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Capillary Flow Monitor for Encapsulants

IP.com Disclosure Number: IPCOM000122603D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Busacco, RA: AUTHOR [+6]

Abstract

A flow test to quantify the flow of low viscosity encapsulants through a small gap is disclosed. As shown in Fig. 1, the test apparatus essentially consists of a lower glass plate and a top glass plate with a groove typically 2-3 mils deep and 0.5" wide. The groove faces the lower plate, thus constituting a 0.5"-wide capillary of rectangular cross-section. These plates are mounted on a metal fixture. A scale is mounted adjacent the capillary. A fine-gauge thermocouple is attached to the lower plate.

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Capillary Flow Monitor for Encapsulants

      A flow test to quantify the flow of low viscosity
encapsulants through a small gap is disclosed.  As shown in Fig. 1,
the test apparatus essentially consists of a lower glass plate and a
top glass plate with a groove typically 2-3 mils deep and 0.5" wide.
The groove faces the lower plate, thus constituting a 0.5"-wide
capillary of rectangular cross-section.  These plates are mounted on
a metal fixture.  A scale is mounted adjacent the capillary. A
fine-gauge thermocouple is attached to the lower plate.

      The metal fixture is kept at the temperature at which the test
is to be performed.  A fixed amount of encapsulant is dispensed at
the edge of the capillary, and the encapsulant then flows into the
capillary.  The distance of the front of the encapsulant from the
edge of the capillary is measured as a function of time and plotted.
The nature of these curves provides the flow characteristics of the
encapsulant in small gaps.  Fig. 2 shows some typical curves.

      In place of the plane bottom plate and the grooved top plate,
two plane plates separated by an appropriately designed metal shim
can be used to form the capillary.  The test may also be used for
flow along surfaces of materials other than glass by making the
capillary out of those materials.