The PCBA will be assembled into housing with potting, and wires will be fixed well after assembly. 
Yes, the pad design need to be improved, such as that enlarge pad size to get more strength. But the PCB obviously have problem on some where.


 
RongJun Deng

-----Original Message-----
From: Tan Geok Ang [mailto:[log in to unmask]] 
Sent: Monday, October 12, 2015 10:21 AM
To: TechNet E-Mail Forum <[log in to unmask]>; Deng RongJun <[log in to unmask]>
Subject: RE: Solder joint peel off from ENIG board

First your pads design is not the same across the 3 points on the PCB, secondly the wire (high AWG) stressed the solder joints. 
Do tag/put adhesive/epoxy to hold the wires on the PCB so that the stress will be hold down at the epoxy area.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Deng RongJun
Sent: Friday, 9 October 2015 4:14 PM
To: [log in to unmask]
Subject: [TN] Solder joint peel off from ENIG board

Hi all:


I have got a solder joint strength issue on ENIG board, the cables soldered on board can be easily detach from pads by a small external force(1kg), the cable mounting process is hand soldering. Failure rate is about 20%.



We have made SEM and EDS test for solder joint and peel off surface, P Wt% is high than normal.  And we have also made SEM test for 10pcs bare board, the Au thickness is 0.038-0.05um, Ni thickness is 2.8-4.0um.



As I know high P Wt% will affect solder joint strength, what issue is happened during PCB fabrication process? Anybody know anything about this?

Here comes pictures:
http://pan.baidu.com/s/1sjl7Ynb

Best regards
Deng

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