mairomaster , 11-06-2017, 01:45 AM
I don't think there is a standard. It is quite important thing to decide in the beginning, when you are starting developing you libraries, since it might be a pain to change in the future. Here is what layers we use at our company:
M3: Courtyard
M4: Component Body
M5: Designator
M9: Component Origin Symbol (showing the reference point of the footprint)
The layer pairs in the layout are:
M3:M13
M4:M14
M5:M15
Also in the layout we use M1 for a board outline or board panel drawing (depending on if we provide the panel specifications or not) and M17 for a simple board outline.
For manufacturing notes, dimensions, layer stack table and drill table we use the Drill Drawing layer.