A controller of a machine tool determines in accordance with a machining program whether a first tool post is used to machine an unfinished workpiece. When the unfinished workpiece needs machining before terminating a continuous machining and when the controller determines that the first tool post is used to machine the unfinished workpiece W2, the controller simultaneously advances a first system and a second system in accordance with the machining program while preventing machining a workpiece held by the first spindle. When the controller determines that the first tool post is not used to machine the unfinished workpiece, the controller stops the first system and advances the second system in accordance with the machining program.

A control device for a machine tool to produce a plurality of different-shaped products efficiently and successively is provided. In the control device, each driving shaft of modules is assigned to different control systems. The device includes a multi-system program storage part for storing a plurality of multi-system programs to machine a workpiece in different shapes, a multi-system program dividing part for dividing the multi-system programs into machining programs, a divided program storage part for storing the divided machining programs individually, a system-based program storage part for storing the machining programs for the respective control systems, and a machining program selection part for selecting the machining program from the divided program storage part in accordance with the machining step to be executed and for storing the selected machining program in the system-based program storage part for the respective control systems

A control device for a machine tool to produce a plurality of different-shaped products efficiently and successively is provided. In the control device, each driving shaft of modules is assigned to different control systems. The device includes a multi-system program storage part for storing a plurality of multi-system programs to machine a workpiece in different shapes, a multi-system program dividing part for dividing the multi-system programs into machining programs, a divided program storage part for storing the divided machining programs individually, a system-based program storage part for storing the machining programs for the respective control systems, and a machining program selection part for selecting the machining program from the divided program storage part in accordance with the machining step to be executed and for storing the selected machining program in the system-based program storage part for the respective control systems.

For control of a multi spindle machine tool (1), which has a first tool spindle (2a, 2b) and a second tool spindle (2a, 2b) able to be controlled independently thereof, a first workpiece (5a, 5b) and a second workpiece (5a, 5b) are processed by a parts program synchronized in two processing channels being processed. The processing of the parts program includes an activation of first machine axes for guidance of the first tool spindle (2a, 2b) in accordance with a first tool track and the processing of the parts program includes an activation of second machine axes for guidance of the second tool spindle (2a, 2b) in accordance with a second tool track. A processing result of the first workpiece (5a, 5b) at an end of the first tool track is the same as a processing result of the second workpiece (5a, 5b) at an end of the second tool track. The first machine axes and the second machine axes are activated in such a way that a difference in time between reaching the end of the first tool track and reaching the end of the second tool track is less than or equal to a predetermined limit value.