18-18 Stainless ?

[c-hook]

Are any of you fellas familiar with machining 18-18. I've never worked with this in my experience, just wondering what sort of feeds/speeds are required for this material. So far it seems pretty tough. We are using various grades and geometry of carbide inserts, and so far nothing has held up too well. Thoughts..................?

 

Thanks for any input.

[chris m]

18-8 is, I believe, 304

 

Are you turning, milling?

 

304 machines, in general, like sh!t when compared to most non-exotic materials

 

If you're turning, I'd suggest starting in the 300SFM range with a good coated carbide insert; moderate depth of cut with a feedrate on the heavy side will keep the heat down and aid in chipbreaking. We run Sandvik here, so I use an MM or MF chipbreaker in a 2015 grade insert for rough and semi-finish turning.

 

Finish turning should be done with cermet inserts to get reasonable tool life, IMO. We use an MF or UF chipbreaker in a 5015 or 525 grade insert for finish turning.

[Odell]

If you are milling, I would look into a Z-Carb-AP from SGS. They are a little pricie side but you get alot of bang for the buck. I have used these to cut 18-8 befor and filled up our VF-4 2 times in one day with one tool.

[Odell]

If you are milling, I would look into a Z-Carb-AP from SGS. They are a little pricie side but you get alot of bang for the buck. I have used these to cut 18-8 befor and filled up our VF-4 2 times in one day with one tool.

[Tim Johnson]

18-18 (18% chromium, 18% nickel) is a little tougher than 316sst (18% chromium, 12% nickel). The extra nickel will make the material more heat resistant and generally tougher to machine. You should be able to run at 70-80% of what you would run 316sst. Keep a good flood on the cutters and if your drilling with hss/cobalt peck very frequently to minimize the heat buildup.

[c-hook]

Thanks gentlemen, I have cut plenty of 316Lss, so that will give me some idea of what to expect. This part, which we are turning, came to us as a forging, and it's about 33" diameter, and about 40" long, so it looks like there will be some considerable cycle time.

[Tim Johnson]

quote:

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From: Looking for my parts in the chip pan

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You must have one hell of a chip pan.

[chris m]

quote:

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came to us as a forging

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Ouch; that's a different story altogether, man. You might want to toughen the insert grade up a little for a forging, or use one tool just to get the skin off and then go at it a little harder in the clean material. Rubbing the tools along that skin is a tool killer, so get under it in one pass wherever you can and watch out for serious DOC notching because of the forged surface.

 

C

[c-hook]

quote:

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You must have one hell of a chip pan.

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They are usually tiny parts......lol.

 

or my eye sight is getting REALLY bad.

[c-hook]

quote:

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Ouch; that's a different story altogether, man. You might want to toughen the insert grade up a little for a forging, or use one tool just to get the skin off and then go at it a little harder in the clean material. Rubbing the tools along that skin is a tool killer, so get under it in one pass wherever you can and watch out for serious DOC notching because of the forged surface.

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I'm hoping things will ease up once we get through the out layer.

[Guest CNC Apps Guy 1]

I like Destiny Raptor 3/6™ Tools. With that material, I'd look in the neighborhood of 250/300 SFM and .0008 ~ .0055 (1/8" ~ 1") IPT for feeds (depending on Dia.)

[j.nguyen]

Most of my stainless parts are forgings and one trick that works really good is conventional milling though the skin, if you have a machine with enough torque. I did this on a part that is quite a bit larger then yours and we machine them 6 at a time. The savings in tool life was huge.

 

X4

[cam do]

Go old school on that puppy. Honed insert with a negative rake holder and like Moffet said, get under the skin.