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Post Solder Cleaning Process for High Voltage Power Supplies

IP.com Disclosure Number: IPCOM000077383D
Original Publication Date: 1972-Jul-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Anschel, M: AUTHOR

Abstract

Product pieces having surface contaminants require cleaning before encapsulation, to assure adhesion and proper curing of the encapsulating potting system, as well as to prevent potential arcing. One example of such contaminants is polymerized solder flux residue, which often contains detrimental conductive and corrosive amine hydrochloride salts as activating agents, in addition to rosin and by-products of rosin which have outgassing potential. Potting material such as the silicone resin systems, which have poor adhesive qualities in general, will not adhere to residual flux nor will it cure to the polymeric material properties desired.

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Post Solder Cleaning Process for High Voltage Power Supplies

Product pieces having surface contaminants require cleaning before encapsulation, to assure adhesion and proper curing of the encapsulating potting system, as well as to prevent potential arcing. One example of such contaminants is polymerized solder flux residue, which often contains detrimental conductive and corrosive amine hydrochloride salts as activating agents, in addition to rosin and by-products of rosin which have outgassing potential. Potting material such as the silicone resin systems, which have poor adhesive qualities in general, will not adhere to residual flux nor will it cure to the polymeric material properties desired.

The component to be potted may itself be a source of surface contaminants. Nonpolar plasticizers from the component material and halogenated polymer degradation products formed from the component and a cleaning solvent are examples.

In view of the importance of cleaning the product piece thoroughly, and at the same time avoiding introduction of new surface contaminants, the cleaning procedure should utilize as stable a solvent as possible for the cleaning action required, employ mechanical cleaning action to enable minimization of time and temperature of the cleaning steps, and employ rinses in clean solvent of increasing stability.

For example, a cleaning procedure for a populated printed-circuit board may be as follows: Step 1) The soldered underside of the P/C board...