Face mills and cooling

[TeleGuy]

Can anyone tell me the proper cooling for a face mill? The 2 HMC's I run do not have any type of cooling at all for the inserts. I was told once that the way we have them now is the correct way to use the face mills. What would happen if we used coolant splashed on the surface we are milling? Thanks!

[Chris D]

On tooling that has an interrupted cut and carbide inserts, it is often best to not use coolant. As the insert enters the cut, it heats up substantially, then during the exit from the cut (where coolant is able to hit the insert) it cools rapidly. This heating and coolant can cause thermal cracking on the inserts resulting in poor performance and life.

This is all assuming you are cutting some form of steel. Aluminum and some other alloys do not causing heating and thus can run wet.

Chris

[5axisguy]

I agree with what Chris said, most coatings like to run hot and are made for use without coolant, I saw some high speed photography on running coolant on carbide milling inserts and the coolant actually vaporized before it got to the cutting edge from the heat. You usually do more harm than good with coolant, one exception is high pressure thru spindle coolant with about 750psi, also some coatings work on stainless and aluminum with coolant.

[fizzissist]

You'll get (usually) much better tool life without coolant doing steels...I too often have to use it because of chips. Carbide inserts really do not like rapid heating/cooling cycles....micro-fracturing leads to catastrophic failure.

If you can get a good air stream to clear chips out, you can really take advantage of the newer carbide insert's ability to hog out material. You don't need the air for cooling, just to clear chips so you don't re-cut.

"Reading" the inserts after they've run awhile can tell you volumes about cutting conditions and where you're at.

[TeleGuy]

Thanks guys that makes a lot of sense, really appreciate your input and time!