Patent Publication Number: US-2020298484-A1

Title: Molding apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2019-055054 filed Mar. 22, 2019. 
     BACKGROUND 
     (i) Technical Field 
     The present disclosure relates to a molding apparatus. 
     (ii) Related Art 
     International Publication No. 2018/151074 discloses a three-dimensional printing apparatus capable of continuously discharging a filament wire, which is formed of a fiber bundle impregnated with resin. The three-dimensional printing apparatus includes a twisting part capable of changing the degree of twisting of the overall filaments or the degree of twisting of the fiber bundle. 
     SUMMARY 
     In the configuration in which an article is molded from a molding material that is formed of a bundle of continuous fibers spirally twisted and impregnated with resin, the strength of the molding material may decrease. 
     Aspects of non-limiting embodiments of the present disclosure relate to suppressing decrease in strength of the molding material, compared with that in the configuration in which a bundle of continuous fibers are spirally twisted and impregnated with resin. 
     Aspects of certain non-limiting embodiments of the present disclosure address the above advantages and/or other advantages not described above. However, aspects of the non-limiting embodiments are not required to address the advantages described above, and aspects of the non-limiting embodiments of the present disclosure may not address advantages described above. 
     According to an aspect of the present disclosure, there is provided a molding apparatus including: a receiving part on which a wire-shaped molding material that is formed of a bundle of continuous fibers impregnated with resin is discharged; a discharge part that discharges the molding material on the receiving part; and a rotation mechanism that rotates the discharge part to spirally twist the molding material being discharged from the discharge part. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiment of the present disclosure will be described in detail based on the following figures, wherein: 
         FIG. 1  schematically shows the configuration of a molding apparatus according to an exemplary embodiment; 
         FIG. 2  is a sectional view of a bundle of continuous fibers used in the molding apparatus according to this exemplary embodiment; 
         FIG. 3  is a sectional view of a molding material used in the molding apparatus according to this exemplary embodiment; 
         FIG. 4  is a sectional view of the molding material shown in  FIG. 3  in a flattened state; 
         FIG. 5  is a block diagram showing the configuration of a controller of the molding apparatus according to this exemplary embodiment; 
         FIG. 6  shows a portion of an article molded by the molding apparatus according to this exemplary embodiment; and 
         FIG. 7  schematically shows the operation of a discharge part according to this exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An exemplary embodiment of the present disclosure will be described below with reference to the drawings. In  FIG. 1 , arrow H indicates the height direction of the molding apparatus (vertical direction), and arrow W indicates the width direction of the molding apparatus (horizontal direction). The direction intersecting (more specifically, perpendicular to) the height and the width directions of the molding apparatus is the depth direction of the molding apparatus (horizontal direction). 
     Molding Apparatus 
     First, a molding apparatus  10  will be described.  FIG. 1  schematically shows the configuration of the molding apparatus  10 . 
     The molding apparatus  10  shown in  FIG. 1  is an apparatus for molding an article. More specifically, the molding apparatus  10  is a three-dimensional molding apparatus (a so-called 3D printer) employing a so-called fused deposition modeling (FDM) method. The molding apparatus  10  molds an article by forming multiple layers with a molding material  100  according to layer data about the layers. 
     As shown in  FIG. 1 , the molding apparatus  10  according to this exemplary embodiment includes: a molding unit  12 ; a stage  14 ; a moving mechanism  18 ; and a control unit  16 . A molding material  100  (see  FIG. 3 ) used in the molding apparatus  10  is a wire-shaped molding material that is formed of a bundle  110  of continuous fibers  120  (hereinbelow, a fiber bundle  110 ) impregnated with resin  112 . The “wire shape” is a shape having a certain length in one direction, and the sectional shape of the molding material  100  is not specifically limited. Hence, the molding material  100  may have any sectional shape, such as a circular, flat, rectangular, triangular, or square sectional shape. 
     Stage and Moving Mechanism 
     The stage  14  shown in  FIG. 1  is an example receiving part. The molding material  100  is discharged on the stage  14 . More specifically, the molding material  100  discharged on the stage  14  is placed on the stage  14 . An article is molded by the molding material  100  on the stage  14 . The stage  14  may be preheated. 
     As shown in  FIG. 1 , the stage  14  is disposed below the molding unit  12 . The stage  14  includes a receiving surface  14 A, on which the molding material  100  is discharged (in other words, on which the molding material  100  is placed). The receiving surface  14 A is facing the molding unit  12 , that is, the stage  14  is facing up. The receiving surface  14 A is a horizontal surface. 
     The moving mechanism  18  shown in  FIG. 1  moves the stage  14 . The moving mechanism  18  moves the stage  14  linearly in, for example, the width or depth direction of the molding apparatus. In other words, the moving mechanism  18  moves the discharge part  50  relative to the stage  14  linearly in the width or depth direction of the molding apparatus. 
     The moving mechanism  18  can move the stage  14  to a desired position in the width and the depth directions of the molding apparatus. Hence, the moving mechanism  18  can move the discharge part  50  relative to the stage  14  linearly in a direction at an angle to the width and the depth directions of the molding apparatus. 
     The moving mechanism  18  can also move the discharge part  50  relative to the stage  14  in a curve. The moving mechanism  18  can move the discharge part  50  relative to the stage  14  in a curve in the clockwise or counterclockwise direction. 
     The clockwise and the counterclockwise directions are the directions as seen in plan view, and the clockwise direction is an example first curve direction, and the counterclockwise direction is an example second curve direction, which is opposite to the first curve direction. It is also possible to define the clockwise direction as an example second curve direction and the counterclockwise direction as an example first curve direction. It is also possible to enable a direction change in the middle of continuous direction changes. 
     The moving mechanism  18  can move the discharge part  50  relative to the stage  14  in a curve with a desired radius of curvature. Accordingly, the moving mechanism  18  can move the discharge part  50  relative to the stage  14  in a curve with a first radius of curvature or a second radius of curvature, which is smaller than the first radius of curvature, according to the layer data. 
     As described above, the moving mechanism  18  relatively moves the discharge part  50  linearly. As a result, the molding material  100  can be molded in a linear shape in the moving direction of the discharge part  50 . In addition, as described above, the moving mechanism  18  relatively moves the discharge part  50  in a curve. As a result, the molding material  100  can be molded in a curved shape in the moving direction of the discharge part  50 . 
     The moving mechanism  18  can move the stage  14  also in the height direction of the molding apparatus. As a result of the moving mechanism  18  moving the stage  14  in the height direction of the molding apparatus, the distance between the receiving surface  14 A of the stage  14  and the discharge part  50  is adjusted. The moving mechanism  18  may be, for example, a triaxial robot that can move the stage  14  to a desired position in the height, width, and depth directions of the molding apparatus. This allows the stage  14  to rotate or move in a zig-zag manner in accordance with the rotation of the discharge part  50 , enabling partial molding in which a shape having no overlapping part, such as a serpentine shape, is formed. 
     Molding Unit 
     The molding unit  12  shown in  FIG. 1  is a discharging mechanism that discharges the molding material  100  on the stage  14 . The molding unit  12  includes a support body  60 , a feeding mechanism  20 , a transport unit  40 , the discharge part  50 , a rotation mechanism  62 , a pressure roller  56 , a detection sensor  57 , an ejecting head  59 , and a pressure roller  58 . 
     Support Body 
     The support body  60  supports components of the feeding mechanism  20 , the transport unit  40 , the discharge part  50 , etc. The support body  60  supports the discharge part  50  so as to allow rotation about the vertical axis. 
     Feeding Mechanism 
     The feeding mechanism  20  feeds the wire-shaped molding material  100 , which is formed of the fiber bundle  110  impregnated with the resin  112 . The feeding mechanism  20  includes a feeding part  21 , a guide roller  22 , and an impregnating unit  24 . 
     Feeding Part 
     The feeding part  21  feeds the fiber bundle  110  to the guide roller  22 . The feeding part  21  includes a reel around which the fiber bundle  110  is wound. The feeding part  21  is supported by the support body  60  so as to be rotatable. 
     The feeding part  21  feeds the fiber bundle  110  in the width direction of the molding apparatus (to the left side in  FIG. 1 ) by rotating counterclockwise in  FIG. 1 . 
     The fiber bundle  110  is a bundle of multiple untwisted continuous fibers  120 . In this exemplary embodiment, for example, the continuous fibers  120  are carbon fibers having a diameter of 0.005 mm, and 1000 or more continuous fibers  120  are bundled together into the fiber bundle  110 . As shown in  FIG. 2 , the fiber bundle  110  has a circular cross section having a diameter (Dl in  FIG. 2 ) of 0.3 mm to 0.4 mm.  FIG. 2  shows the cross section in which the number of fibers is reduced. 
     Guide Roller 
     As shown in  FIG. 1 , the guide roller  22  is disposed on one side (the left side in  FIG. 1 ) of the feeding part  21  in the width direction of the molding apparatus and is supported by the support body  60  so as to be rotatable. The guide roller  22  supports the fiber bundle  110  fed out of the feeding part  21 . 
     The fiber bundle  110  fed out of the feeding part  21  in the width direction of the molding apparatus runs on the guide roller  22  and is guided downward. Hence, the guide roller  22  guides the fiber bundle  110  downward. 
     Impregnating Unit 
     The impregnating unit  24  impregnates the fiber bundle  110  with the resin to produce the wire-shaped molding material  100 . As shown in  FIG. 1 , the impregnating unit  24  is disposed downstream of the guide roller  22  in a feed direction in which the molding material  100  is fed from the feeding part  21 . More specifically, the impregnating unit  24  is disposed below the guide roller  22 . 
     The impregnating unit  24  includes a passage  26 , through which the fiber bundle  110  passes, and a resin supply part  28  that supplies resin to the passage  26 . 
     The resin supply part  28  stores the resin therein. The resin supply part  28  includes a heater  28 A for heating the resin stored therein, and a screw  28 B for supplying the heated resin to the passage  26 . In this exemplary embodiment, for example, the resin stored in the resin supply part  28  is polypropylene resin. The heater  28 A heats the stored polypropylene resin to, for example, 180° C. to 300° C. to melt. 
     The passage  26  allows the fiber bundle  110  fed out of the feeding part  21  to pass therethrough. The passage  26  has a vertically extending cylindrical shape. The passage  26  includes: a receiving port  26 A from which the fiber bundle  110  fed out of the feeding part  21  is received; a cylindrical reservoir  26 B in which the resin is reserved so as to surround, from the circumferential direction, the fiber bundle  110  passing therethrough; a discharging head  26 C from which the molding material  100 , which is the fiber bundle  110  impregnated with the resin, is discharged; and a heater  26 D attached to the surrounding wall to heat the resin in the reservoir  26 B. The receiving port  26 A, the reservoir  26 B, and the discharging head  26 C are arranged in this order from above to below. In this exemplary embodiment, for example, the heater  26 D heats the polypropylene resin reserved in the reservoir  26 B to 200° C. to 300° C. 
     In the impregnating unit  24 , the resin supply part  28  supplies heated resin to the reservoir  26 B of the passage  26 . In the passage  26 , the fiber bundle  110  entering from the receiving port  26 A and passing through the reservoir  26 B is impregnated with the resin. The wire-shaped molding material  100 , which is the fiber bundle  110  impregnated with the resin, is discharged from the discharging head  26 C of the passage  26 . As shown in  FIG. 3 , the spaces between the fibers constituting the molding material  100  discharged from the discharging head  26 C are filled with the resin, and the molding material  100  has a circular cross section having a diameter of 0.3 mm to 0.4 mm.  FIG. 3  shows the cross section in which the number of fibers is reduced. 
     Impregnating the fiber bundle  110  with the resin bonds the fibers together. Hence, the impregnating unit  24  serves as a bonding unit that bonds the fibers together. 
     Transport Unit 
     The transport unit  40  transports the molding material  100  supplied from the feeding mechanism  20  to the discharge part  50 . As shown in  FIG. 1 , the transport unit  40  is disposed downstream of the impregnating unit  24  in the feed direction in which the feeding part  21  feeds the molding material  100 . The transport unit  40  is disposed below the impregnating unit  24 . 
     The transport unit  40  includes, for example, a pair of transport rollers,  42  and  44 . The transport roller  44  is disposed opposite the transport roller  42  with the molding material  100  therebetween. 
     The transport rollers  42  and  44  are supported by the support body  60  so as to be rotatable. The transport rollers  42  and  44  rotate in the circumferential direction by receiving a driving force from a driving unit (not shown). In the transport unit  40 , the rotating transport rollers  42  and  44  transport the molding material  100  nipped therebetween at a speed of, for example, 30 mm/s. The transport speed of the molding material  100  is not limited to 30 mm/s. 
     The molding material  100  having a circular cross section may be nipped and pressed between the transport rollers  42  and  44  in the transport unit  40  so as to be deformed to have a flat cross section. As shown in  FIG. 4 , in a flat cross section, the length of the sides extending in one direction is larger than the length of the sides extending in a direction intersecting the one direction, and a pair of planes (hereinbelow “flat planes  100 D”) perpendicular to the intersecting direction are formed. In other words, the flat planes  100 D are a pair of planes perpendicular to the transverse direction of the flat shape. 
     The transport rollers  42  and  44  may have a heating portion for heating the molding material  100 . The transport unit  40  may have transport belts, instead of the transport rollers. 
     Discharge Part 
     As shown in  FIG. 1 , the discharge part  50  discharges the molding material  100  on the stage  14 . The discharge part  50  is disposed downstream of the transport unit  40  in the feed direction, in which the molding material  100  is fed out from the feeding part  21 . The discharge part  50  is disposed below the transport unit  40 . 
     The discharge part  50  has an inflow port  50 C through which the molding material  100  transported by the transport unit  40  is introduced, and a discharge port  50 B through which the molding material  100  entering from the inflow port  50 C is discharged onto the receiving surface  14 A of the stage  14 . The discharge part  50  may have a heating portion for heating the molding material  100 . 
     Rotation Mechanism 
     The rotation mechanism  62  shown in  FIG. 1  rotates the discharge part  50 . The rotation mechanism  62  rotates the discharge part  50  about the vertical axis. The rotation mechanism  62  positively and negatively rotates the discharge part  50  about the axis perpendicular to the receiving surface  14 A of the stage  14 . 
     The rotation mechanism  62  rotates the discharge part  50  to spirally twist the molding material  100  discharged from the discharge part  50 . When the discharge part  50  is moved in a curve with respect to the stage  14  to form the molding material  100  in a curved shape, the rotation mechanism  62  rotates the discharge part  50  in the same direction as the direction in which the discharge part  50  is moved in a curve relative to the stage  14  to spirally twist the molding material  100 , being formed in a curved shape, as being discharged from the discharge part  50 . 
     More specifically, when the discharge part  50  is moved in the clockwise direction relative to the stage  14 , the rotation mechanism  62  positively rotates the discharge part  50  in the clockwise direction, whereas, when the discharge part  50  is moved in the counterclockwise direction relative to the stage  14 , the rotation mechanism  62  negatively rotates the discharge part  50  in the counterclockwise direction. The clockwise and the counterclockwise directions are the directions as seen in plan view. 
     In addition, the rotation mechanism  62  can adjust the number of rotations (rotational number) of the discharge part  50 . The number of rotations of the discharge part  50  is the number by which the discharge part  50  rotates per unit time. 
     In this exemplary embodiment, the rotation mechanism  62  rotates the discharge part  50  by a first rotational number when the discharge part  50  is relatively moved linearly and rotates the discharge part  50  by a second rotational number, which is greater than the first rotational number, when the discharge part  50  is relatively moved in a curve. 
     More specifically, the rotation mechanism  62  rotates the discharge part  50  by the second rotational number when the discharge part  50  is relatively moved in a curve with the first radius of curvature and rotates the discharge part  50  by a third rotational number, which is greater than the second rotational number, when the discharge part  50  is relatively moved in a curve with the second radius of curvature, which is smaller than the first radius of curvature. The rotation mechanism  62  rotates the discharge part  50  by the second rotational number when the discharge part  50  is relatively moved in a curve with the first radius of curvature or more, and rotates the discharge part  50  by the third rotational number, which is greater than the second rotational number, when the discharge part  50  is relatively moved in a curve with a radius of curvature that is smaller than the first radius of curvature. It is desirable that the rotational number of the discharge part  50  gradually increase as the radius of curvature employed when the discharge part  50  is relatively moved decreases. 
     Pressure Roller 
     The pressure roller  56  shown in  FIG. 1  is an example pressure part. The pressure roller  56  presses the molding material  100  discharged from the discharge part  50 . The pressure roller  56  applies pressure by pressing the molding material  100  against the receiving surface  14 A of the stage  14 , thus sandwiching the molding material  100  between the pressure roller  56  and the stage  14 . As a result of the pressure roller  56  pressing the molding material  100 , variation in height among portions of the molding material  100  discharged on the stage  14  is reduced. 
     The pressure roller  56  may have a heating portion for heating the molding material  100 . The heating portion may be, for example, a heating source provided inside the pressure roller  56 . In addition, the heating portion may be a heating device that heats the pressure roller  56  from outside. Examples of the heating source and the heating device include heaters using a heating wire, a halogen lamp, and a laser. 
     Detection Sensor 
     The detection sensor  57  shown in  FIG. 1  detects the height of the molding material  100  that has been discharged from the discharge part  50  on the stage  14  and pressed by the pressure roller  56 . The detection sensor  57  is disposed downstream of the pressure roller  56  in the discharge direction in which the molding material  100  is discharged. The detection sensor  57  is, for example, a reflection light sensor. For example, the detection sensor  57  emits light onto the molding material  100  discharged from the discharge part  50  on the stage  14  and pressed by the pressure roller  56  and receives the reflected light. 
     Discharge Head 
     The ejecting head  59  shown in  FIG. 1  is an example ejecting part. When the difference in height among portions of the molding material  100  discharged from the discharge part  50  on the stage  14  and pressed by the pressure roller  56  is greater than or equal to a predetermined threshold, the ejecting head  59  ejects resin onto the molding material  100 . The ejecting head  59  ejects the same type of resin as the resin with which the fiber bundle  110  is impregnated in the impregnating unit  24 . The difference in height among portions of the molding material  100  is detected by a detecting unit  17  described below. 
     Pressure Roller 
     The pressure roller  58  shown in  FIG. 1  serves as another pressure part that presses the molding material  100  onto which the resin has been discharged from the ejecting head  59 . The pressure roller  58  applies pressure to the molding material by pressing the molding material  100  against the receiving surface  14 A of the stage  14 , sandwiching the molding material  100  between the pressure roller  58  and the stage  14 . As a result of the pressure roller  58  applying pressure to the molding material  100 , the variation in height among the portions of the molding material  100  is reduced. In addition, gaps and irregularities caused by the difference in spiral state at a linear portion and a curved portion can be minimized. 
     Similarly to the pressure roller  56 , the pressure roller  58  may also have a heating portion for heating the molding material  100 . The heating portion may be, for example, a heating source provided inside the pressure roller  58 . The heating portion may alternatively be a heating device that heats the pressure roller  58  from outside. Examples of the heating source and the heating device include heaters using a heating wire, a halogen lamp, and a laser. 
     Control Unit 
     The control unit  16  shown in  FIG. 1  controls the operations of the respective components of the molding apparatus  10 . The control unit  16  includes a read-only memory (ROM) storing a program, a storage unit composed of a storage or the like, and a processor that operates according to the program. The control unit  16  controls the operations of the respective components of the molding apparatus  10  by reading and executing the program stored in the storage unit. 
     As shown in  FIG. 5 , the control unit  16  includes, as functional components: the detecting unit  17 ; a moving mechanism controller  16 A that controls the operation of the moving mechanism  18 ; an impregnating unit controller  16 B that controls the operation of the impregnating unit  24 ; a transport unit controller  16 C that controls the operation of the transport unit  40 ; a rotation mechanism controller  16 D that controls the operation of the rotation mechanism  62 ; and an ejecting head controller  16 E that controls the operation of the ejecting head  59 . The impregnating unit controller  16 B controls the operation of the heater  28 A, the screw  28 B, and the heater  26 D of the impregnating unit  24 . 
     The detecting unit  17  detects the heights of portions of the molding material  100  discharged from the discharge part  50  on the stage  14  and pressed by the pressure roller  56 , as well as the difference in height among these portions, on the basis of the detection result obtained by the detection sensor  57 . The detecting unit  17  obtains the heights of portions of the molding material  100  on the basis of the reflection time, which is the time elapsed from when the detection sensor  57  emits light to when the detection sensor  57  receives the reflected light. In addition, the detecting unit  17  detects the difference in height among portions from the obtained heights of the portions. More specifically, for example, the difference between the maximum height and the minimum height of the portions within a predetermined area of the molding material  100  is regarded as the difference in height among portions. 
     The ejecting head controller  16 E determines if the difference in height detected by the detecting unit  17  is greater than or equal to a predetermined threshold, and, when it is determined that the difference in height is greater than or equal to the predetermined threshold, causes the ejecting head  59  to discharge resin. 
     More specifically, the control unit  16  controls the operations of the moving mechanism  18 , the feeding mechanism  20 , the transport unit  40 , the rotation mechanism  62 , the ejecting head  59 , and the like such that the molding operation described below is performed according to the layer data about multiple layers generated from the three-dimensional data of the article to be molded. 
     Molding Operation of Molding Apparatus 
     A molding operation of molding an article  200  including a linear portion and a curved portion according to the layer data about multiple layers generated from the three-dimensional data of the article to be molded will be described. More specifically, a molding operation of molding the article  200 , which includes linear portions  201  and  206  and curved portions  202 ,  203 ,  204 , and  205 , as shown in  FIG. 6 , according to the layer data will be described. 
     The curved portions  202  and  203  are curved in the clockwise direction, whereas the curved portions  204  and  205  are curved in the counterclockwise direction. In other words, the direction in which the spiral is curved in the curved portions  202  and  203  and the direction in which the spiral is curved in the curved portions  204  and  205  are different. Compared with the case where the directions in which the spiral is curved are the same, the twisting of the fibers occurring in changing direction and the residual strain therein are reduced. 
     In addition, the curved portion  203  has a smaller radius of curvature than the curved portion  202 . The curved portion  204  has a smaller radius of curvature than the curved portion  205 . The curved portion  202  and the curved portion  205  have the same radius of curvature. The curved portion  203  and the curved portion  204  have the same radius of curvature. In  FIG. 6 , reference signs  202 S,  203 S,  204 S and  205 S denote the centers of curvature of the curved portions  202 ,  203 ,  204  and  205 . 
     When the article  200  having the linear portions  201  and  206  and the curved portions  202 ,  203 ,  204  and  205  is molded, the moving mechanism  18  moves the stage  14  to move the molding unit  12  including the discharge part  50  relative to the stage  14  in the following manner. 
     As shown in  FIG. 7 , first, the discharge part  50  is relatively moved linearly in a first direction M 1 , (hereinbelow, this movement will be referred to as “linear movement A”). Next, the discharge part  50  is relatively moved in a curve in a clockwise direction M 2  with a first radius of curvature R 1  (hereinbelow, this movement will be referred to as “curved movement B”). Then, the discharge part  50  is relatively moved in a curve in a clockwise direction M 3  with a second radius of curvature R 2  (hereinbelow, this movement will be referred to as “curved movement C”). Then, the discharge part  50  is relatively moved in a curve in a counterclockwise direction M 4  with the second radius of curvature R 2  (hereinbelow, this movement will be referred to as “curved movement D”). Then, the discharge part  50  is relatively moved in a curve in a counterclockwise direction M 5  with the first radius of curvature R 1  (hereinbelow, this movement will be referred to as “curved movement E”). Then, the discharge part  50  is relatively moved linearly in a second direction M 6  (hereinbelow, this movement will be referred to as “linear movement F”). The first direction M 1  is, for example, the width direction W of the molding apparatus, as shown in  FIG. 1 . The clockwise and the counterclockwise directions are the directions as seen in plan view.  FIG. 7  shows the locus of the center  50 S of the discharge port  50 B of the discharge part  50  in plan view. 
     In this exemplary embodiment, when the molding material  100  is discharged from the discharge part  50 , the rotation mechanism  62  rotates the discharge part  50 , allowing the molding material  100  to be discharged from the discharge part  50  while being spirally twisted. 
     More specifically, in the linear movement A, the rotation mechanism  62  rotates the discharge part  50  by a predetermined first rotational number, allowing the molding material  100  to be discharged from the discharge part  50  while being spirally twisted. At this time, the rotation mechanism  62  rotates the discharge part  50  in, for example, the clockwise direction. 
     Next, in the curved movement B, the rotation mechanism  62  rotates the discharge part  50  in the clockwise direction by the second rotational number, which is greater than the first rotational number, allowing the molding material  100  to be discharged from the discharge part  50  while being spirally twisted. 
     Next, in the curved movement C, the rotation mechanism  62  rotates the discharge part  50  in the clockwise direction by the third rotational number, which is greater than the second rotational number, allowing the molding material  100  to be discharged from the discharge part  50  while being spirally twisted. 
     Then, in the curved movement D, the rotation mechanism  62  rotates the discharge part  50  in the counterclockwise direction by the third rotational number, allowing the molding material  100  to be discharged from the discharge part  50  while being spirally twisted. 
     Then, in the curved movement E, the rotation mechanism  62  rotates the discharge part  50  in the counterclockwise direction by the second rotational number, allowing the molding material  100  to be discharged from the discharge part  50  while being spirally twisted. 
     Then, in the linear movement F, the rotation mechanism  62  rotates the discharge part  50  by the first rotational number, allowing the molding material  100  to be discharged from the discharge part  50  while being spirally twisted. At this time, the rotation mechanism  62  rotates the discharge part  50  in, for example, the counterclockwise direction. 
     As shown in  FIG. 1 , the molding material  100  discharged from the discharge part  50  on the stage  14  is pressed by the pressure roller  56 . This reduces variation in height among portions of the molding material  100  discharged on the stage  14 . 
     In addition, in this exemplary embodiment, the detecting unit  17  detects the difference in height among portions of the molding material  100  pressed by the pressure roller  56 , on the basis of the detection result obtained by the detection sensor  57 . 
     The ejecting head controller  16 E determines whether the difference in height detected by the detecting unit  17  is greater than or equal to the predetermined threshold and, if it is determined that the difference in height is higher than or equal to the predetermined threshold, causes the ejecting head  59  to discharge resin. 
     The molding material  100  onto which the resin has been discharged from the ejecting head  59  is pressed by the pressure roller  58 . This reduces the variation in height among the portions of the molding material  100 . 
     As described above, in this exemplary embodiment, the rotation mechanism  62  rotates the discharge part  50 , allowing the molding material  100  to be discharged from the discharge part  50  while being spirally twisted. 
     Hence, compared with a configuration in which the fiber bundle  110  is spirally twisted and is then impregnated with the resin  112 , buckling, breakage, and folding back of the continuous fibers  120  are reduced, and thus, decrease in strength of the molding material  100  is suppressed. In particular, buckling and breakage of the continuous fibers  120  occurring at the curved portions  202 ,  203 ,  204  and  205  of the article  200  are reduced, thus suppressing decrease in strength of the molding material  100 . 
     In this exemplary embodiment, when the discharge part  50  is moved in a curve relative to the stage  14  to form a curved shape with the molding material  100 , the rotation mechanism  62  rotates the discharge part  50  in the same direction as the direction in which the discharge part  50  is moved in a curve relative to the stage  14 , allowing the molding material  100 , which is formed in a curved shape, to be discharged from the discharge part  50  while being spirally twisted. 
     Hence, compared with a configuration in which the rotation mechanism  62  rotates the discharge part  50  in the direction opposite to the direction in which the discharge part  50  is moved in a curve to spirally twist the molding material  100 , fracture of the molding material  100  occurring at a curved portion is suppressed. 
     In this exemplary embodiment, the rotation mechanism  62  positively rotates the discharge part  50  in the clockwise direction when the discharge part  50  is relatively moved in the clockwise direction, and the rotation mechanism  62  negatively rotates the discharge part  50  in the counterclockwise direction when the discharge part  50  is relatively moved in the counterclockwise direction. 
     Hence, compared with a configuration in which the discharge part  50  is rotated in the same direction regardless of the direction in which the discharge part  50  is moved in a curve, fracture of the molding material  100  at a curved portion is suppressed. In addition, in this configuration, the spiral direction of the molding material  100  is controlled according to the direction in which the discharge part  50  is moved in a curve. Hence, the load applied to the continuous fibers  120  and the internal strain are reduced, thus enabling continuous molding. 
     In this exemplary embodiment, the rotation mechanism  62  rotates the discharge part  50  by the first rotational number when the discharge part  50  is relatively moved linearly, and rotates the discharge part  50  by the second rotational number, which is greater than the first rotational number, when the discharge part  50  is relatively moved in a curve. 
     Hence, compared with a configuration in which the rotational number of the discharge part  50  is constant regardless of whether the discharge part  50  is moved linearly or in a curve, fracture of the molding material  100  occurring at a curved portion is suppressed. 
     In this exemplary embodiment, the rotation mechanism  62  rotates the discharge part by the second rotational number when the discharge part  50  is relatively moved in a curve with the first radius of curvature, and rotates the discharge part  50  by the third rotational number, which is greater than the second rotational number, when the discharge part  50  is relatively moved in a curve with the second radius of curvature. 
     This configuration reduces fracture of the molding material  100  occurring at a curved portion, compared with a configuration in which the rotational number of the discharge part  50  is constant regardless of the radius of curvature with which the discharge part  50  is relatively moved in a curve. 
     In this exemplary embodiment, the ejecting head  59  ejects resin onto the molding material  100  when the difference in height among portions of the molding material  100  discharged from the discharge part  50  on the stage  14  is greater than or equal to the predetermined threshold (for example, in the case where the layer thickness is 100 μm, a difference within about 10% of the layer thickness is allowed). 
     Hence, compared with a configuration in which an article is molded from the molding material  100  in a state of just being discharged on the stage  14 , steps (more specifically, for example, steps produced by stacking the continuous fibers  120 ) between portions of the molding material  100  discharged on the stage  14  are reduced. 
     In this exemplary embodiment, the pressure roller  56  presses the molding material  100  discharged from the discharge part  50 , and, when the difference in height among portions of the molding material  100  pressed by the pressure roller  56  is greater than or equal to the predetermined threshold, resin is discharged onto the molding material  100 . 
     Hence, compared with a configuration in which an article is molded from the molding material  100  in a state of just being discharged on the stage  14 , the amount of resin needed to eliminate the steps (more specifically, for example, steps produced by stacking the continuous fibers  120 ) between portions of the molding material  100  discharged on the stage  14  is reduced. 
     Modifications 
     In this exemplary embodiment, the rotation mechanism  62  rotates the discharge part by the second rotational number when the discharge part  50  is relatively moved in a curve with the first radius of curvature, and rotates the discharge part  50  by the third rotational number, which is greater than the second rotational number, when the discharge part  50  is relatively moved in a curve with the second radius of curvature. However, other configurations are also possible. 
     For example, the rotation mechanism  62  may rotate the discharge part  50  by the first rotational number when the discharge part  50  is relatively moved in a curve with the first radius of curvature, and may rotate the discharge part  50  by the second rotational number when the discharge part  50  is relatively moved in a curve with the second radius of curvature. In other words, when the discharge part  50  is relatively moved in a curve with the first radius of curvature, the rotation mechanism  62  may rotate the discharge part  50  by the same rotational number as the rotational number employed when the discharge part  50  is relatively moved linearly. 
     This configuration reduces fracture of the molding material  100  occurring at a curved portion, compared with a configuration in which the rotational number of the discharge part  50  is constant regardless of the radius of curvature employed when the discharge part  50  is relatively moved in a curve. 
     In this exemplary embodiment, when the discharge part  50  is moved in a curve relative to the stage  14  to allow the molding material  100  to be molded in a curved shape, the rotation mechanism  62  rotates the discharge part  50  in the same direction as the direction in which the discharge part  50  is moved in a curve relative to the stage  14  to spirally twist the molding material  100 , to be molded in a curved shape, being discharged from the discharge part  50 . However, other configurations are also possible. For example, the rotation mechanism  62  may rotate the discharge part  50  in the direction opposite to the direction in which the discharge part  50  is moved in a curve to spirally twist the molding material  100 . 
     In this exemplary embodiment, the rotation mechanism  62  positively rotates the discharge part  50  in the clockwise direction when the discharge part  50  is relatively moved in the clockwise direction, and the rotation mechanism  62  negatively rotates the discharge part  50  in the counterclockwise direction when the discharge part  50  is relatively moved in the counterclockwise direction. However, other configurations are also possible. For example, the rotation direction of the discharge part  50  may be constant regardless of the direction in which the discharge part  50  is moved in a curve. 
     In this exemplary embodiment, the rotation mechanism  62  rotates the discharge part  50  by the first rotational number when the discharge part  50  is relatively moved linearly, and rotates the discharge part  50  by the second rotational number, which is greater than the first rotational number, when the discharge part  50  is relatively moved in a curve. However, other configurations are also possible. For example, the rotational number of the discharge part  50  may be constant regardless of whether the discharge part  50  is relatively moved linearly or in a curve. 
     In this exemplary embodiment, the rotation mechanism  62  rotates the discharge part by the second rotational number when the discharge part  50  is relatively moved in a curve with the first radius of curvature, and rotates the discharge part  50  by the third rotational number, which is greater than the second rotational number, when the discharge part  50  is relatively moved in a curve with the second radius of curvature. However. However, other configurations are also possible. For example, the rotational number of the discharge part  50  may be constant (more specifically, the second rotational number may be employed) regardless of the radius of curvature employed when the discharge part  50  is relatively moved. 
     In this exemplary embodiment, the ejecting head  59  ejects resin onto the molding material  100  when the difference in height among portions of the molding material  100  discharged from the discharge part  50  on the stage  14  is greater than or equal to the predetermined threshold. However, other configurations are also possible. For example, the ejecting head  59  may be omitted, and the molding material  100  in a state of just being discharged on the stage  14  may be used to mold an article. 
     In this exemplary embodiment, the ejecting head controller  16 E determines whether the difference in height detected by the detecting unit  17  is greater than or equal to a predetermined threshold and, when it is determined that the difference in height is greater than or equal to the predetermined threshold, causes the ejecting head  59  to discharge resin. However, other configurations are also possible. For example, the ejecting head  59  may be caused to eject the resin when the difference in height among portions of the molding material  100  relative to the predetermined reference value (for example, the height of the stage  14 ) is less than or equal to a predetermined threshold. 
     The present disclosure is not limited to the above-described exemplary embodiment, and various modifications, changes, improvements are possible within the scope not departing from the spirit thereof. For example, the above-described modifications may be combined with one or more other modifications where appropriate. 
     The foregoing description of the exemplary embodiment of the present disclosure has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiment was chosen and described in order to best explain the principles of the disclosure and its practical applications, thereby enabling others skilled in the art to understand the disclosure for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the disclosure be defined by the following claims and their equivalents.