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AssigneeMesser Griesheim GmbH
InventorsThomas Berger, Henry Cohrt, Heribert Dierkes
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According to a known method for producing a component by means of a powdery starting material, powder is mixed with auxiliaries comprising binding agents, whereby a free-flowing mass is produced. A green body is produced from the mass by means of powder injection moulding. A portion of the auxiliaries is extracted by heating the green body in a container and exposing said body to a stream of solvents. The green body is sintered, whereby the component is produced. The aim of the invention is to enable fast and gentle extraction for releasing green bodies which are produced by means of powder injection moulding. According to the invention, the extraction comprises a heating-up phase during which the temperature of the green body is permanently or gradually increased and the green body is overflown by solvent in the form of a compressed, supercritical treatment gas. An extractor that is suitable for carrying out said method is characterised by a pressure sealed housing that is provided with at least one lateral limiting wall and encloses a treatment chamber for receiving a carrier element which is loaded with a plurality of green bodies. Said housing is provided with a lock-up load and removal opening for the green bodies. Said opening is configured in the lateral limiting wall as a passage for the carrier element.
A method for producing a component from a pulverulent starting material by mixing the powder together with auxiliaries, comprising binders, resulting in the formation of a free-flowing mass, after which a preform is produced from the mass by means of powder injection molding, then some of the auxiliaries are extracted in that the preform is heated in a tank and exposed to a solvent stream, after which the preform is sintered, thus giving rise to the component, characterized in that the extraction comprises a heating-up phase during which the temperature of the preform (14) is continuously or incrementally increased and a solvent in the form of a compressed, supercritical treatment gas flows around the preform (14).
The method according to one of the preceding claims, characterized in that the treatment gas is imparted with a first flow direction, and the treatment gas flows around the preform (14) in the flow direction during the heating-up phase, and in that the flow direction is changed at least once during the course of the heating-up phase.
The method according to one of the preceding claims, characterized in that the treatment duration of the preform (14) is set in the range from one hour to three hours.
The method according to one of the preceding claims, characterized in that propane, nitrous oxide or carbon dioxide are used as the treatment gas.
The method according to one of the preceding claims, characterized in that the preform (14) lies on a carrier made of a porous material during the extraction of the auxiliaries.
Dependencies are inferred from the claim text.