| | We currently bake plastic SMT parts in accordance with the IPC guidelines for moisture sensitive parts. Because we have double-sided boards that are subjected to either an aqueous or semi-aqueous cleaning process, we do a 24 hour bake at 125 deg. C after the first side of the board is reflow solder and cleaned. | | Does anyone know of any studies to indicate either of the following: | | 1. Is baking after the first side of the board is solder and cleaned really necessary if the board is processed within the time frame recommended for moisture sensittive parts? | | 2. Does vacuum baking reduce the cycle time for moisture bakeout? If yes, what vacuum ovens are recommended and what is the bakeout schedule? | | Thanks, | Pete, | Not to pry but whatcha buildin'? If that's proprietary, no big deal. The reason I ask is because when I have built stuff for the medical industry, for example, I have to follow rigid process guidelines. Sometimes, even some consumer electronics customers designate processes. My point is this; You don't need to bake after the first component population / reflow. I never did and I never had a problem. I've built about a bazillion different assemblies too so my statement is not lacking the backing. I think Wayne pretty much nailed the vacuum oven part. I used regular convection / baking ovens when trying to clear moisture from parts. You DO want to wash after your first SMT assembly operation. I assume you're running a water soluble process. Not washing would more than likely turn your flux residue into something just short of concrete if you you pass that stuff through a second reflow profile. | Cheers, | Justin Justin, You are right about cleaning after first pass. I was lost in space again for only the second time in my life, but you brought me back. We have no problem Justin. Thanks, Earl Moon
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