Use of Flood Vs. Mist Coolant With Carbide End Mills

When to use misters or flood coolant depends on the application. When conditions permit, misters are preferred for solid carbide end mills, particularly in high speed machining and finishing operations. As the cutting edges of an end mill go in and out of the cut, the heating and cooling of the edges can cause thermal shock. Misters using cutting oils or coolants are very effective at reducing this effect.
PVD coatings like TiAlN create a thermal barrier, allowing higher operating speeds which dissipates more of the heat with the chip. These coatings are very capable of running in dry or near dry conditions.

Misters also eliminate the cost associated with the disposal and maintenance of cutting fluids, and the contamination of chips.

In heavy roughing operations with high radial depths of cut, the need for chip flushing, work piece temperature control, or when other tooling is involved, flood coolant should be used.