A plasticizing device includes: a material storage unit having a charging port and configured to store pellet-shaped resin pellets; a plasticizing unit having a supply port in communication with the charging port and configured to plasticize at least a part of the resin pellets to generate a shaping material; a coupling pipe having a coupling path coupling the charging port and the supply port; a first material sensor configured to detect a remaining quantity of the resin pellets in the coupling path; and a control unit. The material storage unit includes a material supply mechanism configured to supply the resin pellets to the coupling path, and when the remaining quantity of the resin pellets detected by the first material sensor is less than a first reference value, the control unit controls the material supply mechanism to supply a predetermined quantity of the resin pellets to the coupling path.

The present application is based on, and claims priority from JP Application Serial Number 2021-099987, filed Jun. 16, 2021, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a plasticizing device, a three-dimensional shaping apparatus, and an injection molding apparatus.

2. Related Art

A plasticizing device for plasticizing resin pellets, which are pellet-shaped resin materials, is used for a three-dimensional shaping apparatus and an injection molding apparatus that mold a structure using the resin pellets. JP-A-2010-241016 discloses a flat screw-type plasticizing device. The plasticizing device includes a rotor formed with a spiral groove, and a barrel that abuts against an end surface of the rotor and is provided with a communication hole in a center. The rotor and the barrel face each other. The rotor is rotated by a motor. A heater is disposed in the barrel, and the resin pellets are heated and plasticized in the spiral groove.

The resin pellets that are materials are stored in a hopper. The resin pellets are supplied from the hopper to an inlet of the spiral groove provided on a side surface of the rotor.

In the plasticizing device disclosed in JP-A-2010-241016, a bridge phenomenon occurs in which the resin pellets interfere with each other and become clogged due to the weight of the resin pellets themselves until the resin pellets are supplied to the rotor. When the bridge phenomenon occurs, the resin pellets are not properly supplied to the rotor. An object of the present application is to prevent the bridge phenomenon.

SUMMARY

A plasticizing device includes: a material storage unit having a charging port and configured to store a pellet-shaped plasticizing material; a plasticizing unit having a supply port in communication with the charging port and configured to plasticize at least a part of the plasticizing material to generate a shaping material; a coupling pipe having a coupling path coupling the charging port and the supply port; a first material sensor configured to detect a remaining quantity of the plasticizing material in the coupling path; and a control unit. The material storage unit includes a material supply mechanism configured to supply the plasticizing material to the coupling path, and when the remaining quantity detected by the first material sensor is less than a first reference value, the control unit controls the material supply mechanism to supply a predetermined quantity of the plasticizing material to the coupling path.

A three-dimensional shaping apparatus includes: the plasticizing device as described above; a stage having a shaping surface; and a nozzle configured to discharge to the shaping surface the shaping material supplied from the plasticizing device.

An injection molding apparatus includes: the plasticizing device as described above; and a nozzle configured to inject to a mold the shaping material supplied from the plasticizing device.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

First Embodiment

In a first embodiment, a characteristic example of a three-dimensional shaping apparatus including a plasticizing device will be described with reference to the drawings.FIG.1shows arrows along X, Y, and Z directions orthogonal to each other. The X direction and the Y direction are directions defined along a horizontal direction, and the Z direction is a direction defined along a vertical direction. A gravity direction is a Z negative direction.

As shown inFIG.1, a three-dimensional shaping apparatus1includes a base2. XY tables3that are moving units are disposed on the base2. In the XY tables3, a Y table4and an X table5are stacked in this order in a Z positive direction. A stage6is stacked on the XY tables3.

The Y table4includes a Y axis motor4a, a ball screw, a Y axis scale, and the like. The Y table4reciprocates the stage6in the Y direction. The X table includes an X axis motor5a, a ball screw, an X axis scale, and the like. The X table5reciprocates the stage6in the X direction.

The three-dimensional shaping apparatus1includes a control unit7. The control unit7controls movements of the Y table4and the X table5. The control unit7identifies a position of the stage6in the Y direction based on information output by the Y axis scale. The control unit7identifies a position of the stage6in the X direction based on information output by the X axis scale. The control unit7moves the Y table4and the X table5such that a difference between a target position of moving the stage6and a current position is eliminated. The control unit7controls a trajectory of a movement of the stage6by sequentially changing the target position of moving the stage6.

An elevating table8that is a moving unit is disposed on an X negative direction side on the base2. The elevating table8includes a fixed table8aerected on the base2. A rail8bis disposed on a surface of the fixed table8aon an X positive direction side. A movement table8cis disposed on the X positive direction side of the rail8b. The movement table8creciprocates in the Z direction along the rail8b.

A Z axis motor8dis disposed on a Z positive direction side of the fixed table8a. The fixed table8aincludes a ball screw and a Z axis scale inside. Similarly to the Y table4and the X table5, the control unit7controls a trajectory of a movement of the movement table8c. The moving unit includes the XY tables3and the elevating table8.

A unit support portion9is disposed on the X positive direction side of the movement table8c. A shaping unit11is disposed on the X positive direction side of the unit support portion9. The unit support portion9supports the shaping unit11. In the shaping unit11, a material storage unit12, a coupling pipe13, a plasticizing unit14, and a discharge unit15are disposed in this order in the Z negative direction.

The material storage unit12includes a container16having a cavity inside, and a material supply mechanism17. Resin pellets18that are pellet-shaped plasticizing materials are stored inside the container16. The resin pellets18are lumps of resin. A size of the resin pellets is not particularly limited, and in the present embodiment, the size is, for example, in a range of 5 mm to 20 mm. The material storage unit12includes a charging port12ain the material supply mechanism17. The coupling pipe13includes a coupling path13ainside. The material supply mechanism17supplies the resin pellets18to the coupling path13a. The container16includes a third window16band a fourth window16c. The third window16band the fourth window16care made of a transparent material such as glass. The third window16bis disposed on the Z positive direction side of the container16. The fourth window16cis disposed on a Z negative direction side of the container16. A remaining quantity of the resin pellets18in the container16is observed through the third window16band the fourth window16c.

The coupling pipe13is coupled to the charging port12aof the material storage unit12. The resin pellets18move from the inside of the material storage unit12into the coupling pipe13due to a weight thereof. The coupling pipe13is coupled to the plasticizing unit14. The plasticizing unit14has a supply port14ain communication with the charging port12a. The coupling path13acouples the charging port12aand the supply port14a. The resin pellets18are supplied from the coupling pipe13to the plasticizing unit14. The resin pellets18may contain other materials such as metal and ceramic in addition to a thermoplastic material. In addition, when metal powder is contained in the resin pellets, not all of the resin pellets are plasticized in the plasticizing unit, and thus at least a part of the resin pellets are plasticized in the plasticizing unit.

The plasticizing unit14plasticizes at least a part of the resin pellets18. A term “plasticization” is a concept including melting, and is a change from a solid to a state having fluidity. Specifically, for a material that undergoes a glass transition, the plasticization is to raise a temperature of the material to be equal to or higher than a glass transition point. For a material that does not undergo the glass transition, the “plasticization” is to raise the temperature of the material to be equal to or higher than a melting point. The plasticizing unit14plasticizes the resin pellets18to generate a shaping material19. A plasticizing device21includes the material storage unit12, the coupling pipe13, the plasticizing unit14, the control unit7, and the like.

The plasticizing unit14is coupled to the discharge unit15. The discharge unit15includes a nozzle22. A surface of the stage6on the nozzle22side is a shaping surface6a. The stage6has the shaping surface6a. The nozzle22discharges the shaping material19supplied from the plasticizing device21toward the shaping surface6a. The shaping surface6aof the stage6receives the shaping material19discharged from the nozzle22. While the nozzle22discharges the shaping material19, the control unit7drives the XY tables3to move the stage6in the X direction and the Y direction. Accordingly, the three-dimensional shaping apparatus1forms a figure of a predetermined pattern on the stage6. This figure is a figure of a first stage.

Next, the elevating table8moves the shaping unit11by a predetermined distance in the Z positive direction. The three-dimensional shaping apparatus1forms a figure of a second stage superimposed on the figure of the first stage. Further, the three-dimensional shaping apparatus1forms a three-dimensional structure20by sequentially superimposing and forming figures of a third and subsequent stages.

The plasticizing unit14of the plasticizing device21is dispose below the material storage unit12in the gravity direction. The elevating table8moves the plasticizing unit14and the material storage unit12relative to the stage6. The elevating table8moves the material storage unit12in conjunction with movement of the plasticizing unit14.

According to this configuration, since the plasticizing unit14and the material storage unit12are interlocked with each other, the coupling pipe13may not be deformed when the plasticizing unit14and the material storage unit12move. Therefore, the coupling pipe13can be shortened as compared with the case where the coupling pipe13is deformed.

The XY tables3move the shaping surface6ain a direction along the shaping surface6a. The elevating table8moves the plasticizing unit14and the material storage unit12in a direction perpendicular to the shaping surface6a.

According to this configuration, the plasticizing unit14and the material storage unit12move in the gravity direction and in an opposite direction of the gravity direction. Since the plasticizing unit14and the material storage unit12have a large inertia, the plasticizing unit14and the material storage unit12can be moved faster than when they are moved along a plane orthogonal to a gravitational acceleration direction.

A first material sensor23and a second material sensor24are disposed on the plasticizing unit14side of the coupling path13a. The first material sensor23and the second material sensor24detect a remaining quantity of the resin pellets18in the coupling path13a. The second material sensor24is disposed between the first material sensor23and the charging port12a. A method by which the first material sensor23and the second material sensor24detect the resin pellets18is not particularly limited, and in the present embodiment, for example, an optical method is adopted.

The plasticizing device21includes an air blower25between the material storage unit12and the plasticizing unit14. The air blower25is disposed on the unit support portion9. The air blower25moves up and down in conjunction with the plasticizing unit14and the coupling pipe13. The air blower25includes a blower fan26and a blower nozzle27. The blower fan26flows air and blows air to the blower nozzle27. The blow nozzle27faces the first material sensor23. The air blower25blows air from the blower nozzle27toward the first material sensor23.

According to this configuration, the powdered resin pellets18and dust adhering to the first material sensor23can be blown off. Then, it is possible to prevent a decrease in sensitivity of the first material sensor23.

The air blower25may include the blower nozzle that blows air toward the second material sensor24. The powdered resin pellets18and dust adhering to the second material sensor24can be blown off. Then, it is possible to prevent a decrease in sensitivity of the second material sensor24.

The blower fan26includes an ionizer28inside. The ionizer28produces a gas having a positive charge or a negative charge. The charge of the gas may be set to be positive or negative. The ionizer28may also generate the positive charge and the negative charge alternately. The air blower25blows the gas having the charge. According to this configuration, when the powdered resin pellets18and dust adhere to the first material sensor23due to static electricity, the static electricity can be removed to facilitate removal of the powdered resin pellets18and dust.

Next, a structure of the material supply mechanism17will be described with reference toFIGS.2to5.FIG.3is a view ofFIG.2as viewed from an AA line.FIG.5is a view ofFIG.4as viewed from an AA line. As shown inFIGS.2and3, the material supply mechanism17includes a guide case29. An inside of the guide case29is hollow. The guide case29includes a material inlet16aon the container16side. The guide case29includes the charging port12aon the coupling pipe13side.

The guide case29includes a material cutting plate31that is a slide member inside. The material cutting plate31slides in the X direction inside the guide case29and reciprocates. The material cutting plate31has a cutting hole31aas a hole. An air cylinder32as a slide drive unit is disposed on the Z negative direction side of the guide case29. The air cylinder32includes a piston rod32ainside. The piston rod32areciprocates in the X direction. One end of the piston rod32ais fixed to the material cutting plate31. The material cutting plate31is interlocked with the piston rod32a.

The air cylinder32includes a first air pressure port32bon the X negative direction side. The air cylinder32includes a second air pressure port32con the X positive direction side. When compressed air is supplied to the first air pressure port32b, the piston rod32aand the material cutting plate31move to the X positive direction side. When compressed air is supplied to the second air pressure port32c, the piston rod32aand the material cutting plate31move to the X negative direction side.

The control unit7includes a solenoid valve. A pipe for supplying compressed air is coupled to the solenoid valve. The solenoid valve, the first air pressure port32band the second air pressure port32care coupled by the pipe (not shown). The control unit7controls the solenoid valve to supply compressed air to one of the first air pressure port32band the second air pressure port32c. In this way, the control unit7controls a moving direction of the material cutting plate31.

The material supply mechanism17includes the material cutting plate31having the cutting hole31aand the air cylinder32for sliding the material cutting plate31. The air cylinder32drives the material cutting plate31.

A magnet piece32dis disposed on the piston rod32a. The air cylinder32includes a first cylinder sensor32ethat is a third sensor on the first air pressure port32bside. The air cylinder32includes a second cylinder sensor32fthat is the third sensor on the second air pressure port32cside. When the material cutting plate moves to the X negative direction side, the first cylinder sensor32edetects the magnet piece32d. When the material cutting plate31moves to the X positive direction side, the second cylinder sensor32fdetects the magnet piece32d. Therefore, the first cylinder sensor32eand the second cylinder sensor32fdetect whether the material cutting plate31is located on the X negative direction side, the X positive direction side, or a middle point.

A state in which the material cutting plate31is located in the X positive direction is defined as a second state. InFIG.3, the material cutting plate31is hatched by broken lines. In the second state, when viewed from the Z direction, the cutting hole31aand the charging port12aoverlap. A part of the resin pellets18in the cutting hole31ais charged into the coupling pipe13. That is, in the second state, the resin pellets18in the material storage unit12is charged into the coupling pipe13.

The cutting hole31ahas an inclined surface31gon a side surface on the X negative direction side. An angle defined by the inclined surface31gand the X direction is preferably 25 degrees or more and 35 degrees or less. This angle is called a repose angle, and is an angle at which the resin pellets18do not slip on the inclined surface31g. When an angle of the inclined surface31gis the repose angle, the resin pellets18stay in the cutting hole31a, so that the resin pellets18do not continuously flow from the material inlet16ato the charging port12a. Further, it is possible to prevent the resin pellets18from being clogged between the material inlet16aand the inclined surface31g.

As shown inFIGS.4and5, compressed air is supplied from the second air pressure port32cto the air cylinder32. The piston rod32amoves to the X negative direction. The air cylinder32drives the material cutting plate31, and the material cutting plate31moves to the X negative direction. A state in which the material cutting plate31is located in the X negative direction is defined as a first state. InFIG.5, the material cutting plate31is hatched by broken lines. In the first state, when viewed from the Z direction, the cutting hole31aand the charging port12ado not overlap. Therefore, in the first state, the resin pellets18in the material storage unit12are not charged into the coupling pipe13.

In the first state, when viewed from the Z direction, an area where the material inlet16aand the cutting hole31aoverlap is larger than that in the second state. The resin pellets18are discharged, and charged from the material inlet16ainto a hollow portion of the cutting hole31a. The control unit7drives the air cylinder32to switch between the first state and the second state. When the material cutting plate31reciprocates once, a predetermined quantity of resin pellets18are charged from the charging port12ainto the coupling path13a. The control unit7controls the quantity of the resin pellets18charged into the coupling path13aby controlling the number of times the material cutting plate31is reciprocated.

According to this configuration, the resin pellets18are charged into the cutting hole31ain the first state. In the second state, the resin pellets18are charged from the cutting hole31ainto the coupling path13aof the coupling pipe13. Therefore, the material supply mechanism17can have a simple configuration using the air cylinder32or the like.

When the material cutting plate31moves to the X negative direction side, the magnet piece32dapproaches the first cylinder sensor32e. The first cylinder sensor32edetects the magnet piece32d. Therefore, the first cylinder sensor32edetects that the material cutting plate31is located on the X negative direction side.

The material supply mechanism17includes the first cylinder sensor32eand the second cylinder sensor32fthat detect biting of the resin pellets18of the material cutting plate31. When the material cutting plate31moves to the X negative direction side, the resin pellets are sandwiched between a side surface of the cutting hole31aand a side surface of the charging port12a, which is called biting. When the biting occurs, the first cylinder sensor32edoes not detect the magnet piece32d. When the first cylinder sensor32edoes not detect the magnet piece32d, the control unit7determines that the biting occurs. Then, the control unit7drives the air cylinder32to reciprocate and slide the material cutting plate31. In this way, when the first cylinder sensor32edetects the biting of the resin pellets18, the air cylinder32performs a returning operation of sliding the material cutting plate31.

When the material cutting plate31moves to the X positive direction side, the resin pellets18are sandwiched between the side surface of the cutting hole31aand a side surface of the material inlet16a, which is also called biting. When the biting occurs, the second cylinder sensor32fdoes not detect the magnet piece32d. When the second cylinder sensor32fdoes not detect the magnet piece32deven after a lapse of a predetermined time, the control unit7determines that the biting occurs. Then, the control unit7drives the air cylinder32to reciprocate and slide the material cutting plate31. In this way, when the second cylinder sensor32fdetects the biting of the resin pellets18, the air cylinder32performs the returning operation of sliding the material cutting plate31.

According to this configuration, the first cylinder sensor32eand the second cylinder sensor32fdetect the biting of the resin pellets18. Then, the air cylinder32reciprocates and slides the material cutting plate31to eliminate the biting of the resin pellets18. Therefore, the biting of the resin pellets18can be eliminated without intervention of an operator.

As shown inFIG.6, the first material sensor23includes a first light emitting unit23aand a first light receiving unit23bthat face each other in the Y direction. When the quantity of resin pellets18in the coupling pipe13decreases, the resin pellets18disappear from between the first light emitting unit23aand the first light receiving unit23b, so that the first light receiving unit23bdetects light emitted by the first light emitting unit23a. At this time, the remaining quantity of the resin pellets18inside the coupling pipe13is a first reference value. The first material sensor23detects that the remaining quantity of the resin pellets18is less than the first reference value.

When the remaining quantity of the resin pellets18detected by the first material sensor23is less than the first reference value, the control unit7operates the material supply mechanism17to supply a predetermined quantity of the resin pellets18to the coupling path13a.

According to this configuration, the resin pellets18are stored in the material storage unit12. The coupling pipe13is coupled to the material storage unit12. The material supply mechanism17of the material storage unit12supplies the resin pellets18to the coupling pipe13. When the material supply mechanism17is not operated, the resin pellets18are not supplied to the coupling pipe13. The resin pellets18are collected in the coupling path13aof the coupling pipe13. When the resin pellets18move to the plasticizing unit14, the resin pellets18in the coupling path13adecrease. The resin pellets18not used in the plasticizing unit14are left in the coupling path13aof the coupling pipe13. The first material sensor23detects the remaining quantity of the resin pellets18left in the coupling path13a.

When the remaining quantity of the resin pellets18in the coupling path13ais less than the first reference value, the control unit7drives the material supply mechanism17to supply the predetermined quantity of the resin pellets18to the coupling path13aof the coupling pipe13. Therefore, the resin pellets18of the coupling path13aof the coupling pipe13do not exceed a quantity obtained by adding the first reference value and the predetermined quantity. The quantity obtained by adding the first reference value and the predetermined quantity is a quantity at which a bridge phenomenon does not occur. As a result, it is possible to prevent the bridge phenomenon that the resin pellets18interfere with each other and become clogged due to a weight of the resin pellets18themselves.

The coupling pipe13includes a first window33as a transparent member and a second window34as a transparent member. The first window33and the second window34are made of a transparent member such as glass. Therefore, the inside of the coupling pipe13can be visually recognized. In this way, at least a part of the coupling pipe13is made of the transparent member. According to this configuration, the operator can confirm the remaining quantity of the resin pellets18held in the coupling path13a.

As shown inFIG.7, the second material sensor24is disposed between the first material sensor23and the charging port12a. The second material sensor24includes a second light emitting unit24aand a second light receiving unit24bthat face each other in the Y direction. The material supply mechanism17supplies the resin pellets to the coupling path13a, and the resin pellets18gradually increase in the coupling path13a. When the resin pellets18are not present between the second light emitting unit24aand the second light receiving unit24b, the second light receiving unit24bdetects light emitted by the second light emitting unit24a. When the resin pellets18are present between the second light emitting unit24aand the second light receiving unit24b, the second light receiving unit24bdoes not detect the light emitted by the second light emitting unit24a. When the resin pellets18are supplied to the second material sensor24, the remaining quantity of the resin pellets18inside the coupling pipe13is a second reference value. The second material sensor24detects that the remaining quantity of the resin pellets18reached the second reference value.

In the first material sensor23, when the first light receiving unit23bdetects the light emitted by the first light emitting unit23a, the control unit7receives a signal output by the first material sensor23, and determines that the remaining quantity of the resin pellets18decreased from the first reference value. At this time, the resin pellets18did not reach the second material sensor24. In the second material sensor24, the second light receiving unit24bdetects the light emitted by the second light emitting unit24a. The control unit7operates the material supply mechanism17to supply the resin pellets18to the coupling path13a.

In the second material sensor24, when the second light receiving unit24bdoes not detect the light emitted by the second light emitting unit24a, the control unit7receives a signal output by the second material sensor24, and determines that the remaining quantity of the resin pellets18reached the second reference value. The control unit7stops an operation of the material supply mechanism and stops the supply of the resin pellets18to the coupling path13a.

In this way, when the remaining quantity of the resin pellets18detected by the first material sensor23is less than the first reference value, the material supply mechanism17supplies the resin pellets18up to the second reference value detected by the second material sensor24.

Specifically, the control unit7receives a signal from the first material sensor23. The signal indicates that the remaining quantity of the resin pellets is less than the first reference value. Next, the control unit7outputs an instruction signal for supplying the resin pellets18to the material supply mechanism17. Next, the control unit7receives a signal from the second material sensor24that indicates that the resin pellets18were supplied up to the second reference value. Next, the control unit7outputs an instruction signal for stopping the supply of the resin pellets18to the material supply mechanism17. In this way, the control unit7supplies the resin pellets18up to the second reference value in cooperation with the first material sensor23, the second material sensor24, and the material supply mechanism17.

According to this configuration, a quantity obtained by adding a supply quantity and the remaining quantity of the resin pellet18supplied to the coupling path13aby the material supply mechanism17can be set as the second reference value. The second reference value is a quantity at which the bridge phenomenon does not occur. The quantity obtained by adding the supply quantity and the remaining quantity of the resin pellets18stored in the coupling path13acan be added up to the second reference value. Therefore, a supply frequency can be reduced as compared with a case where a small quantity of the resin pellets18is supplied many times.

Even when the resin pellets18are present between the blower nozzle27and the first material sensor23, the air blower25may blow air toward the first material sensor23. The air may be blown continuously or at predetermined intervals.

As shown inFIG.8, the plasticizing unit14includes a screw case35. An inside of the screw case35is hollow. A motor36is disposed on the Z positive direction side of the screw case35. The control unit7controls a rotation angle, a rotation speed, a rotation start timing, and a rotation stop timing of the motor36.

A reduction gear37is coupled to a rotation shaft36aof the motor36. When the rotation shaft36arotates at a high speed, an outer peripheral side of the reduction gear37rotates at a reduced low speed. The outer peripheral side of the reduction gear37, which rotates at the low speed, serves as an output shaft37a. A bearing38is disposed on the outer peripheral side of the reduction gear37. The bearing38is disposed between the screw case35and the reduction gear37. The bearing38rotatably supports the reduction gear37.

A screw support portion39is disposed at the output shaft37aof the reduction gear37. A flat screw41is disposed at the screw support portion39. The flat screw41rotates in synchronization with the output shaft37a. The flat screw41is rotated by the motor36. A screw rotation center41d, which is a rotation center of the flat screw41, is coaxial with a motor rotation center36b, which is a rotation center of the motor36.

As shown inFIGS.8and9, the flat screw41is provided with a groove forming surface41aon which spiral grooves41bare formed. The flat screw41has a substantially cylindrical shape in which a size in a rotation shaft36adirection is smaller than a size in a direction orthogonal to the rotation shaft36adirection. In the shown example, one groove41bcoupled in a spiral shape is provided. The number of the grooves41bis not particularly limited. Although not shown, two or more grooves41bmay be provided.

The screw case35accommodates the reduction gear37, the screw support portion39, and the flat screw41. The screw case35has a supply path35acoupled to the coupling pipe13. The supply path35aextends from the coupling pipe13to the flat screw41. An opening of the supply path35aon a flat screw41side is a passage port35b. The screw case35is provided with the passage port35bthrough which the resin pellets18pass toward the flat screw41.

A barrel42is disposed on a Z negative direction side of the flat screw41. A barrel case43that accommodates the barrel42is disposed on the Z negative direction side of the screw case35. The flat screw41rotates with respect to the barrel42.

As shown inFIGS.8and10, the barrel42has an opposing surface42afacing the groove forming surface41a. A heater44is disposed inside the barrel42at a position facing the grooves41b. The heater44heats the resin pellets18supplied between the groove forming surface41aand the opposing surface42a. The heated resin pellets18are plasticized into the shaping material19. The barrel42is provided with a communication hole45through which the shaping material19obtained by plasticizing the resin pellets18flows.

A plurality of guide grooves46are formed around the communication hole45in the opposing surface42a. One end of each guide groove46is coupled to the communication hole45, and the guide grooves46extend in a spiral shape from the communication hole45toward an outer periphery of the opposing surface42a. Each guide groove46guides the shaping material19to the communication hole45. One end of each guide groove46may not be coupled to the communication hole45, and the guide grooves46may not be formed in the opposing surface42a.

A depth of the grooves41bin the flat screw41is smaller on a side closer to the screw rotation center41dthan on the outer peripheral side. Therefore, a cross-sectional area of the grooves41bis smaller on the side closer to the screw rotation center41dthan on the outer peripheral side. The shaping material19in the grooves41bexerts a high pressure on a screw rotation center41dside and is pushed out to the communication hole45. The flat screw41functions as a pump that moves the shaping material19.

According to this configuration, since the plasticizing unit14includes the flat screw41and the barrel42, a size of the plasticizing unit14can be smaller than a plasticizing unit including an in-line screw.

According to this configuration, the three-dimensional shaping apparatus1includes the plasticizing device21. The plasticizing device21can prevent the occurrence of the bridge phenomenon. Therefore, the three-dimensional shaping apparatus1can supply the resin pellets18to the plasticizing unit14for a long time.

Second Embodiment

The present embodiment describes an example of an injection molding apparatus including the plasticizing device21of the first embodiment.

As shown inFIG.11, an injection molding apparatus50includes a plasticizing device51, an injection control mechanism52, a nozzle53, a mold54, and a mold clamping device55. The plasticizing device21of the first embodiment is used for the plasticizing device51.

The plasticizing device51includes a flat screw56and a barrel57. An injection cylinder59is coupled to a communication hole58of the barrel57. Under control of a control unit61, the plasticizing device51plasticizes the resin pellets18supplied to groove portions62of the flat screw56, generates the pasty shaping material19having fluidity, and guides the shaping material19from the communication hole58to the injection control mechanism52.

In addition, the plasticizing device51includes a material storage unit69, a coupling pipe71, and an air blower72. The material storage unit69, the coupling pipe71, and the air blower72correspond to the material storage unit12, the coupling pipe13, and the air blower25of the first embodiment, respectively.

The injection control mechanism52includes the injection cylinder59, a plunger63, and a plunger drive unit64. The injection control mechanism52injects the shaping material19in the injection cylinder59into a cavity65. The injection control mechanism52controls an injection quantity of the shaping material19injected from the nozzle53under the control of the control unit61. The injection cylinder59is a substantially cylindrical member coupled to the communication hole58of the barrel57, and includes the plunger63inside. The plunger63slides inside the injection cylinder59, and pumps the shaping material19in the injection cylinder59to the nozzle53coupled to the plasticizing device51. The plunger63is driven by the plunger drive unit64constituted by the motor.

The mold54includes a movable mold66and a fixed mold67. The movable mold66and the fixed mold67face each other, so that the cavity65, which is a space corresponding to a shape of a molded product, is defined between the movable mold66and the fixed mold67. The shaping material19pumped by the injection control mechanism52is injected into the cavity65through the nozzle53.

The mold clamping device55includes a mold drive unit68. The mold drive unit68opens and closes the movable mold66and the fixed mold67. Under the control of the control unit61, the mold clamping device55drives the mold drive unit68to move the movable mold66to open and close the movable mold66and the fixed mold67.

In the injection molding apparatus50, the plasticizing device21of the first embodiment is used for the plasticizing device51. The injection molding apparatus50includes the nozzle53that injects the shaping material19supplied from the plasticizing device51toward the mold54.

According to this configuration, the injection molding apparatus50includes the plasticizing device21as the plasticizing device51. The plasticizing device21can prevent the occurrence of the bridge phenomenon of the resin pellets18. Therefore, the plasticizing device51can supply the shaping material19to the nozzle53for a long time.

Third Embodiment

In the first embodiment, the XY tables3move the stage6in the X direction and the Y direction. The elevating table8moves the discharge unit15in the Z direction. In addition, an elevating table that moves the stage6in the Z direction and XY tables that move the discharge unit15in the X direction and the Y direction may be provided. Further, the stage6may be provided with XYZ tables that do not move or move the discharge unit15in the X direction, the Y direction, and the Z direction. Furthermore, the discharge unit15may be provided with XYZ tables that do not move or move the stage6in the X direction, the Y direction, and the Z direction. In any form, the three-dimensional structure20can be formed on the stage6.