Missing solder point on pcba assembly. 3

[mooimooi]

Hi there!

Need a bit of some guidance from pcba assly gurus;
You see, I have double sided pcb and on this i mount only the following components.
a) resistors - 3 pieces , total 6 solder points.
b) Photo interruptors - 3 pieces, total 12 points.
c) Hook up wires - 12 points

In total I have 30 points to manually solder. After solder,I go through a functional test. The functional test will also "pass" the points that were missed out during manual solder. This is because the component lead still makes contact with the pth(plated through hole) conductor.

Is there any simple way to check effectively whether all the 30 points have been soldered?

I tried using connection tester that detects resistance in the order of 0.4 ohm to 4 ohm, but am not very successful.

Another option is to make a template to check the 30 points, but this too can cause escapee to go through as we know that 100% visual inspection is at best 80% effective.

Another expensive way is probably using PRS ( Pattern recognition system ) , but such systems are beyond my means to buy.

Would appreciate anyone out there can provide some simple solutions to this simple problem. I am not too sure whether this is a simple problem or not!

Thanks and Regards

 

[BrianR]

Markls8,
My experience has been with military areospace equipment and the failures that occurred in equipment fitted to high performance aircraft. I was referring to the practice of oversoldering a dubious joint to "fix it up". The problem generally arose when a joint was not properly wetted with the solder because it wasn't properly cleaned, there was a build-up of rosin or the component drew a lot of heat and it didn't get hot enough. A dry joint would result and resoldering would not correct this but would bury it.

I agree with you though, that if you remove the old solder, eg with a vacuum desolderer, clean and resolder it, there is no problem, but I have seen many instances where a bad joint was resoldered without stripping and cleaning only to fail a bit later.

 

[Chuckles159]

If you're building 5K boards a day, wave solder them. You're doing 150,000 joints a day and that's worth an investment in wave soldering. A small wave soldering machine will pay for itself in 2 weeks at that throughput. We wave solder any batch of over 4 boards because the problems with inconsistent joints is just too risky.