plate has a diameter of 200 millimeters, corresponding to the diameter of the disc according to the invention and of the New Lam disc blue described above. The machine table turns a speed of 150 rpm.

The tests are carried out with three samples, the dimensions are 10 x 20 millimeters, type 316 LS, coated in a resin and having a final diameter of 40 millimeters.

These three samples are placed in a sample holder and during running-in, the pressure applied is from 9.5 kg.

Lapping is carried out in six cycles of 10 minutes each.

Material removal is measured at the end of each cycle by measuring the difference in weight. The measurements are data in milligrams.

• dans l'essai A, chaque plateau a été nettoyé à l'issue de chaque cycle de 10 minutes,
• dans l'essai B, les plateaux ne sont pas nettoyés entre les cycles.

les résultats sont regroupés dans le Tableau 1 ci-dessous : Enlèvement de matière Durée
cycle
10 minutes ESSAI A
(Nettoyage plateau entre chaque cycle) ESSAI B
(sans nettoyage plateau entre cycle ) NL Disc bleu
standard Disque selon
l'invention NL Disc bleu
standard Disque selon
l'invention 1^er cycle 33 95 34 93 2^nd cycle 32 96 35 90 3^ème cycle 31 97 37 89 4^ème cycle 31 97 30 91 5^ème cycle 31 96 24 93 6^ème cycle 31 96 20 92 TOTAL 189 577 180 548 Two types of tests were carried out:

• in test A, each tray was cleaned at the end of each 10-minute cycle,
• in test B, the plates are not cleaned between cycles.

the results are collated in Table 1 below: Material removal duration
cycle
10 minutes TEST A
(Plate cleaning between each cycle) TEST B
(without tray cleaning between cycles) NL Disc blue
standard Disc according to
the invention NL Disc blue
standard Disc according to
the invention ^1st cycle 33 95 34 93 2 ^nd cycle 32 96 35 90 ^3rd cycle 31 97 37 89 ^4th cycle 31 97 30 91 ^5th Cycle 31 96 24 93 6 ^th cycle 31 96 20 92 TOTAL 189 577 180 548

The results obtained show that the performance of the disc according to the invention, that is to say the amount of material removed per unit of time, is three times greater than that of the blue New Lam disc used for the tests.

Thus, these tests show that the disc according to the invention significantly increases the yield of polishing or lapping.

The following reasons can be put forward to explain that the device according to the invention makes it possible to obtain a more material removal, compared to a disc of the type described in patent EP-0 370 843, without these limit the scope of the invention:

For a disc of the type described in patent EP-0 370 843, the entire surface of the disc constitutes a contact surface with the piece to be polished. On the contrary, in a disc according to the invention, only the upper faces of the partitions may be in contact with the workpiece.

As long as the workpiece is applied, whatever either the disc, with the same pressure, the pressure at level of active surfaces will be more important for a disc according to the invention only for a disc of the type described in patent EP-0 370 843. This higher pressure at the active surfaces contributes to increase removal of material.

We can also consider that, for the lapping or polishing according to the invention, the presence of recessed parts and partitions creates an acceleration of abrasive particles present in the abrasive suspension, between the hollow parts forming reservoirs and the upper part of the partitions constituting a surface active for running in.

In this respect, it can be considered that, insofar as the larger surface of the workpiece to be polished or lapped that the surface of the tanks, applying the part to polishing on the device creates a suction phenomenon which sucks the abrasive suspension present in the tanks.

These tests also show that the device according to the invention can be used without the need to clean it between each running-in or polishing cycle, which is a significant time saver during lapping or polishing operations.

On the contrary, for the blue New Lam disc, the absence of cleaning results in degradation of the abrasive film. This degradation is indicated in gray on the table. She appears from the fourth running-in or polishing cycle.

Indeed, from the fourth cycle, the abrasive film is no longer regular and it is necessary to stop machine for cleaning the plate, lapping or polishing cannot be achieved.

Additional tests were carried out to measure the regularity of the surface of the samples, after the six running-in cycles.

The roughness of the samples obtained after polishing on the two discs was measured with a roughness tester at MAHR PERTHEN type probe.

The measurements carried out showed that the total roughness, or Rt, is 1.2 microns with the blue New Lam disc and 0.9 micron with the disc according to the invention.

Furthermore, the average roughness, or Ra, is 0.11 micron with the blue New Lam disc and 0.08 micron with the disc according to the invention.

Thus, the disc according to the invention makes it possible to obtain a state which is improved by around 30%.

Lapped samples with each of the discs described above were also subject to a surface inspection with a Leitz light microscope.

We have also seen that the samples run in with the disc according to the invention had a surface whose regularity is improved compared to ground samples with the previously described blue New Lam disc.

The above results relating to roughness show another advantage of lapping devices or polishing according to the invention.

Indeed, in general, we want the pieces lapped have an average roughness Ra of less than 0.10 micron.

With a determined number of running-in cycles and a abrasive suspension given, the disc according to the invention described above provides parts whose average roughness Ra is effectively less than 0.10 micron which is not the case for parts run in with the New Lam blue disc previously described.

Thus, to obtain lapped parts whose roughness Ra average is less than 0.10 micron, with the New disk Blue lam, it will be necessary to use a suspension abrasive whose abrasive grains have a particle size smaller than that used in the tests precedents. Consequently, the running-in time will be necessarily longer.

Thus, the lapping or polishing device according to the invention makes it possible to reduce the running-in time or polishing compared to conventional discs, obtaining a similar roughness.

In addition, the disc according to the invention allows a lot greater maneuverability when running in manually.

Another comparative test was carried out to measure the wear of the two discs described above.

These measurements were taken after two hours of running-in.

• un point proche du centre du disque,
• un point situé à mi-rayon et
• un point proche de la périphérie du disque.

For each platter, a double measurement was made at three different points distributed according to the radius of each disc:

• a point near the center of the disc,
• a point located at mid-radius and
• a point close to the periphery of the disc.

The measurements were made using a micrometer and each result is the average of two measurements.

These measurements have been confirmed, for the disc according to the invention, by a measurement, carried out under a microscope, of the difference in level between the bottom of a recessed part or tank and the upper face of a partition or surface of lapping.

All the results obtained are collated in the table below, the measurements being given in microns. Wear Measurements taken after 2 hours of running-in CENTER MI-MAYON EDGE NL Disc Blue 80 55 45 Disc according to the invention 70 50 40

The results reported in this table show that the disc according to the invention improves by about 10% resistance to wear, compared to a disc of the type described in patent EP-0 370 843.

It was previously indicated that the device according to the invention could be obtained by molding a material consisting of pure metal or composite metal, i.e. a mixture of at least one synthetic resin and minus a solid, especially metallic, powder.

The material used to make the lapping device or polishing according to the invention can be unique. we can also plan to make the device according to the invention from two or more different materials, in the case where one wishes to obtain on the surface of the device with different hardness zones.

For example, a first constituent material of device according to the invention can be a mixture of resin polyester and a metallic powder, while a second constituent material may be a mixture of polyurethane resin and another metallic powder.

In addition, the material of the device according to the invention may include abrasive grains, in particular based on aluminum oxides, silicon carbides, or still natural or synthetic diamond.

Finally, it can be noted that the device according to the invention can be in the form of a fixed sheet of removably on a support of suitable shape, by any suitable means. The device according to the invention can also form in one piece the active surface for abrasion and its support.

The invention is of course not limited to the different modes of realization which have just been described and it includes all their technical equivalents, as well as their combinations if these fall within the scope of claims.

Finally, the reference signs inserted after the technical characteristics appearing in the claims are intended only to facilitate the understanding of these and cannot limit their scope.

Claims (14)

1. Polishing or lapping device comprising a surface selectively set in rotation around an axis of revolution and on which elements to be polished are to be applied with the insertion of an abrasive suspension and with a certain pressure, said surface comprising a plurality of hollow portions (1, 16, 17) forming for the abrasive suspension independent tanks, the hollow portions (1, 16, 17) being delimited by partitions (2, 26, 27) whose upper walls (20) together with the abrasive suspension form the active zones for lapping or polishing, characterised in that the partitions (2, 26, 27) have an approximately constant height on the entire said surface of the device before the latter is used, in that the hollow portions are delimited by lateral walls (21, 22) forming with the upper walls (20) an angle (α) less than 90°, and in that the hollow portions (1, 16, 17) and the partitions (2, 26, 27) are distributed evenly on each circle centered on the axis of revolution.
2. Device according to claim 1, characterised in that the ratio between the smallest thickness (z) of said partitions (2, 26, 27) and the largest dimension (y) of said hollow portions (1, 16, 17) is between 1 : 3 and 1 : 6 and preferably equal to 1 : 5 .
3. Device according to claim 1 or 2, characterised in that the depth of the hollow portions (1, 16, 17) or the height (h) of the partitions (2, 5, 27) is between 0.05 and 15 millimetres and preferably between 0.05 and 10 millimetres.
4. Device according to one of claims 1 to 3, characterised in that the thickness (z) of the upper walls (20) of the partitions (2, 26, 27) is between 0.5 and 15 millimetres.
5. Device according to one of claims 1 to 4, characterised in that the angle (α) between the lateral walls (21, 22) and the upper wall (20) of a partition (2, 26, 27) is greater than or equal to 75°.
6. Device according to one of claims 1 to 5, characterised in that said hollow portions and said partitions are evenly distributed over the entire said surface of the device.
7. Device according to one of the preceding claims, characterised in that it has the shape of a disk, and in that the surface of the upper walls of said partitions (24a, 24b) increases from the edge towards the centre of the disk.
8. Device according to one of claims 1 to 7, characterised in that it is constituted by at least one synthetic resin mixed with at least one powder, especially a metal or ceramic-based powder.
9. Device according to claim 8, characterised in that abrasive grains, in particular oxide aluminium, silicon carbide or natural or synthetic diamond-based grains are mixed with said resin.
10. Device according to one of claims 1 to 9, characterised in that said partitions (2, 26, 27) define polygonal or rounded type geometrical shapes.
11. Device according to one of claims 1 to 9, characterised in that said surface corresponds to the positive or negative relief of a taffeta or satin type fabric.
12. Method for obtaining a polishing or lapping device according to one of the claims 1 to 11, which consists of :

    pouring into a suitably-shaped mould a mixture of at least one synthetic resin and at least one power, especially a ceramic or metal-based powder, possibly comprising abrasive grains,

    allowing said mixture to harden, and

    removal from the mould.
13. Method according to claim 12, characterised in that said mould consists of the negative reproduction of a grate and a plate obstructing it.
14. Method according to claim 13, characterised in that said mould has a surface whose relief is that of a satin of taffeta type fabric or its negative.

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