Dear Jerry,

We regularly assemble multilayer flex or flex-rigid boards and handle them as MSL6 parts with 6h shelf life prior to reflow. As far as I understand it, according to J-STD-0033 baking is mandatory for MSL6 devices no matter how they are packed, so we do.
We also ask our subcontractors to do so when outsourcing this kind of assembly.

I agree it might look highly conservative, though, but our internal PCB manufacturing workshop expert confirmed we'd better do so.

So far we never faced any issues this way on few thousands we had the chance to handle.

Best regards
Sylvain Kaufmann


-----Original Message-----
From: TechNet <[log in to unmask]> On Behalf Of Jerry Dengler
Sent: 10 January 2020 13:53
To: [log in to unmask]
Subject: [TN] Flexible PCB's

TechNetters,

 

We reviewed documentation from a flexible PCB manufacturer and saw that they recommend baking of the flex boards prior to assembly even if they are brand new boards in a Moisture Barrier Bag.

 

Why wouldn't these be handled like any other moisture sensitive component?

 

How many of you that work with flexible PCBs are baking them even if they come out of a MBB with A HIC card that shows no real moisture?

 

Thank You,

 

Jerry Dengler

Production Manager

Pergamon Corporation

380 Crooked Lane, Unit# 3

King of Prussia, PA  19406-2567

U.S.A.

(610) 239-0721 Phone