Better tool life milling 316? HSM??

mmurray70 · May 15, 2020

Wondering what cutting parameters you guys recommend these days when milling 316? I use kennametal/hanita endmills and I find their old school feeds/speeds work fairly well but it is pretty slow. I've tried experimenting a little with HSM with slight improvements, but I feel there still might be room for improvement.

Doing a little research I see a lot of variation in recommended speeds/feeds, stepover, coolant/no coolant, brands, etc. Seems like everybody is all over the place. So what works for you guys? Post up what you find the best. Tool life is more important then a little longer cycle time for me on most parts. Mostly wondering about roughing with 3/8 and 1/2 endmills. Thanks

TeachMePlease · May 16, 2020

Well, what are your current parameters? What machine are you running on? How sturdy is your part/fixture? Slotting/pocketing or profiling?

For roughing anything steel, this is what I grab from the tool crib: Helical Tool

It's the best I've tried, doesn't necessarily make it THE best, but it's what I've got, and I like it.

Most of my steel work is modifying things on the Bridgeport, and no matter what steel I'm cutting, or how hard it is (within reason), this thing goes through like butter, with almost no tool pressure. I imagine it'd really kick butt in a good VMC application.

ChipSplitter · May 16, 2020

You COULD try using an endmill for titanium. The sharper edge combined with an HEM strategy might give you the life you're looking for.

I have so far successfully managed to stay away from all SS except 303. Am I blessed beyond measure?

SND · May 16, 2020

I like to keep the tool engaged as much as I can and ideally not recutting chips.
350 or so sfm, lots of coolant.
I currently use mainly Garr VRX, they've been reliable for my use, good ROI. There's probably better ones out there but I haven't felt like taking the time to search anymore an see if they pan out, I might have to look for another brand soon though as last time it was hard to get what I wanted.

mmurray70 · May 16, 2020

I haven't cut hardly any 316 in past few years, but have a new customer now bringing some 316 parts so I need to get better at it. Machine is a Fadal 4020. For old style machining I usually run 250 SFM and 0.002 FPT, adjust depth based on setup and flute length. This always gets the job done but its slow and hard on tools. One bonus is that only the tip of tool wears. These tools can be reused later for cutting thinner plates.

I've tried a little bit of HSM but cant seem to get it running a whole lot faster. Running 400 SFM and 5% stepover seems to give good tool life. I found tool life goes down fast over 400sfm, seems like it works much better with coolant even though some places say you must run dry at higher speeds. And also seems like stainless works better with even lower width of cut, like 5% vs 10-15. But im still learning when it comes to this HSM stuff on stainless. Hoping to see more examples of what works for others in terms of SFM/Feed/width of cut/etc to see if I can get more efficient. Maybe I just need to be more patient with this stuff and accept that it has to run slow.

mmurray70 · May 16, 2020

ChipSplitter said:
You COULD try using an endmill for titanium. The sharper edge combined with an HEM strategy might give you the life you're looking for.

I have so far successfully managed to stay away from all SS except 303. Am I blessed beyond measure?

I think the sharper edge is very important too. I've always used Kennametal KC433m grade endmills which are nice and sharp and work great. Lately they have been pushing KCPM15 as a replacement and they are complete garbage in my opinion. These new ones have more of a honed edge for steel and they dont last in stainless at all. The 1/8" endmills in this grade wont cut anything. They just crack off because of the honed edge.

Mtndew · May 18, 2020

mmurray70 said:
I haven't cut hardly any 316 in past few years, but have a new customer now bringing some 316 parts so I need to get better at it. Machine is a Fadal 4020. For old style machining I usually run 250 SFM and 0.002 FPT, adjust depth based on setup and flute length. This always gets the job done but its slow and hard on tools. One bonus is that only the tip of tool wears. These tools can be reused later for cutting thinner plates.

I've tried a little bit of HSM but cant seem to get it running a whole lot faster. Running 400 SFM and 5% stepover seems to give good tool life. I found tool life goes down fast over 400sfm, seems like it works much better with coolant even though some places say you must run dry at higher speeds. And also seems like stainless works better with even lower width of cut, like 5% vs 10-15. But im still learning when it comes to this HSM stuff on stainless. Hoping to see more examples of what works for others in terms of SFM/Feed/width of cut/etc to see if I can get more efficient. Maybe I just need to be more patient with this stuff and accept that it has to run slow.

Using a 1/2" 4 flute. variable helix,.03r bullnose, TiALN coating.. I would go 1" deep,5% stepover 496SFPM and .0099 IPT. Which equals about 3788 RPM and 150IPM.

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Better tool life milling 316? HSM??

mmurray70

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TeachMePlease

Diamond

ChipSplitter

Titanium

SND

Diamond

mmurray70

Stainless

mmurray70

Stainless

Mtndew

Diamond

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