Tool wear and tool life are important criteria affecting the part quality. Traditionally there are two methods followed in the industry to determine the end of tool life and to change it. In one case, where the cost of work piece is significant, than the tool is discarded prematurely before its useful life has completed. This saves the costly part from getting damaged. In other case, where cost of the part in not significant, the tool is used till the end of the useful life. Once the tool reaches end of tool life and part quality affected, the tool is changed and the part is either discarded or rework is carried out. Generally industry utilizes past data to determine useful life of tool. There are two ways to know tool wear: Direct and Indirect. Tradionally, tool wear is measured directly using optical microscope which is an offline and time consuming technique. In indirect technique, parameter that is affected by tool wear is measured. Many researchers have selected the parameter like current, force, surface finish, temperature etc. and correlated it with tool wear and tool life.