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A Wire Cutting Device With Constant Tensioner for Separating and Dispensing Thick Films

IP.com Disclosure Number: IPCOM000122058D
Original Publication Date: 1991-Oct-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 1 page(s) / 61K

Publishing Venue

IBM

Related People

Grau, P: AUTHOR [+4]

Abstract

A mechanism is disclosed that maintains constant tension on a very thin wire to provide a clean and reliable cut in a high volume dispensing operation.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 59% of the total text.

A Wire Cutting Device With Constant Tensioner for Separating and
Dispensing Thick Films

      A mechanism is disclosed that maintains constant tension on a
very thin wire to provide a clean and reliable cut in a high volume
dispensing operation.

      When dispensing thick films in a manufacturing mode, it is
necessary to separate the material accurately and repeatedly.  To
dispense thermal conductive paste onto back of module caps prior to
encapsulation, several different separation methods were evaluated,
and a thin (.003") stainless steel wire was chosen to provide the
paste cut. The wire is strung between the fingers of a two-pronged
steel fork.  When actuated, the fork slides across the column of
paste, and the wire cuts through the paste, separating a small pad
from the paste being extruded from the dispense head.

      Precise setup is very important to this process. Positioning of
the wire below the dispense nozzle, speed of the wire cut, and
tension on the wire all affect the precision of the cutting
operation.  Maintaining tension on the wire is most difficult, since
the wire has a tendency to stretch after many dispense cycles.  Once
this occurred, the fork drags the wire through the column of paste,
causing excessive build-up on the dispense nozzle and cutting
mechanism.  This build-up results in deterioration quality of the
paste pattern and requires additional tool downtime to clean off the
excess paste.

      The problem of maintaining...