Steve,
Just curious...is this the 35mm package with the big heat slug on the back?
We place alot of the 'C6201 & 'C6701 parts. We had tried them with a
Glenbrook unit and had the same results...very dark and barely able to make
out the balls. In looking at x-ray units to purchase recently, I had several
of the vendors x-ray these parts to see what the penetration was like. It
seems that we needed 90-100Kv minimum to get a decent picture. Glenbrook
can't get there.
On a related note, if you are placing the heavy heat-sinked part, did you
have a problem with the balls collapsing too much under the weight? That's
a problem we've had since TI switched to this packaging. We end up having
to 'shim' the parts to get enough standoff distance. Just curious, as we're
still searching for an efficient way to place and reflow these.
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 Stephen R. Gregory
Sent: Friday, April 28, 2000 9:20 AM
To: [log in to unmask]
Subject: [TN] I can't X-ray through this BGA!!!
Hi ya'll!
Well, we just fired up the line this morning on a job we've ran before, and
it's got a BGA on it. This time though, we're using a new Texas Instruments
DSP (PN# TMS320C620GJC200) because the one that was used last time is
obsolete.
Well, when the first board came off the machines, I went to verify placement
with the Glenbrook x-ray we have, and I could barely see through the part!
If
I turn the gain up to maximum, I can barely make out the balls, but I can't
see anything that tells me if I'm on the pads...
Has anybody ever run into this before? What do you do in a situation like
this? The placement looks good in relationship to the silkscreen outline of
the part...but I know I shouldn't depend on the silkscreen. But what else
can
I do?
Fun stuff...
-Steve Gregory-
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