Looking for knowledge on machining using ceramic inserts

Anyone know of a forum about machining using ceramic inserts?
Thanks,
Brett.....

You are going to have to be a bit more specific about your application and tooling.
You are in the right forum/board.

I was hoping to find a ceramic specific site or forum. I feel like if there is a site focused on machining with ceramics (not the machining of ceramics), I would be able to learn a lot more about them faster than on a general forum about all aspects of machining. I am totally new to ceramic inserts, although I have been machining for 40 years. I just tried turning pure Nickel on rocket engines and it was a huge improvement over carbide. Now I want to know more, like what S/F's and DOC others have been able to run in pure Nickel. I was instructed by my Sandvik rep to start out at 800 SFM & .008 IPR with a .040" DOC. I am also concerned about tool pressure. The Nickel is electro-deposited over Copper channels and I was concerned that if there is too much tool pressure it could collapse the Nickel over the channels. I did find (surprisingly) that the T-Land seemed to perform better with less tool pressure than the non-T-land insert. Inserts were round, grade 6061. Cutting up to a 20" diameter on a Mazak 450II-M.
Thanks,
Brett.....

That is quite a specific topic to devote an entire forum to it. Two discussions: 1. "I can't believe how fast I can run these but do I have to?", and 2."These inserts cut this hard shit like butter but how can I make them last for hours/days because my boss is a cheap bastard and won't buy me another one"

Who better to ask questions of, than the tool rep or his engineering team?

Ceramic inserts are used to super finishing operations. Ceramics are harder than carbide but more fragile, so it will not be a good idea using them on interrupted cut, or to deburr heat treated surfaces. The big advantage of ceramics is that you can use very high RPM on the machine with very low feed without burning the tool tip. Ceramics are made most of aluminium oxide.

I was especially impressed with these inserts as there was some slight interruptions on the ends and the insert was successful in cutting through them with no problem. Has anyone had good success with any particular brand/grade? There is a brand called Bidemics by NTK. any experience with this brand?Thanks,Brett.....

Why not talk to greenleaf ?

I'm sure they would recommend feeds and speeds as well as what tooling.

I started using ceramic inserts back in the early or mid-80's for turning high speed steel on an engine lathe. At the time, I think the inserts were simple referred to as: "hot pressed aluminum oxide".

- Speed is your friend
- Dwelling is death
- Interrupted cuts are bad
- Better to take less depth of cut, if in doubt

I still have a handful of the things around in case I need to machine something that's carburized in the engine lathe (only have VMC, not a cnc lathe).

I have never used any of the newer generation silicon carbides, or anything like that.

PM

I have a customer that does electro-plating of pure nickel, and then does post-machining. It is actually pretty mild to machine. It seems to be very soft material, and I would not expect a ceramic insert with a negative t-land & hone to work well in that material. Personally, I'd focus on an insert designed for 300-series stainless steels, with a sharper edge prep, and start there.

I have experience with ceramic inserts, but it's always been with turning hardened steels & cast-irons. Neither material is friendly to sharp cutting edges, and are machine quite well with honed/t-land edge-protection inserts.

I am surprised to hear you've had success turning with ceramic inserts in pure nickel.

ricardo_gt said:

Ceramic inserts are used to super finishing operations. Ceramics are harder than carbide but more fragile, so it will not be a good idea using them on interrupted cut,.

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Modern Machine Shop had a fantastic article on ceramics that helped me a lot from about 15 years ago, but its gone now...

I think the first thing to understand about ceramics is that they are not your standard cutting tool.. They feel like a Lego..
Most of them have a big stupid T-Land on them, so they don't really cut like an endmill or a piece of high speed steel...

So how do you cut metal, with what feels like a piece of plastic, with no sharp edges??? HEAT!!!!!!!!

You are basically plasticizing the metal in front of the cutter, and then wiping it away with the next pass.
If you let it cool down, you've got a problem, if you get TOO HOT, you've got a problem..


Saying that you have a problem with interrupted cuts.... Conventional CUTTING tools, you would slow down..

With a ceramic, you are having problems because in an interrupted cut, there is time for things to cool down..
You need to GO FASTER in an interrupted cut (or milling) to keep the heat up.

In my experience, 90% of the wear on a ceramic comes from entering the cut, and building heat.. So you
want to enter the cut as gently as possible, low DOC, low feed, until you build heat..... Then you want
to stay in the cut.. Ramping back and forth.. The rest comes from DOC notching, so vary the depths of cut..
As you are staying in the cut, you may build too much heat, (molten pile of goo) and you may have to increase
feed and back down the speed...

Totally the opposite of anything you've ever experienced with a normal cutting tool that we all use everyday..
If you would slow down with a conventional tool, speed it up with a ceramic.

I'm also sure there is some new fancy stuff out there that I haven't played with.

Yes, I totally did not anticipate success using Ceramics on pure Nickel. That's why it's been a year of fighting it using carbide until I finally decided to give it a shot....And I was totally blown away!The issue using carbide is the inability to break a chip. No matter which chip breaker, depth of cut or any combination failed to break a chip. After each pass I would spend time with wire cutters or tin snips cutting the chip up into manageable removable sections into the chip hopper. Spent more time pulling chips than I did cutting!With the insert I tried so far, the chip is very manageable and it breaks like a normal chip. I am also using coolant! It would take me two days of fighting the chips in order to complete a part. The part I cut with ceramics took 8 hours!I was hoping to find someone that has tried the Bidemics inserts and their experience.Thanks for everyone's input,Brett......

Greenleaf Global Support - Ceramic Inserts - Category

They developed a "Wisker reinforced" ceramic grade years ago, FWIU It takes
interrupted cuts better.

No way to edit, so adding this linky on grades for what materials:
http://www.greenleafglobalsupport.com/wcsstore/Greenleaf/upload/docs/TBCeramicGradeDesc.pdf

brettallen59 said:

Yes, I totally did not anticipate success using Ceramics on pure Nickel. That's why it's been a year of fighting it using carbide until I finally decided to give it a shot....And I was totally blown away!The issue using carbide is the inability to break a chip. No matter which chip breaker, depth of cut or any combination failed to break a chip. After each pass I would spend time with wire cutters or tin snips cutting the chip up into manageable removable sections into the chip hopper. Spent more time pulling chips than I did cutting!With the insert I tried so far, the chip is very manageable and it breaks like a normal chip. I am also using coolant! It would take me two days of fighting the chips in order to complete a part. The part I cut with ceramics took 8 hours!I was hoping to find someone that has tried the Bidemics inserts and their experience.Thanks for everyone's input,Brett......

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Have you tried any inserts for aluminum? Something with a wicked sharp edge, very high-lubricity coating, and very, very tight chip-breaker?

One insert I'd be willing to try in that material - Walter makes an insert in WSM01? grade I think - with their "HIPIMS" PVD nano coating that blew me away. It comes in a positive insert, but the coating is extremely smooth. What you end up with is an insert with extremely low cutting forces.


I'm not really trying to get you to reinvent the wheel, just a little perplexed that ceramic t-land inserts would perform well in commercially pure nickel.

Would you happen to know the tensile-strength of the material by chance?

Jashley73 said:

Have you tried any inserts for aluminum? Something with a wicked sharp edge, very high-lubricity coating, and very, very tight chip-breaker?One insert I'd be willing to try in that material - Walter makes an insert in WSM01? grade I think - with their "HIPIMS" PVD nano coating that blew me away. It comes in a positive insert, but the coating is extremely smooth. What you end up with is an insert with extremely low cutting forces.I'm not really trying to get you to reinvent the wheel, just a little perplexed that ceramic t-land inserts would perform well in commercially pure nickel.Would you happen to know the tensile-strength of the material by chance?

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Actually, yes. I subscribe to the philosophy that sharp cutting edges which "Shear" and not "push" create less heat and reduce cutting forces out perform honed "stronger" inserts. That was my first "out of the box" effort. I used a Arno brand insert, which was the only insert we found to be successful at my last job turning a proprietary grade of aluminum for a computer housing. It made the best chip, but it was still not able to break it.Cutting on a Mazak QT450II-M, the T-Land insert was generating a 3% spindle load, whereas the non-T land was at 6%. I think I will reach out to the NTK people and see what they think about my application for their Bidemics line. Don't know if I can post links here but I'll try; http://www.ntkcuttingtools.com/product/insert_BIDEMICS_index.htmlThanks,Brett.....

Doug already responded a few times with links to Greenleaf. Their catalog has a whole section dedicated to technical information on the use and application of ceramics. It's one of the most informative technical guides I've seen on the use of ceramics. Contact them...now. They will have good information for Nickel-based alloys.
I once tried a milling application of Hastaloy C-276 (no coolant, cold air only) running at 2,500 sfm. It worked but I was getting premature wear do to machine and fixture condition not very good. The Greenleaf tech rep was by my side while giving it a try.

We highly used ceramic inserts for connecting rod turning bores with light feeds, high speeds and smooth(non intrupted cuts. NTK proved the best of ceramics back in the 70s to 90s. yes conn rods are hard but I forget now how hard...

Ceramics

michiganbuck said:

We highly used ceramic inserts for connecting rod turning bores with light feeds, high speeds and smooth(non intrupted cuts. NTK proved the best of ceramics back in the 70s to 90s. yes conn rods are hard but I forget now how hard...

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Greenleaf s new grade of ceramic is Xsytiin 1 it works very well in interrupted cuts

Craig Gosselin said:

Greenleaf s new grade of ceramic is Xsytiin 1 it works very well in interrupted cuts

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Is that what you sell ?