EP-4741082-A1 - INFORMATION PROCESSING APPARATUS, DEFECT DETECTION METHOD, AND THREE-DIMENSIONAL POWDER BED FUSION ADDITIVE MANUFACTURING APPARATUS

EP4741082A1EP 4741082 A1EP4741082 A1EP 4741082A1EP-4741082-A1

Abstract

An information processing apparatus includes: a defect candidate specifying unit (72) that detects a defective portion generated in a layer as a defect candidate for each layer on the basis of layer data taken for a corresponding layer on which a manufactured object is manufactured by powder bed fusion additive manufacturing (PBF-AM) and specifies a plurality of defect candidates at positions substantially identical to each other in a plurality of layers adjacent in a layering direction; and a defect detection unit (73) that detects, on the basis of a size in the layering direction and a size in the layer of the plurality of defect candidates specified in the plurality of layers at positions substantially identical to each other, a defect remaining in the manufactured object.

Inventors

TSUTAGAWA, NARI
KANEKO, YUHEI
ASANUMA, YUJI
TSUDA, TAKASHI
Suwa, Kento
Ohara, Shuma
SHIBATA, KOHEI

Assignees

Jeol Ltd.

Dates

Publication Date: 20260513
Application Date: 20251030

Claims (18)

An information processing apparatus comprising: a defect candidate specifying unit (72) configured to detect, on a basis of layer data obtained for a corresponding layer on which a manufactured object is manufactured by powder bed fusion additive manufacturing (PBF-AM), a defective portion generated in the layer as a defect candidate for the corresponding layer and specify a plurality of the defect candidates at positions substantially identical to each other in a plurality of the layers adjacent in a layering direction; and a defect detection unit (73) configured to detect, on the basis of a size in the layering direction and a size in the layer of the plurality of defect candidates at positions substantially identical to each other specified in the plurality of layers, a defect remaining in the manufactured object.
The information processing apparatus according to claim 1, wherein the defect candidate specifying unit (72) measures, among the plurality of defect candidates overlapping in the plurality of layers adjacent in the layering direction, an area of a defect candidate of an N-th layer (N is an integer of 1 or more) specified by the N-th layer and an area of a defect candidate of an (N+1)-th layer specified by the (N+1)-th layer, calculates an overlapping area of an overlapping portion where the defect candidate of the N-th layer and the defect candidate of the (N+1)-th layer overlap in the layering direction, and specifies, in a case where a ratio of the overlapping area to the area of the defect candidate of the N-th layer is equal to or larger than a first area threshold and a ratio of the overlapping area to the area of the defect candidate of the (N+1)-th layer is equal to or larger than a second area threshold, that the defect candidate of the N-th layer and the defect candidate of the (N+1)-th layer are at the positions substantially identical to each other.
The information processing apparatus according to claim 2, wherein the defect detection unit (73) integrates the plurality of defect candidates being at positions substantially identical to each other in the layering direction, and measures a layering direction length (Lz) of the integrated defect candidates and a first direction length (Lx) and a second direction length (Ly) in the layer intersecting the layering direction of the integrated defect candidates for the corresponding layer, and sets a length of maximum among the first direction length (Lx) and the second direction length (Ly) as a maximum layer length (Lxy) .
The information processing apparatus according to claim 3, wherein the defect detection unit (73) sets a longer length among the layering direction length (Lz) and the maximum layer length (Lxy) as a maximum length, and detects the integrated defect candidates as the defect in a case where the maximum length exceeds a maximum length threshold.
The information processing apparatus according to claim 3, wherein the defect detection unit (73) sets a longer length among the layering direction length (Lz) and the maximum layer length (Lxy) as a maximum length, and detects the integrated defect candidates as the defect in a case where the maximum length is the layering direction length (Lz) and the layering direction length (Lz) exceeds a maximum length threshold in the layering direction, or the maximum length is the maximum layer length (Lxy) and the maximum layer length (Lxy) exceeds a maximum layer length threshold in the layer.
The information processing apparatus according to claim 3, wherein the defect detection unit (73) prepares a plurality of the maximum length thresholds in the layering direction and the maximum layer length thresholds in the layers, and detects the integrated defect candidates as the defect in a case where the maximum layer length (Lxy) in the layer corresponds to a range defined by the maximum layer length threshold and the layering direction length (Lz) exceeds the maximum length threshold associated with the maximum layer length thresholds.
The information processing apparatus according to claim 1, wherein the defect candidate specifying unit (72) measures, among the plurality of defect candidates overlapping in the plurality of layers adjacent in the layering direction, an area of a defect candidate of an N-th layer (N is integer of 1 or more) specified by the N-th layer and an area of a defect candidate of an (N+1)-th layer specified by the (N+1)-th layer, calculates an overlapping area of an overlapping portion where the defect candidate of the N-th layer and the defect candidate of the (N+1)-th layer overlap in the layering direction, and specifies, in a case where the overlapping area is equal to or larger than an overlapping portion area threshold, that the defect candidate of the N-th layer and the defect candidate of the (N+1)-th layer are at the positions substantially identical to each other.
The information processing apparatus according to claim 2, wherein the defect detection unit (73) integrates the plurality of defect candidates being at the positions substantially identical to each other in the layering direction, and measures a layering direction length (Lz) of the integrated defect candidates and a first direction length (Lx) and a second direction length (Ly) in the layer intersecting the layering direction of the integrated defect candidates for a whole of the integrated defect candidates correspondingly, and sets a length of maximum among the first direction length (Lx) and the second direction length (Ly) as a maximum layer length (Lxy).
The information processing apparatus according to claim 8, wherein the defect detection unit (73) sets a longer length among the layering direction length (Lz) and the maximum layer length (Lxy) of the integrated defect candidates as a maximum length, and detects the integrated defect candidates as the defect in a case where the maximum length exceeds a maximum length threshold.
The information processing apparatus according to claim 8, wherein the defect detection unit (73) sets a longer length among the layering direction length (Lz) and the maximum layer length (Lxy) as a maximum length, and detects the integrated defect candidates as the defect in a case where the maximum length of the integrated defect candidate is the layering direction length (Lz) and the layering direction length (Lz) exceeds a maximum length threshold in the layering direction, or the maximum length is the maximum layer length (Lxy) and the maximum layer length (Lxy) exceeds a maximum layer length threshold in the layer.
The information processing apparatus according to claim 3, wherein the defect detection unit (73) prepares a plurality of the maximum length thresholds in the layering direction and the maximum layer length thresholds in the layers, and detects the integrated defect candidates as the defect in a case where the maximum layer length (Lxy) in the layer of the integrated defect candidates corresponds to a range defined by the maximum layer length threshold and the layering direction length (Lz) of the integrated defect candidates exceeds the maximum length threshold associated with the maximum layer length thresholds.
The information processing apparatus according to claim 1, wherein the defect candidate specifying unit (72) calculates, among the plurality of defect candidates overlapping in the plurality of layers adjacent in the layering direction, an accuracy index of an overlapping portion in which an N-th layer defect candidate specified by an N-th layer (N is integer of 1 or more) and an (N+1)-th layer defect candidate specified by an (N+1)-th layer overlap in the layering direction, and specifies, in a case where the accuracy index equal to or larger than an accuracy index threshold, that the defect candidate of the N-th layer and the defect candidate of the (N+1)-th layer are at the positions substantially identical to each other.
The information processing apparatus according to claim 12, wherein the defect detection unit (73) detects the plurality of defect candidates being at the positions substantially identical to each other continuously over a plurality of layers equal to or larger than the layering threshold as defects.
The information processing apparatus according to claim 3, wherein the defect detection unit (73) prepares a layering direction length threshold and a maximum layer length threshold in the layers, and detects the integrated defect candidates as the defect in a case where the layering direction length (Lz) of the integrated defect candidates is equal to or larger than the layering direction length threshold, and the maximum layer length (Lxy) in the layer of the integrated defect candidates is equal to or larger than the maximum layer length threshold.
The information processing apparatus according to claim 3, wherein the defect detection unit (73) prepares a layering direction length threshold and a maximum layer length threshold in the layers, and detects the integrated defect candidates as the defect in a case where the layering direction length (Lz) of the integrated defect candidates is equal to or larger than the layering direction length threshold, or the maximum layer length (Lxy) in the layer of the integrated defect candidates is equal to or larger than the maximum layer length threshold.
The information processing apparatus according to any one of claims 1 to 15, wherein processing of the defect candidate specifying unit (72) and processing of the defect detection unit (73) are executed in a middle of PBF-AM processing or after the PBF-AM processing.
A defect detection method performed by a defect candidate specifying unit (72) and a defect detection unit (73) included in an information processing apparatus, the defect detection method comprising: a step in which, on a basis of layer data obtained for a corresponding layer on which a manufactured object is manufactured by powder bed fusion additive manufacturing (PBF-AM), the defect candidate specifying unit (72) configured to detect a defective portion generated in the layer as a defect candidate for the corresponding layer and specify a plurality of the defect candidates at positions substantially identical to each other in a plurality of the layers adjacent in a layering direction; and a step in which the defect detection unit (73) configured to detect, on the basis of a size in the layering direction and a size in the layer of the plurality of defect candidates at the positions substantially identical to each other specified in the plurality of layers, a defect remaining in the manufactured object.
A three-dimensional powder bed fusion additive manufacturing (PBF-AM) apparatus comprising: a build plate (22) on which a powder bed, a powder material being spread over the powder bed, is formed, a powder feeding system (16) configured to spread the powder material over the powder bed, a beam irradiation part (2) configured to irradiate the powder material spread over the powder bed with a manufacturing beam, an electron optical system configured to perform scanning with the manufacturing beam in accordance with a melting condition under which the powder material is fused and fuse the powder material spread over the powder bed, a defect candidate specifying unit (72) configured to detect, from layer data obtained for a corresponding layer in which a manufactured object is manufactured by PBF-AM, a defective portion where a sintering defect occurs as a defect candidate for the corresponding layer and specify a plurality of the defect candidates at positions substantially identical to each other in a plurality of the layers adjacent in a layering direction; and a defect detection unit (73) configured to detect, on the basis of a size in the layering direction and a size in the layer of the plurality of defect candidates at the positions substantially identical to each other specified in the plurality of layers, a defect remaining in the manufactured object.

Description

BACKGROUND Technical Field The present invention relates to an information processing apparatus, a defect detection method, and a three-dimensional powder bed fusion additive manufacturing (PBF-AM) apparatus. Related Art In recent years, three-dimensional powder bed fusion additive manufacturing (PBF-AM) techniques, which manufacture objects by overlapping thin layers of metal powder material layer by layer, have been attracting attention, and many types of PBF-AM techniques have been developed depending on differences in the powder materials and the manufacturing methods. The manufacturing method of the conventional three-dimensional powder bed fusion additive manufacturing (PBF-AM) apparatus is, for example, to spread the powder material layer by layer over a base plate installed on an upper surface of a stage. Next, with respect to the powder material spread on the base plate, only a two-dimensional structure portion corresponding to one cross section of a manufactured object is fused by a heating mechanism including an electron beam or a laser. Then, such layers of the powder material are stacked layer by layer in a height direction (Z direction) to form the manufactured object. At the time of manufacturing each layer of the manufactured object, a powder bed is formed on the base plate, and thus this manufacturing method is also referred to as a powder bed method. In the formation of the manufactured object, the powder material cannot be completely fused at a portion where sintering defect occurs, and unevenness occurs on a surface of the manufactured object in the middle of manufacturing. Since such unevenness may be a defect, in the three-dimensional PBF-AM apparatus, defect detection is performed on the basis of data acquired from a manufactured-object surface by performing camera photographing or back scattered electron (BSE) photographing. The camera photographing is, for example, a method of photographing the manufactured-object surface with visible light. The BSE photographing is a method of photographing the manufactured-object surface by detecting backscattered electrons of an electron beam emitted to the manufactured-object surface. Layer data obtained by the camera photographing or the BSE photographing is displayed on a monitor as an XY cross-sectional view per layer of the manufactured object in the middle of manufacturing. A user can confirm the state of the XY cross section immediately after fusion of the powder material using the layer data. In addition, the user has been able to specify a portion (referred to as defect candidate) that may become a defect based on the unevenness of the manufactured-object surface in the middle of manufacturing. Examples of the defect candidate include an unevenness portion generated in the layer, and a portion insufficiently fused and formed with a space. As a technique related to such defect detection, a technique described in Patent Literature 1 is known. Patent Literature 1 discloses that "the determination unit calculates, from the state of the protrusion measured by the surface state measurement unit, the height of the protrusion, and at least one of the total area of the region where the protrusion is generated and the occupation ratio of the protrusion in the sintered region, and compares the calculated values with the respective thresholds to determine whether the fabrication shape of the sintered layer is good or poor". Citation List Patent Literature Patent Literature 1: JP 2020-200501 A SUMMARY In the powder bed method, a process of further spreading the powder material on the surface where the manufactured object is fused in the middle of manufacturing and repeating the fusion of the powder material again is performed until the manufacturing of the manufactured object is completed. For this reason, even in a portion of unevenness detected as a defect candidate, when thermal energy for two layers or three or more layers is received in the fusion process performed on the next layer and further the next layer, the portion of unevenness may be re-fused and the unevenness may disappear. It can be determined that the defect is eliminated at the portion where the unevenness has disappeared by re-fusion. Therefore, in the conventional method, the defect candidate can be specified on the basis of the unevenness of the manufactured-object surface in the middle of manufacturing. However, in the conventional method, it is not possible to guarantee whether the defect candidate specified in the middle of manufacturing remains in the manufactured object after the manufacturing is completed, and the accuracy of defect detection is not high. The present invention has been made in view of such a situation, and an object thereof is to enable confirmation as to whether or not the defect candidate remains as the defect in the manufactured object on the basis of layer data obtained from a plurality of layers. An information processing apparatus according to the pr