harper_smith•19h agoOG Member

Showerthought: Should we use coolant or run dry on aluminum?

I've been running a Haas VF-2 for about 5 years now, mostly doing prototype work out of a small shop in Phoenix. Last month I had this job in 6061 aluminum, a bracket with some tight tolerances. My old mentor always said to run aluminum dry with a mist of air, keeps the chips from welding and you get a better finish. But the other guys in the shop swear by flood coolant says it extends tool life. I tried it both ways on the same part, doing a few passes each. With coolant the surface looked okay but the tool chipped after 30 parts. Dry with air I got a mirror finish and the endmill lasted for 150 parts before I swapped it. So what do you all think is coolant just a waste on aluminum or am I missing something here?

2 comments

2 Comments

schmidt.willow19h ago

Wait, so your old mentor told you to run dry and now you're surprised the dry parts came out better? I mean, maybe it's just me but that sounds like you already had your answer the whole time. The coolant crowd might be fine for stainless but on 6061 it's basically just making a mess and wasting endmills. Plus in Phoenix, a little air mist probably feels nice compared to standing in a puddle of warm coolant all day. Sounds like your mentor knew what was up, idk why you doubted him.

stellas5618h ago

Honestly, you're so right about the coolant mess. I had this exact thing happen to me when I started out, I was convinced you had to flood everything with coolant or the tool would explode or something. Tbh my mentor told me the same thing about running dry on 6061 and I fought him on it for months, thought he was stuck in the old days. Then I finally tried it on a batch of parts and the finish was way better and my inserts lasted like twice as long. Ngl I felt pretty dumb after that. And the warm coolant puddle thing is real, especially in summer it just makes the whole shop smell like a swamp. Plus you don't have to deal with that nasty residue all over your parts if you're doing a quick turnaround.