Tried a 0.001 inch slower feed rate on a tight tolerance part and it wrecked the finish.

Slowing the feed on a 316 stainless job yesterday gave me chatter marks I couldn't dial out. Spent 3 hours reworking it. Has anyone else had feed rate changes backfire like that?

3 comments

3 Comments

the_elizabeth8d ago

Used to be one of those guys who thought slower feeds always meant better finishes. Tried it on a 304 stainless job last month and the part came out looking like a washboard. Vibrations just built up and wrecked everything. Thought I could sneak in a perfect mirror surface but the cutter just started hammering. Definitely changed my mind on that whole approach.

noah_webb8d ago

Man, I feel your pain on those chatter marks,they're a real killer.

jesse_craig268d ago

@the_elizabeth nailed it with that vibration issue. I read a post on a machining forum last week that talked about how slower feeds can actually let the material work harden in stainless before you get a chance to cut through it. That's what makes the cutter start hammering, like she mentioned. The guy said he switched to a higher feed rate on 304 and the chatter marks disappeared, even got a better surface finish. It goes against everything you first learn but the vibrations just get cancelled out by the constant cutting pressure. You ever tried pushing the feed rate just to see what happens?