Old machinist told me to run my toolpaths backwards on a tricky part

Had a veteran CNC guy at a shop I used to sub for tell me to reverse my climb/conventional direction on a tricky stainless job. I thought he was crazy since everything I learned said stick to climb milling for finish. Decided to try it on a test piece last month and my tool life jumped from 4 parts to 12 per end mill. The harmonics just shifted enough to stop that chatter I was fighting. Has anyone else gotten advice that went against the textbook but worked out way better?

2 comments

2 Comments

alex_johnson4h ago

That part about running less coolant on 316L is wild to me because I've always been told drown it or the work hardening will eat your tool. Did you have to mess with speeds or feeds to make that work, or did the reduced coolant alone fix the stringy chip problem? Because I tried that on a 304 job once years ago but I think I was running too fast for the tool to handle the heat without the flood. I'm curious if the key was also slowing the RPM way down so the heat had somewhere to go, or if just cutting the coolant flow was enough to change the chip formation on its own.

riley_schmidt5h ago

I had a guy at a shop in Seattle once tell me to run my coolant at like 80% less than normal on a tough 316L job. I thought he was nuts because every setup I'd ever seen had flood coolant blasting away. Tried it on a whim and the chips actually started breaking off clean instead of this stringy mess that kept wrapping around the holder. It was one of those things where I had to fight my own brain to not reach for the valve.