Injection molding machine

Abstract

The present invention provides an injection molding machine capable of supplying molten resin. The injection molding machine comprises: an injection device to which molten resin is supplied; and a control device for controlling the injection device, wherein the control device comprises: a judgment unit for judging whether molten resin can be supplied to the injection device; and a processing unit for processing the supply of molten resin according to the judgment result of the judgment unit.

Description

Technical Field

[0001] This application claims priority based on Japanese Patent Application No. 2020-130985 filed on Jul. 31, 2020. The entire contents of the Japanese Patent Application are incorporated herein by reference.

[0002] The invention relates to an injection molding machine. Background Art

[0003] There is known an injection device for injecting molten resin into a mold device.

[0004] Patent document 1 discloses an injection device, which comprises: a first cylinder; a first movable part that moves the molding material in the first cylinder; a second cylinder that supplies the molding material from the first cylinder; a second movable part that moves the molding material in the second cylinder; a nozzle that injects the molding material into a mold device; and a switching part that switches the flow direction of the molding material between the first cylinder, the second cylinder and the nozzle.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-150810

[0006] In an injection molding machine system that supplies molten resin as a molding material to an injection device, an extruder can be used as a molten resin supply device. Here, the extruder continuously supplies molten resin. Therefore, the molten resin may overflow in the injection device. Summary of the invention

[0007] Therefore, an object of the present invention is to provide an injection molding machine capable of supplying molten resin.

[0008] An injection molding machine of one embodiment comprises: an injection device to which molten resin is supplied; and a control device to control the injection device, wherein the control device comprises: a judgment unit to judge whether molten resin can be supplied to the injection device; and a processing unit to process the supply of molten resin according to the judgment result of the judgment unit.

[0009] Effects of the Invention

[0010] According to the present invention, it is possible to provide an injection molding machine capable of supplying molten resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a configuration diagram of the injection molding machine system according to the first embodiment.

[0012] Figure 2 It is a schematic cross-sectional view of the injection device according to the first embodiment.

[0013] Figure 3This is a flowchart showing the operation of the injection device according to the first embodiment.

[0014] Figure 4 It is a diagram showing a state of the injection device according to the first embodiment in a metering process.

[0015] Figure 5 This is a diagram showing a state of the injection device according to the first embodiment after the metering step is completed.

[0016] Figure 6 It is a diagram showing a state of the injection device according to the first embodiment during a filling process.

[0017] Figure 7 It is a diagram showing a state of the injection device according to the first embodiment in a pressure holding step.

[0018] Figure 8 This is a flowchart showing the operation of the discharge valve in the injection device according to the first embodiment.

[0019] Fig. 9 It is a diagram showing a state of the injection device according to the first embodiment when the discharge valve is in the second state.

[0020] Fig.10 It is a schematic cross-sectional view of an injection device according to a second embodiment.

[0021] Fig.11 It is a diagram showing a state of the injection device according to the second embodiment in a metering process.

[0022] Fig.12 This is a diagram showing a state of the injection device according to the second embodiment after the metering step is completed.

[0023] Fig.13 It is a diagram showing a state of the injection device according to the second embodiment during a filling process.

[0024] Fig.14 It is a diagram showing a state of the injection device according to the second embodiment in a pressure holding step.

[0025] Fig.15 This is a flowchart showing the operation of the supply and discharge valve in the injection device according to the second embodiment.

[0026] Fig.16 It is a diagram showing a state of the injection device according to the second embodiment when the discharge valve is in the second state.

[0027] In the figure: S-injection molding machine system, 1-injection molding machine, 3, 3A-injection device, 4, 80-control device (control unit), 6-molten resin supply device, 7-molten resin supply channel, 8-control valve, 10-tank cylinder (first cylinder body), 12-first plunger (first movable part), 15-first plunger driving part (first driving part), 16-advance and retract motor, 17-encoder, 18-pressure detection part, 20-injection cylinder (second cylinder body), 22-second plunger (second movable part), 25-second plunger driving part (second driving part), 2 6-advance and retract motor, 27-encoder, 28-pressure detecting unit, 30-molten resin supply unit (supply unit), 35-connecting unit, 40-nozzle, 50-direction conversion valve (switching unit), 51-valve body, 52-valve core, 60-discharge unit, 70-discharge valve (discharge switching unit), 70A-supply and discharge valve (supply / discharge switching unit), 71-valve body, 72, 72A-valve core, 73-connecting port (supply channel), 74-connecting port (supply channel), 75-connecting port (supply channel), 76-connecting port (discharge channel). DETAILED DESCRIPTION

[0028] Hereinafter, the mode for implementing the present invention will be described with reference to the accompanying drawings. In each of the drawings, the same or corresponding structures are denoted by the same or corresponding symbols, and the description thereof will be omitted.

[0029] <Injection molding machine system S>

[0030] use Figure 1 The injection molding machine system S according to the first embodiment will be described. Figure 1 It is a configuration diagram of the injection molding machine system S according to the first embodiment.

[0031] The injection molding machine system S includes an injection molding machine 1 , a molten resin supply device 6 , a molten resin supply passage 7 , and a control valve 8 .

[0032] The injection molding machine 1 includes a clamping device 2 for opening and closing a mold device (not shown), an injection device 3 for injecting a molding material into a cavity space of the mold device, an ejection device (not shown) for ejecting a molded product molded by the mold device, a moving device (not shown) for moving the injection device 3 forward and backward relative to the mold device, a control device 4 for controlling the various components of the injection molding machine 1, and a frame 5 for supporting the various components of the injection molding machine 1.

[0033] The mold clamping device 2 performs a mold closing process, a pressurizing process, a mold clamping process, a depressurizing process, and a mold opening process under the control of the control device 4. In the mold closing process, the control device 4 controls the mold clamping device 2 to make the movable mold contact the fixed mold. In the pressurizing process, the control device 4 controls the mold clamping device 2 to generate a mold clamping force. In the mold closing process, the control device 4 controls the mold clamping device 2 to maintain the mold clamping force generated in the pressurizing process. In the depressurizing process, the control device 4 controls the mold clamping device 2 to reduce the mold clamping force. In the mold opening process, the control device 4 controls the mold clamping device 2 to separate the movable mold from the fixed mold.

[0034] The injection device 3 performs a metering process, a filling process, a pressure holding process, etc. under the control of the control device 4. The filling process and the pressure holding process can be collectively referred to as an injection process. In the metering process, the control device 4 controls the injection device 3 so that a predetermined amount of molten resin is accumulated on the second plunger 22 (see the following description). Figure 2 ). In the filling process, the control device 4 controls the injection device 3 to fill the molten resin accumulated in front of the second plunger 22 into the cavity space in the mold device. In the pressure holding process, the control device 4 controls the injection device 3 to push the second plunger 22 forward, maintain the pressure of the molding material in the front end of the second plunger 22 (holding pressure) at the set pressure, and Figure 2 ) is pushed toward the mold device. In addition, the injection molding machine 1 starts the cooling process after the pressure holding process. In the cooling process, the molding material in the cavity space is solidified. In order to shorten the molding cycle time, a metering process can be performed in the cooling process.

[0035] The ejector device (not shown) performs an ejection process under the control of the control device 4. In the ejection process, the control device 4 controls the ejector device to move the ejector rod (not shown) from the standby position to the ejection position to eject the molded product. Then, the ejector rod is retracted to the original standby position.

[0036] The moving device (not shown) moves the injection device 3 forward and backward relative to the mold device. When the injection device 3 is moved forward toward the mold device, the nozzle 40 of the injection device 3 is pressed against the fixed mold of the mold device. When the injection device 3 is moved backward, the nozzle 40 of the injection device 3 is separated from the fixed mold of the mold device.

[0037] The control device 4 repeatedly manufactures molded products by repeatedly performing metering steps, mold closing steps, pressure increasing steps, mold closing steps, filling steps, pressure holding steps, cooling steps, pressure releasing steps, mold opening steps, and ejection steps. A series of actions for obtaining molded products, such as the actions from the start of a metering step to the start of the next metering step, are also referred to as "injection" or "molding cycle". In addition, the time required for one injection is also referred to as "molding cycle time" or "cycle time".

[0038] A molding cycle includes, for example, a metering process, a mold closing process, a pressure increasing process, a mold closing process, a filling process, a pressure holding process, a cooling process, a pressure releasing process, a mold opening process, and an ejection process in sequence. The order here is the order in which each process starts. The filling process, the pressure holding process, and the cooling process are performed during the mold closing process. The start of the mold closing process may also coincide with the start of the filling process. The end of the pressure releasing process coincides with the start of the mold opening process.

[0039] In order to shorten the molding cycle time, multiple processes can be performed simultaneously. For example, the metering process can be performed during the cooling process of the previous molding cycle, or during the mold closing process. In this case, the mold closing process can be performed at the beginning of the molding cycle. In addition, the filling process can be started during the mold closing process. In addition, the ejection process can be started during the mold opening process. When the nozzle 40 of the opening and closing injection device 3 is set (refer to the following Figure 2 ) is closed, the mold opening process can be started during the metering process. This is because even if the mold opening process is started during the metering process, as long as the opening and closing valve (not shown) closes the flow path of the nozzle 40 of the injection device 3, the molding material will not leak from the nozzle 40 of the injection device 3.

[0040] In addition, a primary molding cycle may include processes other than the metering process, the mold closing process, the pressure increasing process, the mold clamping process, the filling process, the pressure holding process, the cooling process, the pressure releasing process, the mold opening process, and the ejection process.

[0041] The molten resin supply device 6 is a device for supplying molten resin (molding material). The molten resin supply device 6 may be, for example, an extruder that melts and extrude a solid molding material (for example, pellets, etc.).

[0042] The molten resin supply passage 7 is a flow path for supplying molten resin from the molten resin supply device 6 to the injection device 3. The molten resin supply passage 7 may include, for example, a pipe through which the molten resin flows, an insulating material covering the pipe, a heating device for keeping the molten resin flowing in the pipe warm, and the like.

[0043] The control valve 8 is provided in the molten resin supply passage 7 to control the supply of the molten resin to the injection device 3. The control valve 8 may be, for example, an on-off valve. The control valve 8 is controlled by the control device 4 of the injection molding machine 1 (control device 80 described later).

[0044] In addition, the injection molding machine system S according to the first embodiment shows a structure in which one injection molding machine 1 is connected to the molten resin supply passage 7, but the present invention is not limited thereto, and a structure in which a plurality of injection molding machines 1 are connected may be used. In addition, the injection molding machine system S according to the first embodiment shows a structure in which one molten resin supply device 6 is connected to the molten resin supply passage 7, but the present invention is not limited thereto, and a structure in which a plurality of molten resin supply devices 6 are connected may be used.

[0045] <Injection device 3 according to first embodiment>

[0046] Next, use Figure 2 The injection device 3 of the injection molding machine 1 according to the first embodiment will be described further. Figure 2 : is a cross-sectional schematic diagram of the injection device 3 involved in the first embodiment. Figure 2 This is a cross-sectional view perpendicular to the rotation center line of the valve body 52 .

[0047] The injection device 3 includes a tank cylinder (first cylinder body) 10, a first plunger (first movable part) 12, a first plunger driving part (first driving part) 15, an injection cylinder (second cylinder body) 20, a second plunger (second movable part) 22, a second plunger driving part (second driving part) 25, a molten resin supply part (supply part) 30, a connecting part 35, a nozzle 40, a direction conversion valve (switching part) 50, a discharge part 60, a discharge valve (supply / discharge switching part) 70 and a control device (control part) 80 (4).

[0048] The liquid molding material (molten resin) is supplied from the molten resin supply unit 30 to the inside of the tank cylinder 10. The tank cylinder 10 is provided with a heating source such as a heating device on its outer periphery.

[0049] The first plunger 12 is disposed inside the tank cylinder 10 and moves the molding material inside the tank cylinder 10. The first plunger 12 is disposed inside the tank cylinder 10 so as to be able to move forward and backward.

[0050] The first plunger driving unit 15 operates the first plunger 12. The first plunger driving unit 15 includes an advance / retract motor 16, an encoder 17, and a pressure detection unit 18.

[0051] The advance / retract motor 16 advances / retracts the first plunger 12. A motion conversion mechanism is provided between the first plunger 12 and the advance / retract motor 16 to convert the rotational motion of the advance / retract motor 16 into the linear motion of the first plunger 12. The motion conversion mechanism is composed of, for example, a ball screw or the like.

[0052] The encoder 17 detects the rotation of the advance / retract motor 16 and sends a signal indicating the detection result to the control device 80. The control device 80 calculates the position and moving speed of the first plunger 12 based on the detection value of the encoder 17. The detection result of the encoder 17 is used for controlling and monitoring the position of the first plunger 12, the moving speed of the first plunger 12, etc.

[0053] The pressure detection unit 18 is provided in the force transmission path between the advance / retract motor 16 and the first plunger 12, and detects the force transmitted between the advance / retract motor 16 and the first plunger 12, and sends a signal indicating the detection result to the control device 80. The detected force is converted into the pressure of the first plunger 12 by the control device 80. The detection result of the pressure detection unit 18 is used for controlling and monitoring the pressure received by the first plunger 12 from the molding material, the back pressure on the first plunger 12, the pressure acting on the molding material from the first plunger 12, and the like.

[0054] The molding material is supplied from the molten resin supply unit 30 and the tank cylinder 10 to the interior of the injection cylinder 20. A heating source such as a heating device is provided on the outer periphery of the injection cylinder 20.

[0055] The second plunger 22 is disposed inside the injection cylinder 20 and moves the molding material inside the injection cylinder 20. The second plunger 22 is disposed inside the injection cylinder 20 so as to be able to move forward and backward.

[0056] The second plunger driving unit 25 operates the second plunger 22. The second plunger driving unit 25 includes an advance / retract motor 26.

[0057] The advance / retract motor 26 advances / retracts the second plunger 22. A motion conversion mechanism is provided between the second plunger 22 and the advance / retract motor 26 to convert the rotational motion of the advance / retract motor 26 into the linear motion of the second plunger 22. The motion conversion mechanism is composed of, for example, a ball screw or the like.

[0058] The encoder 27 detects the rotation of the advance / retract motor 26 and sends a signal indicating the detection result to the control device 80. The control device 80 calculates the position and moving speed of the second plunger 22 based on the detection value of the encoder 27. The detection result of the encoder 27 is used for controlling and monitoring the position of the second plunger 22, the moving speed of the second plunger 22, etc.

[0059] The pressure detection unit 28 is provided in the force transmission path between the advance / retract motor 26 and the second plunger 22, and detects the force transmitted between the advance / retract motor 26 and the second plunger 22, and sends a signal indicating the detection result to the control device 80. The detected force is converted into the pressure of the second plunger 22 by the control device 80. The detection result of the pressure detection unit 28 is used for controlling and monitoring the pressure received by the second plunger 22 from the molding material, the back pressure on the second plunger 22, and the pressure acting on the molding material from the second plunger 22.

[0060] The molten resin supply unit 30 and the molten resin supply passage 7 (refer to Figure 1 ) is connected, and molten resin is continuously supplied from the molten resin supply device 6.

[0061] The connection portion 35 connects the molten resin supply portion 30 , the tank cylinder 10 , and the direction switching valve 50 , and allows the molten resin to flow.

[0062] The nozzle 40 injects the molding material supplied from the direction change valve 50 into the mold device. The liquid molding material filled in the mold device is solidified to be formed into a molded product.

[0063] The direction switching valve 50 switches the flow direction of the molding material between the connection part 35 (tank cylinder 10, molten resin supply part 30), the injection cylinder 20 and the nozzle 40. The direction switching valve 50 includes a valve body 51, a valve element 52 and a valve element driving part (not shown).

[0064] The valve body 51 has a supply side connection port 53, an injection cylinder connection port 54, and a nozzle connection port 55. The supply side connection port 53 communicates with the inside of the molten resin supply unit 30 and the tank cylinder 10. The injection cylinder connection port 54 communicates with the inside of the injection cylinder 20. The nozzle connection port 55 communicates with the inside of the nozzle 40.

[0065] The injection cylinder connection port 54 and the nozzle connection port 55 are provided, for example, on the opposite sides of the rotation center line of the valve core 52. On the other hand, the supply side connection port 53 is provided, for example, at a position substantially equidistant from both the injection cylinder connection port 54 and the nozzle connection port 55 along the outer periphery of the valve core 52. That is, the supply side connection port 53 is provided along a predetermined direction ( Figure 2 The injection cylinder connection port 54, the supply side connection port 53 and the nozzle connection port 55 are arranged at intervals of 90 degrees in this order (counterclockwise in the middle).

[0066] The valve core 52 rotates inside the valve body 51, thereby switching to the first state (see the following description). Figure 4 ) and the second state (reference Figures 5 to 7 ). When the valve core 52 is in the first state, the supply side connection port 53 and the injection cylinder connection port 54 are connected, and the nozzle connection port 55 is blocked. On the other hand, when the valve core 52 is in the second state, the injection cylinder connection port 54 and the nozzle connection port 55 are connected, and the supply side connection port 53 is blocked. Thus, in the first state, molten resin can be supplied from the molten resin supply unit 30 and the tank cylinder 10 to the injection cylinder 20. In the second state, molten resin can be supplied from the injection cylinder 20 to the nozzle 40.

[0067] In addition, the state of the valve core 52 is not limited to the first state and the second state. For example, the valve core 52 can be in a state where the supply-side connection port 53, the injection cylinder connection port 54, and the nozzle connection port 55 are blocked at the same time. In addition, the valve core 52 can be in a state where the supply-side connection port 53 and the nozzle connection port 55 are connected and the injection cylinder connection port 54 is blocked.

[0068] The valve element drive unit operates the valve element 52. Specifically, the valve element drive unit rotates the valve element 52 inside the valve body 51, thereby switching between the first state and the second state.

[0069] The discharge unit 60 discharges the molten resin to the outside of the injection device 3 .

[0070] The discharge valve 70 is a valve for opening and closing the discharge portion 60. Figure 2 In the example shown, the discharge valve 70 is configured as a direction switching valve. The discharge valve 70 switches the flow direction of the molding material between the molten resin supply unit 30, the tank cylinder 10, the connection unit 35 (direction switching valve 50), and the discharge unit 60. The discharge valve 70 includes a valve body 71, a valve core 72, and a valve core driving unit (not shown).

[0071] The valve body 71 has connection ports 73 to 76. The connection port 73 is connected to the inside of the molten resin supply unit 30. The connection port 74 is connected to the inside of the tank cylinder 10. The connection port 75 is connected to the inside of the connection unit 35. The connection port 76 is connected to the inside of the discharge unit 60. The connection ports 73 to 76 are connected in a predetermined direction ( Figure 2 The connection ports 73, 74, 75, and 76 are arranged at intervals of 90 degrees in the order of clockwise direction. The connection ports 73 to 75 serve as supply passages for supplying molten resin from the molten resin supply section 30 to the cylinder (tank cylinder 10 and / or injection cylinder 20). The connection port 76 serves as a discharge passage for discharging molten resin from the molten resin supply section 30 to the discharge section 60.

[0072] The valve core 72 rotates inside the valve body 71, thereby switching to the first state (see the following description). Figures 4 to 7 ) and the second state (see below Fig. 9 ). When the valve body 72 is in the first state, the connection ports 73 to 75 are connected, and the connection port 76 is blocked. On the other hand, when the valve body 72 is in the second state, the connection ports 73, 74, and 76 are connected, and the connection port 75 is blocked.

[0073] The state of the valve body 72 is not limited to the first state and the second state. For example, the valve body 72 can be in a state of communicating with the connection ports 73, 75, and 76 and blocking the connection port 74. Furthermore, the valve body 72 can be in a state of communicating with the connection ports 74 to 76 and blocking the connection port 73.

[0074] The valve element drive unit operates the valve element 72. Specifically, the valve element drive unit rotates the valve element 72 inside the valve body 71, thereby switching between the first state and the second state.

[0075] The control device 80 controls the first plunger drive unit 15, the second plunger drive unit 25, the direction change valve 50, the discharge valve 70, etc. In addition, the control device 80 may be configured as a part of the control device 4 that controls each component of the injection molding machine 1. In addition, the control device 80 may be provided separately from the control device 4.

[0076] The control device 80 includes a judgment unit 81, a processing unit 82, and a flow path switching processing unit 83. The judgment unit 81 judges whether the molten resin can be supplied to the injection device 3. That is, the judgment unit 81 judges whether the molten resin can be received in the cylinder (tank cylinder 10 and / or injection cylinder 20) of the injection device 3. The processing unit 82 processes the supply of the molten resin according to the judgment result of the judgment unit 81. The flow path switching processing unit 83 controls the first plunger driving unit 15, the second plunger driving unit 25 and the direction switching valve 50 to control the flow of the molten resin.

[0077] <Operation of the injection device 3 according to the first embodiment>

[0078] Next, use Figures 3 to 7 The operation of the injection device 3 according to the first embodiment will be described. Figure 3 is a flowchart showing the operation of the injection device 3 according to the first embodiment. Figure 3 In the description of the operation shown in the flow chart, the valve core 72 of the discharge valve 70 is in the first state. Figures 4 to 7 (and the following Fig. 9 ), the flow of the molten resin is indicated by a dotted arrow, and the moving directions of the first plunger 12 and the second plunger 22 are indicated by a shaded arrow. Figure 3 In the flowchart shown, the description is given assuming that the determination unit 81 determines that the molten resin can be supplied to the injection device 3 .

[0079] Figure 41 is a diagram showing the state of the injection device 3 according to the first embodiment in the metering process. In step S101, the flow path switching processing unit 83 of the control device 80 performs the metering process. The flow path switching processing unit 83 of the control device 80 controls the valve core driving unit of the direction switching valve 50 so that the valve core 52 of the direction switching valve 50 is in the first state. The molten resin supplied from the molten resin supply unit 30 is accumulated in front of the second plunger 22 in the injection cylinder 20 via the molten resin supply unit 30, the discharge valve 70, the connection unit 35 and the direction switching valve 50. In addition, the flow path switching processing unit 83 of the control device 80 drives the advance and retreat motor 16 to advance the first plunger 12. The molten resin accumulated in front of the first plunger 12 in the tank cylinder 10 is accumulated in front of the second plunger 22 in the injection cylinder 20 via the discharge valve 70, the connection unit 35 and the direction switching valve 50.

[0080] By accumulating the molten resin in front of the second plunger 22 in the injection cylinder 20, the second plunger 22 in the injection cylinder 20 retreats. In addition, the flow path switching processing unit 83 of the control device 80 detects the position of the second plunger 22 based on the detection value of the encoder 27. Here, in order to suppress the rapid retreat of the second plunger 22, the flow path switching processing unit 83 of the control device 80 may also drive the advance / retract motor 26 based on the detection value of the pressure detection unit 28 to apply a set back pressure to the second plunger 22.

[0081] Figure 5 : is a diagram showing the state of the injection device 3 involved in the first embodiment after the metering process is completed. If the second plunger 22 retreats to a predetermined position and a predetermined amount of molten resin is accumulated in front of the second plunger 22, the flow path switching processing unit 83 of the control device 80 stops the drive of the advance and retreat motor 16 and stops the drive of the advance and retreat motor 26. In addition, the flow path switching processing unit 83 of the control device 80 controls the valve core driving unit of the direction switching valve 50 to make the valve core 52 of the direction switching valve 50 in the second state. The molten resin supplied from the molten resin supply unit 30 is accumulated in front of the first plunger 12 in the tank cylinder 10 via the molten resin supply unit 30 and the discharge valve 70. By accumulating the molten resin in front of the first plunger 12 in the tank cylinder 10, the first plunger 12 in the tank cylinder 10 retreats. In addition, the flow path switching processing unit 83 of the control device 80 detects the position of the first plunger 12 based on the detection value of the encoder 17. Here, in order to suppress the rapid retreat of the first plunger 12, the flow path switching processing unit 83 of the control device 80 may also drive the advance / retract motor 16 according to the detection value of the pressure detection unit 18 to apply a set back pressure to the first plunger 12. In addition, the process of placing the valve core 52 of the direction switching valve 50 in the second state so that the molten resin supplied from the molten resin supply unit 30 is accumulated in front of the first plunger 12 in the tank cylinder 10 is also called a tank plunger metering process.

[0082] Figure 61 is a diagram showing the state of the injection device 3 involved in the first embodiment in the filling process. In step S102, the flow path switching processing unit 83 of the control device 80 performs the filling process. The flow path switching processing unit 83 of the control device 80 drives the advance and retreat motor 26 to advance the second plunger 22 to a predetermined position. In addition, the flow path switching processing unit 83 of the control device 80 detects the position of the second plunger 22 based on the detection value of the encoder 27. The molten resin accumulated in front of the second plunger 22 in the injection cylinder 20 is filled into the cavity space in the mold device via the direction conversion valve 50 and the nozzle 40. In addition, in the filling process, the molten resin supplied from the molten resin supply unit 30 is accumulated in front of the first plunger 12 in the tank cylinder 10 via the molten resin supply unit 30 and the discharge valve 70 (tank plunger metering process).

[0083] Figure 7 1 is a diagram showing the state of the injection device 3 involved in the first embodiment in the pressure holding process. In step S103, the flow path switching processing unit 83 of the control device 80 performs the pressure holding process. In addition, the flow path switching processing unit 83 of the control device 80 controls the advance and retreat motor 26 according to the detection value of the pressure detection unit 28, pushes the second plunger 22 forward, maintains the pressure (holding pressure) of the molten resin in the front end of the second plunger 22 at the set pressure, and pushes the molten resin remaining in the injection cylinder 20 toward the mold device. In addition, in the pressure holding process, the molten resin supplied from the molten resin supply unit 30 is accumulated in front of the first plunger 12 in the tank cylinder 10 via the molten resin supply unit 30 and the discharge valve 70 (tank plunger metering process). In addition, the flow path switching processing unit 83 of the control device 80 detects the position of the first plunger 12 according to the detection value of the encoder 17.

[0084] After the pressure holding process is completed, the flow path switching processing unit 83 of the control device 80 rotates the valve core 52 of the direction switching valve 50 before the molding material is supplied from the storage cylinder 10 to the injection cylinder 20 in the next metering process, so that the state of the valve core 52 changes from Figure 7 The second state shown returns to Figure 4 The first state is shown.

[0085] The flow path switching processing unit 83 of the control device 80 repeatedly performs the metering process, the filling process, the pressure holding process, and the like, whereby the injection molding machine 1 repeatedly manufactures molded products.

[0086] In other words, the control device 80 of the injection device 3 according to the first embodiment repeats a tank plunger metering process of supplying molten resin from the molten resin supply unit 30 to the tank cylinder 10 to accumulate molten resin in the tank cylinder 10, a metering process of supplying molten resin from the molten resin supply unit 30 and the tank cylinder 10 to the injection cylinder 20 to accumulate molten resin in the injection cylinder 20, a filling process of filling the cavity space in the mold device with molten resin from the injection cylinder 20, and a pressure holding process of maintaining the pressure of the molten resin at a set pressure. In addition, during the injection process (filling process, pressure holding process), the tank plunger metering process of the next molding cycle is performed simultaneously.

[0087] As described above, the injection device 3 involved in the first embodiment can be used in an injection molding machine system S that continuously supplies molten resin from the molten resin supply device 6 to the molten resin supply part 30. In the tank plunger metering process, the molten resin can be accumulated in the tank cylinder 10, thereby preventing the overflow of the molten resin.

[0088] <Operation of the discharge valve 70>

[0089] Next, use Figures 8 to 9 The operation of the discharge valve 70 of the injection device 3 according to the first embodiment will be described. Figure 8 1 is a flowchart showing the operation of the discharge valve 70 in the injection device 3 according to the first embodiment. Figure 8 During the process, the valve core 72 of the discharge valve 70 is in the first state.

[0090] In step S201, the determination unit 81 of the control device 80 determines whether the directional control valve 50 is in the second state. When the directional control valve 50 is not in the second state (S201 "No"), the processing of the control device 80 repeats step S201. When the directional control valve 50 is in the second state (S201 "Yes"), the processing of the control device 80 goes to step S202.

[0091] In step S202, the determination unit 81 of the control device 80 determines whether the supply stop condition is satisfied. Here, when the supply stop condition is satisfied, the determination unit 81 determines that the cylinder (tank cylinder 10 and / or injection cylinder 20) of the injection device 3 cannot receive the molten resin. The supply stop condition refers to a condition for stopping the supply of the molten resin from the molten resin supply unit 30 to the tank cylinder 10. In other words, it is a condition for discharging the molten resin supplied from the molten resin supply unit 30 from the discharge unit 60. For example, the determination unit 81 of the control device 80 detects the position of the first plunger 12 through the encoder 17, and when the first plunger 12 retreats to a predetermined position (for example, a retreat limit), it determines that the supply stop condition is satisfied. This is because the first plunger 12 retreats to a predetermined position, thereby reducing the remaining capacity that can be stored in the tank cylinder 10, and the molten resin may overflow from the tank cylinder 10. In addition, when the cycle time exceeds a predetermined time, the determination unit 81 of the control device 80 may also determine that the supply stop condition is satisfied. The tank cylinder 10 is supplied with molten resin, and the molten resin accumulated in the tank cylinder 10 increases as time passes. This is because the cycle time exceeds the specified time, and thus the remaining capacity that can be accumulated in the tank cylinder 10 becomes less, so that the molten resin may overflow from the tank cylinder 10. In addition, the judgment unit 81 of the control device 80 can also determine whether the supply stop condition is met based on the detection value of the pressure detection unit 18. When the supply stop condition is not met (S202 "No"), the processing of the control device 80 returns to step S201. When the supply stop condition is met (S202 "Yes"), the processing of the control device 80 goes to step S203.

[0092] Fig. 9 2 is a diagram showing the state of the injection device 3 according to the first embodiment when the discharge valve 70 is in the second state. In step S203, the processing unit 82 of the control device 80 controls the valve core driving unit of the discharge valve 70 so that the valve core 72 of the discharge valve 70 is in the second state. The molten resin supplied from the molten resin supply unit 30 is discharged from the discharge unit 60 to the outside of the injection device 3 via the molten resin supply unit 30 and the discharge valve 70.

[0093] In step S204, the determination unit 81 of the control device 80 determines whether the operation of the injection device 3 starts the metering process (see Figure 3 Step S101). When the metering process has not started (S204: No), the control device 80 returns to step S203. When the metering process has started (S204: Yes), the control device 80 proceeds to step S205.

[0094] In step S205, the processing unit 82 of the control device 80 controls the valve element driving unit of the discharge valve 70 so that the valve element 72 of the discharge valve 70 is in the first state. Then, the processing of the control device 80 returns to step S201.

[0095] Thus, according to the injection device 3 involved in the first embodiment, when it is determined that the cylinder body (tank cylinder 10 and / or injection cylinder 20) of the injection device 3 cannot receive the molten resin, the molten resin supplied from the molten resin supply unit 30 is discharged from the discharge unit 60 to the outside of the injection device 3. Thus, the overflow of the molten resin in the cylinder body (tank cylinder 10 and / or injection cylinder 20) can be prevented, and the damage of the injection device 3 can be prevented.

[0096] <Injection Device 3A According to Second Embodiment>

[0097] Next, use Fig.10 An injection device 3A of an injection molding machine according to a second embodiment will be described. Fig.10 : is a cross-sectional schematic diagram of the injection device 3A involved in the second embodiment. Fig.10 This is a cross-sectional view perpendicular to the rotation center line of the valve body 52 .

[0098] Fig.10 The injection device 3A according to the second embodiment shown in FIG. Figure 2 The difference from the injection device 3 according to the first embodiment shown is that a supply discharge valve 70A is provided instead of the discharge valve 70. Specifically, the connection of the flow path in the valve core 72A is different. The other structures are the same as those of the injection device 3 according to the first embodiment, and repeated description is omitted.

[0099] The supply and discharge valve 70A is a valve for switching the supply and discharge of molten resin. Fig.10 In the example shown, the supply and discharge valve 70A is configured as a direction switching valve. The supply and discharge valve 70A switches the flow direction of the molding material between the molten resin supply unit 30, the tank cylinder 10, the connection unit 35 (direction switching valve 50) and the discharge unit 60. The supply and discharge valve 70A includes a valve body 71, a valve core 72A and a valve core driving unit (not shown).

[0100] The valve body 71 has connection ports 73 to 76. The connection port 73 is connected to the inside of the molten resin supply unit 30. The connection port 74 is connected to the inside of the tank cylinder 10. The connection port 75 is connected to the inside of the connection unit 35. The connection port 76 is connected to the inside of the discharge unit 60. The connection ports 73 to 76 are connected in a predetermined direction ( Fig.10The connection ports 73, 74, 75, and 76 are arranged at intervals of 90 degrees in the order of clockwise direction. The connection ports 73 to 75 serve as supply passages for supplying molten resin from the molten resin supply section 30 to the cylinder (tank cylinder 10 and / or injection cylinder 20). The connection port 76 serves as a discharge passage for discharging molten resin from the molten resin supply section 30 to the discharge section 60.

[0101] The valve core 72A rotates inside the valve body 71, thereby switching to the first state (see the following description). Figures 12-14 ) and the second state (see below Fig.11 , 16 ). When the valve core 72A is in the first state, the connection port 73 and the connection port 74 are connected, and the connection port 75 and the connection port 76 are connected. On the other hand, when the valve core 72A is in the second state, the connection port 73 and the connection port 76 are connected, and the connection port 74 and the connection port 75 are connected. Thus, in the first state, the molten resin can be supplied from the molten resin supply part 30 to the tank cylinder 10. In the second state, the molten resin can be supplied from the tank cylinder 10 to the injection cylinder 20, and the molten resin can be discharged from the molten resin supply part 30 to the discharge part 60.

[0102] The valve body drive unit operates the valve body 72A. Specifically, the valve body drive unit rotates the valve body 72A inside the valve body 71 to switch between the first state and the second state.

[0103] <Operation of Injection Device 3A According to Second Embodiment>

[0104] Next, refer to Figure 3 And use Figures 11 to 14 The operation of the injection device 3A according to the second embodiment will be described. Figures 11 to 14 (and the following Fig.16 ), the flow of the molten resin is indicated by the dotted arrows, and the moving directions of the first plunger 12 and the second plunger 22 are indicated by the shaded arrows. Figure 3 In the flowchart shown, the description is given assuming that the determination unit 81 determines that the molten resin can be supplied to the injection device 3A.

[0105] Fig.111 is a diagram showing the state of the injection device 3A involved in the second embodiment in the metering process. In step S101, the flow path switching processing unit 83 of the control device 80 performs the metering process. The flow path switching processing unit 83 of the control device 80 controls the valve core driving unit of the direction switching valve 50 so that the valve core 52 of the direction switching valve 50 is in the first state. In addition, the flow path switching processing unit 83 of the control device 80 controls the valve core driving unit of the supply and discharge valve 70A so that the valve core 72A of the supply and discharge valve 70A is in the second state. In addition, the flow path switching processing unit 83 of the control device 80 drives the advance and retreat motor 16 to advance the first plunger 12. The molten resin accumulated in front of the first plunger 12 in the tank cylinder 10 is accumulated in front of the second plunger 22 in the injection cylinder 20 via the supply and discharge valve 70A, the connecting portion 35 and the direction switching valve 50. On the other hand, the molten resin supplied from the molten resin supply unit 30 is discharged from the discharge unit 60 to the outside of the injection device 3 via the molten resin supply unit 30 and the supply and discharge valve 70A.

[0106] By accumulating the molten resin in front of the second plunger 22 in the injection cylinder 20, the second plunger 22 in the injection cylinder 20 retreats. In addition, the flow path switching processing unit 83 of the control device 80 detects the position of the second plunger 22 based on the detection value of the encoder 27. Here, in order to suppress the rapid retreat of the second plunger 22, the flow path switching processing unit 83 of the control device 80 may also drive the advance / retract motor 26 based on the detection value of the pressure detection unit 28 to apply a set back pressure to the second plunger 22.

[0107] Fig.123A is a diagram showing the state of the injection device 3A involved in the second embodiment after the metering process is completed. If the second plunger 22 retreats to a predetermined position and a predetermined amount of molten resin is accumulated in front of the second plunger 22, the flow path switching processing unit 83 of the control device 80 stops the drive of the advance / retract motor 16 and stops the drive of the advance / retract motor 26. In addition, the flow path switching processing unit 83 of the control device 80 controls the valve core driving unit of the direction switching valve 50 so that the valve core 52 of the direction switching valve 50 is in the second state. In addition, the flow path switching processing unit 83 of the control device 80 controls the valve core driving unit of the supply / discharge valve 70A so that the valve core 72A of the supply / discharge valve 70A is in the first state. The molten resin supplied from the molten resin supply unit 30 is accumulated in front of the first plunger 12 in the tank cylinder 10 via the molten resin supply unit 30 and the supply / discharge valve 70A. By accumulating the molten resin in front of the first plunger 12 in the tank cylinder 10, the first plunger 12 in the tank cylinder 10 retreats. In addition, the flow path switching processing unit 83 of the control device 80 detects the position of the first plunger 12 based on the detection value of the encoder 17. Here, in order to suppress the rapid retreat of the first plunger 12, the flow path switching processing unit 83 of the control device 80 may also drive the advance and retreat motor 16 based on the detection value of the pressure detection unit 18 to apply a set back pressure to the first plunger 12. In addition, the process of placing the valve core 52 of the direction switching valve 50 in the second state so that the molten resin supplied from the molten resin supply unit 30 is accumulated in front of the first plunger 12 in the tank cylinder 10 is also called a tank plunger metering process.

[0108] Fig.13 : is a diagram showing the state of the injection device 3A involved in the second embodiment in the filling process. In step S102, the flow path switching processing unit 83 of the control device 80 performs the filling process. The flow path switching processing unit 83 of the control device 80 drives the advance and retreat motor 26 to advance the second plunger 22 to a predetermined position. In addition, the flow path switching processing unit 83 of the control device 80 detects the position of the second plunger 22 based on the detection value of the encoder 27. The molten resin accumulated in front of the second plunger 22 in the injection cylinder 20 is filled into the cavity space in the mold device via the direction conversion valve 50 and the nozzle 40. In addition, in the filling process, the molten resin supplied from the molten resin supply unit 30 is accumulated in front of the first plunger 12 in the tank cylinder 10 via the molten resin supply unit 30 and the supply discharge valve 70A (tank plunger metering process).

[0109] Fig.14: is a diagram showing the state of the injection device 3A involved in the second embodiment in the pressure holding process. In step S103, the flow path switching processing unit 83 of the control device 80 performs the pressure holding process. In addition, the flow path switching processing unit 83 of the control device 80 controls the advance and retreat motor 26 according to the detection value of the pressure detection unit 28, pushes the second plunger 22 forward, maintains the pressure (holding pressure) of the molten resin in the front end of the second plunger 22 at the set pressure, and pushes the molten resin remaining in the injection cylinder 20 toward the mold device. In addition, in the pressure holding process, the molten resin supplied from the molten resin supply unit 30 is accumulated in front of the first plunger 12 in the tank cylinder 10 via the molten resin supply unit 30 and the supply discharge valve 70A (tank plunger metering process). In addition, the flow path switching processing unit 83 of the control device 80 detects the position of the first plunger 12 according to the detection value of the encoder 17.

[0110] After the pressure holding process is completed, the flow path switching processing unit 83 of the control device 80 rotates the valve core 52 of the direction switching valve 50 before the molding material is supplied from the storage cylinder 10 to the injection cylinder 20 in the next metering process, so that the state of the valve core 52 changes from Fig.14 The second state shown returns to Fig.11 Then, the valve core 72A of the supply and discharge valve 70A is rotated to change the state of the valve core 72A from Fig.14 The first state shown returns to Fig.11 The second state is shown.

[0111] The flow path switching processing unit 83 of the control device 80 repeatedly performs the metering process, the filling process, the pressure holding process, and the like, whereby the injection molding machine 1 repeatedly manufactures molded products.

[0112] In other words, the control device 80 of the injection device 3A according to the second embodiment repeats a tank plunger metering process of supplying molten resin from the molten resin supply unit 30 to the tank cylinder 10 to accumulate molten resin in the tank cylinder 10, a metering process of supplying molten resin from the tank cylinder 10 to the injection cylinder 20 to accumulate molten resin in the injection cylinder 20, a filling process of filling the cavity space in the mold device with molten resin from the injection cylinder 20, and a pressure holding process of maintaining the pressure of the molten resin at a set pressure. In addition, during the injection process (filling process, pressure holding process), the tank plunger metering process of the next molding cycle is performed simultaneously.

[0113] As described above, according to the injection device 3A involved in the second embodiment, it can be used for the injection molding machine system S that continuously supplies molten resin from the molten resin supply device 6 to the molten resin supply part 30, and the molten resin can be accumulated in the tank cylinder 10 in the tank plunger metering process, so that the overflow of the molten resin can be prevented. In addition, in the metering process of supplying the molten resin from the tank cylinder 10 to the injection cylinder 20, the molten resin is discharged from the discharge part 60 to the outside of the injection device 3A. As a result, the overflow of the molten resin in the cylinder body (tank cylinder 10 and / or injection cylinder 20) can be prevented, thereby preventing the damage of the injection device 3.

[0114] <Operation of the Supply and Discharge Valve 70A>

[0115] Next, refer to Figure 8 And use Fig.15 The operation of the supply and discharge valve 70A of the injection device 3A according to the second embodiment will be described. Fig.15 1 is a flowchart showing the operation of the supply and discharge valve 70A in the injection device 3A according to the second embodiment.

[0116] In step S301, the determination unit 81 of the control device 80 determines whether the process of the injection device 3A is in the tank plunger metering process. In other words, it determines whether the supply and discharge valve 70A is in the first state (refer to Figures 12-14 ), and whether the molten resin is being supplied from the molten resin supply unit 30 to the tank cylinder 10. When the tank plunger metering process is not in progress (S301 "No"), the control device 80 repeats the process of step S301. When the tank plunger metering process is in progress (S301 "Yes"), the control device 80 proceeds to step S302.

[0117] In step S302, the determination unit 81 of the control device 80 determines whether the supply stop condition is satisfied. Here, when the supply stop condition is satisfied, the determination unit 81 determines that the cylinder (tank cylinder 10 and / or injection cylinder 20) of the injection device 3A cannot receive the molten resin. The supply stop condition refers to a condition for stopping the supply of the molten resin from the molten resin supply unit 30 to the tank cylinder 10. In other words, it is a condition for discharging the molten resin supplied from the molten resin supply unit 30 from the discharge unit 60. For example, the determination unit 81 of the control device 80 detects the position of the first plunger 12 through the encoder 17, and when the first plunger 12 retreats to a predetermined position (for example, a retreat limit), it determines that the supply stop condition is satisfied. In addition, when the cycle time exceeds the predetermined time, the determination unit 81 of the control device 80 may also determine that the supply stop condition is satisfied. In addition, the determination unit 81 of the control device 80 may also determine whether the supply stop condition is satisfied based on the detection value of the pressure detection unit 18. When the supply stop condition is not satisfied (S302: No), the control device 80 returns the process to step S301. When the supply stop condition is satisfied (S302: Yes), the control device 80 proceeds to step S303.

[0118] Fig.16 3A is a diagram showing the state of the injection device 3A according to the second embodiment when the supply and discharge valve 70A is in the second state. In step S303, the processing unit 82 of the control device 80 controls the valve core driving unit of the supply and discharge valve 70A to put the valve core 72A of the supply and discharge valve 70A in the second state. The molten resin supplied from the molten resin supply unit 30 is discharged from the discharge unit 60 to the outside of the injection device 3A via the molten resin supply unit 30 and the supply and discharge valve 70A.

[0119] In step S304, the determination unit 81 of the control device 80 determines whether the operation of the injection device 3A starts the tank plunger metering process. In other words, it is determined whether the metering process S101 of supplying molten resin from the tank cylinder 10 to the injection cylinder 20 is completed and the molten resin supply unit 30 can supply molten resin to the tank cylinder 10. When the tank plunger metering process has not started (S304 "No"), the processing of the control device 80 returns to step S303. When the tank plunger metering process starts (S304 "Yes"), the processing of the control device 80 goes to step S305.

[0120] In step S305, the processing unit 82 of the control device 80 controls the valve element driving unit of the supply and discharge valve 70A so that the valve element 72A of the supply and discharge valve 70A is in the first state (see Fig.12 ). Then, the processing of the control device 80 returns to step S301.

[0121] Thus, according to the injection device 3A involved in the second embodiment, when it is determined that the cylinder body (tank cylinder 10 and / or injection cylinder 20) of the injection device 3A cannot receive the molten resin, the molten resin supplied from the molten resin supply unit 30 is discharged to the outside of the injection device 3A from the discharge unit 60. Thus, the overflow of the molten resin in the cylinder body (tank cylinder 10 and / or injection cylinder 20) can be prevented, and the damage of the injection device 3 can be prevented.

[0122] The above describes the embodiments of the injection molding machine system S, the injection molding machine 1, and the injection devices 3 and 3A. However, the present invention is not limited to the above embodiments, and various modifications and improvements can be made within the scope of the gist of the present invention described in the technical solution.

[0123] The direction switching valve 50 is described as a switching valve that switches the flow direction by rotating the valve core 52 in the valve body 51, but it is not limited to this. The direction switching valve 50 can be a switching valve that switches the flow direction by sliding the valve core in the valve body, or it can be a switching valve that switches the flow direction by other structures. Furthermore, the discharge valve 70 is described as a switching valve that switches the flow direction by rotating the valve core 72 in the valve body 71, but it is not limited to this. The discharge valve 70 can be a switching valve that switches the flow direction by sliding the valve core in the valve body, or it can be a switching valve that switches the flow direction by other structures.

[0124] The discharge valve 70 is described as a direction switching valve, but the invention is not limited thereto. For example, the discharge valve 70 may be configured as an on-off valve provided in the discharge portion 60. In this configuration, the control device 80 switches the on-off valve serving as the discharge valve 70 to a closed valve state (a first state) and an open valve state (a second state) instead of switching the direction switching valve serving as the discharge valve 70 to the first state and the second state.

[0125] Furthermore, the discharge valve 70 may be configured as a safety valve that opens when the pressure of the molten resin in the tank cylinder 10 becomes equal to or higher than a predetermined pressure.

[0126] Furthermore, the judgment unit 81 of the control device 80 (4) may also be configured to close the control valve 8 (refer to the control valve 81 of the molten resin supply passage 7) when the supply stop condition is satisfied (S202 "Yes" / S302 "Yes"), in other words, when it is determined that the cylinder body (tank cylinder 10 and / or injection cylinder 20) of the injection device 3, 3A cannot receive the molten resin. Figure 1 ), instead of switching the direction change valve as the discharge valve 70 to the first state and the second state. Thereby, the supply of the molten resin to the injection device 3 can be cut off.

[0127] Furthermore, the judgment unit 81 of the control device 80 (4) may be configured such that when the supply stop condition is satisfied (S202 "Yes" / S302 "Yes"), in other words, when it is determined that the cylinder (tank cylinder 10 and / or injection cylinder 20) of the injection device 3, 3A cannot receive the molten resin, a signal indicating the situation is sent to a higher-level management device (not shown) that controls the entire injection molding machine system S. The higher-level management device that has received the signal can cut off the supply of the molten resin to the injection device 3 by controlling (closing) the control valve 8 that controls the entire injection molding machine system S, for example, the molten resin supply device 6.

[0128] The injection device 3, 3A is described as supplying only molten resin, but it is not limited to this. For example, it is also possible to have a structure in which molten resin and particles are supplied to the first cylinder. In this case, a screw may be provided in the first cylinder instead of the first plunger. In addition, the first plunger drive unit 15 may also include a screw rotation motor that rotates the screw and a screw advance and retreat motor that rotates the screw in the first cylinder.

[0129] Although the injection device 3 or 3A is described as having two cylinders (tank cylinder 10 and injection cylinder 20), the present invention is not limited thereto. For example, the injection device 3 or 3A may be configured to have one cylinder or may be configured to have three or more cylinders.

Claims

1. An injection molding machine, comprising: an injection device supplied with molten resin; and a control device for controlling the injection device, The control device has: a determination unit that determines whether the molten resin can be supplied to the injection device; and a processing unit that processes the supply of the molten resin according to the determination result of the determination unit; The injection device comprises: a first cylinder, a first directional switching valve, a first connection port connecting the first cylinder and the first directional switching valve, a second cylinder, a second directional switching valve, a second connection port connecting the second cylinder and the second directional switching valve, a molten resin supplying portion, a connecting portion connecting the first directional switching valve and the second directional switching valve, a discharging portion discharging the molten resin supplied to the injection device, and a nozzle injecting the molten resin supplied to the second cylinder into a mold device; The injection device accumulates resin in the first cylinder through the first connection port, and extrude the resin in the first cylinder toward the connection portion through the first connection port; accumulates resin in the second cylinder through the second connection port, and extrude the resin in the second cylinder toward the nozzle through the second connection port; The first directional switching valve switches the connection and disconnection between the molten resin supply unit, the first connection port, the connection unit, and the discharge unit; The second directional switching valve switches the connection and disconnection of the connection portion, the second connection port, and the nozzle; When the first directional switching valve is in a first state, the molten resin supply portion is connected to the first connection port, and the discharge portion is connected to the connection portion; when the first directional switching valve is in a second state, the molten resin supply portion is connected to the discharge portion, and the first connection port is connected to the connection portion; In the first state, molten resin can be supplied from the molten resin supply part to the first cylinder and molten resin can be discharged from the second cylinder to the discharge part, while the discharge part and the connection part are blocked from communication with the molten resin supply part and the first connection port.

2. The injection molding machine according to claim 1, wherein: The processing unit performs the following processing: If the determination unit determines that the injection device cannot supply the molten resin to the first cylinder, the molten resin supplied from the molten resin supply unit is discharged from the discharge unit.

3. The injection molding machine according to claim 2, wherein: The injection device comprises: a discharge passage for discharging the molten resin from the molten resin supply portion to the discharge portion; The processing unit performs the following processing: If the determination unit determines that the injection device can supply molten resin to the first cylinder, the first directional switching valve is controlled to cut off the discharge passage; If the determination unit determines that the injection device cannot supply the molten resin to the first cylinder, the first directional switching valve is controlled to communicate with the discharge passage.

4. The injection molding machine according to claim 2, wherein: The injection device comprises: a supply passage for supplying molten resin from a molten resin supply portion to the first cylinder; and a discharge passage for discharging the molten resin from the molten resin supply portion to the discharge portion; The processing unit performs the following processing: If the determination unit determines that the injection device can supply molten resin to the first cylinder, the first directional switching valve is controlled to connect the supply passage and cut off the discharge passage; If the determination unit determines that the injection device cannot supply the molten resin to the first cylinder, the first directional control valve is controlled to connect the discharge passage and block the supply passage.

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