Machining area specifying method for an automatic programming system

An automatic method for specifying a machining path, comprising the steps of:

• (a) providing path blocks, including path data, for defining a closed path trajectory, each of the path blocks having starting point coordinates;
• (b) displaying the closed path trajectory based on the path blocks;
• (c) displaying the cursor at the starting point of a designated path block by using the starting point coordinates;
• (d) providing a first switch for cursor advance and a second switch for cursor back-up;
• (e) advancing the cursor one path block at a time in a tool travelling direction each time the first switch is pressed;
• (f) backing up the cursor one path block at a time in a direction opposite to the tool travelling direction each time the second switch is pressed;
• (g) designating first and second points on the closed path trajectory using the cursor, the first and second points defining the ends of first and second paths on the closed path trajectory;
• and
• (h) selecting one of the first and second paths as a path to be machined by generating a selection signal when the cursor is designating the selected one of the first and second paths, said step (h) including the substeps of:
• (h1) operating a machining area input switch while the first path is being designated by the cursor when the first path is to be machined;
• and
• (h2) operating the machining area input switch while the second path is being designated by the cursor when the second path is to be machined.