A plasticizing device that plasticizes a solid material includes a drive motor, a screw rotated by the drive motor along a rotation axis of the drive motor and having a groove forming surface on which a groove is formed, a barrel having a facing surface facing the groove forming surface and provided with a communication hole in a central portion thereof, and a heating unit configured to heat at least one of the screw and the barrel. A first facing region and a second facing region that is closer to the central portion than the first facing region are provided between the groove forming surface and the facing surface. A second gap between the groove forming surface and the facing surface in the second facing region is larger than a first gap between the groove forming surface and the facing surface in the first facing region.

The present application is based on, and claims priority from JP Application Serial Number 2019-212100, filed Nov. 25, 2019, 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, an injection molding machine, and a three-dimensional shaping apparatus.

2. Related Art

In the related art, various plasticizing devices that plasticize a solid material are used. Among these, a plasticizing device is included, which plasticizes a material while moving the material by rotating a screw (a so-called flat screw) that faces a barrel and that has a substantially flat groove forming surface on which a spiral groove is formed. For example, JP-A-2010-241016 discloses a plasticizing feeder that includes a rotor (flat screw) on which a spiral groove is formed, and a barrel that is provided with a communication hole in a central portion thereof and is provided at a position in contact with an end surface of the rotor.

However, the material may flow backward in a plasticizing device including a flat screw in the related art, such as the flat screw disclosed in JP-A-2010-241016. When the material flows backward, a capacity of supplying the material to the communication hole is reduced. For example, when the plasticizing device is used in an injection molding machine or a three-dimensional shaping apparatus, a supply of the material may be poor.

SUMMARY

An object of the present disclosure is to prevent a material from flowing backward in a plasticizing device that moves the material by rotating a flat screw that faces a barrel and on which a spiral groove is formed.

In order to attain the object described above, a plasticizing device that plasticizes a solid material according to the present disclosure includes a drive motor, a screw rotated along a rotation axis of the drive motor and having a groove forming surface on which a groove is formed, a barrel having a facing surface facing the groove forming surface and provided with a communication hole in a central portion thereof, and a heating unit configured to heat at least one of the screw and the barrel. A first facing region and a second facing region that is closer to the central portion than the first facing region are provided between the groove forming surface and the facing surface. A second gap that is a gap between the groove forming surface and the facing surface in the second facing region is larger than a first gap that is a gap between the groove forming surface and the facing surface in the first facing region.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

First, the present disclosure will be briefly described.

In order to solve the problem described above, according to a first aspect of the present disclosure, a plasticizing device that plasticizes a solid material is provided. The plasticizing device includes a drive motor, a screw rotated along a rotation axis of the drive motor and having a groove forming surface on which a groove is formed, a barrel having a facing surface facing the groove forming surface and provided with a communication hole in a central portion thereof, and a heating unit configured to heat at least one of the screw and the barrel. A first facing region and a second facing region that is closer to the central portion than the first facing region are provided between the groove forming surface and the facing surface. A second gap that is a gap between the groove forming surface and the facing surface in the second facing region is larger than a first gap that is a gap between the groove forming surface and the facing surface in the first facing region.

According to the first aspect, provided between the groove forming surface and the facing surface are the first facing region and the second facing region that is provided at a position closer to a central portion side than a position of the first facing region and in which a gap between the groove forming surface and the facing surface is larger than that in the first facing region. In this manner, by providing the second facing region in which the gap between the groove forming surface and the facing surface is large at a position close to the central portion where the communication hole is provided, a material can be easily concentrated from the first facing region to the second facing region, and the material can be prevented from flowing backward from a second facing region side to a first facing region side.

According to a second aspect of the present disclosure, in the plasticizing device according to the first aspect, the second gap becomes large toward the central portion, and in a cross section along a rotation axis direction that is a direction in which the rotation axis extends, at least one of the groove forming surface and the facing surface corresponding to the first facing region is inclined at a first angle with respect to an intersecting direction intersecting perpendicularly with the rotation axis direction, at least one of the groove forming surface and the facing surface corresponding to the second facing region is inclined at a second angle with respect to the intersecting direction, and the first angle and the second angle are different angles.

According to the second aspect, since the gap between the groove forming surface and the facing surface in the second facing region becomes large toward the central portion side, in the second facing region, the material is easily concentrated toward the central portion where the communication hole is provided. Therefore, the material can be prevented from flowing backward in the second facing region.

According to a third aspect of the present disclosure, in the plasticizing device according to the second aspect, the second angle is larger than 0° and is 5° or less.

According to the third aspect, an inclination angle in the second facing region is 5° or less, so that the second gap can be prevented from becoming too large. When the second gap is too large, convection may occur in the second facing region, causing the material to flow backward. When the second gap is prevented from becoming too large, a backflow of the material caused by the occurrence of the convection in the second facing region can be prevented.

According to a fourth aspect of the present disclosure, in the plasticizing device according to the second aspect, a boundary between the first facing region and the second facing region in the intersecting direction is at a position satisfies a relationship indicated by the following expression (1)
1/3≤Lb/La≤1/2.5  (1)

(La represents a linear distance from an outer end portion of the groove forming surface or the facing surface to a rotation center of the rotation axis in the intersecting direction, and Lb represents a linear distance from the outer end portion to the boundary in the intersecting direction).

According to the fourth aspect, a ratio of the linear distance from the outer end portion where the screw and the barrel face each other in the intersecting direction to a boundary portion between the first facing region and the second facing region with respect to the linear distance from the outer end portion where the screw and the barrel face each other in the intersecting direction to the rotation center of the screw is 1/3 or more and 1/2.5 or less. When the ratio is too large, it may be difficult to concentrate the material from the first facing region to the second facing region, and when the ratio is too small, it may be difficult to concentrate the material toward the central portion in the second facing region. However, such adverse effects can be prevented by setting the ratio to 1/3 or more and 1/2.5 or less.

According to a fifth aspect of the present disclosure, in the plasticizing device according to the second aspect, the facing surface has a first facing surface located in the first facing region and a second facing surface located in the second facing region, and the first facing surface is inclined at the first angle and the second facing surface is inclined at the second angle.

According to the fifth aspect, the first facing surface and the second facing surface are formed on the facing surface, so that the first facing region and the second facing region can be formed.

According to a sixth aspect of the present disclosure, in the plasticizing device according to the fifth aspect, in the cross section along the rotation axis direction, the first facing surface is an inclined surface on which the first gap becomes small toward the central portion side, and the second facing surface is an inclined surface on which the second gap becomes large toward the central portion side.

According to the sixth aspect, the first facing surface is an inclined surface on which the first gap becomes small toward the central portion side. In a general screw, a groove becomes shallow toward a central portion side, that is, a rib forming the groove becomes lower toward the central portion side, so that a central portion is recessed with respect to an outer side. Therefore, on the first facing surface, the gap between the groove forming surface and the facing surface is narrower, that is, the gap is prevented from becoming too large as compared with the general screw, so that a backflow of the material caused by the occurrence of the convection can be prevented.

According to a seventh aspect of the present disclosure, in the plasticizing device according to the second aspect, the groove forming surface has a first groove forming surface located in the first facing region and a second groove forming surface located in the second facing region, the first groove forming surface is inclined at the first angle, and the second groove forming surface is inclined at the second angle.

According to the seventh aspect, the first groove forming surface and the second groove forming surface are formed on the groove forming surface, so that the first facing region and the second facing region can be formed.

According to an eighth aspect of the present disclosure, in the plasticizing device according to the first aspect, the groove forming surface includes a protruding portion that protrudes toward the communication hole of the barrel.

According to the eighth aspect, a protrusion is provided in the central portion of the screw, so that the material can be efficiently supplied to the communication hole.

According to a ninth aspect of the present disclosure, in the plasticizing device according to the first aspect, the heating unit is a circular heating unit provided at a position overlapping the second facing region in a cross section perpendicular to the direction in which the rotation axis extends.

According to the ninth aspect, since the heating unit has a circular shape and is provided at the position overlapping the second facing region, the material can be efficiently heated and plasticized.

An injection molding machine according to a tenth aspect of the present disclosure includes the plasticizing device according to the first aspect, and an injection unit configured to inject a material plasticized by the plasticizing device into a mold.

According to the tenth aspect, the material can be prevented from flowing backward and the plasticized material can be injected from the injection unit.

A three-dimensional shaping apparatus according to an eleventh aspect of the present disclosure includes the plasticizing device according to the first aspect, and a discharge unit configured to discharge a material plasticized by the plasticizing device toward a table to shape a three-dimensional shaped object on the table.

According to the eleventh aspect, the material can be prevented from flowing backward and a three-dimensional shaped object can be shaped.

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. The following drawings are all schematic diagrams, and a part of components are omitted or simplified. In the drawings, an X axis direction is a horizontal direction, a Y axis direction is a horizontal direction and is a direction orthogonal to the X axis direction, and a Z axis direction is a vertical direction.

First Embodiment

First, an overall configuration of a three-dimensional shaping apparatus100according to a first embodiment including a plasticizing device1according to the first embodiment of the present disclosure will be described with reference toFIGS.1to7. “Three-dimensional shaping” in the specification refers to formation of a so-called three-dimensional shaped object, and includes, for example, formation of a shape having a thickness even in a so-called two-dimensional shape such as a flat plate shape and a shape formed of, for example, one layer. “Support” means supporting from a side and supporting from an upper side depending on circumstances in addition to supporting from a lower side.

As shown inFIG.1, the plasticizing device1in the three-dimensional shaping apparatus100according to the present embodiment includes a hopper2that accommodates pellets19serving as a solid material for forming a three-dimensional shaped object. The pellets19accommodated in the hopper2are supplied, via a supply pipe3, to a circumferential surface4aof a screw4that is a substantially cylindrical flat screw.

As shown inFIG.2, a spiral groove4bextending from the circumferential surface4ato a central portion Cp is formed in a groove forming surface18that is a bottom surface of the screw4. In other words, a rib4dformed along with the formation of the groove4bforms the groove forming surface18. Since the plasticizing device1according to the present embodiment has such a configuration, when the screw4is rotated by a drive motor6shown inFIG.1with a direction along the z axis direction as a rotation axis, the pellets19are sent from the circumferential surface4ato the central portion Cp, as shown inFIG.3. Although not shown inFIG.1, cooling water is circulated in the vicinity of the drive motor6in order to prevent a temperature rise of the drive motor6. Here, the central portion Cp is a portion corresponding to a periphery of a rotation center C (seeFIG.7) of the screw4as viewed from the direction along the Z axis direction, and also refers to a central portion of a barrel5to be described later, in addition to the central portion of the screw4.

As shown inFIGS.1and5, the barrel5is provided at a position facing the groove forming surface18of the screw4with a predetermined gap. A circular heater7A serving as a heating unit7is provided in the vicinity of a facing surface8that is an upper surface of the barrel5and that faces the groove forming surface18. With the screw4and the barrel5having such a configuration, the screw4is rotated to supply the pellets19into a space portion20, which corresponds to a position of the groove4band is formed between the groove forming surface18of the screw4and the facing surface8of the barrel5, and to move the pellets19from the circumferential surface4ato the central portion Cp. When the pellets19are moved in the space portion20formed by the groove4b, the pellets19are melted, that is, plasticized by heating of the circular heater7A. The pellets19are also pressurized by pressure accompanying with the movement of the pellets19in the narrow space portion20. In this manner, the pellets19are plasticized and supplied to a nozzle10avia a communication hole5a, and are injected from the nozzle10a.

As shown inFIGS.2,3, and5, a protrusion4eis provided on the central portion Cp of the screw4, and a part of the protrusion4eis fitted into an upper end portion of the communication hole5a. In other words, the screw4includes the protrusion4eat the center portion Cp, and the barrel5includes, in the communication hole5a, a recessed portion into which the protrusion4eis inserted and which is at a position facing the protrusion4e. With such a configuration, the plasticizing device1according to the present embodiment can efficiently supply a material obtained by plasticizing the pellets19into the communication hole5a.

Here, the position of the communication hole5aand the protrusion4ein the horizontal direction corresponds to a position of the rotation axis of the drive motor6. The central position of the communication hole5aand the protrusion4ein the horizontal direction corresponds to the rotation center C of the screw4shown inFIG.7. Although the plasticizing device1according to the present embodiment includes the protrusion4e, the plasticizing device1may not include the protrusion4e.

As shown inFIG.5which is a cross-sectional view as viewed from the horizontal direction, in the screw4of the plasticizing device1according to the present embodiment, the rib4dbecomes short and the groove4bbecomes shallow in the Z axis direction toward the center portion Cp. Similar to the screw4of the plasticizing device1according to the present embodiment, a general flat screw usually has a configuration in which the groove forming surface18is recessed toward the central portion Cp. Therefore, in order to keep a constant gap between the groove forming surface18and the facing surface8, a plasticizing device in the related art such as a three-dimensional shaping apparatus according to a reference example inFIG.11usually has a configuration in which the barrel5becomes thick toward the communication hole5a, that is, the facing surface8becomes high toward the central portion Cp. However, in the plasticizing device according to the related art that is used in the three-dimensional shaping apparatus according to the reference example inFIG.11, the material may flow backward between the groove forming surface18and the facing surface8as indicated by arrows inFIG.11.

On the other hand, as shown inFIG.5, in the barrel5of the plasticizing device1according to the present embodiment, a portion outside a boundary portion5bas viewed from the horizontal direction has the same configuration as the plasticizing device according to the reference example inFIG.11, and a portion inside the boundary portion5bas viewed from the horizontal direction is recessed toward the communication hole5a. In this manner, the gap is large between the groove forming surface18and the facing surface8at a position close to the central portion Cp where the communication hole5ais provided, so that the material between the groove forming surface18and the facing surface8can be effectively supplied in a direction toward the communication hole5aas indicated by arrows inFIG.5, and the material can be prevented from flowing backward. The arrows inFIG.5and the arrows inFIG.11are represented by straight lines along the facing surface8in order to make an easy image of a moving direction of the material. Actually, the material is moved along the spiral groove4b.

In summary here, the plasticizing device1according to the present embodiment is a plasticizing device that plasticizes a solid material and includes the drive motor6, the screw4rotated by the drive motor6and having the groove forming surface18on which the spiral groove4bis formed from the central portion Cp toward outside as viewed from the Z axis direction which is the rotation axis direction as the rotation axis of the drive motor6, the barrel5having the facing surface8facing the groove forming surface18and provided with the communication hole5aat a position facing the central portion Cp, and the heating unit7configured to heat the barrel5. As shown inFIG.5, a first facing region28aand a second facing region28bare provided between the groove forming surface18and the facing surface8. In the first facing region28a, the groove forming surface18and the facing surface8face each other with a first gap G1. The second facing region28bis provided at a position where the groove forming surface18and the facing surface8face each other and that is closer to a central portion Cp side than the first facing region28a. In the second facing region28b, a second gap G2that is a gap between the groove forming surface18and the facing surface8is larger than that in the first facing region28a. In this manner, provided between the groove forming surface18and the facing surface8are the first facing region28aand the second facing region28bin which the gap between the groove forming surface18and the facing surface8is large at the position close to the central portion Cp where the communication hole5ais provided, so that the material can be easily concentrated from the first facing region28ato the second facing region28b, and the material can be prevented from flowing backward from a second facing region28bside to a first facing region28aside. Although the heating unit7is configured to heat the barrel5in order to plasticize the solid material in the present embodiment, the heating unit7may be used to heat the screw4.

Here, a configuration in which the first facing region28aand the second facing region28bare provided between the groove forming surface18and the facing surface8does not include a configuration in which the groove forming surface18and the facing surface8are aligned in one straight line as viewed from a plane direction (the horizontal direction) defined by the X axis and the Y axis, that is, a configuration in which there is no boundary between the first facing region28aand the second facing region28b. This is because the configuration in which there is no boundary between the first facing region28aand the second facing region28bmay not efficiently move the material to the central portion Cp side. In the present embodiment, the boundary portion5bbetween a first facing surface8aand a second facing surface8bis the boundary between the first facing region28aand the second facing region28bas shown inFIG.5. Here, the “central portion Cp” can be set, for example, in a range of about one third of an outer diameter from a central position in a plan view.

Each of the first gap G1and the second gap G2may be an average gap between the groove forming surface18and the facing surface8. Therefore, a description of the second gap G2being larger than the first gap G1refers to that it is sufficient if an average gap in the second facing region28bis larger than an average gap in the first facing region28a, and refers to that an average gap in the second facing region28bis larger than an average gap in the first facing region28aeven in a configuration in which the groove forming surface18and the facing surface8are provided with recesses and protrusions or steps, or in a configuration in which the groove forming surface18and the facing surface8are not flat surfaces but curved surfaces. The gap between the groove forming surface18and the facing surface8may be, for example, a gap from a tip of the rib4dof the groove forming surface18to the facing surface8.

Here, as shown inFIG.5, the second gap G2becomes large toward the central portion Cp in the cross section along the Z axis direction. In other words, the second gap G2becomes large toward the central portion Cp, and in a cross section along a rotation axis direction that is a direction in which the rotation axis extends, at least one of the groove forming surface18and the facing surface8corresponding to the first facing region28ais inclined at a first angle with respect to an intersecting direction intersecting perpendicularly with the rotation axis direction, and at least one of the groove forming surface18and the facing surface8corresponding to the second facing region28bis inclined at a second angle with respect to the intersecting direction. The first angle and the second angle are different angles. That is, as viewed from a direction along the horizontal direction, an inclination angle of the facing surface8corresponding to the second facing region28bwith respect to the horizontal direction is different from an inclination angle of the facing surface8corresponding to the first facing region28awith respect to the horizontal direction. In this manner, an inclination angle of at least one of the groove forming surface18and the facing surface8in the second facing region28bwith respect to the horizontal direction is different from that in the first facing region28a, and the gap between the groove forming surface18and the facing surface8in the second facing region28bbecomes large toward the central portion Cp side. Thereby, in the second facing region28b, the material is easily concentrated toward the central portion Cp where the communication hole5ais provided. Therefore, the material can be prevented from flowing backward in the second facing region28b.

As shown inFIG.5, the facing surface8has the first facing surface8alocated in the first facing region28aand the second facing surface8bthat is located in the second facing region28band that has an angle different from the first facing surface8aas viewed from the horizontal direction. With the plasticizing device1according to the present embodiment having such a configuration, the first facing region28aand the second facing region28bare formed. Alternatively, two surfaces having different angles as viewed from the horizontal direction may not be provided on the facing surface8and two surfaces having different angles as viewed from the horizontal direction may be provided on the groove forming surface18.

As shown inFIG.5, as viewed from the horizontal direction, the first facing surface8ais an inclined surface at which the first gap G1becomes small toward the central portion Cp side, and the second facing surface8bis an inclined surface at which the second gap G2becomes large toward the central portion Cp side. As described above, in the screw4according to the present embodiment, similar to the general screw, the groove4bbecomes shallow toward the central portion Cp side, that is, the rib4dfor forming the groove4bbecomes lower toward the central portion Cp side, so that the entire screw4is in a state in which the central portion Cp is recessed with respect to an outer side. Therefore, at the first facing surface8a, the gap between the groove forming surface18and the facing surface8is narrowed with respect to the screw4in the present embodiment. That is, in the present embodiment, the gap is prevented from becoming too large, so that a backflow of the material caused by the occurrence of convection is prevented. As shown inFIG.5, the facing surface8is formed into a mountain shape as viewed from the horizontal direction, so that the pellets19can be accumulated at an outer side of the screw4, and an occurrence of a poor material movement caused by too early plasticization of the pellets19can be prevented.

As described above, the heating unit7is the circular heater7A that is a circular heating unit, and is provided at a position overlapping the second facing region28bas viewed from the Z axis direction as shown inFIG.4. The heating unit7is provided at the position overlapping the second facing region28band has a circular shape, so that the material can be efficiently heated and plasticized.

As shown inFIG.4and the like, the communication hole5athat is a movement path of the melted pellets19is formed in the central portion Cp of the barrel5in a plan view. As shown inFIG.1, the communication hole5ais continuous with the nozzle10aof an injection unit10as a discharge unit that discharges the material. A filter (not shown) is provided in the communication hole5a. Although a groove is not formed in the barrel5according to the present embodiment, a groove continuous with the communication hole5amay be formed in the facing surface8of the barrel5. When the groove continuous with the communication hole5ais formed in the facing surface8, the material may be easily gathered toward the communication hole5a.

Here, the injection unit10can continuously inject the plasticized material in a fluid state from the nozzle10a. As shown inFIG.1, the injection unit10is provided with a heater9for heating the material to have a desired viscosity. The material injected from the injection unit10is injected into a linear shape. Then, the material is linearly injected from the injection unit10to form a material layer M as shown inFIG.6.

In the three-dimensional shaping apparatus100according to the present embodiment, the plasticizing device1includes the hopper2, the supply pipe3, the screw4, the barrel5, the drive motor6, the injection unit10, and the like. The three-dimensional shaping apparatus100according to the present embodiment includes one plasticizing device1configured to inject a constituent material. Alternatively, the three-dimensional shaping apparatus100may include a plurality of plasticizing devices1configured to inject a constituent material, or may include a plasticizing device1configured to inject a support material. Here, the support material is a material for forming a support material layer used to support a constituent material layer.

As shown inFIG.1, the three-dimensional shaping apparatus100according to the present embodiment includes a stage unit22for placing a constituent material layer formed by the material injected from the plasticizing device1. The plasticizing device1and the stage unit22are accommodated in a constant temperature bath (not shown). The stage unit includes a plate11serving as a table on which the constituent material layer is actually placed. The stage unit22includes a first stage12on which the plate11is placed and whose position can be changed along the Y axis direction by driving a first drive unit15. In addition, the stage unit22includes a second stage13on which the first stage12is placed and whose position can be changed along the X axis direction by driving a second drive unit16. Further, the stage unit22includes a base portion14that can change a position of the second stage13along the Z axis direction by driving a third drive unit17.

As shown inFIG.1, the three-dimensional shaping apparatus100according to the present embodiment is electrically coupled to a control unit23that controls various kinds of driving of the plasticizing device1and various kinds of driving of the stage unit22. Components of the plasticizing device1and the stage unit22are driven under the control of the control unit23.

Next, a detailed configuration of the barrel5according to the present embodiment will be described with reference toFIG.7. In the barrel5according to the present embodiment, when a length from the boundary portion5bas a side end portion of the first facing region in a plane defined by the X axis and the Y axis to the rotation center C of the screw4in the second facing region28bis defined as L1, L1is about 36.5 mm. When a length from a first virtual connection point C1to a second virtual connection point C2is defined as L2, L2is about 4 mm, in which the first virtual connection point C1is a connection point between the first facing region28aand the rotation center C of the screw4when the first facing region28ais assumed to extend to the rotation center C of the screw4, and the second virtual connection point C2is a connection point between the second facing region28band the rotation center C of the screw4when the second facing region28bis assumed to extend to the rotation center C of the screw4. When a point where the rotation center C of the screw4intersects with the plane defined by the X axis and the Y axis from the boundary portion5bis defined as C3, a distance L2afrom the first virtual connection point C1to C3is about 1 mm, and a distance L2bfrom the second virtual connection point C2to C3is about 3 mm. An angle Θ formed between a line along the Z axis direction and passing through the rotation center C of the screw4and a virtual line extending from the boundary portion5bto the second virtual connection point C2is about 85°.

In other words, an inclination angle of the second facing surface8bwith respect to the horizontal direction is about 5° in the second facing region28b. When the inclination angle of the second facing surface8bwith respect to the horizontal direction is set to 5° or less, the second gap G2that is a gap between the groove forming surface18and the facing surface8in the second facing region28bcan be prevented from becoming too large. When the second gap G2is too large, convection may occur in the second facing region28b, causing the material to flow backward. When the second gap G2is prevented from becoming too large, the backflow of the material caused by the occurrence of the convection in the second facing region28bcan be prevented.

L2/L1approximates to 1/9 in the barrel5according to the present embodiment. It is preferable to satisfy a relationship of L2/L1<1/9 as in the barrel5according to the present embodiment. When a relationship of L2/L1<1/9 is satisfied, the second gap G2that is the gap between the groove forming surface18and the facing surface8in the second facing region28bcan be prevented from becoming too large. In particular, when L2/L1is larger than 1/5, the material may flow backward.

In the barrel5according to the present embodiment, when a length from the boundary portion5bto an outer end portion in the first facing region28ain the plane defined by the X axis and the Y axis is defined as L3, L3is about 23.5 mm. L1/L3approximates to 1.6 in the barrel5according to the present embodiment. It is preferable to satisfy a relationship of L1/L3of 1.5 or more and 2.0 or less as in the barrel5according to the present embodiment. In other words, a ratio of a length of a range of the second facing region28bto a length of a range of the first facing region28aas viewed from the plane direction defined by the X axis and the Y axis is preferably 1.5 times or more and 2.0 times or less. This is because when the ratio is too small, it may be difficult to concentrate the material from the first facing region28ato the second facing region28b, when the ratio is too large, it may be difficult to concentrate the material toward the central portion Cp in the second facing region28b, and such adverse effects can be prevented by setting the ratio to 1.5 times or more and 2.0 times or less.

In other words, the boundary portion5bis preferably at a position satisfying a relationship indicated by the following expression (1).
1/3≤Lb/La≤1/2.5  (1)

(La represents a linear distance from an outer end portion of the groove forming surface18or the facing surface8in the horizontal direction to the rotation center C of the rotation axis, and corresponds to L1+L3inFIG.7. Lb represents a linear distance from the outer end portion to the boundary portion5bin the horizontal direction, and corresponds to L3inFIG.7.)

That is, a ratio of a linear distance from an outer end portion where the screw4and the barrel5face each other in the horizontal direction to the boundary portion5bbetween the first facing region28aand the second facing region28bwith respect to a linear distance from the outer end portion where the screw4and the barrel5face each other in the horizontal direction to the rotation center C of the screw4is preferably 1/3 or more and 1/2.5 or less. This is because when the ratio is too large, it may be difficult to concentrate the material from the first facing region28ato the second facing region28b, when the ratio is too small, it may be difficult to concentrate the material toward the central portion Cp in the second facing region28b, and such adverse effects can be prevented by setting the ratio to 1/3 or more and 1/2.5 or less.

Second Embodiment

Next, the plasticizing device1according to a second embodiment will be described with reference toFIG.8.FIG.8is a diagram corresponding toFIG.4showing the plasticizing device1according to the first embodiment. Components same as those in the first embodiment are denoted by the same reference numerals inFIG.8, and a detailed description is omitted. Here, the plasticizing device1according to the present embodiment has characteristics same as those of the plasticizing device1according to the first embodiment, and has a shape same as the shape of the plasticizing device1according to first embodiment except for those described below.

As shown inFIG.8, the plasticizing device1according to the present embodiment includes four rod-like heaters7B extending in the Y axis direction as the heating unit7, instead of the circular heater7A. As described above, the present disclosure can use heaters having various shapes as the heating unit7.

Third Embodiment

Next, the plasticizing device1according to a third embodiment will be described with reference toFIG.9.FIG.9is a diagram corresponding toFIG.5showing the plasticizing device1according to the first embodiment. Components same as those in the first embodiment are denoted by the same reference numerals inFIG.9, and a detailed description is omitted. Here, the plasticizing device1according to the present embodiment has characteristics same as those of the plasticizing device1according to the first embodiment, and has a shape same as the shape of the plasticizing device1according to first embodiment except for those described below.

As described above, in the plasticizing device1according to the first embodiment, the first facing region28aand the second facing region28bare formed by forming the first facing surface8aand the second facing surface8bon the facing surface8. On the other hand, as shown inFIG.9, in the plasticizing device1according to the present embodiment, the first facing region28aand the second facing region28bare formed by forming a first groove forming surface18aand a second groove forming surface18bon the groove forming surface18. In other words, the groove forming surface18in the plasticizing device1according to the present embodiment has the first groove forming surface18alocated in the first facing region28aand the second groove forming surface18bthat is located in the second facing region28band that has an inclination angle different from an inclination angle of the first groove forming surface18aas viewed from the plane direction defined by the X axis and the Y axis.

In this manner, according to the present disclosure, the first facing region28aand the second facing region28bmay be formed by forming the first facing surface8aand the second facing surface8bon the facing surface8, or the first facing region28aand the second facing region28bmay be formed by forming the first groove forming surface18aand the second groove forming surface18bon the groove forming surface18. Further, the first facing region28aand the second facing region28bmay be formed by forming the first facing surface8aand the second facing surface8bon the facing surface8and by forming the first groove forming surface18aand the second groove forming surface18bon the groove forming surface18.

Injection Molding Machine

The plasticizing device according to the present disclosure, such as the plasticizing devices1according to the first embodiment to the third embodiment, can also be used in an apparatus other than the three-dimensional shaping apparatus100. Hereinafter, an embodiment of an injection molding machine including the plasticizing device according to the present disclosure will be described with reference toFIG.10.

An injection molding machine200according to the present embodiment includes the plasticizing device1. The plasticizing device1includes the screw4having the groove forming surface18and the barrel5having the facing surface8as in the plasticizing device1according to the first embodiment. The injection molding machine200according to the present embodiment further includes an injection control mechanism.210, a mold unit230, and a mold clamping device240.

The plasticizing device1includes the screw4and the barrel5. As described above, specific configurations of the groove forming surface18of the screw4and the facing surface8of the barrel5are the same as those of the screw4and the barrel5according to the first embodiment. Under the control of a control unit250, the plasticizing device1plasticizes at least apart of materials supplied to the groove4bof the screw4to generate a paste-like melted material having flowability, and guides the melted material to the injection unit10.

The injection control mechanism210includes an injection cylinder211, a plunger212, and a plunger drive unit213. The injection control mechanism210has a function of injecting a melted material in the injection cylinder211into a cavity Cv to be described later. The injection control mechanism210controls an injection amount of the melted material from the nozzle10aunder the control of the control unit250. The injection cylinder211is a substantially cylindrical member coupled to the communication hole5aof the barrel5, and is internally provided with the plunger212. The plunger212is moved inside the injection cylinder211, and pressure-feeds the melted material in the injection cylinder211to a nozzle10aside. The plunger212is driven by the plunger drive unit213implemented by a motor.

The mold unit230includes a movable mold231and a fixed mold232. The movable mold231and the fixed mold232are provided to face each other, and the cavity Cv that is a space corresponding to a shape of a molded product is provided between the movable mold231and the fixed mold232. The melted material is pressure-fed by the injection control mechanism210into the cavity Cv and is injected via the nozzle10a.

The mold clamping device240includes a mold drive unit241and has a function of opening and closing the movable mold231and the fixed mold232. Under the control of the control unit250, the mold clamping device240drives the mold drive unit241to move the movable mold231to open or close the mold unit230.

Since the injection molding machine200according to the present embodiment is provided with the plasticizing device1that includes the screw4having the groove forming surface18and the barrel5having the facing surface8and is the same as the plasticizing device1according to the first embodiment, the melted material can be stably supplied from the plasticizing device1. Therefore, the melted material can be stably injected from the nozzle10a. Instead of the plasticizing device1that includes the screw4having the groove forming surface18and the barrel5having the facing surface8and is the same as the plasticizing device1according to the first embodiment, the injection molding machine200may be provided with the plasticizing device1that includes the screw4having the groove forming surface18and the barrel5having the facing surface8and is the same as the plasticizing device1according to the second embodiment or the third embodiment.

The present disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from the scope of the disclosure. In order to solve some or all of problems described above, or to achieve some or all of effects described above, technical features in the embodiments corresponding to technical features in aspects described in the summary can be replaced or combined as appropriate. The technical features can be deleted as appropriate unless the technical features are described as essential in the present specification.