Hey Bev,
I hope you are doing well. It depends on the repair method and whether
you want to save the components for FMA analysis. If you are going to
using a repair system (e.g. AirVac SRT, etc..) that concentrate the heat
into the PWB (FR4 in our case) then yes, you need to bake or you could
get delamination, blistering, or noticeable physical change in the
PWB/soldermask.
Also, if you want to do FMA on the components, and you can't or don't
want to cut the leads off, you have to treat it like the MSD that it is
and bake appropriately.
If it is a small device that you can remove with hand tools (Metcal or
Hakko type) then you are not going to get the PWB hot and therefore you
do not need to bake. I don't recommend using these tools if you want to
do FMA.
Call me on my cell if you want to talk directly. I am south of the
border in Guadalajara for the next few weeks.
Take care,
Russell Nowland
Alcatel-Lucent
Supply Base Engineer
Address: 14000 Quail Spring Parkway, Suite 300
Oklahoma City, OK 73134
email: [log in to unmask]
Desk: 405-302-1660
Cell: 405-203-0034
Fax: 405-302-1622
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bev Christian
Sent: Thursday, January 18, 2007 7:23 AM
To: [log in to unmask]
Subject: [TN] Rework of circuit packs with MSL Parts
Technetters,
We have required that circuit packs that are going to be reworked to be
dried before rework. My questions to all of you are:
1) Do you require this for all your boards irrespective of what is on
them?
2) Do you dry it to the requirements of the most sensitive MSL
component?
3) Do you use thermocouples to see how hot the MSL components are going
to get from radiated, convected and transmitted heat?
40 If the latter, what is the maximum temperature you allow the nearest
MSL component to reach before you require a pre-dry?
Thanks in advance.
Bev
RIM
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