BACKGROUND OF THE INVENTION:
[0001] This invention relates to an improved method and product for surfacing and/or polishing
lenses and the like. More particularly, this invention relates to a novel gel producing
fining or polishing pad which considerably simplifies the process of fining and/or
polishing lenses.
[0002] In general, the process for producing fine ground or polished surfaces on optical
materials, such as for example on optical lenses, is much the same regardless of the
type of fining or polishing medium employed, or the type of material being processed.
In typical such operations, a fining or polishing pad is moved across the surface
of the material to be processed, while either a slurry containing abrasive particles,
or plain water, is directed in a stream between the pad and the surface to be processed.
[0003] One such prior art process is disclosed in U.S. patent No. 4,138,228, which teaches
the use of a polishing pad having a water soluble, hydrophilic matrix containing unencapsulated
abrasive particles that are rather weakly bonded to the matrix. This pad is used to
conjunction with a constant stream of water, which assists in the release of polishing
particles which are leached or torn from the pad matrix as the latter breaks down
during use. In practice this pad has been found to be unsatisfactory because of the
lack of contact between the released abrasive particles and the work.
[0004] U.S. patent No. 4,255,164 discloses a glass fining pad or sheet having a water insoluble,
microcellular matrix containing abrasive fining particles. When the pad is used with
an aqueous flow or stream its matrix breaks down and allegedly releases the fining
particles at a controlled rate. While being effective for the grinding or fining stages
of surfacing, this type of pad is not effective for polishing, even when using a polishing
grade abrasive.
[0005] U.S. patent No. 4,576,612 discloses a polishing pad having a water soluble matrix
containing polishing particles. A stream of water which is directed onto the interface
between the pad and the work causes the exposed surface of the matrix slowly to dissolve
thus slowly releasing polishing particles.
[0006] U.S. patent No. 3,042,509 also discloses a wax-like, polyethylene based polishing
compound containing polishing particles, and adapted to be rubbed onto the surface
of a buffing wheel or lap to provide both lubricating and polishing properties for
the wheel or lap surface. The compound is water-soluble so that it can be washed off
of the wheel after the buffing operation.
[0007] Still other such prior art processes showing desirability of directing a slurry or
other liquid in a stream to the interface between the work and a grinding or polishing
pad are disclosed in U.S. patents No. 3,921,344; 3,959,935; 3,522,680; 3,225,497,
3,128,580 and 2,886,923.
[0008] None of the above-noted patents, however, discloses a pad designed to produce an
abrasive gel upon being wetted. Moreover these prior art processes involve several
problems, including the following:
A. It is difficult to keep the abrasive particles suspended in the liquid slurry or
stream; or in other words, to prevent the settling out of the particles.
B. Large amounts of abrasive particles tend to stick to and to dry upon the processing
equipment.
C. Frequent repair and replacement of pumps, which are used to circulate the abrasive
slurry, are necessary.
D. It is extremely difficult to mix and control the concentration of the abrasive
slurry.
[0009] One object of this invention, therefore, is to provide an improved fining or polishing
process which eliminates the need for directing a stream of water or liquid slurry
onto the work, thereby circumventing many of the problems associated with the previously
mentioned processes.
[0010] To this end it is an object also to provide a novel fining or polishing pad which
in the presence of a small amount of water forms a very viscous gel, which adheres
both to both the object being polished and to the pad substrate.
[0011] Still another object is to provide a novel water absorbent or adsorbent pad which,
when wetted, makes all of its abrasive material instantly available for fining or
polishing.
[0012] A further object of this invention is to provide a novel pad of the type described
having an abrasive-containing matrix made from a polymer which can absorb and retain
large amounts of water to enable formation of a long lasting gel.
[0013] Still another other objects of the invention will be apparent hereinafter from the
specification and from the recital of the appended claims, particularly when read
in conjuction with the accompanying drawing.
SUMMARY OF THE INVENTION:
[0014] The hereinafter described pad provides a disposable, self-contained article for fining
or polishing the surfaces of various materials (plastics, metals, glass, ceramics,
etc.) using only a small amount of a liquid agent to produce between the pad and the
work a gel which contains abrasive particles (fining or polishing). The abrasive particles
(aluminum oxide, cerium oxide, etc.) are dispersed in a water absorbent or adsorbent,
gel-producing carrier or matrix, which is coated uniformly onto a flexible reinforcing
substrate, such as for example a fabric of the type used for conventional polishing
or finishing pads. An adhesive is applied to the back of the substrate, and the entire
structure is cut to form a conventionally shaped, multi-petal pad. The pad is attached
to a surfacing lap and its matrix and substrate are wetted with a small amount of
liquid. The motion of the lap forms on the pad a gel, which acts like a viscous slurry
to surface the associated workpiece.
[0015] The optimum abrasive carrier or matrix provides rapid gelation, uniform dispersion
of surfacing agent, lubrication between the lap or other surfacing substrate and the
object being fined or polished, and produces a viscous matrix which retains or prevents
loss of the abrasive. The preferred, matrix-supporting substrate is a fabric capable
of absorbing water to function as a reservoir for the gel produced during use. The
replacement of a slurry with a gel producing matrix eliminates the need for preparing,
storing, and disposing of liquid slurries. It also reduces machine maintenance and
cleanup-time.
THE DRAWING
[0016] In the drawing:
Fig. 1 is a plan view of a gel producing fining or polishing pad made according to
one embodiment of this invention;
Fig. 2 is an enlarged, fragmentary cross sectional view taken generally along line
2-2 in Fig. 1 looking in the direction of the arrows; and
Fig. 3 is a side elevational view of a conventional fining or polishing lap as it
appears with the pad of Fig. 1 secured thereon.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0017] Referring now to the drawing by numerals of reference, 10 denotes generally a gel
producing surfacing pad having therein the usual radial slots 11, which lend to the
pad the conventional appearance of a petal-shaped pad. Pad 10 comprises several parts,
each of which is responsible for a distinct function. For example, 12 denotes the
attachment layer - which, as noted hereinafter is used to attach the pad 10 to a lap
or the like.. This layer 12 may be any adhesive well known to the industry, such as
for example a PSA adhesive.
[0018] Numeral 14 denotes the substrate layer. This layer has several functions. It provides
an intermediate supporting layer between the attachment layer 12 and the hereinafter
described surfacing layer; it provides a pliable surface which keeps the hereinafter
described abrasive particles in contact with the surface which is being polished or
fined; it retains a small amount of abrasive particles in its structure; and in use
it acts a a reservoir for the wetting liquid. Any number of synthetic or natural pliable
sheet materials can be used for the substrate layer 14, including but not limited
to cotton, felt, paper, and woven or non-woven synthetics. These materials can be
a flocked form, or may be altered in other ways (perforated, embossed, etc.) to help
them retain abrasive particles and the surfacing layer or particle carrier layer.
[0019] The surfacing or particle carrier layer is denoted at 15, and comprises, preferably,
a water absorbent matrix 16 containing abrasive particles 17. Layer 15 is the key
component of the gel producing abrasive pad, and as noted hereinafter usually is coated
as a paste onto substrate 14 in the range of approximately 10 milligrams to more than
250 milligrams of paste per square centimeter of the substrate surface. When applied
in this manner, part of the matrix 16 and its particles 17 penetrate to a certain
extent into the fabric substrate (Fig. 2), particularly in those cases where layer
14 is flocked or felted. Layer 15 has multiple functions which should be balanced
to produce a good quality surface in the shortest amount of time. For example, the
abrasive particles 17 preferably have a Knoop hardness of greater than 1000, and are
of a particle size distribution which allows for rapid stock removal with the least
amount of scratches left on the surface. For use as a polishing pad the particles
17 preferably should have an average particle size of 0.1 to 10.0 micrometers or microns,
and for fining pads a range of from 10.0 to 50.0 micrometers is recommended. Abrasives
that can be used include, but are not limited to, cerium oxide, aluminum oxide, silica,
etc.
[0020] The gelling agent or matrix 16, which forms a gel on contact with a liquid, provides
a medium which holds the abrasive particles 17 in the presence of a liquid between
the substrate 14 and the material being surfaced (not illustrated). The matrix 16
is capable of holding relatively large amounts of liquid, which takes on swarf from
the abraded surface, provides lubrication between the pad and the object being surfaced,
and can provide cooling to materials which are heat sensitive. Materials suitable
for creating matrix 16 include cellulose based materials, clays, alumina-silicates,
polymer silicas, and similar materials. Other additives can be used in conjunction
with the gelling agent or matrix 16, such as chemical polishing accelerators, coolants,
oxidation inhibitors, etc.
[0021] Some typical examples of the invention are as follows:
EXAMPLE No. 1 - POLISHING PAD
Preparation of gel/abrasive matrix:
[0022]
Part A) 20 grams of propylene glycol and 10 grams of a sodium carboxymethylcellulose carrier,
such as for example the type known as CMC 7L and sold by Aqualon of Wilmington, Delaware,
were mixed until well dispersed.
Part B) 160 gr. of water, plus 5 gr. of a dispersant known as Darvan 7, which is sold by
Vanderbuilt Co. of Norwalk Conn., and 150 gr. of aluminum oxide, having an average
particle size of approximately 0.0025 mm (2.5 microns), were mixed until well dispersed.
[0023] Part B was then mixed into Part A until the mixture was a smooth paste. Ratio of
abrasive (150 gr.) to dry carrier (10 gr.) was 15:1.
[0024] The mixture of parts A and B was then coated as a layer 15 onto a pad substrate 14
which comprised of a commercially availlable flocked polyester fabric such as 0.5
mm (0.020 inch) rayon flock sold by Tempo/Shane of Peabody Mass.
[0025] The layer 15 of paste was coated on substrate 14 to a thickness of approximately
0.13-0.2 mm (0.005 - 0.008 inches). The fabric substrate 14 was then placed in an
oven at 184°C (300° F). for five minutes. After cooling the fabric, a pressure sensitive
adhesive layer 12 was attached to the back of layer 14, and pad 10 was cut to its
desired shape using a steel rule die.
TESTING
[0026] Each of a first set of polishing pads made according to Example No. 1 was mounted
on a lap 20 and saturated with about 20 ml. of water, enough to wet the matrix 16
and to saturate the reservoir layer or substrate 14. The lap was put on a Coburn 505
polishing machine set on low speed and at a pressure of at 1.4 kg/cm² (20 psi). A
fined plastic lens (Supremacy 65 from Coburn Optical Industries, Muskogee, OK.) was
mounted and (polished) run for three minutes for each pad.
[0027] A second set of pads was prepared and run using the same procedure, except that in
preparing part A of Example No. 1, the amount of propylene glycol was increased to
40 grams, and each pad was not saturated with water.
[0028] A third set of pads was prepared and run using the same gel/abrasive matrix and polyester
fabric as in the first set, but the uncoated pad fabric was first attached to the
lap, after which 4 grams of paste was smeared onto each pad.
RESULTS:
First Set of Pads
[0029]
- Number of tests
- : 10
- Range of removal
- : 15 mg. to 31 mg.
- Average removal
- : 25 mg.
- Surface quality
- : Equal to current industry standards
- Optical quality
- : Very Good
Second Set of Pads
[0030]
- Number of tests
- : 3
- Range of removal
- : 10-21 mg.
- Average removal
- : 14.3
- Surface quality
- : Equal to low quality commercial lens.
- Optical quality
- : Passable
Third Set of Pads
[0031]
- Number of tests
- : 1
- Removal
- : 23 mg.
- Surface quality
- : Equal to industry standard
- Optical quality
- : Very good
EXAMPLE No. 2 - FINING
[0032] Preparation of gel/abrasive matrix:
Part A) 150 grams of Fine-Rite .025 Alumina, produced by Ferro Corp., Penn Yan, N,Y., plus
100 grams of deionized water, and 5 grams of Darvan 7, all of which were mixed until
well dispersed.
Part B) 15 grams of carboxymethylcellulose (CMC 7L) plus 23 grams of propylene glycol were
mixed until well dispersed. Part B was then mixed into Part A under agitation. Ratio
of abrasive (150 gr.) to dry carrier (15 gr.) was 10:1.
[0033] This mixture was coated as a layer 15 onto a 0.13 mm (0.005 inch) glass- polishing
fabric substrate, which was the type sold by Pellon of Chelmsford, Ma., at a thickness
of 0.13 mm (.005 inches), and placed in a 184°C (300° F). oven until dry. The cooled
material was laminated to a pressure sensitive adhesive layer 17 and a multi-petal
pad was die-cut from this material.
TESTING
[0034] The fining pad of Example No. 2 was mounted on a lap 20 and saturated with about
20 milliliters of water. The lap was put on a Coburn 505 polishing machine set on
low speed at a pressure of 1.4 kg/cm² (20 psi). A plastic lens was mounted and run
(fined) for two minutes by the pad of Example No. 2.
RESULTS: Finishing Pad
[0035]
![](https://data.epo.org/publication-server/image?imagePath=1993/10/DOC/EPNWB1/EP89119666NWB1/imgb0001)
EXAMPLE No. 3 - POLISHING
[0036] 20 grams of alumina having an average particle size of approximately 0.0025 mm (2.5
micron) was mixed with 8 grams of Clay Bentone SD-1 (NL Chemicals) and 25 grams of
deionized water until well dispersed. Ratio of abrasive (20 gr.) to dry carrier (8
gr.) was 2.5:1.
TESTING
[0037] The paste was coated on a flocked polyester pad or substrate 14, which was then attached
to a polishing lap. The lap was attached to a Coburn 505 polishing machine and run
for three minutes on low speed at a pressure of 1.4 kg/cm² (20 psi). A plastic lens
was used.
RESULTS: Polishing Pad
[0038]
![](https://data.epo.org/publication-server/image?imagePath=1993/10/DOC/EPNWB1/EP89119666NWB1/imgb0002)
[0039] As used herein the term gel is intended to have its common meaning such as for example
of substance which is a colloid in which the disbursed phase has combined with the
continuous phase to produce a semisolid material, such as a jelly.
[0040] From the foregoing, it will be apparent that the present invention considerably simplifies
the process and apparatus heretofore required to fine grind and/or to polish rigid
surfaces, such as for example the surfaces of optical lenses. By using a special gel-producing
pad, it is possible to eliminate the need for directing a stream of liquid slurry
or water onto the interface between a pad and lens, for example, thus eliminating
also the need for using recirculating pumps and/or filters for directing a slurry
continuously onto the work during a surfacing operation. With the novel pad disclosed
herein it is necessary only to wet the surface of the pad at the commencement of a
surfacing operation, and possibly to squirt a supplemental amount of liquid onto the
pad during prolonged surfacing operations. In any event, it is not necessary continuously
to direct a stream of liquid onto the pad because of the gel-like coating formed thereon
at the outset of the operation. To prevent the dry carrier or matrix forming material
from diluting the cutting effect of the abrasive it is preferred that the ratio of
abrasive to dry carrier be kept as high as possible.
[0041] Obviously pads of the type disclosed herein can be utilized to surface rigid products
or work pieces other than optical lenses, for example in the lapidary and gem making
art. Also, while other organic compounds could be used as gel producing matrices,
such as for example polyvinyl alcohol, polyethelene glycol, alginates, gums, and combinations
thereof, they are not quite as effective as the above-noted water absorbing or retaining
materials such as cellulose based materials and the like. Also, in addition to fabric
substrates such as denoted at 14, other flexible, water absorbing and retaining substrates
could be employed without departing from the invention.
1. An abrasive surfacing article, comprising a flexible substrate, a flexible matrix
layer coated on the surface of said substrate, and a plurality of abrasive particles
dispersed throughout said matrix layer, and characterized by the fact that said matrix
layer comprises a material selected from the group consisting of cellulose based materials,
clays and silicas, gums, polyvinyl alcohol, polyethylene glycol, alginates, and combinations
thereof, and which is operative upon being wetted with a liquid to produce a gel that
holds said particles in the presence of said liquid, and said substrate comprises
a water-absorbent material operative to function as a reservoir for the liquid which
is used to wet said matrix layer.
2. An abrasive surfacing article as defined in claim 1, wherein said abrasive particles
have a Knoop hardness of at least 1000, and an average particle size in the range
of about 0.1 to 50.0 micrometers.
3. An abrasive surfacing article as defined in any one of claims 1 or 2, wherein said
substrate is made of an absorbent fabric.
4. An abrasive surfacing article as defined in any of the preceding claims, wherein the
weight ratio of said abrasive particles to said material comprising said matrix layer
falls in the range of approximately 2.5:1 to 15:1.
5. A method of preparing an optical quality surface on a workpiece, comprising providing
a surfacing pad having a liquid absorbent, flexible substrate coated with a flexible
matrix having a plurality of abrasive particles dispersed therein, applying a liquid
to said matrix and said substrate, and rubbing the surfaces of said workpiece and
said matrix, respectively, one relative to the other, and characterized by the fact
that said matrix comprises a material selected from the group consisting of cellulose
based materials, clays and silicas, gums, polyvinyl alcohol, polyethylene glycol,
alginates and combinations thereof capable of producing a gel, when wetted, and said
liquid is applied to said pad in a quantity only sufficient to saturate said substrate
and to create a viscous abrasive surfacing gel between said workpiece and said pad
substrate.
6. The method as defined in claim 5, including applying said liquid to said pad prior
to commencement of rubbing said one surface relative to the other, and completing
the surfacing of said workpiece without applying any additional liquid to said pad.
7. A method of preparing an optical quality surface on a workpiece, comprising providing
a workpiece and a surfacing pad, preparing a viscous, paste-like, abrasive gel by
mixing water, abrasive particles, and material selected from the group consisting
of cellulose based materials, clays, silicas, gums, polyvinyl alcohol, polyethylene
glycol, alginates and combinations thereof, interposing a layer of said paste-like
gel between said pad and the face of said workpiece that is to be prepared, and rubbing
said surfacing pad against the face of said workpiece while said gel is interposed
therebetween, thereby to remove material from the face of said workpiece without applying
any additional liquid to the interface between said pad and said workpiece.
8. A method as defined in claim 7, including applying said layer of paste-like gel to
said surfacing pad prior to commencement of rubbing said pad against the face of said
workpiece.
1. Abrieb- erzeugender Artikel, enthaltend ein flexibles Substrat, eine flexible Matrix-
oder Basisschicht auf der Oberfläche des Substrates und eine Anzahl von Abriebteilchen,
die innerhalb der Matrixschicht verteilt sind,
dadurch gekennzeichnet,
daß die Matrixschicht ein Material aus der Gruppe enthält oder ist, die Material
auf Cellulosebasis, Seltene Erden und Silikas, Gummi, Polyvinylalkohol, Polyäthylenglykol,
Alginate und Kombinationen hiervon umfaßt, und die beim Anfeuchten mit einer Flüssigkeit
in Aktion tritt, um ein Gel zu erzeugen, das die Teilchen bei Anwesenheit der Flüssigkeit
festhält, und wobei das Substrat ein wasserabsorbierendes Material enthält oder ist,
das als Reservoir für die Flüssigkeit dient, die zum Anfeuchten der Matrixschicht
eingesetzt wird.
2. Artikel nach Anspruch 1, dadurch gekennzeichnet, daß die Abriebteilchen eine Knoophärte
von wenigstens 1000 und eine durchschnittliche Teilchengröße im Bereich von etwa 0,1
bis 50 Mikrometer aufweisen.
3. Artikel nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß das Substrat aus einem
absorbierenden Textilstoff hergestellt ist.
4. Artikel nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß das Gewichtsverhältnis
der Abriebteilchen zum Material, welches die Matrixschicht enthält oder ist, im Bereich
von etwa 2.5:1 bis etwa 15:1 liegt.
5. Verfahren zum Herstellen einer Oberfläche mit optischer Qualität auf einem Werkstück,
bestehend
aus dem Vorsehen eines Kissens zur Behandlung von Oberflächen, mit einem Flüssigkeit-
absorbierenden flexiblen Substrat, das mit einer flexiblen Matrix- oder Basisschicht
beschichtet ist, in der eine Vielzahl von Abriebteilchen verteilt sind,
aus dem Zuführen einer Flüssigkeit an die Basisschicht und das Substrat,
und aus dem Reiben der Oberflächen des Werkstückes und der Basisschicht gegeneinander,
dadurch gekennzeichnet, daß als Basisschicht ein Material aus der Gruppe eingesetzt
wird, die Material auf Cellulosebasis, Seltene Erden und Silikas, Gummis, Polyvinylalkohol,
Polyäthylenglykol, Alginate und Kombinationen zwischen diesen Materialien umfaßt,
und das beim Anfeuchten ein Gel bildet, und daß die Flüssigkeit dem Kissen lediglich
in einer Menge zugeführt wird, die ausreicht, um das Substrat zu sättigen und ein
viskoses Gel zwischen Werkstück und Kissensubstrat für ein gegenseitiges Reiben der
beidseitigen Oberflächen zu erzeugen.
6. Verfahren nach Anspruch 5, gekennzeichnet durch das Aufbringen der Flüssigkeit auf
das Kissen vor dem Beginn des Reibens einer Oberfläche an der anderen, und durch das
Beenden der Oberflächenbehandlung des Werkstückes ohne das Aufbringen irgendeiner
zusätzlichen Flüssigkeit auf das Kissen.
7. Verfahren zum Präparieren einer Oberfläche mit optischer Qualität auf einem Werkstück,
bestehend
aus dem Vorsehen eines Werkstückes und eines Kissens für Oberflächenbehandlung,
aus dem Präparieren eines viskosen breiartigen und Abrieb erzeugenden Gels durch das
Mischen von Wasser, Abriebteilchen und Material, das aus der Gruppe ausgewählt ist,
die Materialien auf Cellulosebasis, Seltene Erden, Silikas, Gummis, Polyvinylalkohol,
Polyäthylenglykol, Alginate und Kombinationen derselben umfaßt,
aus dem Auflegen einer Schicht dieses breiartigen Gels zwischen Kissen und der Oberfläche
des zu präparierenden Werkstückes, und aus dem Reiben des Kissens für die Oberflächenbehandlung
gegen die Fläche des Werkstückes, während das Gel zwischen beiden liegt,
um Material von der Fläche des Werkstückes zu entfernen, ohne irgendwelche zusätzliche
Flüssigkeit zur Zwischenschicht zwischen Kissen und Werkstück aufzubringen.
8. Verfahren nach Anspruch 7, gekennzeichnet durch das Aufbringen der Schicht des breiartigen
Gels auf das Kissen für die Oberflächenbehandlung vor dem Beginn des Reibens dieses
Kissens gegen die Fläche des Werkstückes.
1. Article abrasif de surfaçage, comprenant un substrat flexible, une couche flexible
à matrice sur la surface de ce substrat, et un certain nombre de particules abrasives
dispersées à travers cette couche à matrice, et caractérisée par le fait que cette
couche à matrice contient un matériau sélectionné parmi le groupe de matériaux comprenant
les matériaux à base de cellulose, l'argile et les dioxydes de silicium, les gommes,
l'alcool polyvinylique, le polyéthylène-glycol, les alginates, et les combinaisons
de ces matériaux, et qui devient opératif en étant humidifié avec un liquide pour
former un gel qui retient les particules abrasives en présence de ce liquide, et que
le substrat contient un matériau absorbant l'eau faisant fonction de réservoir pour
le liquide utilisé pour humidifier la couche en matrice.
2. Article abrasif de surfaçage selon la revendication 1, dans lequel les particules
abrasives présentent une dureté Knoop d'au moins 1000, et une taille moyenne de l'ordre
de 0,1 à 50,0 micromètres.
3. Article abrasif de surfaçage selon la revendication 1 ou 2, dans lequel le substrat
est fait d'une étoffe absorbante.
4. Article abrasif de surfaçage selon l'une des revendications précédentes, dans lequel
le rapport du poids des particules abrasives au poids du matériau contenant la couche
en matrice est compris entre les rapports approximatifs de 2,5:1 et 15:1.
5. Procédé de préparation d'une surface de qualité optique sur une pièce à usiner, comprenant
la fourniture d'un coussin de surfaçage doté d'un substrat flexible absorbant le liquide
et enduit d'une matrice flexible dotée d'un certain nombre de particules abrasives
y dispersées, l'application d'un liquide à cette matrice et à ce substrat, et le frottage
des surfaces de la pièce à usiner et de la matrice l'une par rapport à l'autre, et
caractérisé par le fait que la matrice contient un matériau sélectionné parmi le groupe
de matériaux comprenant les matériaux à base de cellulose, l'argile et les dioxydes
de silicium, les gommes, l'alcool polyvinylique, le polyéthylène-glycol, les alginates,
et les combinaisons de ces matériaux, capable de produire un gel lorsqu'il est humidifié,
et que ce liquide est appliqué sur le coussin dans un quantité juste suffisante pour
saturer le substrat et pour créer un gel de surfaçage abrasif et visqueux entre la
pièce à usiner et le coussin de substrat.
6. Procédé selon la revendication 5, incluant l'application du liquide sur le coussin
avant de commencer à frotter une surface par rapport à l'autre, et terminant le surfaçage
de la pièce à usiner sans appliquer aucun liquide supplémentaire au coussin.
7. Procédé de préparation d'une surface de qualité optique sur une pièce à usiner, comprenant
la fourniture d'une pièce à usiner et d'un coussin de surfaçage, la préparation d'un
gel visqueux d'une consistance pâteuse et abrasif en mélangeant de l'eau, des particules
abrasives, et un matériau sélectionné parmi le groupe de matériaux comprenant les
matériaux à base de cellulose, les argiles, les dioxydes de silicium, les gommes,
l'alcool polyvinylique, le polyéthylène-glycol, les alginates et les combinaisons
de ces matériaux, l'interposition d'une couche de ce gel d'une consistance pâteuse
entre le coussin et la surface à travailler de la pièce à usiner, et le frottement
du coussin de surfaçage contre la surface de la pièce à usiner alors que le gel est
interposé entre les deux, en retirant le matériau de la surface de la pièce à usiner
sans appliquer aucun liquide supplémentaire à l'interface entre le coussin et la pièce
à usiner.
8. Procédé selon la revendication 7, incluant l'application d'une couche de gel de consistance
pâteuse au coussin à surfacer avant de commencer à frotter le coussin contre la surface
de la pièce à usiner.