Numerical control device

A numerical control device configured to stop machining operation safely before designated time arrives, when the designated time to stop the machining operation is designated, during the machining operation performed by controlling a machine based on machining program, the numerical control device comprising:

• a stop time input unit configured to receive the designated time;
• a machining time prediction unit configured to predict machining time of the machining program considering order to execute blocks of the machining program and time for acceleration and deceleration by a drive unit of the machine;
• an operation stop block designation unit configured to predict an executing block of the machining program at the designated time, predicted to being executed at the designated time, based on the machining time of each block of the machining program predicted by the machining time prediction unit, and designate a stop block for the machining operation to be safely stopped, by searching from the executing block at the designated time in reverse order to the order to execute blocks of the machining program;
• and
• a program operation control unit configured to control to stop the machining operation at the stop block designated by the operation stop block designation unit.