Tool life management system

A tool life management system for managing a tool life, comprising:

• load torque measuring means for measuring an initial load torque of a spindle attached to a tool during an initial machining operation and for measuring an actual load torque of the spindle attached to the tool during a subsequent actual machining operation, by using an observer and excluding a friction torque from a disturbance load torque;
• torque calculating means for calculating a tool wear detection torque based on a reference load torque, and for calculating a tool breakage detection torque based on a tool diameter, the reference load torque being said initial load torque of the spindle;
• a memory for storing the reference load torque, the tool wear detection torque and the tool breakage detection torque;
• torque comparing means for comparing said actual load torque of the spindle with each of the tool wear detection torque and the tool breakage detection torque, and for outputting a result of the comparison;
• and
• tool control means for controlling said tool in accordance with the result of the comparison.