METHOD FOR PRODUCING AN ADDITIVELY MANUFACTURED ITEM AND DEVICE FOR ADDITIVE MANUFACTURING

Abstract

A method for producing an additively manufactured article (R), comprising: a predetermined layer formation step (S1) of forming a predetermined layer as one of metal layers (507) by irradiating a powder bed (PB) of a metal material with a light beam (L); a surface temperature determination step (S3) of determining the surface temperature of an additively manufactured intermediate product (S) resulting from the predetermined layer formation step; a judgment step (S4) of judging whether the additively manufactured intermediate product is in a superheated state, wherein the additively manufactured intermediate product is judged not to be in a superheated state if the surface temperature is not higher than a predetermined threshold value indicating a superheated state of the additively manufactured intermediate product;and a powder bed forming step (S5) of forming the powder bed on the predetermined layer when the additively manufactured intermediate product is judged not to be in the overheated state as a result of the judging in the judging step; wherein the surface temperature is the surface temperature of a part where heat tends to accumulate, the part being predetermined at least based on the structure of an additively manufactured article (R) to be manufactured and including at least a part of the predetermined layer under which a cavity exists or a part having a cross-sectional area not larger than a predetermined area, the cross-sectional area being along a moving direction of the light beam during additive manufacturing.

Claims

[1] Method for producing an additively manufactured article (R), comprising: a predetermined layer forming step (S1) of forming a predetermined layer as one of metal layers (507) by irradiating a powder bed (PB) of a metal material with a light beam (L); a surface temperature determination step (S3) of determining the surface temperature of an additively manufactured intermediate product (S) resulting from the predetermined layer formation step; a judging step (S4) of judging whether the additively manufactured intermediate product is in the overheated state, wherein the additively manufactured intermediate product is judged not to be in the overheated state if the surface temperature is not higher than a predetermined threshold value indicating an overheated state of the additively manufactured intermediate product; and a powder bed forming step (S5) of forming the powder bed on the predetermined layer when the additively manufactured intermediate product is judged not to be in the overheated state as a result of the judging in the judging step; wherein the surface temperature is the surface temperature of a part in which heat tends to accumulate, the part being predetermined at least based on the structure of an additively manufactured article (R) to be manufactured and including at least a part of the predetermined layer under which a cavity exists or a part having a cross-sectional area not larger than a predetermined area, the cross-sectional area being along a direction of movement of the light beam during additive manufacturing. [2] A method of manufacturing an additively manufactured article according to claim 1, further comprising: a further temperature determination step (S7) of determining the temperature of a supporting element (51) which supports the irradiated powder bed (PB) and the resulting additively manufactured intermediate product (S), wherein in the assessment step (S4), the additively manufactured intermediate product is assessed as not being in an overheated state if the difference between the surface temperature and the temperature of the supporting element is not greater than the predetermined threshold value. [3] A method for manufacturing an additively manufactured article according to claim 1, further comprising a waiting step (S62) of waiting until the additively manufactured intermediate product (S) returns to a non-overheated state when the additively manufactured intermediate product is judged to be in the overheated state in the judging step (S4). [4] A method for manufacturing an additively manufactured article according to claim 3, wherein the waiting step (S62) is performed while powder (P) of the metal material to be supplied onto the predetermined layer in a receiving portion (50) receiving the additively manufactured intermediate product (S) is held on the receiving portion side. [5] A method for manufacturing an additively manufactured article according to claim 4, wherein the waiting step (S62) includes: a movement start step (S631), after the additively manufactured intermediate product (S) has been judged to be in the overheated state in the judging step (S4), of starting the movement of a powder supply mechanism (70) that supplies the powder (P) of the metal material to the receiving section (50) that receives the additively manufactured intermediate product; and a feeding step (S633) of feeding the powder by the powder feeding mechanism onto the predetermined layer in the receiving section after the powder feeding mechanism starts to be moved and the additively manufactured intermediate product is judged not to be in the overheated state. [6] A method for manufacturing an additively manufactured article according to claim 5, wherein the moving speed of the powder feeding mechanism (70) is determined based on the difference between the detected surface temperature and the predetermined threshold value. [7] A method for manufacturing an additively manufactured article according to claim 1, further comprising a cooling step (S61) of cooling the additively manufactured intermediate product (S) to reduce the surface temperature during at least a part of the period from the evaluation step (S4) to the powder bed forming step (S5). [8] A method for manufacturing an additively manufactured article according to claim 7, wherein the cooling (S61) is performed by cooling at least one of the side wall of the accommodating portion (50) accommodating the metal material and the additively manufactured intermediate product (S) or a member (51) supporting the additively manufactured intermediate product. [9] A method for manufacturing an additively manufactured article according to claim 8, wherein the cooling (S61) is performed by a cooling mechanism (52) provided for at least one of the side wall or the supporting member, and the cooling mechanism includes at least one of a water cooler, an air cooler, or a heat sink. [10] A method for manufacturing an additively manufactured article according to claim 1, wherein the predetermined threshold value is set differently for each of the plurality of metal layers (507) in the additively manufactured intermediate product (S). [11] A method for manufacturing an additively manufactured article according to claim 1, further comprising a roughness determining step (S8) of determining the roughness by taking an image of the surface of the additively manufactured intermediate product (S) while irradiating the surface of the additively manufactured intermediate product with light, wherein in the judging step (S4), the additively manufactured intermediate product is judged not to be in the overheated state when the surface temperature at the position where the roughness determined by the roughness determining step is caused is not higher than the predetermined threshold. [12] A method for manufacturing an additively manufactured article according to claim 1, comprising a notification step (S64) in which a notification is generated when the additively manufactured intermediate product (S) is judged to be in the overheated state in the judging step (S4) and the period of time during which the additively manufactured intermediate product remains in the overheated state exceeds a predetermined time. [13] Additive manufacturing facility comprising: a device main body (100) that irradiates a powder bed (PB) of a metal material with a light beam (L) to form a predetermined layer (507) as a metal layer; a temperature sensor (13) which determines the surface temperature of an additively manufactured intermediate product (S) resulting from the formation of the metal layer; and a controller (200), wherein the controller contains: a judging unit (21) that judges whether the additively manufactured intermediate product is in the overheated state, wherein the additively manufactured intermediate product is judged not to be in the overheated state if the surface temperature is not higher than a predetermined threshold value indicating an overheated state of the additively manufactured intermediate product; and a build-up controller (22) which controls the device so that the powder bed is formed on the predetermined layer when the additively produced intermediate product is judged not to be in the overheated state as a result of the judgment by the judgment unit; wherein the surface temperature is the surface temperature of a part in which heat tends to accumulate, the part being predetermined at least based on the structure of an additively manufactured article (R) to be manufactured and including at least a part of the predetermined layer under which a cavity exists or a part having a cross-sectional area not larger than a predetermined area, the cross-sectional area being along a direction of movement of the light beam during additive manufacturing.

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