Jim,
        I would be willing to help, but we need more information.  For example:

Did the operator of the screen printer change?
Are you using a new stencil?
Where are the solder balls after reflow?
Are you monitoring the reflow oven by recording profiles on a daily basis.  If so, did something change?
Are you using paste that is about to expire?
Is the operator cleaning the solder paste back into the jar and reusing it the next day?

You get the idea.  Let us know.

John Guy
ACI / EMPF
714 N. Senate Ave.
Indianapolis, IN 46202-3112
voice:  (317) 655-EMPF ext.130
fax:    (317) 655-3699
e-mail:         [log in to unmask]

-----Original Message-----
From:   Jim Mathis [SMTP:[log in to unmask]]
Sent:   Tuesday, October 07, 1997 2:45 PM
To:     [log in to unmask]
Subject:        [TECHNET] solderballs

Help!  We are experiencing solderballing during the reflowing of paste.
 What's causing it?  We've been reflowing for awhile and this is the first
time seeing this.  Obviously, something's different, but I don't know what it
is at this time.

Thanks for your help, all!

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