Patent Publication Number: US-2021162730-A1

Title: Method of manufacturing three-dimensionally formed object and three-dimensionally formed object manufacturing apparatus

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to a method of manufacturing a three-dimensionally formed object and a three-dimensionally formed object manufacturing apparatus. 
     2. Related Art 
     In the related art, various methods of manufacturing a three-dimensionally formed object have been disclosed. Among these, a method of forming a three-dimensionally formed object using a fluid composition is disclosed. 
     For example, JP-A-2008-184622 discloses a method of manufacturing a three-dimensionally formed object, the method including: forming a layer using a metal paste as a fluid composition; and manufacturing a three-dimensionally formed object while irradiating a region of the layer corresponding to the three-dimensionally formed object with laser light to sinter or melt the region. 
     However, in a case where the three-dimensionally formed object is manufactured while sintering or melting the layer corresponding to the three-dimensionally formed object, other regions of the layer excluding the region corresponding to the three-dimensionally formed object are sintered or melted due to heat generated during the sintering or melting of the region corresponding to the three-dimensionally formed object. Therefore, when an extracting operation of extracting the three-dimensionally formed object, a forming operation after the extracting operation, or the like is performed, the load may be high. That is, in the method of manufacturing a three-dimensionally formed object in the related art, the number of steps performed after a three-dimensionally formed object is manufactured is not sufficiently reduced. 
     SUMMARY 
     An advantage of some aspects of the invention is to reduce the number of steps performed after a three-dimensionally formed object is formed. 
     A first aspect of the invention is directed to a method of manufacturing a three-dimensionally formed object including: forming a layer using a fluid composition including constituent material particles of a three-dimensionally formed object and a fluid composition including support portion-forming particles for forming a support portion which supports the three-dimensionally formed object during the formation of the three-dimensionally formed object; and imparting energy to the constituent material particles and the support portion-forming particles, in which in the imparting of the energy, the energy is imparted such that a temperature of the constituent material particles and a temperature of the support portion-forming particles are equal to or higher than a melting point of the constituent material particles and are lower than a melting point of the support portion-forming particles. 
     According to this aspect, the energy is imparted such that the temperature of the constituent material particles and the temperature of the support portion-forming particles are equal to or higher than the melting point of the constituent material particles and are lower than the melting point of the support portion-forming particles. Therefore, the melting of the support portion can be prevented while melting the constituent material of the three-dimensionally formed object. Therefore, when an extracting operation of extracting the three-dimensionally formed object, a forming operation after the extracting operation, or the like is performed, an increase in load caused by the melting of other regions of the layer excluding the region corresponding to the three-dimensionally formed object can be prevented. Accordingly, the number of steps performed after a three-dimensionally formed object is formed can be reduced. 
     A second aspect of the invention is directed to the method of manufacturing a three-dimensionally formed object according to the first aspect, in which in the forming of the layer, the fluid composition including the constituent material particles and the fluid composition including the support portion-forming particles are ejected in the form of liquid drops to form the layer. 
     According to this aspect, the fluid composition including the constituent material particles and the fluid composition including the support portion-forming particles are ejected in the form of liquid drops to form the layer. Therefore, by forming the layer, the three-dimensionally formed object can be simply formed. 
     A third aspect of the invention is directed to the method of manufacturing a three-dimensionally formed object according to the first or second aspect, in which the method further includes repeating the forming of the layer. 
     According to this aspect, the method of manufacturing a three-dimensionally formed object includes repeating the forming of the layer. Therefore, by repeating the forming of the layer, the three-dimensionally formed object can be simply formed. 
     A fourth aspect of the invention is directed to the method of manufacturing a three-dimensionally formed object according to any one of the first to third aspects, in which in the imparting of the energy, the energy is imparted such that a temperature of the constituent material particles and a temperature of the support portion-forming particles are equal to or higher than a sintering temperature of the support portion-forming particles. 
     According to this aspect, the energy is imparted such that the temperature of the constituent material particles and the temperature of the support portion-forming particles are equal to or higher than the sintering temperature of the support portion-forming particles. That is, the constituent material particles are melted, and the support portion-forming particles are sintered. Since the sintering portion can be simply separated from the melting portion, the number of steps performed after a three-dimensionally formed object is formed can be reduced. 
     A fifth aspect of the invention is directed to the method of manufacturing a three-dimensionally formed object according to any one of the first to fourth aspects, in which the forming of the layer is adjusted such that a thickness of a layer including the constituent material particles and a thickness of a layer including the support portion-forming particles which corresponds to the layer match with each other after the imparting of the energy. 
     According to this aspect, the forming of the layer is adjusted such that a thickness of a layer including the constituent material particles and a thickness of a layer including the support portion-forming particles which corresponds to the layer match with each other after the imparting of the energy. Therefore, since there is no difference in the thickness between the support layer and the constituent layer, it is not necessary to adjust the thicknesses of the layers, and a high-precision three-dimensionally formed object can be manufactured. 
     A sixth aspect of the invention is directed to the method of manufacturing a three-dimensionally formed object according to any one of the first to fifth aspects, in which the imparting of the energy is performed after performing the forming of the layer once or multiple times to form one layer or plural layers. 
     According to this aspect, the imparting of the energy is performed after performing the forming of the layer once or multiple times to form one layer or plural layers. For example, by performing the imparting of the energy after performing the forming of the layer multiple times to form plural layers, the number of times of performing the constituent layer forming step can be reduced, and a three-dimensionally formed object can be rapidly manufactured. By performing the imparting of the energy once to form a layer, even in a case where one material is disposed to cover the other material on an inclined surface or the like, the two materials are exposed to the same surface in each of the layers, and thus energy can be appropriately imparted to each of the materials. 
     A seventh aspect of the invention is directed to the method of manufacturing a three-dimensionally formed object according to any one of the first to sixth aspects, in which in the imparting of the energy, the same intensity of energy is imparted to the constituent material particles and the support portion-forming particles. 
     According to this aspect, the same intensity of energy is imparted to the constituent material particles and the support portion-forming particles. Therefore, the imparting of the energy can be simply performed. 
     An eighth aspect of the invention is directed to the method of manufacturing a three-dimensionally formed object according to any one of the first to sixth aspects, in which in the imparting of the energy, different intensities of energy are imparted to the constituent material particles and the support portion-forming particles. 
     According to this aspect, different intensities of energy are imparted to the constituent material particles and the support portion-forming particles. Therefore, when an extracting operation of extracting the three-dimensionally formed object, a forming operation after the extracting operation, or the like is performed, an increase in load caused by the melting or excessive sintering of other regions of the layer excluding the region corresponding to the three-dimensionally formed object can be prevented. 
     A ninth aspect of the invention is directed to the method of manufacturing a three-dimensionally formed object according to any one of the first to eighth aspects, in which a porosity of a layer including the constituent material particles is adjusted to be lower than a porosity of a layer including the support portion-forming particles which corresponds to the layer after the imparting of the energy. 
     According to this aspect, a porosity of a layer including the constituent material particles is adjusted to be lower than a porosity of a layer including the support portion-forming particles which corresponds to the layer after the imparting of the energy. Therefore, when an extracting operation of extracting the three-dimensionally formed object, a forming operation after the extracting operation, or the like is performed, an increase in load caused by an excessively low porosity of the layer including the support portion-forming particles can be prevented. 
     A tenth aspect of the invention is directed to the method of manufacturing a three-dimensionally formed object according to any one of the first to ninth aspects, in which a porosity of a layer including the support portion-forming particle after the imparting of the energy is adjusted to be lower than that before the imparting of the energy. 
     According to this aspect, a porosity of a layer including the support portion-forming particle after the imparting of the energy is adjusted to be lower than that before the imparting of the energy. Therefore, the strength of the support portion is improved, and there is an advantageous effect in that, before an extracting operation of extracting a three-dimensionally formed object, the three-dimensionally formed object can be reliably held. 
     An eleventh aspect of the invention is directed to the method of manufacturing a three-dimensionally formed object according to any one of the first to tenth aspects, in which the constituent material particles include at least one component of aluminum, titanium, iron, copper, magnesium, stainless steel, or maraging steel, and the support portion-forming particles include at least one component of silica, alumina, titanium oxide, or zirconium oxide. 
     According to this aspect, in the imparting of the energy, the constituent material particles can be easily controlled to be melted, and the support portion-forming particles can be controlled to have a low sintered density. While securing the strength of the three-dimensionally formed object, an increase in the load of an extracting operation of extracting the three-dimensionally formed object, a forming operation after the extracting operation, or the like can be prevented. 
     A twelfth aspect of the invention is directed to a three-dimensionally formed object manufacturing apparatus including: an ejecting portion that ejects a fluid composition including constituent material particles of a three-dimensionally formed object; an ejecting portion that ejects a fluid composition including support portion-forming particles for forming a support portion which supports the three-dimensionally formed object during the formation of the three-dimensionally formed object; a control portion that controls the three-dimensionally formed object manufacturing apparatus to form a layer using the fluid composition including the constituent material particles and the fluid composition including the support portion-forming particles; and an energy imparting portion that imparts energy to the constituent material particles and the support portion-forming particles, in which the energy imparting portion is adjusted to impart the energy such that a temperature of the constituent material particles and a temperature of the support portion-forming particles are equal to or higher than a melting point of the constituent material particles and are lower than a melting point of the support portion-forming particles. 
     According to this aspect, the energy is imparted such that the temperature of the constituent material particles and the temperature of the support portion-forming particles are equal to or higher than the melting point of the constituent material particles and are lower than the melting point of the support portion-forming particles. Therefore, the melting of the support portion can be prevented while melting the constituent material of the three-dimensionally formed object. Therefore, when an extracting operation of extracting the three-dimensionally formed object, a forming operation after the extracting operation, or the like is performed, an increase in load caused by the melting of other regions of the layer excluding the region corresponding to the three-dimensionally formed object can be prevented. Accordingly, the number of steps performed after a three-dimensionally formed object is formed can be reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1A  is a diagram showing a schematic configuration of a three-dimensionally formed object manufacturing apparatus according to an embodiment of the invention, and  FIG. 1B  is an enlarged view showing a C portion shown in  FIG. 1A . 
         FIG. 2A  is a diagram showing a schematic configuration of the three-dimensionally formed object manufacturing apparatus according to the embodiment of the invention, and  FIG. 2B  is an enlarged view showing a C′ portion shown in  FIG. 2A . 
         FIG. 3  is a diagram showing the external appearance of a head base according to the embodiment of the invention when seen from a D direction shown in  FIG. 1B . 
         FIG. 4  is a cross-sectional view taken along line E-E′ shown in  FIG. 3 . 
         FIGS. 5A to 5C  are plan views schematically showing a relationship between a disposition of head units according to the embodiment of the invention and a formed state of landed portions. 
         FIGS. 6A and 6B  are plan views schematically showing a relationship between a disposition of head units according to the embodiment of the invention and a formed state of landed portions. 
         FIG. 7  is a plan view schematically showing a relationship between a disposition of head units according to the embodiment of the invention and a formed state of landed portions. 
         FIGS. 8A and 8B  are diagrams schematically showing other disposition examples of head units disposed on the head base. 
         FIGS. 9A to 9H  are diagrams schematically showing the process of manufacturing a three-dimensionally formed object according to an example of the invention. 
         FIG. 10  is a flowchart showing the method of manufacturing a three-dimensionally formed object according to the example of the invention. 
         FIGS. 11A to 11E  are diagrams schematically showing a process of manufacturing a three-dimensionally formed object according to an example of the invention. 
         FIG. 12  is a flowchart showing a method of manufacturing a three-dimensionally formed object according to an example of the invention. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, embodiments of the invention will be described with reference to the drawings. 
       FIGS. 1A to 2B  are diagrams showing a schematic configuration of a three-dimensionally formed object manufacturing apparatus according to an embodiment of the invention. 
     Here, the three-dimensionally formed object manufacturing apparatus according to the embodiment includes two kinds of material supply portions (head bases). However, in each of  FIGS. 1A to 2B , only one of the material supply portions is shown, and the other material supply portion is not shown. In addition, the material supply portion shown in  FIGS. 1A and 1B  supplies a fluid composition (constituent material) including constituent material particles of a three-dimensionally formed object. The material supply portion shown in  FIGS. 2A and 2B  supplies a fluid composition (support portion-forming material) including support portion-forming particles for forming a support portion which supports the three-dimensionally formed object during the formation of the three-dimensionally formed object. Each of the fluid composition including the constituent material particles and the fluid composition including the support portion-forming particles may or may not include a solvent and a binder. 
     “Three-dimensional forming” described in this specification represents forming a so-called three-dimensionally formed object which also includes a planar formed object, that is, a so-called two-dimensional formed object having a thickness. In addition, the meaning of “support” includes supporting something from below or side and, in some cases, also includes supporting something from above. 
     A three-dimensionally formed object manufacturing apparatus  2000  (hereinafter, referred to as “forming apparatus  2000 ”) shown in  FIGS. 1A to 2B  includes: a base  110 ; a stage  120  that is provided so as to move in X, Y, and Z directions shown in the drawing or to be driven in a rotating direction around a Z axis by a driving device  111  as a driving unit which is included in the base  110 . 
     As shown in  FIGS. 1A and 1B , the three-dimensionally formed object manufacturing apparatus  2000  includes a head base support portion  130 . The base  110  is fixed to one end portion of the head base support portion  130 . A head base  1100  in which plural head units  1400  are held is fixed to the other end portion of the head base support portion  130 , in which each of the head units  1400  includes a constituent material ejecting portion that ejects the constituent material. 
     In addition, as shown in  FIGS. 2A and 2B , the three-dimensionally formed object manufacturing apparatus  2000  includes a head base support portion  130 ′. The base  110  is fixed to one end portion of the head base support portion  130 ′. A head base  1100 ′ in which plural head units  1400 ′ are held is fixed to the other end portion of the head base support portion  130 ′, in which each of the head units  1400 ′ includes a support portion-forming material ejecting portion that ejects the support portion-forming material. 
     Here, the head base  1100  and the head base  1100 ′ are provided in parallel on an XY plane. 
     The constituent material ejecting portion  1230  and the support portion-forming material ejecting portion  1230 ′ have the same configuration, except that different materials (the constituent material and the support portion-forming material) are ejected. However, the invention is not limited to the above-described configuration. 
     In the process of forming a three-dimensionally formed object  500 , layers  501 ,  502 , and  503  are formed on the stage  120 . In addition, in a region facing the stage  120 , a heating portion  1700  is provided, and irradiation of heat energy thereof is controlled to be started or stopped by a heating portion controller  1710 , which is connected to a control unit  400  described below, such that the entire region of the stage  120  can be heated. 
     In order to form the three-dimensionally formed object  500 , heat energy is irradiated (energy is imparted) by the heating portion  1700 . In order to protect the three-dimensionally formed object  500  from heat generated from the stage  120 , the three-dimensionally formed object  500  may be formed on a sample plate  121  having heat resistance. As the sample plate  121 , for example, a ceramic plate is used. As a result, high heat resistance can be obtained, the reactivity between the sample plate and the constituent material of the three-dimensionally formed object to be melted is low, and the deterioration of the three-dimensionally formed object  500  can be prevented. In  FIGS. 1A and 2A , for convenience of description, a three-layer structure including the layers  501 ,  502 , and  503  is adopted. However, layers (in  FIGS. 1A and 2A , up to a layer  50   n ) may be formed until the three-dimensionally formed object  500  has a desired shape. 
     Here, each of the layers  501 ,  502 ,  503 , and  50   n  includes: a support layer  300  that is formed of the support portion-forming material ejected from the support portion-forming material ejecting portion  1230 ′; and a constituent layer  310  (corresponding to a constituent region of the three-dimensionally formed object  500 ) that is formed of the constituent material ejected from the constituent material ejecting portion  1230 . Once a single layer is formed using the constituent material ejected from the constituent material ejecting portion  1230  and the support portion-forming material ejected from the support portion-forming material ejecting portion  1230 ′, the layer can be melted by the heating portion  1700  irradiating the entire region of the layer with heat energy. Further, by forming plural pairs of the constituent layers  310  and the support layers  300 , the shape of a three-dimensionally formed object is completed. This three-dimensionally formed object can be melted in a thermostatic chamber (heating portion) which is provided separately from the forming apparatus  2000 . 
       FIG. 1B  is an enlarged view showing a C portion which is the head base  1100  shown in  FIG. 1A . As shown in  FIG. 1B , the head base  1100  holds the plural head units  1400 . Although described below in detail, one head unit  1400  is formed by the constituent material ejecting portion  1230 , which is included in a constituent material supply device  1200 , being held by a holding jig  1400   a.  The constituent material ejecting portion  1230  includes: an ejection nozzle  1230   a;  and an ejection driving portion  1230   b  that is controlled by a material supply controller  1500  to eject the constituent material through the ejection nozzle  1230   a.    
       FIG. 2B  is an enlarged view showing a C′ portion which is the head base  1100 ′ shown in  FIG. 2A . As shown in  FIG. 2B , the head base  1100 ′ holds the plural head units  1400 ′. One head unit  1400 ′ is formed by the support portion-forming material ejecting portion  1230 ′, which is included in a support portion-forming material supply device  1200 ′, being held by a holding jig  1400   a ′. The support portion-forming material ejecting portion  1230 ′ includes: an ejection nozzle  1230   a ′; and an ejection driving portion  1230   b ′ that is controlled by the material supply controller  1500  to eject the support portion-forming material through the ejection nozzle  1230   a′.    
     In the embodiment, the heating portion  1700  will be described as an energy irradiating portion which irradiates electromagnetic waves as heat energy. By using electromagnetic waves as the heat energy to be irradiated, a supply material as a target can be efficiently irradiated with energy, and a high-quality three-dimensionally formed object can be formed. In addition, for example, the intensity of irradiation energy (power, scanning rate) can be easily controlled according to, for example, the kinds of materials to be ejected, and a three-dimensionally formed object having a desired quality can be obtained. However, the invention is not limited to the above-described configuration, and the layers may be heated using another method. It is needless to say that the invention is not limited to the configuration in which the layers are melted by electromagnetic waves. 
     As shown in  FIGS. 1A and 1B , the constituent material ejecting portion  1230  is connected to a constituent material supply unit  1210  through a supply tube  1220 , the constituent material supply unit  1210  accommodating the constituent material and corresponding to each of the head units  1400  which are held in the head base  1100 . A predetermined constituent material is supplied from the constituent material supply unit  1210  to the constituent material ejecting portion  1230 . The constituent material supply unit  1210  includes constituent material accommodating portions  1210   a,  and a supply material including raw materials of the three-dimensionally formed object  500  (a paste-like constituent material including metal particles (constituent material particles)), which is formed using the forming apparatus  2000  according to the embodiment, is accommodated in the constituent material accommodating portions  1210   a.  Each of the constituent material accommodating portions  1210   a  is connected to each of the constituent material ejecting portions  1230  through the supply tube  1220 . In this way, by including each of the constituent material accommodating portions  1210   a,  the constituent material supply unit  1210  can supply different kinds of materials through the head base  1100 . 
     As shown in  FIGS. 2A and 2B , the support portion-forming material ejecting portion  1230 ′ is connected to a support portion-forming material supply unit  1210 ′ through a supply tube  1220 ′, the support portion-forming material supply unit  1210 ′ accommodating the support portion-forming material and corresponding to each of the head units  1400 ′ which are held in the head base  1100 ′. A predetermined support portion-forming material is supplied from the support portion-forming material supply unit  1210 ′ to the support portion-forming material ejecting portion  1230 ′. The support portion-forming material supply unit  1210 ′ includes support portion-forming material accommodating portions  1210   a ′, and a supply material including the support portion-forming material which forms the support portion during the formation of the three-dimensionally formed object  500  (a paste-like support portion-forming material including ceramic particles (support portion-forming particles)) is accommodated in the support portion-forming material accommodating portions  1210   a ′. Each of the support portion-forming material accommodating portions  1210   a ′ is connected to each of the support portion-forming material ejecting portions  1230 ′ through the supply tube  1220 ′. In this way, by including each of the support portion-forming material accommodating portions  1210   a ′, the support portion-forming material supply unit  1210 ′ can supply different kinds of support portion-forming materials through the head base  1100 ′. 
     As the constituent material, for example, a slurry-like (or paste-like) mixed material including a single powder or a mixed powder, a solvent, and a binder can be used, in which examples of the single powder include powders of magnesium (Mg), iron (Fe), cobalt (Co), chromium (Cr), aluminum (Al), titanium (Ti), copper (Cu), and nickel (Ni), and examples of the mixed powder include powders of alloys including one or more of the above-described metals (maraging steel, stainless steel, cobalt-chromium-molybdenum, titanium alloys, nickel alloys, aluminum alloys, cobalt alloys, and cobalt-chromium alloys). 
     In addition, a general engineering plastic such as polyamide, polyacetal, polycarbonate, modified polyphenyl ether, polybutylene terephthalate, or polyethylene terephthalate can be used. Further, an engineering plastic such as polysulfone, polyether sulfone, polyphenylene sulfide, polyarylate, polyimide, polyamide imide, polyether imide, or polyether ether ketone can be used. 
     In this way, as the constituent material, for example, a metal other than the above-described metals, a ceramic, or a resin can be used without any particular limitation. 
     Examples of the solvent include: water; (poly) alkylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, or propylene glycol monoethyl ether; acetates such as ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, or isobutyl acetate; aromatic hydrocarbons such as benzene, toluene, or xylene; ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, ethyl-n-butyl ketone, diisopropyl ketone, or acetyl acetone; alcohols such as ethanol, propanol, or butanol; tetraalkylammonium acetates; sulfoxide solvents such as dimethyl sulfoxide or diethyl sulfoxide; pyridine solvents such as pyridine, γ-picoline, or 2,6-lutidine; and ionic liquids of tetraalkylammonium acetates (for example, tetrabutylammonium acetate). One kind or a combination of two or more kinds selected from the above examples can be used. 
     Examples of the binder include: synthetic resins such as an acrylic resin, an epoxy resin, a silicone resin, or a cellulose resin; and thermoplastic resins such as polylactic acid (PLA), polyamide (PA), or polyphenylene sulfide (PPS). 
     In the embodiment, the support portion-forming material includes a ceramic. As the support portion-forming material, for example, a slurry-like (or paste-like) mixed material can be used, the mixed material including a mixed powder of a metal oxide, a metal alkoxide, a metal, and the like, a solvent, and a binder. 
     However, the support portion-forming material is not particularly limited, and a metal or a resin other than ceramics described in the above-described examples of constituent material can be used. 
     The forming apparatus  2000  includes a control unit  400  which controls the stage  120 , the constituent material ejecting portions  1230  included in the constituent material supply device  1200 , the heating portion  1700 , and the support portion-forming material ejecting portions  1230 ′ included in the support portion-forming material supply device  1200 ′ based on data for forming a three-dimensionally formed object which is output from a data output device (not shown) such as a personal computer. The control unit  400  includes a control portion (not shown) which controls the stage  120  and the constituent material ejecting portion  1230  to be driven and operate in cooperation with each other and controls the stage  120  and the support portion-forming material supply device  1200 ′ to be driven and operate in cooperation with each other. 
     Regarding the stage  120  which is provided to be movable on the base  110 , based on control signals output from the control unit  400 , signals for controlling, for example, the moving start and stop, a moving direction, a moving amount, and a moving speed of the stage  120  are generated by a stage controller  410 , and the stage  120  is transported to the driving device  111  included in the base  110  and moves in the X, Y, and Z directions shown in the drawings. Regarding the constituent material ejecting portions  1230  included in the head units  1400 , based on control signals output from the control unit  400 , signals for controlling, for example, the amount of the material ejected through the ejection nozzles  1230   a  by the ejection driving portions  1230   b  included in the constituent material ejecting portions  1230  are generated by the material supply controller  1500 , and a predetermined amount of the constituent material is ejected through the ejection nozzles  1230   a  based on the generated signals. 
     Likewise, regarding the support portion-forming material ejecting portions  1230 ′ included in the head units  1400 ′, based on control signals output from the control unit  400 , signals for controlling, for example, the amount of the material ejected through the ejection nozzles  1230   a ′ by the ejection driving portions  1230   b ′ included in the support portion-forming material ejecting portions  1230 ′ are generated by the material supply controller  1500 , and a predetermined amount of the support portion-forming material is ejected through the ejection nozzles  1230   a ′ based on the generated signals. 
     Regarding the heating portion  1700 , a control signal is output from the control unit  400  to the heating portion controller  1710 , and an output signal for irradiating electromagnetic waves is output from the heating portion controller  1710  to the heating portion  1700 . 
     Next, the head units  1400  will be described in more detail. The head unit  1400 ′ has the same configuration as that of the head unit  1400 , except that the support portion-forming material ejecting portions  1230 ′ are disposed in the same configuration instead of the constituent material ejecting portions  1230 . Therefore, the detailed configuration of the head unit  1400 ′ will be omitted. 
       FIGS. 3 and 4  show examples of a state where the head units  1400  are held in the head base  1100  and a state where the constituent material ejecting portions  1230  are held in each of the head units  1400 .  FIG. 3  is a diagram showing the external appearance of the head base  1100  when seen from a direction D shown in  FIG. 1B .  FIG. 4  is a schematic cross-sectional view taken along line E-E′ shown in  FIG. 3 . 
     As shown in  FIG. 3 , in the head base  1100 , the plural head units  1400  are held by a fixing unit (not shown). The head base  1100  of the forming apparatus  2000  according to the embodiment includes eight head units  1400  including, from below in the drawing, head units  1401  and  1402  on a first line, head units  1403  and  1404  on a second line, head units  1405  and  1406  on a third line, and head units  1407  and  1408  on a fourth line. Although not shown in the drawing, the constituent material ejecting portions  1230  included in each of the head units  1401  to  1408  are connected to the constituent material supply unit  1210  through the ejection driving portions  1230   b  and the supply tubes  1220  and are held by the holding jigs  1400   a.    
     As shown in  FIG. 4 , the constituent material ejecting portions  1230  eject a material M, which is the constituent material of the three-dimensionally formed object, to the sample plate  121 , which is mounted on the stage  120 , through the ejection nozzles  1230   a.  The head unit  1401  ejects the material M, for example, in the form of liquid drops, and the head unit  1402  ejects the material M, for example, in the form of a continuous body. In the forming apparatus  2000  according to the embodiment, the material M is ejected in the form of liquid drops. However, the ejection nozzles  1230   a  can supply the constituent material in the form of a continuous body. 
     The material M ejected through the ejection nozzles  1230   a  in the form of liquid drops flies substantially in the gravity direction and lands on the sample plate  121 . The landed material M forms landed portions  50 . An aggregate of the landed portions  50  is formed as the constituent layer  310  (refer to  FIGS. 1A and 1B ) of the three-dimensionally formed object  500  formed on the sample plate  121 . 
       FIGS. 5A to 7  are plan views (when seen from the D direction shown in  FIGS. 1A and 1B ) schematically showing a relationship between a disposition of the head units  1400  and a formed state of the landed portions  50 . First, as shown in  FIG. 5A , at a forming start point q 1  on the sample plate  121 , the material M is ejected through the ejection nozzles  1230   a  of the head units  1401  and  1402  and lands on the sample plate  121  to form landed portions  50   a  and  50   b.  For convenience of description, the landed portions  50  are hatched in a plan view, and the constituent layer  310  of the first layer  501  formed on the top surface of the sample plate  121  will be described as an example. 
     First, as shown in  FIG. 5A , at the forming start point q 1  of the constituent layer  310  of the layer  501  on the sample plate  121 , the material M is ejected through the constituent material ejecting portions  1230  included in the head units  1401  and  1402  on the first line from below in the drawing. The ejected material M forms the landed portions  50   a  and  50   b.    
     While continuously ejecting the material M through the constituent material ejecting portions  1230  of the head units  1401  and  1402 , the sample plate  121  is moved in the Y (+) direction relative to the head base  1100  such that the forming start point q 1  shown in  FIG. 5B  is positioned at a position corresponding to the head units  1403  and  1404  on the second line. As a result, the landed portions  50   a  and  50   b  extend while maintaining a width t ranging from the forming start point q 1  to a position q 2  after the relative movement of the sample plate  121 . Further, the material M is ejected from the head units  1403  and  1404  on the second line corresponding to the forming start point q 1  and starts to form landed portions  50   c  and  50   d.    
     As shown in  FIG. 5B , the landed portions  50   c  and  50   d  are started to be formed, and while continuously ejecting the material M through the constituent material ejecting portions  1230  of the head units  1403  and  1404 , the sample plate  121  is moved in the Y (+) direction relative to the head base  1100  such that the forming start point q 1  shown in  FIG. 5C  is positioned at a position corresponding to the head units  1405  and  1406  on the third line. As a result, the landed portions  50   c  and  50   d  extend while maintaining the width t ranging from the forming start point q 1  to the position q 2  after the relative movement of the sample plate  121 . Concurrently, the landed portions  50   a  and  50   b  extend while maintaining the width t ranging from the forming start point q 1  to a position q 3  after the relative movement of the sample plate  121 . The material M is ejected from the head units  1405  and  1406  on the third line corresponding to the forming start point q 1  and starts to form landed portions  50   e  and  50   f.    
     As shown in  FIG. 5C , the landed portions  50   e  and  50   f  are started to be formed, and while continuously ejecting the material M through the constituent material ejecting portions  1230  of the head units  1405  and  1406 , the sample plate  121  is moved in the Y (+) direction relative to the head base  1100  such that the forming start point q 1  shown in  FIG. 6A  is positioned at a position corresponding to the head units  1407  and  1408  on the fourth line. As a result, the landed portions  50   e  and  50   f  extend while maintaining the width t ranging from the forming start point q 1  to the position q 2  after the relative movement of the sample plate  121 . Concurrently, the landed portions  50   a  and  50   b  extend while maintaining the width t ranging from the forming start point q 1  to a position q 4  after the relative movement of the sample plate  121 , and the landed portions  50   c  and  50   d  extend while maintaining the width t ranging from the forming start point q 1  to the position q 3  after the relative movement of the sample plate  121 . The material M is ejected from the head units  1407  and  1408  on the fourth line corresponding to the forming start point q 1  and starts to form landed portions  50   g  and  50   h.    
     In a case where a position q 5  is set as a forming end point (hereinafter, the position q 5  will be referred to as “forming end point q 5 ”), as shown in  FIG. 6B , the sample plate  121  is relatively moved until the head units  1401  and  1402  reach the forming end point q 5  such that the landed portions  50   g  and  50   h  extend. In the head units  1401  and  1402  which have reached the forming end point q 5 , the ejection of the material M through the constituent material ejecting portions  1230  of the head units  1401  and  1402  is stopped. Further, while relatively moving the sample plate  121  in the Y (+) direction, the material M is ejected through the constituent material ejecting portions  1230  until the head units  1403 ,  1404 ,  1405 ,  1406 ,  1407 , and  1408  reach the forming end point q 5 . As a result, as shown in  FIG. 7 , the landed portions  50   a,    50   b,    50   c,    50   d,    50   e,    50   f,    50   g,  and  50   h  are formed in the region from the forming start point q 1  to the forming endpoint q 5  while maintaining the width t. In this way, while moving the sample plate  121  from the forming start point q 1  to the forming end point q 5 , the material M is ejected and supplied from the head units  1401 ,  1402 ,  1403 ,  1404 ,  1405 ,  1406 ,  1407 , and  1408  in this order. As a result, in this embodiment, a substantially rectangular aggregate of the landed portions  50  having a width T and a length J can be formed. In this way, the constituent layer  310  of the first layer  501  which is the aggregate of the landed portions  50  can be formed. 
     As described above, in the forming apparatus  2000  according to the embodiment, in synchronization with the movement of the stage  120  including the sample plate  121 , the materials M is selectively ejected and supplied through the constituent material ejecting portions  1230  included in the head units  1401 ,  1402 ,  1403 ,  1404 ,  1405 ,  1406 ,  1407 , and  1408 . As a result, the constituent layer  310  having a desired shape can be formed on the sample plate  121 . In addition, as described above, in this example, by simply moving the stage  120  in a single direction along the Y axis direction, the landed portions  50  having a desired shape can be formed in the region having the width T and the length J shown in  FIG. 7 , and further the constituent layer  310  which is the aggregate of the landed portions  50  can be formed therein. 
     In addition, regarding the material M ejected through the constituent material ejecting portions  1230 , a constituent material ejected and supplied from one unit or two or more units among the head units  1401 ,  1402 ,  1403 ,  1404 ,  1405 ,  1406 ,  1407 , and  1408  may be different from a constituent material ejected and supplied from the other units. Accordingly, by using the forming apparatus  2000  according to the embodiment, a three-dimensionally formed object formed of different materials can be formed. 
     In the first layer  501 , as described above, the support layer  300  can be formed using the same method as described above by ejecting the support portion-forming material through the support portion-forming material ejecting portions  1230 ′ before or after the formation of the constituent layer  310 . When the layers  502 ,  503 , . . . , and  50   n  are formed by being laminated on the layer  501 , the constituent layers  310  and the support layers  300  can be formed using the same method as described above. 
     The numbers and dispositions of the head units  1400  and the  1400 ′ included in the forming apparatus  2000  according to the embodiment are not limited to the above-described numbers and dispositions.  FIGS. 8A and 8B  are diagrams schematically showing other disposition examples of the head units  1400  disposed on the head base  1100 . 
       FIG. 8A  shows a state where the plural head units  1400  are provided in parallel in the X axis direction in the head base  1100 .  FIG. 8B  shows a state where the plural head units  1400  are provided in a lattice shape in the head base  1100 . The number of head units disposed is not limited to that of each of the examples shown in  FIGS. 8A and 8B . 
     Next, an example in which a method of manufacturing a three-dimensionally formed object is performed using the forming apparatus  2000  according to the embodiment will be described. 
       FIGS. 9A to 9H  are diagrams schematically showing an example of a process of manufacturing a three-dimensionally formed object which is performed using the forming apparatus  2000 . In the method of manufacturing a three-dimensionally formed object according to the example, whenever a single layer is formed by ejecting the constituent material and the support portion-forming material through the constituent material ejecting portions  1230  and the support portion-forming material ejecting portions  1230 ′, the layer is heated using the heating portion  1700  included in the forming apparatus  2000 . In addition, in the method of manufacturing a three-dimensionally formed object according to the example, a molten three-dimensionally formed object is manufactured. 
     In  FIGS. 9A to 9H , plural auxiliary lines are drawn in the Z direction such that the thicknesses of the support layer  300  and the constituent layer  310  can be easily recognized. 
     First, as shown in  FIG. 9A , the constituent layer  310  and the support layer  300  are formed in the first layer  501  by ejecting the constituent material through the constituent material ejecting portions  1230  and ejecting the support portion-forming material through the support portion-forming material ejecting portions  1230 ′. Here, the support layer  300  is formed in regions of the layer excluding a region where the three-dimensionally formed object is formed (a region corresponding to the constituent layer  310 ). 
     Next, as shown in  FIG. 9B , the first layer  501  is heated by the heating portion  1700  such that the constituent layer  310  is melted and the support layer  300  is sintered in the layer  501 . In the example, the heating temperature of the heating portion  1700  is set as a temperature (the melting point or higher) at which metal particles (constituent material particles) included in the constituent material are melted and a temperature (lower than the melting point) at which ceramic particles (support portion-forming particles) included in the support portion-forming material are sintered. 
     Hereinafter, the operation shown in  FIG. 9A  and the operation shown in  FIG. 9B  are repeated, thereby completing a three-dimensionally formed object. 
     Specifically, as shown in  FIG. 9C , the constituent layer  310  and the support layer  300  are formed in the second layer  502  by ejecting the constituent material through the constituent material ejecting portions  1230  and ejecting the support portion-forming material through the support portion-forming material ejecting portions  1230 ′. As shown in  FIG. 9D , the second layer  502  is heated by the heating portion  1700 . 
     Further, as shown in  FIG. 9E , the constituent layer  310  and the support layer  300  are formed in the third layer  503 . As shown in  FIG. 9F , the third layer  503  is heated by the heating portion  1700 . As shown in  FIG. 9G , the constituent layer  310  and the support layer  300  are formed in the fourth layer  504 . As shown in  FIG. 9H , the fourth layer  504  is heated by the heating portion  1700 . As a result, a three-dimensionally formed object (molten constituent layer  310 ) is completed. 
     Next, the method of manufacturing a three-dimensionally formed object according to the example shown in  FIGS. 9A to 9H  will be described using a flowchart. 
     Here,  FIG. 10  is the flowchart showing the method of manufacturing a three-dimensionally formed object. 
     As shown in  FIG. 10 , in the method of manufacturing a three-dimensionally formed object according to the example, firstly, data of a three-dimensionally formed object is acquired in Step S 110 . Specifically, for example, data representing the shape of the three-dimensionally formed object is acquired from, for example, an application program which is performed by a personal computer. 
     Next, in Step S 120 , data for each layer is created. Specifically, in the data representing the shape of the three-dimensionally formed object, bitmap data (cross-sectional data) is generated for each of cross-sections which are obtained by slicing the three-dimensionally formed object according to a forming resolution in the Z direction. 
     At this time, in the generated bitmap data, a region where the three-dimensionally formed object is formed is distinguished from regions where the three-dimensionally formed object is not formed. 
     Next, in Step S 130 , the constituent material is ejected (supplied) through the constituent material ejecting portions  1230  based on the data for forming the region where the three-dimensionally formed object is formed. As a result, the constituent layer  310  is formed. 
     Next, in Step S 140 , the support portion-forming material is ejected (supplied) through the support portion-forming material ejecting portions  1230 ′ based on the data for forming the regions where the three-dimensionally formed object is not formed. As a result, the support layer  300  is formed on the same layer as that on which the constituent layer  310  is formed in Step S 130 . 
     The order of performing Step S 130  and Step S 140  may be reversed, or Step S 130  and Step S 140  may be performed at the same time. 
     Next, in Step S 150 , the layer on which the constituent layer  310  is formed in Step S 130  and on which the support layer  300  is formed in Step S 140  is irradiated (imparted with heat energy) with electromagnetic waves by the heating portion  1700 . As a result, in this layer, the constituent layer  310  is melted, and the support layer  300  is sintered. 
     In this step, the constituent layer  310  is melted, and the support layer  300  is sintered. However, the support layer  300  is not necessarily sintered. 
     In Step S 160 , whether or not the formation of the three-dimensionally formed object is finished is determined based on the bitmap data corresponding to each of the layers which are generated in Step S 120 , and Steps S 130  to S 160  are repeated until the formation of the three-dimensionally formed object is finished. 
     Once the formation of the three-dimensionally formed object is finished, in Step S 170 , the three-dimensionally formed object is extracted (the regions corresponding to the support layer  300 , which are the regions where the three-dimensionally formed object is not formed, are removed from the layer to obtain the region corresponding to the constituent layer  310  which is the region where the three-dimensionally formed object is formed; that is, the three-dimensionally formed object is cleaned). As a result, the method of manufacturing a three-dimensionally formed object according to the example ends. 
     Next, another example in which a method of manufacturing a three-dimensionally formed object is performed using the forming apparatus  2000  according to the embodiment will be described. 
       FIGS. 11A to 11E  are diagrams schematically showing another example of a process of manufacturing a three-dimensionally formed object which is performed using the forming apparatus  2000 . In the method of manufacturing a three-dimensionally formed object according to the example, after the formation of a shape of a three-dimensionally formed object is finished by ejecting the constituent material and the support portion-forming material through the constituent material ejecting portions  1230  and the support portion-forming material ejecting portions  1230 ′, the shaped product of the three-dimensionally formed object is heated in a thermostatic chamber (heating portion) (not shown), which is provided separately from the forming apparatus  2000 , without using the heating portion  1700  included in the forming apparatus  2000 . In addition, in the method of manufacturing a three-dimensionally formed object according to the example, a molten three-dimensionally formed object is manufactured. 
     In  FIGS. 11A to 11E , plural auxiliary lines are drawn in the Z direction such that the thicknesses of the support layer  300  and the constituent layer  310  can be easily recognized. 
     First, as shown in  FIG. 11A , the constituent layer  310  and the support layer  300  are formed in the first layer  501  by ejecting the constituent material through the constituent material ejecting portions  1230  and ejecting the support portion-forming material through the support portion-forming material ejecting portions  1230 ′. Here, the support layer  300  is formed in regions of the layer excluding a region where the three-dimensionally formed object is formed (a region corresponding to the constituent layer  310 ). 
     Next, as shown in  FIG. 11B , the constituent layer  310  and the support layer  300  are formed in the second layer  502  by ejecting the constituent material through the constituent material ejecting portions  1230  and ejecting the support portion-forming material through the support portion-forming material ejecting portions  1230 ′. 
     As shown in  FIGS. 11C and 11D , the operations shown in  FIGS. 11A and 11B  are repeated, thereby completing the shape of the three-dimensionally formed object. 
     As shown in  FIG. 11E , the shaped product of the three-dimensionally formed object is heated in the thermostatic chamber (not shown) such that the constituent layer  310  is melted and the support layer  300  is sintered in the shaped product of the three-dimensionally formed object. As a result, a three-dimensionally formed object (molten constituent layer  310 ) is completed. In the example, the heating temperature in the thermostatic chamber is set as a temperature (the melting point or higher) at which metal particles (constituent material particles) included in the constituent material are melted and a temperature (lower than the melting point) at which ceramic particles (support portion-forming particles) included in the support portion-forming material are sintered. 
     Next, the method of manufacturing a three-dimensionally formed object according to the example shown in  FIGS. 11A to 11E  will be described using a flowchart. 
     Here,  FIG. 12  is the flowchart showing the method of manufacturing a three-dimensionally formed object. 
     Since operations in Steps S 110  to S 140  and Step S 170  of  FIG. 12  are the same as those in Steps S 110  to S 140  and Step S 170  of  FIG. 10 , the description thereof will not be repeated. 
     As shown in  FIG. 12 , in the method of manufacturing a three-dimensionally formed object according to the example, the process proceeds to Step S 160  after the completion of Step S 140 . 
     In Step S 160 , whether or not the formation of the shaped product of the three-dimensionally formed object is finished is determined based on the bitmap data corresponding to each of the layers which are generated in Step S 120 , and Steps S 130  to S 160  are repeated until the formation of the shaped product of the three-dimensionally formed object is finished. Once the formation of the shaped product of the three-dimensionally formed object is finished, the process proceeds to Step S 165 . 
     In Step S 165 , the shaped product of the three-dimensionally formed object, which is formed by repeating the Steps S 130  to S 160 , is heated in the thermostatic chamber (not shown) such that the constituent layer  310  is melted and the support layer  300  is sintered. In this step, the constituent layer  310  is melted, and the support layer  300  is sintered. However, the support layer  300  is not necessarily sintered. After the completion of Step S 165 , Step S 170  is performed. As a result, the method of manufacturing a three-dimensionally formed object according to the example ends. 
     As can be seen from the above two examples, the method of manufacturing a three-dimensionally formed object according to any one of the examples includes: a layer forming step (Steps S 130  and S 140 ) of forming a layer using a fluid composition (constituent material) including constituent material particles of a three-dimensionally formed object and a fluid composition (support portion-forming material) including support portion-forming particles for forming a support portion which supports the three-dimensionally formed object during the formation of the three-dimensionally formed object; and an energy imparting step (Steps S 150  and Steps S 165 ) of imparting energy to the constituent material particles and the support portion-forming particles. In the energy imparting step, the energy is imparted such that a temperature of the constituent material particles and a temperature of the support portion-forming particles are equal to or higher than a melting point of the constituent material particles and are lower than a melting point of the support portion-forming particles. 
     Therefore, the melting of the support portion can be prevented while melting the constituent material of the three-dimensionally formed object. When an extracting operation of extracting the three-dimensionally formed object, a forming operation after the extracting operation, or the like is performed, an increase in load caused by the melting of other regions of the layer excluding the region corresponding to the three-dimensionally formed object can be prevented. Accordingly, the number of steps performed after a three-dimensionally formed object is formed can be reduced. 
     In other words, the three-dimensionally formed object manufacturing apparatus (forming apparatus  2000 ) according to any one of the examples includes: an ejecting portion (constituent material ejecting portion  1230 ) that ejects a fluid composition (constituent material) including constituent material particles of a three-dimensionally formed object; an ejecting portion (support portion-forming material ejecting portion  1230 ′) that ejects a fluid composition (support portion-forming material) including support portion-forming particles for forming a support portion which supports the three-dimensionally formed object during the formation of the three-dimensionally formed object; a control portion (control unit  400 ) that controls the three-dimensionally formed object manufacturing apparatus to form a layer using the fluid composition including the constituent material particles and the fluid composition including the support portion-forming particles; and an energy imparting portion (heating portion  1700 ) that imparts energy to the constituent material particles and the support portion-forming particles. The energy imparting portion is adjusted to impart the energy such that a temperature of the constituent material particles and a temperature of the support portion-forming particles are equal to or higher than a melting point of the constituent material particles and are lower than a melting point of the support portion-forming particles. 
     Therefore, the melting of the support portion can be prevented while melting the constituent material of the three-dimensionally formed object. When an extracting operation of extracting the three-dimensionally formed object, a forming operation after the extracting operation, or the like is performed, an increase in load caused by the melting of other regions of the layer excluding the region corresponding to the three-dimensionally formed object can be prevented. Accordingly, the number of steps performed after a three-dimensionally formed object is formed can be reduced. 
     In the method of manufacturing a three-dimensionally formed object according to any one of the examples, in the layer forming step (Steps S 130  and S 140 ), the fluid composition including the constituent material particles and the fluid composition including the support portion-forming particles are ejected in the form of liquid drops to form the layer. Therefore, using a simple method of forming the layer, the three-dimensionally formed object can be formed. 
     In addition, the method of manufacturing a three-dimensionally formed object according to any one of the examples includes a laminating step (Steps S 130  to S 160 ) of repeating the layer forming step (Steps S 130  and S 140 ). Therefore, by repeating the layer forming step, the three-dimensionally formed object can be simply formed. 
     In addition, in the method of manufacturing a three-dimensionally formed object according to any one of the examples, in the energy imparting step (Steps S 150  and S 165 ), the energy is imparted such that a temperature of the constituent material particles and a temperature of the support portion-forming particles are equal to or higher than a sintering temperature of the support portion-forming particles. That is, the constituent material particles are melted, and the support portion-forming particles are sintered. Since the sintering portion can be simply separated from the melting portion, the number of steps performed after a three-dimensionally formed object is formed can be reduced. 
     In addition, in the method of manufacturing a three-dimensionally formed object according to any one of the examples, the layer forming step (Steps S 130  and S 140 ) is adjusted such that a thickness of a layer including the constituent material particles and a thickness of a layer including the support portion-forming particles which correspond to the layer match with each other after the energy imparting step (Steps S 150  and S 165 ). Specifically, a change (reduction degree) in the thickness of the constituent layer caused by melting and a change (reduction degree) in the thickness of the support layer caused by sintering are calculated in advance, and a difference between the changes of the two layers is calculated to adjust the thickness of each of the layers (the amount of liquid drops ejected). Therefore, since there is no difference in the thickness between the support layer and the constituent layer, it is not necessary to adjust the thicknesses of the layers, and a high-precision three-dimensionally formed object can be manufactured. 
     In addition, in the method of manufacturing a three-dimensionally formed object according to the example shown in  FIG. 10 , the energy imparting step (Step S 150 ) is performed whenever the laminating step (Steps S 130  to Steps S 160 ) is performed once to form a layer. In addition, in the method of manufacturing a three-dimensionally formed object according to the example shown in  FIG. 12 , the energy imparting step (Step S 165 ) is performed after completion of the laminating step (Steps S 130  to Steps S 160 ). In other words, in the method of manufacturing a three-dimensionally formed object according to any one of the examples, the energy imparting step is performed after performing the layer forming step (Steps S 130  and S 140 ) once or multiple times to form one layer or plural layers. For example, by performing the energy imparting step after performing the layer forming step multiple times to form plural layers, the number of times of performing the constituent layer forming step can be reduced, and a three-dimensionally formed object can be rapidly manufactured. By performing the energy imparting step once to form a layer, even in a case where one material is disposed to cover the other material on an inclined surface or the like, the two materials are exposed to the same surface in each of the layers, and thus energy can be appropriately imparted to each of the materials. 
     In addition, in the method of manufacturing a three-dimensionally formed object according to any one of the examples, in the energy imparting step (Steps S 150  and S 165 ), the same intensity of energy is imparted to the constituent material particles and the support portion-forming particles (the constituent material particles and the support portion-forming particles are irradiated with electromagnetic waves by the heating portion  1700  in Step S 150 , and the constituent material particles and the support portion-forming particles are collectively heated in the thermostatic chamber (not shown) in Step S 165 ). Therefore, the energy imparting step can be simply performed. 
     In the energy imparting step, different intensities of energy may be imparted to the constituent material particles and the support portion-forming particles. By imparting different intensities of energy, melting or excessive sintering of other regions of the layer excluding the region corresponding to the three-dimensionally formed object can be effectively prevented, and when an extracting operation of extracting the three-dimensionally formed object, a forming operation after the extracting operation, or the like is performed, an increase in load can be prevented. 
     In addition, in the method of manufacturing a three-dimensionally formed object according to any one of the examples, a porosity of a layer including the constituent material particles is lower than a porosity of a layer including the support portion-forming particles which corresponds to the layer after the energy imparting step (Steps S 150  and S 165 ). Therefore, when an extracting operation of extracting the three-dimensionally formed object, a forming operation after the extracting operation, or the like is performed, an increase in load caused by an excessively low porosity of the layer including the support portion-forming particles can be prevented. 
     In addition, in the method of manufacturing a three-dimensionally formed object according to any one of the examples, a porosity of a layer including the support portion-forming particle after the energy imparting step (Steps S 150  and S 165 ) is adjusted to be lower than that before the energy imparting step. Therefore, the strength of the support portion is improved, and there is an advantageous effect in that, before an extracting operation of extracting a three-dimensionally formed object, the three-dimensionally formed object can be reliably held. 
     In addition, it is preferable that the constituent material particles include at least one component of aluminum, titanium, iron, copper, magnesium, stainless steel, or maraging steel and that the support portion-forming particles include at least one component of silica, alumina, titanium oxide, or zirconium oxide. In the energy imparting step, the constituent material particles can be easily controlled to be melted, and the support portion-forming particles can be controlled to have a low sintered density. While securing the strength of the three-dimensionally formed object, an increase in the load of an extracting operation of extracting the three-dimensionally formed object, a forming operation after the extracting operation, or the like can be prevented. 
     The invention is not limited to the above-described examples and can be realized in various embodiments within a range not departing from the scope of the invention. For example, the technical features of any one of the examples corresponding to the technical features of any one of the embodiments described in “Summary” can be appropriately replaced or combined in order to solve a part or all of the above-described problems or to achieve a part or all of the above-described effects. In addition, the technical features may be appropriately omitted unless they are described as essential features in this specification. 
     The present application is a continuation of U.S. patent application Ser. No. 15/292,005, filed Oct. 12, 2016, which claims priority to Japanese Patent Application No. 2015-203487, filed Oct. 15, 2015, the entire disclosures of which are expressly incorporated by reference herein.