Method for measuring work portion and machining method

A machining method for machining an outer circumferential surface of a cylindrical work portion of a workpiece mounted on a machine tool in accordance with a machining program, the work portion being concentric with a rotation center of the workpiece, the method comprising:

• setting a first distance between a rotation center of the workpiece and a reference point provided on the machine tool;
• rough grinding the workpiece until a rough-grinding end position is met;
• measuring a second distance between the reference point and an outer circumferential surface of the work portion after the rough grinding step;
• obtaining a new diameter of the work portion on the basis of the first and second distances;
• correcting the machining program based on the new obtained diameter of the work portion;
• and
• finish grinding the outer circumferential surface of the work portion in accordance with the corrected machining program.

A work-portion measuring method for measuring a diameter and eccentricity of a cylindrical work portion of a workpiece mounted on a machine tool, the work portion being eccentric with respect to a rotation center of the workpiece, the method comprising:

• setting a first distance between the rotation center of the workpiece and a reference point provided on the machine tool;
• rough grinding the workpiece until a rough-grinding end position is met;
• measuring a second distance between the reference point and an innermost point on an outer circumferential surface of the work portion after the rough grinding step;
• measuring a third distance between the reference point and an outermost point on the outer circumferential surface of the work portion;
• obtaining a new diameter and eccentricity of the work portion on a basis of the first, second, and third distances;
• and
• finish grinding the workpiece based on the new diameter obtained in the obtaining step.

A machining method for machining an outer circumferential surface of a cylindrical work portion of a workpiece mounted on a machine tool in accordance with a machining program, the work portion being eccentric with a rotation center of the workpiece, the method comprising:

• setting a first distance between the rotation center of the workpiece and a reference point provided on the machine tool;
• rough grinding the workpiece until a rough-grinding end position is met;
• measuring a second distance between the reference point and an innermost point on an outer circumferential surface of the work portion after the rough grinding step;
• measuring a third distance between the reference point and an outermost point on the outer circumferential surface of the work portion;
• obtaining a new diameter and eccentricity of the work portion on a basis of the first, second, and third distances;
• correcting the machining program based on the obtained new diameter and eccentricity of the work portion;
• and
• finish grinding the outer circumferential surface of the work portion in accordance with the corrected machining program.