Hi Brian!
I apologize for that seeming to be my intention. I very much agree with your statement. My only intention was to say that fielded reliability is a very big science, and difficult to do. Take one single test, like solder float or ANY of the others, and declare that if something passes the test it will be reliable in the field, and you will likely be embarrassed real soon!
Wayne
________________________________________
From: Brian Ellis [[log in to unmask]]
Sent: Monday, May 27, 2013 10:37 AM
To: TechNet E-Mail Forum; Wayne Thayer
Subject: Re: [TN] Difference berween solder float and solder dip
Whoa, Wayne. You are saying that the solderability of PCBs and
components has no influence on reliability; the reliability guys who
ignore this are simply not doing their job.
Brian
On 27.05.2013 17:19, Wayne Thayer wrote:
> Most others who respond to this group are much more versed in IPC standards than I am. I do know that when testing out layups it is common to implement an IPC solder float test where a sample is alternately floated on molten solder and then pulled off and allowed to cool for a certain number of cycles, like 3x to 5x. A nice thing about this test with through holes is that the solder usually wicks into the holes and supports the via barrel during cross sectioning. This is a stressful test, but doesn't resemble most usage conditions at all. Running the sample through the reflow process multiple times is much more similar to actual use. 5x reflow suggests a unit can take initial soldering plus a couple of rework cycles.
>
> IST is also a great technique for looking at board structure robustness, but it is expensive to get done and can only be done on a specially designed sample.
>
> While boards which do better on these tests are likely to last longer in the field, there is no simple or direct relationship from results to field life. To validate field life is another science.
>
> Solder wettabiity by dip testing is something the board assembler cares about, not the reliability guys.
>
> Wayne
> ________________________________
> From: SARAVANAN R [[log in to unmask]]
> Sent: Monday, May 27, 2013 8:22 AM
> To: TechNet E-Mail Forum; Wayne Thayer
> Subject: Re: [TN] Difference berween solder float and solder dip
>
> Dear Mr Wayne Thayer,
>
> Some hi reliability agencies asking for solder dip to test the robustness of the PTH and laminate integrity.
> But all the standards talk about solder float & reflow simulation.
>
> I am interested in knowing which is the robust test ?. What are the difference in stress that the specimen is undergoing the two tests?. regards,
>
> R.Saravanan
>
>
> ________________________________
> From: Wayne Thayer <[log in to unmask]>
> To: [log in to unmask]
> Sent: Sunday, 26 May 2013 11:27 PM
> Subject: Re: [TN] Difference berween solder float and solder dip
>
> Hi Inge-
>
> I'm confused! Is it possible you messed up 1&2? Testing wettability on components makes sense to me.
>
> I thought float was for seeing how robust the circuit board construction is, although the "popcorn" test was done on components years ago before people knew how dry components needed to be kept.
>
> Wayne
> ________________________________________
> From: TechNet [[log in to unmask]<mailto:[log in to unmask]>] on behalf of Inge Hernefjord [[log in to unmask]<mailto:[log in to unmask]>]
> Sent: Sunday, May 26, 2013 7:26 AM
> To: [log in to unmask]<mailto:[log in to unmask]>
> Subject: Re: [TN] Difference berween solder float and solder dip
>
> Hi Ramakrishnan,
>
> 1. Solder dip test tells about the WETTABILITY.
>
> 2. Floating test tells about the ALIGNMENT
>
> Typically 1. is performed on just a few coupons and NO components, while 2.
> is done with many coupons (or PCBs) and WITH components. For getting good
> statistics it's not unusual with 10,000 components.
>
> Inge
>
>
> On 25 May 2013 14:02, Ramakrishnan Saravanan <[log in to unmask]<mailto:[log in to unmask]>> wrote:
>
>> What is the difference between solder dip test and solder float test of
>> PWB test coupon. What is the difference in stress levels ?
>>
>> regards,
>>
>> R.Saravanan
>>
>
>
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud service.
> For more information please contact helpdesk at x2960 or [log in to unmask]<mailto:[log in to unmask]>
> ______________________________________________________________________
>
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud service.
> For more information please contact helpdesk at x2960 or [log in to unmask]<mailto:[log in to unmask]>
> ______________________________________________________________________
>
>
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud service.
> For more information please contact helpdesk at x2960 or [log in to unmask]
> ______________________________________________________________________
>
______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
|
