Electric discharge machining apparatus

An electric discharge machining apparatus for machining a workpiece by electric discharge machining, the electric discharge machining apparatus comprising:

• temperature sensors respectively attached to an upper portion, a middle portion, and a lower portion of the electric discharge machining apparatus and measuring temperatures of the electric discharge machining apparatus at predetermined time intervals;
• a control device calculating values of temperature environment diagnostic indexes, which are indexes for determining machining accuracy of the workpiece obtained when electric discharge machining is performed in a current temperature environment, from measurement results of the temperature sensors, comparing the values of the temperature environment diagnostic indexes with reference values of the temperature environment diagnostic indexes recommended for achieving desired machining accuracy, and outputting determination results indicating a degree of whether the current temperature environment around the electric discharge machining apparatus is appropriate for achieving the desired machining accuracy according to differences in the comparing;
• and
• a storage part storing the reference values and the determination results,
• wherein the temperature environment diagnostic indexes are indexes comprising temperature and time variables, and comprise at least one of an average reference temperature change range, an average upper and lower temperature difference fluctuation range, and an average reference temperature change rate,
• wherein the average reference temperature change range is an average value of a maximum change range of a reference temperature measured by the temperature sensor attached to the middle portion of the electric discharge machining apparatus in a predetermined period,
• the average upper and lower temperature difference fluctuation range is an average value of a difference between a maximum value and a minimum value of a temperature difference between the temperature measured by the temperature sensor attached to the upper portion of the electric discharge machining apparatus and the temperature measured by the temperature sensor attached to the lower portion of the electric discharge machining apparatus each day in a predetermined period, and
• the average reference temperature change rate is an average value of a maximum change rate of the reference temperature in a predetermined period which is obtained by measuring the maximum change rate of the reference temperature in the predetermined period and then averaging the measured values.