Fluid Types The main types of cutting fluids fall into two categories based on their oil content:

Straight oils or neat oils are the oldest class of engineered metal removal fluids. They are composed of a base mineral or petroleum oil and often contain polar lubricants such as fats, vegetable oils, and esters, as well as extreme pressure additives of chlorine, sulfur and phosphorus

Soluble oils (also called Emulsion fluid) are composed of a base of petroleum or mineral oil combined with emulsifiers and blending agents Petroleum or mineral oil combined with emulsifiers and blending agents are basic components of soluble oils (also called emulsifiable oils). The concentration of listed components in their water mixture is usually between 30-85%. Usually the soaps, wetting agents, and couplers are used as emulsifiers, and their basic role is to reduce the surface tension. As a result they can cause a fluid tendency to foam. In addition, soluble oils can contain oiliness agents such as ester, extreme pressure additives, alkanolamines to provide Òreserve alkalinityÓ, a biocide such as triazine or oxazolidene, a defoamer such as a long chain organic fatty alcohol or salt, corrosion inhibitors, antioxidants, etc.

Synthetic fluids (chemical fluids) can be further categorized into two subgroups: true solutions and surface_active fluids.

  • True solution fluids are composed essentially of alkaline inorganic and organic compounds and are formulated to impart corrosion protection to water.
  • Chemical surface_active fluids are composed of alkaline inorganic and organic corrosion inhibitors combined with anionic non_ionic wetting agents to provide lubrication and improve wetting ability. Extreme-pressure lubricants based on chlorine, sulfur, and phosphorus, as well as some of the more recently developed polymer physical extreme-pressure agents can be additionally incorporated in this fluids.

  • Semisynthetics fluids(also called semi_chemical) contains a lower amount of refined base oil (5-30%) in the concentrate. They are additionally mixed with emulsifiers, as well as 30-50% of water. Since they include both constituents of synthetic and soluble oils, characteristics properties common to both synthetics and water soluble oils are presented.

     .3.2 Selection