Hello!

I have a problem with what specifications is needed for baking multilayer PWBs? Usually our PWBs here are about 0.125” or less and there are also thick ones like 0.25”. These boards are multilayer ones with as many as 30 layers. And has big internal ground planes.

I haven’t found a document(as to my research) regarding the approximate temperature needed for baking PWBs and not damaging components like thru hole and the heat sensitive ones.

I only read something regarding the baking time for components having been exposed beyond its floor life.

Can you help me with this? I really want to make a general rule on how much baking temperature is needed for an FR4 board with the above thickness and with components without resulting to extra damage into the board as well as the components.

I’m definitely not an expert in this, but do you really need to bake the boards? Some components will absorb moisture, so it’s important to bake them before soldering to avoid the pop-corn syndrome, where the moisture inside boils can causes the chips to explode. I believe most of those chips require something like 24 hours at 100 deg. C or so.

Do you have any links talking about baking PWBs?

IPC’s J-STD-020 and J-STD-033 appear to address moisture sensitive chips, and IPC-2221 talks about general standards for PWBs, but I don’t see anything that talks about boards in particular.

I think you would want to find the most heat sensitive component and adhere to its temperature specs.

I’m going to move this to the soldering forum…