Browse Prior Art Database

ULTRASONIC FLUX FREE WAVE SOLDERING SYSTEM

IP.com Disclosure Number: IPCOM000006073D
Original Publication Date: 1991-Apr-01
Included in the Prior Art Database: 2001-Nov-30
Document File: 2 page(s) / 73K

Publishing Venue

Motorola

Related People

Richard L. Wendt: AUTHOR

Abstract

CFC (Chlorofluorocarbon) solvents must be eliminated to prevent damage to the earth's ozone layer. Elimination of all solder fluxes from the soldering process eliminates the need to clean a soldered printed circuit board (PCB) with CFC solvents to prevent the possibility of leaving ionic contamination on the PCB. Thus eliminating the need for solder flux will reduce usage of CFC solvents.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 58% of the total text.

Page 1 of 2

0 M

MOTOROLA INC. Technical Developments Volume 12 April 1991

ULTRASONIC FLUX FREE ~ WAVE SOLDERING SYSTEM

by Richard L. Wendt

  CFC (Chlorofluorocarbon) solvents must be eliminated to prevent damage to the earth's ozone layer. Elimination of all solder fluxes from the soldering process eliminates the need to clean a soldered printed circuit board (PCB) with CFC solvents to prevent the possibility of leaving ionic contamination on the PCB. Thus eliminating the need for solder flux will reduce usage of CFC solvents.

  The present proposed system produces a myriad of tiny molten solder spheres which impact the area to be soldered on PCB and chip away at oxides and other contaminates until the PCB conductors to be soldered are clean. Bare metal is thus exposed and the solder wets to it without the use of solder flux. This is similar to the cavitation cleaning action in bath type ultrasonic systems. The system may be operated in several different modes. Under an inert gas blanket, the spheres will be pure solder without oxidation. Operation in a normal atmosphere will produce a thin shell of lead and tin oxides. As these shells crash into the work area, they will crack up, abrading the work area to clean it and splattering molten solder to make the connection. Alternatively, an abrasive material

could be suspended in the solder which would abrade the surface as the solder spheres impact.

The equipment consi$ts of a molten solder source
(I), a solder pump (2), a modulator...