MANUFACTURE OF SETTLE STOOL BRICK FOR ELECTRICAL DISCHARGE MACHINING

摘要

PURPOSE: A method for manufacturing large-sized ceramics like settle stool brick for electrical discharge machining is provided to improve strength during forming and sintering, thereby preventing the cracking by using gel-casting and hydration method. CONSTITUTION: The settle stool brick for electrical discharge machining is manufactured by the following steps of: preparing a slurry containing alumina more than 50vol.% by adding monomers such as 0-20wt.% of meta-acryl amide(or acryl amide) and 0.5-2wt.% of methylene bis-acryl amide to 100wt.% of distilled water, and adding ceramic powder such as alumina; optionally adding at least one selected from dispersant, deaerator and humidifier; adding 1-50wt.% of alumina or Portland cement inducing hydration, a polymerization initiator such as ammonium sulfate, and a catalyst such as ethylene diamine; mixing for 5-30min. and deaerating; pouring the slurry into a mold for forming by polymerization of monomer and hydration; drying; sintering.