TECHNET Archives

November 2008

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Graham Naisbitt <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Graham Naisbitt <[log in to unmask]>
Date:
Mon, 10 Nov 2008 13:32:43 +0000
Content-Type:
text/plain
Parts/Attachments:
text/plain (117 lines)
Hi John

Yes!

The reason that no-clean fluxes pass old SIR tests is because they  
volatalize at temperatures ~>40DegC but the SIR used to call for  
85DegC/85%RH. If they are tested at 40DegC/90%RH as per the new SIR  
methods, you will probably see a different story. HP found that and  
reported on it - and many others also, but I am not sure they have  
published their problems.

No clean flux = very low or no solids = higher preheat = more  
absorbtion into a swollen laminate = possible electro-chemical  
reliability issues.

Lead-free = much higher process temperatures = a bigger problem?

Graham Naisbitt

On 9 Nov 2008, at 15:32, John Goulet wrote:

> Is there any information on products with No-Clean flux being  
> effected by moisture over a period longer than that tested in SIR  
> tests with the SIR comb test coupons? Some customers make products  
> for vehicles and toys that are subject to more humid conditions. The  
> No-Clean fluxes used always pass SIR which have high resistance  
> values even after 196 hours. However  if the humidity levels rise  
> and fall but never to the point of drying out the moisture. I  
> thinking that the humid spring and summer months could be a problem  
> if not sprayed with a conformal coat. The other situation I'm  
> testing is when a moisture sensitive part is used. Tests on three of  
> the boards showed that the moisture sensitive part was dragging the  
> surface insulation down. When I localized the heating to this part  
> with a small Leister heat gun, the resistance across the battery  
> terminals with the battery removed went back to infinity. Usually  
> the moisture sensitivity is a factor relative to the SMT reflow proc!
> ess and
> not an issue in operation. Any info on this? PS this batch was the  
> first ones using Pb-Free solder paste and that means I'll have to  
> check if the BOM changed to a different RoHs version of this special  
> moisture sensitive part.
>
>
> -------------- Original message --------------
> From: John Burke <[log in to unmask]>
>
>> FYI Werner has developed an Accelerated reliability model for  
>> SAC405/305
>> solder joint creep-fatigue. Details below
>>
>>
>> John Burke
>>
>> (408) 515 4992
>>
>>
>> -----Original Message-----
>> From: Leadfree [mailto:[log in to unmask]] On Behalf Of Werner  
>> Engelmaier /*
>> Sent: Friday, November 07, 2008 2:15 PM
>> To: [log in to unmask]
>> Subject: [LF] Accelerated reliability model for SAC405/305 solder  
>> joint
>> creep-fatigue
>>
>> Hi all,
>> Just to let everybody know, I have developed a creep-fatigue model  
>> for
>> SAC405/305 solder joints. It will be published in a presentation at  
>> the
>> IPC/JEDEC
>> Conference on Transitioning to Lead-Free: Strategies for  
>> Implementation on
>> December 8 to 10, 2008 in Dallas, TX.
>>
>> ---------------------------------------------------
>> 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
>> -----------------------------------------------------
>
> ---------------------------------------------------
> 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
> -----------------------------------------------------

---------------------------------------------------
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
-----------------------------------------------------

ATOM RSS1 RSS2