Coolant fluids. Neat oils

Cutting oils are a key factor in the production of mechanical components through machining. In many situations, given the stringent quality and productivity requirements, cutting oils are an indispensable tool for helping machinists become more competitive. Optimizing the service life of cutting tools through the optimal choice of cutting fluid is also a factor in technical and economic gains. Machined components also benefit from the use of cutting oils, particularly in terms of their durability in service. Although essential, cutting fluids are not always used, and there is at least one scenario in which they are not desirable. Spheroidal graphite cast irons are made of free carbon, which greatly facilitates their machining by acting as a solid lubricant under the effect of the heat generated during the material removal process. Readers are invited to consult article [M 4 611] on spheroidal graphite cast irons.

The term "lubrication" was chosen when machining operations were performed at low cutting speeds. Therefore, to overcome the problem of built-up edge formation occurring at low cutting speeds, neat oil was used to prevent the machined material from welding to the cutting tool. This era is now largely over (except for the example illustrated below), but the term has remained. Although industrial production techniques and technologies have evolved considerably, "fluidic" assistance remains necessary, particularly for chip removal, cooling of the cutting zone, optimization of the friction coefficient, etc.

In doing so, it may now be preferable to refer to "cutting fluid."

To gain the best possible understanding of the content of this article, readers are invited to read the article [BM 7 063] .

Derived from polycyclic aromatic hydrocarbons (PAHs), whole oils mainly have lubricating properties. This property is essential in the context of tool/workpiece friction. Due to their high lubricating power, they reduce the coefficient of friction at the tool/material interface, optimizing the sliding between these two components. As a result, this generates better thermal balance in the cutting zone and reduces abrasion/adhesion wear on the tool. In practical terms, this translates into optimized tool life. An underlying effect is that neat oils also reduce machine energy consumption, thanks to the optimization of the friction coefficient, better heat control in the cutting zone, and slower wear of the cutting tool.

PAHs are chemical contaminants formed as a result of the incomplete combustion of organic products. These molecules are toxic to humans: some PAHs are carcinogenic and genotoxic.

...