Machining time calculating apparatus

A machining time calculating apparatus which calculates a machining time when a numerical control apparatus having an interpolation algorithm for adjusting a feed velocity and an acceleration/decleration executes a part program and drives a numeric control machine tool is driven and controlled based on a part program to machine a part, the machining time calculating apparatus comprising:

• a parameter storing unit which stores a parameter to be used when a numeric control apparatus drives and controls the numeric control machine tool;
• a program interpretation unit which reads and interprets the part program to generate machining data for each block;
• an interpolation unit which determines whether or not the machining data for a block is an axis moving instruction and, when the machining data is an axis moving instruction, interpolates a shape instructed in the block by sequentially calculating an amount of axis movement and determining an interpolating point for each control period referring to a parameter stored in the parameter storing unit and using an interpolation algorithm which is identical to a driving and controlling interpolation algorithm of the numeric control apparatus;
• an interpolation count counting unit which counts an interpolation calculation count for each block instructed by the axis moving instruction;
• and
• an axis moving time calculating unit which multiplies an interpolation cycle when the numeric control apparatus drives and controls the numeric control machine tool and the counted interpolation count to calculate an axis moving time of the axis moving instruction.