Abstract: To increase precision in straightness on a journal thrust surface relative to an outer peripheral surface of a journal in a crankshaft, a control system is provided for controlling movement of a cutter in axial directions by running a control program transferred from an automatic programming apparatus. The automatic programming apparatus corrects machining data on the basis of data for correcting the straightness gained through a comparison between results of a measurement of machining dimensions of the journal thrust surface in the workpiece on which a cutting process has been carried out and target machining dimensions for the journal thrust surface. A control program is prepared on the basis of the corrected machining data after correction of the machining data.

Abstract: An object is to increase precision in straightness on a journal thrust surface relative to the outer peripheral surface of the journal in a crankshaft, and in the control system for controlling the movement of a cutter in axial directions by running a control program transferred from an automatic programming apparatus, the automatic programming apparatus is provided with a machining data correcting means for correcting machining data on the basis of the data for correcting the straightness gained through comparison between the results of measurement of the machining dimensions of the journal thrust surface in the workpiece on which a cutting process has been carried out in advance and the target machining dimensions for the journal thrust surface; and a program preparing means for preparing a control program on the basis of the corrected machining data after correction of the machining data using this machining data correcting means.

Abstract: A lathe-cutting apparatus and a method with a structure of a chuck being simple, which are capable of lathe-cutting an eccentric part of a crankshaft with high accuracy are provided. For this purpose, the apparatus includes a supporting device (21) for supporting both end portions of a crankshaft (1), a rotational drive device (20) for rotating the crankshaft from at least one end side of the supporting device with a main journal (3) of the crankshaft as a center, and rotationally driving an eccentric part (2), a tool (31) for performing lathe-cutting of the eccentric part, and a cutting tool drive unit (30) for making a cutting edge position of the tool perform crank rotation synchronously with the rotation of the eccentric part which is rotationally driven by the rotational drive device, and performing lathe-cutting of the eccentric part.

Abstract: A lathe-cutting apparatus and a method with a structure of a chuck being simple, which are capable of lathe-cutting an eccentric part of a crankshaft with high accuracy are provided. For this purpose, the apparatus includes a supporting device (21) for supporting both end portions of a crankshaft (1), a rotational drive device (20) for rotating the crankshaft from at least one end side of the supporting device with a main journal (3) of the crankshaft as a center, and rotationally driving an eccentric part (2), a tool (31) for performing lathe-cutting of the eccentric part, and a cutting tool drive unit (30) for making a cutting edge position of the tool perform crank rotation synchronously with the rotation of the eccentric part which is rotationally driven by the rotational drive device, and performing lathe-cutting of the eccentric part.