I am testing out running a ceramic finishing insert on my Mazak qt30.
The diameter of the part is 87mm or 3.425in
SFM suggested was 2500
RPM 2790
Feedrate is F0.016
Depth of cut is 2-3mm on the diameter
I am currently getting a surface that is not smooth. If you rub your thumb across the surface you can feel that it is rough. Now I have never ran ceramics before so I am not sure as to what to change. I have tried up the feedrate to F0.02 but it didn't seem to change the surface. I do know that I don't run coolant with this insert.
Any help would be greatly appreciated.
NorthMachinist
Just saw your post NorthMachinist so I'm not sure if this is too late. Without knowing the insert geometry, ceramic grade, material and material hardness (Ceramic Inserts are designed for Heat Treated Steels, Hear Resistant Alloys and Gray Cast Iron) it is difficult to know exactly what the issue is but from the sound of the rough finish I would lean to the feed rate being off. The .016" IPR feed rate is extremely fast for a Ceramic Insert, here is the feed rate range I generally recommend for Ceramic Inserts:
.002"-.006" IPR
Ceramic Inserts are designed for Heat Treated Steels (45 Hrc+), Hear Resistant Alloys and Gray Cast Iron. If you aren't seeing the finish you are looking for with the feed rate above then we could make an insert grade recommendation that would (would just need to know insert geometry, material and material hardness to make a recommendation). If you are running it in steel below 45 HRc then a Cermet insert would be the best way to go (it would give you the best finish possible). Hopefully this helps!