Patent Publication Number: US-2018029124-A1

Title: Three-dimensional shaped article shaping stage, three-dimensional shaped article production apparatus, and three-dimensional shaped article production method

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to a three-dimensional shaped article shaping stage, a three-dimensional shaped article production apparatus, and a three-dimensional shaped article production method. 
     2. Related Art 
     Heretofore, there have been used a production apparatus for producing a three-dimensional shaped article by stacking layers. In such a three-dimensional shaped article production apparatus, a stacked body of a three-dimensional shaped article is formed on a shaping plate. 
     For example, JP-A-2010-100883 (Patent Document 1) discloses a production method for producing a three-dimensional shaped article using a three-dimensional shaped article production apparatus capable of forming a stacked body of a three-dimensional shaped article on a shaping plate (shaping stage). 
     When a three-dimensional shaped article is produced on a shaping stage, it is necessary to separate a stacked body of the three-dimensional shaped article formed on the shaping stage from the shaping stage. However, in such a case, the shaping stage and the stacked body of the three-dimensional shaped article are strongly adhered to each other, and the stacked body is not detached from the shaping stage in some cases. In such a case, a part of the stacked body of the three-dimensional shaped article or the shaping stage has to be destroyed or cut or the like. Patent Document 1 describes that as the material of the shaping stage, a material having a low bonding property to the three-dimensional shaped article is desired. However, in the case where the shaping stage is configured to be attachable to and detachable from a three-dimensional shaped article production apparatus, and a stacked body of a three-dimensional shaped article is configured to be degreased or sintered along with the shaping stage, and so on, there is a limitation on the material of the shaping plate. Therefore, in a three-dimensional shaped article production apparatus in the related art as described in Patent Document 1, it is sometimes difficult to easily separate the stacked body of the three-dimensional shaped article from the shaping stage. 
     SUMMARY 
     An advantage of some aspects of the invention is to easily separate a stacked body of a three-dimensional shaped article formed by stacking layers on an attachable and detachable shaping stage from the shaping stage. 
     A first aspect of the invention is directed to a three-dimensional shaped article shaping stage, which is used in a three-dimensional shaped article production apparatus for producing a three-dimensional shaped article by stacking layers to form a stacked body, is attachable to and detachable from the production apparatus, and has a forming surface on which the stacked body is to be formed, and in which an organic film having a lower melting point than a constituent material of the three-dimensional shaped article is formed on the forming surface. 
     The shaping stage according to this aspect of the invention is a shaping stage, which is attachable to and detachable from a three-dimensional shaped article production apparatus, and in which an organic film having a lower melting point than a constituent material of the three-dimensional shaped article is formed on a forming surface. Therefore, for example, the organic film can be removed along with a material to be removed accompanying degreasing or sintering of the stacked body of the three-dimensional shaped article at a temperature which is lower than the melting point of the constituent material of the three-dimensional shaped article and higher than the melting point of the organic film, and thus, the stacked body can be easily separated from the shaping stage. Further, by configuring the shaping stage to be attachable to and detachable from the three-dimensional shaped article production apparatus, when the stacked body of the three-dimensional shaped article is transferred to a device for performing degreasing or sintering, the stacked body can be transferred along with the shaping stage, and therefore, breakage of the stacked body can be suppressed. 
     The “organic film having a lower melting point than the constituent material” refers to a film which covers at least a part of the forming surface and may contain an organic component having a lower melting point than the constituent material. 
     A second aspect of the invention is directed to the three-dimensional shaped article shaping stage, in which the organic film contains a component having a higher melting point than the constituent material. 
     According to this aspect of the invention, the organic film contains a component having a higher melting point than the constituent material of the three-dimensional shaped article. Therefore, when the stacked body of the three-dimensional shaped article formed on the shaping stage is degreased or sintered, the component having a high melting point remains on the shaping stage as a release material after degreasing or sintering, and the stacked body can be particularly easily separated from the shaping stage. 
     A third aspect of the invention is directed to the three-dimensional shaped article shaping stage according to the first or second aspect of the invention, in which the organic film contains an acrylic resin. 
     According to this aspect of the invention, the organic film contains an acrylic resin. The acrylic resin has a low melting point, and carbon derived from the acrylic resin hardly remains on the shaping stage after degreasing or sintering, and therefore, mixing of carbon as an impurity in the stacked body of the three-dimensional shaped article after degreasing or sintering can be suppressed. 
     A fourth aspect of the invention is directed to the three-dimensional shaped article shaping stage according to any one of the first to third aspects of the invention, in which the shaping stage is constituted by a high-melting point material having a higher melting point than the constituent material, and the high-melting point material contains at least one of alumina, silicon carbide, and zirconia. 
     According to this aspect of the invention, the high-melting point material contains at least one of alumina, silicon carbide, and zirconia. These materials have a high melting point and are hardly deformed even at a high temperature, and therefore, it is possible to suppress deformation of the stacked body of the three-dimensional shaped article formed on the shaping stage accompanying degreasing or sintering of the stacked body. 
     A fifth aspect of the invention is directed to a three-dimensional shaped article production apparatus for producing a three-dimensional shaped article by forming a stacked body on the forming surface of the shaping stage according to any one of the first to fourth aspects of the invention. 
     According to this aspect of the invention, the shaping stage is attachable to and detachable from the three-dimensional shaped article production apparatus, and an organic film having a lower melting point than a constituent material of the three-dimensional shaped article is formed on the forming surface on which the stacked body is to be formed. Therefore, the organic film can be removed along with a material to be removed accompanying degreasing or sintering of the stacked body of the three-dimensional shaped article, and thus, the stacked body can be easily separated from the shaping stage. 
     A sixth aspect of the invention is directed to a three-dimensional shaped article production method including forming a stacked body on the forming surface of the shaping stage according to any one of the first to fourth aspects of the invention, applying energy to the stacked body to decompose the organic film. 
     According to this aspect of the invention, the organic film can be removed along with a material to be removed in the applying of the energy accompanying degreasing or sintering of the stacked body of the three-dimensional shaped article formed by stacking layers on the shaping stage in the forming of the stacked body, and therefore, the stacked body can be easily separated from the shaping stage. 
     A seventh aspect of the invention is directed to the three-dimensional shaped article production method according to the sixth aspect of the invention, in which forming the organic film on the forming surface is performed before the forming of the stacked body. 
     According to this aspect of the invention, the forming of the organic film on the forming surface is performed before the forming of the stacked body. Therefore, a shaping stage on which an organic film is not formed in advance can be used. 
     An eighth aspect of the invention is directed to the three-dimensional shaped article production method according to the sixth or seventh aspect of the invention, in which sintering or melting a constituent material is performed after the applying the energy. 
     According to this aspect of the invention, the sintering or melting of the constituent material is performed after the applying the energy. Therefore, the stacked body of the three-dimensional shaped article degreased in the applying of the energy can be sintered or melted. 
    
    
     
       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 schematic configuration view showing a configuration of a three-dimensional shaped article production apparatus according to an embodiment of the invention, and  FIG. 1B  is an enlarged view of a portion C shown in  FIG. 1A . 
         FIG. 2A  is a schematic configuration view showing a configuration of a three-dimensional shaped article production apparatus according to an embodiment of the invention, and  FIG. 2B  is an enlarged view of a portion C′ shown in  FIG. 2A . 
         FIG. 3  is a schematic perspective view of a head base according to an embodiment of the invention. 
         FIG. 4A  is a plan view conceptually illustrating the relationship between the arrangement of head units and the forming form of a three-dimensional shaped article according to an embodiment of the invention;  FIG. 4B  is a plan view conceptually illustrating the relationship between the arrangement of head units and the forming form of a three-dimensional shaped article according to an embodiment of the invention; and  FIG. 4C  is a plan view conceptually illustrating the relationship between the arrangement of head units and the forming form of a three-dimensional shaped article according to an embodiment of the invention. 
         FIG. 5A  is a schematic view conceptually illustrating the forming form of a three-dimensional shaped article; and  FIG. 5B  is a schematic view conceptually illustrating the forming form of a three-dimensional shaped article. 
         FIG. 6A  is a schematic view showing an example of other arrangements of head units arranged in a head base; and  FIG. 6B  is a schematic view showing an example of other arrangements of head units arranged in a head base. 
         FIG. 7  is a schematic view showing a shaping stage according to an embodiment of the invention. 
         FIG. 8  is a flowchart showing a three-dimensional shaped article production method according to an embodiment of the invention. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, embodiments according to the invention will be described with reference to the accompanying drawings. 
       FIGS. 1A to 2B  are schematic configuration views showing a configuration of a three-dimensional shaped article production apparatus according to an embodiment of the invention. 
     Here, the three-dimensional shaped article production apparatus according to this embodiment includes two types of material supply sections (head bases). Among these,  FIGS. 1A and 1B  are views showing one material supply section (a material supply section which supplies a constituent material (a material containing a powder constituting a three-dimensional shaped article, a solvent, and a binder)).  FIGS. 2A and 2B  are views showing another material supply section (a material supply section which supplies a support layer forming material for forming a support layer that supports a three-dimensional shaped article when the three-dimensional shaped article is formed). 
     The “three-dimensional shaping” as used herein refers to the formation of a so-called “three-dimensional shaped article”, and also includes, for example, the formation of a shape with a thickness even if the shape is a plate shape or a so-called two-dimensional shape. Further, the “supporting” as used herein includes supporting from the lower side, and in addition thereto, also includes supporting from the lateral side, and in some cases, supporting from the upper side. 
     Further, the three-dimensional shaped article production apparatus according to this embodiment is configured to be able to form a support layer for supporting a constituent layer of a three-dimensional shaped article when the constituent layer is formed using a constituent material of the three-dimensional shaped article. Therefore, the apparatus is configured to be able to form a convex portion (so-called “overhang portion”) protruding in a direction intersecting the stacking direction without deforming the portion. However, the configuration is not limited thereto, and a configuration in which the support layer is not formed (that is, a configuration in which the support layer forming material is not used) may be adopted. 
     A three-dimensional shaped article production apparatus  2000  (hereinafter referred to as “forming apparatus  2000 ”) shown in  FIGS. 1A to 2B  includes a base  110  and a stage  120  which is provided movably in the X, Y, and Z directions shown in the drawings or drivably in the direction of rotation about the Z axis by a drive device  111  as a drive unit provided for the base  110 . 
     Then, as shown in  FIGS. 1A and 1B , the forming apparatus  2000  includes a head base support section  130 , one end of which is fixed to the base  110 , and to the other end of which, a head base  1100  that holds a plurality of head units  1400  each including a constituent material ejection section  1230  that ejects a constituent material is held and fixed. 
     Further, as shown in  FIGS. 2A and 2B , the forming apparatus  2000  includes a head base support section  730 , one end of which is fixed to the base  110 , and to the other end of which, a head base  1600  that holds a plurality of head units  1900  each including a support layer forming material ejection section  1730  that ejects a material for forming a support layer that supports a three-dimensional shaped article is held and fixed. 
     Here, the head base  1100  and the head base  1600  are provided in parallel in the XY plane. 
     The constituent material ejection section  1230  and the support layer forming material ejection section  1730  have the same configuration. However, the configuration is not limited thereto. 
     On the stage  120 , an attachable and detachable shaping stage  121  is placed, and layers  501 ,  502 , and  503  are formed in the process for forming a stacked body  500  of a three-dimensional shaped article on a forming surface  121   a  (see  FIG. 3 ) of the shaping stage  121 . The stacked body  500  of the three-dimensional shaped article formed on the forming surface  121   a  of the shaping stage  121  is degreased (at least a part of a solvent or a binder contained in the constituent material is decomposed and removed) or sintered by applying energy such as thermal energy after forming the stacked body in the forming apparatus  2000 . Then, the degreasing or sintering of the stacked body  500  of the three-dimensional shaped article is performed by placing the stacked body  500  along with the shaping stage  121  in a thermostatic bath  650  (see  FIG. 7 ) or the like capable of applying thermal energy as an energy application device which is provided separately from the forming apparatus  2000 . Due to this, the shaping stage  121  is required to have high heat resistance. Therefore, by using, for example, a ceramic plate as the shaping stage  121 , high heat resistance can be obtained, and also the reactivity thereof with the constituent material of the three-dimensional shaped article, which is further sintered (or which may be melted) is low, and alteration of the stacked body  500  of the three-dimensional shaped article can be prevented. Incidentally, in  FIGS. 1A and 2A , for the sake of convenience of explanation, three layers: the layers  501 ,  502 , and  503  are shown as examples, however, the layers (up to the layer  50   n  in  FIGS. 1A and 2A ) are stacked until the desired shape of the stacked body  500  of the three-dimensional shaped article is obtained. 
     Here, the layers  501 ,  502 ,  503 , . . . , and  50   n  are each constituted by a support layer  300  formed from the support layer forming material ejected from the support layer forming material ejection section  1730  and a constituent layer  310  formed from the constituent material ejected from the constituent material ejection section  1230 . 
       FIG. 1B  is an enlarged conceptual view of a portion C showing the head base  1100  shown in  FIG. 1A . As shown in  FIG. 1B , the head base  1100  holds a plurality of head units  1400 . Although a detailed description will be given later, each head unit  1400  is configured such that the constituent material ejection section  1230  included in a constituent material supply device  1200  is held by a holding jig  1400   a . The constituent material ejection section  1230  includes an ejection nozzle  1230   a  and an ejection drive section  1230   b  that allows the constituent material to be ejected from the ejection nozzle  1230   a  by a material supply controller  1500 . 
       FIG. 2B  is an enlarged conceptual view of a portion C′ showing the head base  1600  shown in  FIG. 2A . Here, the head base  1600  has the same configuration as that of the head base  1100 . Specifically, as shown in  FIG. 2B , the head base  1600  holds a plurality of head units  1900 . Each head unit  1900  is configured such that the support layer forming material ejection section  1730  included in a support layer forming material supply device  1700  is held by a holding jig  1900   a . The support layer forming material ejection section  1730  includes an ejection nozzle  1730   a  and an ejection drive section  1730   b  that allows the support layer forming material to be ejected from the ejection nozzle  1730   a  by the material supply controller  1500 . 
     Although not included in the forming apparatus  2000  according to this embodiment, an energy application section capable of degreasing or sintering the constituent material ejected from the constituent material ejection section  1230  or the support layer forming material ejected from the support layer forming material ejection section  1730  may be included. By including such an energy application section, the necessity to separately provide an energy application device can be eliminated. The configuration of the energy application section or the energy application device is not particularly limited, however, examples thereof include, in addition to the thermostatic bath  650  or the like capable of applying thermal energy, a laser irradiation device including a laser irradiation section and a galvanometer mirror which determines the position of laser light from the laser irradiation section, and an electromagnetic wave (infrared light, ultraviolet light, or the like) irradiation device. 
     As shown in  FIGS. 1A and 1B , the constituent material ejection section  1230  is connected to a constituent material supply unit  1210  which houses a constituent material made to correspond to each head unit  1400  held by the head base  1100  through a supply tube  1220 . Then, a given constituent material is supplied to the constituent material ejection section  1230  from the constituent material supply unit  1210 . In the constituent material supply unit  1210 , the constituent material of the stacked body  500  of the three-dimensional shaped article to be shaped by the forming apparatus  2000  according to this embodiment is housed in a constituent material housing section  1210   a,  and each individual constituent material housing section  1210   a  is connected to each individual constituent material ejection section  1230  through the supply tube  1220 . In this manner, by including the individual constituent material housing sections  1210   a,  a plurality of different types of materials can be supplied from the head base  1100 . 
     As shown in  FIGS. 2A and 2B , the support layer forming material ejection section  1730  is connected to a support layer forming material supply unit  1710  which houses a support layer forming material made to correspond to each head unit  1900  held by the head base  1600  through a supply tube  1720 . Then, a given support layer forming material is supplied to the support layer forming material ejection section  1730  from the support layer forming material supply unit  1710 . In the support layer forming material supply unit  1710 , the support layer forming material constituting a support layer when shaping the stacked body  500  of the three-dimensional shaped article is housed in a support layer forming material housing section  1710   a,  and each individual support layer forming material housing section  1710   a  is connected to each individual support layer forming material ejection section  1730  through the supply tube  1720 . In this manner, by including the individual support layer forming material housing sections  1710   a,  a plurality of different types of support layer forming materials can be supplied from the head base  1600 . 
     As the constituent material and the support layer forming material, for example, a simple substance powder of magnesium (Mg), iron (Fe), cobalt (Co), chromium (Cr), aluminum (Al), titanium (Ti), copper, (Cu), or nickel (Ni), or a mixed powder of an alloy containing at least one metal among these (a maraging steel, stainless steel, cobalt-chrome-molybdenum, a titanium alloy, a nickel alloy, an aluminum alloy, a cobalt alloy, or a cobalt-chromium alloy) or the like can be used by being formed into a mixed material or the like in the form of a slurry (or a paste) containing a solvent and a binder. 
     It is also possible to use general purpose engineering plastics such as polyamide, polyacetal, polycarbonate, modified polyphenylene ether, polybutylene terephthalate, and polyethylene terephthalate. In addition thereto, it is also possible to use engineering plastics such as polysulfone, polyethersulfone, polyphenylene sulfide, polyarylate, polyimide, polyamideimide, polyetherimide, and polyether ether ketone. 
     In this manner, the constituent material and the support layer forming material are not particularly limited, and a metal other than the above-mentioned metals, a ceramic, a resin, or the like can also be used. Further, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, or the like can also be preferably used. 
     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, and propylene glycol monoethyl ether; acetate esters such as ethyl acetate, n-propyl acetate, iso-propyl acetate, n-butyl acetate, and iso-butyl acetate; aromatic hydrocarbons such as benzene, toluene, and xylene; ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, ethyl n-butyl ketone, diisopropyl ketone, and acetyl acetone; alcohols such as ethanol, propanol, and butanol; tetra-alkyl ammonium acetates; sulfoxide-based solvents such as dimethyl sulfoxide and diethyl sulfoxide; pyridine-based solvents such as pyridine, γ-picoline, and 2,6-lutidine; and ionic liquids such as tetra-alkyl ammonium acetate (for example, tetra-butyl ammonium acetate, etc.), and one type or two or more types in combination selected from these can be used. 
     As the binder, for example, an acrylic resin, an epoxy resin, a silicone resin, a cellulosic resin, or another synthetic resin, or PLA (polylactic acid), PA (polyamide), PPS (polyphenylene sulfide), or another thermoplastic resin can be used. Further, a UV curable resin which is polymerized by irradiation with UV light may be used as the binder. 
     The forming apparatus  2000  includes a control unit  400  as a control device which controls the stage  120 , the constituent material ejection section  1230  included in the constituent material supply device  1200 , and the support layer forming material ejection section  1730  included in the support layer forming material supply device  1700  based on the data for shaping a three-dimensional shaped article to be output from a data output device such as, for example, a personal computer (not shown). The control unit  400  includes a control section (not shown) which controls the stage  120  and the constituent material ejection section  1230  so that these members are driven and operated in cooperation with each other, and also controls the stage  120  and the support layer forming material ejection section  1730  so that these members are driven and operated in cooperation with each other. 
     The stage  120  provided movably for the base  110  is controlled such that a signal for controlling the start and stop of movement, the direction of movement, the amount of movement, the speed of movement, or the like of the stage  120  is generated in a stage controller  410  based on a control signal from the control unit  400  and sent to the drive device  111  provided for the base  110 , and the stage  120  moves in the X, Y, or Z direction shown in the drawing. In the constituent material ejection section  1230  included in the head unit  1400 , a signal for controlling the amount of the material ejected from the ejection nozzle  1230   a  in the ejection drive section  1230   b  included in the constituent material ejection section  1230  or the like is generated in the material supply controller  1500  based on the control signal from the control unit  400 , and a predetermined amount of the constituent material is ejected from the ejection nozzle  1230   a  based on the generated signal. 
     In the same manner, in the support layer forming material ejection section  1730  included in the head unit  1900 , a signal for controlling the amount of the material ejected from the ejection nozzle  1730   a  in the ejection drive section  1730   b  included in the support layer forming material ejection section  1730  or the like is generated in the material supply controller  1500  based on a control signal from the control unit  400 , and a predetermined amount of the support layer forming material is ejected from the ejection nozzle  1730   a  based on the generated signal. 
     Next, the head unit  1400  will be described in further detail. The head unit  1900  has the same configuration as that of the head unit  1400 , and therefore, a description of the detailed configuration of the head unit  1900  will be omitted. 
       FIGS. 3 to 4C  show one example of the holding form of a plurality of head units  1400  and the constituent material ejection sections  1230  held by the head base  1100 , and among these,  FIGS. 4A to 4C  are external views of the head base  1100  viewed from the direction of the arrow D shown in  FIG. 1B . 
     As shown in  FIG. 3 , a plurality of head units  1400  are held by the head base  1100  through a fixing unit (not shown). Further, as shown in  FIGS. 4A to 4C , in the head base  1100  of the forming apparatus  2000  according to this embodiment, the head units  1400  are included such that the following 4 units: a head unit  1401  in the first row from the lower side in the drawing, a head unit  1402  in the second row, a head unit  1403  in the third row, and a head unit  1404  in the fourth row are arranged in a staggered manner (alternately). Then, as shown in  FIG. 4A , while moving the stage  120  in the X direction with respect to the head base  1100 , the constituent material is ejected from each head unit  1400 , whereby constituent layer constituting parts  50  (constituent layer constituting parts  50   a,    50   b,    50   c,  and  50   d ) are formed. The procedure for forming the constituent layer constituting parts  50  will be described later. 
     Incidentally, although not shown in the drawing, the constituent material ejection sections  1230  included in the respective head units  1401  to  1404  are configured to be connected to the constituent material supply unit  1210  through the ejection drive section  1230   b  with the supply tube  1220 . 
     As shown in  FIG. 3 , the constituent material ejection section  1230  ejects a material M which is the constituent material of the three-dimensional shaped article from the ejection nozzle  1230   a  to the forming surface  121   a  of the shaping stage  121  placed on the stage  120 . In the head unit  1401 , an ejection form in which the material M is ejected in the form of a liquid droplet is illustrated, and in the head unit  1402 , an ejection form in which the material M is supplied in the form of a continuous body is illustrated. The ejection form of the material M may be in the form of either a liquid droplet or a continuous body, however, in this embodiment, a description will be given by showing a configuration in which the material M is ejected in the form of a liquid droplet. 
     Incidentally, the constituent material ejection section  1230  and the support layer forming material ejection section  1730  are not limited to such a configuration, and may be a material supply section employing a different system such as an extruder. 
     The material M ejected in the form of a liquid droplet from the ejection nozzle  1230   a  flies substantially in the direction of gravity and lands on the shaping stage  121 . The stage  120  moves, and by the material M landing on the shaping stage  121 , the constituent layer constituting parts  50  are formed. An assembly of the constituent layer constituting parts  50  is formed as the constituent layer  310  (see  FIG. 1A ) of the stacked body  500  of the three-dimensional shaped article to be formed on the forming surface  121   a  of the shaping stage  121 . 
     Next, the procedure for forming the constituent layer constituting parts  50  will be described with reference to  FIGS. 4A to 5B . 
       FIGS. 4A to 4C  are plan views conceptually illustrating the relationship between the arrangement of the head units  1400  of this embodiment and the forming form of the constituent layer constituting parts  50 .  FIGS. 5A and 5B  are side views conceptually illustrating the forming form of the constituent layer constituting parts  50 . 
     First, when the stage  120  moves in the +X direction, the material M is ejected in the form of a liquid droplet from the plurality of ejection nozzles  1230   a,  and the material M is placed at predetermined positions on the forming surface  121   a  of the shaping stage  121 , and therefore, the constituent layer constituting parts  50  are formed. 
     More specifically, first, as shown in  FIG. 5A , while moving the stage  120  in the +X direction, the material M is placed at predetermined positions at regular intervals on the forming surface  121   a  of the shaping stage  121  from the plurality of ejection nozzles  1230   a.    
     Subsequently, as shown in  FIG. 5B , while moving the stage  120  in the −X direction shown in  FIG. 1A , the material M is newly placed so as to fill the gap between the materials M placed at regular intervals. 
     However, a configuration in which while moving the stage  120  in the +X direction, the material M is ejected from the plurality of ejection nozzles  1230   a  at predetermined positions on the shaping stage  121  so that the materials M overlap with each other (so as not to form a gap) (not a configuration in which the constituent layer constituting parts  50  are formed by the reciprocation of the stage  120  in the X direction, but a configuration in which the constituent layer constituting parts  50  are formed by only one way movement of the stage  120  in the X direction) may be adopted. 
     By forming the constituent layer constituting parts  50  as described above, the constituent layer constituting parts  50  (the constituent layer constituting parts  50   a,    50   b,    50   c , and  50   d ) (of the first line in the Y direction) for one line in the X direction of the respective head units  1401 ,  1402 ,  1403 , and  1404  as shown in  FIG. 4A  are formed. 
     Subsequently, in order to form constituent layer constituting parts  50 ′ (constituent layer constituting parts  50   a ′,  50   b ′,  50   c ′, and  50   d ′) of the second line in the Y direction of the respective head units  1401 ,  1402 ,  1403 , and  1404 , the head base  1100  is moved in the −Y direction. As for the amount of movement, when the pitch between the nozzles is represented by P, the head base  1100  is moved in the −Y direction by a distance of P/n (n represents a natural number). In this embodiment, a description will be given by assuming that n is 3. 
     By performing the same operation as described above as shown in  FIGS. 5A and 5B , the constituent layer constituting parts  50 ′ (constituent layer constituting parts  50   a ′,  50   b ′,  50   c ′, and  50   d ′) of the second line in the Y direction as shown in  FIG. 4B  are formed. 
     Subsequently, in order to form constituent layer constituting parts  50 ″ (constituent layer constituting parts  50   a ″,  50   b ″,  50   c ″, and  50   d ″) of the third line in the Y direction of the respective head units  1401 ,  1402 ,  1403 , and  1404 , the head base  1100  is moved in the −Y direction. As for the amount of movement, the head base  1100  is moved in the −Y direction by a distance of P/3. 
     Then, by performing the same operation as described above as shown in  FIGS. 5A and 5B , the constituent layer constituting parts  50 ″ (constituent layer constituting parts  50   a ″,  50   b ″,  50   c ″, and  50   d ″) of the third line in the Y direction as shown in  FIG. 4C  are formed, and thus, the constituent layer  310  can be obtained. 
     Further, as for the material M ejected from the constituent material ejection section  1230 , from any one unit or two or more units of the head units  1401 ,  1402 ,  1403 , and  1404 , a constituent material different from the other head units can also be ejected and supplied. Therefore, by using the forming apparatus  2000  according to this embodiment, a three-dimensional shaped article formed from different materials can be obtained. 
     Incidentally, in the layer  501  as the first layer, before or after forming the constituent layer  310  as described above, by ejecting the support layer forming material from the support layer forming material ejection section  1730 , the support layer  300  can be formed in the same manner as described above. Then, also when the layers  502 ,  503 , . . . , and  50   n  are formed by being stacked on the layer  501 , the constituent layer  310  and the support layer  300  can be formed in the same manner as described above. 
     The number and arrangement of the head units  1400  and  1900  included in the forming apparatus  2000  according to this embodiment described above are not limited to the above-mentioned number and arrangement.  FIGS. 6A and 6B  schematically show examples of other arrangement of the head units  1400  placed in the head base  1100 . 
       FIG. 6A  shows a form in which a plurality of head units  1400  are arranged in parallel in the X-axis direction in the head base  1100 .  FIG. 6B  shows a form in which the head units  1400  are arranged in a lattice pattern in the head base  1100 . The number of head units to be arranged is not limited to the examples shown in  FIGS. 6A and 6B  in either case. 
     Next, the shaping stage  121  which is a principal part of the forming apparatus  2000  according to this embodiment described above will be described in further detail. 
       FIG. 7  is a schematic view showing the shaping stage  121  of this embodiment. More specifically, a state where the shaping stage  121  on which the stacked body  500  of the three-dimensional shaped article is formed is placed in the thermostatic bath  650  as the energy application device and subjected to degreasing is shown. 
     The shaping stage  121  of this embodiment is used in the forming apparatus  2000  for producing the three-dimensional shaped article by stacking layers to form the stacked body  500  of the three-dimensional shaped article as described above, and has the forming surface  121   a  on which the stacked body  500  of the three-dimensional shaped article is formed as shown in  FIG. 7 . 
     The shaping stage  121  is formed into a porous structure using a high-melting point material having a higher melting point than the constituent material of the three-dimensional shaped article. Therefore, the shaping stage  121  of this embodiment is configured such that when the stacked body  500  of the three-dimensional shaped article formed by stacking layers on the shaping stage  121  is degreased or sintered, the difference between a manner of volatilization of a material to be removed (such as a solvent or a binder contained in the constituent material) from the shaping stage  121  side (downward direction) and a manner of volatilization of the material to be removed from on the shaping stage  121  (upward direction and lateral direction) (that is, the difference in the shrinkage ratio) can be decreased. Accordingly, the shaping stage  121  is configured such that deformation of the stacked body  500  of the three-dimensional shaped article formed by stacking layers on the shaping stage  121  accompanying degreasing or sintering of the stacked body  500  of the three-dimensional shaped article can be suppressed. 
     The arrows in  FIG. 7  conceptually show the direction in which the material to be removed is volatilized. In the case where the shaping stage  121  is not formed into a porous structure, volatilization of the material to be removed from the shaping stage  121  side (the downward arrows) hardly occurs, and a portion on the shaping stage  121  side is less shrunk than the other portions. 
     Further, the shaping stage  121  of this embodiment is attachable to and detachable from the forming apparatus  2000 , and an organic film  600  having a lower melting point than the constituent material is formed on the forming surface  121   a . Therefore, the shaping stage  121  is configured such that, for example, the organic film  600  can be removed along with the material to be removed accompanying degreasing or sintering of the stacked body  500  of the three-dimensional shaped article at a temperature which is lower than the melting point of the constituent material of the three-dimensional shaped article and higher than the melting point of the organic film  600 , and thus, deformation of the stacked body  500  of the three-dimensional shaped article can be particularly effectively suppressed, and also the stacked body  500  of the three-dimensional shaped article after degreasing or sintering can be easily separated from the shaping stage  121 . This is because the stacked body  500  of the three-dimensional shaped article is shrunk when it is degreased or sintered, however, by forming the organic film  600 , it is possible to suppress shrinkage of the stacked body  500  of the three-dimensional shaped article by degreasing or sintering while confining the constituent material to the rough forming surface  121   a.  In particular, in the case where the shaping stage  121  is formed into a porous structure as in this embodiment, the roughness of the forming surface  121   a  tends to increase, and therefore, the effect of formation of the organic film  600  is particularly large. 
     Moreover, by configuring the shaping stage  121  to be attachable to and detachable from the forming apparatus  2000 , when the stacked body  500  of the three-dimensional shaped article is transferred to the energy application device (thermostatic bath  650 ) for performing degreasing or sintering, the stacked body  500  can be transferred along with the shaping stage  121 . Therefore, it is possible to suppress breakage of the stacked body  500  of the three-dimensional shaped article accompanying detachment of the stacked body  500  of the three-dimensional shaped article from the shaping stage  121  for placing the stacked body in the thermostatic bath  650 . 
     It goes without saying that the shaping stage  121  in which the organic film  600  is formed in advance is prepared, and the stacked body  500  of the three-dimensional shaped article may be formed on the shaping stage  121 . However, the shaping stage  121  in which the organic film  600  is not formed in advance is prepared, and prior to the formation of the stacked body  500  of the three-dimensional shaped article, the support layer forming material is ejected from the support layer forming material ejection section  1730 , thereby forming the organic film  600  on the forming surface  121   a,  and thereafter, the stacked body  500  of the three-dimensional shaped article may be formed. It goes without saying that the shaping stage  121  in which the organic film  600  is formed on the forming surface  121   a  in this manner is also included in the invention. 
     Further, the “organic film having a lower melting point than the constituent material” refers to a film which covers at least a part of the forming surface  121   a  and may contain an organic component having a lower melting point than the constituent material. 
     Here, the organic film  600  formed in the shaping stage  121  of this embodiment contains an acrylic resin. The acrylic resin has a low melting point, and carbon derived from the acrylic resin hardly remains on the shaping stage  121  after degreasing or sintering, and therefore, mixing of carbon as an impurity in the stacked body  500  of the three-dimensional shaped article after degreasing or sintering can be suppressed. 
     However, the forming component of the organic film  600  is not particularly limited, and a polyester resin or the like can be used other than the acrylic resin, and also a plurality of types of resins may be contained. 
     Further, the organic film  600  may contain a component having a higher melting point than the constituent material. This is because by including a component having a higher melting point than the constituent material in the organic film  600 , when the stacked body  500  of the three-dimensional shaped article formed on the shaping stage  121  is degreased or sintered, the component having a high melting point uniformly remains on the shaping stage  121  as a release material after degreasing or sintering, and therefore, the stacked body  500  of the three-dimensional shaped article can be separated from the shaping stage  121  particularly easily (in a short time). 
     The “component having a higher melting point than the constituent material” is not particularly limited, however, for example, a ceramic (alumina, silicon carbide, zirconia, or the like) can be used. 
     Further, the high-melting point material in the shaping stage  121  preferably contains at least one of alumina, silicon carbide, and zirconia. This is because these materials have a high melting point and are hardly deformed even at a high temperature, and therefore, it is possible to particularly effectively suppress deformation of the stacked body  500  of the three-dimensional shaped article formed on the shaping stage  121  accompanying degreasing or sintering of the stacked body  500  of the three-dimensional shaped article. 
     In this manner, the forming apparatus  2000  of this embodiment is an apparatus for producing a three-dimensional shaped article by forming the stacked body  500  of the three-dimensional shaped article on the forming surface  121   a  of the shaping stage  121  as described above. Then, according to such a configuration, when the stacked body  500  of the three-dimensional shaped article formed by stacking layers on the shaping stage  121  is degreased or sintered, the difference between a manner of volatilization of the material to be removed from the shaping stage  121  side and a manner of volatilization of the material to be removed from on the shaping stage  121  can be decreased. Therefore, the forming apparatus  2000  of this embodiment is configured to be able to suppress deformation of the stacked body  500  of the three-dimensional shaped article formed by stacking layers on the shaping stage  121  accompanying degreasing or sintering of the stacked body  500  of the three-dimensional shaped article. 
     Further, the forming apparatus  2000  of this embodiment is configured such that the organic film  600  having a lower melting point than the constituent material of the three-dimensional shaped article is formed on the forming surface  121   a  of the shaping stage  121  which is attachable to and detachable from the apparatus, and therefore, the organic film  600  can be removed along with the material to be removed accompanying degreasing or sintering of the stacked body  500  of the three-dimensional shaped article, and thus, the stacked body  500  of the three-dimensional shaped article can be easily separated from the shaping stage  121 . 
     Next, one example of the three-dimensional shaped article production method to be performed using the above-mentioned forming apparatus  2000  will be described with reference to a flowchart. 
     Here,  FIG. 8  is a flowchart of the three-dimensional shaped article production method according to this embodiment. 
     As shown in  FIG. 8 , in the three-dimensional shaped article production method according to this embodiment, first, in Step S 110 , the data of the three-dimensional shaped article is acquired. More specifically, the data representing the shape of the three-dimensional shaped article is acquired from, for example, an application program or the like executed by a personal computer. 
     Subsequently, in Step S 120 , data for each layer are created. More specifically, the data representing the shape of the three-dimensional shaped article is sliced according to the shaping resolution in the Z direction, and bitmap data (cross-sectional data) are created for each cross section. 
     Subsequently, in the case where the shaping stage  121  in which the organic film  600  is not formed is prepared, in Step S 130 , the support layer forming material is ejected from the support layer forming material ejection section  1730 , whereby the organic film  600  is formed on the forming surface  121   a.  However, in the case where the shaping stage  121  in which the organic film  600  is formed in advance is prepared, this step can be omitted. 
     Subsequently, in Step S 140 , the stacked body  500  of the three-dimensional shaped article is formed based on the data for each layer created in Step S 120 . Then, Step S 140  and Step S 150  are repeated until the data for each layer is completed in Step S 150 , whereby the stacked body  500  of the three-dimensional shaped article is completed on the forming surface  121   a  of the shaping stage  121 . 
     In Step S 140  to Step S 150 , in the three-dimensional shaped article production method according to this embodiment, the stacked body  500  of the three-dimensional shaped article is formed (the constituent layer constituting parts  50  are fixed) by volatilizing the solvent naturally without particularly applying energy, however, the constituent layer constituting parts  50  may be fixed by applying energy such as heating. 
     Subsequently, in Step S 160 , the stacked body  500  of the three-dimensional shaped article is taken out from the forming apparatus  2000  along with the shaping stage  121 , and placed in the thermostatic bath  650  as the energy application device, and then, energy is applied (heating is performed). The organic component of the organic film  600  is decomposed and removed in this step. 
     In the end, in Step S 170 , the output of energy in the thermostatic bath  650  is increased to heat the stacked body  500  of the three-dimensional shaped article, and the three-dimensional shaped article production method according to this embodiment is completed. 
     In the case where Step S 160  is an energy application step corresponding to degreasing, Step S 170  corresponds to a heating step corresponding to sintering or melting, and in the case where Step S 160  is an energy application step corresponding to degreasing and sintering, Step S 170  corresponds to a heating step corresponding to melting. Further, in the case where it is not necessary to perform sintering or melting, for example, in the case where the stacked body  500  of the three-dimensional shaped article is completed by degreasing or in the case where the stacked body  500  of the three-dimensional shaped article is completed by sintering, Step S 170  can be omitted. 
     In this manner, the three-dimensional shaped article production method according to this embodiment includes a stacked body formation step (Step S 140 ) of forming the stacked body  500  of the three-dimensional shaped article on the forming surface  121   a  using the shaping stage  121  described above and an energy application step (Step S 160 ) of applying energy to the stacked body  500  of the three-dimensional shaped article. 
     Therefore, when the stacked body  500  of the three-dimensional shaped article formed by stacking layers on the shaping stage  121  (formed into a porous structure using a high-melting point material having a higher melting point than the constituent material) in the stacked body formation step is degreased or sintered in the energy application step, the difference between a manner of volatilization of the material to be removed from the shaping stage  121  side (downward direction) and a manner of volatilization of the material to be removed from on the shaping stage  121  (upward direction and lateral direction) can be decreased. Accordingly, it is possible to suppress deformation of the stacked body  500  of the three-dimensional shaped article formed by stacking layers on the shaping stage  121  accompanying degreasing or sintering of the stacked body  500  of the three-dimensional shaped article. 
     Moreover, the organic film  600  can be removed along with the material to be removed in the energy application step accompanying degreasing or sintering of the stacked body  500  of the three-dimensional shaped article formed by stacking layers on the shaping stage  121  (on which the organic film  600  having a lower melting point than the constituent material is formed on the forming surface  121   a ) in the stacked body formation step, and therefore, the stacked body  500  of the three-dimensional shaped article can be easily separated from the shaping stage  121 . 
     Further, in the three-dimensional shaped article production method according to this embodiment, an organic film formation step (Step S 130 ) of forming the organic film  600  on the forming surface  121   a  can be performed before the stacked body formation step (Step S 140 ). Therefore, the shaping stage  121  in which the organic film  600  is not formed in advance can be used. 
     Further, in the three-dimensional shaped article production method according to this embodiment, a heating step (Step S 170 ) of sintering or melting the constituent material of the three-dimensional shaped article can be performed after the energy application step (Step S 160 ). Therefore, the stacked body  500  of the three-dimensional shaped article degreased in the energy application step can be sintered or melted. 
     The invention is not limited to the above-mentioned embodiments, but can be realized in various configurations without departing from the gist of the invention. For example, the technical features in the embodiments corresponding to the technical features in the respective forms described in “SUMMARY” may be appropriately replaced or combined in order to solve part or all of the problems described above or achieve part or all of the advantageous effects described above. Further, the technical features may be appropriately deleted unless they are described as essential features in the specification. 
     The entire disclosure of Japanese Patent No. 2016-146581, filed Jul. 26, 2016 is expressly incorporated by reference herein.