Richard's recommendations, prebake them always, and very slow ramp rate 1°C
per second (again) Richard's advice for soaking type reflow are
prerequisite. 

The trick is to use two zones for reflow, one zone to control ramp up and
one zone to control ramp down. Exiting the convention controlled zones while
the part is in reflow produced unacceptable warp.

We had better results in an oven with very well controlled convention
pressure and even heat distribution within the reflow zones. 

It was not possible to do this part in a short oven or malfunctioning oven.
During the process of optimizing the oven for this part we discovered that
our OmniFlo 7 was malfunctioning. Once corrected we achieved good results
with both the Paragon 98 and OmniFlo.

It was not possible to rework this part in any of our BGA rework stations,
and we had many brands and types, Nothing had enough control to heat it
without warping.
 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier /*
Sent: Monday, January 07, 2008 4:07 PM
To: [log in to unmask]
Subject: Re: [TN] Warpage of components

Hi Guy,
What could you do to that profile to prevent the warpage of the Altera
Flex484?



Werner

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