Alejandro,
        See IPC-A-610B Section 10.1, or IPC-A-610C Section 12.1. They
address adhesive encroachment into the finished joint, rather than at the
dispensing/printing operation. The Target/Process Indicator/Defect
requirements are different depending on which revision you are building to.
However, they both allow a fairly wide latitude as to how much can be there.
This should allow you to temporarily build product while you make
adjustments to your stencil design to eliminate the condition permanently.

Mike McMonagle
Senior SMT Engineer
Telxon Corporation
(713) 307-2443 Phone
(713) 307-2581 Fax
www.telxon.com

' Innovative Solutions for
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-----Original Message-----
From: Becerra Alejandro [mailto:[log in to unmask]]
Sent: Thursday, July 13, 2000 9:25 AM
To: [log in to unmask]
Subject: [TN] Adhesive over pads.


Hi to all,

We are testing stencil-printing process for adhesive dispensing in bottom
side for 0603 components.
We found that there are some adhesive dots that are touching the pads.
We found that the maximum distance that the dot penetrates the pad is
approximately 0.0025".
Is there any standard that defines if it is acceptable to have a small
quantity of adhesive over the pads?
Is there any thumb rule that indicates the size of the stencil aperture.
We have a 0.028" clearance between the pads, and an average dot size of
0.0225".

Thanks,




Alejandro Becerra
Phone (915) 841-8518, Fax (915) 841-8518
[log in to unmask]

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