Machine learning device and method for optimizing frequency of tool compensation of machine tool, and machine tool having the machine learning device

A machine learning device for learning an action value with respect to a change of a tool compensation interval that is a time interval for compensating a tool in a machine tool, the device comprising:

• a state observation unit for observing the tool compensation interval of the machine tool, a processing error amount of a workpiece processed by the machine tool, and a machine working ratio of the machine tool as state variables;
• a learning unit for learning by associating the tool compensation interval, the processing error amount, and the machine working ratio that are observed by the state observation unit with a change amount of the tool compensation interval;
• and
• a decision making unit for determining a change amount of the tool compensation interval based on a result of learning by the leaning unit.