US4270316A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for evening out the amount of material removed from discs in polishing
Assignee: Siltronic AG
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Filing: 1979-02-23
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Granted: 1981-06-02
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Expires: 1999-02-23
Abstract
Abstract In conventional polishing machines, uneven transmission of pressure causesifferent degrees of abrasion of the polished discs which results in different thicknesses over one disc and also with respect to other discs in one polishing batch. This problem is solved according to the invention by the provision of soft elastic inserts between the pressure piston and the back of the carrier plate on which the discs to be polished are cemented.
Inventors
- 👤 Hans Kramer
- 👤 Helmuth Kirschner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:37
CPC Classifications
B; B24; B24B; B24B37/00; B24B37/04; B24B37/042
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
97 words
In a process for evening out the amount of material removed from discs in a polishing operation performed with a polishing machine equipped with a polishing plate covered with a polishing cloth, at least one carrier plate having a side which faces the polishing plate on which the discs to be polished are cemented and at least one pressure piston which presses the carrier plate against the polishing plate covered by the polishing cloth, the improvement comprising: placing inserts comprising soft elastic bodies having pressure-equalization cells between said pressure piston and the back of the carrier plate.
Claim 2
Dependent Claim
97 words
In a process for evening out the amount of material removed from discs in a polishing operation performed with a polishing machine equipped with a polishing plate covered with a polishing cloth, at least one carrier plate having a side which faces the polishing plate on which the discs to be polished are cemented and at least one pressure piston which presses the carrier plate against the polishing plate covered by the polishing cloth, the improvement comprising: placing inserts comprising soft elastic bodies having pressure-equalization cells between said pressure piston and the back of the carrier plate.
Claim 3
Dependent Claim
14 words
The process according to claim 1 wherein said soft elastic bodies comprise air-cushion films.
Claim 4
Dependent Claim
37 words
The process according to claim 1 additionally including the step of introducing a heat transfer medium between the pressure piston and the back of the carrier plate in order to offset the heat-insulating effect of the inserts.
Claim 5
Dependent Claim
16 words
The process according to claim 2, wherein said air-cushion films comprise polyethylene films having air cells.
References Cited (Backward Citations)
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US3449870A
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US3603042A
Cited
US3631634A
Cited
US3754359A
Cited
US4020600A
Cited
US4132037A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-06-01 | 1984-12-01 | 1985-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-06-01 | 1988-12-01 | 1989-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-06-01 | 1992-12-01 | 1993-06-02 | $7700.00 | Window Closed / Lapsed |