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US3276927A
Expired / Lapsed
US
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Smoothing of mechanically drilled holes
Assignee: North American Aviation Corp
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Filing: 1963-07-01
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Granted: 1966-10-04
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Expires: 1983-07-01
Abstract
No abstract record available.
Inventors
- 👤 Robert J Medford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:01
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/10; C23F1/14; C23F1/16; C23F1/18; H; H05; H05K; H05K3/00; H05K3/0011; H05K3/0055; H05K2203/00; H05K2203/07; H05K2203/0779; H05K2203/0786; H05K2203/0789
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
126 words
A PROCESS FOR CHEMICALLY SMOOTHING MECHANICALLY DRILLED HOLES IN A LAMINATED CIRCUIT BOARD HAVING AT LEAST THREE LAYERS, A TOP, AN INTERMEDIATE, AND A BOTTOM LAYER, SAID TOP AND BOTTOM LAYERS BEING COMPRISED OF A METALLIC MATERIAL, SAID INTERMEDIATE LAYER BEING COMPRISED OF AN EPOXY-GLASS DIELECTRIC MATERIAL, COMPRISING THE FOLLOWING STEPS, IMMERSING SAID LAMINATED CIRCUIT BOARD IN A FLUOSULFONIC ETCHANT FOR A SUFFICIENT LENGTH OF TIME OF SMOOTH HOLE WALL PROJECTIONS BY THE USE OF SAID CHEMICAL ETCHANT, SAID FLUOSULFONIC ETCHANT COMPRISING APPROXIMATELY TWO PARTS H2SO4 HAVING A CONCENTRATION OF FROM 93% TO 98% AND APPROXIMATELY ONE PART HF HAVING A RANGE OF FROM 70% TO 100% AND WHEREIN SAID TEMPERATURE IS MAINTAINED WITHIN THE RANGE OF FROM 136* F. TO 142*F., AND RINSING SAID BOARDS.
Claim 2
Dependent Claim
126 words
A PROCESS FOR CHEMICALLY SMOOTHING MECHANICALLY DRILLED HOLES IN A LAMINATED CIRCUIT BOARD HAVING AT LEAST THREE LAYERS, A TOP, AN INTERMEDIATE, AND A BOTTOM LAYER, SAID TOP AND BOTTOM LAYERS BEING COMPRISED OF A METALLIC MATERIAL, SAID INTERMEDIATE LAYER BEING COMPRISED OF AN EPOXY-GLASS DIELECTRIC MATERIAL, COMPRISING THE FOLLOWING STEPS, IMMERSING SAID LAMINATED CIRCUIT BOARD IN A FLUOSULFONIC ETCHANT FOR A SUFFICIENT LENGTH OF TIME OF SMOOTH HOLE WALL PROJECTIONS BY THE USE OF SAID CHEMICAL ETCHANT, SAID FLUOSULFONIC ETCHANT COMPRISING APPROXIMATELY TWO PARTS H2SO4 HAVING A CONCENTRATION OF FROM 93% TO 98% AND APPROXIMATELY ONE PART HF HAVING A RANGE OF FROM 70% TO 100% AND WHEREIN SAID TEMPERATURE IS MAINTAINED WITHIN THE RANGE OF FROM 136* F. TO 142*F., AND RINSING SAID BOARDS.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1969-10-03 | 1970-04-04 | 1970-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-10-03 | 1974-04-04 | 1974-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-10-03 | 1978-04-04 | 1978-10-04 | $7700.00 | Window Closed / Lapsed |