Injection molding apparatus and injection molding method

Abstract

The invention relates to an injection molding device and an injection molding method, and provides a technology capable of improving the fluidity of a plasticized material during injection. The injection molding device performs injection molding of a molded article by injecting a plasticized material into a mold, and is provided with: a plasticizing unit for plasticizing a material to generate the plasticized material; the first flow path is communicated with the plasticizing part, and the plasticizing material flows through the first flow path; a first hot runner having a first nozzle portion that communicates with the first flow path and injects the plasticized material, and a first heater that heats the plasticized material in the first flow path; and a control unit for controlling injection of the plasticized material, the first nozzle unit comprising a metal material, the control unit comprising: a first temperature control unit electrically connected to the first heater and for controlling the temperature of the first heater; and a second temperature control unit that is electrically connected to the first nozzle unit and that controls the temperature of the first nozzle unit by supplying a current to the first nozzle unit.

Description

Technical Field

[0001] This disclosure relates to injection molding apparatus and injection molding method. Background Technology

[0002] Patent Document 1 discloses an injection molding apparatus having a hot runner. The hot runner has: a first heater disposed around a nozzle portion; and a second heater disposed at a position further away from the nozzle portion than the first heater.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2020-11488

[0004] When miniaturizing the hot runner, it becomes difficult to place heaters around small components such as the nozzle. Without heaters around the nozzle, it is impossible to heat the nozzle sufficiently, resulting in a decrease in the flowability of the plasticized material during injection. Summary of the Invention

[0005] According to a first aspect of this disclosure, an injection molding apparatus is provided. This injection molding apparatus injects a plasticizing material into a mold to perform injection molding of a molded article. The injection molding apparatus comprises: a plasticizing section for plasticizing materials to generate plasticizing material; a first flow path communicating with the plasticizing section for supplying the plasticizing material; a first hot runner having a first nozzle and a first heater, the first nozzle communicating with the first flow path and injecting the plasticizing material, the first heater heating the plasticizing material within the first flow path; and a control section for controlling the injection of the plasticizing material. The first nozzle is made of a metallic material, and the control section comprises: a first temperature control section electrically connected to the first heater and controlling the temperature of the first heater; and a second temperature control section electrically connected to the first nozzle and controlling the temperature of the first nozzle by supplying current to the first nozzle.

[0006] According to a second aspect of this disclosure, an injection molding method is provided. This injection molding method uses an injection molding apparatus to injection mold an article, the apparatus comprising: a plasticizing section for plasticizing material to generate a plasticized material; a first flow path communicating with the plasticizing section for supplying the plasticized material; and a first hot runner having a first nozzle and a first heater, the first nozzle communicating with the first flow path and injecting the plasticized material, the first heater heating the plasticized material within the first flow path, the first nozzle being made of a metallic material. The injection molding method comprises: a first step of controlling the temperature of the first heater; and a second step of controlling the temperature of the first nozzle by supplying an electric current to the first nozzle. Attached Figure Description

[0007] Figure 1 This is an explanatory diagram showing the general structure of an injection molding apparatus.

[0008] Figure 2 This is a cross-sectional view showing the general structure of the injection unit and the mold closing unit.

[0009] Figure 3 This is a three-dimensional diagram showing the general structure of a flat screw.

[0010] Figure 4 This is a rough top view of the bucket.

[0011] Figure 5 It is shown in magnification Figure 2 An explanatory diagram of the AR range.

[0012] Figure 6 This is an explanatory diagram showing the general structure of the first control unit.

[0013] Figure 7 This is a flowchart of the temperature control process.

[0014] Figure 8 This is a timing diagram illustrating the temperature control of the injection nozzle section by the second temperature control unit.

[0015] Figure 9 This is a timing diagram illustrating the temperature control of the injection nozzle section by the second temperature control unit in the second embodiment.

[0016] Figure 10 This is an explanatory diagram showing the schematic configuration of the injection molding apparatus in the third embodiment.

[0017] Figure 11 This is an explanatory diagram showing the general structure of the hot runner control unit and the first control unit.

[0018] Figure 12 This is an explanatory diagram showing the schematic configuration of the injection molding apparatus in the third embodiment.

[0019] Figure 13 This is a flowchart of the temperature control process in the third embodiment.

[0020] Figure 14 This is a timing diagram illustrating the temperature control of the first nozzle section and the second nozzle section by the second temperature control unit in the third embodiment.

[0021] Explanation of reference numerals in the attached figures

[0022] 10, 10c: Injection molding apparatus; 11: Base; 20: Injection unit; 21: Plasticizing section; 22: Suction and delivery section; 23: Injection section; 30: Mold closing unit; 40: First control section; 50: Hopper; 90, 90c: Molding mold; 91, 91c: Fixed mold; 92, 92c: Movable mold; 93: Hot runner mounting hole; 93c: First hot runner mounting hole; 93d: Second hot runner mounting hole; 94: End; 95: Gate opening; 99: Cavity; 110: Flat screw; 111: Screw housing; 112: Drive motor; 121: Groove forming surface; 122: Central section; 123: Groove; 124: Material feeding port; 125: Raised section; 130: Barrel; 131: Connecting hole; 132: Check valve; 133: Opposing surface; 134: Guide groove; 140: Barrel heater; 151: Injection cylinder; 152: Piston; 153: Piston drive section; 171: Molding mold drive unit; 172: Ball screw; 210: Main body; 220: Injection nozzle; 221: Connecting part; 222: Flange; 223: Front end; 224: Nozzle orifice; 225: Flow path inside the nozzle; 230: Injection heater; 240: Heat insulation part; 250: Temperature detection part; 260: Wiring part; 270: Flow path inside the injection part; 300: Hot runner unit; 310: Manifold; 320: Manifold Heater; 330: Manifold temperature detection unit; 340: First injection unit; 350: Second injection unit; 410: Processing unit; 411: Injection control unit; 412: First temperature control unit; 413: Second temperature control unit; 420: Storage unit; 430: Communication unit; 440: Input device; 450: Display device; 500: Hot runner control unit; 510: Processing unit; 520: Storage unit; 530: Communication unit; AX: Axis. Detailed Implementation

[0023] A. First implementation method:

[0024] Figure 1 This is an explanatory diagram showing the schematic configuration of the injection molding apparatus 10. Figure 1 The image shows arrows indicating the X, Y, and Z directions, which are orthogonal to each other. The X and Y directions are parallel to the horizontal plane. The Z direction is parallel to the vertical direction. Figure 1 The X, Y, and Z directions in this diagram indicate the same direction as those in other diagrams. When the orientation is determined, the direction indicated by the arrow (positive) is marked as "+", and the direction opposite to the arrow (negative) is marked as "-". Positive and negative labels are used in the directional descriptions.

[0025] The injection molding apparatus 10 includes an injection unit 20, a mold clamping unit 30, and a first control unit 40. The injection molding apparatus 10 uses a molding die 90 mounted on the mold clamping unit 30 to perform injection molding of a molded article. In this embodiment, a metal molding die 90 is mounted on the mold clamping unit 30. The molding die 90 mounted on the mold clamping unit 30 is not limited to metal; it can also be made of resin or ceramic. The metal molding die 90 is referred to as a metal mold. Alternatively, the molding die 90 is simply referred to as a die. The injection unit 20 and the mold clamping unit 30 are fixed to a base 11. The first control unit 40 is housed in the base 11.

[0026] The injection unit 20 is connected to a hopper 50 for dispensing material for the molded article. The material used for the molded article is, for example, a thermoplastic resin in granular form. Examples of thermoplastic resins used include ABS (acrylonitrile butadiene styrene), PC (polycarbonate), POM (polyacetal), PP (polypropylene), and PBT (polybutylene terephthalate). In addition to thermoplastic resins, the material for the molded article may also include metals and ceramics. Material supply to the injection unit 20 is not limited to the hopper 50; it can also be supplied via a material delivery tube.

[0027] The injection unit 20 plasticizes at least a portion of the material supplied from the hopper 50 to generate a plasticized material, and injects the generated plasticized material into the molding die 90. In this specification, "plasticization" refers to a process that includes melting, a change from a solid to a fluid state. Specifically, in the case of a material that undergoes a glass transition, plasticization means raising the material's temperature above the glass transition point. In the case of a material that does not undergo a glass transition, plasticization means raising the material's temperature above its melting point.

[0028] Figure 2 This is a cross-sectional view showing the general configuration of the injection unit 20 and the mold clamping unit 30. The injection unit 20 includes a plasticizing section 21, a suction and delivery section 22, and an injection section 23.

[0029] Plasticizing section 21 plasticizes at least a portion of the material supplied from hopper 50 to generate plasticized material. Plasticizing section 21 includes a flat screw 110, a barrel 130, and a barrel heater 140.

[0030] A flat screw 110 is housed in a screw housing 111. The flat screw 110 is also referred to as a rotor or simply a screw. The flat screw 110 is configured such that its axis coincides with the axis AX of the flow path within the injection section, as described later. The direction along axis AX is the X direction. The flat screw 110 is driven to rotate within the screw housing 111 by a drive motor 112 about axis AX. A connecting hole 131 is formed at the center of the barrel 130, extending through the barrel 130 along the X direction. The connecting hole 131 forms part of the flow path for the flow of plasticizing material. The axis of the connecting hole 131 coincides with axis AX. An injection cylinder 151, as described later, is connected to the connecting hole 131. A check valve 132 is provided upstream of the injection cylinder 151 in the connecting hole 131. A barrel heater 140 is embedded in the barrel 130. The rotation of the flat screw 110 based on the drive motor 112 and the heating based on the barrel heater 140 are controlled by a first control unit 40.

[0031] Figure 3 This is a perspective view showing the schematic configuration of the flat screw 110. The flat screw 110 has a generally cylindrical shape, with its height less than its diameter along its central axis. A vortex-shaped groove 123 is formed on the groove-forming surface 121 of the flat screw 110 opposite the barrel 130, centered on the central portion 122. The groove 123 communicates with a material inlet 124 formed on the side of the flat screw 110. Material supplied from the hopper 50 is supplied to the groove 123 through the material inlet 124. The groove 123 is formed by being separated by a protruding portion 125. Figure 3 Although an example with three grooves 123 is shown, the number of grooves 123 can be one or more. It should be noted that the grooves 123 are not limited to a spiral shape, but can also be a spiral or an involute curve, or can be a shape that extends in an arc from the central part 122 toward the outer periphery.

[0032] Figure 4 This is a schematic top view of the barrel 130. The barrel 130 has a facing surface 133 opposite to the groove forming surface 121 of the flat screw 110. A connecting hole 131 is formed in the center of the facing surface 133. A plurality of guide grooves 134 are formed on the facing surface 133, connecting to the connecting hole 131 and extending outward in a vortex shape from the connecting hole 131 toward the outer periphery. The material supplied to the groove 123 of the flat screw 110 is plasticized between the flat screw 110 and the barrel 130 by the rotation of the flat screw 110 and the heating of the barrel heater 140, and flows along the groove 123 and the guide grooves 134 by the rotation of the flat screw 110, and is guided toward the central portion 122 of the flat screw 110. The material flowing into the central portion 122 flows out from the connecting hole 131 provided in the center of the barrel 130 to the suction delivery portion 22. It should be noted that the guide grooves 134 may not be provided on the barrel 130. Alternatively, the guide groove 134 may not be connected to the connecting hole 131.

[0033] like Figure 2 As shown, the suction delivery unit 22 includes an injection cylinder 151, a piston 152, and a piston drive unit 153. Under the control of the first control unit 40, the suction delivery unit 22 controls the injection volume, injection speed, and injection pressure of the plasticizing material from the injection unit 23. The injection cylinder 151 is a generally cylindrical component connected to the communication hole 131 of the barrel 130, and has a piston 152 inside. The piston 152 slides inside the injection cylinder 151, pressing the plasticizing material inside the injection cylinder 151 into the injection unit 23. The piston 152 is driven by the piston drive unit 153, which is composed of an electric motor.

[0034] The injection section 23 injects the plasticized material pumped from the suction delivery section 22 into the molding die 90. The injection section 23 is configured as an open-gate hot runner, which guides the plasticized material into the molding die 90 in a heated state. In this embodiment, the injection section 23 is also referred to as the first hot runner.

[0035] The molding die 90 consists of a fixed die 91 and a movable die 92. The movable die 92 is mounted on the mold closing unit 30 opposite to the fixed die 91. The fixed die 91 is the die whose position is fixed during the mold closing operation. The movable die 92 is the die that moves relative to the fixed die 91 during the mold closing operation. The movable die 92 moves relative to the fixed die 91 along the mold closing direction via the mold closing unit 30. In this embodiment, the mold closing direction is the -X direction.

[0036] The mold closing unit 30 includes a molding die drive unit 171 and has the function of opening and closing the movable die 92 and the fixed die 91. Under the control of the first control unit 40, the mold closing unit 30 drives the molding die drive unit 171, which is composed of a motor, to rotate the ball screw 172, and moves the movable die 92, which is coupled to the ball screw 172, relative to the fixed die 91, thereby opening and closing the molding die 90. When the molding die 90 is closed, the fixed die 91 and the movable die 92 abut against each other, and a cavity with a predetermined molded product shape is formed between the fixed die 91 and the movable die 92.

[0037] Figure 5 It is shown in magnification Figure 2The diagram illustrates the range AR. A hot runner mounting hole 93 extending through the fixed mold 91 along the X direction is formed on the fixed mold 91. An injection section 23 is disposed in the hot runner mounting hole 93. The hot runner mounting hole 93 is formed by progressively narrowing its inner diameter from the plasticizing section 21 side. In this embodiment, the plasticizing section 21 side is the -X direction side. The end 94 of the hot runner mounting hole 93 on the side opposite to the plasticizing section 21 side is formed into a generally conical shape with a gradually narrowing inner diameter. The front end of the end 94 functions as a gate opening 95 for the plasticizing material to flow in. The gate opening 95 is configured as a generally circular hole. As described later, the gate opening 95 is configured as an open gate structure of a so-called annular gate. In this embodiment, the gate opening 95 is formed by direct connection to the cavity 99 of the molding mold 90.

[0038] The injection unit 23 includes a main body 210, an injection nozzle 220, an injection heater 230, a heat insulation part 240, a temperature detection part 250, and a wiring part 260. In this embodiment, the injection nozzle 220 is also referred to as the first nozzle part, and the injection heater 230 is also referred to as the first heater.

[0039] The main body 210 has a generally cylindrical external shape. In the main body 210, an internal thread (not shown) is formed on the inner circumferential surface of the end on the side of the gate opening 95.

[0040] An injection section internal flow path 270 is formed inside the main body 210 along the axis AX. The injection section internal flow path 270 communicates with the connecting hole 131. That is, the injection section internal flow path 270 communicates with the plasticizing section 21. The plasticizing material extruded from the suction delivery section 22 flows in the injection section internal flow path 270. In this embodiment, the injection section internal flow path 270 is also referred to as the first flow path.

[0041] The injection nozzle portion 220 communicates with the flow path 270 inside the injection section and injects plasticizing material. The injection nozzle portion 220 is fixedly disposed at the end of the injection section 23 on the side of the gate opening 95. The injection nozzle portion 220 has a connecting portion 221, a flange portion 222, and a front end portion 223. The connecting portion 221 is located in the injection nozzle portion 220 on the side of the plasticizing section 21 and has a generally cylindrical external shape. An external thread (not shown) is formed on the outer peripheral surface of the connecting portion 221. The injection nozzle portion 220 is fixed to the main body 210 by engaging the external thread with the internal thread formed on the main body portion 210. The flange portion 222 has an outer diameter larger than the outer diameter of the connecting portion 221 and is connected to the connecting portion 221. The end face of the flange portion 222 on the side of the plasticizing section 21 abuts against the end face of the main body portion 210 on the side of the gate opening 95. The front end 223 is connected to the flange 222 and has a generally conical appearance that protrudes toward the gate opening 95.

[0042] An internal flow path 225, communicating with the internal flow path 270 of the injection section and extending along the axis AX, is formed inside the injection nozzle section 220. In this embodiment, the connecting hole 131, the internal flow path 270 of the injection section, and the internal flow path 225 of the nozzle section are collectively referred to as the flow path. The internal flow path 225 of the nozzle section has the function of guiding the plasticized material to the gate opening 95. The internal flow path 225 of the nozzle section branches at the nozzle orifice 224 formed at the front end portion 223 of the injection nozzle section 220. The nozzle orifice 224 is opposite to the end portion 94 of the hot runner mounting hole 93. In this embodiment, two nozzle orifices 224 are formed at equal intervals in the circumferential direction at the front end portion 223, but it is not limited to two; four or any other number of nozzle orifices 224 may be formed. With this structure, when viewed along the axis AX, the internal flow path 225 of the nozzle section forms an annular shape centered on the front end portion 223 between the front end portion 223 and the end portion 94. Therefore, the gate opening 95 is composed of an open gate structure also known as a ring gate.

[0043] The main body 210 is made of aluminum. The injection nozzle 220 is made of SUS303. It should be noted that the main body 210 and the injection nozzle 220 are preferably made of materials with high thermal conductivity. The main body 210 may also be made of a metal material other than aluminum. The injection nozzle 220 may also be made of stainless steel other than SUS303, or of a metal material other than stainless steel such as aluminum.

[0044] The injection heater 230 heats the plasticized material within the flow path 270 of the injection section. The injection heater 230 is composed of a coil heater embedded in the main body 210. The injection heater 230 is arranged around the main body 210 in a manner that surrounds the main body 210. The temperature of the injection heater 230 is controlled by a first temperature control unit described later. Through this heating, the plasticized material flowing in the flow path 270 of the injection section is maintained in a molten state. It should be noted that the injection heater 230 is not limited to being a coil heater, but can also be any heater such as one with a heating element.

[0045] The heat insulation portion 240 is located in the gap between the main body portion 210 and the injection nozzle portion 220 and the hot runner mounting hole 93, in a gap closer to the plasticizing portion than the end portion 94. The heat insulation portion 240 suppresses heat transfer from the injection portion 23 to the fixed mold 91. In this embodiment, the heat insulation portion 240 is formed of the same resin material as the plasticizing material, but it can also be formed of any material with relatively low thermal conductivity, or it can be achieved through space.

[0046] A temperature sensing unit 250 is embedded in the main body 210. The temperature sensing unit 250 detects the temperature of the injection heater 230. The temperature sensing unit 250 is, for example, a thermocouple.

[0047] Wiring section 260 is connected to the side of main body section 210, which is located closer to plasticizing section 21 than injection heater 230. Wiring section 260 is a cylindrical component. Wiring used for controlling injection heater 230, wiring used for controlling temperature detection section 250, and wiring for supplying current to injection nozzle section 220 are housed inside wiring section 260.

[0048] Figure 6 This is an explanatory diagram showing the schematic configuration of the first control unit 40. The first control unit 40 is configured as a computer including a processing unit 410, a storage unit 420, and a communication unit 430. The processing unit 410 includes one or more processors. The processing unit 410 controls the operation of each part of the injection molding apparatus 10 by executing programs stored in the storage unit 420. The storage unit 420 is configured as a main storage device such as RAM and an auxiliary storage device such as a hard disk drive. It should be noted that the first control unit 40 may also be implemented by combining multiple circuits for implementing at least some of the functions, instead of being configured as a computer. An input device 440 such as a keyboard and mouse and a display device 450 such as a liquid crystal display are connected to the first control unit 40. It should be noted that the input device 440 and the display device 450 may also be integrated into a touch panel. In this embodiment, the first control unit 40 is also referred to as a control unit.

[0049] The processing unit 410 includes an injection control unit 411, a first temperature control unit 412, and a second temperature control unit 413. The injection control unit 411, the first temperature control unit 412, and the second temperature control unit 413 are implemented by the processing unit 410 executing a program stored in the storage unit 420. It should be noted that they can also be implemented by circuitry.

[0050] The injection control unit 411 controls the injection molding of the molded product by controlling various parts of the injection molding device 10, such as the drive motor 112, the barrel heater 140, the piston drive unit 153, and the molding die drive unit 171.

[0051] The first temperature control unit 412 is electrically connected to the injection heater 230 and controls the temperature of the injection heater 230. The first temperature control unit 412 controls the temperature of the injection heater 230 based on the set temperature of the injection heater 230 and the temperature detected by the temperature detection unit 250, so that the temperature of the injection heater 230 becomes the set temperature.

[0052] The second temperature control unit 413 is electrically connected to the injection nozzle section 220 and controls the temperature of the injection nozzle section 220 by supplying current to it. In this embodiment, a frame (not shown) connected to the injection nozzle section 220 via other components and housing the injection unit 20 is grounded. Therefore, by supplying current to the injection nozzle section 220, current flows within it, causing the injection nozzle section 220 to heat up. In this embodiment, the second temperature control unit 413 is electrically connected to the injection nozzle section 220 via the main body section 210. It should be noted that the second temperature control unit 413 may also be electrically connected to the injection nozzle section 220 directly without going through the main body section 210.

[0053] The second temperature control unit 413 controls the current supplied to the injection nozzle section 220 by executing PWM (Pulse Width Modulation) control. The second temperature control unit 413 controls the temperature of the injection nozzle section 220 by controlling the duty cycle in the PWM control. Specifically, the second temperature control unit 413 increases the temperature of the injection nozzle section 220 by increasing the duty cycle and decreases the temperature of the injection nozzle section 220 by decreasing the duty cycle. It should be noted that the second temperature control unit 413 can also control the current supplied to the injection nozzle section 220 by executing control methods other than PWM control.

[0054] The second temperature control unit 413 controls the temperature of the injection nozzle section 220 by executing multiple controls, including a first control and a second control. Here, the first control refers to supplying current to the injection nozzle section 220 to make its temperature reach a first temperature. The second control refers to supplying current to the injection nozzle section 220 to make its temperature reach a second temperature higher than the first temperature. In this embodiment, the second temperature control unit 413 makes the duty cycle in the second control higher than the duty cycle in the first control, thereby making the temperature of the injection nozzle section 220 in the second control higher than the temperature in the first control. In this specification, the state in which the first control is performed is referred to as the preheating state, and the state in which the second control is performed is referred to as the heating state.

[0055] Figure 7 This is a flowchart of the temperature control process. The temperature control process is performed during injection molding of the molded product in the injection molding apparatus 10. Figure 8 This is a timing diagram illustrating the temperature control of the injection nozzle section 220 by the second temperature control unit 413 in the temperature control process.

[0056] In step S10, the plasticizing section 21 plasticizes the material to generate a plasticized material.

[0057] In step S20, the first temperature control unit 412 controls the temperature of the injection heater 230. Specifically, the first temperature control unit 412 controls the temperature of the injection heater 230 so that the temperature of the plasticizing material in the flow path 270 of the injection section exceeds the plasticizing temperature. Step S20 is also referred to as the first process.

[0058] In step S30, the second temperature control unit 413 controls the temperature of the injection nozzle section 220. First, the second temperature control unit 413 executes first control upon receiving a timing signal from the injection control unit 411. Here, the timing signal refers to the signal sent from the injection control unit 411 when the mold 90 begins to close. Figure 8 In the timing diagram shown, the second temperature control unit 413 receives a timing signal at time T1 and performs first control. The second temperature control unit 413, for example, sets the duty cycle to 10% and supplies current to the injection nozzle 220. The second temperature control unit 413 counts the elapsed time from the time the timing signal is received. If the elapsed time exceeds a predetermined time, i.e., a first time, the second temperature control unit 413 performs second control. Here, the first time is the time from the start of mold closing to the time when the piston 152 begins to move to press the plasticized material in the injection cylinder 151 into the injection unit 23. The first time is pre-stored in the storage unit 420. The first time is, for example, about 3 to 5 seconds. That is, the second temperature control unit 413 performs first control before injecting plasticized material from the injection nozzle 220. Figure 8 In the timing diagram shown, at time T2, the first time has elapsed since the time signal was received.

[0059] The second temperature control unit 413 performs second control at time T2. The second temperature control unit 413, for example, sets the duty cycle to 75% and supplies current to the injection nozzle 220. Preferably, the second temperature control unit 413 supplies current to the injection nozzle 220 so that the temperature of the injection nozzle 220 is the same as the temperature of the injection heater 230. The second temperature control unit 413 counts the elapsed time from the start of the second control. If the elapsed time exceeds a predetermined time, i.e., a second time, the second temperature control unit 413 performs first control. Here, the second time is the time from the point when the piston 152 begins to move to press the plasticizing material in the injection cylinder 151 into the injection section 23 to the point when the injection of plasticizing material from the injection nozzle 220 is completed. The second time is pre-stored in the storage unit 420. The second time is, for example, about 0.1 seconds to 1 second. That is, the second temperature control unit 413 performs second control when plasticizing material is injected from the injection nozzle 220. Figure 8In the timing diagram shown, at time T3, the second time has passed since the start of the second control.

[0060] The second temperature control unit 413 performs the first control at time T3. For example, the second temperature control unit 413 supplies current to the injection nozzle 220 with a duty cycle of 10%. That is, the second temperature control unit 413 performs the first control after the plasticizing material is injected from the injection nozzle 220. As described above, in step S30, the plasticizing material is injected into the molding die 90. Step S30 is also referred to as the second process.

[0061] In step S40, the injection control unit 411 controls the mold closing unit 30 to open the molding die 90. The molded product is then ejected by the ejector pin and removed from the molding die 90.

[0062] In step S50, the second temperature control unit 413 determines whether a stop signal has been received from the injection control unit 411. If a stop signal is received, step S60 is executed. If no stop signal is received, the process returns to step S30. The stop signal is sent from the injection control unit 411, for example, when the entire injection molding cycle is completed.

[0063] If the process returns to step S30, injection molding of the molded article is performed again. Figure 8 The diagram shows the process returning to step S30, where the second temperature control unit 413 receives a timing signal at time T4. Figure 8 In the example shown, the second temperature control unit 413 performs first control from time T4 to time T5, performs second control from time T5 to time T6, and performs first control from time T6 to time T7.

[0064] In step S60, the second temperature control unit 413 stops supplying current to the injection nozzle unit 220. Specifically, the second temperature control unit 413 sets the duty cycle to 0%. Figure 8 In the timing diagram shown, the second temperature control unit 413 stops supplying current to the injection nozzle unit 220 at time T7. Furthermore, the injection control unit 411 controls each part of the injection molding apparatus 10 to stop the injection molding of the molded article. Temperature control processing is performed as explained above.

[0065] According to the first embodiment described above, the injection molding apparatus 10 includes an injection section 23 having an injection nozzle section 220 made of a metal material. A second temperature control section 413 is electrically connected to the injection nozzle section 220 and controls the temperature of the injection nozzle section 220 by supplying current to it. In other words, the injection molding apparatus 10 includes a first hot runner having a first nozzle section made of a metal material, and the second temperature control section 413 is electrically connected to the first nozzle section, controlling its temperature by supplying current to it. Therefore, the first nozzle section can be heated even without a heater around it. Consequently, the flowability of the plasticized material during injection can be improved.

[0066] Furthermore, in this embodiment, the second temperature control unit 413 controls the temperature of the injection nozzle section 220 by executing multiple controls, including a first control and a second control. The first control supplies current to the injection nozzle section 220 to make its temperature reach a first temperature, and the second control supplies current to the injection nozzle section 220 to make its temperature reach a second temperature higher than the first temperature. In other words, the second temperature control unit 413 controls the temperature of the first nozzle section by executing multiple controls, including a first control and a second control. The first control supplies current to the first nozzle section to make its temperature reach the first temperature, and the second control supplies current to the first nozzle section to make its temperature reach a second temperature higher than the first temperature. Therefore, the temperature of the first nozzle section can be controlled according to the plasticizing temperature of the material. As a result, even if the material used in injection molding is changed, the flowability of the plasticized material during injection can be improved.

[0067] Furthermore, in this embodiment, the second temperature control unit 413 performs first control before injecting the plasticizing material from the injection nozzle 220, and performs second control when the plasticizing material is injected from the injection nozzle 220. In other words, the second temperature control unit 413 performs first control before injecting the plasticizing material from the first nozzle, and performs second control when the plasticizing material is injected from the first nozzle. Therefore, before injecting the plasticizing material, the temperature of the first nozzle is maintained at a temperature at which the plasticizing material can maintain its fluidity, and when the plasticizing material is injected, the temperature of the first nozzle can be further increased. Engineering plastics such as polyetheretherketone (PEEK) and polyimide will change their material properties if they are continuously heated at high temperatures. In this embodiment, when the above-mentioned engineering plastics are used in injection molding, changes in material properties can be suppressed.

[0068] Furthermore, in this embodiment, the second temperature control unit 413 performs the first control after the plasticizing material is injected from the injection nozzle 220. In other words, the second temperature control unit 413 performs the first control after the plasticizing material is injected from the first nozzle. Therefore, after the plasticizing material is injected, the temperature of the first nozzle can be maintained at the first temperature. Consequently, in the case of repeated injection molding, the heating time of the first nozzle can be shortened, and the injection molding cycle can be shortened.

[0069] B. Second implementation method:

[0070] In the second embodiment, the temperature control process differs from that in the first embodiment. The configuration of each part of the injection molding apparatus 10 in the second embodiment is the same as that in the first embodiment.

[0071] Figure 9 This is a timing diagram illustrating the temperature control of the injection nozzle section 220 by the second temperature control unit 413 in the second embodiment. In the second embodiment, in Figure 7 In step S30 of the temperature control process shown, the second temperature control unit 413 stops supplying current to the injection nozzle 220 after the plasticizing material is injected from the injection nozzle 220. Specifically, the second temperature control unit 413 stops supplying current to the injection nozzle 220 after a second time has elapsed since the start of the second control. Figure 9 In the example shown, the second temperature control unit 413 stops supplying current to the injection nozzle unit 220 at times T3 and T6. In the second embodiment, since the current supply to the injection nozzle unit 220 is stopped in step S30, the operation is not performed. Figure 7 Step S60.

[0072] According to the second embodiment described above, the second temperature control unit 413 stops supplying current to the injection nozzle 220 after the plasticizing material is injected from the injection nozzle 220. In other words, the second temperature control unit 413 stops supplying current to the first nozzle after the plasticizing material is injected from the first nozzle. Therefore, the temperature of the first nozzle drops after the plasticizing material is injected. As a result, the molded article can be easily cured.

[0073] C. Third implementation method:

[0074] Figure 10This is an explanatory diagram showing a schematic configuration of the injection molding apparatus 10c according to the third embodiment. The injection molding apparatus 10c also includes a hot runner unit 300 and a hot runner control unit 500. The hot runner control unit 500 is connected to the hot runner unit 300 and the first control unit 40 in a manner that enables communication via a communication line. In the third embodiment, the first control unit 40 and the hot runner control unit 500 are also collectively referred to as the control unit.

[0075] Figure 11 This is an explanatory diagram showing the schematic configuration of the hot runner control unit 500 and the first control unit 40. The hot runner control unit 500 includes a processing unit 510, a storage unit 520, and a communication unit 530. The processing unit 510 is composed of one or more processors. The storage unit 520 is composed of storage devices such as RAM and ROM. The communication unit 530 is an interface for communicating with the hot runner unit 300 and the first control unit 40.

[0076] The processing unit 510 includes a first temperature control unit 412 and a second temperature control unit 413. The first temperature control unit 412 and the second temperature control unit 413 are implemented by the processing unit 510 executing a program stored in the storage unit 520. It should be noted that they can also be implemented by circuitry. In the third embodiment, the processing unit 410 of the first control unit 40 includes an injection control unit 411, but does not include the first temperature control unit 412 and the second temperature control unit 413.

[0077] Figure 12 This is an explanatory diagram showing a schematic configuration of the injection molding apparatus 10c in the third embodiment. It should be noted that... Figure 12 The diagram of the mold-closing unit 30 is omitted. The configuration of each part of the injection unit 20 and the mold-closing unit 30 in the third embodiment is the same as that in the first embodiment.

[0078] Reference Figure 12 The structure of the hot runner unit 300 and the molding die 90c in the third embodiment will be described. The hot runner unit 300 is disposed between the injection section 23 and the fixed die 91c. The hot runner unit 300 includes a manifold 310, a manifold heater 320, a manifold temperature detection section 330, a first injection section 340, and a second injection section 350.

[0079] A manifold flow path (not shown) is formed within the manifold 310. The beginning of the manifold flow path is connected to the gate opening 95 of the injection section 23. The manifold flow path branches into two flow paths within the manifold 310. Each of the branched flow paths is connected to the first flow path (described later) of the first injection section 340 and the second flow path (described later) of the second injection section 350, respectively. The plasticized material within the manifold flow path is heated by a manifold heater 320 inserted into the manifold 310. Heating the manifold 310 by the manifold heater 320 maintains the molten state of the plasticized material within the manifold flow path. The temperature of the manifold heater 320 is controlled by a hot runner control section 500. A manifold temperature detection section 330 is inserted into the manifold 310 and detects the temperature of the manifold 310. The manifold temperature detection section 330 is, for example, a thermocouple.

[0080] In the third embodiment, two hot runner mounting holes 93 are formed on the fixed mold 91c, extending through the fixed mold 91c in the X direction. Hereinafter, one hot runner mounting hole 93 will be referred to as the first hot runner mounting hole 93c, and the other hot runner mounting hole 93 will be referred to as the second hot runner mounting hole 93d. A first injection portion 340 is disposed in the first hot runner mounting hole 93c, and a second injection portion 350 is disposed in the second hot runner mounting hole 93d.

[0081] The configurations of each part of the first injection section 340 and the second injection section 350 are the same as those of the injection section 23 of the injection unit 20. In the third embodiment, the first injection section 340 is also referred to as the first hot runner, and the second injection section 350 is also referred to as the second hot runner. Furthermore, in the third embodiment, the component of the first injection section 340 corresponding to the injection nozzle section 220 of the injection section 23 is also referred to as the first nozzle section, the component of the first injection section 340 corresponding to the injection heater 230 of the injection section 23 is also referred to as the first heater, and the component of the first injection section 340 corresponding to the injection section internal flow path 270 of the injection section 23 is also referred to as the first flow path. Additionally, in the third embodiment, the component of the second injection section 350 corresponding to the injection nozzle section 220 of the injection section 23 is also referred to as the second nozzle section, the component of the second injection section 350 corresponding to the injection heater 230 of the injection section 23 is also referred to as the second heater, and the component of the second injection section 350 corresponding to the injection section internal flow path 270 of the injection section 23 is also referred to as the second flow path. In the third embodiment, the connecting hole 131, the flow path 270 inside the injection section, the flow path 225 inside the nozzle section, the manifold flow path, the first flow path, and the second flow path are collectively referred to as flow paths. The first flow path and the second flow path are connected to the plasticizing section 21 to allow the plasticizing material injected from the injection section 23 to flow.

[0082] Two cavities 99 are formed between the fixed mold 91c and the movable mold 92c. The first injection section 340 and the second injection section 350 inject plasticizing material into the different cavities 99 respectively.

[0083] In the third embodiment, the injection control unit 411 controls the temperature of the injection heater 230 of the injection unit 23, and then supplies current to the injection nozzle 220 of the injection unit 23 to control the temperature of the injection nozzle 220. The injection control unit 411 controls the temperature of the injection heater 230 and the temperature of the injection nozzle 220 to maintain the molten state of the plasticized material in the flow path 270 of the injection unit and the flow path 225 of the nozzle.

[0084] The first temperature control unit 412 is electrically connected to the first heater and controls the temperature of the first heater. Based on a set temperature of the first heater and the temperature detected by a temperature detection unit in the first injection unit 340, the first temperature control unit 412 controls the temperature of the first heater to achieve the set temperature. Additionally, the first temperature control unit 412 is electrically connected to the second heater and controls the temperature of the second heater. Based on a set temperature of the second heater and the temperature detected by a temperature detection unit in the second injection unit 350, the first temperature control unit 412 controls the temperature of the second heater to achieve the set temperature.

[0085] The second temperature control unit 413 is electrically connected to the first nozzle section and controls the temperature of the first nozzle section by supplying current to it. Similarly, the second temperature control unit 413 is electrically connected to the second nozzle section and controls its temperature by supplying current to it. Specifically, the second temperature control unit 413 controls the current supplied to both the first and second nozzle sections by performing PWM control independently. Furthermore, the second temperature control unit 413 independently controls the temperatures of both the first and second nozzle sections by supplying current to them separately.

[0086] The second temperature control unit 413 controls the temperature of the first nozzle section by executing multiple controls, including a first control and a second control. In this embodiment, the first control refers to supplying current to the first nozzle section to make the temperature of the first nozzle section reach a first temperature. The second control refers to supplying current to the first nozzle section to make the temperature of the first nozzle section reach a second temperature higher than the first temperature. Furthermore, the second temperature control unit 413 controls the temperature of the second nozzle section by executing multiple controls, including a third control and a fourth control. The third control refers to supplying current to the second nozzle section to make the temperature of the second nozzle section reach a third temperature. The fourth control refers to supplying current to the second nozzle section to make the temperature of the second nozzle section reach a fourth temperature higher than the third temperature. The second temperature control unit 413 makes the duty cycle in the fourth control higher than the duty cycle in the third control, thereby making the temperature of the second nozzle section in the fourth control higher than the temperature of the second nozzle section in the third control. In this specification, the state in which the third control is performed is also referred to as the preheating state, and the state in which the fourth control is performed is also referred to as the heating state. In this embodiment, the third temperature is a temperature different from the first temperature, and the fourth temperature is a temperature different from the second temperature. That is, the second temperature control unit 413 controls the temperatures of the first nozzle section and the second nozzle section in a manner that the temperatures of the first nozzle section and the second nozzle section are different for each of them. It should be noted that the third temperature and the first temperature can also be the same. In addition, the fourth temperature and the second temperature can also be the same.

[0087] Figure 13 This is a flowchart of the temperature control process in the third embodiment. It should be noted that parts performing the same processes as the temperature control process in the first embodiment are labeled with the same reference numerals and their descriptions are omitted. Figure 14 This is a timing diagram illustrating the temperature control of the first nozzle section and the second nozzle section by the second temperature control unit 413 in the third embodiment.

[0088] In step S21, the first temperature control unit 412 controls the temperatures of the first heater and the second heater. Specifically, the first temperature control unit 412 controls the temperatures of the first heater and the second heater so that the temperature of the plasticizing material in the first flow path and the second flow path exceeds the plasticizing temperature.

[0089] In step S31, the second temperature control unit 413 controls the temperature of the first nozzle section and the second nozzle section. First, upon receiving a timing signal from the injection control unit 411, the second temperature control unit 413 executes first control and third control. The second temperature control unit 413 controls the temperature in a manner that differs from the start timing of the first control in the first nozzle section and the start timing of the third control in the second nozzle section. Figure 14In the timing diagram shown, the second temperature control unit 413 receives a timing signal at time T11. The second temperature control unit 413 starts third control at time T11. The second temperature control unit 413 starts first control at time T12, after a predetermined time has elapsed from time T11. The predetermined time is a value determined in advance in the storage unit 520 based on the temperature characteristics difference between the first injection unit 340 and the second injection unit 350, the difference in length between the gate opening 95 and the manifold flow path between each injection unit 23.

[0090] The second temperature control unit 413 executes second control and fourth control when a first time has elapsed since the time point from receiving the timing signal. The second temperature control unit 413 performs control in a manner different from the start timing of the second control in the first nozzle unit and the start timing of the fourth control in the second nozzle unit. Figure 14 In the timing diagram shown, at time T13, a first time has elapsed since the timing signal was received. The second temperature control unit 413 begins fourth control at time T13. The second temperature control unit 413 begins second control at time T14, after a predetermined time has elapsed since time T13. The predetermined time is a value determined in advance in the storage unit 520 based on the temperature difference between the first injection unit 340 and the second injection unit 350, the difference in length between the gate opening 95 and the manifold flow path between each injection unit 23.

[0091] The second temperature control unit 413 executes first control and third control when the time elapsed since the time the timing signal was received is equal to the time between the sum of the first and second times. Figure 14 In the timing diagram shown, at time T15, the time elapsed from the moment the timing signal is received to the time when the first and second times are added together. The second temperature control unit 413 begins the first control and the third control at time T15.

[0092] In step S61, the second temperature control unit 413 stops supplying current to the first nozzle unit and the second nozzle unit.

[0093] According to the third embodiment described above, the injection molding apparatus 10 includes: a first hot runner having a first nozzle portion made of a metal material; and a second hot runner having a second nozzle portion made of a metal material. A second temperature control unit 413 is electrically connected to the first and second nozzle portions, and controls the temperature of the first and second nozzle portions independently by supplying current to each nozzle portion separately. Therefore, the temperature of the first and second nozzle portions can be controlled based on the temperature difference between the first and second hot runners, the difference in flow path length from the plasticizing section 21 to each hot runner, etc.

[0094] Furthermore, in this embodiment, the second temperature control unit 413 controls the temperatures of the first nozzle section and the second nozzle section in a manner where the temperatures of the first nozzle section and the second nozzle section are different for each. Therefore, the temperatures of the first nozzle section and the second nozzle section can be controlled based on the difference in temperature characteristics between the first and second hot runners and the difference in flow path length from the plasticizing section 21 to each hot runner. For example, when the flow path length from the plasticizing section 21 to the first hot runner is longer than the flow path length from the plasticizing section 21 to the second hot runner, the temperature of the plasticized material in the first hot runner tends to become lower than the temperature of the plasticized material in the second hot runner. In this case, by making the temperature of the first nozzle section higher than the temperature of the second nozzle section, the temperatures of the plasticized material in the first and second hot runners can be made to be at the same level.

[0095] Furthermore, in this embodiment, the second temperature control unit 413 controls the temperature of the second nozzle section by executing multiple controls, including a third control and a fourth control. The control is performed in a manner where the start timing of the first control in the first nozzle section differs from the start timing of the third control in the second nozzle section, or the start timing of the second control in the first nozzle section differs from the start timing of the fourth control in the second nozzle section. The third control supplies current to the second nozzle section to make its temperature a third temperature, and the fourth control supplies current to the second nozzle section to make its temperature a fourth temperature higher than the third temperature. Therefore, the temperatures of the first and second nozzle sections can be controlled based on the temperature difference between the first and second hot runners and the difference in flow path length from the plasticizing section 21 to each hot runner.

[0096] D. Other implementation methods:

[0097] (D-1) In the above embodiment, the second temperature control unit 413 performs second control when a first time has elapsed since the time point from when the timing signal is received. Alternatively, the second temperature control unit 413 may continuously perform first control from the time point from when the timing signal is received until the time point from when the stop signal is received.

[0098] (D-2) In the above embodiment, the hot runner unit 300 has two hot runners: a first hot runner and a second hot runner. Alternatively, the hot runner unit 300 may have three or more hot runners.

[0099] (D-3) In the above embodiment, the second temperature control unit 413 controls the temperature of the first nozzle section by executing multiple controls, including the first control and the second control. Alternatively, the second temperature control unit 413 may not execute the first control and the second control.

[0100] (D-4) In the above embodiment, the second temperature control unit 413 performs first control before injecting plasticizing material from the first nozzle, and performs second control when plasticizing material is injected from the first nozzle. Alternatively, the second temperature control unit 413 may not perform the first control before injecting plasticizing material from the first nozzle. Furthermore, the second temperature control unit 413 may not perform the second control when plasticizing material is injected from the first nozzle.

[0101] (D-5) In the above embodiment, the second temperature control unit 413 performs the first control after the plasticizing material is injected from the first nozzle. Alternatively, the second temperature control unit 413 may not perform the first control after the plasticizing material is injected from the first nozzle.

[0102] (D-6) In the above embodiment, the second temperature control unit 413 controls the temperatures of the first nozzle section and the second nozzle section in such a way that the temperatures of the first nozzle section and the second nozzle section are different. Alternatively, the second temperature control unit 413 may control the temperatures of the first nozzle section and the second nozzle section in such a way that the temperatures of the first nozzle section and the second nozzle section become equal.

[0103] (D-7) In the above embodiment, the second temperature control unit 413 performs control in a manner where the start timing of the first control in the first nozzle unit and the start timing of the third control in the second nozzle unit are different from those of the second control in the first nozzle unit and the fourth control in the second nozzle unit. Alternatively, the second temperature control unit 413 may also perform control in a manner where at least one of the start timings of the first control in the first nozzle unit and the third control in the second nozzle unit, and the start timings of the second control in the first nozzle unit and the fourth control in the second nozzle unit are simultaneous.

[0104] (D-8) In the above embodiment, the second temperature control unit 413 controls the temperature of the second nozzle section by executing multiple controls, including a third control and a fourth control. Alternatively, the second temperature control unit 413 may not execute the third control and the fourth control.

[0105] (D-9) In the third embodiment, the second temperature control unit 413 performs control in such a way that the start timing of the first control in the first nozzle unit is later than the start timing of the third control in the second nozzle unit. Alternatively, the second temperature control unit 413 may also perform control in such a way that the start timing of the first control in the first nozzle unit is earlier than the start timing of the third control in the second nozzle unit.

[0106] (D-10) In the third embodiment, the second temperature control unit 413 performs control in such a way that the start timing of the second control in the first nozzle unit is later than the start timing of the fourth control in the second nozzle unit. Alternatively, the second temperature control unit 413 may also perform control in such a way that the start timing of the second control in the first nozzle unit is earlier than the start timing of the fourth control in the second nozzle unit.

[0107] E. Other methods:

[0108] This disclosure is not limited to the embodiments described above, and can be implemented in various ways without departing from its spirit. For example, this disclosure can also be implemented in the following ways. The technical features in the above embodiments corresponding to the technical features in the various methods described below can be appropriately replaced or combined to solve part or all of the technical problem to be solved by this disclosure, or to achieve part or all of the effects of this disclosure. In addition, if a technical feature is not required to be described in this specification, it can be appropriately deleted.

[0109] (1) According to a first aspect of the present disclosure, an injection molding apparatus is provided. The injection molding apparatus injects a plasticizing material into a mold to perform injection molding of a molded article. The injection molding apparatus comprises: a plasticizing section for plasticizing a material to generate a plasticizing material; a first flow path communicating with the plasticizing section for supplying the plasticizing material; a first hot runner having a first nozzle and a first heater, the first nozzle communicating with the first flow path and injecting the plasticizing material, the first heater heating the plasticizing material within the first flow path; and a control section for controlling the injection of the plasticizing material, the first nozzle being made of a metallic material, the control section comprising: a first temperature control section electrically connected to the first heater and controlling the temperature of the first heater; and a second temperature control section electrically connected to the first nozzle and controlling the temperature of the first nozzle by supplying current to the first nozzle.

[0110] In this way, the first nozzle section can be heated even when no heater is provided around it. Therefore, the flowability of the plasticized material during injection can be improved.

[0111] (2) In the above method, the second temperature control unit may control the temperature of the first nozzle by executing a plurality of controls including a first control and a second control. The first control is to supply current to the first nozzle so that the temperature of the first nozzle becomes a first temperature, and the second control is to supply current to the first nozzle so that the temperature of the first nozzle becomes a second temperature higher than the first temperature.

[0112] In this way, the temperature of the first nozzle can be controlled according to the plasticizing temperature of the material. Therefore, even if the material used in injection molding is changed, the flowability of the plasticized material during injection can be improved.

[0113] (3) In the above manner, the second temperature control unit may perform the first control before injecting the plasticizing material from the first nozzle, and the second temperature control unit may perform the second control when injecting the plasticizing material from the first nozzle.

[0114] In this way, before injecting the plasticizing material, the temperature of the first nozzle can be maintained at a temperature at which the plasticizing material can maintain its fluidity, and when injecting the plasticizing material, the temperature of the first nozzle can be further increased.

[0115] (4) In the above manner, the second temperature control unit may perform the first control after injecting the plasticizing material from the first nozzle.

[0116] In this manner, after the plasticizing material is injected, the temperature of the first nozzle can be maintained at a first temperature. Therefore, in the case of repeated injection molding, the heating time of the first nozzle can be shortened, and the injection molding cycle can be shortened.

[0117] (5) In the above manner, the second temperature control unit may stop supplying current to the first nozzle after injecting the plasticizing material from the first nozzle.

[0118] In this manner, the temperature of the first nozzle drops after the plasticizing material is injected. This allows the molded part to solidify more easily.

[0119] (6) In the above-described manner, the injection molding apparatus may also include: a second flow path connected to the plasticizing section for the flow of the plasticizing material; and a second hot runner having a second nozzle section and a second heater, the second nozzle section being connected to the second flow path for injecting the plasticizing material, the second heater heating the plasticizing material in the second flow path, the second nozzle section being made of a metal material, the first temperature control section being electrically connected to the second heater and controlling the temperature of the second heater, the second temperature control section being electrically connected to the second nozzle section and controlling the temperature of the second nozzle section by supplying current to the second nozzle section, the second temperature control section controlling the temperature of the first nozzle section and the second nozzle section separately by supplying current to the first nozzle section and the second nozzle section separately.

[0120] In this way, the temperature of the first nozzle section and the temperature of the second nozzle section can be controlled based on the temperature difference between the first hot runner and the second hot runner, and the difference in the flow path length from the plasticizing section to each hot runner.

[0121] (7) In the above manner, the second temperature control unit may control the temperature of the first nozzle section and the temperature of the second nozzle section in such a way that the temperature of the first nozzle section and the temperature of the second nozzle section are different from each other.

[0122] In this way, the temperature of the first nozzle section and the temperature of the second nozzle section can be controlled based on the temperature difference between the first hot runner and the second hot runner, and the difference in the flow path length from the plasticizing section to each hot runner.

[0123] (8) In the above-described manner, the second temperature control unit may control the temperature of the first nozzle section by executing multiple controls including a first control and a second control. The first control is to supply current to the first nozzle section to make the temperature of the first nozzle section a first temperature. The second control is to supply current to the first nozzle section to make the temperature of the first nozzle section a second temperature higher than the first temperature. The second temperature control unit controls the temperature of the second nozzle section by executing multiple controls including a third control and a fourth control. The third control is to supply current to the second nozzle section to make the temperature of the second nozzle section a third temperature. The fourth control is to supply current to the second nozzle section to make the temperature of the second nozzle section a fourth temperature higher than the third temperature. The second temperature control unit controls the temperature in a manner that the start timing of the first control in the first nozzle section and the start timing of the third control in the second nozzle section are different, or the start timing of the second control in the first nozzle section and the start timing of the fourth control in the second nozzle section are different.

[0124] In this way, the temperature of the first nozzle section and the temperature of the second nozzle section can be controlled based on the temperature difference between the first hot runner and the second hot runner, and the difference in the flow path length from the plasticizing section to each hot runner.

[0125] (9) According to a second aspect of this disclosure, an injection molding method is provided. This injection molding method involves injection molding an article using an injection molding apparatus, the injection molding apparatus comprising: a plasticizing section for plasticizing material to generate a plasticized material; a first flow path communicating with the plasticizing section for supplying the plasticized material; and a first hot runner having a first nozzle and a first heater, the first nozzle communicating with the first flow path and injecting the plasticized material, the first heater heating the plasticized material within the first flow path, the first nozzle being made of a metallic material, the injection molding method comprising: a first step of controlling the temperature of the first heater; and a second step of controlling the temperature of the first nozzle by supplying an electric current to the first nozzle.

[0126] In this way, the first nozzle section can be heated even when no heater is provided around it. Therefore, the flowability of the plasticized material during injection can be improved.

Claims

1. An injection molding apparatus, characterized in that, Injection molding involves injecting plasticizing materials into a mold to produce molded parts. The injection molding apparatus includes: The plasticizing department plasticizes materials to produce plasticized materials; The first flow path is connected to the plasticizing section, allowing the plasticizing material to flow; A first hot runner has a first nozzle and a first heater. The first nozzle is connected to the first flow path and injects the plasticizing material. The first heater heats the plasticizing material within the first flow path. The control unit controls the injection of the plasticizing material. The first nozzle section is made of metal. The control unit has: A first temperature control unit is electrically connected to the first heater and controls the temperature of the first heater. as well as The second temperature control unit is electrically connected to the first nozzle unit and controls the temperature of the first nozzle unit by supplying current to the first nozzle unit.

2. The injection molding apparatus according to claim 1, characterized in that, The second temperature control unit controls the temperature of the first nozzle section by executing multiple controls, including the first control and the second control. The first control is to supply current to the first nozzle section so that the temperature of the first nozzle section reaches a first temperature. The second control is to supply current to the first nozzle section so that the temperature of the first nozzle section becomes a second temperature higher than the first temperature.

3. The injection molding apparatus according to claim 2, characterized in that, The second temperature control unit performs the first control before injecting the plasticizing material from the first nozzle. The second temperature control unit performs the second control when the plasticizing material is injected from the first nozzle.

4. The injection molding apparatus according to claim 3, characterized in that, The second temperature control unit performs the first control after the plasticizing material is injected from the first nozzle.

5. The injection molding apparatus according to claim 3, characterized in that, After the plasticizing material is injected from the first nozzle, the second temperature control unit stops supplying current to the first nozzle.

6. The injection molding apparatus according to claim 1, characterized in that, The injection molding apparatus also includes: A second flow path, connected to the plasticizing section, is used for the flow of the plasticizing material; and The second hot runner has a second nozzle and a second heater. The second nozzle is connected to the second flow path and injects the plasticizing material. The second heater heats the plasticizing material in the second flow path. The second nozzle is made of metal. The first temperature control unit is electrically connected to the second heater and controls the temperature of the second heater. The second temperature control unit is electrically connected to the second nozzle unit, and controls the temperature of the second nozzle unit by supplying current to the second nozzle unit. The second temperature control unit controls the temperature of the first nozzle section and the second nozzle section separately by supplying current to the first nozzle section and the second nozzle section separately.

7. The injection molding apparatus according to claim 6, characterized in that, The second temperature control unit controls the temperature of the first nozzle section and the temperature of the second nozzle section in a manner that makes the temperature of the first nozzle section and the temperature of the second nozzle section different from each other.

8. The injection molding apparatus according to claim 6, characterized in that, The second temperature control unit controls the temperature of the first nozzle section by executing multiple controls, including the first control and the second control. The first control is to supply current to the first nozzle section so that the temperature of the first nozzle section reaches a first temperature. The second control involves supplying current to the first nozzle section to raise its temperature to a second temperature higher than the first temperature. The second temperature control unit controls the temperature of the second nozzle unit by executing multiple controls, including a third control and a fourth control. The third control is to supply current to the second nozzle section so that the temperature of the second nozzle section reaches a third temperature. The fourth control is to supply current to the second nozzle section so that the temperature of the second nozzle section reaches a fourth temperature that is higher than the third temperature. The second temperature control unit controls the temperature in a manner that makes the start timing of the first control in the first nozzle unit and the start timing of the third control in the second nozzle unit different from the start timing of the second control in the first nozzle unit and the start timing of the fourth control in the second nozzle unit.

9. An injection molding method, characterized in that, The molded part is injection molded using an injection molding device. The injection molding apparatus includes: The plasticizing department plasticizes materials to produce plasticized materials; A first flow path, connected to the plasticizing section, is used to allow the plasticizing material to flow; and A first hot runner has a first nozzle and a first heater. The first nozzle is connected to the first flow path and injects the plasticizing material. The first heater heats the plasticizing material in the first flow path. The first nozzle section is made of metal. The injection molding method comprises: The first step involves controlling the temperature of the first heater; and The second step involves controlling the temperature of the first nozzle section by supplying current to the first nozzle section.

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