Method and machine for manufacturing pieces made of ceramic or metallic material by the technique of additive manufacturing

A method for manufacturing at least one piece made of at least one material selected from the ceramic materials and the metallic materials using the technique of additive manufacturing, said one or more pieces being formed in the green state, and then subjected to debinding and sintering operations, said method comprising the following steps:

• (1) building, by computer-aided design, a computer model of the piece to be manufactured or of the pieces to be simultaneously manufactured;
• (2) forming, on a working tray, said one or more pieces to be manufactured, which are based on a ceramic or metallic photocurable composition (CPC or MPC) comprising:
• a mineral part consisting of at least one powdered ceramic material or at least one powdered metallic material;
• and
• an organic part able to be destroyed by heating during the debinding, and comprising at least one photocurable monomer and/or oligomer and at least one photoinitiator,
• the method comprising:
• selecting a CPC or MPC having the consistency of a suspension able to flow in order to form a layer;
• preparing a sacrificial organic material (SOM) able to form a photocurable layer and to be destroyed by heating during the debinding, said SOM comprising at least one photocurable monomer and/or oligomer and at least one photoinitiator;
• for the building of said one or more pieces, on the working tray, forming successive layers of SOM which are stacked on each other, each layer of SOM being caused to cure by irradiation before applying the next layer, the one or more properly speaking pieces based on CPC or MPC being built by:
• forming, by machining, at least one recess in at least one layer of cured SOM from the upper surface thereof;
• depositing, within said one or more recesses, the CPC or MPC in order to fill the one or more recesses;
• curing, by irradiation, the CPC or MPC located within said one or more recesses in order to obtain a hard horizontal surface having the same level as the adjacent layer of cured SOM,
• wherein when forming each recess, the latter is delimited according to the one or more patterns previously defined from the computer model, and the depth(s) thereof selected in order to ensure the continuity of the piece(s) to be manufactured, and
• obtaining, once the cured layers are stacked, one or more green pieces embedded in the SOM, such green pieces being subjected to a debinding by heating in order to destroy the SOM in which it is trapped or they are trapped, so as to release it or them and then submit it or them to a sintering.