Three-dimensional modeling apparatus and three-dimensional modeling method

A three-dimensional modeling apparatus includes a carrier configured to carry a modeling material, a device configured to cause the modeling material carried by the carrier to fly to the surface of an object, and an external force applying member configured to apply a predetermined external force to the modeling material when the modeling material is flying.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2020-026565, filed on Feb. 19, 2020, and Japanese Patent Application No. 2020-182382, filed on Oct. 30, 2020, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The disclosures herein relate to a three-dimensional modeling apparatus and a three-dimensional modeling method.

2. Description of the Related Art

As apparatuses for fabricating three-dimensional objects, additive manufacturing apparatuses utilizing techniques such as material extrusion (MEX), vat photopolymerization (VPP), powder bed fusion (PBF), material jetting (MJT), binder jetting (BJT), sheet lamination (SHL), and directed energy deposition (DED) are known.

Further, there is known an apparatus configured to cause a three-dimensional modeling material that absorbs light to fly to an object by emitting an optical vortex laser beam to the modeling material, thereby causing the modeling material to adhere to the object (see Patent Document 1, for example).

However, in the apparatus described in Patent Document 1, the flown modeling material is cured by ultraviolet irradiation after adhering to the object. Therefore, the modeling material may be dispersed when colliding with the object, and as a result, fabrication quality may be degraded.

Patent Documents

Patent Document 1: Re-publication of PCT International Publication No. 2016-136722

SUMMARY OF THE INVENTION

According to at least one embodiment, a three-dimensional modeling apparatus includes a carrier configured to carry a modeling material, a device configured to cause the modeling material carried by the carrier to fly to the surface of an object, and an external force applying member configured to apply a predetermined external force to the modeling material when the modeling material is flying.

DESCRIPTION OF THE EMBODIMENTS

It is a general object of the present invention to improve fabrication quality.

In the following, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, the same elements are denoted by the same reference numerals, and a duplicate description thereof may be omitted.

In the following embodiments, when a modeling material carried by a carrier is caused to fly to the surface of an object, a predetermined external force caused by an electric field, airflow, or gravity is applied to the flown modeling material. In this manner, variations in the landing position of the modeling material on the surface of the object due to inertia and variations in flying time can be reduced, thus improving fabrication quality.

First Embodiment

First, an apparatus for fabricating a three-dimensional object (hereinafter referred to as a “three-dimensional modeling apparatus100”) according to a first embodiment will be described with reference toFIG.1.FIG.1is a diagram illustrating an example configuration of the three-dimensional modeling apparatus100.

As illustrated inFIG.1, the three-dimensional modeling apparatus100includes a stage101, a stage heater102, a carrier111, a fixing member155, a supply device112, a flying laser115, a melting laser116functioning to apply energy, a cleaning blade117, and a collecting case118.

The stage101is a support member that supports an object200to be fabricated (an object in a fabrication process). The stage101can move back and forth in directions indicated by an arrow Y, and can also move up and down in directions indicated by an arrow Z at a pitch of 0.05 mm (modeling thickness), for example.

The stage heater102is disposed below the stage101, and the temperature of the stage101is controlled to match the temperature of a modeling material201.

The carrier111is an endless belt that circularly moves. Specifically, the carrier111is composed of a polyethylene terephthalate (PET) film (Lumirror, manufactured by Toray Industries, Inc.). Alternatively, the carrier111may be composed of a polyimide film (Kapton H, manufactured by Toray Industries, Inc.).

The carrier111is disposed above (on the upper side in the Z direction of) the stage101, and is stretched over rollers151and152and the fixing member155. The carrier111carries the particulate modeling material201, and conveys the modeling material201to a position above the object200on the stage101. However, the carrier111is not limited to the endless belt, and the carrier111may be a rotary drum that is composed of a cylindrical glass member and rotates in a direction (conveying direction) indicated by an arrow while carrying the modeling material201.

The fixing member155is a support member that supports the carrier111, and is disposed above the stage101at a position (fabrication position) where the object200is fabricated. A configuration and functions of the fixing member155will be described later in detail with reference toFIG.4.

The modeling material201can be appropriately selected depending on the object200. For example, the modeling material201may be a resin, such as polyamide 12 (PA 12), polybutylene terephthalate (PBT), polysulfone (PSU), polyamide 66 (PA 66), polyethylene terephthalate (PET), liquid crystal polymer (LCP), polyether ether ketone (PEEK), polyacetal (PON), polysulfone (PSF), polyamide 6 (PA 6), or polyphenylene sulfide (PPS). Further, the modeling material201is not limited to a crystalline resin, and may be an amorphous resin such as polycarbonate (PC), acrylonitrile butadiene styrene (ABS), or polyetherimide (PEI). Alternatively, the modeling material201may be a mixture of a crystalline resin and an amorphous resin.

Alternatively, the modeling material201may be any material other than a resin, such as metal, ceramic, or liquid. Further, the modeling material201may be a material having a viscosity greater than or equal to 1 Pascal-second (Pas).

In the present embodiment, the modeling material201is carried on the peripheral surface of the carrier111by the van der Waals force. If the resistance value of the modeling material201is high, the modeling material201can be carried only by electrostatic adhesion.

The supply device112is disposed on the carrier111, and is configured to supply the modeling material201to the peripheral surface (front surface) of the carrier111.

The supply device112includes a knurling roller123and a blade122. In addition, a contact roller124having a rubber layer on the surface thereof is disposed facing the knurling roller123.

The supply device112grinds and rubs the modeling material201with the blade122to loosen the aggregation of the modeling material201, and causes the modeling material201to pass through the knurling roller123, such that a thin layer of the modeling material201is formed on the peripheral surface of the carrier111.

However, the configuration of the supply device112is not limited to the above-described configuration using the knurling roller123, and a configuration using a mesh roller may be used. Alternatively, a contact supply method or a non-contact supply method using a rotating body, a mesh-based non-contact spray method, or a fluidized bed coating method in which powder particles are dispersed by air may be used.

The flying laser115functioning to cause the modeling material201to fly from the peripheral surface of the carrier111is disposed inside the carrier111.

The flying laser115is a pulsed laser, and irradiates the modeling material201with pulsed laser light115afrom the inside of the carrier111(the irradiation position corresponds to a “fabrication position”). The flying laser115is an example of a device configured to cause the modeling material201to fly.

By irradiating the modeling material201with the pulsed laser light115a, a force called radiation pressure is exerted on the modeling material201, thereby causing the adhesion force of the particulate modeling material201to be released. As a result, the modeling material201falls down by gravity. As is known, laser induced forward transfer (LIFT) as described in US006025110A is a non-contact technique that transfers a film material or a liquid material from a carrier to a receiver surface by laser irradiation. The material is locally heated and vaporized, and as a result, the material flies from the peripheral surface of the carrier in the direction of laser irradiation.

As used herein, the term “fly” means that the modeling material201is moved from the carrier111to the stage101side in a non-contact manner. Because the modeling material201can be moved in a non-contact manner instead of being transferred, the loss of the modeling material201can be reduced and the fabrication accuracy can be improved.

In the example ofFIG.1, the modeling material201is caused to fly in the direction of gravity toward the stage101. However, the modeling material201is not necessarily maintained at an angle of 90° with respect to the stage10when flying, and the modeling material201may be tilted at a desired angle with respect to the stage10when flying, as necessary.

In the present embodiment, it is not necessarily said that there is no contribution of the laser induced forward transfer technique. However, for the following reasons, the radiation pressure technique is mainly adopted.

1. The energy required to cause black powder, having a high absorption rate of laser light, to fly is equivalent to the energy required to cause transparent powder to fly.

2. The transparent powder flies even when the carrier is formed of a transparent resin film.

3. The transparent resin film forming the carrier is not degraded by being irradiated with pulsed laser light a plurality of times, up to 1000 times.

The distance between the carrier111and the object200is preferably approximately 3 times to 4 times greater than the average particle diameter of the modeling material201. In this manner, the contact between an upper-side particle and a lower-side particle before and after being flown can be avoided. Thus, the dispersion of the modeling material201due to flying can be avoided.

Further, the melting laser116functioning to heat the surface of the object200is disposed outside of the carrier111. As the melting laser116, a pulsed laser is not required to be actively used, and a continuous-wave laser is suitable.

The melting laser116heats and melts the surface of the object200to be fabricated on the stage101, such that the surface of the object200is in a melted state.

As described, the melting laser116heats and melts the surface of the object200, such that the surface of the object200is in a melted state. However, as long as the surface of the object200is melted by the energy of one or more energy sources, convection, a lamp, inductive heating, dielectric heating, and the like may be applied instead of laser heating. Further, the “surface” may include one layer that is formed at once, or may include a plurality of layers such as two or three layers. Alternatively, the “surface” may include a part of or the entirety of each layer. That is, it is important for the “surface” to include a part of the outermost layer.

InFIG.1, laser light116a, emitted from the melting laser116, is directed at the irradiation position of the pulsed laser light115a(the landing position of the modeling material201). The irradiation positions of the laser light116aand the pulsed laser light115acan be adjusted, and may be changed in accordance with the type of the material and the fabrication speed.

Accordingly, the modeling material201, caused to fly by the irradiation of the laser light116a, lands on the surface of the object200melted by the laser light116aemitted from the melting laser116. As a result, the modeling material201adheres to the object200.

The relationship between the timing at which the modeling material201flies and the timing at which the object200starts to be melted is not particularly limited. That is, the surface of the object200may be melted before the modeling material201flies. Alternatively, the surface of the object200may be melted after the modeling material201flies. Further, after the modeling material201flies, the surface of the object200may be melted, and the modeling material201may land on the melted surface of the object200.

Variations in landing positions and inappropriate landing positions can be adjusted for each layer. The shape of an object is not determined by the flying laser115and is determined by the melting laser116.

Further, the carrier111includes the cleaning blade117that removes the modeling material201remaining on the carrier111. The cleaning blade117is disposed on the downstream side in the rotational direction of the carrier111. The modeling material201removed by the cleaning blade117is collected in the collecting case118.

Next, effects of the three-dimensional modeling apparatus100will be described with reference to a flowchart ofFIG.2.

When the three-dimensional modeling apparatus100starts a fabrication process, the supply device112grinds and rubs a modeling material201stored in the supply device112with the blade122(step S1, hereinafter simply referred to as “S1”). The modeling material201is conveyed by the knurling roller123(S2), and the modeling material201is supplied onto the peripheral surface of the carrier111such that portions of the modeling material201do not overlap (S3). The supply device112continues to supply the modeling material201onto the carrier111until the fabrication is completed.

In this manner, the supply device112supplies the modeling material201onto the peripheral surface of the carrier111. The modeling material201is carried on the surface of the carrier111disposed above the stage101that supports an object200.

The modeling material201is conveyed to a position above the stage101by the rotation of the carrier111, and a ceiling of the modeling material201is formed above the stage101.

In the meantime, at a timing at which the fabrication is started (S5), the melting laser116emits the laser light116ato heat and melt a part of the surface of the object200to which the modeling material201adheres (S6). Note that a first layer forming the object200is fused because of the temperature of the stage heater102.

The flying laser115irradiates the modeling material201with the pulsed laser light115abased on fabrication data, thereby causing the modeling material201carried by the carrier111to fly from the carrier111to the melted part of the object200(S7).

The modeling material201flown from the carrier111lands on the melted part of the surface of the object200, and is integrated with the object200. That is, the object200is grown by an amount corresponding to the integrated modeling material.

Accordingly, while sequentially conveying the modeling material201by the continuous rotation of the carrier111to a position above the stage101, the three-dimensional modeling apparatus100repeats the fabrication process for causing the melting laser116to melt the surface of the object200, and causing the flying laser115to irradiate the modeling material201such that the modeling material201flies and lands on the object200, until the fabrication is completed (S8).

In this manner, a three-dimensional object can be fabricated by growing the object200to a desired shape.

The modeling material201, flown from the carrier111, lands on and adheres to the melted surface of the object200. Therefore, the modeling material201is not dispersed due to collision with the object200. Accordingly, even edges of the object200can be highly accurately formed, thus improving fabrication quality.

Further, the modeling material201is not limited to a crystalline resin, and a mixture of a crystalline resin and an amorphous resin can be used as the modeling material201. Therefore, a variety of materials can be utilized. Further, the fabrication speed can be increased by continuous fabrication, and waste materials can be reduced.

<Flying Direction of Modeling Material201>

Next, the flying direction of the modeling material201will be described with reference toFIGS.3A through3C.FIG.3Ais a diagram illustrating a deviation of the flying direction of a modeling material201adue to inertia,FIG.3Bis a diagram illustrating a variation in the flying directions of modeling materials201band201c, andFIG.3Cis a diagram illustrating an effect of reducing a variation in the flying directions of modeling materials201dand201eaccording to the first embodiment.

In each of the examples illustrated inFIGS.3A through3C, while the carrier111is circularly moving at a moving velocity V1, a modeling material carried by the carrier111is irradiated with the pulsed laser light115a, and the modeling material flies toward the surface of the object200. The direction indicated by an arrow30is the moving direction of the carrier111and is an example of a “predetermined direction”.

InFIG.3A, the modeling material201aflies towards the surface of the object200at an initial velocity V2in the direction of gravity g. At this time, the force of inertia of the moving carrier111acts on the modeling material201a. Thus, the modeling material201aflies at an initial velocity V3also in the moving direction indicated by the arrow30.

As a result of summing the initial velocities V2and V3, the modeling material201aflies in a direction indicated by an arrow31deviated from the direction of gravity g, which is a target direction of the modeling material201a. Note that a modeling material201a′ represents a modeling material that has flown in the direction indicated by the arrow31inFIG.3A.

For example, when it is assumed that the moving velocity V1of the modeling material201ais 100 (mm/s) and the flying time of the modeling material201is 0.02 (s), the modeling material201alands on the surface of the object200at a position deviated by “100·0.02=2 (mm)” in the moving direction with respect to the direction of gravity g.

Further, the flying time of the modeling material201may vary. Example factors of variations in flying time include variations in the initial velocity of modeling materials at the time of laser irradiation, variations in air resistance due to the difference in particle sizes of modeling materials, an effect caused by the collision of modeling materials, and an effect caused by the rotation of a modeling material.

In the upper part ofFIG.3B, an initial velocity V21indicates an initial velocity component of the modeling material201bin the direction of gravity g. As a result of summing the initial velocity V21in the direction of gravity g and the initial velocity V3in the moving direction, the modeling material201bflies in a direction indicated by an arrow311. In the lower part ofFIG.3B, an initial velocity V22indicates an initial velocity component of the modeling material201cin the direction of gravity g, and the initial velocity V22is greater than the above-described initial velocity V21. As a result of summing the initial velocity V22in the direction of gravity g and the initial velocity V3in the moving direction, the modeling material201cflies in a direction indicated by an arrow312. The direction indicated by the arrow312is close to the direction of gravity g as compared to the direction indicated by the arrow311.

As a result of the above-described variation in the flying directions of the modeling materials201band201c, the landing position of the modeling materials201band201con the surface of the object200would vary by a distance d. Such a variation would degrade the fabrication quality of the three-dimensional modeling apparatus100.

Conversely, in the present embodiment, as illustrated inFIG.3C, an external force F in a direction opposite to the moving direction of the carrier111is applied to flown modeling materials201dand201e. The external force F is caused by an electrostatic force generated by an electric field that is created by applying a voltage. The external force F is an example of a “predetermined external force”. However, the external force F is not necessarily caused by the electrostatic force, as long as the force can be applied uniformly to the flown modeling materials201dand201e. The external force F may be caused by the power of the airflow, magnetic force, gravity, or the like.

The external force F causes the flown modeling materials201dand201eto be moved in the direction opposite to the moving direction of the carrier111, thereby reducing a variation in the landing positions of the modeling materials201dand201eon the surface of the object200. In addition, the longer the flying time of a modeling material is, the greater the amount of movement of the modeling material by the external force F becomes. Further, the shorter the flying time of a modeling material is, the smaller the amount of movement of the modeling material by the external force F becomes. As a result, a variation in the landing positions of the modeling materials201dand201eon the surface of the object200can be reduced.

Next, a configuration of the fixing member155will be described with reference toFIG.4.FIG.4is a diagram illustrating an example configuration of the fixing member155.

As illustrated inFIG.4, the fixing member155is a member having a half-ring shape, and a slit portion155ais formed in a part of the fixing member155. In the three-dimensional modeling apparatus100, the fixing member155is disposed facing the object200with the carrier111being interposed between the fixing member155and the object200. The pulsed laser light115aof the flying laser11passes through the slit portion155aand is emitted to the carrier111.

The fixing member155is composed of a conductor such as stainless steel (SUS) metal, and is electrically conductive while ensuring wear resistance against contact with the carrier111that is stretched over the periphery of the fixing member155.

The slit portion155aof the fixing member155is composed of an insulator, such as glass, that is transparent to the pulsed laser light115a. The fixing member155is separated into one end portion155band the other end portion155cby the slit portion155acomposed of the insulator. Therefore, the one end portion155bis insulated from the other end portion155cwith the slit portion155abeing interposed therebetween.

Further, because the slit portion155ais transparent to the pulsed laser light115a, the pulsed laser light115acan pass through the slit portion155aand can be emitted to the modeling material201carried by the carrier111. The fixing member155is an example of an “external force applying member” configured to apply the external force F, and is also configured to support the carrier111.

Note that the slit portion155ais not necessarily composed of the insulator, and may be an opening. With this configuration, the pulsed laser light115acan pass through the slit portion155a, and the one end portion155bcan be insulated from the other end portion155c.

The one end portion155bis connected to a grounded portion156, and the other end portion155cof the fixing member155is electrically connected to a power supply157. When the flying laser115emits the pulsed laser light115a, the power supply157applies a voltage, thereby creating an electric field in the slit portion155a.

Typically, the modeling material201carries minute electric charges during the conveyance of the modeling material201. By utilizing the electric charges, an electrostatic force in the direction opposite to the moving direction of the carrier111can be applied to the modeling material201. This electrostatic force causes the flown modeling material201to be moved in the direction opposite to the moving direction of the carrier111, thereby reducing the variation in the landing position of the modeling material201.

Further, in the present embodiment, PA 12 is used as the modeling material201, and the modeling material201is positively charged. Accordingly, an electric field in the downstream direction is created on the surface of the carrier111by arranging the grounded portion156on the upstream side in the moving direction of the carrier111and the power supply157for applying a voltage on the downstream side. Therefore, the electrostatic force in the direction opposite to the moving direction of the carrier111can be applied to the modeling material201.

The modeling material201may be negatively charged depending on the type of the modeling material201. In such a case, the grounded portion156and the power supply157illustrated inFIG.4may be arranged reversely. Further, a switch or any other device may be utilized to switch the arrangement of the power supply157and the grounded portion156depending on the type of the modeling material201. In this manner, the external force F caused by the electrostatic force can be appropriately applied in accordance with the type of the modeling material201.

In the present embodiment, the modeling material201is not specifically charged in an active manner. However, the modeling material201may be triboelectrically charged in an active manner by mixing the modeling material201with another powder material and stirring the mixture, or by causing the modeling material201to pass through a nip between rotating members, as in the case of a toner for electrophotography. Accordingly, the external force F caused by the electrostatic force can be appropriately applied to the modeling material201.

<Conditions for Generating External Force F>

Next, more detailed conditions for generating the external force F will be described.

It is assumed that a modeling material201atakes time t (s) to land on the surface of the object200after flying, and a modeling material201btakes time t+Δt (s) to land on the surface of the object200after flying. When the moving velocity of the carrier111is assumed to be V1(m/s), a variation in the landing positions of the modeling material201aand the modeling material201bcan be expressed by the following formula (1).
V1(t+Δt)−V1(t)=V1·Δt(1)

When a voltage E (V) is assumed to be applied to the slit portion155ahaving a width w (m), an electric field is represented by E/w (N/C). Further, when the amount of electric charge per unit mass of the modeling material201is assumed to be Q (C/kg), the acceleration applied to the modeling material201is represented by E·Q/w (m/s2).

Accordingly, the correction amount of the variation in the landing positions of the modeling material201aand the modeling material201bcan be expressed by the following formula (2).
E·Q·(t+Δt)2/(2·w)−E·Q·t2/(2·w)=E·Q·t·Δt/w(2)

A voltage for correcting the variation in the landing positions is represented by V·Δt=E·Q·t·Δt/w, that is E=V1·w/(Q·t).

The following are examples of estimated values for generating the external force according to the present embodiment.

Amount of electric charge Q: 0.3 (mC/kg)

There may be cases where an error occurs in the above-described estimated values due to an electric field that is not uniformly formed in the horizontal direction, a variation in air resistance due to the difference in particle sizes of modeling materials, an effect caused by the rotation of a modeling material, or the like. Therefore, it is preferable to adjust the conditions for generating the external force in a range of approximately ±50% of the estimated values.

As described above, in the present embodiment, when the modeling material201carried by the carrier111is caused to fly to the surface of the object200, the external force F generated by an electric field is applied to the modeling material201. The external force F acts in the direction opposite to the moving direction of the carrier111. Further, the electric field is created by applying a voltage to the fixing member155.

By applying the external force F to the flown modeling material201, the modeling material201is moved in the direction opposite to the moving direction of the carrier111. Accordingly, variations in the landing position of the modeling material201on the surface of the object200can be reduced. Further, as the flying time of the modeling material201increases, the amount of movement of the modeling material201by the external force F increases. Further, as the flying time of the modeling material201decreases, the amount of movement of the modeling material201by the external force F decreases. As a result, variations in the landing position of the modeling material201can be reduced.

As described above, variations in the landing position of the modeling material201on the surface of the object200caused by inertia and variations in flying time can be reduced, thereby improving fabrication quality.

Further, in the present embodiment, the fixing member155functioning to support the carrier111is used to apply a voltage to the carrier111, thereby applying the external force F to the flown modeling material201. That is, the carrier111can also function to apply the external force F. Thus, the external force F can be applied to the flown modeling material201without any additional configuration for applying the external force F.

Second Embodiment

Next, a three-dimensional modeling apparatus100aaccording to a second embodiment will be described.FIG.5is a diagram illustrating an example configuration of an electrically conductive member160of the three-dimensional modeling apparatus100a. InFIG.5, an arrow30indicates the moving direction of the carrier111, and an arrow32indicates the scanning direction of the pulsed laser light115a.

As illustrated inFIG.5, the electrically conductive member160includes a wire160aand a wire160b, and is disposed in a space between the carrier111and the object200. The wire160aand the wire160b, constituting the electrically conductive member160, are spaced apart from each other in a direction along the moving direction of the carrier111, such that the pulsed laser light115apasses between the wire160aand the wire160b.

Each of the wires160aand160bis an elongated member that is made of highly electrically conductive metal such as nickel, and the long side of each of the wires160aand160bis in the scanning direction of the pulsed laser light115a.

Further, the wire160adisposed on the upstream side in the moving direction of the carrier111is electrically connected to a grounded portion161, and the wire160bdisposed on the downstream side is connected to a power supply162. The power supply162applies a voltage to the wire160a, thereby creating an electric field in the space between the wire160aand the wire160b. Accordingly, an electrostatic force generated by the electric field can be applied to the flown modeling material201as the external force F.

When the modeling material201carried by the carrier111is irradiated with the pulsed laser light115aand flies to the surface of the object200, the flown modeling material201is moved by the external force F in the direction opposite to the moving direction of the carrier111. Accordingly, variations in the landing position of the modeling material201on the surface of the object200can be reduced.

An electric field can be directly controlled by the electrically conductive member160including the wires160aand160bwithout the fixing member155. Therefore, variations in the landing position of the modeling material201can be more preferably reduced. A method for setting the voltage applied to the electrically conductive member160and the arrangement of the wires160aand160bare similar to those described in the first embodiment, and a duplicate description thereof will be omitted.

Third Embodiment

Next, a three-dimensional modeling apparatus100baccording to a third embodiment will be described. In the present embodiment, an external force is applied to a flown modeling material by supplying air to the flown modeling material. In this manner, variations in the landing position of the modeling material on the surface of the object can be reduced.

FIG.6is a diagram illustrating an example configuration of the three-dimensional modeling apparatus100b. As illustrated inFIG.6, the three-dimensional modeling apparatus100bincludes a fan170that is an example of an air blower.

The fan170is configured to be operated when the modeling material201is caused to fly, and to blow air to the flown modeling material201in the direction opposite to the moving direction of the carrier111. In this manner, the external force F is applied to the modeling material201by the power of the airflow. Accordingly, variations of the landing position of the modeling material201on the surface of the object can be reduced.

The speed of airflow from the fan170is preferably the same as or is in a range of ±50% of the moving velocity of the carrier111such that variations in the flying direction of the modeling material201can be eliminated. In the present embodiment, the speed of airflow is set to 0.1 (m/s) that is the same as the moving velocity of the carrier111.

When the external force F is applied by the electrostatic force generated by an electric field, there may be cases where the operation of the three-dimensional modeling apparatus may be affected by an electric discharge. However, in the present embodiment, because the external force F is caused by the power of the airflow, the three-dimensional modeling apparatus can fabricate a three-dimensional object without being affected by an electric discharge.

However, there may be cases where natural convection may affect the operation of the three-dimensional modeling apparatus. Therefore, it is preferable to take into account the state of airflow. In addition, in order to stabilize airflow, it is preferable to constantly generate ionic wind by a capacitor instead of the fan.

Fourth Embodiment

Next, a three-dimensional modeling apparatus100caccording to a fourth embodiment will be described. In the present embodiment, an electrostatic force is used to apply an external force to a modeling material that has flown. Accordingly, variations in the landing position of the modeling material on the surface of the object can be reduced. Further, the three-dimensional modeling apparatus100cincludes a supply device configured to stably supply the modeling material to a carrier. The supply device includes a conveyance carrier configured to carry and convey the modeling material stored in a material container, and a regulator configured to regulate the layer thickness of the modeling material carried by the conveyance carrier.

FIG.7is a diagram illustrating an example configuration of the three-dimensional modeling apparatus100c. As illustrated inFIG.7, the three-dimensional modeling apparatus100cincludes small-diameter rollers158and159, a slit103, and a supply device300.

The small-diameter rollers158and159are support members that support the carrier111by contacting the inner side of the carrier111. The carrier111is stretched over the small-diameter rollers158and159, and the small-diameter rollers158and159are driven to rotate in accordance with the circulation movement of the carrier111.

Instead of the fixing member155(seeFIG.1) according to the first embodiment, the small-diameter rollers158and159functioning as the support members that support the carrier111are provided. Accordingly, the carrier111can be circularly moved at high speed, and also an effect of preventing static electricity can be obtained.

Further, the small-diameter roller158is electrically connected to the grounded portion156(seeFIG.4), and the small-diameter roller159is connected to the power supply157(seeFIG.4). When the pulsed laser light115ais emitted from the flying laser115to the carrier111, the three-dimensional modeling apparatus100ccauses the power supply157to apply a voltage so as to create an electric field between the small-diameter roller158and the small-diameter roller159.

Typically, the modeling material201carries minute electric charges during the conveyance of the modeling material201. Therefore, an electrostatic force acting in a direction opposite to the moving direction of the carrier111can be applied to the modeling material201. This electrostatic force causes the flown modeling material201to be moved in the direction opposite to the moving direction of the carrier111, thereby reducing a landing position variation as indicated by d inFIG.3C.

The slit103is a member having an opening through which the laser light116aemitted from the melting laser116passes. In the three-dimensional modeling apparatus100c, the object200is irradiated with the laser light116athat has passed through the slit103.

By causing the melting laser116to pass through the slit103, the object200can be vertically irradiated with the laser light116awhile the heat dissipation of the object200is reduced. Further, it is preferable to provide an infrared camera having an optical system coaxial with the optical axis of the melting laser116. With the above-described infrared camera, the melting state and the temperature of the object200being irradiated with the laser light116acan be observed, and the fabrication can be controlled based on the observed conditions of the object200.

The supply device300includes a modeling material container320, a carrying roller301, a supplying roller303, a doctor roller310, and a scraper311. The supply device300is configured to supply the modeling material201to the carrier111.

The modeling material container320is a container that stores the modeling material201. The carrying roller301is an example of a conveyance carrier configured to carry, on the surface thereof, and convey the modeling material201stored in the modeling material container320.

The supplying roller303is rotatably provided in the modeling material container320, and is configured to rotate to supply the modeling material201to the carrying roller301. The doctor roller310is rotatably provided such that the surface of the doctor roller310is in proximity to the surface of the carrying roller301. The doctor roller310is configured to regulate the thickness of the modeling material201, carried on the surface of the carrying roller301, while rotating. The doctor roller310is an example of a regulator.

The scraper311is configured to clean the doctor roller310by scraping off the modeling material201remaining on the surface of the doctor roller310while contacting the surface of the doctor roller310.

In the three-dimensional modeling apparatus100c, the supply device300is disposed on the upstream side in the rotational direction of the carrying roller301. The supplying roller303supplies the modeling material201to the carrying roller301, and the doctor roller310regulates the thickness of the modeling material201on the surface of the carrying roller301. In this manner, the supply device300can continuously and stably form a thin layer of the modeling material201on the surface of the carrying roller301.

The carrying roller301contacts the carrier111and transfers the thin layer of the modeling material201onto the surface of the carrier111, thereby forming the thin layer of the modeling material201on the surface of the carrier111.

The thin layer of the modeling material201can firmly adhere to the surface of the carrier111when V111<V301is satisfied, where V111denotes the conveying speed of the carrier111and V301denotes the peripheral speed of the carrying roller301.

Further, the configuration and the arrangement of the supply device300can be changed in accordance with the type of the modeling material201stored and held in the modeling material container320. For example, the material or the outer diameter of each of the carrying roller301and the supplying roller303, the shape of the doctor roller310, or the contact pressure or the contact position of the doctor roller310with respect to the carrying roller301can be changed. The supply device300can preliminarily store the above-described information in an information storage unit such as an IC chip, and the supply device300can acquire and change the information by referring to the information storage unit as necessary.

Further, it is preferable to dispose a leveling blade on the upstream side of the supply device300. The leveling blade can make the modeling material201uniform in a pre-step before the modeling material201is supplied and make the amount of the modeling material201uniform after the modeling material201passes through the supply device300.

Further, although the embodiments of the present invention have been described in detail above, the present invention is not limited to the particulars of the above-described embodiments, and variations and modifications may be made to the above-described embodiments without departing from the scope of the present invention.

Further, a three-dimensional modeling method according to an embodiment of the present invention is also provided. For example, the three-dimensional modeling method includes carrying a modeling material by a carrier, causing the modeling material carried by the carrier to fly to a surface of an object, and applying a predetermined external force to the flown modeling material. Accordingly, an effect similar to that of the three-dimensional modeling apparatus can be obtained by the three-dimensional modeling method.

According to at least one embodiment, fabrication quality can be improved.