Hi Guys Could you give me the standard criteria that is being followed for solder ball in PCBA. I am aware that we have an IPC standard but still that is generic in nature. I need a one that is applicable for automotive industry.
Solder ball acceptance: IPC-A-610, 126.96.36.199 & 12.4.10. Solder balls: 5 ball system: * No more than 5 balls per square inch (100mm2) allowed * Solder balls can not be greater than 5 mil (0.005in) (100um) * Solder balls cannot be less than 5 mil (100um) from the nearest land or trace
We doubt the above references the latest and greatest A-610 verson, but who cares?
I work for one of the largest automotive suppliers. Our Workmanship Standards pre-date IPC-610 but they are nearly identical in regards to solder balls. We supply to all the major OEMs, including the Japanese, and I don't recall our solder ball standard ever being questioned.
According to 188.8.131.52, it states that defected if Solder balls are not entrapped in no-clean residue or conformal coating. How do you define entrapment or how do you assess if the balls won't dislodge under normal product service environment? The solder ball is attached to no-clean flux and it does not fall off with brush sweeping. I found difficulty to determine whether the solder ball will dislodge. Can anyone opinion whether it's defective or acceptable based on the photo?