Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Blistering of PCB during lead free assembly

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Gary Kemp

#39220

Blistering of PCB during lead free assembly | 19 January, 2006

We are experiencing a blistering problem during our process of lead free assembly. The customer has supplied us with the bare fab rated at 140 Tg. I am under the assumption that the Tg rating should at minimum be 170. Does anyone know if there is a method of assembling this board with a 140 Tg rating AND a 5 zone reflow oven? Any insight is appreciated.

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#39221

Blistering of PCB during lead free assembly | 19 January, 2006

Specifically, what element of the bare board is blistering?

Tg of 140 could be acceptable. Search the fine SMTnet Archives for background on decomposition temperature [td]

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Gary Kemp

#39244

Blistering of PCB during lead free assembly | 20 January, 2006

The mask/copper layer is exhibiting popcorn blistering following reflow. With profiling we know that the assembly does not see anything close to 250 C, rather around 238 C.

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Reflow Oven

Plasma Prior to Conformal Coating