Electronics Forum | Wed Jul 27 09:58:05 EDT 2011 | davef
Pressure printing systems Conventional stencil printing techniques have fundamental limitations as regards paste handling: The volume of paste available for printing is limited, so frequent replenishment is necessary Paste is difficult to c
Electronics Forum | Fri Aug 22 00:25:20 EDT 2003 | mantis
Kenny, Out of curisoty why do you need to paste the vias.Is it due to contact reliability at test.Can these vias not be soldered during wave process (if any).Can the Style of probe used in the ICT test fixture not be changed to accomodate these unsol
Electronics Forum | Fri Aug 22 09:41:49 EDT 2003 | davef
Mantis: Kenny reflows paste on [wave solders] all via, not just the test via, to plug the via and provide for a pressure seal between the board and the test fixture. Beyond that, since solder is softer than copper [and fills the hole better], solde
Electronics Forum | Tue Aug 26 21:12:24 EDT 2003 | iman
depends if your water wash process is manual or automation? important is the water residue inside the via holes is adequately blown out. As long as the water-flux residue is out, testing down the line should not be a issue, at least from theory and o
Electronics Forum | Thu Aug 21 23:35:20 EDT 2003 | kennyg
For ICT purposes I may need to print solder paste on 0.015" test vias. No-clean is not an option for this assembly and OA seems the only choice. Can flux be safely removed from inside the via from the other side during a standard water wash process
Electronics Forum | Fri Aug 22 09:44:45 EDT 2003 | davef
Kenny: Since you need to use water soluable flux and can't use no-clean, consider asking your board fabricator to plug the via.
Electronics Forum | Mon Sep 27 11:40:50 EDT 2004 | grayman
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.
Electronics Forum | Mon Sep 13 18:34:31 EDT 2004 | russ
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
Electronics Forum | Fri Sep 10 09:39:32 EDT 2004 | Bryan Sherh
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) an
Electronics Forum | Sun Sep 12 08:30:29 EDT 2004 | davef
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.
