PCBA baking prior to rework

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In regards to baking an assembly prior to hot air (BGA) rewo... - Oct 14, 2002 by kennyg

In regards to baking an assembly prior to hot air (BGA) rewo... - Oct 15, 2002 by davef

kennyg

#21943

PCBA baking prior to rework | 14 October, 2002

In regards to baking an assembly prior to hot air (BGA) rework.... 1) Do people always bake, sometimes or never? Does this depend on whether MS sensitive components are near the rework site? If a BGA is to be removed and reballed, baking is a no-brainer. 2) What time/temp bake cycle do people use? Does this vary depending on themally sensitive components that may be intalled on the assembly? 3) If there are MS sensitive parts near the rework location...how hot can such a part get before popcorning can occur (which would require PCBA baking?) IPC JEDEC J-STD-033 says 200C, this seems high to me.

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davef

#21949

PCBA baking prior to rework | 15 October, 2002

In regards to baking an assembly prior to hot air (BGA) rework.... >1) Do people always bake, sometimes or never? Does this depend on whether MS sensitive components are near the rework site? If a BGA is to be removed and reballed, baking is a no-brainer.

Sometimes, based on the proximity of the MS components.

>2) What time/temp bake cycle do people use? Does this vary depending on themally sensitive components that may be intalled on the assembly?

Varies with the 'mass' of the board. Search the fine SMTnet Archives for demoisturizing bare boards as a baseline for establishing your times.

>3) If there are MS sensitive parts near the rework location...how hot can such a part get before popcorning can occur (which would require PCBA baking?) IPC JEDEC J-STD-033 says 200C, this seems high to me.

200�C seems high to me. Water boils at 100�C.

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