WO2022259728A1

WO2022259728A1 - Manufacturing condition determination method, program, manufacturing condition determination apparatus, metal structure manufacturing method, and additive manufacturing apparatus

Info

Publication number: WO2022259728A1
Application number: PCT/JP2022/015883
Authority: WO
Inventors: 慎二松下; 啓嗣川中
Original assignee: 株式会社日立製作所
Priority date: 2021-06-10
Filing date: 2022-03-30
Publication date: 2022-12-15
Also published as: JP2022188819A

Abstract

Provided is a manufacturing condition determination method capable of suppressing an overheating phenomenon. In order to solve the problem, the manufacturing condition determination method comprises: a design information determining step (S1) for determining design information of a pre-designed metal structure for additive manufacturing, the design information comprising at least one of a cross-sectional area in a direction perpendicular to a manufacturing direction during additive manufacturing and a rate of change in the cross-sectional area in the manufacturing direction; an index temperature predicting step (S2) for predicting, on the basis of a manufacturing condition comprising at least one of the shape of the metal structure, constituent material thereof, and an additive manufacturing apparatus operating condition, a prediction index temperature which is a temperature at which overheating of the metal structure is caused during additive manufacturing; a target condition determining step (S3) for determining a target condition, for at least one of the cross-sectional area and the rate of change, for suppressing overheating of the metal structure during additive manufacturing; and a design information correcting step (S4) for correcting the design information so that the target condition determined in the target condition determining step (S3) can be obtained.

Description

Manufacturing condition determination method, program, manufacturing condition determination device, metal structure manufacturing method, and layered manufacturing device

The present disclosure relates to a modeling condition determination method, a program, a modeling condition determination device, a method for manufacturing a metal structure, and an additive manufacturing device.

In additive manufacturing using metal materials, various methods such as the powder bed fusion method and the directional energy deposition method are adopted, and the method of molding by melting and bonding metal materials with heat is common. Laminate manufacturing is a technique of forming a shape by stacking layers with a thickness of about several tens to several hundred μm. At this time, for example, in the powder bed fusion bonding method, powder layers are spread one by one in the area including the cross section of the modeled shape, and the powder at the locations corresponding to the modeled shape is melted and bonded by a laser or the like. Further, for example, in the directional energy deposition method, the powder supplied to a portion corresponding to the shape to be formed is melted and combined with a laser or the like.

As a technology related to layered manufacturing, claim 1 of Patent Document 1 states, "A strength prediction method for a structure manufactured by a layered manufacturing method, comprising at least one of a material scanning direction, a scanning pitch, a layering direction, and a layering pitch. A strength prediction method for a structure, which obtains a material lamination method including and estimates the strength of the structure in consideration of strength anisotropy due to the material lamination method." is described.

JP 2017-177462 A

During additive manufacturing, metal powder is melted and solidified by a laser, so heat builds up in the metal structure as the build progresses. Unintended local protrusions can occur during solidification of an excessively large weld pool, where overheating occurs due to heat build-up and excessive laser. Localized protrusions can cause stalling of the additive manufacturing apparatus even during the build. However, the technology described in Patent Document 1 does not consider such an overheating phenomenon.
The problem to be solved by the present disclosure is to provide a molding condition determination method, a program, a molding condition determination device, a method for manufacturing a metal structure, and a laminate molding apparatus capable of suppressing overheating.

The manufacturing condition determination method of the present disclosure is based on at least one molding condition of the shape of the metal structure to be laminated, the constituent material, or the operating conditions of the laminate manufacturing apparatus. and at least one of a cross-sectional area or a rate of change with respect to the manufacturing direction during the additive manufacturing, which is the overheating of the metal structure during the additive manufacturing. and a target condition determination step of determining a target condition to suppress. Other solutions will be described later in the detailed description.

According to the present disclosure, it is possible to provide a molding condition determination method, a program, a molding condition determination device, a metal structure manufacturing method, and an additive manufacturing device that can suppress overheating.

4 is a flow chart showing a modeling condition determination method and a metal structure manufacturing method of the present disclosure; It is a figure which shows the metal structure at the time of additive manufacturing. 1 is an exploded perspective view of a metal structure of the present disclosure; FIG. 1 is a side view of a metal structure of the present disclosure; FIG. 1 is a front view of a metal structure of the present disclosure; FIG. It is a front view of the metal structure which concerns on another embodiment. It is a front view of the metal structure which concerns on another embodiment. 5 is a graph showing temperature changes at each position in the height direction during laminate manufacturing of Examples 1 to 3 and Comparative Example 1. FIG. It is a figure explaining the correction method of the design information in another embodiment. 1 is a block diagram showing a modeling condition determination device and a layered modeling device of the present disclosure; FIG. It is an example of an input screen for inputting information to the input unit.

Hereinafter, a form (referred to as an embodiment) for carrying out the present disclosure will be described with reference to the drawings. In the following description of one embodiment, other embodiments applicable to the one embodiment will also be described as appropriate. The present disclosure is not limited to one embodiment below, and different embodiments can be combined or arbitrarily modified within a range that does not significantly impair the effects of the present disclosure. Also, the same members are denoted by the same reference numerals, and overlapping descriptions are omitted. Furthermore, those having the same function shall have the same name. The contents of the drawings are only schematic, and for the convenience of the drawings, the actual configuration may be changed within a range that does not significantly impair the effects of the present disclosure, or the illustration of some members may be omitted or modified between drawings. sometimes

FIG. 1 is a flow chart showing the molding condition determination method and the metal structure manufacturing method of the present disclosure. The molding condition determination method includes a design information determination step S1, an index temperature prediction step S2, a target condition determination step S3, and a design information correction step S4. The method for manufacturing the metal structure 1 (FIG. 2) includes a design information determination step S1, an index temperature prediction step S2, a target condition determination step S3, a design information correction step S4, a laminate manufacturing step S5, and support member removal. including step S6.

In the design information determination step S1, the rate of change δS of the cross-sectional area S in the direction perpendicular to the molding direction or the cross-sectional area S in the molding direction of the pre-designed metal structure 1 to be the target of lamination molding. /δz is a step of determining design information for at least one of The metal structure 1 and the forming direction will be described with reference to FIG.

FIG. 2 is a diagram showing the metal structure 1 during additive manufacturing. The structure of the moldable metal structure 1 is not limited to the illustrated example. The metal structure 1 can be manufactured by any additive manufacturing technique such as, for example, a powder bed fusion method, a directed energy deposition method, etc., but the powder bed fusion method is exemplified in the present disclosure. In the powder bed fusion bonding method, metal powder is deposited on the base plate 13 as described above. Then, the metal structure 1 having a desired structure is manufactured by repeating melting and solidification of the metal powder from the side closer to the base plate 13 to the side farther from the base plate 13 . Therefore, the upward direction on the paper surface indicated by the white arrow in FIG. 2 corresponds to the modeling direction during layered modeling.

Returning to FIG. 1, the design information of the metal structure 1 designed in advance is defined, for example, by defining the forming posture (shape) of the metal structure 1 to be formed in the forming condition determination device 100 (FIG. 8). can decide.

The index temperature prediction step S2 is based on at least one molding condition of the shape of the metal structure 1, the constituent materials, or the operating conditions of the modeling apparatus main body 30 (FIG. 8) that performs the layered manufacturing. Predicting the predictive indicator temperature, which is the temperature that will cause overheating in 1. The predicted index temperature can be predicted by the index temperature prediction step S2, and a target superheating temperature (described later) that can suppress cracking occurring at a temperature higher than the predicted index temperature can be determined. The term "overheating" as used herein refers to a state of being heated to a temperature exceeding the predicted index temperature by, for example, excessive laser light.

Among the modeling conditions, for example, the constituent materials of the metal structure 1 are, for example, the type and composition of the metal. The operating conditions of the modeling apparatus main body 30 are, for example, the output of a heat source (an irradiation device such as a laser) provided in the modeling apparatus main body 30, the laser moving speed, the preheating temperature, and the like.

In the index temperature prediction step S2, for example, the predicted index temperature is predicted by heat transfer analysis based on the modeling conditions. By heat transfer analysis, the predicted index temperature can be predicted for each of the fine regions (mesh) on the surface and inside of the metal structure 1 . As a result, the predicted index temperature can be determined for the entire metal structure 1, and the portion where overheating will occur can be predicted.

The modeling condition is either a value input by the user or a value recorded in a database (corresponding to the modeling condition DB 27 (FIG. 8)) recorded in advance corresponding to the constituent material of the metal structure 1 . Using these values, a heat transfer analysis based on build conditions can be performed.

The target condition determination step S3 determines at least one of the cross-sectional area S in the direction perpendicular to the manufacturing direction during additive manufacturing or the rate of change δS/δz of the cross-sectional area S in the manufacturing direction, and determines the metal structure during additive manufacturing. 1 is the step of determining the target condition to suppress overheating to 1. The target condition determining step S3 can determine the target condition, which is at least one of the cross-sectional area S and the rate of change δS/δz that can suppress overheating of the metal structure during lamination manufacturing. The term "suppressing overheating" as used herein is not limited to the limited meaning of not causing overheating at all, but rather mitigates the overheating phenomenon to the extent that a molten pool of a size that does not cause local protrusions during solidification is generated. It means. Specifically, for example, it means that overheating below a target superheating temperature described below is permitted.

Although the details will be described later, by controlling the cross-sectional area S or the rate of change δS/δz, the heat given during the layered manufacturing is transferred to the base plate 13 (FIG. 2) through the formed portion of the metal structure 1 as a heat transfer path. can escape to As a result, overheating of the metal structure 1 can be suppressed, and generation of an excessively large molten pool due to overheating can be suppressed. Therefore, it is possible to suppress the occurrence of unintended local protrusions during solidification.

In the target condition determination step S3, the target conditions are determined based on the target overheating temperature, which is the temperature at which the metal structure 1 is overheated and cracks occur in the metal structure 1 during additive manufacturing. In the structure having the design information determined in the design information determination step S1, overheating occurs in at least a portion of the metal structure 1, and unintended local projections may occur during solidification. Cracks (cracks, cracks, etc.) may occur in the metal structure 1 due to the occurrence of protrusions. Therefore, the above design information is corrected so that the metal structure 1 as a whole can be heated at the target superheating temperature or lower. As a result, it is possible to suppress the occurrence of local protrusions and the occurrence of cracks during solidification.

The target overheating temperature is either a value input by the user or a value recorded in a database (corresponding to the target overheating temperature DB 28 (FIG. 8)) recorded in advance corresponding to the constituent material of the metal structure 1. be. Using these values, a target superheat temperature can be determined. The target superheating temperature can be determined, for example, by experimentation, and for example, the user may input a value obtained by experimentation, or record an experimental value obtained by experimentation in a database.

Explain how to determine the target conditions based on the target superheat temperature. T is the temperature at the uppermost surface (the part with the highest temperature) of the metal structure 1, t is the time, Z is the height with respect to the modeling direction (modeling height. Height from the base plate 13 (FIG. 2)), and thermal diffusion Let α be the ratio and S be the cross-sectional area in the direction perpendicular to the forming direction.

Therefore, from the viewpoint of material properties, the overheating phenomenon is related to the thermal diffusivity α. depends on δS/δz. Of these, the thermal diffusivity α is determined by the constituent material of the metal structure 1 . Therefore, the overheating phenomenon can be suppressed (alleviated) by shaping the metal structure 1 as follows. For example, when the rate of change δS/δz≦0, at least one of the conditions of reducing the rate of change δS/δz (changing gently) or reducing the cross-sectional area S may be satisfied. On the other hand, if the rate of change .delta.S/.delta.z>0, at least one of the conditions of reducing the rate of change .delta.S/.delta.z and increasing the cross-sectional area S should be satisfied.

Also, the condition for minimizing the volume of the metal structure 1 and minimizing the overheating temperature is expressed by the following formula (2) when the minimum value is obtained based on Lagrange's method of undetermined multipliers. where k is a constant.

　α is determined by the constituent materials as described above, and k is a constant. Therefore, as shown in equation (2), if the shape of the metal structure 10 is such that the cross-sectional area S is inversely proportional to the height Z as the target condition, the overheating phenomenon can be alleviated particularly efficiently.

In the target condition determination step S3, the target condition is determined based on the target superheat temperature and the predetermined relationship that associates the target superheat temperature and the target condition (at least one of the cross-sectional area S and the rate of change δS/δz). Thereby, the target condition can be determined based on the target superheat temperature. For example, the target overheating temperature is determined from the constituent materials of the metal structure 1 based on the database (corresponding to the target overheating temperature DB 28 (FIG. 8)). Then, the target condition can be determined based on the determined target superheating temperature and the predetermined relationship.

The predetermined relationship is a formula, table, graph, etc., and there is no limit to the specific format. For example, if the predetermined relationship is a formula, then formula (1) or formula (2) can be used. Also, if the predetermined relationship is a table, a table that associates the target superheating temperature with the target condition can be used.

The predetermined relationship is, for example, a relationship in which the cross-sectional area S decreases as the height Z in the modeling direction increases. Specifically, this relationship corresponds to a structure in which the cross-sectional area S is inversely proportional to the height Z, for example. Further, the predetermined relationship is such that the cross-sectional area S becomes smaller as the height Z in the forming direction increases up to a predetermined height in the forming direction, but the cross-sectional area S is the same regardless of the forming direction above the predetermined height. Specifically, this relationship corresponds to, for example, a trapezoid whose width increases in the molding direction up to a predetermined height and whose width is the same beyond that.

FIG. 3A is an exploded perspective view of the

metal structures

1, 10 of the present disclosure. The

metal structures

1, 10 of the present disclosure are formed by additive manufacturing. Although the details will be described later, the metal structure 1 is a preliminarily designed object to be shaped, but by correcting the design information, the metal structure 10 is layered and manufactured during the layered manufacturing. After lamination manufacturing, the metal structure 1 can be manufactured by removing the support 2 that constitutes the metal structure 10 .

In the example of the metal structure 1 shown in FIG. 3A, the cross-sectional area S in the direction (laser irradiation direction, direction in the xy plane) perpendicular to the modeling direction (+z direction) is It gradually increases and is constant above a predetermined position. Also, the rate of change δS/δz is positive up to a predetermined position in the modeling direction, but is 0 above the predetermined position.

The metal structure 1 has a portion 1a that narrows in the opposite direction (downward) to the modeling direction (+z direction). For example, as a result of heat transfer analysis, it is assumed that heat is likely to accumulate in the edge portion of the portion 1a, and overheating is likely to occur. In this case, in the portion 1a, the rate of change δS/δz in the height direction of the cross-sectional area S in the modeling direction is positive. Therefore, by increasing the cross-sectional area S of at least the portion 1a, heat can be released and overheating can be suppressed.

Therefore, when forming the metal structure 1 as the final product, the metal structure 10 is provided with the support member 2 that increases the cross-sectional area S in the direction (xy direction) perpendicular to the forming direction (z direction). is additively manufactured. In the illustrated example, the support member 2 has a rectangular plate shape when viewed from the front (FIG. 3C). After the metal structure 10 is layered and manufactured, the metal structure 1 can be formed by removing the support member 2 from the formed metal structure 10 . Removal can be performed using any tool, for example.

FIG. 3B is a side view of the

metal structures

1, 10 of the present disclosure. The angle θ1 will be described later. The x-direction length of the metal structure 1 is, for example, 22 mm. The height of the metal structure 1 and the support member 2 in the forming direction is, for example, 100 mm, and the height of the portion 1a from the lower end of the metal structure 1 is, for example, 30 mm. A portion having a height of 30 mm from the lower end of the metal structure 1 corresponds to the "predetermined height" described in the above "predetermined relationship". Moreover, the thickness of the support member 2 is, for example, 1 mm.

FIG. 3C is a front view of the

metal structures

1, 10 of the present disclosure. The length (width) of the support member 2 in the y direction is, for example, 10 mm.

FIG. 4 is a front view of metal structures 1 and 11 according to another embodiment. In the example shown in FIG. 4, the support member 3 is provided so as to increase the cross-sectional area S at least at the portion 1a and to reduce the rate of change .delta.S/.delta.z. The width in the y direction at the lower end of the support member 3 is 10 mm. Although illustration is omitted, the support member 3 has the same plate shape as the support member 2 (FIG. 3B). However, the support member 3 has a right-angled triangular shape narrowing in the modeling direction (+z direction). By having such a tapered shape, the usage amount of the metal material constituting the support member 3 and the molding time can be reduced as compared with FIGS. 3A to 3C.

The angle θ2 that indicates how the support member 3 narrows is larger than the angle θ1 (FIG. 3B) of the portion 1a, so that the rate of change δS/δz can be made small (that is, the change is gentle). In addition, the support member 3 has a shape in which the cross-sectional area S becomes smaller as it is higher in the modeling direction.

FIG. 5 is a front view of

metal structures

1 and 12 according to another embodiment. In the example shown in FIG. 4, the support member 4 is provided so as to increase the cross-sectional area S at the portion 1a and decrease the rate of change .delta.S/.delta.z. Although illustration is omitted, the support member 4 has the same plate shape as the support member 2 (FIG. 3B). Moreover, the support member 4 has a shape that narrows in the molding direction, similarly to the support member 3 (FIG. 4). However, unlike the support member 3, the support member 4 has a substantially right-angled triangular shape with a parabolic shape on the oblique side. Thereby, the metal structure 10 has a shape in which the cross-sectional area S in the molding direction is inversely proportional to the height Z. As shown in FIG.

FIG. 6 is a graph showing temperature changes at each position in the height direction during laminate manufacturing in Examples 1 to 3 and Comparative Example 1. Example 1 has the structure shown in FIGS. 3A to 3C, Example 2 has the structure shown in FIG. 4, Example 3 has the structure shown in FIG. There is only thing 1. The horizontal axis is the height position from the lower end of the metal structure 1 (base plate 13 (FIG. 2)).

In Example 1, compared to Comparative Example 1, the temperature could be lowered overall, and in particular, initial overheating (30 mm or less) corresponding to the portion 1a (FIG. 3A) where overheating easily occurs could be suppressed. On the other hand, in Examples 2 and 3 in which the cross-sectional area S decreases in the height direction, the effect of suppressing overheating was exhibited even after the middle stage of modeling (shift to 30 mm in height). In particular, in Example 3, the temperature rise was suppressed to 80° C. even when forming 100 mm. Therefore, the temperature rise width of Example 3 (value obtained by subtracting the initial temperature of 25°C from 80°C) can be reduced to less than half of the temperature rise width of Comparative Example 1 (value obtained by subtracting the initial temperature of 25°C from 140°C). , it has been confirmed that a large heat dissipation promotion, that is, an overheating suppression effect is exhibited.

For example, assume that the predicted index temperature (highest part) of the metal structure 1 was 130°C as a result of the heat transfer analysis. In this case, as shown in FIG. 6, the temperature T exceeds 130.degree. Therefore, the target superheating temperature is determined to be, for example, 130° C., and support members 2 to 4 are provided to the metal structure 1 to determine the target conditions under which the temperature during lamination molding can be set to the target superheating temperature or less (130° C. or less). As a result, in Examples 1 to 3, the predicted index temperature (temperature T) can be lowered to 130° C. or less in the entire range of 0 mm to 100 mm, and the occurrence of local protrusions, cracks, etc. caused by overheating can be suppressed.

Returning to FIG. 1, the design information correction step S4 is a step of correcting the design information of the pre-designed metal structure 1 so as to achieve the target conditions determined in the target condition determination step S3. The design information correction step S4 can suppress the occurrence of protrusions, cracks, and the like due to overheating, even if the occurrence of protrusions and cracks due to overheating is expected by simply laminating and manufacturing.

In the design information correction step S4, the design information (at least one of the cross-sectional area S and the rate of change δS/δz) of the pre-designed metal structure 1 is modified so as to meet the target conditions determined in the target condition determination step S3. At least one of the area S or the rate of change δS/δz is given. As a result, the design information of the metal structure 1 designed in advance is corrected, and layered manufacturing can be performed while suppressing overheating.

Specifically, for example, as described with reference to FIGS. It is done to shape as.

The provision is such that the support members 2 to 4 having at least one of the cross-sectional area S or the rate of change δS/δz for setting the metal structure 10 to the above target conditions are integrally formed with the metal structure 1 designed in advance. This is done by correcting the design information to As a result, the metal structure 10 including the metal structure 1 can be shaped while overheating is suppressed, and the metal structure 1 can be finally manufactured. Specifically, for example, as shown in FIG. 5, the support member 4 that compensates for the shortage of the cross-sectional area S of the metal structure 1 so that the cross-sectional area S of the metal structure 10 is inversely proportional to the height Z. should be given.

FIG. 7 is a diagram explaining a method of correcting design information in another embodiment. In the examples shown in FIGS. 2A to 5, the metal structure 1 and the support members 2 to 4 are integrally formed. However, in the example shown in FIG. 7, the metal structure 1 and the support members 2 to 4 are formed separately. That is, the above-described application is performed by applying the support member 5 that is shaped in a heat-conducting and non-contact manner to the predesigned metal structure 1 . The support member 5 has at least one of the cross-sectional area S and the rate of change δS/δz for bringing the metal structure 10 to the above target conditions. By such application, the metal structure 1 can be formed directly, and unlike the support members 2 to 4, the support member removing step S6 (FIG. 1) can be omitted.

In the example shown in FIG. 7, the design information correction step S4 (FIG. 1) can be executed as follows. First, the shape of the support member 5 (the cross-sectional area S or rate of change δS/δz for achieving the target condition) is determined in the same manner as the support members 2 to 4 (FIGS. 3A to 5). Next, the design information of the metal structure 1 is corrected so that the support member 5 is simultaneously shaped in proximity to the metal structure 1 to be shaped. The term "at the same time" as used herein means that the first layer of the support member 5 is modeled after the first layer of the metal structure 1 is modeled, and then these models are repeated. Moreover, the proximity here is not limited as long as it is a non-contact distance to the metal structure 1 and heat transfer is possible. For example, the support member 5 can be formed away from the metal structure 1 at a distance at which, for example, 1 to 10, preferably 5 or less, metal particles 14, which are constituent materials of the metal structure 1, can be arranged. From the viewpoint of promoting heat transfer, it is preferable to shape the metal structure 1 and the support member 5 in a state in which metal particles 14 are present between the metal structure 1 and the support member 5 . Thereby, heat can be dissipated through the particles 14 .

The layered manufacturing of the example shown in FIG. 7 can adopt any method such as a powder bed fusion method, a directional energy deposition method, etc., but from the viewpoint of ease of stacking, the powder bed fusion method is preferable. .

Returning to FIG. 1, the layered manufacturing step S5 is a step of layeredly manufacturing the metal structure 1 so as to achieve the target information determined in the target condition determination step S3. In the illustrated example, layered manufacturing is performed based on the design information corrected in the design information correction step S4. By the layered manufacturing step S5, the metal structure 1 can be layeredly manufactured.

The specific configuration of the additive manufacturing device that performs additive manufacturing is not particularly limited, and any device that can control the operating conditions of additive manufacturing (output of heat source (irradiation device such as laser), laser moving speed, preheating temperature, etc.) can be used. Laminate manufacturing can be performed, for example, by a modeling apparatus main body 30 that performs lamination manufacturing.

The support member removing step S6 is performed after the layered manufacturing step S5, and is a step of removing the support members 2 to 4 from the metal structure 10 integrally formed with the metal structure 1. The support member removing step S6 can be omitted when the support member 5 (FIG. 7) is used. The metal structure 1 can be manufactured by the support member removing step S6.

FIG. 8 is a block diagram showing the modeling condition determining device 100 and the layered modeling device 200 of the present disclosure. The modeling condition determination device 100 includes an input unit 21, a design information determination unit 22, an index temperature prediction unit 23, a target condition determination unit 24, a design information correction unit 25, an output unit 26, a modeling condition DB 27, and a target overheating temperature DB 28 . DB is an abbreviation for database.

The modeling condition determining apparatus 100 includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), etc., although none of them are shown. The modeling condition determination apparatus 100 is embodied by developing a predetermined program (control program) stored in the ROM into the RAM and executing it by the CPU. The program referred to here is for causing a computer to execute the above method of determining molding conditions.

The layered modeling apparatus 200 includes an input device 31, a display device 32, a modeling condition determining device 100, and a modeling apparatus main body 30 that executes layered modeling. The modeling condition determination device 100 determines the modeling conditions of the metal structure 1 ( FIG. 2A ) in the modeling device main body 30 based on the input conditions from the input device 31 .

The input unit 21 receives information necessary for generating the conditions for lamination molding, which is input through the input device 31 (for example, keyboard, mouse, etc.). The necessary conditions include, for example, the shape of the metal structure, the constituent materials, the operating conditions of the layered manufacturing apparatus, the shapes of the support members 2 to 5, and the like.

FIG. 9 is an example of an input screen 211 for inputting information to the input unit 21. FIG. The input screen 211 has fields 220 for designating the shape and orientation of the metal structure 1 . In column 220, existing shapes can be referred to as initial shapes of support members 2-5, or the posture of metal structure 1 can be generated from a specified posture. The input screen 211 also has a column 221 for selecting the modeling apparatus main body 30 and constituent materials. For the modeling apparatus main body 30 and constituent materials, an existing modeling apparatus main body 30 and constituent materials may be selected, or in the case of a new modeling apparatus main body 30 and constituent materials, necessary information is entered by pressing the add button 222. can be entered and used.

The input screen 211 has a target superheat temperature button 223 that opens a setting screen window for setting the target superheat temperature. The input screen 211 includes a predicted temperature index calculation button 224 that activates the temperature index prediction unit 23 (FIG. 8). The input screen 211 has a molding condition correction button 225 for activating the design information correction section 25 (FIG. 8). The input screen 211 has a field 226 for designating a file storage location when outputting the analysis results and the optimum results to the outside in addition to checking the analysis results and the optimum results on the display screen window.

Returning to FIG. 8, the design information determination unit 22 determines design information for at least one of the cross-sectional area S and the rate of change δS/δz of the pre-designed metal structure 1 (FIG. 3A) to be laminated and manufactured. It is something to do. The design information determination unit 22 executes the design information determination step S1 (FIG. 1).

The index temperature prediction unit 23 is a temperature that causes overheating of the metal structure 1 during laminate manufacturing based on at least one molding condition of the shape of the metal structure 1, the constituent materials, or the operating conditions of the molding apparatus main body 30. It predicts the predictive index temperature. Prediction is performed based on at least one of the conditions input by the input device 31 and the modeling condition DB 27, for example. The index temperature prediction unit 23 executes the index temperature prediction step S2 (FIG. 1).

The target condition determination unit 24 determines a target condition, which is at least one of the cross-sectional area S and the rate of change δS/δz, for suppressing overheating of the metal structure 1 during additive manufacturing. The determination is made, for example, based on at least one of the conditions input by the input device 31 and the target overheating temperature DB 28 . The target condition determination unit 24 executes target condition determination step S3 (FIG. 1).

The design information correction unit 25 corrects the design information of the metal structure 1 so that the target conditions determined by the target condition determination unit 24 are achieved. The modification is performed by applying support members 2 to 5 to the metal structure 1, for example. The design information correction unit 25 executes the design information correction step S4 (FIG. 1).

The output unit 26 outputs the corrected design information to the modeling apparatus main body 30 and the display device 32 (such as a display) (only one of them may be used). The modeling apparatus main body 30 models the

metal structures

1 and 10 based on the input design information as described above.

According to the above modeling condition determining method, program, modeling condition determining apparatus 100, method for manufacturing the metal structure 1, and layered manufacturing apparatus 200, overheating can be suppressed during layered manufacturing of the metal structure 1. As a result, it is possible to suppress the occurrence of local projections during solidification due to overheating, and to suppress unintended stoppage of the laminate manufacturing apparatus. Therefore, the layered manufacturing apparatus can be used continuously, and the manufacturing efficiency can be improved. In addition, by suppressing the overheating phenomenon, it is possible to suppress the occurrence of cracks due to overheating. Thereby, the metal structure 1 having excellent reliability such as durability can be manufactured.

In particular, when a metal material with low thermal conductivity such as austenitic stainless steel or nickel-based alloy is used as the constituent material of the metal structure 1, the overheating phenomenon is likely to occur. Therefore, by using, for example, the modeling condition determination method of the present disclosure, the overheating phenomenon can be suppressed.

1 metal structure 10 metal structure 100 molding condition determination device 11 metal structure 12 metal structure 13 base plate 1a portion 2 support member 200 layered manufacturing device 21 input unit 211 input screen 22 design information determination unit 23 index temperature prediction unit 24 target Condition determination unit 25 Design information correction unit 26 Output unit 27 Molding condition DB
28 Target superheat temperature DB
3 support member 30 modeling apparatus main body 31 input device 32 display device 4 support member 5 support member S1 design information determination step S2 index temperature prediction step S3 target condition determination step S4 design information correction step S5 laminate manufacturing step S6 support member removal process

Claims

It is a temperature that causes overheating in the metal structure during additive manufacturing based on at least one manufacturing condition of the shape of the metal structure to be subjected to additive manufacturing, the constituent materials, or the operating conditions of the apparatus that performs the additive manufacturing. an index temperature prediction step of predicting a predicted index temperature;
A target condition for suppressing overheating of the metal structure during the additive manufacturing, which is at least one of a cross-sectional area in a direction perpendicular to the manufacturing direction during the additive manufacturing and a rate of change of the cross-sectional area in the manufacturing direction. and a target condition determination step of determining the molding condition determination method.
a design information determination step of determining design information of at least one of the cross-sectional area and the rate of change of the pre-designed metal structure;
2. The molding condition determination method according to claim 1, further comprising a design information correction step of correcting the design information so as to achieve the target conditions determined in the target condition determination step.
The modeling condition determination method according to claim 1, wherein, in the index temperature prediction step, the predicted index temperature is predicted by heat transfer analysis based on the modeling conditions.
4. The modeling according to claim 3, wherein the modeling conditions are either values input by a user or recorded values in a database recorded in advance corresponding to constituent materials of the metal structure. Condition determination method.
In the target condition determination step, the target condition is determined based on a target overheating temperature, which is a temperature at which the metal structure is overheated and cracks occur in the metal structure during additive manufacturing. The modeling condition determination method according to claim 1.
6. The target superheating temperature according to claim 5, wherein the target superheating temperature is either a value input by a user or a recorded value in a database recorded in advance corresponding to the constituent material of the metal structure. The molding condition determination method.
6. The molding condition according to claim 5, wherein, in the target condition determination step, the target condition is determined based on the target superheat temperature and a predetermined relationship that associates the target superheat temperature and the target condition. How to decide.
8. The modeling condition determination method according to claim 7, wherein the predetermined relationship is such that the higher the height in the modeling direction, the smaller the cross-sectional area.
The predetermined relationship is a relationship in which the cross-sectional area decreases as the height in the shaping direction increases up to a predetermined height in the shaping direction, but the cross-sectional area is the same regardless of the shaping direction above the predetermined height. 8. The molding condition determination method according to claim 7, characterized in that:
In the design information correction step, at least one of the cross-sectional area and the rate of change that satisfy the target conditions determined in the target condition determination step is added to the design information of the predesigned metal structure. 3. The molding condition determination method according to claim 2, wherein the design information of the metal structure designed in advance is corrected by:
By modifying the design information so that the support member having at least one of the cross-sectional area and the rate of change for achieving the target condition is integrally formed with the pre-designed metal structure. 11. The modeling condition determination method according to claim 10, wherein:
By providing a support member that has at least one of the cross-sectional area and the rate of change for achieving the target condition and that is heat-transferable and non-contact shaped to the pre-designed metal structure. 11. The modeling condition determination method according to claim 10, wherein:
to the computer,
It is a temperature that causes overheating in the metal structure during additive manufacturing based on at least one manufacturing condition of the shape of the metal structure to be subjected to additive manufacturing, the constituent materials, or the operating conditions of the apparatus that performs the additive manufacturing. an index temperature prediction step of predicting a predicted index temperature;
A target condition for suppressing overheating of the metal structure during the additive manufacturing, which is at least one of a cross-sectional area in a direction perpendicular to the manufacturing direction during the additive manufacturing and a rate of change of the cross-sectional area in the manufacturing direction. a target condition determination step of determining a program for executing a molding condition determination method.
It is a temperature that causes overheating in the metal structure during additive manufacturing based on at least one manufacturing condition of the shape of the metal structure to be subjected to additive manufacturing, the constituent materials, or the operating conditions of the apparatus that performs the additive manufacturing. a temperature index prediction unit that predicts a prediction index temperature;
A target condition for suppressing overheating of the metal structure during the additive manufacturing, which is at least one of a cross-sectional area in a direction perpendicular to the manufacturing direction during the additive manufacturing and a rate of change of the cross-sectional area in the manufacturing direction. and a target condition determination unit that determines the molding condition determination device.
It is a temperature that causes overheating in the metal structure during additive manufacturing based on at least one manufacturing condition of the shape of the metal structure to be subjected to additive manufacturing, the constituent materials, or the operating conditions of the apparatus that performs the additive manufacturing. an index temperature prediction step of predicting a predicted index temperature;
A target condition for suppressing overheating of the metal structure during the additive manufacturing, which is at least one of a cross-sectional area in a direction perpendicular to the manufacturing direction during the additive manufacturing and a rate of change of the cross-sectional area in the manufacturing direction. a target condition determination step for determining
A method of manufacturing a metal structure, comprising: a layered manufacturing step of layering and manufacturing the metal structure so as to achieve the target information determined in the target condition determining step.
a design information determination step of determining design information of at least one of the cross-sectional area and the rate of change of the pre-designed metal structure;
The predesigned support member having at least one of the cross-sectional area and the rate of change for bringing the metal structure to the target condition so as to meet the target condition determined in the target condition determination step. a design information correction step of correcting the design information so as to integrally form with the metal structure;
16. The method of manufacturing a metal structure according to claim 15, further comprising a support member removing step, which is performed after the layered manufacturing step and removes the support member from the layeredly manufactured metal structure.
a molding device main body that performs additive manufacturing;
a molding condition determining device that determines molding conditions for the metal structure in the molding apparatus main body, wherein the molding condition determining device is:
It is a temperature that causes overheating in the metal structure during additive manufacturing based on at least one manufacturing condition of the shape of the metal structure to be subjected to additive manufacturing, the constituent materials, or the operating conditions of the apparatus that performs the additive manufacturing. a temperature index prediction unit that predicts a prediction index temperature;
A target condition for suppressing overheating of the metal structure during the additive manufacturing, which is at least one of a cross-sectional area in a direction perpendicular to the manufacturing direction during the additive manufacturing and a rate of change of the cross-sectional area in the manufacturing direction. and a target condition determination unit that determines the layered manufacturing apparatus.