JP7655050B2 - METHOD FOR DESIGNING ADDITIVE PRODUCTS, APPARATUS FOR DESIGNING ADDITIVE PRODUCTS, AND METHOD FOR MANUFACTURING ADDITIVE PRODUCTS - Google Patents

Description

The present invention relates to a method for designing an additive product, an apparatus for designing an additive product, and a method for manufacturing an additive product.

Additive manufacturing is known to include, for example, powder bed fusion and directed energy deposition. Powder bed fusion performs additive manufacturing by irradiating a light beam (laser beam, electron beam, etc.) onto a flatly spread material powder. Powder bed fusion methods include selective laser melting (SLM) and electron beam melting (EBM). Directed energy deposition performs additive manufacturing by controlling the position of a head that irradiates a light beam and ejects material powder. Directed energy deposition methods include laser metal deposition (LMD) and direct metal printing (DMP).

In powder bed fusion additive manufacturing, an additive product is created by melting and solidifying a flatly laid out powder of material, layer by layer. For this reason, of the powder bed fusion and directed energy deposition methods, powder bed fusion additive manufacturing is suitable for precisely creating additive products with internal spaces.

Patent Document 1 discloses a technology for manufacturing three-dimensional additive products using powder bed fusion additive manufacturing, in which the shape of the additive product is designed by applying topology optimization to three-dimensional data, and an additive product having an internal space is manufactured.

JP 2019-167562 A

In general, when topology optimization is applied to design the shape of an additive product, if topology optimization is performed with the entire additive product as the design domain, optimization is performed including areas other than the area where the optimization objective is set. This may result in the influence of relatively less important parts, and as a result, the optimal shape in the area where the optimization objective is set, in other words, a shape that achieves the optimization objective, may not be designed. In addition, when topology optimization is performed for a three-dimensional additive product, the amount of calculation becomes enormous, which may result in increased calculation costs and longer analysis time (calculation time).

The present invention aims to provide a method for designing an additive product, an apparatus for designing an additive product, and a method for manufacturing an additive product, which can reduce calculation costs and shorten analysis time to design an optimal shape.

(Method of designing additive manufacturing products)
One aspect of the present invention is
A method for designing an additive product that is additively manufactured to have an internal space by an additive manufacturing device that irradiates a material powder with a light beam and melts and solidifies the material powder to perform additive manufacturing, comprising:
A region setting process for setting a curved surface including the internal space of the additive product to be additively manufactured, the curved surface being a quadrangle when expanded two-dimensionally;
a conversion step of converting the curved surface set in the area setting step into development data in a quadrangle;
an optimization step of performing topology optimization based on a predetermined optimization objective on the development data converted in the conversion step;
a reconversion step of reconverting the two-dimensional data subjected to the topology optimization in the optimization step into three-dimensional data;
The present invention relates to a method for designing additive manufacturing products, which involves carrying out the steps above in sequence.

(Additive manufacturing design device)
Another aspect of the present invention is
An additive manufacturing device that performs additive manufacturing by irradiating a material powder with a light beam and melting and solidifying the material powder, and designs an additive manufacturing product that is additively manufactured to have an internal space,
A region setting unit that sets a curved surface including the internal space of the additive product to be additively manufactured, the curved surface being a quadrangle when expanded two-dimensionally;
an area development unit for converting the curved surface set by the area setting unit into development data in which the curved surface is developed into a quadrangle;
an optimization unit that performs topology optimization on the development data converted by the region expansion unit based on a predetermined optimization objective;
a reconversion unit that reconverts the two-dimensional data that has been subjected to the topology optimization by the optimization unit into three-dimensional data;
The present invention relates to an additive manufacturing design device equipped with the above.

( Method of manufacturing additive products)
Another aspect of the present invention is
A design process according to the additive manufacturing design method;
A manufacturing method for an additive product, comprising:
The additive product is a mold having a flow path for a fluid to flow through and a cavity into which a molten material is supplied;
The manufacturing process includes:
supplying the material powder;
irradiating the powdered material with the light beam;
melting the powder of material with the light beam;
solidifying the molten powder of material;
The present invention relates to a method for producing an additive product, comprising:
Another aspect of the present invention is
A design process according to the additive manufacturing design method;
A manufacturing method for an additive product, comprising:
The additive product is a main shaft of a machine tool having a flow path for flowing a fluid, and including a rotating member and a housing having a cylindrical portion through which the rotating member is inserted,
The manufacturing process includes:
supplying the material powder;
irradiating the powdered material with the light beam;
melting the powder of material with the light beam;
solidifying the molten powder of material;
The present invention relates to a method for producing an additive product, comprising:

According to these methods, a first region that is relatively important for the optimization objective is set, and the set first region is expanded into two dimensions, after which topology optimization is applied. This makes it possible to design an optimal shape in the first region, in other words, a shape that achieves the optimization objective, without being affected by the second region that is relatively less important for the optimization objective. In addition, because topology optimization is performed by expanding into two dimensions, the amount of calculations can be reduced compared to when topology optimization is performed on a three-dimensional additive product, and as a result, calculation costs can be reduced and analysis time (calculation time) can be shortened.

FIG. 1 illustrates an additive manufacturing device and an optimal shape design device. FIG. 2 is a block diagram showing the configuration of a control device of the additive manufacturing device of FIG. 1 . FIG. 2 is a diagram for explaining the configuration of an additive product that is additively manufactured so as to have an internal space by the additive manufacturing apparatus of FIG. FIG. 2 is a block diagram for explaining the configuration of the optimum shape design device of FIG. 1. 5 is a diagram for explaining a first region and a second region set by the region setting unit (region setting step) in FIG. 4 . FIG. 5 is a diagram for explaining development view data of a first region outputted by the region development unit (conversion step) of FIG. 4 . FIG. 5 is a diagram for explaining a flow path structure designed by applying topology optimization by the flow path structure design unit (optimization step) in FIG. 4 . FIG. 5 is a diagram for explaining two-dimensional coordinate data of a flow channel structure generated by the coordinate data generating unit (reconversion step) in FIG. 4 . FIG. 5 is a diagram for explaining a three-dimensional model generated by the three-dimensional model generating unit (reconversion step) in FIG. 4 . FIG. FIG. 5 is a diagram for explaining the shape finally designed by the final shape design unit (shape optimization process) of FIG. 4 . 5 is a diagram for explaining a first region, a second region, a third region, and a fourth region set by the region setting unit (region setting step) in FIG. 4 according to a first modified example. FIG. 5 is a diagram for explaining development view data of a first area, a third area, and a fourth area outputted by the area development unit (conversion step) of FIG. 4 according to a first modified example. FIG. FIG. 5 is a diagram for explaining a flow path structure designed by applying topology optimization by the flow path structure design unit (optimization step) of FIG. 4 according to a first modified example. 5 is a diagram for explaining two-dimensional coordinate data of a flow path structure generated by the coordinate data generating unit (reconversion step) in FIG. 4 according to a first modified example. FIG. FIG. 5 is a diagram for explaining the shape finally designed by the final shape design unit (shape optimization process) of FIG. 4 . 13A and 13B are diagrams for explaining a flow path structure designed by a flow path structure design unit (optimization step) according to a second modified example. 13A and 13B are diagrams illustrating two-dimensional coordinate data of a flow path structure generated by a coordinate data generating unit (reconversion step) according to a second modified example. FIG. 13 is a block diagram for explaining a configuration of an optimum shape design device according to a third modified example.

(1. Configuration of additive manufacturing device 1)
The configuration of the additive manufacturing apparatus 1 will be described with reference to the drawings. The additive manufacturing apparatus 1 of this example employs a powder bed fusion method and an SLM method. As shown in FIG. 1, the additive manufacturing apparatus 1 is an apparatus for manufacturing an additive product W having an internal piping T as an internal space by repeatedly irradiating a light beam 40a onto a metal powder S as a material powder arranged in layers (layers).

Here, the light beam 40a includes, for example, a laser beam and an electron beam, as well as various other beams capable of melting the metal powder S. In addition, various lasers such as a fiber laser, a _CO2 laser (far-infrared laser), and a semiconductor laser can be applied to the laser beam, and the type is appropriately determined depending on the target metal powder S (for example, aluminum, stainless steel, titanium, maraging steel, alloy tool steel, etc.).

As shown in FIG. 1, the additive manufacturing device 1 includes a chamber 10, an additive product support device 20, a powder supply device 30, a light beam irradiation device 40, a heating device 50, and a control device 60.

The chamber 10 is configured so that the air inside can be replaced with an inert gas such as He (helium), _N2 (nitrogen), Ar (argon), etc. Note that the chamber 10 may be configured so that the pressure inside can be reduced instead of replacing the air inside with an inert gas.

The additive product support device 20 is provided inside the chamber 10 and is composed of a support member for additively manufacturing the additive product W. The additive product support device 20 includes an additive manufacturing container 21, a lift table 22, and a base 23. The additive manufacturing container 21 has an opening on the upper side and has an inner wall surface parallel to the vertical axis. The lift table 22 is provided so as to be movable up and down along the inner wall surface inside the additive manufacturing container 21. The base 23 is detachably placed on the upper surface of the lift table 22, and the upper surface of the base 23 is a portion for additively manufacturing the additive product W. In other words, the base 23 arranges the metal powder S in a layer on its upper surface as the lift table 22 descends, and is capable of supporting the additive product W during additive manufacturing.

The powder supplying device 30 is provided inside the chamber 10 and adjacent to the additive manufacturing support device 20. The powder supplying device 30 includes a powder storage container 31, a supply table 32, and a recoater 33. The powder storage container 31 has an opening on the upper side, and the height of the opening of the powder storage container 31 is set to be the same as the height of the opening of the additive manufacturing container 21. The powder storage container 31 has an inner wall surface parallel to the vertical axis. The supply table 32 is provided inside the powder storage container 31 so as to be movable in the vertical direction along the inner wall surface. In the powder storage container 31, metal powder S is stored in the upper area of the supply table 32.

The recoater 33 is provided so as to be able to move back and forth along the upper surfaces of both the openings of the additive manufacturing container 21 and the powder storage container 31 over the entire area of both openings. For example, when the recoater 33 moves from right to left in the left-right direction of FIG. 1, that is, when it moves from the opening of the powder storage container 31 toward the opening of the additive manufacturing container 21, it transports the metal powder S protruding from the opening of the powder storage container 31 to the additive manufacturing container 21. This causes the metal powder S to be spread (arranged) evenly.

The recoater 33 then smoothes the transported metal powder S on the upper surface of the base 23, which has been lowered together with the lowered lift table 22, and arranges the same type of metal powder S in a layer on the upper surface of the base 23, i.e., recoats it. Here, "the same type" means that the material of the metal powder S, which is the material powder, is the same, and the average particle size, etc. of the metal powder S falls within a specified range.

As shown in FIG. 1, the light beam irradiation device 40 is arranged, for example, outside the chamber 10, and irradiates a light beam 40a from outside the chamber 10 onto the surface of the same type of metal powder S arranged in a layer on the upper surface of the base 23. Note that, although this example illustrates a case where the light beam irradiation device 40 is arranged outside the chamber 10, it is also possible to arrange the light beam irradiation device 40 inside the chamber 10.

The light beam irradiation device 40 irradiates the recoated metal powder S with a light beam 40a (e.g., the laser beam and electron beam described above, etc.) to heat the metal powder S to a temperature above its melting point. This causes the metal powder S to melt and then solidify (or sinter), and an additive product W consisting of an integrated layer is additively manufactured. In other words, adjacent metal powders S are integrated by fusion bonding.

The light beam irradiation device 40 includes a laser oscillator 41 and a laser head 42. The light beam irradiation device 40 also includes an optical fiber 43 that transmits the light beam 40a (e.g., near-infrared laser light) oscillated from the laser oscillator 41 to the laser head 42.

The light beam irradiation device 40 can move the irradiation position of the light beam 40a and change the beam intensity according to a preset program. By moving the irradiation position of the light beam 40a, a three-dimensional additive product W having an internal piping T as a flow path can be additively manufactured as shown in FIG. 2. Here, the light beam 40a can be irradiated to an area narrower than the area heated by the heating device 50. The light beam 40a is irradiated into the chamber 10 through transparent glass or resin provided on the upper side of the chamber 10.

The heating device 50 is built into the lift table 22. The heating device 50 is a heater for heating the additive product W via the base 23, and heats the entire base 23 via the lift table 22. The heating device 50 can be various heaters, such as a coil heater, cartridge heater, nozzle heater, or planar heater. The heating range by the heating device 50 is set to a range that includes part of the irradiation range of the light beam 40a. Here, the heating device 50 does not melt the metal powder S, unlike the light beam 40a.

(2. Configuration of control device 60)
The control device 60 is a microcomputer whose main components include a CPU, a ROM, a RAM, an interface, etc., and controls the overall operation of the additive manufacturing device 1. That is, the control device 60 controls the additive product support device 20, the powder supply device 30, the light beam irradiation device 40, and the heating device 50. For this reason, as shown in Fig. 2, the control device 60 includes a data storage unit 61, a lift table operation control unit 62, a powder supply control unit 63, a light beam irradiation control unit 64, and a heating control unit 65. In addition, the control device 60 is connected to an optimal shape design device 70 described later so as to be able to communicate with the device.

The data storage unit 61 contains data for each divided layer obtained by dividing the additive product W having internal piping T formed into a two-dimensional or three-dimensional shape at a predetermined thickness, and stores various data including shape data SD that represents the shape of the divided layer. Here, the shape data SD is supplied from an optimal shape design device 70, the details of which are omitted in FIG. 2. The optimal shape design device 70 has a so-called CAD (Computer Aided Design) function.

The lift table operation control unit 62 controls the operation of a drive device (not shown) that raises and lowers the lift table 22. When the powder supplying device 30 supplies the metal powder S, the lift table operation control unit 62 lowers the lift table 22 to a preset lowering amount.

The powder supply control unit 63 controls the operation of the powder supply device 30. Specifically, the powder supply control unit 63 controls the supply table 32 to move vertically to cause the metal powder S contained in the powder storage container 31 to be pushed out from the opening of the powder storage container 31, and controls the recoater 33 to move back and forth.

The light beam irradiation control unit 64 controls the operation of the light beam irradiation device 40. Specifically, the light beam irradiation control unit 64 controls the irradiation position (irradiation trajectory) and beam intensity of the light beam 40a irradiated by the light beam irradiation device 40 based on the shape data SD stored in the data storage unit 61.

The heating control unit 65 controls the operation of the heating device 50. Note that the details of the operation control of the heating device 50 by the heating control unit 65 are not directly related to the present invention, so a description thereof will be omitted.

(3. Examples of additive products W)
An example of the additive product W will be described with reference to FIG. 3. The additive product W is additively manufactured (modeled) by the additive manufacturing device 1 described above. Therefore, the additive product W can be any three-dimensional shape. In this example, the additive product W is exemplified by a mold used for injection molding, press processing, etc. It goes without saying that the additive product W is not limited to a mold, and can be various products, parts, etc.

The additive product W has, for example, a rectangular parallelepiped outer shape. The outer shape of the additive product W can be any shape. The additive product W has a recess H as a cavity formed in a mold into which molten material is supplied. The recess H is formed on the upper surface of FIG. 3 so as to open, for example, in a circular shape. In this example, the recess H is a cylindrical shape with a bottom, having a cylindrical inner circumferential surface (cylindrical portion) and a bottom surface (the circular surface at the bottom of FIG. 3).

The additive product W further has an internal piping T, which is a flow path, as an internal space. The internal piping T is disposed adjacent to the recess H, which is the cooling target, and is formed in a curved shape along the circumferential surface of the cylindrical portion of the recess H, and a fluid, for example, cooling water, which is a cooling medium for cooling the circumferential surface of the recess H, flows through the internal piping T. The cooling medium is not limited to a liquid, and may be a gas. The flow path structure of the internal piping T is designed by an optimal shape design device 70, which will be described later, so that, for example, the cooling effect on the circumferential surface of the recess H is good. In this example, the internal piping T is connected to an inlet I through which the cooling water flows and an outlet O through which the cooling water is discharged, and is formed in a curved shape, i.e., an arc shape, along the circumferential surface of the recess H.

In this example, the flow path structure of the internal pipe T designed as the optimal shape has a first pipe T1 and a second pipe T2 that branch the cooling water flowing in from the inlet I around the recess H and circulates it to the outlet O. Furthermore, the flow path structure of the internal pipe T is designed and formed so that the first pipe T1 branches into flow portions T11 and T12, and the second pipe T2 branches into flow portions T21 and T22.

Here, the shape of the internal pipe T around the center line is an arc shape, but it can be any shape. Also, the shape of the recess H as the cavity of the mold is changed appropriately according to the shape of the object to be molded. Therefore, the internal pipe T can also be made into an appropriate shape according to the shape of the recess H that will become the cavity.

The additive product W can also be, for example, the spindle of a machine tool. The spindle of the machine tool has a cooling flow passage formed in a cylindrical portion through which the rotating member of the spindle passes. In this case, for example, the flow passage can be formed in any shape, such as a spiral, depending on the cooling effect (cooling performance).

(4. Configuration of optimal shape design device 70)
The optimal shape design device 70 as a design device of this example designs an optimal shape of the internal pipe T for the additive product W additively manufactured by the additive manufacturing device 1 so as to realize an optimization objective related to the characteristics of the fluid flowing through the internal pipe T as a flow path, which is an internal space. Here, an example of the fluid characteristics in this example is the cooling characteristics of the cooling water as a cooling medium, which is a fluid, cooling the recess H, which is the cooling target. The optimization objective in this example is to design an optimal shape of the internal pipe T that can minimize the variation in the cooling temperature in the recess H and efficiently cool it, that is, minimize the variation in the cooling characteristics of the cooling water, which is a fluid. In particular, the optimal shape design device 70 designs an optimal flow path structure of the internal pipe T by applying topology optimization.

As shown in FIG. 4, the optimal shape design device 70 includes a region setting unit 71, a region expansion unit 72, a flow path structure design unit 73, a coordinate data generation unit 74, a three-dimensional model generation unit 75, and a final shape design unit 76. Each of the units 71, 72, 73, 74, 75, and 76 constituting the optimal shape design device 70 is configured with a processor, a storage device, etc., and is realized by the processor executing a program (not shown).

The region setting unit 71 executes the region setting process. As shown in FIG. 5, the region setting unit 71 sets a first region R1 in which the internal piping T is provided for a temporary additive product W1 of a three-dimensional shape in which the internal piping T is omitted, that is, a region in which the flow path structure is designed and has a relatively high importance for the optimization purpose, and a second region R2 in which the flow path structure is not designed and has a relatively low importance for the optimization purpose. In this example, as described above, the internal piping T formed is to efficiently cool the periphery of the recess H in the final additive product W with reduced variation as an optimization purpose in topology optimization. For this reason, the region setting unit 71 sets the periphery of the recess H shown by the thick line in FIG. 5 as the cooling target part, more specifically, the peripheral surface of the recess H with high importance for cooling, i.e., the two-dimensional surface, as the first region R1, and sets the part away from the periphery of the recess H, i.e., the part with low importance for cooling, as the second region R2.

The area expansion unit 72 executes a conversion process. The area expansion unit 72 outputs development data OZ in which the first area R1 (i.e., the two-dimensional peripheral surface of the recess H) is expanded so that the inlet I and outlet O to be finally set are located at both ends, as shown in FIG. 6, for the first area R1, which is the surface set by the area setting unit 71, i.e., the peripheral surface of the recess H. In this case, as described below, the flow path structure design unit 73 designs a flow path structure that connects the inlet I and outlet O for the development data OZ representing the expanded first area R1.

The flow path structure design unit 73 executes an optimization process. In this example, the flow path structure design unit 73 applies topology optimization to the development diagram data OZ of the first region R1 developed in two dimensions, so that the actual cooling temperature of the recess H, which can be experimentally measured in advance, is maintained with reduced variation from the set target cooling temperature. The designed first pipe T1 (flow portions T11, T12) and second pipe T2 (flow portions T21, T22) are, for example, the flow path structure Z shown in FIG. 7.

Here, the flow path structure design unit 73 applies topology optimization to the development view data OZ of the first region R1 expanded in two dimensions, i.e., the two-dimensional data. Therefore, for example, the processing time required for topology optimization can be shortened compared to performing topology optimization on the three-dimensional data before expanding the first region R1. Furthermore, the flow path structure design unit 73 applies topology optimization only to the first region R1, which is the cooling target, i.e., the peripheral surface of the recess H of the additive product W. This makes it possible to eliminate the influence of the second region R2, which is not the cooling target, in the topology optimization, and to design a flow path structure Z of the internal piping T specialized for cooling the peripheral surface of the recess H.

More specifically, the flow path structure design unit 73 applies topology optimization with the objective function of minimizing the variation in the actual cooling temperature relative to the target cooling temperature in the first region R1 (so-called cooling unevenness), and with the constraint function of zero radial expansion of the recess H of the internal pipe T. The flow path structure Z of the internal pipe T obtained by such topology optimization is a structure that can reduce the variation in the cooling temperature on the circumferential surface of the recess H. However, in topology optimization, the radial expansion of the recess H of the internal pipe T is limited. In other words, the flow path structure Z of the internal pipe T only has a two-dimensional structure expanded in the two-dimensional first region R1. For this reason, it is necessary to expand the flow path structure Z of the internal pipe T designed by topology optimization in the radial direction of the recess H to form a three-dimensional shape.

The coordinate data generating unit 74 executes a reconversion process. The coordinate data generating unit 74 generates coordinate data ZD of the shape of the flow path structure Z on two-dimensional coordinates as shown in FIG. 8 for the two-dimensional flow path structure Z designed by the flow path structure design unit 73 through topology optimization. In the coordinate data ZD shown in FIG. 8, the horizontal axis corresponds to the length of the circumferential surface of the recess H of the additive product W, and the vertical axis corresponds to the axial length of the recess H of the additive product W. The coordinate data generating unit 74 generates coordinate data ZD on two-dimensional coordinates of the axial length of the recess H relative to the length of the circumferential surface of the recess H for the flow path structure Z of the internal piping T designed by the flow path structure design unit 73 through topology optimization.

The three-dimensional model generating unit 75 executes a reconversion process. The three-dimensional model generating unit 75 performs a calculation process on the coordinate data ZD on the two-dimensional coordinates generated by the coordinate data generating unit 74 to generate a three-dimensional model, in other words, three-dimensional data, in which the inlet I and the outlet O are arranged adjacent to each other in this example. That is, by this calculation process, the horizontal axis shown in FIG. 8 is converted into a circle corresponding to the circumferential surface of the recess H of the additive product W, and the vertical axis coincides with the axial direction of the recess H, and as a result, the two-dimensional flow path structure Z designed by topology optimization is reconverted into three-dimensional data arranged along the circumferential surface of the recess H. Then, the three-dimensional model generating unit 75 expands the two-dimensional flow path structure in the radial direction of the recess H as shown in FIG. 9 based on the size of the pipe diameter preset for the internal pipe T, more specifically, the flow parts T11 and T12 of the first pipe T1 and the flow parts T21 and T22 of the second pipe T2. As a result, a three-dimensional model M in which the internal pipe T is three-dimensionalized, that is, having three-dimensional data, is generated as shown in FIG. 9.

The final shape design unit 76 executes a shape optimization process. The final shape design unit 76 takes into account, for example, additive manufacturing constraints in the additive manufacturing device 1 for the three-dimensional model M generated by the coordinate data generation unit 74 and the three-dimensional model generation unit 75 in the reconversion process, and finally designs an internal piping T that can be additively manufactured by the additive manufacturing device 1, as shown in FIG. 10. In this case, the final shape design unit 76 also finally designs the passages that respectively connect the internal piping T to the inlet I and the outlet O. Then, the final shape design unit 76 outputs shape data SD that represents the shape of the additive product W including the shape-optimized internal piping T to the control device 60.

In the control device 60, the additive manufacturing device 1 is operated based on the shape data SD output from the final shape design unit 76 of the optimal shape design device 70. This makes it possible to additively manufacture an additive product W (mold) having an optimally shaped internal piping T (internal space and flow path) as shown in FIG. 3.

As can be understood from the above explanation, according to the optimal shape design device 70 of this example, in the region setting process, the region setting unit 71 sets a first region R1 that is relatively important for the optimization purpose, and in the conversion process, the region expansion unit 72 expands the set first region R1 into two dimensions, and then in the optimization process, the flow path structure design unit 73 applies topology optimization to the expansion view data OZ of the first region R1 to design the flow path structure Z. Then, in the reconversion process, the coordinate data generation unit 74 and the three-dimensional model generation unit 75 generate a three-dimensional model M having three-dimensional data of the internal piping T based on the flow path structure Z, and in the shape optimization process, the final shape design unit 76 designs the final shape of the internal piping T and outputs the shape data SD to the control device 60 of the additive manufacturing device 1.

As a result, in topology optimization, it is possible to design the optimal shape in the first region R1, in other words, the shape of the internal piping T (internal space (flow path)) that achieves the optimization objective, without being affected by the second region R2, which is relatively less important for the optimization objective. In addition, because topology optimization is performed on the two-dimensionally expanded development data OZ, the amount of calculations can be reduced compared to when topology optimization is performed on a three-dimensional additive product W, and as a result, calculation costs can be reduced and analysis time (calculation time) can be shortened.

(5. First Alternative Example)
In the above-described example, the region setting unit 71 of the optimal shape design device 70 sets a first region R1 which is a region for designing the flow path structure Z, in other words, a region for performing temperature control. In the above-described example, the flow path structure design unit 73 applies topology optimization to design the flow path structure Z having the internal piping T in the first region R1. In the above-described example, the final shape design unit 76 designs passages that respectively connect the internal piping T to the inlet I and the outlet O.

Alternatively, the flow path structure design unit 73 can apply topology optimization related to pressure (pressure loss) to design piping that connects the designed internal piping T with each of the inlet I and outlet O. The first alternative example is described in detail below.

In the first variant, the region setting unit 71 of the optimal shape design device 70 sets the first region R1 and the second region R2 in the same manner as in the present example described above, and also sets, as shown in FIG. 11, a third region R3, which is a cross section including the shortest path in the radial direction of the recess H connecting the start end R1a of the first region R1 and the inlet I, and a fourth region R4, which is a cross section including the shortest path in the radial direction of the recess H connecting the end R1b of the first region R1 and the outlet O. In the first variant, the third region R3 and the fourth region R4 are respectively a cross section including the shortest path connecting the start end R1a and the inlet I and a cross section including the shortest path connecting the end R1b and the outlet O. However, the third region R3 and the fourth region R4 may be respectively a cross section including the start end R1a and the inlet I and a cross section including the end R1b and the outlet O.

In the first variant, the region expansion unit 72 of the optimal shape design device 70 outputs development data OZ1 as shown in FIG. 12 for the first region R1, third region R3, and fourth region R4, which are surfaces set by the region setting unit 71. Here, in the development data OZ1, the inlet I is located in the third region R3, and the outlet O is located in the fourth region R4. In the first variant, the flow path structure design unit 73 designs the flow path structure Z1 for the development data OZ1 in which the first region R1, third region R3, and fourth region R4 are expanded.

Specifically, the flow path structure design unit 73 designs the internal piping T in the first region R1 by applying topology optimization related to temperature control in the same manner as in the present example described above. In addition, the flow path structure design unit 73 applies topology optimization to the two-dimensionally expanded development data OZ of the third region R3 and the fourth region R4 to design an inflow piping T3 that connects the internal piping T to the inlet I in the third region R3, and designs an outflow piping T4 that connects the internal piping T to the outlet O in the fourth region R4, so as to reduce and maintain pressure loss.

Here, the flow path structure design unit 73 also determines the connection positions of the internal pipe T with the inlet pipe T3 and the outlet pipe T4 by applying topology optimization related to pressure (pressure loss). This makes it possible to reduce the overall pressure loss in the internal pipe T, the inlet pipe T3 and the outlet pipe T4. The designed internal pipe T, the inlet pipe T3 and the outlet pipe T4 are, for example, the flow path structure Z1 shown in FIG. 13.

Here, in the first variant, the flow path structure design unit 73 also applies topology optimization to the development diagram data OZ1 of the first region R1, the third region R3, and the fourth region R4 expanded in two dimensions, i.e., the two-dimensional data. That is, the flow path structure design unit 73 of the first variant applies topology optimization related to temperature control in the first region R1, as in the present example described above. Also, the flow path structure design unit 73 of the first variant applies topology optimization related to pressure (pressure loss) in the third region R3 and the fourth region R4. Therefore, in the first variant, the processing time required for topology optimization can be shortened, for example, compared to the case of performing topology optimization on three-dimensional data before expanding the first region R1, the third region R3, and the fourth region R4.

The flow path structure design unit 73 can simultaneously or independently perform topology optimization related to temperature control in the first region R1 and topology optimization related to pressure (pressure loss) in the third region R3 and the fourth region R4. When the flow path structure design unit 73 simultaneously performs topology optimization related to temperature control and topology optimization related to pressure (pressure loss) to design the flow path structure Z1, the pressure loss of the entire flow path structure Z1 can be reduced. On the other hand, when the flow path structure design unit 73 performs topology optimization related to temperature control and topology optimization related to pressure (pressure loss) separately (independently) to design the flow path structure Z1, precise temperature control by the internal piping T in the first region R1 can be achieved, and pressure loss in the inlet piping T3 and the outlet piping T4 can be reduced.

Here, even in the topology optimization of the first variant, the radial expansion of the recesses H of the internal pipe T, inlet pipe T3, and outlet pipe T4 is limited. In other words, the flow path structure Z1 of the internal pipe T, inlet pipe T3, and outlet pipe T4, like the flow path structure Z of the present example described above, merely has a two-dimensional structure expanded in the two-dimensional first region R1, third region R3, and fourth region R4. For this reason, the flow path structure Z1 of the internal pipe T, inlet pipe T3, and outlet pipe T4 designed by topology optimization also needs to be expanded in the radial direction of the recesses H to form a three-dimensional shape.

Therefore, the coordinate data generating unit 74 generates coordinate data ZD1 of the shape of the flow path structure Z1 on two-dimensional coordinates as shown in FIG. 14 for the two-dimensional flow path structure Z1 designed by the flow path structure design unit 73 through topology optimization. In the coordinate data ZD1 shown in FIG. 14, the horizontal axis corresponds to the circumferential and radial length of the recess H of the additive product W, and the vertical axis corresponds to the axial length of the recess H of the additive product W. The coordinate data generating unit 74 generates coordinate data ZD1 on two-dimensional coordinates of the axial length of the recess H relative to the circumferential and radial length of the recess H for the flow path structure Z1 of the internal piping T, the inflow piping T3, and the outflow piping T4 designed by the flow path structure design unit 73 through topology optimization.

In the first variant, similarly to the present example described above, the three-dimensional model generation unit 75 performs calculation processing to generate a three-dimensional model, in other words, three-dimensional data, in which the inlet I and the outlet O are arranged adjacent to each other, for the coordinate data ZD1 on the two-dimensional coordinate system generated by the coordinate data generation unit 74. Then, the final shape design unit 76 executes a shape optimization process. That is, in the first variant, the final shape design unit 76 takes into account, for example, additive manufacturing constraints in the additive manufacturing device 1 for the generated three-dimensional model, and finally designs the internal piping T, inlet piping T3, and outlet piping T4 that can be additively manufactured by the additive manufacturing device 1, as shown in FIG. 15. The rest is the same as in the present example described above.

Therefore, the first variant example also provides the same effect as the present example described above. Furthermore, by applying topology optimization, the inlet pipe T3 and the outlet pipe T4 can be designed taking into account the pressure (pressure loss).

(6. Second Alternative Example)
In the above-described present example and first modified example, the first region R1 is the peripheral surface of the recess H, and the internal pipe T has a simple circular flow path cross-sectional shape. In this case, the final shape design unit 76 designs the final shape of the internal pipe T so that the flow path cross-sectional shape is circular, according to the flow path structure Z determined by performing topology optimization.

However, for example, if the cross-sectional shape of the flow passage of the internal pipe T is complex, it is also possible to configure the first region R1 with multiple two-dimensional peripheral surfaces and perform topology optimization for each peripheral surface to determine the flow passage structure Z, as shown in Figures 16 and 17, which illustrate the case of the above-mentioned example. In this case, by synthesizing each flow passage structure (i.e., each peripheral surface), a three-dimensional model M of the internal pipe T can be generated and the final shape can be designed.

(7. Third Alternative Example)
In the above-mentioned present embodiment, the first modified embodiment, and the second modified embodiment, the three-dimensional model generating unit 75 and the final shape designing unit 76 generate and finally design the internal pipe T, i.e., the flow portions T11 and T12 of the first pipe T1 and the flow portions T21 and T22 of the second pipe T2, so as to have a preset pipe diameter. Alternatively, the three-dimensional model generating unit 75 and the final shape designing unit 76 may determine the pipe diameter (flow rate or flow rate) corresponding to the target temperature (target cooling temperature) using a database 77 that stores, for example, the relationship between the flow rate (or flow velocity) and temperature related to the pipe diameter, i.e., the characteristics of the fluid, as shown in FIG. 18. This makes it possible to design a more optimal internal pipe T and to reduce the pressure loss of the fluid (cooling water) flowing through the internal pipe T.

(8. Other)
In the above-mentioned present example, the first modified example, the second modified example, and the third modified example, a die having a bottomed cylindrical recess H which is a cavity is exemplified as the additive product W. However, the additive product W is not limited to a die, and can be, for example, the spindle of the above-mentioned machine tool as long as it has an internal space, in particular, a cooling passage as a flow passage.

The spindle of the machine tool has a rotating member and a housing having a cylindrical portion through which the rotating member is inserted. In this case, the cylindrical portion may become hot due to the rotation of the rotating member, and must be appropriately cooled. Therefore, when the spindle of the machine tool is manufactured by the additive manufacturing device 1, the cooling path for cooling the cylindrical portion can be optimally designed by going through a region setting process, a conversion process, an optimization process, a reconversion process, and, if necessary, a shape optimization process according to the design method using the optimal shape design device 70. Therefore, even when the spindle of the machine tool is additively manufactured as the additive product W, a cooling path of an optimal shape for cooling the cylindrical portion that forms the spindle can be designed according to the design method using the optimal shape design device 70, and the same effects as those of the present example, the first variant, the second variant, and the third variant described above can be obtained.

In addition, in the above-mentioned present example, the first variant, the second variant, and the third variant, an internal pipe T having a simple shape is exemplified as the internal space formed in the additive product W. However, with the additive manufacturing device 1, additive manufacturing is possible even if the internal space has a complex shape.

However, if the internal space has a complex shape, such as a box shape, the shape of the internal space formed during additive manufacturing may change due to the effects of gravity, etc. For this reason, if the shape of the internal space is complex, the final shape design unit 76 can design, for example, a support member that prevents the overhanging portion that forms the internal space from sinking due to gravity as the final shape. In this case, the optimization objective related to the internal space can be, for example, optimizing the strength and shape of the wall that forms the internal space, and the first region can be set to, for example, the periphery including the wall of the internal space. This makes it possible to perform topology optimization based on the optimization objective of the strength and shape of the support member that supports the wall in the development view data in which the periphery is developed.

In addition, in the present example, the first variant, the second variant, and the third variant described above, the region expansion unit 72 expands the first region R1 two-dimensionally so that the inlet I and the outlet O that are ultimately set are located at both ends. However, the two-dimensional first region R1 expanded by the region expansion unit 72 can also be expanded, for example, so that the inlet I and the outlet O that are ultimately set are located in the center. In this case, the flow path structure design unit 73 designs a flow path structure in which the inlet I and the outlet O are located in the center in the optimization process.

In addition, in the above-mentioned present example, the first variant, the second variant, and the third variant, additive manufacturing is performed using metal powder S as the material powder. The material powder is not limited to metal powder, and additive manufacturing is also possible using, for example, resin powder.

Furthermore, in the above-mentioned present example, the first variant, the second variant, and the third variant, the additive manufacturing of the additive product W is illustrated using the additive manufacturing apparatus 1 of the powder bed fusion method. However, instead of additively manufacturing the additive product W using the additive manufacturing apparatus 1 of the powder bed fusion method, it is also possible to additively manufacture an additive product having an internal space using an additive manufacturing apparatus of the energy deposition method.

1...additive manufacturing device, 10...chamber, 20...additive product support device, 21...additive manufacturing container, 22...lifting table, 23...base, 30...powder supply device, 31...powder storage container, 32...supply table, 33...recoater, 40...light beam irradiation device, 40a...light beam, 41...laser oscillator, 42...laser head, 43...optical fiber, 50...heating device, 60...control device, 61...data storage unit, 62...lifting table operation control unit, 63...powder supply control unit, 64...light beam irradiation control unit, 65...heating control unit, S...metal powder (material powder), W...additive product, W1...temporary additive product, 70...optimal shape design device, 71 ...Area setting section, 72...Area expansion section, 73...Flow path structure design section, 74...Coordinate data generation section, 75...Three-dimensional model generation section, 76...Final shape design section, 77...Database, H...Recess, R1...First area, R2...Second area, R3...Third area, R4...Fourth area, T...Internal piping (internal space), T1...First piping, T11, T12...Circulation section, T2...Second piping, T21, T22...Circulation section, T3...Inlet piping, T4...Outlet piping, I...Inlet, O...Outlet, OZ...Expanded view data, OZ1...Expanded view data, Z...Flow path structure, Z1...Flow path structure, ZD...Coordinate data, ZD1...Coordinate data, M...Three-dimensional model, SD...Shape data

Claims (25)

A method for designing an additive product that is additively manufactured to have an internal space by an additive manufacturing device that irradiates a material powder with a light beam and melts and solidifies the material powder to perform additive manufacturing, comprising:
A region setting process for setting a curved surface including the internal space of the additive product to be additively manufactured, the curved surface being a quadrangle when expanded two-dimensionally ;
a conversion step of converting the curved surface set in the area setting step into development data in a quadrangle ;
an optimization step of performing topology optimization based on a predetermined optimization objective on the development data converted in the conversion step;
a reconversion step of reconverting the two-dimensional data subjected to the topology optimization in the optimization step into three-dimensional data;
A method for designing additive manufacturing products by performing the steps listed below in sequence. The method for designing an additive manufacturing object according to claim 1 , wherein the curved surface set in the region setting step includes at least a portion of a peripheral surface of a tube. The method for designing an additive manufactured product according to claim 1 or 2 , further comprising the step of: executing a shape optimization step of optimizing a shape of the internal space in the three-dimensional data reconverted in the reconversion step. the internal space has an inlet through which a fluid flows and an outlet through which the fluid flows, and is a flow path through which the fluid flows from the inlet to the outlet,
The curved surface set in the region setting step includes the inlet and the outlet, and is a surface along the flow path from the inlet to the outlet . The design method for an additive manufacturing product according to any one of claims 1 to 3. The flow path is a cooling path that is disposed adjacent to a cooling target portion in the additive product and through which a cooling medium for cooling the cooling target portion flows as the fluid,
The optimization objective is:
related to the properties of the fluid flowing through the internal space ,
The method for designing an additive manufactured product according to claim 4, further comprising minimizing variation in at least one of the cooling characteristics of the cooling medium flowing through the flow path, the flow velocity of the cooling medium, and the flow rate of the cooling medium. the additive product is a mold having the cooling passages;
The method for designing an additive manufactured product according to claim 5 , wherein the cooling target is a cavity formed in the mold and into which molten material is supplied. The cavity has a cylindrical shape with a bottom,
The method for designing an additive manufactured product according to claim 6 , wherein the cooling passage is designed to have a curved shape along a circumferential surface of a cylindrical portion of the cavity. The additive product is a main shaft of a machine tool having the cooling passage and including a rotating member and a housing having a cylindrical portion through which the rotating member is inserted,
The method for designing an additive manufactured product according to claim 5 , wherein the cooling target portion is the cylindrical portion. The method for designing an additive manufacturing product according to claim 8, wherein the cooling passage is designed to have a curved shape that follows the circumferential surface of the cylindrical portion. 6. The method for designing an additive manufactured product according to claim 5 , wherein the optimization objective is further to minimize a pressure loss of the cooling medium flowing through the flow passage at least at a position including the inlet and the outlet . the additive product is a mold having the cooling passages;
The method for designing an additive manufactured product according to claim 10 , wherein the cooling target is a cavity formed in the mold and into which molten material is supplied. The cavity has a cylindrical shape with a bottom,
The method for designing an additive manufactured product according to claim 11 , wherein the cooling passage is designed to have a curved shape along a circumferential surface of a cylindrical portion of the cavity. The additive product is a main shaft of a machine tool having the cooling passage and including a rotating member and a housing having a cylindrical portion through which the rotating member is inserted,
The method for designing an additive manufactured product according to claim 10 , wherein the part to be cooled is the cylindrical part. The method for designing an additive manufactured product according to claim 13 , wherein the cooling passage is designed to have a curved shape along a circumferential surface of the cylindrical portion. The method for designing an additive product described in any one of claims 1 to 14 , wherein the additive manufacturing device irradiates a light beam onto the evenly spread material powder, melting and solidifying the material powder to perform additive manufacturing. An additive manufacturing device that performs additive manufacturing by irradiating a material powder with a light beam and melting and solidifying the material powder, and designs an additive manufacturing product that is additively manufactured to have an internal space ,
A region setting unit that sets a curved surface including the internal space of the additive product to be additively manufactured, the curved surface being a quadrangle when expanded two-dimensionally ;
an area development unit for converting the curved surface set by the area setting unit into development data in which the curved surface is developed into a quadrangle ;
an optimization unit that performs topology optimization on the development data converted by the region expansion unit based on a predetermined optimization objective;
a reconversion unit that reconverts the two-dimensional data that has been subjected to the topology optimization by the optimization unit into three-dimensional data;
An additive manufacturing design device comprising: The additive manufacturing design device according to claim 16 , wherein the curved surface set by the region setting unit includes at least a portion of a circumferential surface of a cylinder. The additive manufacturing product design device according to claim 16 or 17 , further comprising a shape optimization unit that performs shape optimization on a shape of the internal space in the three-dimensional data reconverted by the reconversion unit . the internal space has an inlet through which a fluid flows and an outlet through which the fluid flows , and is a flow path through which the fluid flows from the inlet to the outlet,
The flow path is a cooling path that is disposed adjacent to a cooling target portion in the additive product and through which a cooling medium for cooling the cooling target portion flows as the fluid,
the curved surface set by the region setting unit is a surface that includes the inlet and the outlet and extends along the flow path,
The optimization objective is:
related to the properties of the fluid flowing through the internal space,
The design device for additive manufactured products according to any one of claims 16 to 18 , wherein the variation in at least one of the cooling characteristics of the cooling medium flowing through the flow path, the flow velocity of the cooling medium, and the flow rate of the cooling medium is minimized. 20. The apparatus for designing an additive product according to claim 19 , wherein the optimization objective is further to minimize pressure loss of the cooling medium flowing through the flow passage at least at locations including the inlet and the outlet. The additive manufacturing device is an additive manufacturing device described in any one of claims 16 to 20 , which irradiates a light beam onto the evenly laid out material powder, melting and solidifying the material powder to perform additive manufacturing. A design process according to the method for designing an additive manufactured product according to any one of claims 1 to 15;
A manufacturing method for an additive product, comprising:
The additive product is a mold having a flow path for a fluid to flow through and a cavity into which a molten material is supplied;
The manufacturing process includes:
supplying the material powder;
irradiating the powdered material with the light beam;
melting the powder of material with the light beam;
solidifying the molten powder of material;
A method for manufacturing an additive product comprising : The cavity has a cylindrical shape with a bottom,
The method for manufacturing an additive product according to claim 22, wherein the flow path is a cooling path through which a cooling medium for cooling the cavity, which is a cooling target portion in the mold, is circumferentially designed in a curved shape along a circumferential surface of a cylindrical portion in the cavity . A design process according to the method for designing an additive manufactured product according to any one of claims 1 to 15;
A manufacturing method for an additive product, comprising:
The additive product is a main shaft of a machine tool having a flow path for flowing a fluid , and including a rotating member and a housing having a cylindrical portion through which the rotating member is inserted ,
The manufacturing process includes:
supplying the material powder;
irradiating the powdered material with the light beam;
melting the powder of material with the light beam;
solidifying the molten powder of material;
A method for manufacturing an additive product comprising : The method for manufacturing an additive product according to claim 24, wherein the flow path is a cooling path through which a cooling medium flows for cooling the cylindrical portion, which is a cooling target portion of the spindle, and is designed to have a curved shape along a circumferential surface of the cylindrical portion .

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