Lathe machining with ceramic inserts for Inco 625

[Eric E]

Hello,

I asking for some help to better use ceramic inserts on a Lathe.
If you have experience on how to keep your inserts from chipping and lasting longer, please help me develop a better process. 

It was recommend to me to chamfer or radius into and out of the cut.
I have included a TEST.mcam file. 
I'm and roughing the ID in sections for chips and to check or change insert if needed.

My inserts are not lasting more than one section and is chipping.

 

Thanks

TEST.mcam

[crazy^millman]

The roughing operation is not leading off correctly. The tool is dragging the insert down the faces verse feathering off the back face. To do what you are after you will find it best to use the exit arc. You had it, but as -90 change it to +90. The other thing to consider is the roughing angle of Zero. Might try 45 degrees as the roughing angle.

Excellent job defining your Lathe tool and holder as a 3D tool. 

Is the machine a live tooling lathe? Might think about using a C Axis process with a milling tool. The wear and tear is spread over several teeth not one edge of an insert. I took a 2 hour rough turning cycle on a standard lathe and moved it to a Multus Years ago. I was roughing the same area in 1 minute with a 7 flute endmill. If not then might also think about switching to a button insert verses the 80 degree helps to feather in and out on Inconel better. 

[Eric E]

1 hour ago, crazy^millman said:

The roughing operation is not leading off correctly. The tool is dragging the insert down the faces verse feathering off the back face. To do what you are after you will find it best to use the exit arc. You had it, but as -90 change it to +90. The other thing to consider is the roughing angle of Zero. Might try 45 degrees as the roughing angle.

Excellent job defining your Lathe tool and holder as a 3D tool. 

Is the machine a live tooling lathe? Might think about using a C Axis process with a milling tool. The wear and tear is spread over several teeth not one edge of an insert. I took a 2 hour rough turning cycle on a standard lathe and moved it to a Multus Years ago. I was roughing the same area in 1 minute with a 7 flute endmill. If not then might also think about switching to a button insert verses the 80 degree helps to feather in and out on Inconel better. 

Is it possible to show me on the TEST.mcam file?

I having some issues achieving this in sections and lasting.

 

Thanks

 

[crazy^millman]

Go into the operation and adjust the reaming stock. The issue is Mastercam is adding stock that you don't want the toolpath to use and this is where you have to do a little work to get it to work correctly. 

Here is the file back with all 4 section roughed and I change it to 30 degrees to give you a different way to look at it. I doubt your IT will allow Dropbox link so shoot me an email I gave you in the PM. I shared the file so others can learn from this. 

Dropbox link

[BBprecise]

Not sure if you've got what you needed, but my opinion is stay away from ceramics in Inco 625. Better off with carbide IMHO. We have a few Inco 625 jobs we do and we originally tried ceramics and they didn't hold up for crap. These parts are forgings, but even after we removed the scale and got in to clean smooth cuts they still didn't hold up well. We rough with Kennametal 3/4" round and square inserts. We take 3/8" DOC's at .012 ipr at 120 sfm with KC5010 or Sumitomo AC520U grade inserts. We use same grades for finishing at 150-160sfm.

I have done a lot of programming with ceramics in Inco 718, and a few types of Rene and have very consistent luck with our process. In these materials when roughing we use Kennametal KY1540 inserts at anywhere from 650-750sfm at .007ipr at .125-.150 doc. Now the key is when you go in to a cut and come out. Coming in I bring the insert in at a 45º so it just barely cuts a chamfer and do this for every pass going in to a sharp corner. When ever possible coming out of a cut I create a line at 45º from the surface I'm cutting up to the last surface and wrap a radius to smooth that corner. This way when I come in for the next cut I ramp down to the surface I was just cutting then feed straight into the edge prep from the last cut.

The pic without the tool shows the 45º lead off with a .03-.06r between the 45º line and the last level. The pic with tool is ramping in to the surface I just cut, then it feeds straight in to the 45º lead. This is on a VTL so this is actually boring the ID of a part. I'd have to make a video of a toolpath showing how I bring ceramic inserts into a corner.

Greenleaf used to have a great section in their old catalogs showing how to prep edges for ceramics and best practices, don't know if they still do or not. If not let me know ad I'll send to 20+ pages I have.

What you're trying to accomplish is to move the notch point out of the cutting zone, as this is what causes the highest failure in ceramics. When we rough with ceramics we time the passes so we get roughly 4min's per pass with Ø1/2" button inserts, 3min's roughly with a Ø3/8" buton and so on. Finishing we aim for 5-7 minutes depending on material and brand of ceramic insert. Finishing with Ø1/2" buttons we usually take .05-.075/side. You have to be where the insert is the strongest which the Greenleaf paperwork explains to you,

Cutting Inco 718 and Rene's is like butter for us.

[nickbe10]

21 hours ago, BBprecise said:

Now the key is when you go in to a cut and come out.

Nice...used to do this sort of thing a lot with large Ti  hog-outs (mills) to control the heat build up on the insert edge.

Never had much need for ceramics in Inconel but we tried them in some Incoloy which was just eating our carbide for breakfast.

Turned a 45 min roughing nightmare into a 5 minute cakewalk. Pretty exciting the first part through, too...

[Eric E]

43 minutes ago, nickbe10 said:

 

Thanks Guys,

If you can help out with the TEST-4.mcam (2021) file this would be greatly appreciated.

It may not be the same tool you use but can help with the overall process I'm trying to develop on Inco with ceramic inserts.

BBprecise

Greenleaf used to have a great section in their old catalogs showing how to prep edges for ceramics and best practices, don't know if they still do or not. If not let me know ad I'll send to 20+ pages I have.

Please send me info you can

Thanks for your help

Eric

 

 

TEST-4.mcam

[AMCNitro]

answered the wrong post, sorry

[BBprecise]

On 10/23/2020 at 1:35 PM, Eric E said:

Thanks Guys,

If you can help out with the TEST-4.mcam (2021) file this would be greatly appreciated.

It may not be the same tool you use but can help with the overall process I'm trying to develop on Inco with ceramic inserts.

BBprecise

Greenleaf used to have a great section in their old catalogs showing how to prep edges for ceramics and best practices, don't know if they still do or not. If not let me know ad I'll send to 20+ pages I have.

Please send me info you can

Thanks for your help

Eric

 

 

TEST-4.mcam

I don't have 2021 installed yet so I can't open the file.

On 10/23/2020 at 12:46 PM, nickbe10 said:

Nice...used to do this sort of thing a lot with large Ti  hog-outs (mills) to control the heat build up on the insert edge.

Never had much need for ceramics in Inconel but we tried them in some Incoloy which was just eating our carbide for breakfast.

Turned a 45 min roughing nightmare into a 5 minute cakewalk. Pretty exciting the first part through, too...

Ceramics in 718 haul xxxx. If we needed to hold tight tolerances in 718 we had to use carbide to get the time in cut we needed without the edge's wearing.