Flex Rigid PCB in PNP Machine.

[mrpackethead]

How are Flex Rigid PCB's run through Stenciling and PNP?    How do you keep them flat?

[mikeselectricstuff]

Custom fixturing or vacuum bed.

The former could be as simple as a sheet of FR4 and some kapton tape

[Mr. Scram]

Good question. I'm wondering the same about full flex.

[mairo]

What Mike is saying. Custom fixtures is what I have seen mostly here in AU for the assembly and later for the test.

[SMTech]

Pure flex PCBs go through the whole process on custom fixtures. Rigid-Flex, with suitable Panel borders should be able to go through fairly normally if you can't justify a fixture, tho' you may need to have more than your std board support to keep it properly supported. There are some good whitepapers/articles out there discussing them, flex is very hygroscopic so how it is stored an treated before reflow is critical or it can delaminate, the adhesive in the flex layer is also quite sensitive (Low TG) which means the fixture might well shield the flex section or you might shield it with some form of cap either fitted by the SMT or popped on between placement and reflow if you have a suitable gap between the two.