Browse Prior Art Database

SMT Circuit Board Solder Joint Stress-Inducing Test Assembly

IP.com Disclosure Number: IPCOM000107204D
Original Publication Date: 1992-Jan-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 79K

Publishing Venue

IBM

Related People

Barnett, B: AUTHOR [+3]

Abstract

This article describes an assembly that induces solder joint stress on Surface Mount Technology (SMT) boards. This is accomplished by directly applying pressure to the solder joints via a pneumatic piston array. Solder joints having latent (pressure contact opens due to poor coplanarity of component pins or minute cracks internal to solder joint) defects will fail to provide good electrical contact under the direct application of pressure to the joint. The assembly provides the capability to attach power and input/output (I/O) connections so that functional tests can be run concurrently. The coincidence of the application of pressure to a joint and a test failure indicates that a latent defect has been identified. The assembly allows visual inspection of the solder joints under test.

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This is the abbreviated version, containing approximately 58% of the total text.

SMT Circuit Board Solder Joint Stress-Inducing Test Assembly

      This article describes an assembly that induces solder joint
stress on Surface Mount Technology (SMT)  boards.  This is
accomplished by directly applying pressure to the solder joints via a
pneumatic piston array.  Solder joints having latent (pressure
contact opens due to poor coplanarity of component pins or minute
cracks internal to solder joint) defects will fail to provide good
electrical contact under the direct application of pressure to the
joint.  The assembly provides the capability to attach power and
input/output (I/O) connections so that functional tests can be run
concurrently.  The coincidence of the application of pressure to a
joint and a test failure indicates that a latent defect has been
identified.  The assembly allows visual inspection of the solder
joints under test.

      The pneumatic piston array is attached to the base. The
location of the pistons in the array is chosen by the user to contact
the solder joints of interest.  The plexiglas cover of the assembly
is used to hold the circuit board in position over the piston array
(the clear cover allows visual inspection of the solder joints under
test). The pistons are soft-tipped to prevent damage to the circuit
board and will contact it from the bottom.  The PCB is held on the
base (component side up) by pressure pads mounted under the cover.
The pressure pads are mounted to constrain PCB vertical deflection to
the...