Control method of superimposition processing of NC machine tool

A control method of superimposition processing of an NC machine tool, comprising:

• providing at least one tool rest that includes a plurality of tools for performing machine processing to a first workpiece and a second workpiece respectively held on an L spindle and an R spindle that are disposed to face each other, wherein one tool rest in the at least one tool rest is controlled to move at least in a Z-axis direction and an X-axis direction, and includes a first tool as a master-side tool and a second tool as a slave side tool, and the one tool rest is controlled to move at least in a Z-axis direction and an X-axis direction, and the L spindle is fixed in the Z-axis and the X-axis directions, and the R spindle is controlled to move at least in the Z-axis and the X-axis directions;
• providing respective processing programs for performing respective kinds of machine processing by the one tool rest to the first workpiece held on the L spindle or the second workpiece held on the R spindle wherein the processing programs includes a first processing program for machine-processing the first workpiece by the first tool, and a second processing program for machine-processing the second workpiece by the second tool;
• and
• inserting superimposition control program for at least partially performing the superimposition processing in which the second processing program runs while the first processing program is running into the first and second processing programs.