I have read the same thing. 105 - 125C around 4 hours. Our PCB supplier has had issues with the pressing time in there process and we are seeing more delamination on our boards again. They have recommended we bake our existing stock, 5 boards stacked in the oven, at 180C for 2 hours (including ramp). My main concern is the solderability of the ENIG finish after this baking profile. They have shown me some pictures after bake and the gold is darkening. They are asking us if this is acceptable because the boards passed a solder dip test. We are going to bake some boards ourselves, paste and reflow to see the impact. Any thoughts on the 180C bake temp? It seem as though they want the bake temperature above the Tg temp (170) not sure why?
Rob Strecker
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier /*
Sent: Monday, May 04, 2009 7:57 AM
To: [log in to unmask]
Subject: Re: [TN] PCB baking
Hi Ioan,
No there is not, and there really cannot be.
The temperatures used are in the range of 105 to 125-I tend towards 105 C, but the duration depends on a whole lot of factors. Among them: moisture content [bake time ranging from 0 to 24 hours plus], construction [thickness, P/G layer location, PCB resin, resin content, PTH/via pitch/diameter], reflow process/temperature, etc.
My recommendation is to determine it yourself on some coupons supplied with the PCBs.
Werner
-----Original Message-----
From: Ioan Tempea <[log in to unmask]>
To: [log in to unmask]
Sent: Mon, 4 May 2009 9:25 am
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
30 ans déjà! - Already 30 years!
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