Tool life?

[mmurray70]

I'm trying to mill stainless and getting very short life from my end mills. I'm new to stainless and am just wondering what kind of life should I expect from them? I've tried just about everything but nothing seems to be working out for me.

I started off trying to cut the part with 1/16" end mills. Tried all sorts of different speeds, feeds and depth of cuts. Seems like I can get approximatly 25 minutes and thats it. Tool dulls and then snaps.

So I then bought some 3/32, 2 flute end mills. Tried cutting at 50 sfm, 0.015" DOC and 8 IPM (~0.002" per flute). I got similer results, about 30 min and the tool was obviously duller at the very tips. Kind of rounded out. This was the cycle time of the part, but I would not be able to make two runs from the same tool.

I also tried running the same setup as above, only at half the speed and feed. Took about an hour this time (obviously) and the tool did seem to have wear on it, but notably less. And time is getting to be a problem when going this slow.

As I said, I'm new to stainless. Is this all I can expect for tool life in stainless? Doesnt seem like I can get it any better. Any advice would be great. Thanks!

[mmurray70]

One last thing, What kind of feed should I be using? Everything I know about stainless is to keep it cutting so I kept the feed high. Could this be killing my tools? Have I gone too far?

[SGW]

What variety of stainless? Some of the alloys aren't too difficult to machine...then there are the others.

Coolant might help -- I assume you don't have a coolant setup, or you'd have mentioned it. In the absence of anything else, cutting oil slathered on with a brush will do pretty well.

[mmurray70]

I'm not too certain on the alloy to be honest. I got it from a metal fabrication place instead of my regular supplier (didnt need a full sheet).

I'm using flood coolant too by the way.