| Currently, we are baking any PCB before process on SMT, the 'reason' is to dry any possible humidity that could be inner the PCB, it does not matter if the PCB is multilayer or not. We bake PCB's at 107C for 4 hrs and the board must be process into next 8 hours, if not, the PCB needs to be reconditioned again. Evenmore, nobody can tell me if this conditioning is a requirement or not, we just baked as a 'good practice'. Could someone tell me if there is any requirement to bake PCB before processing? Where is that documment? What may be affected if PCB's are not longer baked? Any comment will be welcome ! | | | Carlos: Baking boards is a lousey practice. It increases the oxidation on the solderable surfaces and that makes it more difficult for you flux to do a good job.
There is no requirement that you bake boards.
I worked in shops that baked boards, because they bought boards:
* By the boat-load and stored them in a humid environment for months. Boards are hydroscopic and will absorb moisture. The moisture will tend to boil-off during soldering operations. * With less than 1 mil barrel plating thickness. Thin plating allows moisture in the board to escape through the trough holes and cause very messy and ugly solder connections. This is a result of poor fabrication processes. Our old freind Bob Willis has a procedure for evaluating plating thickness on his site, which is listed in the archives some where.
I say:
* Find better suppliers * Get control of your board inventory * Store boards properly ( see previous threads in the archive) * Stop baking your boards.
My 2�
Dave F
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