Method and device for performing additive manufacturing while rotating a spindle

An additive manufacturing method includes forming a shaped body by repeating: a material feeding step of forming a powder layer by feeding a shaping material that includes a metal powder onto a base that is provided outside a spindle in a radial direction thereof while rotating the spindle provided to be rotatable about a center axis; and a beam irradiating step of solidifying the shaping material by irradiating a prescribed area of the powder layer with a beam.

TECHNICAL FIELD

The present invention relates to an additive manufacturing method and an additive manufacturing device.

BACKGROUND ART

For example, an impeller used in a rotating machine such as a centrifugal compressor includes a disk, blades, and a cover. The disk is fixed to a rotating shaft provided in a rotating machine. The plurality of blades are provided on a surface of the disk at intervals in a circumferential direction. The cover covers these blades from a side opposite from the disk. The impeller serves as a flow path through which a fluid flows between the disk, the cover, and the blades adjacent to each other in the circumferential direction.

For example, Patent Document 1 discloses a method for forming an impeller using an additive manufacturing method. The additive manufacturing method includes sintering a metal powder placed in accordance with a desired shape of the impeller using thermal energy such as a laser or an electron beam. By sequentially repeating steps such as placement and sintering of the metal powder, the sintered metal powder is laminated to form an impeller having a desired shape.

CITATION LIST

Patent Literature

Patent Document 1

SUMMARY OF INVENTION

Technical Problem

A flow path having a complicated curved surface therein is formed in the impeller. In the additive manufacturing method, because a metal is laminated from the lower side to the upper side, it is difficult to form a complicated curved surface in accordance with an inclination angle. On the other hand, in order to form a complicated curved surface using the additive manufacturing method, it is conceivable to incline the attitude of the impeller during additive manufacturing. However, as a result of setting the attitude of the impeller so that a specific part can be shaped, it may be difficult to form other parts in some cases. In this way, there is demand to improve the formability when shaping a shaped body having a complicated shape like an impeller by additive manufacturing.

The present invention is for the purpose of providing an additive manufacturing method and an additive manufacturing device capable of improving the moldability of a shaped body having a complicated shape.

Solution to Problem

An additive manufacturing method according to a first aspect of the present invention includes: forming a shaped body by repeating: a material feeding step of forming a powder layer by feeding a shaping material which includes a metal powder onto a base which is provided outside a spindle in a radial direction thereof while rotating the spindle provided to be rotatable about a center axis; and a beam irradiating step of solidifying the shaping material by irradiating a prescribed area of the powder layer with a beam.

According to such a constitution, it is possible to form members such as disk-like, annular, and tubular members by sequentially performing additive manufacturing while rotating a spindle. Even when the shaped body has portions which extend greatly in a direction intersecting a central axis direction of the spindle like a disk and a cover of an impeller therein, by performing additive manufacturing while rotating, it is possible to perform the additive manufacturing of these parts from the inside toward the outside in the radial direction. Thus, it is possible to mold a shaped body having a complicated shape which has been conventionally difficult to form.

According to an additive manufacturing method according to a second aspect of the present invention, in the first aspect, the material feeding step may include rotating the spindle over a rotation angle of a beam width or less of the beam.

According to such a constitution, when the step of radiating the beam for melting the shaping material is repeated, the irradiation ranges of the beams overlap each other. Thus, it is possible to melt the fed mold material while rotating the spindle without seams to form the shaped body. Therefore, it is possible to obtain a uniform shaped body.

In an additive manufacturing method according to a third aspect of the present invention, in the first or second aspect, the shaping material may be in a slurry state having a viscosity within a prescribed range.

According to such a constitution, it is possible to prevent the shaping material fed to the base from flowing downward in the vertical direction when the spindle rotates.

In an additive manufacturing method according to a fourth aspect of the present invention, in any one of the first to third aspects, the material feeding step may include forming the powder layer, using an outer circumferential surface of a core member which is in a tubular shape installed in the spindle and forms a part of the shaped body, as the base.

According to such a constitution, by forming the shaping material on the core member installed in the spindle, it is possible to form the shaping material satisfactorily using this core member as the base.

In an additive manufacturing device according to a fifth aspect of the present invention, an additive manufacturing device includes: a spindle provided to be rotatable about a center axis; a spindle driving unit which is configured to rotate the spindle; a material feeding unit which is configured to feed a shaping material containing a metal powder onto a base provided outside the spindle in a diameter direction to form a powder layer; and a beam irradiation unit which is configured to irradiate a prescribed area of the powder layer formed by the material feeding unit with a beam for solidifying the shaping material.

According to such a constitution, the shaping material is fed onto the base by the material feeding unit while the spindle is rotated by the spindle driving unit. By radiating a beam using the beam irradiation unit, the fed shaping material is solidified. Thus, the metal layer which constitutes a part of the shaped body is formed. Therefore, by laminating metal layers to be sequentially formed in the circumferential direction outside of the spindle in the radial direction from the inside thereof in the radial direction toward the outside thereof, it is possible to form the shaped body.

In an additive manufacturing device according to a sixth aspect of the present invention, in the fifth aspect, the additive manufacturing device may further include a film thickness adjustment unit which is configured to adjust a film thickness of the powder layer formed by the material feeding unit.

According to such a constitution, it is possible to increase or decrease a film thickness of the shaping material to be formed through one instance of additive manufacturing.

Advantageous Effects of Invention

According to the present invention, it is possible to improve the moldability of a shaped body having a complicated shape.

DESCRIPTION OF EMBODIMENTS

An additive manufacturing method and an additive manufacturing device of the present invention will be described with reference to the drawings.FIG. 1is a diagram of an impeller produced through the additive manufacturing method according to an embodiment of the present invention viewed in an axial direction of the impeller.FIG. 2is a cross-sectional view of the impeller shown inFIG. 1viewed in a cross section taken along an axis line of the impeller.

In the additive manufacturing method and the additive manufacturing device according to this embodiment, for example, an impeller installed in a rotating machine such as a centrifugal compressor is formed as a shaped body. The impeller manufactured in this embodiment is installed in, for example, a rotating machine such as a centrifugal compressor. As shown inFIGS. 1 and 2, an impeller1includes a disk2, blades3, and a cover4.

The disk2is substantially circular when viewed in an axis line O direction in which an axis line O extends. The disk2is formed in a circular disc shape centered on the axis line O. To be more specific, the disk2is formed so that a dimension of the disk2in a radial direction Dr centered on the axis line O gradually increases from an end portion2aon a first side (the upper side inFIG. 2) thereof in the axis line O direction toward an end portion2bon a second side (the lower side inFIG. 2) thereof. The disk2has a curved surface23curved to be recessed toward the second side (the end portion2bside) thereof in the axis line O direction as a surface facing the first side (the end portion2aside) thereof in the axis line O direction.

Also, a shaft insertion hole11passing through in the axis line O direction is provided in a center of the disk2. A rotating shaft (not shown) of the rotating machine is inserted into the shaft insertion hole11in the axis line O direction. Thus, the impeller1is rotatable integrally with the rotating shaft of the rotating machine.

Each of the blades3is formed to rise from the curved surface23of the disk2to the first side thereof in the axis line O direction. The plurality of blades3are formed at intervals in a circumferential direction Dc centered on the axis line O with respect to the curved surface23. Each of the blades3extends away from the disk2and is formed to extend outward from an inside (the shaft insertion hole11side) of the disk2in the radial direction Dr.

The cover4is provided to have a space in the axis line O direction with respect to the curved surface23of the disk2. The cover4is provided to cover the plurality of blades3from the first side in the axis line O direction. The cover4has a circular disk shape centered on the axis line O. To be specific, the cover4has an umbrella shape whose diameter gradually decreases from the second side toward the first side in the axis line O direction. An inner circumferential end portion41in the cover4is disposed such that there is a space between the inner circumferential end portion41and the end portion2aof the disk2in the radial direction Dr. Thus, between the inner circumferential end portion41of the cover4and the end portion2aof the disk2, an opening is provided toward the first side in the axis line O direction. Furthermore, the cover4is provided to have a space in the axis line O direction between the cover4and the end portion2bof the disk2. Thus, between an outer circumferential end portion42of the cover4and the end portion2bof the disk2, an opening is provided outward in the radial direction Dr.

Flow paths12are formed inside the impeller1by the disk2, the cover4, and the blades3. The flow paths12are defined by the blades3adjacent to each other in the circumferential direction Dc between the disk2and the cover4. The impeller1has a plurality of flow paths12in the circumferential direction Dc. Each of the flow paths12has a flow path inlet12awhich opens toward the first side in the axis line O direction between the end portion2aof the disk2and the inner circumferential end portion41of the cover4. Furthermore, each of the flow paths12has a flow path outlet12bwhich opens outward in the radial direction Dr between the end portion2bof the disk2and the outer circumferential end portion42of the cover4. Furthermore, an inner circumferential surface of the flow path12is constituted of the curved surface23of the disk2, a surface facing the second side (opposite to the first side) of the cover4in the axis line O direction, and a surface of the blade3facing in a circumferential direction.

A gap between the disk2and the cover4is formed to gradually decrease from an inside toward an outside in the radial direction Dr. Furthermore, a gap in the circumferential direction Dc between the blades3adjacent to each other in the circumferential direction Dc is formed to gradually increase from the flow path inlet12atoward the flow path outlet12b. Each of the flow paths12is formed so that its flow path cross-sectional area gradually decreases from the flow path inlet12atoward the flow path outlet12b.

An additive manufacturing device100used for forming the impeller1will be described below.FIG. 3is a front view of the additive manufacturing device according to the embodiment of the present invention viewed in a center axis direction of a spindle.FIG. 4is a cross-sectional view of the additive manufacturing device shown inFIG. 3taken along the center axis of the spindle.FIG. 5is a block diagram showing a constitution of a functional unit of the additive manufacturing device shown inFIGS. 3 and 4.

In the additive manufacturing device100shown inFIGS. 3 to 5, the impeller1described above is formed by the additive manufacturing method. In the additive manufacturing device100, a metal layer202extending in the circumferential direction Dc is laminated from the inside toward the outside in the radial direction Dr, thereby forming the impeller1symmetrically formed with the axis line O as a center thereof.

The additive manufacturing device100includes a spindle device110, a material feeding unit120, a film thickness adjustment unit130, a beam irradiation unit140, a brush device150, and a control unit160.

The spindle device110includes a spindle driving unit111(refer toFIG. 5) and the spindle112.

The spindle112is provided to be rotatable about its center axis Ac (in the circumferential direction Dc). The spindle112in this embodiment has a columnar shape extending in a horizontal direction Dh. The spindle112is driven to be rotatable about a center axis Ac using the spindle driving unit111(refer toFIG. 5) such as a motor. A core member203is provided as a base outside the spindle112in the radial direction Dr.

It should be noted that, although the spindle112in this embodiment is disposed so that the center axis Ac extends in the horizontal direction Dh, the center axis Ac is not limited to being disposed to be orthogonal to a vertical direction Dv in this way. For example, the spindle112may be disposed so that the center axis Ac is inclined with respect to the vertical direction Dv.

The spindle driving unit111rotates the spindle112about the center axis Ac. In the spindle driving unit111, the conditions for rotating the spindle112such as a rotation speed and a rotation angle are controlled by the control unit160.

The core member203has a cylindrical shape. The core member203has the spindle112inserted therein and is fixed to be immovable about the center axis Ac with respect to the spindle112, for example, through shrinkage fitting or the like and in the center axis Ac direction (a width direction Dw). The core member203forms a part of the impeller1to be formed. The core member203in this embodiment may be formed of the same material as the impeller1.

It should be noted that the core member203is not limited to being formed of the same material as the impeller1. For example, when a base material (the impeller1formed through additive manufacturing) is formed of a material having a poor shrinkage fitting property, the core member203may be formed of a material having a good shrinkage fitting property different from that of the base material.

The material feeding unit120feeds a shaping material200including a metal powder onto the core member (a base)203provided outside the spindle112in the radial direction Dr to form a powder layer201. The material feeding unit120feeds the shaping material200onto the core member203to form the powder layer201in a tangential direction with respect to an outer circumferential surface of the spindle112. The material feeding unit120in this embodiment includes a storage tank121and a tank moving mechanism122(refer toFIG. 5).

The storage tank121stores the shaping material200which contains a metal powder used in the additive manufacturing method. Here, in this embodiment, as the shaping material200, a slurry-like (paste-like) shaping material obtained by dispersing a metal powder in a dispersion medium and having a viscosity within a prescribed range set in advance is used. Here, the viscosity within a prescribed range is a viscosity of an extent at which the shaping material200before being solidified does not fall off the rotating core member203downward in the vertical direction Dv. The storage tank121includes an opening portion123on a side thereof close to the spindle112. The storage tank121is provided to be movable in the horizontal direction Dh relatively with respect to the spindle112.

The tank moving mechanism122moves the storage tank121with respect to the spindle112. The tank moving mechanism122moves the position of the storage tank121in the horizontal direction Dh. The tank moving mechanism122adjusts the position of the storage tank121so that the opening portion123is pressed against a material feeding site P1to which the shaping material200is to be fed outside in the radial direction Dr of the spindle112.

The material feeding unit120feeds the shaping material200stored in the storage tank121to the material feeding site P1outside in the radial direction Dr of the spindle112through the opening portion123.

It should be noted that, although the material feeding unit120in this embodiment has a structure in which the material feeding unit120directly feeds the shaping material200from the storage tank121to the material feeding site P1via the opening portion123, the material feeding unit120is not limited to such a structure. For example, the material feeding unit120may have a structure in which the material feeding unit120includes a part for feeding other shaping materials200such as a brush and a nozzle connected to the storage tank121and indirectly feeds the shaping material200from the storage tank121to the material feeding site P1.

The film thickness adjustment unit130adjusts a film thickness of the powder layer201formed using the material feeding unit120. The film thickness adjustment unit130in this embodiment includes an adjusting blade131and a blade moving mechanism132(refer toFIG. 5).

The adjusting blade131is disposed on a downstream side in a rotating direction R of the spindle112with respect to the opening portion123of the storage tank121in the material feeding unit120. The adjusting blade131has a plate shape. A lower end portion131aof the adjusting blade131comes into contact with the shaping material200fed to the material feeding site P1. The adjusting blade131is provided to be movable in the vertical direction Dv relatively with respect to the spindle112.

The blade moving mechanism132moves the adjusting blade131in the vertical direction Dv. The blade moving mechanism132can change the film thickness of the powder layer201by moving the position of the lower end portion131ain the adjusting blade131with respect to an outer circumferential surface of the core member203.

The film thickness adjustment unit130adjusts the position of the adjusting blade131using the blade moving mechanism132when the shaping material200fed to the material feeding site P1integrally rotates with the spindle112. By bringing the surface of the powder layer201into contact with the lower end portion131aof the adjusting blade131whose position has been adjusted, the surface of the powder layer201is smoothly leveled and the film thickness of the powder layer201is adjusted.

The beam irradiation unit140irradiates a prescribed area of the powder layer201formed using the material feeding unit120with a beam B for solidifying the shaping material200. The beam irradiation unit140in this embodiment includes a beam nozzle141, a beam moving mechanism143(refer toFIG. 5), and a focal position adjusting unit144(refer toFIG. 5).

The beam nozzle141is disposed on the downstream side in the rotating direction R of the spindle112with respect to the adjusting blade131. In this embodiment, the beam nozzle141is disposed above the center axis Ac of the spindle112in the vertical direction Dv. The beam nozzle141irradiates the shaping material200with the beam B such as a laser or an electron beam supplied from a beam source (not shown) at an irradiation site P2below the beam nozzle141in the vertical direction Dv.

As shown inFIG. 4, the beam moving mechanism143moves the beam nozzle141in the width direction Dw along the center axis Ac of the spindle112. Furthermore, the beam moving mechanism143moves the beam nozzle141in the vertical direction Dv and moves the beam nozzle141relative to an outer circumferential surface of the spindle112.

The focal position adjusting unit144adjusts the focal position of the beam B radiated to the shaping material200through the beam nozzle141.

The beam irradiation unit140radiates the beam B through the beam nozzle141whose position in the vertical direction Dv has been adjusted using the beam moving mechanism143. The beam irradiation unit140irradiates the powder layer201with the beam B at the irradiation site P2located at the uppermost position in the circumferential direction Dc of the spindle112. The shaping material200is sintered and solidified when irradiated with the beam B. The beam irradiation unit140irradiates the shaping material200only in a portion in which the impeller1is to be formed with the beam B while the beam nozzle141is moved by the beam moving mechanism143in the width direction Dw. After the irradiation with the beam B, the shaping material200is solidified to form the metal layer202.

The brush device150is provided on the downstream side in the rotating direction R of the spindle112relative to the beam nozzle141and on an upstream side in the rotating direction R of the spindle112relative to the storage tank121. The brush device150removes portions solidified and protruding from the surface of the metal layer202. The brush device150in this embodiment includes a brush moving mechanism151and a brush main body152.

The brush main body152has a distal end portion which is in contact with the surface of the metal layer202outside the spindle112in the radial direction Dr.

The brush moving mechanism151moves relative to the brush device150in the horizontal direction Dh with respect to the spindle112. The brush moving mechanism151adjusts the position of the brush device150so that a distal end portion of the brush device150is pressed against the metal layer202.

As shown inFIG. 5, the control unit160controls the operations of the spindle driving unit111, the tank moving mechanism122, the blade moving mechanism132, the beam moving mechanism143, the focal position adjusting unit144, and the brush moving mechanism151on the basis of a preset computer program. For example, the control unit160sends an instruction to the spindle driving unit111to cause the spindle driving unit111to rotate the spindle112in accordance with the irradiation state of the beam B. The control unit160sends an instruction to the tank moving mechanism122to cause the tank moving mechanism122to move the storage tank121in accordance with the rotation state of the spindle112. The control unit160sends an instruction to the blade moving mechanism132to cause the blade moving mechanism132to move the adjusting blade131in accordance with the rotation state of the spindle112. The control unit160sends an instruction to the beam moving mechanism143to cause the beam moving mechanism143to move the beam nozzle141in accordance with the rotation state of the spindle112. The control unit160sends an instruction to the focal position adjusting unit144to cause the focal position adjusting unit144to adjust the focal position of the beam nozzle141in accordance with the rotation state of the spindle112. The control unit160sends an instruction to the brush moving mechanism151to cause the brush moving mechanism151to move the brush main body152in accordance with the rotation state of the spindle112.

The additive manufacturing method of the impeller1using the additive manufacturing device100as described above will be described below. The additive manufacturing method of the impeller1which will be shown below is automatically executed in the additive manufacturing device100by the control unit160which performs control based on a preset computer program. It should be noted that the additive manufacturing method of the impeller1may be carried out without using the additive manufacturing device100in this embodiment.

FIG. 6is a flowchart showing a flow of the additive manufacturing method according to this embodiment of the present invention. As shown inFIG. 6, the additive manufacturing method of the impeller1in this embodiment includes a core member setting step S1, a material feeding step S2, and a beam irradiating step S3.

As shown inFIGS. 3 and 4, in the core member setting step S1, the core member203which forms a part of the impeller1is installed in the spindle112. In the core member setting step S1in this embodiment, the core member203is prepared in advance. The prepared core member203is fixed in a state in which an inner circumferential surface is in contact with the outer circumferential surface of the spindle112. Thus, the outer circumferential surface of the core member203serves as a base.

In the material feeding step S2, the powder layer201is formed on the base while rotating the spindle112. In the material feeding step S2in this embodiment, the powder layer201is formed using the outer circumferential surface of the core member203installed in the spindle112in the core member setting step S1as the base. In the material feeding step S2, the shaping material200is fed above a center of the core member203installed in the spindle112in the vertical direction Dv through the material feeding unit120.

Here, when a material is fed by the material feeding unit120, the opening portion123of the storage tank121is pressed against the material feeding site P1while rotating the spindle112by a prescribed angle in the rotating direction R. The shaping material200stored in the storage tank121is pressed against the material feeding site P1through the opening portion123and adheres thereto. In this state, when the spindle112rotates, the powder layer201is formed on the outer circumferential surface of the core member203. Thus, the shaping material200is fed in a band shape continuously in the rotating direction R of the spindle112, that is, in the circumferential direction Dc with a width having the same dimension as an opening dimension of the opening portion123in the width direction Dw at the material feeding site P1.

At that time, the shaping material200is in a slurry state having a prescribed viscosity. Thus, the fed shaping material200at the material feeding site P1is prevented from flowing downward in the vertical direction Dv.

Thus, the fed shaping material200moves to the downstream side in the rotating direction R with the rotation of the spindle112. The powder layer201has a surface leveled by the adjusting blade131of the film thickness adjustment unit130and is formed to have a prescribed film thickness.

The beam irradiating step S3irradiates a prescribed area of the powder layer201with a beam to solidify the shaping material200. The beam irradiating step S3in this embodiment is performed on the powder layer201whose film thickness is adjusted by the film thickness adjustment unit130and which reaches the irradiation site P2due to the rotation of the spindle112. In the beam irradiating step S3, the beam B is radiated through the beam nozzle141of the beam irradiation unit140.

At this time, the beam irradiation unit140moves the beam nozzle141using the beam moving mechanism143in the width direction Dw along the center axis Ac of the spindle112in accordance with a cross-sectional shape of the impeller1to be formed. Moreover, only a position in which each part of the impeller1is to be formed is irradiated with a beam through the beam nozzle141. That is to say, the beam irradiation of the beam irradiation unit140stops at a portion in which the impeller1is not formed. Thus, the shaping material200solidifies only at a site at which the impeller1is to be formed in the width direction Dw and the metal layer202is formed.

Here, when the beam B is radiated while moving the beam B in the width direction Dw, the rotation of the spindle112is stopped. That is to say, the spindle112rotates during material feeding in the material feeding step S2and stops while the beam B is radiated in the beam irradiating step S3. In other words, the spindle112rotates intermittently.

Upon completion of the beam irradiating step S3of radiating the beam B, the control unit160determines whether the shaping of the impeller1is completed and checks the determination (determination step S4). When the shaping of the impeller1is not completed, the process returns to the process of the material feeding step S2. That is to say, the material feeding step S2and the beam irradiating step S3are repeated until the shaping of the impeller is completed.

As a result, the metal layer202extends in the circumferential direction Dc outside the core member203in the radial direction Dr. After that, the plurality of metal layers202are repeatedly formed over the circumference outward in the radial direction Dr of the core member203. Thus, the metal layers202are sequentially laminated from the inside to the outside in the radial direction Dr on the outer circumferential surface of the core member203. In this way, the impeller1is formed of the metal layers202sequentially formed in the circumferential direction Dc.

Incidentally, in the material feeding step S2, it is desirable that a rotation angle at which the spindle112is rotated while feeding the shaping material200be a rotation angle which is a beam width or less of the beam B to be radiated in the beam irradiating step S3. Thus, in the rotating direction R (the circumferential direction Dc) of the spindle112, it is possible to form the metal layer202by melting the fed shaping material200seamlessly.

Also, by repeating the material feeding step S2and the beam irradiating step S3, the metal layers202are laminated from the inside toward the outside in the radial direction Dr. As the metal layers202are laminated in the radial direction Dr, the outer diameter of the impeller1in the course of being formed gradually increases. Accordingly, the positions of the material feeding site P1and the irradiation site P2also move outward in the radial direction Dr. Thus, under the control of the control unit160, the storage tank121is moved outward in the radial direction Dr using the tank moving mechanism122. Similarly, under the control of the control unit160, the adjusting blade131, the beam nozzle141, and the brush main body152are moved outward in the radial direction Dr using the blade moving mechanism132, the beam moving mechanism143, and the brush moving mechanism151.

Also, when it is necessary to change the thickness of the metal layer202to be formed, in the film thickness adjustment unit130, it is possible to adjust the position of the adjusting blade131using the blade moving mechanism132. At that time, the control unit160adjusts the focal position of the beam B radiated through the beam nozzle141by the focal position adjusting unit144in accordance with the position (an estimated value of a film thickness of the shaping material200) of the adjusting blade131adjusted by the blade moving mechanism132.

When it is determined in the determination step S4that the shaping of the impeller1has been completed, the additive manufacturing device100ends a series of additive manufacturing operations. After that, by removing the core member203from the spindle112, performing heat treatment, and polishing treatment on a surface, and the like, as necessary, the impeller1is completed.

As described above, when the impeller1is formed by the additive manufacturing device100using the additive manufacturing method, the disk2, the blades3, and the cover4constituting the impeller1are formed by sequentially laminating the metal layers202from the inside toward the outside in the radial direction Dr.

According to the additive manufacturing method and the additive manufacturing device100in the above-described embodiment, the disk2and the cover4extending in a direction which intersects the center axis Ac direction of the spindle112can be formed to be laminated from the bottom to the top. Thus, it is possible to mold the impeller1having a complicated shape which has been conventionally difficult to form. Furthermore, even with the impeller1having a small gap between the disk2and the cover4and having a narrow flow path12, it is possible to perform shaping by performing additive manufacturing from the inside in the radial direction Dr toward the outside in the radial direction Dr.

Also, the impeller1formed by performing additive manufacturing while rotating the spindle112has a high uniformity in the circumferential direction. Therefore, a crystal growth direction of a metal forming the impeller1is a direction in which the metal extends from the center axis Ac of the impeller1outward in the radial direction Dr. Thus, it is possible to reduce the anisotropy in the strength of the impeller1with respect to a centrifugal direction.

Thus, it is possible to form the impeller1having a complicated shape and it is possible to form the impeller1having a uniform strength distribution in the circumferential direction.

In addition, it is possible to reduce the number of positions in which a support for supporting the disk2and the cover4in the flow path12is formed during additive manufacturing. Thus, it is easier to form the impeller1having a complicated shape.

Also, the spindle112is intermittently rotated over a rotation angle of the beam width or less of the beam B. Thus, the impeller1can be formed by melting the fed shaping material200while rotating the spindle112without seams. Therefore, a uniform impeller1can be obtained.

Also, the shaping material200is in a slurry state having a viscosity within a prescribed range. Thus, it is possible to prevent the shaping material200fed to the upper side of the spindle112from flowing downward. Therefore, the additive manufacturing can be performed while rotating with high accuracy.

Also, by forming the shaping material200on the core member203installed in the spindle112, it is possible to efficiently form the impeller1using this core member203as a base material.

Since the above-described additive manufacturing device100includes the film thickness adjustment unit130, it is possible to increase or decrease a film thickness of the metal layer202to be formed through one instance of additive manufacturing. In addition, the focal position of the beam B can be adjusted by the focal position adjusting unit144in accordance with the film thickness of the shaping material200adjusted by the film thickness adjustment unit130. Thus, it is possible to melt the shaping material200satisfactorily even when the film thickness is increased or decreased.

Although the embodiments of the present invention have been described in detail above with reference to the drawings, the constitutions in the embodiments, the combinations thereof, and the like are merely examples, and additions, omissions, substitutions, and other modifications to the constitutions are possible without departing from the gist of the present invention. Furthermore, the present invention is not limited by the embodiments, but is limited only by the claims.

For example, although the tubular core member203is provided in the spindle112in the above-described embodiments, the constitution of the core member203is not limited at all. For example, a solid columnar core member may be integrally formed with the spindle112and additive manufacturing may be performed on an outer circumferential surface of this core member. In this case, the outer circumferential surface of the spindle112is substantially the base. Such a solid columnar core member can serve as, for example, the rotating shaft of the impeller1. That is to say, the impeller1and the rotating shaft can be integrally formed by additive manufacturing.

Also, an irradiation direction of the beam B radiated through the beam nozzle141is not limited to a direction centered on the center axis Ac of the spindle112. For example, by inclining the beam nozzle141or by offsetting the beam nozzle141laterally from the center axis Ac, the surface of the shaping material200at the irradiation site P2may be irradiated with the beam B in the inclination direction.

Also, the center axis Ac of the spindle112may be inclined with respect to the horizontal direction Dh. In this case, it is desirable that the core member203reliably engage with the spindle112to prevent positional deviation of the core member203.

In addition, the additive manufacturing method and the additive manufacturing device100shown in the above-described embodiments can be applied not only to the impeller1but also to the shaping of axially symmetrical members such as other rotating bodies. Therefore, the additive manufacturing method and the additive manufacturing device100shown in the above-described embodiments can be applied not only to rotating bodies but also to the shaping of various members having an annular shape, a tubular shape, a circular disc shape, or the like.

Also, although the additive manufacturing device100in this embodiment has the constitution in which the position of the spindle112is fixed and the storage tank121, the adjusting blade131, the beam nozzle141, and the brush main body152are moved in accordance with the rotation state of the spindle112, the present invention is not limited to such a constitution. For example, the positions of the storage tank121and the adjusting blade131may be fixed and the position of the spindle112may be changed. At that time, it is desirable that the spindle112be movable in a normal direction of a line segment connecting the connecting points to the storage tank121and the adjusting blade131. Furthermore, the beam nozzle141and the brush main body152may be movable in accordance with a laminating thickness.

INDUSTRIAL APPLICABILITY

According to the above-described additive manufacturing method and additive manufacturing device, it is possible to form a shaped body having a complicated shape and it is possible to form a shaped body having a uniform strength distribution in a circumferential direction.

REFERENCE SIGNS LIST