Electronics Forum | Thu Jan 28 08:58:10 EST 1999 | Peet
| | i am working with the noclean process and getting white residues on the bottomside of the board probably due to the | | wave soldering flux.i am using a no-clean solder paste and a noclean wave solder flux.The boards passed the accelerated tempe
Electronics Forum | Sat Jan 23 07:08:54 EST 1999 | Graham Naisbitt
| I have boards coated with Humiseal 1B73. At a late point mfg. site we need to remove a series of 0603 resistors for optioning purposes. I have been trying to determine the fastest, easiest way to re-coat the pads after removal. Drying time of the c
Electronics Forum | Tue Oct 13 18:28:51 EDT 1998 | Graham Naisbitt
Upinder, Using IPA does not cause the residue, it simply exposes it. Given that all fluxes leave reisdues, it follows that these MUST be benign - but how do you know, and how do you control it. You are using flux to remove oxides and give you a go
Electronics Forum | Wed Jan 27 09:00:56 EST 1999 | Chris Fontaine
| | I have boards coated with Humiseal 1B73. At a late point mfg. site we need to remove a series of 0603 resistors for optioning purposes. I have been trying to determine the fastest, easiest way to re-coat the pads after removal. Drying time of the
Electronics Forum | Tue May 11 07:50:52 EDT 1999 | Graham Naisbitt
| If I clean my assembly and find no visable contamination with the unaided eye, do I need to do cleanliness testing prior to conformal coating? | Douglas, It is highly advisable to test for ionic contaminants because a coating seals in as well as
Electronics Forum | Mon Jun 08 20:03:07 EDT 1998 | Dave F
| Chiakl | Ion Chromatography has been perfectly described by Dave, but here are a couple of extra considerations: | Ion Chromatography will tell you precisely what is present on the surface of your board/assembly but it will not tell you whether it
Electronics Forum | Sat May 16 19:31:27 EDT 1998 | Graham Naisbitt
Gentlemen, Please consider that ionic testing is designed only for detecting ionic contaminants. Yes there are instances of non-ionic contaminants that cause premature circuit failure. However, more importantly the prevailing specs are less than adeq
Electronics Forum | Thu Jan 15 17:07:18 EST 1998 | Graham Naisbitt
A reasonable assumption but it could be a reaction between your solder resist and the fluxes in the wave and reflow processes. The issue is, how will anyone really know? Then, are they likely to compromise circuit reliability? I have a method that wi
Electronics Forum | Mon Dec 22 18:20:33 EST 1997 | Graham Naisbitt
Brett and Chis, The method I understand to be the most popular is the use of micro-blasting or abrasion. In other words mechanical rather than chemical removal. However, that is only part of the problem - how do you repair the coating? The technique
Electronics Forum | Wed Apr 08 18:15:18 EDT 1998 | Graham Naisbitt
Scott, I am not really in a position to answer this as fully as I would like because most military work with which I am familiar is subject to some degree of secrecy most especially on the internet. At least we have signed up to such restrictions. Ho
