Browse Prior Art Database

Method to Improve Solderability of the Leading Edge of Clark Composites

IP.com Disclosure Number: IPCOM000122065D
Original Publication Date: 1991-Oct-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 1 page(s) / 39K

Publishing Venue

IBM

Related People

Bonafino, EJ: AUTHOR [+3]

Abstract

Solder defects periodically occur on the leading edge of Clark type composites (approx. 1st six inches) during glycerine/EDTA immersion flux solder processing. The incorporation of a leading edge stabilizer plate on the board carrier fixture resolves many of the causes of leading edge defects. The purpose of the stabilizer plate is basically two-fold: 1. It changes the turbulent wave solder flow present at the leading edge of defective boards to a smooth laminar wave, similar to the laminar flow that the trailing edge of the board (which exhibits no solder defects). This allows sufficient time for the wave to stabilize, after the leading edge of the "fixture" has entered the wave. 2.

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Method to Improve Solderability of the Leading Edge of Clark Composites

      Solder defects periodically occur on the leading edge of Clark
type composites (approx. 1st six inches) during glycerine/EDTA
immersion flux solder processing.  The incorporation of a leading
edge stabilizer plate on the board carrier fixture resolves many of
the causes of leading edge defects.  The purpose of the stabilizer
plate is basically two-fold:
1.   It changes the turbulent wave solder flow present at the leading
edge of defective boards to a smooth laminar wave, similar to the
laminar flow that the trailing edge of the board (which exhibits no
solder defects).  This allows sufficient time for the wave to
stabilize, after the leading edge of the "fixture" has entered the
wave.
2.   It also increases the time that the wave solder actually
contacts the leading edge of the board, and drives out any gases
prior to the solder wave contacting those pth's, resulting in
elimination of that specific type of solder defect.  Basically, the
purpose of the modified fixture is to assure that the leading edge of
the board will behave the same as the trailing edge of the board -
which does not exhibit solder defects.

      Disclosed anonymously.