Browse Prior Art Database

Fluidized Abrasive Hole-Cleaning

IP.com Disclosure Number: IPCOM000099139D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-14
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Fey, EO: AUTHOR [+2]

Abstract

Disclosed is a new, dry process for cleaning holes in printed circuit boards. The process forcing small particles through the holes to effect cleaning.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 53% of the total text.

Fluidized Abrasive Hole-Cleaning

       Disclosed is a new, dry process for cleaning holes in
printed circuit boards.  The process forcing small particles through
the holes to effect cleaning.

      When printed circuit boards are drilled under standard the
resin softens and smears over the internal planes.  This smear must
be removed before plating to reliable electrical contact.  Drill
smear may be by a variety of wet chemical processes, but all of
suffer from various associated problems, such as hazardous material
and waste disposal.  Plasma avoid these problems but present other
drawbacks cost, performance and capability.  The recent use
fluoropolymer materials presents further challenges, these materials
are chemically inert.

      The disclosed process involves pneumatically forcing a powdered
abrasive through the drilled holes.  Abrasive of the particles
removes any drill smear and slightly the hole wall.  Any type of
abrasive can be used standard abrasives, such as silicon carbide and
oxide.  However, the preferred abrasive was found be hollow ceramic
microspheres.  The spherical shape superior fluidity which reduces
hole plugging in comparison to ordinary abrasives.  It is also that
the low density of the microspheres allows to obtain comparatively
higher velocities than abrasives, thus allowing them to be almost as
abrasively, despite the difference in particle  Microspheres with a
size distribution between 5 75 microns are preferred but...