Dave,
You probably need to have a heart-to-heart with Doug Pauls, Brian Ellis,
Laura Turbini, John Sohn or others. But here is my little bit.
Definitely find time to look into it, but it ain't cheap. You will need a
good chamber (>$15K) and measurement equipment (>$10K) and test coupons ($
depends on source, your relationship to said vendor, type of coupon,
quantity, etc.) That being said, SIR is cheaper than having stuff crap out
in the field.
I would not call it an alternative to ionic cleanliness, but the next leap
up. Ionic cleanliness only gives you one number and you don't know what
part is due to nasties like chloride and what part is due to weak organic
acids. So, no, there is not a broad correlation between SIR readings and
ug/sq. cm.
And, yes, if I were a medical implant customer I would always be concerned
about conductive contaminants!
With SIR you can test under different temperature and humidity conditions,
for different lengths of time, different voltage differences, different
spacings, you can test with or without solder mask, you can test different
pad finishes, and you can test without or without components placed over the
test patterns. You can test bare boards from the supplier, fluxes, solder
pastes, cored wires, SMT adhesives, tapes, labels, temporary solder masks,
lubricants, thread lockers, other adhesives, cleaners, flux inhibitors (used
where you don't want flux to go), cleaning processes, the effect of
different reflow profiles on residue chemistries, dramatically illustrate
poor handling techniques and so on. The testing is usually automated, so you
can get a lot of numbers (more numbers, more equipment, more $ though),
although, depending on the test, you are looking at 24 hours to 1000 hours
of testing.
That's a partial answer to your last question.
regards,
Bev Christian
Materials Lab Manager
Research in Motion
-----Original Message-----
From: Dave Kell [mailto:[log in to unmask]]
Sent: April 27, 2001 11:34 AM
To: [log in to unmask]
Subject: Re: [TN] SIR Definition
Thats for starting the conversation. I have been trying to find time to
look into SIR. Is it considered an alternative to ionic cleanliness? If so,
is there any correlation to ug/sq. cm. We have some medical implant
customers, that are concerned about any conductive surface contaminate.
What other benefits are available with SIR?
>>> [log in to unmask] 04/27/01 10:17AM >>>
OK, let's see what I can stir up today. :)
I am looking for a clear, succinct definition of surface insulation
resistance. If I look in IPC-9201 "Surface Insulation Resistance Handbook",
I don't find what I am looking for. (Sorry, Joe, Doug et al). What I find
on page 2, section 2.1, Definitions is the following: "It represents the
electrical resistance between two electrical conductors separated by some
dielectric material(s). This property is loosely based on the concept of
sheet resistance, (see ASTM-D-263), but also contains elements of bulk
conductivity, leakage through electrolytic contaminants, multiple dielectric
and metallization materials and air." Whew!
Any takers? Hmmm?
regards,
Bev Christian
Research in Motion
----------------------------------------------------------------------------
-----
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send the following message: SET
Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases >
E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
ext.5315
----------------------------------------------------------------------------
-----
----------------------------------------------------------------------------
-----
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send the following message: SET
Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases >
E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
ext.5315
----------------------------------------------------------------------------
-----
---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------
|
