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Cool down too fast after bake | cracking and popping heard during cooldown.
726 1 Sep 16.2019, 16:57:25

Hey All,
TLDR; With a panel with low thermal mass, how long should I let it cool before taking it out of the oven? 
I've been impatient and usually after 4 min, when PCB is about 120c, I grab them to cool on a silicone pad while I bake the next panel. Would switching to a Pb solder help since the temps would be much lower? As it sits on the pad, I hear cracking and popping as the solder cools. 
Is this bad?
Controleo 3 B&D toaster oven
Chipquick SAC305 with peak at 225c
I'll keep searching the forum, but I though I'd burn this candle at both ends.
Thanks for any help.

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A****min

Sep 18.2019, 17:36:21

Temperature profile includes both ramp up (warm up), soak, reflow, and cooling periods and both the duration and °C/sec of each period should be controlled.
Putting a hot board on a cool surface is not a controlled process. Additionally, the temperature below which it is safe to handle a board is more like 100°C, not 120.

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