WO1988008357A1 - Procede pour tailler a facettes des pierres precieuses - Google Patents

Procede pour tailler a facettes des pierres precieuses Download PDF

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Publication number
WO1988008357A1
WO1988008357A1 PCT/US1988/001309 US8801309W WO8808357A1 WO 1988008357 A1 WO1988008357 A1 WO 1988008357A1 US 8801309 W US8801309 W US 8801309W WO 8808357 A1 WO8808357 A1 WO 8808357A1
Authority
WO
WIPO (PCT)
Prior art keywords
lap
facet
film
polishing
faceting
Prior art date
Application number
PCT/US1988/001309
Other languages
English (en)
Inventor
Charles R. Smith
Original Assignee
Smith Charles R
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Smith Charles R filed Critical Smith Charles R
Publication of WO1988008357A1 publication Critical patent/WO1988008357A1/fr
Priority to KR1019890701360A priority Critical patent/KR930004727B1/ko

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B9/00—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor
    • B24B9/02—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground
    • B24B9/06—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain
    • B24B9/16—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain of diamonds; of jewels or the like; Diamond grinders' dops; Dop holders or tongs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B37/00—Lapping machines or devices; Accessories
    • B24B37/04—Lapping machines or devices; Accessories designed for working plane surfaces

Definitions

  • This invention relates to methods of faceting gemstones.
  • flat facets are commonly formed to render the gem aesthetically pleasing.
  • the most popular way of forming flat facets is to mount a stone to a holder, which is termed a dop, of a faceting machine and then to work the surface of the stone with a rotatably driven lap wheel.
  • Lap wheels are typically made of metal such as copper, brass, tin, lead or cast iron, to which an abrasive is added that actually works the stone. These abrasives must be fairly hard, certainly harder than the gemstone to be faceted.
  • Diamond powders and carborundum are abrasives that are commonly employed in early, cutting stages of the faceting process.
  • a series of lap wheels are employed. Initially, a lap wheel having a rough abrasive surface is used to cut the facet. Again, diamond powders and carborundum are commonly used as the abrasive material embedded in the lap wheel working surface. In the cutting phase several laps are used with abrasive powders of increasingly smaller size. As the size of the abrasive decreases the term prepolishing is often used to signify a second phase of the faceting process wherein the facet surface is worked more finely. Again, the size of the abrasive of the lap wheels used continues to decrease until what is termed the polishing phase is entered. Polishing laps used in this final phase commonly employ fine Q diamond powders, cerium, alumina or other polishing agents.
  • Softer materials may be employed as the working agent in polishing, softer stones such as quartz and tourmalines.
  • Harder stones, as previously stated, c require harder abrasive agents such as diamond powders.
  • The. size of the abrasive powders or particles decrease from some 60 microns all the way down in some cases to 1/2 micron or even smaller in average diameter. This is roughly equivalent to a 400 to 50,000 grit range.
  • polishing lap wheels almost invariably produces a surface that is slightly canted from that produced by the prepolish laps. When this occurs it takes a very substantial time to produce the new plane throughout the entire surface area due to the only weakly abrasive nature of the polishing laps. Alternatively, substantial time is taken in attempts at reorientation.
  • a method of faceting gemstones comprises the steps of sequentially cutting a stone with a coarse grit lap to form a flat facet, prepolishing the flat facet with medium and/or fine grit prepolishing laps, and then polishing the flat facet .with a lap film mounted flushly upon the prepolishing lap last employed during prepolishing.
  • a flat facet is cut on a gemstone and prepolished with a series of rotating lap wheels that bear abrasives of increasingly fine grit.
  • the facet is polished by contacting the facet with a lap film held in intimate contact with the working surface of the lap wheel last used in prepolishing.
  • a method of faceting gemstones comprising the steps of sequentially cutting the stone to form a generally flat facet, prepolishing the generally flat facet with a prepolishing lap wheel, and polishing the flat facet with a lap film mounted flushly upon the lap wheel that bears powders or particles of a selected size range. The film is then removed from the lap wheel and the flat facet polished with another lap film mounted flushly upon the same lap wheel that bears powders or particles of a smaller size than those born by the lap film first used.
  • Fig. 1 is a side view of the portion of a faceting machine shown with a gemstone mounted thereto in the process of being faceted.
  • Fig. 2 is a greatly enlarged, fragmentary view of a portion of a gemstone being faceted for purposes of illustrating a problem and solution provided by the present invention.
  • a conventional gem faceting machine which comprises a lap wheel 10, which often is referred to simply as a lap, that is mounted atop a vertically oriented drive shaft 11 which is driven by an electric 0 motor M located beneath a table 12.
  • the lap 10 is mounted atop a base lap wheel that is mounted upon the drive shaft 11 and secured thereto by a nut or bolt which protrudes centrally above the upper surface of the lap.
  • the mounting is
  • JL JL effected exclusively on the bottom of the lap as by being threaded into a hole in the bottom.
  • Adjacent to the motor driven lap wheel is located an elevator 15 that is movably mounted upon an upright track 16.
  • the elevator may be held fixedly to the track at various Q elevations by means of a set screw 17. With some faceting machines the upright member 16 is threaded as a screw while with others it is not.
  • the elevator supports a dop stick 20 which is mounted to the bottom of a shaft 21 that in turn is c pivotably mounted to a tiltable frame 22.
  • An index gear 23 is mounted to the shaft 21 for use in adjusting the shaft and locking it in various angular positions about the shaft axis for determining angular locations of the facets of a gemstone G mounted to the bottom of Q the dop stick 20.
  • a locking lever 25 is coupled with the gear 23 for securing it, and thus the gemstone G, in a fixed angular position about the axis of the shaft
  • a faceter may manipulate a gemstone G in c a precise manner by bringing it into contact with the lap 10 and moving it upon its surface in forming a flat facet 26 located in the drawing just above and parallel to the upper surface 19 of lap 10.
  • Fig. 2 illustrates this solution. It should be understood that this figure depicts one very small segment of a lap wheel and facet which has been extremely enlarged for purposes of illustration.
  • lap wheel 10 has a lap film 30 that provides its working surface 19. The film is mounted in intimate, flush contact atop the surface 31 of a lap wheel 32.
  • this tiny fragment of the lap is shown spaced along its convex surface from the concave surface fragment of surface 26 of a gemstone.
  • Such a miniscule concave portion of the lap wheel may well have been caused by a constant traversing of a stone by the faceter in moving the stone back and forth from the outer edge towards the center of the lap wheel during prepolishing or in an early polishing stage.
  • Lap films have heretofore existed as disclosed in U.S. Patent No. 3,916,584.
  • an imperial j c diamond lapping flim disc is commercially sold by the 3M . Corporation for the purpose of polishing video heads.
  • the lap film is formed of plastic which has embedded therein diamond powders less than 60 microns in size. The film may be mounted readily to
  • This film may be applied to prepolishing laps having 600 or higher grit size which is to say some 60 or smaller micron size. However, it has been found preferable to mount the film atop a polishing grade lap wheel having polishing particles or powders of 22 micron or less size.
  • a series of lap films may also be used.
  • the stone may be prepolished with a 600 grit lap wheel and then sequentially polished with a 1,200 grit lap film, a 3,000 grit lap film and finally fine polished with a 50,000 grit film.
  • the same prepolishing lap wheel is, of course, used with each of the lap films with the prior lap film removed each time from the working surface of the prepolish lap wheel.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)

Abstract

Une facette plate (26) est polie à l'aide d'un ruban abrasif (30) monté sur le lapidaire (10) utilisé en dernier lors du prépolissage. De cette manière les irrégularités de surface et l'angle du plan du lapidaire sont maintenus. Ceci permet d'éviter la formation d'égratignures sur la facette.
PCT/US1988/001309 1987-04-20 1988-04-19 Procede pour tailler a facettes des pierres precieuses WO1988008357A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1019890701360A KR930004727B1 (ko) 1987-12-25 1988-12-23 초전도체 배선의 구조

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US4033287A 1987-04-20 1987-04-20
US040,332 1987-04-20

Publications (1)

Publication Number Publication Date
WO1988008357A1 true WO1988008357A1 (fr) 1988-11-03

Family

ID=21910427

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1988/001309 WO1988008357A1 (fr) 1987-04-20 1988-04-19 Procede pour tailler a facettes des pierres precieuses

Country Status (1)

Country Link
WO (1) WO1988008357A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5044123A (en) * 1990-03-22 1991-09-03 Douglas Hoffman Concave-convex faceting method and apparatus
EP0687525A1 (fr) * 1994-06-13 1995-12-20 Read-Rite Corporation Système à roder pour le contournage automatisé

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2024303A (en) * 1933-12-07 1935-12-17 Gall & Lembke Inc Glass polisher
US2544940A (en) * 1948-08-13 1951-03-13 American Optical Corp Polishing pad
GB841690A (en) * 1956-02-07 1960-07-20 Kjeld Tue Grubb Polishing cloth particularly for metallographic purposes
US3144737A (en) * 1962-09-27 1964-08-18 Bausch & Lomb Aluminum foil lens grinding pad
GB1321931A (en) * 1971-05-10 1973-07-04 Wylde Ltd J S Grinding of optical lens blanks
US3818641A (en) * 1972-05-25 1974-06-25 R Long Gem faceting machine
US3959935A (en) * 1975-03-18 1976-06-01 Interoptic Laboratories, Inc. Abrasive pad for grinding lenses
GB2021627A (en) * 1978-05-24 1979-12-05 Minnesota Mining & Mfg An Abrasive-slurry Producing Glass Fining Sheet
US4240232A (en) * 1977-12-30 1980-12-23 Giddings & Lewis, Inc. Coated abrasive superfinishing stone and method of making same
US4258508A (en) * 1979-09-04 1981-03-31 Rca Corporation Free hold down of wafers for material removal
US4274232A (en) * 1977-09-14 1981-06-23 Minnesota Mining And Manufacturing Company Friction grip pad

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2024303A (en) * 1933-12-07 1935-12-17 Gall & Lembke Inc Glass polisher
US2544940A (en) * 1948-08-13 1951-03-13 American Optical Corp Polishing pad
GB841690A (en) * 1956-02-07 1960-07-20 Kjeld Tue Grubb Polishing cloth particularly for metallographic purposes
US3144737A (en) * 1962-09-27 1964-08-18 Bausch & Lomb Aluminum foil lens grinding pad
GB1321931A (en) * 1971-05-10 1973-07-04 Wylde Ltd J S Grinding of optical lens blanks
US3818641A (en) * 1972-05-25 1974-06-25 R Long Gem faceting machine
US3959935A (en) * 1975-03-18 1976-06-01 Interoptic Laboratories, Inc. Abrasive pad for grinding lenses
US4274232A (en) * 1977-09-14 1981-06-23 Minnesota Mining And Manufacturing Company Friction grip pad
US4240232A (en) * 1977-12-30 1980-12-23 Giddings & Lewis, Inc. Coated abrasive superfinishing stone and method of making same
GB2021627A (en) * 1978-05-24 1979-12-05 Minnesota Mining & Mfg An Abrasive-slurry Producing Glass Fining Sheet
US4258508A (en) * 1979-09-04 1981-03-31 Rca Corporation Free hold down of wafers for material removal

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5044123A (en) * 1990-03-22 1991-09-03 Douglas Hoffman Concave-convex faceting method and apparatus
EP0687525A1 (fr) * 1994-06-13 1995-12-20 Read-Rite Corporation Système à roder pour le contournage automatisé

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