Control apparatus of machining device and control method of the same

A control method of a machining device processing a first section of a workpiece and a second section in a position which is different from a position of the first section and which is apart from a reference surface of the workpiece in order of the first section and the second section, the machining device including a coolant supply apparatus which supplies a coolant to the second section of the workpiece during processing work, and a temperature detection apparatus which detects a temperature of the coolant, the control method comprising:

• a calculation step of estimating the temperature of the coolant at a time when a predetermined time elapses from a start of the processing work to be a temperature of the workpiece and calculating a deformation amount of the workpiece due to thermal expansion;
• a processing position correction step of correcting a processing position of the second section with respect to the reference surface based on the deformation amount;
• and
• a second section processing step of starting processing of the second section in the corrected processing position after the processing position correction step, wherein
• the predetermined time is a time defined in advance from the start of the processing work until a difference between a temperature of a vicinity of the second section of the workpiece and the temperature of the coolant falls within a predetermined range, and
• the predetermined range of the difference between the temperature of the vicinity of the second section of the workpiece and the temperature of the coolant is within ±1° C.