You are correct, perhaps I was too hasty in my answer. I have purposely failed SIR tests for certain fluxes due to their propensity to grow dendrites where I purposely left the flux residues on to simulate worst case conditions. I have never seen a failure due to the ability of the flux to be washed away in the cleaning process however. When we solder the test coupon, we use the very fine .005" spacing pattern, and if slightly too much solder is applied such that the gap between traces is reduced to less than .003", you will get a resistance reading too low at some point during the humidity cycling (due to the moisture condensation), even though there is no residue whatsoever present. These are the ones I exclude, because the reading was not due to any growth or presence of flux. Did I say that correctly?
-----Original Message-----
From: Bev Christian [mailto:[log in to unmask]]
Sent: Thursday, October 14, 2010 2:13 PM
To: Stadem, Richard D.; TechNet E-Mail Forum
Subject: RE: Interpretation of SIR Requirements
Richard,
I am surprised to hear that you "seldom pass a SIR qualification otherwise" using the Telcordia spec for SIR, because at Nortel we used Telcordia (or Bellcore for us old guys) and even set a higher resistance cut-off and used an IPA/toluene mixture to pull stuff into solution to put on the coupons and we passed most stuff. BUT that was using an average.
Bev
-----Original Message-----
From: Stadem, Richard D. [mailto:[log in to unmask]]
Sent: Thursday, October 14, 2010 2:39 PM
To: TechNet E-Mail Forum; Bev Christian
Subject: RE: Interpretation of SIR Requirements
I use a running average, and any failures I document as to why. For example, if there was a portion of the comb pattern that has excess solder that caused a lower than average reading, or even a reading less than the minimum required, but there was no evidence of any flux residue, dendritic growth, etc, as a result of failure to clean, then I discount or exclude that particular reading and note it on the qualification document. Strictly going by the Telcordia requirements, I would seldom pass a SIR qualification otherwise.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bev Christian
Sent: Thursday, October 14, 2010 1:30 PM
To: [log in to unmask]
Subject: [TN] Interpretation of SIR Requirements
TechNetters,
In GR-78-CORE, Issue 1, 1997, SIR Test Procedure 13.1.3.2 R13-6 [808], it states (capitalization mine) "The average insulation resistance (megohms), for EACH SAMPLE GROUP, taken at 24 hours and again at 4 days, shall be greater than the minimum specified in table 13-4.
In IPC J-STD-004B, 3.4.1.4.1 Reporting SIR Test Results, the first criteria for passing the SIR test is: "All SIR measurements on all test patterns shall exceed the 100 Mohm requirements."
My questions are as follows:
1) In the Telecordia document, what constitutes a "sample group"? One comb pattern? All the comb patterns on one coupon? All the coupons being used to test one material?
2) For the IPC method does the criteria apply to the readings at the end of the test? First and last? At every measurement? The document seems vague to me.
Bev
RIM
---------------------------------------------------------------------
This transmission (including any attachments) may contain confidential information, privileged material (including material protected by the solicitor-client or other applicable privileges), or constitute non-public information. Any use of this information by anyone other than the intended recipient is prohibited. If you have received this transmission in error, please immediately reply to the sender and delete this information from your system. Use, dissemination, distribution, or reproduction of this transmission by unintended recipients is not authorized and may be unlawful.
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------
---------------------------------------------------------------------
This transmission (including any attachments) may contain confidential information, privileged material (including material protected by the solicitor-client or other applicable privileges), or constitute non-public information. Any use of this information by anyone other than the intended recipient is prohibited. If you have received this transmission in error, please immediately reply to the sender and delete this information from your system. Use, dissemination, distribution, or reproduction of this transmission by unintended recipients is not authorized and may be unlawful.
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------
|
