Aric,
        One way to obtain consistent placement is to design a fixture
specifically for heat sink installation.  One design that I've seen has the
board held in place by tooling pins at the corners with board support at the
appropriate areas.  The board is placed on the fixture then a hinged arm is
swung down over the cpu area.  This arm has a hole at the end in the size
and shape of the heatsink to be placed.  When the arm is in place over the
cpu, the heatsink can be placed in the hole on top of the cpu, which ensures
consistent placement.  If necessary, this design will also work in
conjunction with a press to make sure it is seated well.




                I-----------------I
                I *                 *   I
                I            I---I      I +---I---I
                I            I   I      I +---I   I
                I            I---I      I     I---I
                I                       I
                I                       I
                I                       I
                I *                 *   I
                I-----------------I

        KEY to lame drawing above:
           * = tooling pin
         + = hinge for arm

        Hope this helps,
          Tom


-----Original Message-----
From: Aric Anderson [mailto:[log in to unmask]]
Sent: Monday, June 21, 1999 12:54 PM
To: [log in to unmask]
Subject: [TN] Heat Sink Assembly


Hello Technetters,

I am encountering several problems with a  heat sink assembly process.
Currently, our heat sinks are hand placed onto cpus and other components
using an epoxy dispenser ( automatic ) and a steady hand.

The Problem:  The heat sinks are not seating properly, misaligned and
uneven due to operator error.  Some of our products use clips and pins
for heat sink placement, but several do not.  I know that this is an
issue of board real estate that needs to be resolved between
manufacturing and engineering, but until then I am looking for a
solution.

I want to take the human factor out of this heat sink placement so I can
achieve the proper alignment and force to attach heat sinks to
components.  They are to large and cumbersome for any high speed
placement machine.


If anyone has experienced this problem and has any suggestions, your
response would be much appreciated.