Abstract: A process for machining edge portions of a ceramic article preform without chipping includes grinding in such consecutive machining steps and machining directions that a chipped portion which results in a machined part of the edge portion in a machining step, is removed by any succeeding. Further, a lastly remaining part of the edge portions of the ceramic article preform is machined in a final step without chipping, thereby enabling the edge portion of the ceramic article preform to be ground without chipping.

Abstract: A process for chucking and machining an elongated cylindrical article made of a ceramic material according to the present invention, comprises the steps of: (1) chucking the elongated cylindrical ceramic article between chuck heads at longitudinally opposite end portions of said ceramic article; (2) holding the elongated cylindrical article between the chuck heads under such a low chucking pressure as allowing the ceramic article to slip inside a driven side chuck head while being kept inside the chuck heads at the opposite end portions, and slipping the ceramic article inside the chuck heads for a given time under rotation of a driving chuck head so that any positional deviation between the location of a center axis passing centers of of the chuck heads and an axis of the ceramic article may be removed due to a self aligning centrifugal action of the ceramic article; (3) raising the chucking pressure of the chuck heads to such a level as required for machining the ceramic article; and (4) then machining a su

Abstract: A method and apparatus for testing a ceramic member applies mechanical stress to the member by application of mechanical force and simultaneously applies thermal stress by creating a temperature gradient in the member by localized heating of a portion thereof. The mechanical stress is impact stress or may be applied by application of a static load to the ceramic member. The method is especially applied to the proof-testing a plurality of ceramic members for quality assurance, particularly engine valve members.