Concentric machining device and method

A method of correcting an eccentricity being the difference between a rotation center and an inner diameter center of a cylindrical body which is to be machined and has an inner diameter and an outer diameter, comprising the steps of:

• (i) mounting the cylindrical body;
• (ii) rotating the cylindrical body at a predetermined angle;
• (iii) photographing a cross-section of the cylindrical body rotating;
• (iv) receiving data of the photographed cross-section and calculating the eccentricity from the data;
• (v) machining the cylindrical body if the eccentricity is 0, and correcting the eccentricity by generating a signal corresponding to the eccentricity and adjusting a position of the cylindrical body if the eccentricity is not 0;
• and
• (vi) repeating steps (ii) to (v) until the eccentricity is 0
• whereby the center of the outer diameter is identical with the center of the inner diameter.

A method for machining a cylindrical body concentric with an axial bore through the body, comprising the steps of:

• mounting a machining object having a bore, in a chuck, with the bore aligned with a rotation axis of the chuck and with a first end of the object facing away from the chuck;
• rotating the chuck and the mounted machining object by rotating a spindle holding the chuck;
• determining concentricity by measuring a rotation path of a center of the bore at the first end of the machining object;
• when the determined concentricity is not equal to zero, adjusting horizontal and vertical positions of the chuck in the spindle, to make the concentricity equal to zero;
• when the concentricity is equal to zero, machining an outer surface of the object and then removing the machined object from the chuck.

A concentric machine device, comprising:

• a chuck for holding one end of a machining object having a central bore;
• a spindle for holding the chuck, said spindle comprising:
• a horizontal piezoelectric ceramic between the chuck and the spindle, for adjusting the position of the chuck in a horizontal direction;
• a vertical piezoelectric ceramic between the chuck and the spindle, for adjusting the position of the chuck in a vertical direction;
• and
• a rotating brush contact point for inputting signals to the piezoelectric ceramics;
• a motor for rotating the chuck;
• a polishing tool mounted in position to machine an outer surface of the machining object;
• a camera mounted along a rotation axis of the spindle facing an end of the machining object opposite the chuck;
• a controller connected to the camera and the rotating brush contact point, for determining a concentricity of the rotation of center of the bore and generating a control signal to the rotating brush contact points.