Lubricants are the lifeblood of machine tools. Many industries have machinery which requires large quantities of lubricants. Million tons of lubricants are used by the industrial machine each year. Lubricants may be gaseous, liquid, or solid. Liquid lubricants are the most frequently used of the three kinds. The principal function of the oil lubricant is to extend the life of moving parts operating under many different conditions of speed, temperature, and pressure.
All moving parts on machinery and equipment require lubrication. Lubrication of these moving parts is probably the most important and most frequently performed of all maintenance functions. It is important to remember that different machinery need different type of lubricant oils. The manufacturers of machinery provide guidance on lubrication and maintenance required for their particular machines.
There are a number of commercial lubricants on the market. Many commercial lubricant oils are mixed with various additives that react with the metals to form monolayer contaminants.