Numerical control device for a machine tool

A numerical control device for a machine tool including working means for machining a workpiece to a target form and dimensions, and measurement means for effecting on-machine measurements of the machined workpiece without changing a position of the workpiece on the machine tool, said numerical control device comprising:

• measurement programming means for generating a measurement program for controlling a measurement procedure of said measurement means;
• working error calculation means, connected to an output of said measurement means, for determining a working error of form and dimensions as measured by said measurement means with respect to a target form and dimensions as provided by said numerical control device to said machine tool, said working error calculation means judging whether said working error is within a tolerance range or not, and when said working error is judged outside of the tolerance range, whether the working eror is such that a correction re-working of the workpiece is possible or not;
• and
• correction re-working programming means for generating a correction re-working program when said working error is outside of the tolerance range and a correction re-working of the workpiece is judged possible, said correction re-working program controlling said working means in a re-working procedure by which the form and dimensions of the workpiece are corrected to the target form and dimensions.