Yes, you can machine aluminum dry. I machine aluminum molds and do all my rough and semi-finish passes dry. When I do dry machining I run an air line from a solenoid to the coolant tube of my machining centers (Fadal) and plug the solenoid cord in place of the coolant pump. All I use is shop air pressure to blow the chips off.
Large/deep pockets and cavities are prime candidates for dry machining. Coolant quickly turns them into swimming pools and the chips can no longer evacuate from them, leaving you with aluminum chip soup. Now your tool starts to recut the chips.
Dry machining is cleaner and brings the cost of using coolant down but there are times when you should still use coolant, drilling and tapping for example. I still do my finish passes with coolant.
My speeds vary between 7000-10,000 rpm and feed rates from 100 - 350 ipm depending on the tool, but dry machining works just as well on slower/manual machines as you found yourself. I spent the first 12 years of my career cutting aluminum and steel on a Tree tool & die mill that had no coolant provision, except for the manual spray bottle and brush method.  |