Electronics Forum | Mon Jul 19 21:33:26 EDT 2004 | davef
Are you talking about small 'volcanos' that burst through PTH solder connections? If so, you have moisture outgassing through the PTH barrels: * Plating on the hole of your bare board is too thin. It should be greater than 1 thou [25um]. * Your bak
Electronics Forum | Tue Nov 28 22:34:55 EST 2006 | davef
Almost all boards are hydroscopic. In this, the epoxy holding the board together absorbs moisture. Almost all components are hydroscopic. In this, the epoxy encapsulating the component together absorbs moisture. So, as you heat the board / compon
Electronics Forum | Wed Apr 04 17:40:39 EDT 2007 | davef
Rob: How do you rework blow-holes and pin-holes? PTH plating thickness SB 1 thou or greater. Epoxy is hydroscopic. So, you should control the environment and/or bake the moisture from the boards before soldering. Search the fine SMTnet Archives f
Electronics Forum | Wed Nov 20 16:53:18 EST 2002 | davef
Q1: How important is the bare PCB baking ? A1: Baking boards is a non-value added activity. Q2: What is the temperature for baking @ what RH ? A2: Search the fine SMTnet Arcives for bake recipes. Q3: What would be the impact for the ENTEK finishe
Electronics Forum | Thu Apr 05 08:04:40 EDT 2007 | davef
On finding baking recipes in the fine SMTnet Archive, your problem is not in the flex portion. It's in the rigid [FR4] portion. On baking advice from experts look here: http://www.circuitnet.com/experts/EQ10120.shtml Finally, on reworking your ou
Electronics Forum | Mon Aug 30 14:32:52 EDT 2010 | davef
Steve: Yes, you shall bake prior to thermal cycling. You should be able to download J-033 from JEDEC [ http://www.jedec.org/standards-documents ]. You want "Paragraph 4 Drying." While it's aimed a component parts and not assemblies, J-033 is as goo
Electronics Forum | Sun Jan 19 10:45:04 EST 2003 | davef
For laminated FR4 PCB, we bake between 6 and 24 hours at 100�C. [Search for other bake recipes in the fine SMTnet Archives.] Alot of the determination of baking time is a function of: * Amount of moisture absorbed. * Amount of moisture you need to r
Electronics Forum | Fri Feb 28 08:57:34 EST 2003 | davef
We used to bake [100*C for 6 hours] all of our boards, but no longer bake at all. Before going off, your bake recipe is probaly OK. If anything, it's probably too short. Consider measuring the weight of wet boards, baking for a time, measure, bake
Electronics Forum | Wed Aug 07 08:46:38 EDT 2002 | davef
The time and temperature required for baking moisture from your boards varies according to the conflicting desires to: * Remove enough entrapped moisture. * Desire to retain solderability of solderable surfaces. Search the fine SMTnet archives for s
Electronics Forum | Wed Aug 07 09:05:11 EDT 2002 | davef
N2 PPM vs %RH? With a firm grasp of the obvious, reflow oven manufacturers rig N2 ovens differently than non-N2 ovens. The N2 displaces O2. Usually N2 oven monitor something or other to give an indication of N2 ppm. %RH really isn't part of the eq
