Method and system for automatic electrical sintering

• Main Author: TOKITA, MASAO
• Format: Patent
• Language: English; French; German
• Published: 14.02.2007
• Subjects: ARTIFICIAL STONE; BLASTING; CASTING; CEMENTS; CERAMICS; CHEMISTRY; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDINGMATERIALS; CONCRETE; DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS,IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KINDOF FURNACE; FURNACES; FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; HEATING; KILNS; LIGHTING; LIME, MAGNESIA; MAKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MECHANICAL ENGINEERING; METALLURGY; OPEN SINTERING OR LIKE APPARATUS; OVENS; PERFORMING OPERATIONS; POWDER METALLURGY; PRESSES; PRESSES IN GENERAL; REFRACTORIES; RETORTS; SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS, SLAG, OR MIXTURESCONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER; SLAG; TRANSPORTING; TREATMENT OF NATURAL STONE; WEAPONS; WORKING CEMENT, CLAY, OR STONE; WORKING METALLIC POWDER

The present invention is a method of automatically loading powder material into a sintering mold and subsequently effecting electrical sintering to the powder material in the sintering mold. The method includes the steps of: fitting a lower press core into a bore formed in the sintering mold, while allowing displacement of the lower press core in the bore; filling different powder materials, which differ from one another in at least one of properties including component(s) of powder material, percentages of components, particle size and particle shape, into the bore to form respective powder layers of the different powder materials in the bore, while displacing the lower press core downward in the bore sequentially and in a stepwise manner, such that the position of a top surface of the lower press core from a top surface of the sintering mold is adjusted depending on the thickness of the respective layers of the different powder materials being filled into the bore; preliminarily pressing at a desired pressure the powder layers of the different powder materials; displacing the pressed powder layers together with the lower press core relative to the sintering mold so as to position the powder layers to a desired position in the sintering mold; fitting an upper press core into the bore of the sintering mold and onto the powder layers; pre-heating to a desired temperature the sintering mold with the powder compact formed therein and with the upper press core fitted therein; and effecting electrical sintering to the powder compact. The last step is carried out by: operating upper and lower conductive members so as to press at a desired pressure the upper press core and the lower press core fitted in the sintering mold having been pre-heated; and simultaneously applying sintering current to the powder layers through the upper and lower conductive members.