Cutting fluids - Role in machining and classification

Around 1883, Taylor's studies on the organization of work and metal cutting were the first to mention the use of soap water for spraying workpieces during machining. As a result, cutting speeds increased by 30 to 40%, and tool sharpening could be spaced out.

Soap water fulfilled the two essential functions required of a cutting fluid today:

• tool and workpiece cooling thanks to water's high thermal mass capacity;

• lubrication of the cut, thanks to the fatty content of the soap.

What's more, soap water was more "wetting" than pure water, but it didn't prevent corrosion and stained parts and machines.

Soap water was replaced by vegetable or animal oils, then by mineral oil emulsions and, finally, by mixtures of mineral oils and fats to which additives were added to give them additional qualities.

The technique for distributing cutting oils was modified. A central tank in each workshop distributed the liquid to the various machines.

Coolants were called cutting oils because, whether soluble or not, they always contained oils and, more often than not, a high percentage of mineral oils.

A new step was taken when cutting fluids were found on the market that no longer contained oil of any kind.

This is why we often use the term cutting fluids, which is more general than cutting oils, in the following.

The new cutting fluids are known as chemical or synthetic fluids, and although they are far from dethroning cutting oils, their tonnage distributed is growing steadily every year.

We are unable to provide precise cutting oil formulas, as each manufacturer maintains its own.

We merely indicate the main classes of these products and their essential constituents.

This study is divided into three parts:

Cutting fluids. Role in machining and classification ;

Cutting fluids. Soluble oils;

[BM 7 066] Cutting fluids. Whole oils.