Imbeded nails test system
Imbeded nails test system
(OP)
Hi,
I'm doing PCb board test system which incorporate 200-300 test points using pogo pin to test it. I'm having problem with the hardware. In this case, the G-10 ( fiberglass)plate where we press in the pogo pins. I need the locational tolerance less than .002" in order to work properly. Is there anyone out there that can do hole positioning tolerencan +/- .002 or less on G-10 Plate with pin holes is .039". The test pad is .020" SQ.
Anyone out would like to share their experience on this?
Thanks
Kinsrow
I'm doing PCb board test system which incorporate 200-300 test points using pogo pin to test it. I'm having problem with the hardware. In this case, the G-10 ( fiberglass)plate where we press in the pogo pins. I need the locational tolerance less than .002" in order to work properly. Is there anyone out there that can do hole positioning tolerencan +/- .002 or less on G-10 Plate with pin holes is .039". The test pad is .020" SQ.
Anyone out would like to share their experience on this?
Thanks
Kinsrow





RE: Imbeded nails test system
I think either the circuit or the PCB should be redesigned...
----------------------------
Please read FAQ240-1032
My WEB: <http://geocities.com/nbucska/>
RE: Imbeded nails test system
You need a thicker, less anisotropic material.
Mike Halloran
Pembroke Pines, FL, USA
RE: Imbeded nails test system
Is it analog,digital or mixed? Are you so space limited,
that you can't add larger contact pads ( e.g. 1/2 mm square )?
I think you have an impossible job and a significant
redesign is indicated.
----------------------------
Please read FAQ240-1032
My WEB: <http://geocities.com/nbucska/>
RE: Imbeded nails test system
What is anisotropic material?
Thanks
Kinsrow
RE: Imbeded nails test system
Mike agrees that the job as you defined is impossible.
That is all. Now let's see if we can find any solution.
I am afraid it will not be painless or cheap but
-- if you are lucky -- possible.
Please answer:
Analog/digital? what is the size of the board, how many
layers?
Approx. how many percent of the surface is covered by parts ? Are parts on both sides ?
What is the maximal frequency?
----------------------------
Please read FAQ240-1032
My WEB: <http://geocities.com/nbucska/>
RE: Imbeded nails test system
Dimensionally stable and not so directionally different. Remember that typical circuit board has different traits in different directions.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Imbeded nails test system
How do you guys do it out there? There's got to be away to do this better. There are gizzilions electronic products out there?. They do boundary scan already, but I still got hundreds of test points to test.
Redesigning board is out of the questions, when they do they add more component and test points.
Thanks
Kinsrow
RE: Imbeded nails test system
If you don't want the designers to change the boards perhaps you can work this out with the your PCB supplier. Ask them to enlarge the test pads up to 0.050. With their CAM tools this is an easy task and it will automatically flag any line spacing violation, which they can probably correct too.
RE: Imbeded nails test system
It sounds like the designers have no qualms about lobbing test points everywhere...
I'd suggest you start figuring out how much it actually costs per test point and start working on management to point out that these over generous test arrays are coming right out of the bottom line somewhere.
At some point, far below your point, it starts making sense to put testing into the board since that would be cheaper than probing 200 points on every board. That also allows the product to report problems in the field!
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Imbeded nails test system
Thanks again,
Kinsrow.
RE: Imbeded nails test system
I think these are your choices:
1.) Reduce the TPs number by better selftest
2.) add more layers to create space for larger pads.
----------------------------
Please read FAQ240-1032
My WEB: <http://geocities.com/nbucska/>
RE: Imbeded nails test system
With the increased density of circuits, bed of nails tend to disappear (it just becomes not feasible to have so many pads for test) to be replaced with jtag and flying probes. Again the product has to be designed for it, and the complexity and cost of such test equipment and the development goes a step up.
Going with such techniques also involves large volumes, and a consequential increase in the yield of good products. Then like you say just the easy repairs are done and the rest is thrown away. Also many of the chips used in cell phones are custom made, with testability in them. Don't ask where do the defective units go when they're sent for repair.
Then you are stuck with designers that aren't interested in helping production to improve. It is your problem, right? You complainer! Welcome to the harsh world of low volume high-tech.
RE: Imbeded nails test system
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com