Process and apparatus for chucking and machining an elongated cylindrical article made of a ceramic material

An apparatus for chucking and machining an elongated cylindrical article made of a ceramic material, said apparatus comprising:

• a pair of chuck heads for chucking longitudinally opposite end portions of the elongated cylindrical ceramic article;
• an applicator for applying a given chucking pressure upon the chuck heads;
• a switch for switching the chucking pressure;
• a driving unit for rotating the chuck heads;
• and
• a machining tool for machining the elongated cylindrical ceramic article chucked by the chuck heads;
• wherein the chucking pressure-switching switch is switched;
• the elongated cylindrical ceramic article is held between the chuck heads under such a given low chucking pressure as to enable the ceramic article to slip within a driven side chucking head and the driving side chuck head is rotated to slip the elongated cylindrical ceramic article within at least the driven side chuck head so that any positional deviation between a location of a center axis passing centers of the chuck heads and a axis location of the elongated cylindrical ceramic article within the chuck heads may be removed;
• then the chucking pressure is raised to a given higher chucking pressure required for machining;
• and in this state a surface of the elongated cylindrical ceramic article is machined by the machining tool.