Method and apparatus for creating numerical control machining program and program for causing computer to implement same method

A method of creating, based on shape data of an object to be machined and on grinding allowance data for the shape data, a numerically controlled machining program that has the grinding allowance data reflected in the shape data, the method comprising:

• a step of storing the shape data of the object to be machined and the grinding allowance data;
• a shape data modification step of modifying, based on the grinding allowance data, the shape data, to create shape data having a grinding allowance;
• and
• a step of creating a numerically controlled machining program for the modified shape data,
• wherein the shape data modification step includes a step of determining, when the shape data of the object to be machined is modified to create shape data having a grinding allowance, whether or not an uncut portion due to a tool cutting edge radius remains on an edge line segment adjacent to an edge line for which a grinding allowance is established;
• and of creating, in situations where the uncut portion due to the tool cutting edge radius remains on the edge line segment adjacent to the edge line for which the grinding allowance is established, shape data having a grinding allowance in which an amount of adjustment for eliminating during the remaining uncut portion has been taken into consideration.