Hi everybody,
        Two week ago, we got a big problem of BGA that do not work after the
rework.  Almost all BGA fail after the rework.
THe BGA is a 27mm x 27mm standard BGA,.  We have two reworks machine, an
air-vac DRS24 and air-vac DRS22.  The problem only occur on the DRS24, which
is the newest machine !  We modify the profil to lower the temperature, but
my problem is that when i reach around 215 C in the join of the bga, the top
of the bga body is around 235C, which is more than the recommanded
temperature for BGA by the manufacturer.

The profil we use is like :     preheat : 2 min at 60% of the flow and 250 C
 the join reach around 165 C)
                                        soak : 1 min at 50% of the flow and 290 C   ( the join reach around 180
C )
                                        ramp : 1.5 min at 60% of the flow and 330 C  ( the join reach around
215 C )

The BGA are keep in a dry cabinet to redust moisture

Does is seem good ?  I not sure of the balance between longer time and lower
temperaturer versus shorter time and hotter temperature. Anyone have
experience with this.  Also, when you mesure the temperature, which ball you
use : the inner or the outter ? The inner ball seem to be more hot than the
other one. Also, for the people who have air-vac machine DRS22 and DRS24,
have you problem of stability with the DRS24, compare to the old DRS22.

Thank you.

Julien Bouchard
Matrox - Process Engineer

---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------