Browse Prior Art Database

Paste Tack Measuring Equipment

IP.com Disclosure Number: IPCOM000111313D
Original Publication Date: 1994-Feb-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 59K

Publishing Venue

IBM

Related People

French, W: AUTHOR [+3]

Abstract

Disclosed is an improved measuring equipment for the production line which simulates the G-forces experienced during practical material handling of a printed circuit board (PCB). The test is a controlled mechanical shock to a captive PCB to test the adhesive strength (tack) of solder paste securing SMT components to the PCB.

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This is the abbreviated version, containing approximately 64% of the total text.

Paste Tack Measuring Equipment

      Disclosed is an improved measuring equipment for the production
line which simulates the G-forces experienced during practical
material handling of a printed circuit board (PCB).   The test is a
controlled mechanical shock to a captive PCB to test the adhesive
strength (tack) of solder paste securing SMT components to the PCB.

      Previous methods of assessing tack by withdrawing an adhering
probe from the paste and noting tension holding-strength is
inconsistent and not an accurate analysis of what is happening
throughout the manufacturing process and all over the card.

      Solder paste tack is a critical property which is difficult to
measure and relate to production line performance.  Standard methods
involve retracting a probe from the printed deposit of solder paste
and measuring the holding force as the probe is retracted.  This
equipment in-house has been found to be totally unrepresentative of
Line Performance.  A developed and tried new approach to determining
paste tack which has thus far found to be wholly representative of
the product is simply a table on which a printed and placed PCB is
laid.   An accelerometer  is attached to the PCB, and an impulse is
applied to the PCB, giving it an acceleration.  The impulse (force)
applied is controlled by a hammer trigger and spring mechanism.   The
equipment has been built and used up to tack strength failure points.

      An embodiment of this equip...