Numerical control apparatus

A numerical control apparatus for measuring a tool length and a workpiece by a skip function, comprising:

• memory means for storing a time constant used when a feed speed of a workpiece is accelerated or decelerated and for storing a machining program;
• skip signal sensing means for determining a present position of said workpiece in response to a skip signal output from a sensing device and for outputting a skip completion signal, said memory means storing said present position in a predetermined region;
• acceleration/deceleration distribution means for outputting a first interpolation pulse for accelerating or decelerating the feed speed of the workpiece based on said time constant and said present position in response to said skip completion signal and for outputting a distribution completion signal after said workpiece moves to an end position commanded in a present block of said machining program;
• and
• preprocessing distribution means for determining an amount of movement of a next block of said machining program from the present position of said workpiece in response to said skip completion signal, for preprocessing the next block of said machining program and for outputting a second interpolation pulse for accelerating or decelerating the feed speed of the workpiece based on said preprocessing of the next block in response to said distribution completion signal.