JP7794074B2 - Plasticizing device, injection molding system, and three-dimensional modeling system - Google Patents

Description

The present disclosure relates to a plasticization device, an injection molding system, and a three-dimensional modeling system.

Patent Document 1 discloses a powder/granular material supply system that uses a property sensor installed in the storage hopper to measure the physical property data of the powder/granular material in the storage hopper, and supplies the powder/granular material to a molding machine if the physical property data of the powder/granular material is determined to be good.

JP 2012-240246 A

When measuring the physical properties of pellet-shaped material in a hopper without contacting the material, there was a problem in that it was difficult to accurately measure the moisture content and temperature, which are values related to the viscosity of the material, depending on the orientation of the material in the hopper.

According to a first aspect of the present disclosure, a plasticizing device is provided. This plasticizing device includes a material storage unit that stores pellet-shaped material, a plasticizing unit that plasticizes at least a portion of the material supplied from the material storage unit to produce a plasticized material, a nozzle that injects the plasticized material to the outside, and a viscosity measuring unit that measures values related to the viscosity of the material present at different positions within the material storage unit without contacting the material, and determines a representative value related to the viscosity of the material within the material storage unit.

According to a second aspect of the present disclosure, there is provided an injection molding system. This injection molding system includes the plasticizing device and a mold clamping device in which a molding mold into which the plasticized material injected from the nozzle is placed.

According to a third aspect of the present disclosure, a three-dimensional modeling system is provided. This three-dimensional modeling system includes the plasticizing device and a modeling stage having a modeling surface on which the plasticized material ejected from the nozzle is deposited.

1 is an explanatory diagram showing a schematic configuration of an injection molding system according to a first embodiment. FIG. 1 is a perspective view showing a schematic configuration of an injection molding system according to a first embodiment. FIG. 3 is a cross-sectional view showing a schematic configuration of a supply adjustment unit. FIG. 3 is a cross-sectional view showing a schematic configuration of a supply adjustment unit. FIG. 2 is a cross-sectional view showing a schematic configuration of a plasticizing section. FIG. 2 is a perspective view showing a schematic configuration of a flat screw. FIG. 2 is a schematic plan view of the barrel. 1 is a calibration curve showing the relationship between the moisture content of a material and the intensity of reflected light. 3A to 3C are process diagrams illustrating the manufacturing process of a molded product by the injection molding system in the first embodiment. FIG. 10 is a perspective view showing a schematic configuration of an injection molding system according to a second embodiment. 10A to 10C are process diagrams illustrating the manufacturing process of a molded product by an injection molding system in a second embodiment. FIG. 13 is an explanatory diagram illustrating a schematic configuration of a three-dimensional printing system according to a fifth embodiment.

A. First embodiment:
FIG. 1 is an explanatory diagram showing a schematic configuration of an injection molding system 100 in this embodiment. FIG. 2 is a perspective view showing a schematic configuration of the injection molding system 100 in this embodiment. FIGS. 1 and 2 show arrows representing mutually orthogonal X, Y, and Z directions. The X and Y directions are parallel to a horizontal plane. The Z direction is parallel to the vertical direction. The X, Y, and Z directions in FIGS. 1 and 2 and the X, Y, and Z directions in other figures indicate the same directions. When specifying a direction, positive and negative signs are used in combination to indicate the direction, with "+" indicating the positive direction indicated by the arrow and "-" indicating the negative direction opposite to the direction indicated by the arrow.

The injection molding system 100 comprises a plasticizing device 10, a mold clamping device 20, and an inspection device 30. The injection molding system 100 molds a molded product by injecting the plasticized material produced by the plasticizing device 10 into a molding die 21 arranged in the mold clamping device 20. The operation of the plasticizing device 10 and the mold clamping device 20 is controlled by a control unit 180 provided in the plasticizing device 10. The inspection device 30 inspects the quality of the molded product formed by injecting the plasticized material into the molding die 21.

The mold clamping unit 20 comprises a fixed part 24, a mold drive part 25, and a ball screw 26.

The molding die 21 is composed of a fixed die 22 and a movable die 23. The fixed die 22 is attached to the plasticizing device 10. The movable die 23 is attached to a fixed portion 24. The movable die 23 is movable forward and backward relative to the fixed die 22 in the clamping direction by the clamping device 20. Here, the clamping direction is the -Y direction. The plasticized material produced by the plasticizing device 10 is injected into a cavity defined by the fixed die 22 and the movable die 23. The molding die 21 may be made of metal, resin, or ceramic. A metal molding die 21 is also called a metal mold.

The mold drive unit 25 is composed of a motor, gears, etc., and is connected to the movable mold 23 via a ball screw 26. The mold drive unit 25 is driven under the control of the control unit 180. The ball screw 26 transmits the power generated by the drive of the mold drive unit 25 to the movable mold 23. The mold clamping unit 20 moves the movable mold 23 using the mold drive unit 25 and ball screw 26, thereby moving the movable mold 23 relative to the fixed mold 22 and opening and closing the forming mold 21.

The plasticizing device 10 includes a material storage unit 110, a viscosity measurement unit 120, a retention time measurement unit 130, a supply adjustment unit 140, a plasticizing unit 150, a nozzle 160, a gas detection unit 170, and a control unit 180.

The material storage section 110 stores the pellet-shaped molded product material. The material storage section 110 is preferably made of a material that transmits infrared rays. Examples of materials used for molded products include thermoplastic resins such as polypropylene resin (PP), polyethylene resin (PE), and polyacetal resin (POM). The material storage section 110 is also called a hopper.

The viscosity measuring unit 120 measures the viscosity values of the material present at different positions within the material storage unit 110 without contacting the material, and determines a representative value for the viscosity values of the material within the material storage unit 110. In this embodiment, the viscosity value of the material is the water content of the material. In this embodiment, an average value is determined as the representative value. The viscosity measuring unit 120 is provided on the outer periphery of the material storage unit 110. Details of the viscosity measuring unit 120 will be described later.

The storage time measurement unit 130 measures the time that the material is stored in the material storage unit 110. The storage time measurement unit 130 is, for example, a timer that measures time. The time that the material is stored in the material storage unit 110 is measured, for example, when the material is supplied to the material storage unit 110, by the user starting time measurement using the timer.

The supply adjustment unit 140 is located on the -Z direction side of the material storage unit 110. The supply adjustment unit 140 adjusts the amount of material supplied from the material storage unit 110 to the plasticization unit 150. Details of the supply adjustment unit 140 will be described later.

The plasticizing unit 150 plasticizes at least a portion of the material supplied from the material storage unit 110 to produce a plasticized material. In this specification, "plasticization" is a concept that includes melting, and refers to changing from a solid to a fluid state. Specifically, in the case of a material that undergoes glass transition, plasticization refers to raising the temperature of the material to or above the glass transition point. In the case of a material that does not undergo glass transition, plasticization refers to raising the temperature of the material to or above the melting point. Details of the plasticizing unit 150 will be provided later.

The nozzle 160 injects the plasticized material produced in the plasticizing section 150 to the outside. In this embodiment, the nozzle 160 injects the plasticized material produced in the plasticizing section 150 into the cavity of the mold 21.

The gas detection unit 170 detects gases generated when the material is plasticized in the plasticization unit 150. The gas detection unit 170 is, for example, a gas detector that detects the gas to be detected and notifies the presence of the gas to be detected. The gas detection unit 170 detects gases that flow back from the plasticization unit 150 to the material storage unit 110.

The control unit 180 is configured as a computer having a CPU 181 and a memory unit 186. The CPU 181 has one or more processors and a main memory unit. The memory unit 186 is configured as an auxiliary memory unit such as a hard disk drive. Note that the control unit 180 may also be configured as a circuit.

The CPU 181 includes a determination unit 182. The determination unit 182 is realized by the CPU 181 executing a program stored in the memory unit 186.

The determination unit 182 acquires the value related to the viscosity of the material measured by the viscosity measurement unit 120 and determines whether the value related to the viscosity of the material measured by the viscosity measurement unit 120 is below a predetermined threshold value.

The memory unit 186 stores a predetermined threshold value for the viscosity of the material. In this embodiment, the predetermined threshold value for the viscosity of the material is the upper threshold value for the moisture content of the material. The memory unit 186 also stores the inspection results of the molded product by the inspection device 30 and the viscosity value of the material used to mold the molded product, in association with each other.

The control unit 180 is connected to the inspection device 30, the display unit 510, and the alarm unit 520. The control unit 180 obtains the time that the material has been stored in the material storage unit 110 from the storage time measurement unit 130, and displays the time that the material has been stored in the material storage unit 110 on the display unit 510. Furthermore, if gas is detected by the gas detection unit 170, the control unit 180 activates the alarm unit 520. The alarm unit 520 is, for example, an alarm.

Figures 3 and 4 are cross-sectional views showing the general configuration of the supply adjustment unit 140. The supply adjustment unit 140 includes a guide case 210, a connection path 220, a material cutting plate 230, an air cylinder 240, a piston rod 250, a first air pressure port 260, and a second air pressure port 270.

The guide case 210 is a roughly rectangular parallelepiped member with an internal cavity. The guide case 210 has a material inlet 211 and a material outlet 212. The material inlet 211 is a hole provided on the top surface of the guide case 210 to connect the material storage section 110 and the guide case 210. The material outlet 212 is a hole provided on the bottom surface of the guide case 210 to connect the guide case 210 and the connection path 220.

The connection path 220 is a hollow member that connects the guide case 210 and the plasticizing section 150.

The material cutting plate 230 is a plate-shaped member provided inside the guide case 210. The material cutting plate 230 has a cutting hole 231 formed in the Z direction.

The air cylinder 240 is provided on the -Z direction side of the guide case 210. The air cylinder 240 is a roughly cylindrical member with an internal cavity.

A portion of the piston rod 250 is located inside the air cylinder 240, and one end is fixed to the material cutting plate 230. The piston rod 250 has a partition plate 251. The partition plate 251 is a disk-shaped member located on the outer periphery of the portion of the piston rod 250 that is located inside the air cylinder 240. The partition plate 251 divides the space inside the air cylinder 240 into two spaces in the X direction.

The first air pressure port 260 and the second air pressure port 270 are located on the -Z direction side of the air cylinder 240. The first air pressure port 260 is located on the +X direction side of the partition plate 251, and the second air pressure port 270 is located on the -X direction side of the partition plate 251. The first air pressure port 260 and the second air pressure port 270 are each connected to a pipe that supplies compressed air via a solenoid valve (not shown). When the control unit 180 opens and closes the solenoid valve, compressed air is supplied to the inside of the air cylinder 240 via the first air pressure port 260 or the second air pressure port 270.

When compressed air is supplied to the inside of the air cylinder 240 through the first air pressure port 260, the piston rod 250 moves in the -X direction. At this time, the material feeding plate 230 moves in the -X direction in conjunction with the piston rod 250. When compressed air is supplied to the inside of the air cylinder 240 through the second air pressure port 270, the piston rod 250 moves in the +X direction. At this time, the material feeding plate 230 moves in the +X direction in conjunction with the piston rod 250. Figure 3 shows the case where the material feeding plate 230 moves in the -X direction, and Figure 4 shows the case where the material feeding plate 230 moves in the +X direction. As described above, the material feeding plate 230 moves back and forth in the X direction inside the guide case 210.

When the material dispensing plate 230 moves in the -X direction, the material storage section 110 and the connection path 220 communicate with each other via the dispensing hole 231. When the material dispensing plate 230 moves in the +X direction, the material storage section 110 and the connection path 220 are closed by the material dispensing plate 230 to prevent communication between them. Therefore, as the material dispensing plate 230 moves in the -X direction and then in the +X direction, a portion of the material stored in the material storage section 110 is introduced into the connection path 220. The amount of material introduced into the connection path 220 is controlled by the control unit 180 controlling the number of times the material dispensing plate 230 moves back and forth in the X direction.

Figure 5 is a cross-sectional view showing the schematic configuration of the plasticizing unit 150. The plasticizing unit 150 includes a flat screw 310, a barrel 320, a heating unit 330, and a suction delivery unit 340.

The flat screw 310 is housed in a space surrounded by the screw case 311 and the barrel 320. The flat screw 310 is connected to the drive shaft 312. The drive motor 313 applies a driving force to the drive shaft 312, causing the flat screw 310 to rotate integrally with the drive shaft 312. The rotation axis RX of the flat screw 310 coincides with the axis of the drive shaft 312. The axial direction of the rotation axis RX of the flat screw 310 is along the Y direction. The rotation speed of the flat screw 310 is controlled by the control unit 180 controlling the rotation speed of the drive motor 313. The flat screw 310 may be driven by the drive motor 313 via a reducer. The flat screw 310 is also called a rotor or a screw.

The barrel 320 is installed on the +Y direction side of the flat screw 310. The barrel 320 is housed in a space surrounded by the barrel case 321 and the flat screw 310. A communication hole 322 is formed in the center of the barrel 320. The communication hole 322 is connected to a flow path 323. The suction and delivery cylinder 341 and nozzle 160, described below, are connected to the flow path 323. A check valve 324 is provided in the flow path 323, upstream of the suction and delivery cylinder 341. The check valve 324 prevents backflow of the plasticized material from the nozzle 160 side to the flat screw 310 side.

The heating unit 330 is provided inside the barrel 320. The heating unit 330 heats the barrel 320 and the suction delivery cylinder 341. The temperature of the heating unit 330 is controlled by the control unit 180. The heating unit 330 is, for example, a heater.

Figure 6 is a perspective view showing the schematic configuration of the flat screw 310. The flat screw 310 has a generally cylindrical shape whose length along the rotation axis RX is shorter than its length perpendicular to the rotation axis RX. A spiral groove 317 is formed around the central portion 316 on the groove-forming surface 315 of the flat screw 310, which faces the barrel 320. The groove 317 is connected to the material inlet 314 formed on the side of the flat screw 310. Material supplied from the connection path 220 of the supply adjustment unit 140 is supplied to the groove 317 through the material inlet 314. The grooves 317 are separated by ridge portions 318. Figure 6 shows an example in which three grooves 317 are formed, but the number of grooves 317 may be one or more. The groove 317 is not limited to a spiral shape; it may also be a spiral or involute curve shape, or a shape extending in an arc from the central portion 316 to the outer periphery.

Figure 7 is a schematic plan view of the barrel 320. The barrel 320 has an opposing surface 325 that faces the groove-forming surface 315 of the flat screw 310 in the direction along the drive shaft 312. A communication hole 322 that communicates with the flow path 323 is formed in the center of the opposing surface 325. The opposing surface 325 is formed with a plurality of guide grooves 326 that are connected to the communication hole 322 and extend spirally from the communication hole 322 toward the outer periphery. Note that the guide grooves 326 do not necessarily have to be provided on the barrel 320. Furthermore, the guide grooves 326 do not necessarily have to be connected to the communication hole 322.

The material supplied to the groove 317 of the flat screw 310 is plasticized between the flat screw 310 and the barrel 320 by the rotation of the flat screw 310 and the heating of the heating section 330. As the flat screw 310 rotates, the material flows along the groove 317 and guide groove 326, and is guided to the center section 316 of the flat screw 310. The material that flows into the center section 316 flows out into the communication hole 322 located in the center of the barrel 320.

As shown in FIG. 5, the suction delivery unit 340 comprises a suction delivery cylinder 341, a plunger 342, and a plunger drive unit 343. The suction delivery unit 340 has the function of injecting the plasticized material in the suction delivery cylinder 341 into the cavity of the mold 21. The suction delivery cylinder 341 is a cylindrical member connected to the flow path 323. The plunger 342 is a roughly cylindrical member, a portion of which is provided inside the suction delivery cylinder 341. The plunger 342 moves inside the suction delivery cylinder 341 in a direction away from the flow path 323 to suck and measure the plasticized material into the suction delivery cylinder 341. The plunger 342 then moves inside the suction delivery cylinder 341 in a direction toward the flow path 323 to deliver the plasticized material into the flow path 323. The plasticized material delivered to flow path 323 is pressure-fed to nozzle 160 and injected from nozzle 160 into the cavity of mold 21. Plunger 342 is driven by plunger driver 343, which is composed of a motor. The injection amount, injection speed, and injection pressure of the plasticized material injected from nozzle 160 are controlled by control unit 180, which controls plunger driver 343.

In this embodiment, the viscosity measurement unit 120 includes a moisture content measurement unit 121. The moisture content measurement unit 121 measures the moisture content of materials present at different positions within the material storage unit 110 without contacting the materials. As shown in FIG. 2, the moisture content measurement unit 121 includes a first moisture content sensor 122a, a second moisture content sensor 122b, and a third moisture content sensor 122c. The first moisture content sensor 122a, the second moisture content sensor 122b, and the third moisture content sensor 122c each optically measure the moisture content of materials present at different positions within the material storage unit 110. Hereinafter, when the moisture content sensors are referred to interchangeably, they will simply be referred to as moisture content sensors 122. In this embodiment, the moisture content measurement unit 121 is not limited to three moisture content sensors 122, and may include two moisture content sensors 122, or four or more moisture content sensors 122. The moisture content sensors 122 may be arranged in an array around the outer periphery of the material storage section 110.

The moisture content sensor 122 is a device that measures the moisture content of the material in the material storage section 110 through spectroscopic analysis. The moisture content sensor 122 is, for example, a near-infrared spectrometer. The moisture content sensor 122 irradiates the material in the material storage section 110 with near-infrared light and measures the light that is not absorbed by the material and is reflected. The moisture content measurement unit 121 determines the reflected light intensity of near-infrared light with wavelengths around 1900 nm to 1940 nm by measuring the light reflected when the material is irradiated with near-infrared light with wavelengths around 1900 nm to 1940 nm. Here, near-infrared light with wavelengths around 1900 nm to 1940 nm is also referred to as the moisture absorption band. The moisture content measurement unit 121 calculates the average value of the reflected light intensity of the moisture absorption band of the material in the material storage section 110 from the reflected light intensities of the moisture absorption band of the material present at different positions in the material storage section 110 measured by multiple moisture content sensors 122. The moisture content measuring unit 121 may also irradiate the material with near-infrared light of a wavelength outside the moisture absorption band and measure the reflected light.

Figure 8 shows a calibration curve indicating the relationship between the moisture content of a material and the reflected light intensity. In the graph shown in Figure 8, the horizontal axis represents the moisture content of the material in the material storage section 110, and the vertical axis represents the average value of the reflected light intensity of the moisture absorption band of the material in the material storage section 110. The calibration curve shown in Figure 8 is created by the moisture content measurement section 121 measuring the material stored in the material storage section 110, whose moisture content is known in advance, and determining the average value of the reflected light intensity of the moisture absorption band. The moisture content measurement section 121 creates the above-mentioned calibration curve before the injection molding system 100 uses the material in the material storage section 110 to mold a molded product.

Figure 9 is a process diagram illustrating the manufacturing process of a molded product using the injection molding system 100 in the first embodiment.

First, in step S10 of Figure 9, the material used to form the molded product is dried. The material is dried, for example, using a dryer.

Next, in step S20 of Figure 9, the dried material is poured into the material storage section 110.

Next, in step S30 of FIG. 9, the time the material has been stored in the material storage unit 110, measured by the storage time measurement unit 130, is displayed on the display unit 510.

Next, in step S40 of FIG. 9, the moisture content measurement unit 121 measures the moisture content of the material in the material storage unit 110. Specifically, the moisture content measurement unit 121 calculates the average value of the reflected light intensity of the moisture absorption band of the material in the material storage unit 110, and calculates the average moisture content of the material in the material storage unit 110 using the calibration curve shown in FIG. 8.

Next, in step S50 of FIG. 9 , the determination unit 182 compares the average moisture content of the material measured by the moisture content measurement unit 121 with the upper moisture content threshold. If the determination unit 182 determines that the average moisture content of the material measured by the moisture content measurement unit 121 exceeds the upper moisture content threshold, the material in the material storage unit 110 is dried again. If the determination unit 182 determines that the average moisture content of the material measured by the moisture content measurement unit 121 is below the upper moisture content threshold, the material is transferred from the material storage unit 110 to the plasticization unit 150 via the supply adjustment unit 140.

Next, in step S60 of Figure 9, the material transferred to the plasticizing unit 150 is plasticized.

Next, in step S70 of FIG. 9, if the gas detection unit 170 detects gas generated when the material is plasticized, the notification unit 520 notifies the generation of gas in step S80 of FIG. 9.

Next, in step S90 of Figure 9, the suction delivery unit 340 injects the plasticized material into the cavity of the mold 21.

Next, in step S100 of Figure 9, the molded product is inspected by the inspection device 30.

Finally, in step S110 of Figure 9, the inspection results of the molded product by the inspection device 30 and the moisture content of the material used to form the molded product are associated and stored in the memory unit 186.

The series of steps from step S60 to step S110 in Figure 9 described above is repeated until molding of a predetermined number of molded products is completed.

The material storage unit 110 may also have a device for drying the material stored therein. If the material storage unit 110 has a device for drying the material stored therein, and the determination unit 182 determines that the average moisture content of the material measured by the moisture content measurement unit 121 is below the upper moisture content threshold, the material may be dried in the material storage unit 110.

According to the injection molding system 100 of the first embodiment described above, the moisture content measuring unit 121 calculates the average value of the reflected light intensity of the moisture absorption band of the material in the material storage unit 110 from the reflected light intensity of the moisture absorption band of the material present at different positions in the material storage unit 110 measured by the multiple moisture content sensors 122, and calculates the average value of the moisture content of the material in the material storage unit 110 using a calibration curve showing the relationship between the moisture content of the material and the reflected light intensity. This makes it possible to more accurately measure the moisture content of the material in the material storage unit 110, regardless of the orientation of the material in the material storage unit 110.

In addition, the injection molding system 100 of the first embodiment uses only materials for molding that are determined by the determination unit 182 to have an average moisture content measured by the moisture content measurement unit 121 that is below the upper moisture content threshold. This prevents air bubbles from forming in the molded product, resulting in poor appearance, and reduces the production of defective products due to insufficient filling of the plasticized material into the cavity of the mold 21.

B. Second embodiment:
FIG. 10 is a perspective view showing a schematic configuration of an injection molding system 100a according to a second embodiment. In this embodiment, values related to the viscosity of a material are the moisture content and temperature of the material. In the second embodiment, the viscosity measurement unit 120a includes a moisture content measurement unit 121 and a temperature measurement unit 126. The temperature measurement unit 126 measures the temperature of the material present in a predetermined region within the material storage unit 110 without contacting the material. As shown in FIG. 10, the temperature measurement unit 126 includes a first temperature sensor 127a, a second temperature sensor 127b, and a third temperature sensor 127c. The first temperature sensor 127a, the second temperature sensor 127b, and the third temperature sensor 127c optically measure the temperature of the material present at different positions within the material storage unit 110. Hereinafter, when the temperature sensors are referred to interchangeably, they will simply be referred to as temperature sensor 127. In this embodiment, the temperature measurement unit 126 is not limited to having three temperature sensors 127, but may have two temperature sensors 127, or four or more temperature sensors 127. The temperature sensors 127 may be arranged in an array around the outer periphery of the material storage unit 110.

The temperature sensor 127 is a device that measures the temperature of the material in the material storage section 110 without coming into contact with the material. The temperature sensor 127 is, for example, a radiation thermometer. The temperature sensor 127 measures the temperature of the material by measuring the intensity of infrared rays or visible light emitted from the material. The temperature measurement section 126 calculates the average temperature of the material in the material storage section 110 from the temperatures of the material present at different positions in the material storage section 110 measured by multiple temperature sensors 127.

In the second embodiment, the memory unit 186 stores a lower threshold value for the moisture content of the material and a lower threshold value for the temperature of the material as predetermined threshold values for the viscosity of the material.

Figure 11 is a process diagram illustrating the manufacturing process of a molded product using the injection molding system 100a in the second embodiment.

In step S200 of FIG. 11, the moisture content measurement unit 121 measures the average moisture content of the material in the material storage unit 110. Furthermore, the temperature measurement unit 126 measures the average temperature of the material in the material storage unit 110.

Next, in step S210 of FIG. 11, the determination unit 182 compares the average moisture content of the material measured by the moisture content measurement unit 121 with the lower moisture content threshold. If the determination unit 182 determines that the average moisture content of the material measured by the moisture content measurement unit 121 is below the lower moisture content threshold, a viscosity adjustment process is executed.

If the determination unit 182 determines in step S210 of FIG. 11 that the average moisture content of the material measured by the moisture content measurement unit 121 exceeds the lower moisture content threshold, then in step S220 of FIG. 11, the determination unit 182 compares the average material temperature measured by the temperature measurement unit 126 with the lower temperature threshold. If the determination unit 182 determines that the average material temperature measured by the temperature measurement unit 126 is below the lower temperature threshold, viscosity adjustment processing is executed. If the determination unit 182 determines that the average material temperature measured by the temperature measurement unit 126 exceeds the lower temperature threshold, viscosity adjustment processing is not executed.

If the determination unit 182 determines that the average moisture content of the material measured by the moisture content measurement unit 121 is below the lower moisture content threshold, or if the average temperature of the material measured by the temperature measurement unit 126 is below the lower temperature threshold, the viscosity adjustment process is executed in step S230 of FIG. 11. In the viscosity adjustment process of the second embodiment, the control unit 180 increases the rotation speed of the flat screw 310 compared to when the determination unit 182 determines that the average moisture content of the material measured by the moisture content measurement unit 121 exceeds the lower moisture content threshold and that the average temperature of the material measured by the temperature measurement unit 126 exceeds the lower temperature threshold.

In the injection molding system 100a of the second embodiment described above, if the judgment unit 182 determines that either the average moisture content or temperature of the material in the material storage unit 110 measured by the viscosity measurement unit 120a is below its lower threshold, a viscosity adjustment process is executed. If the average moisture content or temperature of the material in the material storage unit 110 is below its lower threshold, the viscosity of the plasticized material increases. Therefore, by executing the viscosity adjustment process and increasing the rotation speed of the flat screw 310, the viscosity of the plasticized material can be reduced.

C. Third embodiment:
The configuration of the injection molding system 100a in the third embodiment is the same as that in the second embodiment. The manufacturing process of a molded product by the injection molding system 100a in the third embodiment is the same as the manufacturing process of a molded product by the injection molding system 100a in the second embodiment shown in Figure 11, except for the viscosity adjustment process.

If the determination unit 182 determines that the average moisture content of the material measured by the moisture content measurement unit 121 is below the lower moisture content threshold, or if the average temperature of the material measured by the temperature measurement unit 126 is below the lower temperature threshold, a viscosity adjustment process is executed in step S230 of FIG. 11. In the third embodiment, in the viscosity adjustment process shown in step S230 of FIG. 11, the control unit 180 increases the temperature of the barrel 320 compared to when the determination unit 182 determines that the average moisture content of the material measured by the moisture content measurement unit 121 exceeds the lower moisture content threshold and that the average temperature of the material measured by the temperature measurement unit 126 exceeds the lower temperature threshold.

In the injection molding system 100a of the third embodiment described above, if the judgment unit 182 determines that either the moisture content or the average temperature of the material in the material storage unit 110 measured by the viscosity measurement unit 120 is below its lower threshold, a viscosity adjustment process is executed, and the temperature of the barrel 320 is increased, thereby reducing the viscosity of the plasticized material.

D. Fourth embodiment:
The configuration of the injection molding system 100a in the fourth embodiment is the same as that in the second embodiment. The manufacturing process of a molded product by the injection molding system 100a in the fourth embodiment is the same as the manufacturing process of a molded product by the injection molding system 100a in the second embodiment shown in Figure 11, except for the viscosity adjustment process.

If the determination unit 182 determines that the average moisture content of the material measured by the moisture content measurement unit 121 is below the lower moisture content threshold, or if the average temperature of the material measured by the temperature measurement unit 126 is below the lower temperature threshold, a viscosity adjustment process is executed in step S230 of FIG. 11 . In the fourth embodiment, in the viscosity adjustment process shown in step S230 of FIG. 11 , the control unit 180 increases the injection speed of the plunger 342 compared to when the determination unit 182 determines that the average moisture content of the material measured by the moisture content measurement unit 121 exceeds the lower moisture content threshold and that the average temperature of the material measured by the temperature measurement unit 126 exceeds the lower temperature threshold. Specifically, the control unit 180 increases the speed at which the plunger 342 moves to deliver the plasticized material toward the nozzle 160.

In the injection molding system 100a of the fourth embodiment described above, if the judgment unit 182 determines that either the average moisture content or temperature of the material in the material storage unit 110 measured by the viscosity measurement unit 120 is below its lower threshold, a viscosity adjustment process is performed and the injection speed of the plunger 342 is increased, making it easier to inject the plasticized material into the cavity of the mold 21 even if the viscosity of the plasticized material is high.

E. Fifth embodiment:
12 is an explanatory diagram showing a schematic configuration of a three-dimensional modeling system 400 according to the fifth embodiment. The three-dimensional modeling system 400 includes a plasticizing device 10b, a modeling stage 410, and a moving mechanism 420.

The plasticizing device 10b includes a material storage unit 110, a viscosity measurement unit 120, a retention time measurement unit 130, a supply adjustment unit 140, a plasticizing unit 150b, a nozzle 160, a gas detection unit 170, and a control unit 180b. The plasticizing device 10b in the fifth embodiment is similar to the plasticizing device 10 in the first embodiment, except for the configuration of the plasticizing unit 150b.

The plasticizing unit 150b includes a flat screw 310, a barrel 320, a heating unit 330, and a suction delivery unit 340. In this embodiment, instead of a check valve 324, a valve 430 is provided in the flow path 323 connecting the communication hole 322 of the barrel 320 and the nozzle 160, which switches the amount of plasticizing material discharged from the nozzle 160 or whether or not it is discharged. The valve 430 is driven under the control of the control unit 180b. The rest of the configuration of the plasticizing unit 150b is the same as that of the plasticizing unit 150 in the first embodiment.

The modeling stage 410 faces the nozzle 160. The plasticized material ejected from the nozzle 160 is deposited on a modeling surface 411 on the stage. In this embodiment, the modeling surface 411 is aligned horizontally. The modeling stage 410 is supported by a movement mechanism 420.

The movement mechanism 420 changes the relative position between the nozzle 160 and the modeling stage 410. In this embodiment, the movement mechanism 420 changes the relative position between the nozzle 160 and the modeling stage 410 by moving the modeling stage 410. In this embodiment, the movement mechanism 420 is configured as a three-axis positioner that moves the modeling stage 410 in three axial directions (X, Y, and Z) using power generated by three motors. Each motor is driven under the control of the control unit 180. Note that the movement mechanism 420 may be configured to change the relative position between the nozzle 160 and the modeling stage 410 by moving the plasticization device 10b without moving the modeling stage 410. Alternatively, the movement mechanism 420 may be configured to change the relative position between the nozzle 160 and the modeling stage 410 by moving both the modeling stage 410 and the plasticization device 10b.

Under the control of the control unit 180b, the three-dimensional modeling system 400 discharges plasticized material from the nozzle 160 while changing the relative position between the nozzle 160 and the modeling stage 410, thereby stacking layers of plasticized material onto the modeling stage 410 to form a three-dimensional object of the desired shape. When the control unit 180b uses the valve 430 to temporarily stop the discharge of plasticized material from the nozzle 160, it drives the plunger 342 provided in the suction feed unit 340 to suck the plasticized material around the nozzle into the suction feed cylinder 341. When discharge resumes, it drives the plunger 342 to pressure-feed the plasticized material from the suction feed cylinder 341 toward the nozzle 160.

The viscosity measurement unit 120 includes a moisture content measurement unit 121. As in the first embodiment, the moisture content measurement unit 121 calculates the average value of the reflected light intensity of the moisture absorption band of the material in the material storage unit 110 from the reflected light intensity of the moisture absorption band of the material present at different positions in the material storage unit 110 measured by multiple moisture content sensors 122, and calculates the average moisture content of the material in the material storage unit 110 using a calibration curve showing the relationship between the moisture content of the material and the reflected light intensity.

The determination unit 182 compares the average moisture content of the material measured by the moisture content measurement unit 121 with the upper moisture content threshold. If the determination unit 182 determines that the average moisture content of the material measured by the moisture content measurement unit 121 exceeds the upper moisture content threshold, the material in the material storage unit 110 is dried again.

The three-dimensional printing system 400 of the fifth embodiment described above has a moisture content measuring unit 121, just like the first embodiment, which measures the average moisture content of the material in the material storage unit 110. Therefore, the moisture content of the material in the material storage unit 110 can be measured more accurately, regardless of the orientation of the material in the material storage unit 110.

In this embodiment, the viscosity measurement unit 120 may have a temperature measurement unit 126. As in the second, third, and fourth embodiments, the temperature measurement unit 126 calculates the average temperature of the material in the material storage unit 110 from the temperatures of the material present at different positions in the material storage unit 110 measured by multiple temperature sensors 127. Furthermore, as in the second, third, and fourth embodiments, the memory unit 186 of the control unit 180b may store a lower limit threshold for the moisture content of the material and a lower limit threshold for the temperature of the material as predetermined thresholds for values related to the viscosity of the material.

In this embodiment, if the determination unit 182 determines that either the average moisture content or the average temperature of the material in the material storage unit 110 measured by the viscosity measurement unit 120 is below its lower threshold, the viscosity adjustment process of the second embodiment, the viscosity adjustment process of the third embodiment, or the viscosity adjustment process of the fourth embodiment may be executed. That is, the control unit 180b may increase the rotational speed of the flat screw 310, increase the temperature of the barrel 320, or increase the injection speed of the plunger 342 compared to when the determination unit 182 determines that the average moisture content of the material measured by the moisture content measurement unit 121 exceeds the lower threshold moisture content and that the average temperature of the material measured by the temperature measurement unit 126 exceeds the lower threshold temperature. If the control unit 180b increases the rotational speed of the flat screw 310, it may control the supply adjustment unit 140 to increase the amount of material supplied from the material storage unit 110 to the plasticization unit 150 per unit time.

F. Other Embodiments:
(F-1) In the first embodiment, the value related to the viscosity of the material may be the temperature of the material. When the value related to the viscosity of the material is the temperature of the material, the viscosity measuring unit 120 may be equipped with the temperature measuring unit 126 described in the second embodiment, and the memory unit 186 may pre-store a lower threshold value of the material temperature as a predetermined threshold value of the viscosity of the material. When the material is dried by heating, if the determination unit 182 determines that the average value of the material temperature measured by the temperature measuring unit 126 is below the lower threshold value of the temperature, the material in the material storage unit 110 may be dried again.

(F-2) In the above embodiment, the moisture content measuring unit 121 may be equipped with a single moisture content sensor 122 instead of multiple moisture content sensors 122. If the moisture content measuring unit 121 is equipped with a single moisture content sensor 122, the single moisture content sensor 122 may be moved to determine the reflected light intensity of the moisture absorption band of the material located at multiple locations within the material storage unit 110, thereby determining the average value of the reflected light intensity of the moisture absorption band of the material within the material storage unit 110, and using a calibration curve to determine the average moisture content of the material within the material storage unit 110. The moisture content sensor 122 may be moved by the user or by the device.

(F-3) In the above embodiment, the temperature measurement unit 126 may be equipped with a single temperature sensor 127 instead of multiple temperature sensors 127. If the temperature measurement unit 126 is equipped with a single temperature sensor 127, the single temperature sensor 127 may be moved to measure the temperatures of materials located at multiple locations within the material storage unit 110, and the average temperature of the material within the material storage unit 110 may be calculated. The temperature sensor 127 may be moved by the user or by the device.

(F-4) In the above embodiment, the temperature measurement unit 126 may measure the average temperature of material located within a predetermined range in the material storage unit 110 using a single temperature sensor 127. The temperature sensor 127 may be, for example, a thermograph.

(F-5) In the above embodiment, if the rotation speed of the flat screw 310 is slowed, the control unit 180 may control the supply adjustment unit 140 to reduce the amount of material supplied from the material storage unit 110 to the plasticization unit 150 per unit time.

(F-6) In the above embodiment, the viscosity measuring unit 120 may, for example, determine the maximum, minimum, or median value of the viscosity of the material in the material storage unit 110, rather than the average value of the viscosity of the material in the material storage unit 110. In other words, if the viscosity measuring unit 120 includes a moisture content measuring unit 121, the moisture content measuring unit 121 may, for example, determine the maximum, minimum, or median value of the moisture content of the material in the material storage unit 110, rather than the average value of the moisture content of the material in the material storage unit 110. If the viscosity measuring unit 120 includes a temperature measuring unit 126, the temperature measuring unit 126 may, for example, determine the maximum, minimum, or median value of the temperature of the material in the material storage unit 110, rather than the average value of the temperature of the material in the material storage unit 110.

(F-7) In the above embodiment, the plasticizer 10 may not include some or all of the retention time measurement unit 130, the supply adjustment unit 140, and the gas detection unit 170.

G. Other Forms:
The present disclosure is not limited to the above-described embodiments and can be realized in various forms without departing from the spirit thereof. For example, the present disclosure can also be realized in the following forms. The technical features in the above embodiments corresponding to the technical features in each form described below can be appropriately replaced or combined to solve some or all of the problems of the present disclosure or to achieve some or all of the effects of the present disclosure. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted.

(1) According to one aspect of the present disclosure, a plasticizing device is provided. This plasticizing device includes a material storage section that stores pellet-shaped material; a plasticizing section that plasticizes at least a portion of the material supplied from the material storage section to produce a plasticized material; a nozzle that injects the plasticized material to the outside; and a viscosity measuring section that measures values related to the viscosity of the material present at different positions in the material storage section without contacting the material and determines a representative value related to the viscosity of the material in the material storage section. This aspect allows for more accurate measurement of the viscosity of the material in the material storage section regardless of the orientation of the material in the material storage section.

(2) In the above embodiment, the viscosity measuring unit may optically measure values related to the viscosity of the material present at different positions within the material storage unit.

(3) In the above embodiment, a storage time measurement unit may be provided that measures the time the material is stored in the material storage unit. According to this embodiment, the user can know the time the material has been stored in the material storage unit.

(4) In the above embodiment, a gas detection unit may be provided that detects gas generated when the material is plasticized. This embodiment allows the user to know that gas has been generated when the material is plasticized.

(5) In the above embodiment, the apparatus further includes a supply adjustment unit that adjusts the amount of material supplied from the material storage unit to the plasticizing unit, and a control unit. The plasticizing unit includes a rotating flat screw having a groove-forming surface with grooves formed therein, a barrel having an opposing surface facing the groove-forming surface and having communication holes formed in the opposing surface that communicate with the nozzle, and a heating unit that heats the material supplied between the flat screw and the barrel. When the rotation speed of the flat screw is slowed, the control unit may control the supply adjustment unit to reduce the amount of material supplied per unit time from the material storage unit to the plasticizing unit. According to this embodiment, when the rotation speed of the flat screw is slowed, clogging of the material can be prevented when the material is transferred from the material storage unit to the plasticizing unit.

(6) In the above embodiment, a determination unit may be provided that determines whether the value related to the viscosity of the material measured by the viscosity measurement unit is below a predetermined threshold. According to this embodiment, it is possible to determine whether the production of defective products can be suppressed when molding products using the material in the material storage unit.

(7) In the above embodiment, a control unit is provided, and the plasticizing unit includes a rotating flat screw having a groove forming surface on which grooves are formed, a barrel having an opposing surface facing the groove forming surface and having communication holes formed in the opposing surface that communicate with the nozzle, and a heating unit that heats the material supplied between the flat screw and the barrel, and the control unit may increase the rotation speed of the flat screw or the temperature of the barrel when the determining unit determines that the value related to the viscosity of the material is below the predetermined threshold value, compared to when the value related to the viscosity of the material is equal to or greater than the predetermined threshold value. According to this embodiment, the viscosity of the plasticizing material can be reduced when the viscosity of the plasticizing material is high.

(8) In the above embodiment, the device includes a flow path through which the plasticized material flows, a suction and delivery cylinder connected to the flow path, a plunger movably disposed within the suction and delivery cylinder for sucking the plasticized material into the suction and delivery cylinder or delivering the plasticized material sucked into the suction and delivery cylinder toward the nozzle, and a control unit; and the control unit may increase the injection speed of the plunger when the determination unit determines that the value related to the viscosity of the material is below the predetermined threshold value compared to when the value related to the viscosity of the material is equal to or greater than the predetermined threshold value. According to this embodiment, even when the viscosity of the plasticized material is high, it is easier to inject the plasticized material from the nozzle into the cavity of the mold.

(9) According to a second aspect of the present disclosure, there is provided an injection molding system. This injection molding system includes the plasticizing device and a mold clamping device in which a molding mold into which the plasticized material injected from the nozzle is placed.

(10) In the above embodiment, the system may further include an inspection device that inspects the quality of a molded product formed by injecting the plasticized material into the mold, and a memory unit that stores the inspection results of the molded product by the inspection device and a value related to the viscosity of the material used to mold the molded product, in association with each other. This embodiment makes it possible to accumulate data indicating the relationship between the quality of the molded product and the value related to the viscosity of the material used to mold the molded product.

(11) According to a third aspect of the present disclosure, there is provided a three-dimensional modeling system. This three-dimensional modeling system includes the plasticizing device and a modeling stage having a modeling surface on which the plasticized material ejected from the nozzle is deposited.

10...Plasticization device, 20...Mold clamping device, 21...Molding mold, 22...Fixed mold, 23...Movable mold, 24...Fixed section, 25...Mold drive section, 26...Ball screw, 30...Inspection device, 100...Injection molding system, 110...Material storage section, 120...Viscosity measurement section, 121...Moisture content measurement section, 122...Moisture content sensor, 126...Temperature measurement section, 127...Temperature sensor, 130...Storage time meter measuring section, 140...supply adjustment section, 150...plasticizing section, 160...nozzle, 170...gas detection section, 180...control section, 181...CPU, 182...determination section, 186...storage section, 210...guide case, 211...material inlet, 212...material outlet, 220...connection path, 230...material cutting plate, 231...cutting hole, 240...air cylinder, 250...piston rod, 251...finish Cutting plate, 260...first air pressure port, 270...second air pressure port, 310...flat screw, 311...screw case, 312...drive shaft, 313...drive motor, 314...material inlet, 315...groove forming surface, 316...center, 317...groove, 318...ridge portion, 320...barrel, 321...barrel case, 322...communicating hole, 323...flow path, 324...check valve, 325...opposing surface, 326...guide groove, 330...heating unit, 340...suction delivery unit, 341...suction delivery cylinder, 342...plunger, 343...plunger drive unit, 400...3D modeling system, 410...modeling stage, 411...modeling surface, 420...movement mechanism, 430...valve, 510...display unit, 520...alarm unit, RX...flat screw rotation axis

Claims (11)

a material storage unit that stores pellet-shaped material;
a plasticizing unit that plasticizes at least a portion of the material supplied from the material reservoir unit to generate a plasticized material;
a nozzle for injecting the plasticized material to the outside;
a viscosity measuring unit that measures values related to the viscosity of the material present at different positions in the material storage unit without contacting the material, and obtains a representative value related to the viscosity of the material in the material storage unit;
Plasticizing equipment. 2. The plasticizing device according to claim 1,
the viscosity measuring unit optically measures values related to the viscosity of the material present at different positions in the material reservoir;
Plasticizing equipment. 2. The plasticizing device according to claim 1,
a storage time measuring unit that measures the time the material is stored in the material storage unit;
Plasticizing equipment. 2. The plasticizing device according to claim 1,
a gas detection unit for detecting a gas generated when the material is plasticized;
Plasticizing equipment. 2. The plasticizing device according to claim 1,
a supply adjusting unit that adjusts the amount of the material supplied from the material storage unit to the plasticizing unit;
a control unit,
The plasticizing section comprises:
a rotating flat screw having a groove forming surface on which grooves are formed;
a barrel having an opposing surface facing the groove forming surface, the opposing surface having a communication hole communicating with the nozzle;
a heating section that heats the material supplied between the flat screw and the barrel,
The control unit
When the rotation speed of the flat screw is slowed down, the supply adjusting unit is controlled to reduce the amount of the material supplied from the material storage unit to the plasticizing unit per unit time.
Plasticizing equipment. 2. The plasticizing device according to claim 1,
a determination unit that determines whether a value related to the viscosity of the material measured by the viscosity measurement unit is below a predetermined threshold value;
Plasticizing equipment. 7. The plasticizing device according to claim 6,
A control unit is provided,
The plasticizing section comprises:
a rotating flat screw having a groove forming surface on which grooves are formed;
a barrel having an opposing surface facing the groove forming surface, the opposing surface having a communication hole communicating with the nozzle;
a heating section that heats the material supplied between the flat screw and the barrel,
The control unit
If the determination unit determines that the value related to the viscosity of the material is lower than the predetermined threshold value,
increasing the rotation speed of the flat screw or increasing the temperature of the barrel compared to when the value related to the viscosity of the material is equal to or greater than the predetermined threshold value;
Plasticizing equipment. 7. The plasticizing device according to claim 6,
a flow path through which the plasticized material flows;
a suction delivery cylinder connected to the flow path;
a plunger movably disposed within the suction-delivery cylinder for sucking the plasticized material into the suction-delivery cylinder or for delivering the plasticized material sucked into the suction-delivery cylinder toward the nozzle;
a control unit,
The control unit
If the determination unit determines that the value related to the viscosity of the material is lower than the predetermined threshold value,
increasing the injection speed of the plunger compared to when the value related to the viscosity of the material is equal to or greater than the predetermined threshold value;
Plasticizing equipment. A plasticizing device according to any one of claims 1 to 8;
a mold clamping device in which a molding die into which the plasticized material injected from the nozzle is injected is disposed.
Injection molding system. 10. The injection molding system of claim 9,
an inspection device that inspects the quality of a molded product formed by injecting the plasticized material into the mold;
a storage unit that stores the inspection result of the molded product by the inspection device and the value related to the viscosity of the material used to mold the molded product in association with each other,
Injection molding system. A plasticizing device according to any one of claims 1 to 8;
a building stage having a building surface on which the plasticized material ejected from the nozzle is deposited;
Three-dimensional modeling system.