Old timer at my shop said I was crashing my end mills too hard

When I started running the Haas VF-2 at my shop in Cleveland, this guy Bob with 30 years experience kept telling me to back off my feed rates on 4140. I was pushing .005 per tooth at 150 IPM and wondering why my inserts were chipping after 10 parts. He finally made me drop to .003 at 110 IPM and the finish looked way better and I got 40 parts out of one tool. Has anyone else had to unlearn aggressive speeds to get better tool life?

2 comments

2 Comments

dylan_thompson7d ago

Stopped me dead in my tracks when I read you were running .005 per tooth at 150 IPM in 4140. That's basically trying to shove a butter knife through a brick wall. My first couple years on the job I was just hammering the green button and hoping for the best, treating every cut like a race. Bob sounds like the kind of old timer who's seen a hundred guys come through thinking they can outrun physics. Those numbers you dropped from are exactly the kind of stuff I'd put in for aluminum and then wonder why my steel parts looked like garbage after ten cycles.

emmam677d ago

Ha! Yeah, that's pretty much the definition of trying to win a race you already lost. I've definitely been there myself, thinking more speed equals more parts, then wondering why my inserts looked like they got into a fight with a blender. Bob probably saved you a ton of money in broken tools and scrapped parts. It's funny how the guys who've been doing it for decades always seem to know exactly where the sweet spot is, not the fastest spot.