US5045117A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System for removing flux residues from printed wiring assemblies
Assignee: Boeing North American Inc
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Filing: 1990-09-18
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Granted: 1991-09-03
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Expires: 2010-09-18
Abstract
Abstract A method and apparatus are provided for cleaning rosin flux residues off of printed wiring assemblies. In accordance with the invention printed wiring assemblies are placed within a processing chamber and a vacuum pump is used to draw a vacuum within the processing chamber. The rosin flux residues are then washed off of the printed wiring assemblies using a solvent for dissolving and removing the flux residues.
Inventors
- 👤 Donald R. Witherell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:27
CPC Classifications
C; C23; C23G; C23G5/00; C23G5/02; C23G5/04; B; B08; B08B; B08B3/00; B08B3/04; B08B3/08; H; H05; H05K; H05K3/00; H05K3/22; H05K3/26; H05K2203/00; H05K2203/07; H05K2203/0779; H05K2203/0783; H05K2203/08; H05K2203/085; H05K2203/15; H05K2203/1509
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
107 words
A process for cleaning rosin flux residues from printed wiring assemblies, comprising the steps of: placing one or more printed wiring assemblies in a vacuum sealable processing chamber; drawing down the ambient pressure within said chamber to achieve a partial vacuum in order to promote the migration of flux residues out of confined spaces on said assemblies; washing said wiring assemblies with solvent to remove flux residues which have migrated out of confined spaces on said assemblies; and drawing down the ambient pressure within said chamber to achieve a partial vacuum for a second time in order to evacuate any remaining solvent materials from on said assemblies.
Claim 2
Dependent Claim
107 words
A process for cleaning rosin flux residues from printed wiring assemblies, comprising the steps of: placing one or more printed wiring assemblies in a vacuum sealable processing chamber; drawing down the ambient pressure within said chamber to achieve a partial vacuum in order to promote the migration of flux residues out of confined spaces on said assemblies; washing said wiring assemblies with solvent to remove flux residues which have migrated out of confined spaces on said assemblies; and drawing down the ambient pressure within said chamber to achieve a partial vacuum for a second time in order to evacuate any remaining solvent materials from on said assemblies.
Claim 3
Dependent Claim
33 words
The process of claim 1, wherein the step of washing said wiring assemblies includes the substeps of: flooding said chamber with solvent, flushing solvent through said chamber, and purging said chamber of solvent.
Claim 4
Dependent Claim
14 words
The process of claim 1, wherein said partial vacuums approach 1 mm of Mercury.
Claim 5
Dependent Claim
33 words
The process of claim 1, wherein said steps of drawing down the pressure in said chamber include the substep of: collecting vapor phase solvent drawn out of said chamber in a cold trap.
Claim 6
Independent Claim
87 words
A system for cleaning rosin flux residues from printed wiring assemblies, comprising: a sealable processing chamber adapted for holding a plurality of wiring assemblies and for maintaining a partial vacuum during processing operations; vacuum pump means for drawing down the ambient pressure within said chamber in order to promote the migration of flux residues out of confined spaces on said wiring assemblies; and means for washing said assemblies with solvent in order to remove flux residues which have migrated out of confined spaces on said wiring assemblies.
Claim 7
Independent Claim
87 words
A system for cleaning rosin flux residues from printed wiring assemblies, comprising: a sealable processing chamber adapted for holding a plurality of wiring assemblies and for maintaining a partial vacuum during processing operations; vacuum pump means for drawing down the ambient pressure within said chamber in order to promote the migration of flux residues out of confined spaces on said wiring assemblies; and means for washing said assemblies with solvent in order to remove flux residues which have migrated out of confined spaces on said wiring assemblies.
Claim 8
Dependent Claim
25 words
The system of claim 5, wherein said means for washing includes: means for flooding solvent into said chamber and purging solvent out of said chamber.
Claim 9
Dependent Claim
30 words
The system of claim 6, wherein said means for flooding and purging solvent includes one or more liquid phase pumps which are further operative for flushing solvent through said chamber.
Claim 10
Dependent Claim
24 words
The system of claim 5 further including: a cold trap for collecting vapor phase solvent pumped out of said chamber during vacuum pump operations.
Claim 11
Dependent Claim
87 words
A process for cleaning rosin flux residues from printed wiring assemblies having SMDs installed thereon, comprising the steps of: placing one or more wiring assemblies in a vacuum sealable processing chamber; drawing down the ambient pressure within said chamber by pumping air out of said chamber with a vacuum pump in order to promote the migration of flux residues out from under the SMDs installed on said assemblies; washing said wiring assemblies with solvent to remove the flux residues which have migrated out from under the SMDs.
Claim 12
Dependent Claim
87 words
A process for cleaning rosin flux residues from printed wiring assemblies having SMDs installed thereon, comprising the steps of: placing one or more wiring assemblies in a vacuum sealable processing chamber; drawing down the ambient pressure within said chamber by pumping air out of said chamber with a vacuum pump in order to promote the migration of flux residues out from under the SMDs installed on said assemblies; washing said wiring assemblies with solvent to remove the flux residues which have migrated out from under the SMDs.
Claim 13
Dependent Claim
41 words
The process of claim 9, further including the step of: drawing down the ambient pressure within said chamber by pumping air out of said chamber for a second time in order to evacuate any remaining solvent materials from on said assemblies.
Claim 14
Dependent Claim
33 words
The process of claim 9, wherein the step of washing said wiring assemblies includes the substeps of: flooding said chamber with solvent, flushing solvent through said chamber, and purging said chamber of solvent.
Claim 15
Dependent Claim
24 words
The process of claim 9, wherein the ambient pressure within said chamber is drawn down to a partial vacuum approaching 1 mm of Mercury.
Claim 16
Dependent Claim
33 words
The process of claim 12, wherein said steps of drawing down the pressure within said chamber include the substep of: collecting vapor phase solvent pumped out of said chamber in a cold trap.
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) | 1994-09-02 | 1995-03-04 | 1995-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-02 | 1999-03-04 | 1999-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-09-02 | 2003-03-04 | 2003-09-03 | $7700.00 | Window Closed / Lapsed |