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Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Print solder paste on test pad on OSP board

Bryan Sherh

#30472

Print solder paste on test pad on OSP board | 10 September, 2004

Dears, I've a board with OSP surface finish,and I planned to print solder paste on the test pad for easy ICT, because the probe can't reach the OSP covered pad.But to my surprise,after reflow there's much flux residue on top of test pad(or solder) and it's still very hard to ICT because the probe can't penetrate the hard residue layer. I want to know how you deal with the same issue in your factory?Some people said increase the stress of probe,someone said use a probable solder paste...what's your opinion? Thanks a lot for any input.

Bryan Sherh

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#30482

Print solder paste on test pad on OSP board | 12 September, 2004

Well, another alternative is to use a water washable flux.

If you insist on staying with a NC flux, use one that is probable. We prefer to probe solder, rather than copper.

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RDR

#30488

Print solder paste on test pad on OSP board | 13 September, 2004

Use Water soluble if you can, if not I would try the Indium SMQ NC paste, this residue stays soft. I would also change ICT probes to the "drill type".

Russ

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Rob

#30498

Print solder paste on test pad on OSP board | 14 September, 2004

Hi,

There are "Fluxbuster" or "Rotator" pins on the market - we had to use them a few years ago on a flexy board (with OSP).

There is some info from one source at the following link: http://www.isiconnectors.com/mfrs/idi/idipr.htm#Rotator

We got ours from someone in the UK & they worked fine.

Cheers,

Rob.

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#30720

Print solder paste on test pad on OSP board | 27 September, 2004

use water soluble solder paste is the cure for your problem. but if you insist of using NC change your pogo pins to pointed pins.

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