PURPOSE: To set many parameters by injecting jet of abrasive powder particles toward the surface of an electric insulating material by limiting areas on which jet is hit and relatively moving jet and the electric insulating material.
CONSTITUTION: A mask 30 having a pattern of a regularly circular aperture is provided on a plate 28 and the mask 30 is mounted on a supporting body 29 of a polishing device 31. Abrasive powder particles are injected toward the mask 30 from a spraying device 32 of the polishing device 31 via a nozzle 33. In this case, a distance between the nozzle 33 and the mask 30 is made about 0.5 to 25 cm and silicon carbide particles of a grain diameter 1 to 200 μm is injected as abrasive powder particles. A spraying device 32 is moved in the direction of an arrow by a horizontally moving device 34, also the nozzle 33 is moved, the plate 28 and the mask 30 are moved together with the supporting body 29 in the direction perpendicular to the arrow and polishing is performed.
LAARHOVEN FRANICSCUS M H VAN (NL)
BEEK JOHANNES GERARDUS VAN (NL)
