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Subject:
From:
Yuan-chia Joyce Koo <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Yuan-chia Joyce Koo <[log in to unmask]>
Date:
Fri, 6 Apr 2018 09:18:35 -0400
Content-Type:
text/plain
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text/plain (76 lines)
as I said before, the 20% is not universal  applicable.  you need to  
have data to back up why it is 20%... (for smaller  BGA, I would do  
10% max).  IMHO.
On Apr 6, 2018, at 8:55 AM, <[log in to unmask]>  
<[log in to unmask]> wrote:

> Dell - Internal Use - Confidential
>
> Joyce,
>
>    Is there supported documentation for the Post Sequential Test  
> allowable percentage (20% max.)?
>
> Victor,
>
> -----Original Message-----
> From: Yuan-chia Joyce Koo [mailto:[log in to unmask]]
> Sent: Friday, April 6, 2018 7:43 AM
> To: TechNet E-Mail Forum <[log in to unmask]>; Hernandez, Victor G  
> <[log in to unmask]>
> Subject: Re: [TN] FW: IPC-A-610G, section 5.2.9,, Solder anomalies- 
> Fractured solder, Defect 1, 2, 3 (Axial leaded device)
>
> at time zero - as out of factory - no fracture allowed - if you  
> have fracture at BGA solder mask area, you got crack initiation  
> site - you need to change solder mask openning to avoid such a  
> fault IMHO.
>
> At end of sequential test (vib, thermal shock, drop/impact), 20%  
> max.... Noted in qual report for review as item of susceptibility  
> of overall system design - program manager have to sign up for  
> knowingly accept the reliability risk.
>
> If it is go to sky or some places that repair and overhaul are not  
> allowed, you have to have redundancy exist to avoid potential  
> failure risk.  20% is based on electrical design and thermal design  
> requirements for device under overall assembly level design... not  
> cast in stone and not universal (23% was maximum based on FEM and  
> design assessment of worst case performance in this case to derive  
> to 20%, for example, max environmental temp plus assembly add on  
> operational temperature for signal current carrying capability and  
> thermal conduction capability - special attention to the power and  
> ground..etc.etc)... for example.
> hopefully, it helps.
> jk
> On Apr 6, 2018, at 6:53 AM, <[log in to unmask]> wrote:
>
>> Fellow TechNetters:
>>
>>    I was surprised that very little input was provided.
>> Therefore, since it Friday Elements QUIZ day. I will take  
>> advantage of
>> the high volume traffic day.
>>
>> Victor,
>>
>> From: Hernandez, Victor G
>> Sent: Thursday, April 5, 2018 10:22 AM
>> To: TechNet E-Mail Forum <[log in to unmask]>
>> Cc: Hernandez, Victor G <[log in to unmask]>
>> Subject: IPC-A-610G, section 5.2.9,, Solder anomalies-Fractured
>> solder, Defect 1, 2, 3 (Axial leaded device)
>>
>> Fellow TechNetters:
>>
>>    Is there a percentage associated with the statement "Fractured
>> Solder" in the above stated IPC STD section?
>> I did not a similar statement, Fractured Solder, for Surface Mount
>> Devices and Surface Mount Area.
>> Is there an acceptable percentage of the solder joint lead interface
>> that can be fractured?
>>
>>
>> Victor,
>

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