I am going back and forth on this issue (again):
Should the fab drawing reference IPC slash sheets for material call-out;
or should the material reference just be generic requirements?
I.E.: "NEMA GRADE FR4 IAW IPC-4101-nn; UL 94V0".
"NEMA GRADE FR4, UL 94V0, Tg 130C MIN; Td 320C, T288 >/= 4 MINUTES, Z AXIS EXPANSION 3.5% MAX".
I have conflicting opinoins on using IPC slash numbers versus calling out the requirements in a more generic fashion.
Any input would be appreciated. I am trying to use the least amount of information
that yields the maximum production efficiency with the lowest prices. Haha...isn't everyone?
I would agree to keep it as generic as possible but if your min requirements for design
are the 130Tg etc I would specify it that way. Ref the overall IPC material spec
is fine but it there are key min requirements like the Tgm & Td I would
tend towards wanting to define that in words on the dwg.