reccomendation for turning hardened stainless

[poster]

Does anyone know of a good tool for cutting hardened stainless with a Rc of 52? I have some dies that have a 24"ID that need about 1/8" taken off. Since its a die there are also a thousand through holes radially in the part. The interrupted cut is extremely hard on inserts and we haven't found a solution for a quick turn-around on these yet. We have tried TNMG inserts from Kennametal in there recommended grades, as well as Green Leafs WG-300s. There is not as much of an issue on the outside edge before the holes start (uninterrupted) vs cutting across the holes (interrupted). we may resort to grinding next, but would really like to stay away from that. I also have the option of helically interpolating the bore on a milling machine with an endmill, what do you think?

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[mactec54]

Does anyone know of a good tool for cutting hardened stainless with a Rc of 52? I have some dies that have a 24"ID that need about 1/8" taken off. Since its a die there are also a thousand through holes radially in the part. The interrupted cut is extremely hard on inserts and we haven't found a solution for a quick turn-around on these yet. We have tried TNMG inserts from Kennametal in there recommended grades, as well as Green Leafs WG-300s. There is not as much of an issue on the outside edge before the holes start (uninterrupted) vs cutting across the holes (interrupted). we may resort to grinding next, but would really like to stay away from that. I also have the option of helically interpolating the bore on a milling machine with an endmill, what do you think?

Yes do it on your mill if it will fit

[poster]

yes, it will just fit. I will find a suitable end mill and give it a shot. heres hoping.

[poster]

The endmill dulled very quickly and i was only able to remove material 1" along the width. The part is 7" wide. That is another issue i would need 3.5" depth of cut, i could cut in increments of course, but would need 3.5 of endmill min sticking out of tool holder, and also flip the part once

[G59]

What type and size of endmill did you use? Feed Speed DOC WOC etc.......
3.5" is no problem for larger (>1") endmills.
Maybe an endmill that using carbide inserts with reduced shank would be better..

[poster]

What type and size of endmill did you use? Feed Speed DOC WOC etc.......
3.5" is no problem for larger (>1") endmills.
Maybe an endmill that using carbide inserts with reduced shank would be better..

A kennametal harvi grade 633 5/8 dia. DOC was 1" WOC i tried .090and .040, 125sfm and .002"/tooth feed. I did try speeds/feeds up and down while it was running up and down 100% . Lots of squealing and overall time to complete the cut was far too long

[rcs60]

have you tried polycrystaline cubic boron nitride these should hold up better than the whisker reinforced ceramic of the greenleaf i would also go with an 80 degree insert as the tool tip will be stronger than the triangle insert
the PCBN have grades for finishing and roughing
tool tip radius can also play a part in longevity of cutting time

[poster]

have you tried polycrystaline cubic boron nitride these should hold up better than the whisker reinforced ceramic of the greenleaf i would also go with an 80 degree insert as the tool tip will be stronger than the triangle insert
the PCBN have grades for finishing and roughing
tool tip radius can also play a part in longevity of cutting time

No i have never tried these, i will look into it, thanks

[G59]

My biggest concern is the total depth of cut @ 3.5" it would be much easier to use the largest cutter possible especially when cutting hardened anything. Stainless in particular doesn't like any speed. At 3.5" stickout, a 5/8" endmill will flex and chatter(squeal) .

[mactec54]

No i have never tried these, i will look into it, thanks

Don't waste your time, having interrupted cut over holes will kill these tip tools and ceramic, either would work very well if you did not have the interrupted cut, seems like rough turn then finish grind, that's a lot of material to remove from heat treated SS

[G59]

He's given up on turning it so most likely going to mill it.

[poster]

just waiting on some "different" endmills more suited for harder materials to show, so I can try them out. I really hope I don't have to grind these. Also there is an small area without the interruptions, this area is much more easily machinable, so its the interruptions causing most of the headaches. What about a multi-insert helical shell mill? or would interruptions come into play with these as well? I've never tried one

[G59]

Multi insert shell mills would work depending on if you have the room to work with them. Interruption cuts in hardened workpieces are always problematic for any cutter. Take it slow and everything will pan out.

[mcphill]

How many holes? Can you fill them? Aluminum or even steel inserts pressed in to the holes? Maybe even an epoxy fill would give enough resistance to the cutter to allow the cut to progress. If it is a die, the epoxy could be burned out prior to first use...

[mactec54]

How many holes? Can you fill them? Aluminum or even steel inserts pressed in to the holes? Maybe even an epoxy fill would give enough resistance to the cutter to allow the cut to progress. If it is a die, the epoxy could be burned out prior to first use...

If you were to fill the holes in this case, it would have to be the same material and same hardiness, or it would fail just the same

[KilrB]

We're talking about a die here ...

An acceptable finish will never be achieved turning or milling through an interrupted cut.

Rough turn or mill and grind, as already suggested, is the solution here.