Program generation device generating program for groove machining by drilling

A program generation device, implemented as a numerical controller, which generates a program for controlling machining of a groove which is performed by machining a plurality of holes on a workpiece, the program generation device comprising:

• a specified value input unit which receives specified values including at least a tool radius, a groove shape including a length of the groove, and a cusp height;
• a hole machining set value calculation unit which calculates at least positions of the plurality of holes based on the specified values;
• a hole machining order calculation unit which calculates a machining order of the plurality of holes based on the specified values and respective values calculated by the hole machining set value calculation unit so that a bias is not generated in a removal stock for a tool, with the tool radius, in machining,
• wherein
• the plurality of holes along the length of the groove are allocated to at least one higher priority group and at least one lower priority group,
• the holes allocated to the higher priority group are machined, in the machining order, by the tool earlier than the holes allocated to the lower priority group, and
• at least one of the holes allocated to the higher priority group is located, along the length of the groove, between two of the holes allocated to the lower priority group;
• and
• a control unit configured to cause the tool to move back and forth along the length of the groove while machining the plurality of holes in accordance with the machining order.