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Boards delaminated after wash

Yngwie

#17191

Boards delaminated after wash | 14 August, 2001

I experienced assembled boards delaminated after washed.

You know...those old datecode PCBs that I was talking about a few weeks back ? I was forced to use it, and of course prior using it I've baked them. I've baked them at 125 Deg for 4 hours and/or 100 deg C at 8 hours ( Is the specs. rite ? ). The boards came from 2 diff. vendors. One of them is OK and the other one delaminated after wash. They were OK at post reflow. Both boards are of the same age. What could be the rootcause of the problem ?

Thanx in advance.

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#17193

Boards delaminated after wash | 14 August, 2001

BOARD BAKING SCHEDULE: Bake time depends on the board thickness and construction. For laminated FR4 PCB, we bake between 6 and 24 hours at 100�C.

ROOT CAUSE OF THE PROBLEM: Heating moisture entrapped between the laminations of the board too quickly.

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Hussman

#17194

Boards delaminated after wash | 14 August, 2001

I thought Dan saw the delamination after wash - not baking? What temp are your dryers on the washer set at?

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#17195

Boards delaminated after wash | 14 August, 2001

Dano's confused. The boards are delaminating during soldering. The delamination just isn't immediately appartent after soldering.

Stepping backwards. It's remotely possible that if the boards were blistering hot from soldering and then dumped in to the washer, that could cause delamination. But then again, like your drier suggestion, if that was the cause why wouldn't boards from both suppliers be affected?

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