Im having some difficulty milling 0.9mm sheet Aluminium (5251). I know the grad isnt the best for machining but its the most readily available.

I have no issues machining 4mm plate using 3mm 2flute bit at 12000rpm 200mm/min.

The thin sheet doesnt cut cleanly and Ive tried different feeds/speeds. What I really want to achieve is this:-



Any help greatly received.

Ian