"nails" for bed of nails test jig

[mike diack]

I need to make a test jig for production testing (and in circuit
programming) a widget I have designed. I'm looking for a source of
springy pointy "nails" to pick up on the test pads I have put on the
PCB. I'm aware of the ones available through RS and Farnell, but those
things are **HUGE**, I need something of similar design / function but
half the diameter (preferabl;y a lot shorter as well). Any ideas,
folks ?
cheers
Mike

 

[Dan Major]

[email protected] (mike diack) wrote in @News.xtra.co.nz:

I need to make a test jig for production testing (and in circuit
programming) a widget I have designed. I'm looking for a source of
springy pointy "nails" to pick up on the test pads I have put on the
PCB. I'm aware of the ones available through RS and Farnell, but those
things are **HUGE**, I need something of similar design / function but
half the diameter (preferabl;y a lot shorter as well). Any ideas,
folks ?

They're called "pogo pins". Try:

http://www.emulation.com/catalog/pogo/
http://www.goldtec.com/Product-Pogo_Pins.htm
http://www.mill-max.com/pin_rec_catalog/search_results.cfm?
part_description=Spring%2DLoaded%20Pin&pin_or_rec=pin&CFID=2007539
&CFTOKEN=58130787

or additional google search on pogo pins or spring pins

 

[Bill Sloman]

I need to make a test jig for production testing (and in circuit
programming) a widget I have designed. I'm looking for a source of
springy pointy "nails" to pick up on the test pads I have put on the
PCB. I'm aware of the ones available through RS and Farnell, but those
things are **HUGE**, I need something of similar design / function but
half the diameter (preferabl;y a lot shorter as well). Any ideas,
folks ?

The depressing thing about shorter, smaller "nails" (pogo pins,
spring-loaded contacts) is that you need bigger test pads on the PCB.

The point of the sprung contact can't be relied on to sit at the geometrical
centre of the mounting hole, and the smaller the mounting hole, the bigger
the proportional error. Nor can the axis of the sprung contact be relied to
be exactly normal to the plane of your board, and the shorter the assembly,
the larger the tolerance.

This means that if you use smaller spring-loaded contact assemblies, you
have to mae the test pads on your PCB bigger to mae sure that the point of
the sprung contact lands on copper rather than solder resist.

You've got to layout your test points to suit the sring-loaded contacts you
want to use, rather than trying to buy spring-loaded contacts to fit test
points placed to accomodate the layout you've been given.

Retrofits are always much more difficult than designing from scratch.

 

[[email protected]]

I need to make a test jig for production testing (and in circuit
programming) a widget I have designed. I'm looking for a source of
springy pointy "nails" to pick up on the test pads I have put on the
PCB. I'm aware of the ones available through RS and Farnell, but those
things are **HUGE**, I need something of similar design / function but
half the diameter (preferabl;y a lot shorter as well). Any ideas,
folks ?
cheers
Mike

www.pccp.com.tw
http://www.qatech.com/products/index.htm

 

[nospam]

The depressing thing about shorter, smaller "nails" (pogo pins,
spring-loaded contacts) is that you need bigger test pads on the PCB.

The 'nails' are long because testers have a regular matrix of sockets on
the bottom that they plug in to. The pins are then deflected to line up
with the pcb holes/pads by custom drilled perspex sheets.

That is what is done for bare board testing anyway, the custom test jig is
then just a couple of sheets of drilled perspex and reusable pins.

 

[qrk]

[email protected] (mike diack) wrote in @News.xtra.co.nz:


They're called "pogo pins". Try:

http://www.emulation.com/catalog/pogo/
http://www.goldtec.com/Product-Pogo_Pins.htm
http://www.mill-max.com/pin_rec_catalog/search_results.cfm?
part_description=Spring%2DLoaded%20Pin&pin_or_rec=pin&CFID=2007539
&CFTOKEN=58130787

More to add on to Dan's list...
http://www.idinet.com/ (down to 0.25mm centers, easy to get thru
Newark (Farnell is connected w/ Newark)).

http://www.ectinfo.com/files/product/frame_pogo.html (maker of Pogo
(tm) contacts, down to 0.4 mm centers)

Mark