US 12,291,656 B2
Production process of polishing stone and polishing stone
Ryogo Maji, Tokyo (JP)
Assigned to DISCO CORPORATION, Tokyo (JP)
Filed by DISCO CORPORATION, Tokyo (JP)
Filed on May 26, 2021, as Appl. No. 17/330,579.
Claims priority of application No. 2020-099136 (JP), filed on Jun. 8, 2020.
Prior Publication US 2021/0380843 A1, Dec. 9, 2021
Int. Cl. C09G 1/02 (2006.01); C03B 19/06 (2006.01); C03B 19/09 (2006.01); C03C 11/00 (2006.01)
CPC C09G 1/02 (2013.01) [C03B 19/06 (2013.01); C03B 19/09 (2013.01); C03C 11/00 (2013.01); C03C 2204/08 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A production process of a polishing stone, comprising:
a glass sphere feeding step of feeding only glass spheres into a mold; and
a firing step of heating the mold with the glass spheres filled therein at a temperature higher than a softening point and lower than a melting point of the glass spheres, thereby forming a glass block as the polishing stone;
wherein, in the firing step, the heating is ended with air bubbles still dispersed and remaining in interstices between the glass spheres;
wherein the glass block after performance of the firing step has a surface roughness (Ra) of 0.2 μm or greater and 1.5 μm or smaller and a porosity of 2% or greater and 8% or smaller; and
wherein the firing step is performed for a period of time such that the heating is ended before the air bubbles are expelled.