Browse Prior Art Database

Method for Simultaneously Screening Multiple Cut Cards with Single Stencil

IP.com Disclosure Number: IPCOM000119075D
Original Publication Date: 1997-Nov-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Barlow, SA: AUTHOR [+2]

Abstract

Disclosed is a method for accurately depositing solder paste on multiple printed circuit cards simultaneously using a single stencil.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 60% of the total text.

Method for Simultaneously Screening Multiple Cut Cards with Single
Stencil

      Disclosed is a method for accurately depositing solder paste on
multiple printed circuit cards simultaneously using a single stencil.

      With the implementation of transportable screener support
plates (*), the use of an accurate measuring system, and some
statistical analysis, a method has been developed to deliver multiple
cut cards to a  reproducible location within the screener apparatus.

This allows a design methodology to create a solder paste stencil
which allows multiple cut cards to be screened simultaneously and
accurately.

      A plate is designed and fabricated which holds the cards in
repeatable locations relative to each other.

      Once the plates are fabricated, a population of raw cards from
different manufacturing lots are placed in the plate pockets, and a
reference point on one card is chosen.  From that reference point, X
and Y measurements to at least one other feature on the same card,
preferably at least the most extreme fiducial of the card from the
reference point, are taken to the required accuracy.  From the
reference point again, measurements to the same degree of accuracy
are taken to a  minimum of two locations on each other card,
preferably extreme card fiducials.  The necessary raw card population
size will be dependent on  the finest pitch component on the raw
card.  The general guideline is to  use a random population such that
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