Old timer at the shop told me to stop using coolant on aluminum and now I get way better finishes

I always ran coolant on everything even aluminum cause I figured it was safer. Then this guy Mike with 30 years experience walks by my machine and says I'm making chips stick to the tool. He told me to run it dry with a mist of air instead and I thought he was crazy. Tried it on a 6061 part yesterday with a 2 inch face mill and the surface came out mirror smooth compared to before. Any other tips for dry machining specific materials?

3 comments

3 Comments

lilykelly5d ago

Typed that into my phone and immediately walked into a chip conveyor. Totally worth it.

parkera227d ago

6061 in particular has that sticky built in layer of oxide that coolant just kind of traps against the cutter instead of flushing away. Mike probably noticed your chipload was light too, because running wet on aluminum lets you sneak feeds way too high without the finish showing it until the tool wears out faster. Try bumping your rpm up another 500 and cutting your radial engagement in half to really use that air blast for chip evacuation.

martin.felix7d ago

Respectfully, I don't think the oxide layer makes that much difference in practice.