Hi Al:
        Are you cleaning your boards in an inline cleaner?  Does the inline cleaner have two mesh chains? If that is the case, the mesh from top and bottom do not move at the same rate and get components hooked at the top and the bottom and shear them off. One solution of many is to have the boards inside cages. Another is to eliminate the top mesh.
        Regards,
        Ramon
	

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From: TechNet [mailto:[log in to unmask]]On Behalf Of
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Sent: Thursday, April 21, 2005 6:57 AM
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Subject: [TN] Optofet Relay Reliability


Technetters:

On a large board (16" x 20"), some optofet relays (4-pin SMT SSOP4
package) are being "knocked off" during post-reflow assembly, handling,
cleaning, or ??.

The relays are located on both sides of the board.  We mount temporary
standoffs on the board (during some of the manual assembly whenever
possible) to protect these and other parts, and have reduced the problem,
but would like to eliminate the problem.

Here's a link to manufacturers website to view the part:
http://www.aromat.com/pcsd/product/pmos/pdf_cat/aqy221n2v.pdf#search='aqy221n2vy'

We've added glue (chip bonder) dots to each side of the relay before
placement, but that may (or seems to) be lifting the part slightly causing
poor solder contact.


Some questions:

Are there IPC or industry specs. on the shear force a component should be
able to handle?

Would a post-reflow underfill work (the underside clearance is the height
of the solder, maybe about .003")?

Are other users of this part experiencing the same problem?


As usual, thanks in advance for your responses,


Al Kreplick
Sr. Mfg. Eng.
Teradyne, Inc.
500 Riverpark Drive
Mail Stop NR500 1-1
North Reading, MA 01864
Tel: 978-370-1726

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