Mario,

We use vision to place our BGA packages. However, I have seen people place
them by hand within an outline with good success. Also saw a video showing
BGA reflow very close-up. Parts placed up to 80% off the pads still centered
perfectly. They also placed parts 50% off the pads and tilted the board at
about 6 degrees. The BGAs still centered, 'pulling' themselves uphill so to
speak.  I suspect some of this depends on the size and weight of the BGA in
question. That wasn't mentioned.  However, I think it does point out that
the process can be pretty forgiving when it comes to placement.

Regards,
Rick Thompson
Ventura Electronics Assembly
2665A Park Center Dr.
Simi Valley, CA 93065

+1 (805) 584-9858 voice
+1 (805) 584-1529 fax
[log in to unmask]


-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Dion, Mario
Sent: Wednesday, February 16, 2000 5:31 PM
To: [log in to unmask]
Subject: [TN] BGA placement without ball inspection...


Bonjour Technet,

We plan to place BGA packages with our regular P & P equipment that is not
having the capability to inspect balls prior to place the component onto a
CCA. To do so, we will use the mechanical outline of the package and the P &
P vision system to place the BGA.

We however had the following information from one of our customer saying:

..." a variation in the distance between the edge and the first ball is
possible, and
difficult for the component manufacturers to control..." So it could be very
risky in terms of
reliability, quality and repeatability to use this mean to place a BGA onto
a CCA.

However we are aware that BGA packages exhibit excellent self-centering
properties so even if a slight variation exist from package edge and the
first ball this should not be a problem.

Is anybody else have a concern about that ? Please let me know a.s.a.p.

Thanks and Best Regards,

Mario Dion

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