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Testing assembled PCBs

Alexander , 04-11-2016, 03:14 AM

I look for PCB design recomendations for testing assembled PCB. I have found only one way - Test Pads (should be round SMT pads, either with a minimum diameter of 35 [mils] located on a 100 [mils] or 75 [mils] grid, or with a minimum diameter of 40 [mils] located on a 50 [mils] grid . Also they should have recommended IPC clearances to other objects).

My question is ,do I need add/know something more?What is most popular (result /money) technique for testing assembled HDI PCBs? It seems that this step is better discuss with manufacturer, but now I want to minimize Desing for Test process.

Thank you!

robertferanec , 04-12-2016, 02:08 AM
I am interested to hear some answers too.

In our case, we normally place all the testpoints on the bottom, so we could use a simple bed of nails. Clearance, size and grid is often problem as our boards are usually quite packed. In my previous job we used to design and manufacture the bed of nails in our company, we only asked someone to drill the holes.
Alexander , 04-13-2016, 09:20 AM
Thank you for your answer! It seems that bed of nails test more suitable for small volume production. As I understand the flying probe is using for mass production, am I right?
robertferanec , 04-13-2016, 09:23 AM
We have never used flying probe (so, I can not advice on this), but we did use bed of nails for quantities in thousands.
Alexander , 04-13-2016, 09:41 AM
Thank you! Can you recommend me copmany who may help with understanding PCB rules for simple bad of nails(DesignForTests) and product the fixture ? Anyway thanks a lot for you!
robertferanec , 04-15-2016, 05:52 AM
I don't really know any special company Maybe someone else reading this forum may know?

We did everything by our self, we just sent a dxf drawing out to make the holes in a special plastic board and we prepared the rest (e.g we bought the needles and designed the test circuit).
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