Material extrusion mechanism and molding machine

Abstract

This invention provides a technology that can reduce the pinching of resin pellets in a material extrusion mechanism in which a screw rotates around a rotation axis aligned vertically. [Solution] The material extrusion mechanism comprises a cylinder having a supply port for supplying material and positioned vertically, a screw having a helical flight section and rotating around a rotation axis positioned vertically, a first cooling section provided to surround a part of the screw, a heating section provided below the first cooling section to surround a part of the screw, and at least one nozzle for discharging plasticized material, wherein at least a part of the supply port overlaps with the first cooling section in the horizontal direction, and the screw has a first portion where the outer diameter of the flight section is a first diameter, and a second portion where the outer diameter of the flight section is a second diameter smaller than the first diameter, wherein the first portion overlaps with the heating section in the horizontal direction, and the second portion overlaps with the first cooling section in the horizontal direction.

Description

Technical Field

[0001] The present disclosure relates to a material extrusion mechanism and a molding machine.

Background Art

[0002] Patent Document 1 discloses a technique for reducing the entrainment of resin pellets by cutting out the outer peripheral portion of the screw flight of a screw used in a material supply device that supplies resin pellets to an injection molding machine.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, reduction of entrainment of resin pellets in a material supply device has been studied. However, reduction of entrainment of resin pellets in a material extrusion mechanism that plasticizes a material by rotating a screw around a rotation axis along the vertical direction has not been studied.

Means for Solving the Problems

[0005] A material extrusion mechanism is provided according to a first embodiment of the present disclosure. The material extrusion mechanism comprises a cylinder having a feed port for supplying material and positioned vertically, a screw having a helical flight portion and rotating within the cylinder about a vertical axis of rotation, a first cooling portion provided to surround a portion of the screw, a heating portion provided below the first cooling portion and surrounding a portion of the screw, and at least one nozzle for discharging the plasticized material within the cylinder, wherein at least a portion of the feed port overlaps the first cooling portion in the horizontal direction, and the screw has a first portion having an outer diameter of the flight portion that is a first diameter, and a second portion having an outer diameter of the flight portion that is a second diameter smaller than the first diameter, wherein the first portion overlaps the heating portion in the horizontal direction, and the second portion overlaps the first cooling portion in the horizontal direction.

[0006] A second embodiment of the present disclosure provides a molding machine. This molding machine comprises at least one of the material extrusion mechanisms of the first embodiment, a material stacking section into which the material extruded from the nozzle is stacked, and a moving mechanism for changing the relative position between the material extrusion mechanism and the material stacking section, and forms a molded product by stacking the material extruded from the nozzle. [Brief explanation of the drawing]

[0007] [Figure 1] An explanatory diagram showing the general configuration of a molding machine. [Figure 2] A perspective view showing the schematic configuration of the screw. [Figure 3] An explanatory diagram showing the configuration of the first cooling channel. [Figure 4] An explanatory diagram showing the configuration of the second cooling channel. [Figure 5] An explanatory diagram showing the connection between the cooled part of the cylinder and the case of the screw drive unit. [Figure 6] A magnified view of the vicinity of the supply port in Figure 1. [Figure 7] A perspective view of the plasticizing section near the supply port, cut at a cross-section including the rotation axis. [Figure 8] Perspective view of the screw near the boundary between the first and second parts. [Figure 9] A diagram illustrating the shape of the flight portion in a cross-section of a screw, including the axis of rotation. [Figure 10] An explanatory diagram showing the schematic configuration of the molding machine in the second embodiment. [Figure 11] An explanatory diagram showing the general configuration of the processing section. [Figure 12] An explanatory diagram showing the schematic configuration of the molding machine in the third embodiment. [Figure 13] A diagram illustrating the shape of the flight portion in a cross-section of a screw including the rotating shaft in another embodiment. [Figure 14] A diagram illustrating the shape of the flight portion in a cross-section of a screw including the rotating shaft in another embodiment. [Modes for carrying out the invention]

[0008] A. First Embodiment: Figure 1 is an explanatory diagram showing the schematic configuration of the molding machine 100. Figure 1 shows arrows representing the mutually orthogonal X, Y, and Z directions. The X and Y directions are parallel to the horizontal plane. The Z direction is parallel to the vertical direction. The X, Y, and Z directions in Figure 1 and the X, Y, and Z directions in other figures point to the same directions. When specifying the direction, the positive direction indicated by the arrow is denoted as "+" and the negative direction opposite to the direction indicated by the arrow is denoted as "-", and both positive and negative signs are used in the direction notation. The +Z direction is also called "up" and the -Z direction is also called "down".

[0009] The molding machine 100 comprises a material extrusion mechanism 200, a material lamination section 300, a moving mechanism 400, and a control unit 500. The molding machine 100 forms a molded product by laminating the material extruded from the material extrusion mechanism 200 onto the material lamination section 300. Under the control of the control unit 500, the molding machine 100 extrudes plasticizing material from the nozzle hole 92 of the discharge section 90 of the material extrusion mechanism 200 toward the molding surface 310 of the material lamination section 300, while driving the moving mechanism 400 to change the relative position between the nozzle hole 92 and the molding surface 310, thereby forming a molded product in which layers of plasticizing material are laminated on the molding surface 310. The material lamination section 300 is also called a stage.

[0010] As described above, the moving mechanism 400 changes the relative position between the nozzle hole 92 and the molding surface 310. In this embodiment, the moving mechanism 400 supports the material stacking section 300, and changes the relative position between the nozzle hole 92 and the molding surface 310 by moving the material stacking section 300 relative to the material extrusion mechanism 200. In this embodiment, the moving mechanism 400 is composed of a three-axis positioner that moves the material stacking section 300 in three axial directions (X, Y, and Z) using the driving force of three motors. Each motor is driven under the control of the control unit 500. Note that the moving mechanism 400 may also be configured to change the relative position between the nozzle hole 92 and the molding surface 310 by moving the material extrusion mechanism 200 without moving the material stacking section 300, rather than moving the material stacking section 300. Furthermore, the moving mechanism 400 may be configured to change the relative position between the nozzle hole 92 and the molding surface 310 by moving both the material lamination section 300 and the material extrusion mechanism 200.

[0011] The control unit 500 is composed of a computer including one or more processors, a main memory device, and an input / output interface for inputting and outputting signals to and from the outside. In the present embodiment, the control unit 500 controls the operations of the material extrusion mechanism 200 and the moving mechanism 400 by the processor executing programs and instructions loaded onto the main memory device, and executes a molding process for molding a molded product. The operations include changing the three-dimensional relative positions of the material extrusion mechanism 200 and the material stacking unit 300. Note that the control unit 500 may be composed of a combination of a plurality of circuits instead of a computer.

[0012] Under the control of the control unit 500, the material extrusion mechanism 200 discharges a plasticized material obtained by plasticizing a solid-state material onto the material stacking unit 300. The material extrusion mechanism 200 includes a material supply unit 20 that is a material supply source, a plasticizing unit 30 that converts the material into a plasticized material, and a discharge unit 90 that discharges the plasticized material supplied from the plasticizing unit 30 toward the material stacking unit 300. Note that "plasticization" is a concept including melting and means changing from a solid state to a state having fluidity. Specifically, in the case of a material in which glass transition occurs, plasticization means raising the temperature of the material above the glass transition point. In the case of a material in which glass transition does not occur, plasticization means raising the temperature of the material above the melting point.

[0013] The material supply unit 20 stores pellet-shaped materials. The material supply unit 20 is composed of, for example, a hopper. As the material, for example, thermoplastic resins such as polypropylene resin (PP), polyethylene resin (PE), polyacetal resin (POM), and polyphenylene sulfide resin (PPS) are used. Below the material supply unit 20, a communication path 21 connecting between the material supply unit 20 and the plasticizing unit 30 is provided. The communication path 21 is connected to a cylinder 40 described later obliquely from above. The communication path 21 has a cylindrical shape. The material supply unit 20 supplies the material to the plasticizing unit 30 through the communication path 21.

[0014] The plasticizing unit 30 plasticizes at least a portion of the material supplied from the material supply unit 20, generating a fluid, paste-like plasticizing material which is then guided to the discharge unit 90. The plasticizing unit 30 comprises a cylinder 40, a screw 50, a screw drive unit 60, a cooling unit 70, and a heating unit 80. The screw drive unit 60, the cylinder 40, and the discharge unit 90 are arranged in this order from top to bottom.

[0015] The cylinder 40 comprises a main body portion 41 and a nozzle fixing portion 46 provided at the lower end of the main body portion 41. The main body portion 41 has a cylindrical shape centered on a central axis AX1. The main body portion 41 is arranged so that the central axis AX1 is aligned vertically. The main body portion 41 has a cooled portion 42 and a heated portion 43 located below the cooled portion 42. A supply port 44 is provided at the connection between the cooled portion 42 and the heated portion 43, through which material is supplied from the material supply unit 20 via a communication passage 21. Specifically, the supply port 44 spans the lower end of the cooled portion 42 and the upper end of the heated portion 43. The upper end of the cooled portion 42 is formed in a flange shape. A screw drive unit 60 is fixed to the upper end of the cooled portion 42. A nozzle fixing portion 46 is fixed to the lower end of the heated portion 43. The nozzle fixing portion 46 has a disc shape. A through-hole 47 is provided in the center of the nozzle fixing portion 46, extending in the Z direction and passing through the nozzle fixing portion 46. A discharge portion 90 is connected to the lower end of the nozzle fixing portion 46.

[0016] In this embodiment, the cooled part 42, the heated part 43, and the nozzle fixing part 46 are each formed of stainless steel. In this embodiment, the cooled part 42 and the heated part 43 are integrally formed. For example, the cooled part 42 and the heated part 43 can be integrally formed by joining the cooled part 42 and the heated part 43 using a metal joining technique such as diffusion bonding or HIP (Hot Isostatic Press) bonding. The cooled part 42 and the heated part 43 may be integrally formed using a three-dimensional modeling technique. Note that at least one of the cooled part 42 and the heated part 43 may be formed of a metal material other than stainless steel, such as a titanium alloy, or may be formed of a resin material or a ceramic material. The cooled part 42 and the heated part 43 may be formed of different metal materials.

[0017] Figure 2 is a perspective view showing the schematic configuration of the screw 50. The configuration of the screw 50 will be described below with reference to Figures 1 and 2. The screw 50 is housed inside the cylinder 40. More specifically, the screw 50 is housed in a space enclosed by the main body 41 of the cylinder 40, the nozzle fixing part 46 of the cylinder 40, and the case 63 of the screw drive unit 60, which will be described later. The screw 50 has an axial shape centered on the rotation axis AX2. The screw 50 is positioned so that the rotation axis AX2 is aligned with the central axis AX1 of the main body 41 of the cylinder 40. The upper end of the screw 50 is connected to the screw drive unit 60. The tip 51 of the screw 50 is located near the through hole 47. A helical groove 52 centered on the rotation axis AX2 is provided on the side of the screw 50. The groove 52 is provided continuously from the part located above the supply port 44 of the screw 50 to the tip 51 of the screw 50. Between the grooves 52, a helical flight portion 53 is provided to separate the grooves 52. The value obtained by dividing the length in the direction along the rotation axis AX2 of the screw 50 by the diameter of the screw 50 is preferably about 5 to 10. In this embodiment, the screw 50 is made of hardened stainless steel. However, the screw 50 may be made of other metal materials such as titanium alloy, resin material, or ceramic material instead of hardened stainless steel. The specific configuration of the flight portion 53 of the screw 50 will be described later.

[0018] The screw drive unit 60 shown in Figure 1 comprises a drive motor 61, a reduction gear 62, and a case 63. The case 63 has a gear case portion 64 and a motor case portion 65. The gear case portion 64 is fixed to the upper end of the cooled portion 42 of the cylinder 40. The gear case portion 64 has a rectangular parallelepiped shape. The reduction gear 62 is housed inside the gear case portion 64. The motor case portion 65 is fixed to the upper surface of the gear case portion 64. The motor case portion 65 has a cylindrical shape. The drive motor 61 is housed in the hollow portion of the motor case portion 65. In this embodiment, a servo motor is used for the drive motor 61. In this embodiment, the reduction gear 62 is composed of gears or the like. The drive motor 61 is driven under the control of the control unit 500. The rotating shaft 66 of the drive motor 61 is connected to the upper end portion of the screw 50 via the reduction gear 62. The torque applied from the drive motor 61 via the reduction gear 62 causes the screw 50 to rotate around the rotation axis AX2 inside the cylinder 40. For example, a stepping motor may be used as the drive motor 61. The reduction gear 62 may be composed of pulleys, belts, etc. The screw drive unit 60 may also be configured without the reduction gear 62 and gear case 64, with the rotation axis 66 of the drive motor 61 connected to the upper end of the screw 50. The drive motor 61 is sometimes simply referred to as the motor. The horizontal width of the screw drive unit 60 is greater than the horizontal width of the first cooling unit 71, which is part of the cooling unit 70 described later.

[0019] The cooling unit 70 comprises a first cooling unit 71, a second cooling unit 72, and a refrigerant supply unit 73. The first cooling unit 71 and the second cooling unit 72 are passages through which the refrigerant flows. Hereinafter, the first cooling unit 71 will also be referred to as the first cooling passage 71, and the second cooling unit 72 will also be referred to as the second cooling passage 72.

[0020] The first cooling channel 71 is provided in the cylinder 40. The first cooling channel 71 is located inside the cooled section 42 in a three-dimensional path that passes near the supply port 44. At least a portion of the supply port 44 overlaps with the first cooling channel 71 in the horizontal direction. The first cooling channel 71 is composed of a hole with a three-dimensional path provided in the cooled section 42. One end of the first cooling channel 71 is connected to the second cooling channel 72. The other end of the first cooling channel 71 is connected to the refrigerant supply section 73 via a pipe or the like. The detailed configuration of the first cooling channel 71 will be described later.

[0021] The second cooling passage 72 is located inside the case 63. In this embodiment, the second cooling passage 72 is provided as a three-dimensional path passing through both the inside of the gear case 64 and the inside of the motor case 65. The second cooling passage 72 is composed of holes with a three-dimensional path provided in the gear case 64 and the motor case 65. One end of the second cooling passage 72 is connected to the refrigerant supply unit 73 via a pipe or the like. The other end of the second cooling passage 72 is connected to the first cooling passage 71. The detailed configuration of the second cooling passage 72 will be described later.

[0022] The refrigerant supply unit 73 is composed of a chiller that circulates refrigerant through the first cooling channel 71 and the second cooling channel 72, while removing the heat from the refrigerant that has flowed through the first cooling channel 71 and the second cooling channel 72. In this embodiment, the refrigerant supplied from the refrigerant supply unit 73 flows through the first cooling channel 71 and the second cooling channel 72 in that order. The refrigerant supply unit 73 is driven under the control of the control unit 500. In this embodiment, water is used as the refrigerant. However, other than water, for example, oil or air may be used as the refrigerant. Only the first cooling channel 71 may be connected to the refrigerant supply unit 73. In this case, for example, the refrigerant that has flowed from the first cooling channel 71 to the second cooling channel 72 may be discharged to the outside without circulating back to the refrigerant supply unit 73.

[0023] Figure 3 is an explanatory diagram showing the configuration of the first cooling channel 71 in this embodiment. Figure 3 shows the screw 50 along with the first cooling channel 71. In Figure 3, the external shape of the cylinder 40 is omitted, and the inner wall surface of the cylinder 40 that forms the first cooling channel 71 is shown. The first cooling channel 71 is provided so as to surround a part of the screw 50. In this embodiment, one first cooling channel 71 is arranged three-dimensionally in the cooled portion 42 of the cylinder 40. The first cooling channel 71 is arranged three-dimensionally by connecting a portion extending along the Z direction and a portion extending along the circumferential direction of a circle centered on the central axis AX1. The first cooling channel 71 is evenly distributed around the entire circumference of the cooled portion 42. The cooled portion 42 of the cylinder 40 is cooled by the flow of refrigerant through the first cooling channel 71. The first cooling channel 71 may branch inside the cooled portion 42. Multiple first cooling channels 71 may be provided inside the part to be cooled 42.

[0024] Figure 4 is an explanatory diagram showing the configuration of the second cooling channel 72 in this embodiment. Figure 4 shows a cross-section of the motor case portion 65. Figure 4 shows the path of the second cooling channel 72 provided inside the motor case portion 65 with a dashed line. In this embodiment, one second cooling channel 72 is arranged three-dimensionally in the motor case portion 65. The second cooling channel 72 is arranged three-dimensionally by connecting a portion extending along the Z direction and a portion extending along the circumferential direction of the cylindrical motor case portion 65. The second cooling channel 72 is evenly distributed around the entire circumference of the motor case portion 65. The second cooling channel 72 may branch inside the motor case portion 65. Multiple second cooling channels 72 may be provided inside the motor case portion 65.

[0025] Figure 5 is an explanatory diagram showing the connection between the cooled portion 42 of the cylinder 40 and the case 63 of the screw drive unit 60. In Figure 5, the case 63 is not shown, and the cylinder 40 is shown cut by a plane passing through the central axis AX1. In this embodiment, a groove communicating with the first cooling passage 71 is provided on the upper end surface of the cooled portion 42 of the cylinder 40. The groove provided on the upper end surface of the cooled portion 42 extends along the circumferential direction of a circle centered on the central axis AX1. On the lower surface of the gear case portion 64 of the case 63, a groove communicating with the second cooling passage 72 is provided, inverted from the groove provided on the upper end surface of the cooled portion 42. By connecting the cooled portion 42 and the gear case portion 64, the groove provided on the cooled portion 42 and the groove provided on the gear case portion 64 combine to connect the first cooling passage 71 and the second cooling passage 72. Grooves are provided on both sides of the groove in the cooled portion 42 into which O-rings 93 are fitted. The O-rings 93 are compressed by the cooled portion 42 and the gear case portion 64, thereby suppressing the leakage of refrigerant from between the cooled portion 42 and the gear case portion 64.

[0026] In this embodiment, the lower end surface of the cooled portion 42 is provided with a groove extending along the circumferential direction of a circle centered on the central axis AX1. The upper end surface of the heated portion 43 is provided with a groove that is the inverse of the groove provided on the lower end surface of the cooled portion 42. By connecting the cooled portion 42 and the heated portion 43, the groove provided on the lower end surface of the cooled portion 42 and the groove provided on the upper end surface of the heated portion 43 combine to form a part of the first cooling channel 71. Inside the cooled portion 42, there is a through hole that extends linearly along the central axis AX1. This through hole communicates with the groove provided on the upper end surface of the cooled portion 42 and the groove provided on the lower end surface of the cooled portion 42. This through hole forms a part of the first cooling channel 71.

[0027] The heating section 80 shown in Figure 1 is provided below the cooling section 70 and surrounds a part of the screw 50. Specifically, the heating section 80 surrounds the portion of the heated section 43 below the portion where the first cooling channel 71 is formed. In other words, the first cooling channel 71 is provided above the region of the heated section 43 that is heated by the heating section 80. The heating section 80 is an electric heater. The heating section 80 is, for example, a resistance heating type heater. In this embodiment, the heating section 80 is provided along the outer surface of the heated section 43, specifically the portion located between the supply port 44 and the discharge section 90. The heating section 80 may also be embedded in the outer surface of the heated section 43 located between the supply port 44 and the discharge section 90. The temperature of the heating section 80 is controlled by the control unit 500. For example, the control unit 500 may control the temperature of the heating section 80 using the temperature obtained by a temperature sensor provided in the heating section 80. The heating element 80 is not limited to an electric heater; it may also be a gas-heated heater or the like.

[0028] The discharge section 90 is provided on the lower surface of the nozzle fixing section 46 in the cylinder 40. In this embodiment, the discharge section 90 has eight nozzles 91. Each nozzle 91 has a nozzle hole 92 at its tip. The nozzle hole 92 communicates with a through hole 47 in the nozzle fixing section 46. The plasticizing material that flows into the internal flow path of each nozzle 91 from the through hole 47 is discharged from the nozzle hole 92. In this specification, the discharge of the plasticizing material from the nozzle hole 92 of the discharge section 90 is also referred to as "pushing the plasticizing material out of the nozzle hole 92". The discharge section 90 may have two to seven nozzles 91, or nine or more nozzles 91. Alternatively, the discharge section 90 may consist of a single nozzle 91.

[0029] Figure 6 is an enlarged view of the vicinity of the supply port 44 in Figure 1. Figure 7 is a perspective view of the plasticizing portion 30 near the supply port 44, cut in a cross-section including the rotating shaft AX2. The screw 50 has a first portion 110 whose outer diameter is the first diameter of the flight portion 53, a second portion 120 whose outer diameter is the second diameter of the flight portion 53 which is smaller than the first diameter, and a third portion 130 located above the flight portion 53 whose outer diameter is the first diameter of the screw 50. The first diameter is preferably slightly smaller than the inner diameter of the cylinder 40. For example, the difference between the first diameter and the inner diameter of the cylinder 40 is preferably 0.5 mm or less. The second diameter is determined based on the size of the pelletized material supplied from the material supply unit 20. The difference between the first diameter and the second diameter is preferably about the same as the diameter of the pelletized material.

[0030] The first portion 110 is provided in the region of the flight portion 53 surrounded by the heated portion 43 of the cylinder 40. The second portion 120 is provided above the first portion 110. The boundary between the first portion 110 and the second portion 120 is located in the vertical direction above the region of the heated portion 43 that is heated by the heating portion 80, and below the region of the heated portion 43 where the first cooling channel 71 is formed. In other words, the first portion 110 overlaps with the heating portion 80 in the horizontal direction. The first portion 110 is provided continuously from the boundary with the second portion 120 to the tip portion 51 of the screw 50.

[0031] The second portion 120 is provided in the area of ​​the flight portion 53 surrounded by the cooled portion 42 of the cylinder 40 and a part of the area surrounded by the heated portion 43 of the cylinder 40. That is, the second portion 120 overlaps with the cooling portion 70 in the horizontal direction. The second portion 120 is provided continuously from the boundary with the first portion 110 described above to the upper end of the flight portion 53.

[0032] Figure 8 is a perspective view of the screw 50 near the boundary between the first part 110 and the second part 120. The flight portion 53 has a stepped shape at the boundary between the first part 110 and the second part 120. That is, the outer diameter of the flight portion 53 changes from the first diameter to the second diameter at one position in the vertical direction. Alternatively, the outer diameter of the flight portion 53 may change smoothly from the first diameter to the second diameter at the boundary between the first part 110 and the second part 120.

[0033] Figure 9 illustrates the shape of the flight portion 53 in a cross-section of the screw 50 including the rotating shaft AX2. Hereinafter, the cross-section of the screw 50 including the rotating shaft AX2 will also be referred to as the first cross-section. In this embodiment, the shape of the first portion 110 and the shape of the second portion 120 in the first cross-section are the same. The cross-section of the flight portion 53 in the first cross-section is rectangular, having a first side 151 and a second side 152 parallel to the rotating shaft AX2. Here, the second side 152 is the side located at a position having the same outer diameter as the groove portion 52 of the screw 50. The first side 151 is located at a position further from the rotating shaft AX2 than the second side 152, and is the side located at the position where the outer diameter of the flight portion 53 is maximum. Note that the cross-section of the flight portion 53 in the first cross-section may be trapezoidal, where the length of the first side 151 is less than the length of the second side 152. Alternatively, the cross-section of the flight portion 53 in the first cross-section may be a substantially trapezoidal shape with rounded corners at both ends of the first side 151. The shape of the flight portion 53 in the first cross-section described above may be formed only in the second portion 120.

[0034] The third portion 130 shown in Figure 6 is located at the upper end of the screw 50. In this embodiment, the third portion 130 is provided at a height where the boundary between the cooled portion 42 and the gear case is located in the vertical direction. The third portion 130 may extend from the boundary with the second portion 120, which is the flight portion 53, to the upper end of the screw 50 connected to the screw drive portion 60.

[0035] According to the first embodiment described above, the material extrusion mechanism 200 includes a cylinder 40 having a supply port 44 into which material is supplied, a screw 50 that rotates inside the cylinder 40 around a rotation axis AX2 in the vertical direction, a first cooling section 71 provided to surround a part of the screw 50, and a heating section 80 provided below the first cooling section 71 to surround a part of the screw 50, wherein at least a part of the supply port 44 overlaps with the first cooling section 71 in the horizontal direction, and the screw 50 has a first portion 110 in which the outer diameter of the flight section 53 is a first diameter, and a second portion 120 in which the outer diameter of the flight section 53 is a second diameter smaller than the first diameter, wherein the first portion 110 overlaps with the heating section 80 in the horizontal direction, and the second portion 120 overlaps with the first cooling section 71 in the horizontal direction. Therefore, in a material extrusion mechanism 200 that plasticizes a material by rotating a screw 50 around a rotation axis AX2 along the vertical direction, the possibility of the material supplied from the supply port 44 getting caught between the screw 50 and the cylinder 40 can be reduced. Also, in this embodiment, compared to the case where the outer diameter of the flight portion 53 that overlaps with the first cooling portion 71 in the horizontal direction is the first diameter, the screw 50 is less likely to be cooled by the first cooling portion 71. Therefore, compared to the case described above, it is possible to melt the material in the space between the screw 50 and the cylinder 40 more easily. In addition, when the material extrusion mechanism 200 is a small device, the rotation torque of the screw 50 is small, so the rotation of the screw 50 is likely to stop if the material gets caught between the screw 50 and the cylinder 40. In this embodiment, since the material is less likely to get caught between the screw 50 and the cylinder 40, even if the material extrusion mechanism 200 is a small device, it is possible to make it less likely for the rotation of the screw 50 to stop.

[0036] In a material extrusion mechanism 200 that plasticizes a material by rotating a screw 50 around a rotation axis AX2 aligned vertically, in order to shorten the vertical length of the screw 50, it is necessary to increase the vertical temperature gradient of the screw 50. Specifically, it is necessary to cool the vicinity of the supply port 44 with a cooling unit 70 to prevent the material supplied from melting near the supply port 44 due to the heat of the heating unit 80. This is because if the material melts near the supply port 44, it becomes difficult to transport the material to the discharge unit 90 by the rotation of the screw 50. In this embodiment, the cylinder 40 has a cooled portion 42 that is cooled by the cooling unit 70, and a heated portion 43 that is located below the cooled portion 42 and heated by the heating unit 80. The cooling unit 70 is a cooling channel through which a refrigerant flows, and the cooling channel is provided above the cooled portion 42 and the heated portion 43 that is heated by the heating unit 80. Therefore, the vertical temperature gradient of the screw 50 can be increased, and in a material extrusion mechanism 200 with a short vertical length of the screw 50, the possibility of the material supplied from the supply port 44 getting caught between the screw 50 and the cylinder 40 can be reduced. In addition, the vertical length of the material extrusion mechanism 200 can be shortened.

[0037] Furthermore, in this embodiment, the material extrusion mechanism 200 further includes a screw drive unit 60 provided above the screw 50 and having a motor for rotating the screw 50. The screw 50 has a third portion 130 whose outer diameter is the first diameter of the flight portion 53, and the third portion 130 is located at the upper end of the screw 50. Therefore, it is possible to prevent the material supplied into the cylinder 40 from the supply port 44 from entering the screw drive unit 60.

[0038] Furthermore, in this embodiment, a screw drive unit 60 is provided above the screw 50 and has a motor for rotating the screw 50, and the horizontal width of the screw drive unit 60 is greater than the horizontal width of the cooling unit 70. Therefore, a motor large enough to obtain the output necessary for rotating the screw 50 can be installed in the screw drive unit 60.

[0039] Furthermore, in this embodiment, the cross-section of the flight portion 53 in the cross-section of the screw 50 including the rotating shaft AX2 is trapezoidal in shape, having a first side 151 and a second side 152 parallel to the rotating shaft AX2, with the first side 151 located further from the rotating shaft AX2 than the second side 152, and the length of the first side 151 being less than or equal to the length of the second side 152. Therefore, when the screw 50 rotates around the rotating shaft AX2, it is possible to easily convey the material downwards.

[0040] Furthermore, in this embodiment, the material extrusion mechanism 200 has two or more nozzles 91. Therefore, compared to the case where the material extrusion mechanism 200 has one nozzle 91, the productivity of molded products can be improved.

[0041] Furthermore, in this embodiment, the molding machine 100 includes the material extrusion mechanism 200 described above, a material stacking section 300 where the material extruded from the nozzle 91 is stacked, and a moving mechanism 400 that changes the relative position between the material extrusion mechanism 200 and the material stacking section 300. The molding machine forms a molded product by stacking the material extruded from the nozzle 91. Therefore, in the molding machine 100, the possibility of the material supplied from the supply port 44 getting caught between the screw 50 and the cylinder 40 can be reduced.

[0042] B. Second Embodiment: Figure 10 is an explanatory diagram showing the schematic configuration of the molding machine 100b in the second embodiment. The molding machine 100b comprises a molding cell 101 and a processing cell 102. Inside the molding cell 101 are a material extrusion mechanism 200, a material stacking section 300, a moving mechanism 400, and a control unit 500. In the second embodiment, the material extrusion mechanism 200, the material stacking section 300, and the moving mechanism 400 are collectively referred to as the molding unit. Inside the processing cell 102 are a processing section 600, which will be described later. In the second embodiment, the control unit 500 controls the molding unit and the processing section 600. Note that the material extrusion mechanism 200, the material stacking section 300, the moving mechanism 400, the control unit 500, and the processing section 600 may be housed in a single cell.

[0043] Figure 11 is an explanatory diagram showing the schematic configuration of the processing unit 600. The processing unit 600 comprises a cutting unit 610, a stage 620, and a moving mechanism 630. The processing unit 600 processes the molded product formed by the molding unit. Under the control of the control unit 500, the processing unit 600 rotates the cutting tool 611 mounted on the cutting unit 610 and drives the moving mechanism 630 to change the relative position between the cutting tool 611 and the stage 620, thereby cutting the molded product formed by the molding unit with the cutting tool 611. In the second embodiment, for example, the injection unit forms a molded product in the shape of a roughly rectangular parallelepiped, and the processing unit 600 manufactures a mold used for injection molding by cutting the molded product to form the shape of the cavity. Note that the processing unit 600 may perform grinding of the molded product instead of cutting it.

[0044] The stage 620 is supported by the moving mechanism 630. The stage 620 has a cutting surface 621 facing the cutting section 610. The molded product formed in the molding unit is transported from the molding cell 101 to the processing cell 102 by, for example, a robot, and fixed on the cutting surface 621. In this embodiment, the cutting surface 621 is provided parallel to the horizontal plane. The configuration of the moving mechanism 630 is the same as that of the moving mechanism 400, so its description is omitted. Note that if the injection unit and the processing section 600 are housed in a single cell, the molding machine 100b does not need to have the stage 620 and the moving mechanism 630. In this case, the cutting section 610 processes the molded product fixed on the molding surface 310 of the material lamination section 300.

[0045] The cutting unit 610 is a cutting device that rotates a cutting tool 611 attached to the shaft at the tip of the head to cut a molded product fixed on the stage 620. For example, a drill, a flat end mill, or a ball end mill can be used as the cutting tool 611. The cutting unit 610 detects the position of the tip of the cutting tool 611 using a general position detection sensor and transmits the detection result to the control unit 500. The control unit 500 uses this detection result to control the moving mechanism 630, thereby changing the relative position between the cutting tool 611 and the molded product fixed on the stage 620 and performing cutting on the molded product.

[0046] According to the second embodiment described above, the molding machine 100b includes a processing unit 600 that processes the molded product formed by the injection unit. Therefore, the processing unit 600 can improve the quality of the molded product by shaping it.

[0047] C. Third Embodiment: Figure 12 is an explanatory diagram showing the schematic configuration of the molding machine 100c in the third embodiment. In the third embodiment, the molding machine 100c is equipped with two material extrusion mechanisms 200. The configuration of each part of the molding machine 100c other than the material extrusion mechanisms is the same as in the first embodiment. Note that the material supply unit 20, the communication passage 21, and the cooling unit 70 are not shown in Figure 12.

[0048] In the third embodiment, the molding machine 100c comprises a first material extrusion mechanism 201 and a second material extrusion mechanism 202. The first material extrusion mechanism 201 and the second material extrusion mechanism 202 are arranged side by side in the X direction. The first material extrusion mechanism 201 and the second material extrusion mechanism 202 are arranged such that the vertical heights of the nozzle holes 92 of each are equal. It is preferable that the first material extrusion mechanism 201 and the second material extrusion mechanism 202 are arranged adjacent to each other. Note that the first material extrusion mechanism 201 and the second material extrusion mechanism 202 are not limited to being arranged side by side in the X direction, but may be arranged side by side in the horizontal direction.

[0049] According to the third embodiment described above, the molding machine 100c is equipped with two material extrusion mechanisms 200, and the two material extrusion mechanisms 200 are arranged side by side in the horizontal direction. Therefore, the amount of plasticizer material that can be extruded per unit time can be increased compared to when the molding machine 100c is equipped with one material extrusion mechanism 200. Thus, the productivity of molded products can be improved.

[0050] D. Other embodiments: (D-1) In the above embodiment, the cross-section of the flight portion 53 in the first cross-section is rectangular, having a first side 151 and a second side 152 parallel to the rotation axis AX2. In contrast, as shown in Figure 13, the radial end of the flight portion 53 in the first cross-section may be arc-shaped. Here, the radial direction is the direction perpendicular to the rotation axis AX2 and away from the rotation axis AX2. Also, as shown in Figure 14, the cross-section of the flight portion 53 in the first cross-section may be triangular. With such a configuration, the possibility of the material supplied from the supply port 44 getting caught between the screw 50 and the cylinder 40 can be further reduced.

[0051] (D-2) In the above embodiment, the cylinder 40 has a cooled portion 42 that is cooled by the cooling portion 70, and a heated portion 43 that is located below the cooled portion 42 and is heated by the heating portion 80. In contrast, the cylinder 40 may be formed from a single member. That is, the cylinder 40 does not have to have a cooled portion 42 and a heated portion 43.

[0052] (D-3) In the above embodiment, the supply port 44 is provided at the connection between the cooled part 42 and the heated part 43. In contrast, the supply port 44 may be provided in the cooled part 42 and not in the heated part 43.

[0053] (D-4) In the above embodiment, the screw 50 has a third portion 130 at its upper end, the outer diameter of the screw 50 being the first diameter. In contrast, the screw 50 does not have to have a third portion 130.

[0054] (D-5) In the above embodiment, the horizontal width of the screw drive unit 60 is greater than the horizontal width of the first cooling unit 71. In contrast, the horizontal width of the screw drive unit 60 does not have to be greater than the horizontal width of the first cooling unit 71.

[0055] (D-6) In the above embodiment, the communication passage 21 is connected to the cylinder 40 from an oblique upward direction. In contrast, the communication passage 21 may be connected to the cylinder 40 from a direction other than oblique upward direction.

[0056] (D-7) In the third embodiment, the molding machine 100c comprises two material extrusion mechanisms 200. In contrast, the molding machine 100c may comprise three or more material extrusion mechanisms 200. In this case, the three or more material extrusion mechanisms 200 are arranged in a horizontal line.

[0057] (D-8) The above disclosure may be implemented in the form of a material extrusion mechanism 200 rather than a molding machine 100.

[0058] E. Other forms: This disclosure is not limited to the embodiments described above, and can be implemented in various forms without departing from its spirit. For example, this disclosure can also be implemented in the following forms. The technical features in the embodiments described above that correspond to the technical features in each of the forms described below can be replaced or combined as appropriate in order to solve some or all of the problems of this disclosure, or to achieve some or all of the effects of this disclosure. Furthermore, if such technical features are not described as essential in this specification, they can be deleted as appropriate.

[0059] (1) According to a first embodiment of the present disclosure, a material extrusion mechanism is provided. The material extrusion mechanism comprises a cylinder having a feed port for supplying material and provided vertically, a screw having a helical flight portion and rotating within the cylinder about a vertical axis of rotation, a first cooling portion provided to surround a portion of the screw, a heating portion provided below the first cooling portion and surrounding a portion of the screw, and at least one nozzle for discharging the plasticized material within the cylinder, wherein at least a portion of the feed port overlaps with the first cooling portion in the horizontal direction, and the screw has a first portion having an outer diameter of the flight portion that is a first diameter, and a second portion having an outer diameter of the flight portion that is smaller than the first diameter, wherein the first portion overlaps with the heating portion in the horizontal direction, and the second portion overlaps with the first cooling portion in the horizontal direction. This configuration reduces the possibility of the material supplied from the supply port becoming trapped between the screw and the cylinder in a material extrusion mechanism where the screw rotates around a vertical axis to plasticize the material.

[0060] (2) In the above embodiment, the cylinder has a part to be cooled by the first cooling unit and a part to be heated which is located below the part to be cooled and is heated by the heating unit, and the supply port may be located at the connection between the part to be cooled and the part to be heated.

[0061] (3) In the above embodiment, the cylinder has a part to be cooled by the first cooling unit and a part to be heated which is located below the part to be cooled and heated by the heating unit, wherein the first cooling unit is a cooling passage through which a refrigerant flows, and the cooling passage may be provided above the part to be cooled and the region of the heated part that is heated by the heating unit. This configuration allows for a large vertical temperature gradient across the screw, thus reducing the possibility of material being trapped between the screw and the cylinder in a material extrusion mechanism with a short vertical screw length.

[0062] (4) In the above embodiment, the heating unit may be an electric heater.

[0063] (5) In the above embodiment, the screw drive unit is further provided above the screw and has a motor for rotating the screw, and the screw has a third portion whose outer diameter is the first diameter, and the third portion may be located at the upper end of the screw. This configuration prevents material supplied into the cylinder from entering the screw drive unit.

[0064] (6) In the above embodiment, a screw drive unit is further provided above the screw and has a motor for rotating the screw, and the horizontal width of the screw drive unit may be greater than the horizontal width of the first cooling unit. With this configuration, a motor large enough to provide the output necessary for the screw's rotation can be installed in the screw drive unit.

[0065] (7) In the above configuration, a communication passage is provided that connects the material supply unit where the material is stored with the supply port, and the communication passage may be connected to the cylinder from diagonally above.

[0066] (8) In the above embodiment, the cross-section of the flight portion in the cross-section of the screw including the rotation axis is trapezoidal in shape having a first side and a second side parallel to the rotation axis, the first side is located further from the rotation axis than the second side, the length of the first side is less than or equal to the length of the second side, and the flight portion may have a stepped shape at the boundary between the first portion and the second portion. This configuration makes it easier to transport the material downwards when the screw rotates around its axis of rotation.

[0067] (9) In the above embodiment, the end of the flight portion in the cross-section of the screw including the rotation axis is arc-shaped in the direction perpendicular to the rotation axis and away from the rotation axis, or the cross-section of the flight portion in the cross-section of the screw including the rotation axis is triangular. This configuration further reduces the possibility of material supplied from the feed port becoming trapped between the screw and the cylinder.

[0068] (10) In the above embodiment, the at least one nozzle may be two or more nozzles. This configuration allows for improved productivity of molded products compared to a system where the material extrusion mechanism has a single nozzle.

[0069] (11) A second embodiment of the present disclosure provides a molding machine which comprises at least one of the material extrusion mechanisms of the first embodiment, a material stacking section into which the material extruded from the nozzle is stacked, and a moving mechanism which changes the relative position between the material extrusion mechanism and the material stacking section, and which forms a molded product by stacking the material extruded from the nozzle. With this configuration, the material extrusion mechanism of the molding machine can have a large vertical temperature gradient in the screw, thus reducing the possibility of the material supplied from the supply port getting caught between the screw and the cylinder in a material extrusion mechanism with a short vertical screw length.

[0070] (12) In the above embodiment, a processing unit for processing the molded product may be further provided. With this configuration, the processing unit can improve the shape of the molded product, thereby enhancing the quality of the molded product.

[0071] (13) In the above embodiment, the at least one material extrusion mechanism is two or more material extrusion mechanisms, and the two or more material extrusion mechanisms may be arranged side by side in the horizontal direction. This configuration allows for improved productivity of molded products compared to when the molding machine has a single material extrusion mechanism. [Explanation of Symbols]

[0072] 20...Material supply section, 21...Communication passage, 30...Plasticizing section, 40...Cylinder, 41...Main body section, 42...Cooled section, 43...Heated section, 44...Supply port, 46...Nozzle fixing section, 47...Through hole, 50...Screw, 51...Tip section, 52...Groove section, 53...Flight section, 60...Screw drive section, 61...Drive motor, 62...Reduction gear, 63...Case, 64...Gear case section, 65...Motor case section, 66...Rotating shaft, 70...Cooling section, 71...First cooling section, 71...First cooling passage, 72...Second cooling section, 72...Second cooling passage, 73...Refrigerant supply section, 80...Heating section, 90...Discharge section, 9 1…Nozzle, 92…Nozzle hole, 93…O-ring, 100, 100b, 100c…Molding machine, 101…Molding cell, 102…Processing cell, 110…First part, 120…Second part, 130…Third part, 151…First side, 152…Second side, 200…Material extrusion mechanism, 201…First material extrusion mechanism, 202…Second material extrusion mechanism, 300…Material lamination section, 310…Molding surface, 400…Moving mechanism, 500…Control unit, 600…Processing section, 610…Cutting section, 611…Cutting tool, 620…Stage, 621…Cutting surface, 630…Moving mechanism, AX1…Central axis, AX2…Rotation axis

Claims

1. A material extrusion mechanism, A cylinder having a supply port for supplying material and positioned vertically, A screw having a spiral flight section and rotating around a rotation axis aligned vertically within the cylinder, A first cooling section is provided so as to surround a part of the screw, A heating section is provided below the first cooling section so as to surround a part of the screw, The cylinder comprises at least one nozzle for discharging the plasticized material inside the cylinder, At least a portion of the supply port overlaps with the first cooling unit in the horizontal direction. The aforementioned screw is The first portion of the flight section has an outer diameter of a first diameter, The flight portion has a second portion whose outer diameter is smaller than the first diameter, The first part overlaps with the heating section in the horizontal direction, The second portion overlaps with the first cooling unit in the horizontal direction. Material extrusion mechanism.

2. A material extrusion mechanism according to claim 1, The cylinder has a part to be cooled by the first cooling unit and a part to be heated, which is located below the part to be cooled and is heated by the heating unit. The supply port is located at the connection point between the part to be cooled and the part to be heated. Material extrusion mechanism.

3. A material extrusion mechanism according to claim 1, The cylinder has a part to be cooled by the first cooling unit and a part to be heated, which is located below the part to be cooled and is heated by the heating unit. The first cooling section is a cooling channel through which a refrigerant flows, The cooling channel is provided above the portion to be cooled and the portion to be heated that is heated by the heating portion. Material extrusion mechanism.

4. A material extrusion mechanism according to claim 1, The heating element is an electric heater. Material extrusion mechanism.

5. A material extrusion mechanism according to claim 1, The screw drive unit is further provided above the screw and has a motor for rotating the screw, The screw has a third portion whose outer diameter is the first diameter, The third portion is located at the upper end of the screw, Material extrusion mechanism.

6. A material extrusion mechanism according to claim 1, The screw drive unit is further provided above the screw and has a motor for rotating the screw, The horizontal width of the screw drive unit is greater than the horizontal width of the first cooling unit. Material extrusion mechanism.

7. A material extrusion mechanism according to claim 1, The material supply section where the material is stored is provided with a connecting passage that connects the supply port, The aforementioned connecting passage is connected to the cylinder from diagonally above. Material extrusion mechanism.

8. A material extrusion mechanism according to claim 1, The cross-section of the flight portion in the cross-section of the screw including the rotation axis is trapezoidal in shape, having a first side and a second side parallel to the rotation axis, the first side being located further from the rotation axis than the second side, and the length of the first side being less than or equal to the length of the second side. The flight portion has a stepped shape at the boundary between the first portion and the second portion. Material extrusion mechanism.

9. A material extrusion mechanism according to claim 1, In the cross-section of the flight portion of the screw including the rotation axis, the end on the radial side that is perpendicular to the rotation axis and away from the rotation axis is arc-shaped, or the cross-section of the flight portion of the screw including the rotation axis is triangular. Material extrusion mechanism.

10. A material extrusion mechanism according to claim 1, The aforementioned at least one nozzle is two or more nozzles. Material extrusion mechanism.

11. It is a molding machine, The material extrusion mechanism according to claim 1, A material lamination section in which the material discharged from the nozzle is laminated, The system includes a moving mechanism that changes the relative position between the material extrusion mechanism and the material lamination section, A molded product is formed by stacking the material discharged from the nozzle. Molding machine.

12. A molding machine according to claim 11, The system further includes a processing unit for processing the aforementioned molded product. Molding machine.

13. A molding machine according to claim 11, The aforementioned at least one material extrusion mechanism is two or more material extrusion mechanisms, The two or more material extrusion mechanisms are arranged side by side in the horizontal direction. Molding machine.

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