TIL I was running spindle speed way too low for my smaller endmills

I was getting crap surface finish for like a year on .125 endmills and just blamed the tooling. Finally had a senior guy watch me run a part in Phoenix and he pointed out my chip load was all messed up because I was babying the RPMs. Has anyone else had that moment where you realized you were just guessing on speeds and feeds the whole time?

3 comments

3 Comments

ray18923d ago

Yeah that chip thinning thing got me too. I was running a 1/8th inch carbide endmill in 6061 at like 8000 rpm and 15 ipm for months thinking I was being careful. Turns out I needed to push it to 12000 rpm and bump the feed to 40 ipm with some chip thinning calculations. The finish went from garbage to glassy smooth in one cut. Its wild how much of machining is just trusting the math instead of your gut feeling.

ben20624d ago

Watched a coworker cut a part way faster than me on a similar setup and felt like an idiot when he showed me the right SFM. Spent months blaming my machine and getting frustrated over nothing. Chip load is one of those things that seems simple but totally changes everything once you get it dialed.

gray624d ago

Yeah that's chip thinning you saw in action, not just chip load. Different beast but same principle of actually measuring the cut instead of guessing.