Patent ID: 7624505

Claim:
Method for operating a machine tool ( 1 ) for tooth-machining of workpieces ( 3 ), wherein the machine tool ( 1 ) has a rotary holder ( 2 ) which is rotatable about a main axis (HA) and which has two workpiece spindles ( 11 , 12 ) whose spindle axes extend parallel to the main axis (HA), wherein the spindle axes are each at the same distance from the main axis (HA), wherein the rotary holder ( 2 ) is rotatable into a first rotated position (VP 1 ) in which the first workpiece spindle ( 11 ) is in a transfer position (TP) and the second workpiece spindle ( 12 ) is in a machining position (BP), and wherein the rotary holder ( 2 ) is rotatable into a second rotated position (VP 2 ) in which the first workpiece spindle ( 11 ) is in the machining position (PB) and the second workpiece spindle ( 12 ) is in the transfer position (TP), characterised by the following steps: a) the rotary holder ( 2 ) is brought into the first rotated position (VP 1 ), at the first workpiece spindle ( 11 ), in the transfer position (TP), a finished part (FT) is unloaded and an unmachined part (RT) is loaded, and at the second workpiece spindle ( 12 ), in the machining position (BP), a semi-finished part (HFT) is produced from an unmachined part (RT) by pre-milling; b) the rotary holder ( 2 ) is brought into the second rotated position (VP 2 ), at the first workpiece spindle ( 11 ), in the machining position (BP), a semi-finished part (HFT) is produced from the unmachined part (RT) by pre-milling, and at the second workpiece spindle ( 12 ), in the transfer position (TP), a deburred chamfered semi-finished part (aHFT) is produced from the semi-finished part (HFT) by chamfering and cutting; c) the rotary holder ( 2 ) is brought into the first rotated position (VP 1 ), at the first workpiece spindle ( 11 ), in the transfer position (TP), a deburred chamfered semi-finished part (aHFT) is produced from the semi-finished part (HFT) by chamfering and cutting, and at the second workpiece spindle ( 12 ), in the machining position (BP), a finished part (FT) is produced from the deburred chamfered semi-finished part (aHFT) by fine-milling; d) the rotary holder ( 2 ) is brought into the second rotated position (VP 2 ), at the first workpiece spindle ( 11 ), in the machining position (BP), a finished part (FT) is produced from the deburred chamfered semi-finished part (aHFT) by fine-milling, and at the second workpiece spindle ( 12 ), in the transfer position (TP), the finished part (FT) is unloaded and an unmachined part (RT) is loaded; wherein steps a) to d) are repeated at least once.