Browse Prior Art Database

Micro Screener

IP.com Disclosure Number: IPCOM000121942D
Original Publication Date: 1991-Oct-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 74K

Publishing Venue

IBM

Related People

Smith, T: AUTHOR [+2]

Abstract

The device disclosed is a small stencil screener. This screener is used for dispensing viscuous fluids and pastes used during the manufacture and assembly of printed circuit boards. This screener is most useful for extremely small or fine pitch, finely defined parts requiring great accuracy and consistency of fluids and paste applications.

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This is the abbreviated version, containing approximately 52% of the total text.

Micro Screener

      The device disclosed is a small stencil screener.  This
screener is used for dispensing viscuous fluids and pastes used
during the manufacture and assembly of printed circuit boards.  This
screener is most useful for extremely small or fine pitch, finely
defined parts requiring great accuracy and consistency of fluids and
paste applications.

      The large size of some printed circuit boards forces the
dimensional tolerances and locations of the very small, fine pitch
components beyond the capabilities of standard full coverage
screeners used in high yield processes.  The full coverage screeners
also dictate the use of a single paste screened onto the entire
surface of the circuit board surface.  The pastes most useful for
very small openings in the stencil are ideally different rheology and
costs than the pastes used for relatively large openings in a
stencil. The screener described in this article can minimize the
above constraints and maximize yields with high density, varied pitch
component screening needs.

      This device (see the figure) consists of 4 major parts: the
stencil/frame, the squeegee, the backup plate, and the camera/vision
positioning system.  The stencil is fabricated using using available
stencil materials and methods.  The stencil is optimized for a partic
ular component(s) requiring greater accuracy and consistency than a
full coverage screener can provide.  The thickness/contour of the
stencil/frame as well as the size of the openings can be optimized
for the desired paste/fluid as well as the component and...