PURPOSE: To reduce shavings and contrive to reduce the manufacturing cost by a method wherein the outer periphery of a rubber mold, in which ceramic granules are charged, is pressed by working fluid and the resultant compact is taken out by splitting the rubber mold and, after being form-turned, fired.
CONSTITUTION: In order to manufacture the objective cylindrical product having the outer periphery with uneven shape such as the insulator of a vacuum circuit-breaker, firstly, granules 2 are manufactured by mixing ceramic stock powder, paraffin, resin, water and high-purity aluminum powder. The granules 2 are filled in a gap 31, which is produced by fitting a metal pin 4 for forming an axis bore 12 in a bisectional type rubber mold 3 with a mold space having the volume 1.5 times as large as that of the insulator 1. The resultant assembly is arranged in a pressure vessel 5 so as to be applied by the pressure with hydraulic oil 52 in order to be rubber-pressed for ten several sec. After that, the assembly is taken out of the pressure vessel 5 and a compact 6 is taken out of the rubber mold 3 by bisecting the mold. Then, by drawing out the metal pin 4 and inserting a holder 61 instead, the compact 6 under rotation is form-turned with a cutting tool. By firing the form-turned compact 6 under normal pressure, an insulator 1 is completed.
TANAKA SHOZO
ITO TOMIO
