Hardmilling Stainless

[Rosko]

Hey guys, I have some ESR 420 stainless @52 Rockwell to hardmill and was wondering if anyone could provide me with some starting speeds and feeds and depth of cut etc. The cutter is a Millstar bullnose endmill, 6 flute .1875 diameter with a .03" radius, AlTiN coated. The only info I'm finding with these cutters from the manufacturere are for their ballnose selection which I don't think translates over to a bullnose very well. I'm waiting to hear back from them but I thought that I'd check here as well as I know alot of you are hardmilling on a regular basis. Thanks in advance!

[Matthew Hajicek - Singularity]

I'd start with an SFM of about 200, and chipload of .0001 to .0002 per tooth.

[MAKINOPAT]

OSG recommends around 2000 rpm and 110 ipm with about .0045 to .0055 depth of cut. I finished some thin stainless plates a few weeks ago with a similar cutter and ended up running about 90 ipm and 3500 rpm taking .004 finish cut! hth

[Rosko]

I heard back from Millstar and they said to run it at 300-400 sfm with .0008" - .0012" chip load finishing at .0012" depth cuts.

 

For the .1875" cutter with a .03" corner radius he said to figure RPM for a .125" diameter so I came up with ~6000 RPM and 36 IPM feed. So far so good, its cutting like butter!

 

Thanks for the help guys!

[Hardmill]

Your gonna want to start at 500-600sfm.

3-5 step over and up to 3 times dia depth cuts.

 

Email me if you need anymore specifics.

 

 

PEACE

[mold100]

+1 to hardmill-

 

I run 420 52 rc right around 600 closer to 660 on my roughing sfm, with a .0006 to .001 chipload. I generally use mostly Jabro (seco) tooling exclusively. I run down to a 1mm ball at 600 sfm or close to it. The biggest issue with 420 is it actually isnt hard enough, its more gummy than say 56 rc S-7, or 54 H-13. Comparable to your millstar typical for me is a 4mm bull nose (.0197 cr)that I would run in exact same material is 14000 rpm material @ 54 imp for roughing .015 doc and 60% step over

[FLIPPER™]

quote:

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+1 to hardmill-

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Hey whataya want. It's in his name........