Bed of nails?

yes just a gold dot in the right place.

the test pins I've used is two parts, a receptacle and the pin

the receptacle has "lip" so when you put it in a hole of the specified size it goes in to the right height

When I did some bed of nails testing we didn't solder them in the test bed, the receptacle was just press fit in. The bed was made from some kind of br own composite/plastic about 10mm thick, I think we got them drilled at our pcb manufacturer

alignment was with a few pins with tight fit in holes in the PCB

-Lasse

Did you intend to give a link or picture? There are a few companies that make various styles of "pogo pin" test contacts. I think I got mine from Newark. Under test-measurement-inspection / test connectors / spring loaded, they have some from Mill-Max and Interconnect Devices. I think the fixture I built used Interconnect Devices pins and sockets.

Jon

ICT or bed of nails can be mounted in plexiglass or other sturdy/rigid plate of sufficient thickness. A FR4 by it self is not rigid enough if the pins are long.

The placement is done on the PCB and with hole locations copied to the guide plate, which is preferable drilled on a CNC machine

Cheers

Klaus

D'oh.

Pogo pins.

The pointy ones drop nicely into plated holes. The crown types can contact a solder joint or the soldered end of a thru-hole part. The pointy or round-end ones might be good to contact your dots.

We machine a hole array in a piece of delrin or corian, to support the pins. You can use the DUT pcb as a hole drill guide.

You can usually buy slightly-used pogos on ebay, practically by the pound, a few per cent of the normal price. The ones I have work fine.

I made these out of ebay pogos

If you have the space, use VIAS. You get a better contact with the 'hole' even if it's flow soldered board.Either in a strip or a 3x2 array etc.

Having space is the operative constraint. This notion came about because I was pondering how I might wedge some more parts onto an already packed board -- some little gold dots will be easier to accommodate than vias.

I will keep that in mind, however.

Sorry Tim, wrong end of the stick, sort of. My UK supplier is CODA-PIN:- Coda systems Ltd. They're very helpful.POGO pins come in all sorts of lengths, 'pin' style and spring strength. As others, best material for the base is DELRIN.

Samtec has a connector, board to board that just needs a foot print for the mating half. All you need is a fixture to apply the force to keep the connector in place.

Card edge stuff works too, Maybe usb-A style?

Cheers

if you have the luxury of a mating PCB, you could use those 'wires' mounted inside insulators that simply transfer across. Captured on their ends and compressed, the wires don't care about alignment, since each one is insulated, however the mating area has to line up though. You can get better than 20 mil centers [I think] so you can really get some 'smallish' stuff in there.

I think Samtec makes them, these are 1mm spacing PCB-PCB connectors.

OK, these are lower profile than the Interconnect Devices units I used years ago. Those had a socket part that was about 2" long, with a wire-wrap tail. Then, there's the spring-loaded pin that fits into it. So, I used the board's drill file to make up to pieces of PC board material with holes that match the pattern of places I wanted to probe. The lower board had little holes for the WW pins, and these were soldered to fix the sockets in place. The upper board had larger hoes for the body of the socket, and aligns the pins so they don't deflect sideways.

Jon