Hi Wee Mei,

A1:  The safe answer - it depends.  If strong vibration is an environmental
concern then I would look into using either a staking compound (staying away
from silicone based adhesives to avoid primer & dewetting problems), tie
wrap or a mounting.

A2:  You can specify your own flatness requirements and don't need to be
restricted by the IPC standards.  You can still use IPC-TM-650 2.4.22 (as a
starting point if nothing else) to test for flatness even if the board isn't
a simple rectangle - flat is flat.

Hans

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Hans M. Hinners
Electronics Engineer
Warner Robins - Air Logistics Center (WR-ALC/LUGE)
226 Cochran Street
Robins AFB GA 31098-1622

mailto:[log in to unmask]

Com: (478) 926 - 5224
Fax:   (478) 926 - 4911
DSN Prefix: 468


-----Original Message-----
From: fullname [mailto:[log in to unmask]]
Sent: Wednesday, April 03, 2002 3:49 AM
To: [log in to unmask]
Subject: [TN] Single-sided board and warp


I have two main questions to ask :

Q1 : Single-sided board reliability.
- in the usual fabrication process, single sided board only have pads on
one side and the holes are not plated-through. What is the chances that
the component will fly off or pads lifted during vibration test?

- if everything remain but the hole wall is plated, will the solder
joint now be more robust to withstand vibration or the component will
stay put or pads will not be lifted?

Q2 : warpage
- I noticed that warpage indicated in the IPC standard usually are
confined to boards that are 4 sided. For my board, flatness is a must
but the board is of odd shape or irregular shape. How do I perform the
warp test and acceptance?

Regards - Wee Mei

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