Abstract: A numerically controlled machine tool, such as a grinding machine, is capable of machining a workpiece with a precise dimension by measuring a workpiece machining dimension and/or a tool length. According to one aspect of the invention, when the machining operation is provisionally terminated, a machining dimension of the workpiece is measured without dismounting the workpiece from a table. If a machining error is detected, the workpiece is further machined to a target dimension to thus eliminate the machining error. According to another aspect of the invention, the grinding surface of a grinder is subjected to dressing or truing, and the length of the grinder reduced through the dressing or truing is detected to determine the actual length of the grinder. With the known length of the grinder, the feeder amount of the grinder with respect to the workpiece is set for the subsequent machining operation.

Abstract: A numerically controlled machine tool, such as a grinding machine, is capable of machining a workpiece with a precise dimension by measuring a workpiece machining dimension and/or a tool length. According to one aspect of the invention, when the machining operation is provisionally terminated, a machining dimension of the workpiece is measured without dismounting the workpiece from a table. If a machining error is detected, the workpiece is further machined to a target dimension to thus eliminate the machining error. According to another aspect of the invention, the grinding surface of a grinder is subjected to dressing or truing, and the length of the grinder reduced through the dressing or truing is detected to determine the actual length of the grinder. With the known length of the grinder, the feeding amount of the grinder with respect to the workpiece is set for the subsequent machining operation.