Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


solder on gold finger

edylc

#5947

solder on gold finger | 13 April, 2001

Hi,

Anybody can enlighten me where does this solder on gold finger came from...... A brief details on our process >>>> gold finger was covered by a Kapton tape and it was done offline away from the Screen printer or rather from the SMT lines itself, we are using an ENIG Pcb's , the process doesnt need a wave soldering ....however at the final end of the line , where visual inspection is perform a lot of solder on gold finger appears as a dot which can be seen by a 10X scope. I cant figure out where does this come from ...

reply »

Dave G

#5948

solder on gold finger | 13 April, 2001

Just a guess--

Could you be seeing the nickel under the gold plating because you are removing some of the Gold with the Kapton Tape ? This should be easy to verify. Otherwise it sounds like things are pretty much covered.

reply »

edylc

#5954

solder on gold finger | 13 April, 2001

Hi , Could you be seeing the nickel under the gold plating because you are removing some of the Gold with the Kapton Tape....?? You mean , the adhesive properties of the kapton tape will cause the gold plating on the gold finger to be somehow peel off , when the kapton tape was being removed ... One thing I've notice as well, even before the kapton tape was removed , thru a 10X scope I can see a small dot underneath the kapton tape, when it was verified with a 30X and the kapton tape was removed , it was a solder , Upfront , there is a visual inspection of the incoming PCB's but the DPPM is not that high compared at the Final end or the final visual inspection..

reply »

thrasher7

#5963

solder on gold finger | 16 April, 2001

How do you handle wipe-downs at screen print? This is often a culprit.

Just a thought..

reply »

edylc

#5980

solder on gold finger | 17 April, 2001

Hi Thrasher7, We called it wash boards, any misprint from screen printer was at tight control ..and those wash boards when being flow down to the line have an identifier /marker , is a matter on isolation of the problem..... But I still can't think of it where does it come from..... anyway thanks from for your thoughts....... Can someone share their idea as well...

reply »

#5995

solder on gold finger | 17 April, 2001

The issue is on the table. Which is it? Are you ...

* Loosing your gold plate when you remove the tape? [A tape test is a standard test for evaluating gold fingers. Check IPC-TM-650, test number wachacallit. Checkitaut.]

OR

* Putting tape over solder balls?

Is all of your solder on gold the same as you described?

reply »

3D SPI

SMT Replacement Nozzles