Method for hard fine machining of two toothings on a workpiece, and gear cutting machine, control program, hard fine machining combination tools and sensor assembly therefor

A method for hard finishing two different gears (1, 2) provided on a workpiece (4), said gears each having respective teeth, wherein said gears each have a respective tooth gap being defined by the space between successive ones of the teeth on each of said gears,

• said workpiece being removably held on a rotatable workpiece spindle of a gear hard finishing machine during the hard finishing, wherein said workpiece spindle is rotatable about a workpiece spindle axis, and wherein said two different gears comprise a first gear (1) and a second gear (2), and
• wherein said hard finishing of said first gear (1) is carried out by a first machining process by a first hard finishing tool and said hard finishing of said second gear (2) is carried out by a second machining process by a second hard finishing tool,
• wherein, prior to each of said first and second machining process, to enable tool engagement of said first hard finishing tool with said first gear and engagement of said second hard finishing tool with said second gear for carrying out the respective machining process, a first relative rotational angle position (φ1) of a first rotational position reference (12) of the first gear (1) is detected relative to a position of a marking (3) on said workpiece (4) and relative to a position of said workpiece spindle about the rotational axis of the workpiece spindle, and a second relative rotational angle position (φ2) of a second rotational position reference (22) of the second gear is detected relative to a position of said workpiece spindle about the rotational axis of the workpiece spindle, wherein the first relative rotational angle position (φ1) of the first rotational position reference (12) of the first gear (1) is different from the second relative rotational angle position (φ2) of a second rotational position reference (22) of the second gear (2),
• wherein the first and second machining processes are carried out on the first (1) and second (2) gears, respectively, while the first (1) and second (2) gears are held on said workpiece spindle of said gear hard finishing machine, with no workpiece holding change occurring between said first and second machining processes, and with the difference between the first and second rotational position references defining a relative rotational position of the first gear with respect to a rotational position of the second gear for the first and second machining processes.