Baking, whatever objects be baked, boards, BGAs, TSOPs etc, the whole topic is interesting. A level 4 FPBGA that has been exposed to 'normal' floor for 3 days needs about 1 day baking at +125 Celcius or 40 days at +40 Celcius and less than 5% RH. Depending on thickness, some components may need eeven longer drying time. A thumb rule says about humidity: easy in, slower out. So, baking is a clumsy and time consuming step. We avoid baking, instead we specify humidity protected packages when buying, or do we put components in nitrogen boxes. Now, I wonder if someone else lifts eyebrows reading the attached link to an article about drying boxes, namely the inconvinience of plexi N2 boxes. I've never thought of humidity that diffuses straight through the walls and makes sabotage to the nitrogen. Neither have we thought much of the way N2 flows. So, from now on, we will check the boxes with a RH meter. As Ioan said, a little talking about baking may be fruitbringing.
/Inge
PS. Do you use yeast or baking powder?
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Ioan Tempea
Sent: måndag 4 maj 2009 15:25
To: [log in to unmask]
Subject: [TN] PCB baking
Dear Technos,
I know this has been oftenly discussed here, but I would like to lively up the traffic a little bit...
Is there any IPC standard reglementing the bake out time for PCBs, in terms of temperature/dwell time?
Thanks,
Ioan Tempea, ing.
Ingénieur Principal Fabrication / Sr. Manufacturing Engineer
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