Injection molding system, injection molding machine

Abstract

This disclosure provides an injection molding system that can open and close a solenoid valve even when the pressure of a temperature-controlled medium supplied via the solenoid valve increases. [Solution] The injection molding system SYS comprises a plurality of injection molding machines 10 connected in series to a supply passage SL for a temperature-controlled medium TM. Each injection molding machine 10 has a temperature-controlled passage 317 through which the temperature-controlled medium TM passes, and a solenoid valve 315 that opens and closes the temperature-controlled passage 317. The plurality of injection molding machines 10 include an upstream molding machine 10U connected to the upstream part US of the supply passage SL, and a downstream molding machine 10D connected to the downstream part DS of the supply passage SL where the pressure of the temperature-controlled medium TM is lower than that of the upstream part US. The opening and closing force of the solenoid valve 315 of the upstream molding machine 10U is greater than the opening and closing force of the solenoid valve 315 of the downstream molding machine 10D.

Description

Technical Field

[0001] The present disclosure relates to an injection molding system and an injection molding machine.

Background Art

[0002] Conventionally, a molding apparatus including a mold with a temperature control mechanism and a resin filling device has been known (for example, see Patent Document 1 below). The mold consists of a first mold and a second mold. When the mold is clamped, a cavity, which is a molding space, is formed in the mold.

[0003] The first mold has a plurality of heaters constituting a temperature control mechanism, and the second mold also has a plurality of heaters constituting a temperature control mechanism. Further, the first mold has two systems of cooling water flow paths constituting a temperature control mechanism, and the second mold has one system of cooling water flow paths constituting a temperature control mechanism.

[0004] On each of the respective flow paths connected to the upstream side of each cooling water flow path, a cooling water pump and a solenoid valve are installed. Each cooling water pump is constantly driven to supply cooling water to each cooling water flow path. Each solenoid valve is disposed downstream of the cooling water pump in the flow path and is configured to switch each cooling water flow path between an open state and a closed state. When the solenoid valve is switched to the open state, it enables the supply of cooling water to the cooling water flow path.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] When multiple injection molding machines, each having a temperature-controlled channel through which a temperature-controlled medium passes and a solenoid valve for opening and closing the temperature-controlled channel, are connected in series to a supply path for the temperature-controlled medium, an increase in the pressure of the temperature-controlled medium flowing through the channel may cause problems with the opening and closing of the solenoid valve.

[0007] This disclosure provides an injection molding system and injection molding machine capable of opening and closing a solenoid valve even when the pressure of the temperature-controlled medium supplied via the solenoid valve increases. [Means for solving the problem]

[0008] One aspect of the present disclosure provides an injection molding system comprising a plurality of injection molding machines, each having a temperature-controlled channel for passing a temperature-controlled medium and a solenoid valve for opening and closing the temperature-controlled channel, wherein the plurality of injection molding machines are connected in series to a supply path for the temperature-controlled medium, and the plurality of injection molding machines include an upstream molding machine connected to the upstream part of the supply path and a downstream molding machine connected to the downstream part of the supply path where the pressure of the temperature-controlled medium is lower than that of the upstream part, wherein the opening and closing force of the solenoid valve of the upstream molding machine is greater than the opening and closing force of the solenoid valve of the downstream molding machine.

[0009] Another aspect of the present disclosure provides an injection molding machine comprising: an injection device for melting and injecting a molding material; a temperature control channel provided in the injection device; a solenoid valve capable of opening and closing the temperature control channel; a power supply capable of supplying current to the solenoid valve; and a power amplifier detachably mounted at a position where it can be connected to the solenoid valve and the power supply, and capable of amplifying the current and supplying it to the solenoid valve. [Effects of the Invention]

[0010] According to each of the above embodiments of this disclosure, an injection molding system and injection molding machine can be provided that can open and close a solenoid valve even when the pressure of the temperature-controlled medium supplied via the solenoid valve increases. [Brief explanation of the drawing]

[0011] [Figure 1] This diagram shows the state of the injection molding machine when the mold opening is complete. [Figure 2]This diagram shows the state of the injection molding machine during mold clamping. [Figure 3] This is a cross-sectional view showing an example of an injection device. [Figure 4] This is a circuit diagram showing the path of the temperature-controlled medium in an injection molding system. [Figure 5] This is a schematic diagram showing an example of the configuration of a solenoid valve in an injection molding machine. [Figure 6] Figure 5 is a block diagram showing an example of solenoid valve control. [Figure 7] This is a schematic diagram showing an example of the configuration of a solenoid valve in an injection molding machine. [Figure 8] This is a schematic diagram showing an example of the configuration of a solenoid valve in an injection molding machine. [Figure 9] This is a block diagram showing an example of solenoid valve control in Figure 7 or Figure 8. [Modes for carrying out the invention]

[0012] Embodiments of the nozzle according to this disclosure will be described below with reference to the drawings. The embodiments described below are illustrative and do not limit the invention. Not all features and combinations thereof in the embodiments of this disclosure are necessarily essential to the invention. In addition, the same or corresponding components in each drawing are denoted by the same or corresponding reference numerals, and redundant descriptions may be omitted.

[0013] (injection molding machine) Figure 1 shows the state of an injection molding machine when the mold opening is complete according to one embodiment of this disclosure. Figure 2 shows the state of the injection molding machine when the mold is clamped according to the embodiment of Figure 1. In this specification, the X-axis direction, Y-axis direction, and Z-axis direction are perpendicular to each other. The X-axis direction and Y-axis direction represent the horizontal direction, and the Z-axis direction represents the vertical direction. When the mold clamping device 100 is horizontal, the X-axis direction is the mold opening and closing direction, and the Y-axis direction is the width direction of the injection molding machine 10. The negative side in the Y-axis direction is called the operating side, and the positive side in the Y-axis direction is called the non-operating side.

[0014] As shown in FIGS. 1 and 2, the injection molding machine 10 includes a mold clamping device 100 for opening and closing the mold device 800, an ejector device 200 for ejecting the molded product formed by the mold device 800, an injection device 300 for injecting a molding material into the mold device 800, a moving device 400 for moving the injection device 300 forward and backward with respect to the mold device 800, a control device 700 for controlling each component of the injection molding machine 10, and a frame 900 for supporting each component of the injection molding machine 10. The frame 900 includes a mold clamping device frame 910 for supporting the mold clamping device 100 and an injection device frame 920 for supporting the injection device 300. The mold clamping device frame 910 and the injection device frame 920 are each installed on the floor 2 via a leveling adjuster 930. The control device 700 is arranged in the internal space of the injection device frame 920. Hereinafter, each component of the injection molding machine 10 will be described.

[0015] (Mold clamping device) In the description of the mold clamping device 100, the moving direction of the movable platen 120 at the time of mold closing (for example, the positive direction of the X-axis) is described as the front, and the moving direction of the movable platen 120 at the time of mold opening (for example, the negative direction of the X-axis) is described as the rear.

[0016] The mold clamping device 100 performs mold closing, pressure boosting, mold clamping, pressure release, and mold opening of the mold device 800. The mold device 800 includes a fixed mold 810 and a movable mold 820.

[0017] The mold clamping device 100 is, for example, a horizontal type, and the mold opening and closing direction is a horizontal direction. The mold clamping device 100 includes a fixed platen 110 to which the fixed mold 810 is attached, a movable platen 120 to which the movable mold 820 is attached, and a moving mechanism 102 for moving the movable platen 120 in the mold opening and closing direction with respect to the fixed platen 110.

[0018] The fixed platen 110 is fixed to the mold clamping device frame 910. The fixed mold 810 is attached to the opposing surface of the fixed platen 110 with respect to the movable platen 120.

[0019] The movable platen 120 is positioned to move freely in the mold opening and closing direction relative to the mold clamping device frame 910. Guides 101 are laid on the mold clamping device frame 910 to guide the movable platen 120. A movable mold 820 is attached to the surface of the movable platen 120 facing the fixed platen 110.

[0020] The moving mechanism 102 performs mold closing, pressure increasing, mold clamping, depressurization, and mold opening of the mold device 800 by moving the movable platen 120 forward and backward relative to the fixed platen 110. The moving mechanism 102 includes a toggle support 130 positioned at a distance from the fixed platen 110, a tie bar 140 connecting the fixed platen 110 and the toggle support 130, a toggle mechanism 150 that moves the movable platen 120 in the mold opening and closing direction relative to the toggle support 130, a mold clamping motor 160 that operates the toggle mechanism 150, a motion conversion mechanism 170 that converts the rotational motion of the mold clamping motor 160 into linear motion, and a mold thickness adjustment mechanism 180 that adjusts the distance between the fixed platen 110 and the toggle support 130.

[0021] The toggle support 130 is positioned at a distance from the fixed platen 110 and is mounted on the mold clamping device frame 910 so as to be movable in the mold opening and closing direction. The toggle support 130 may also be positioned so as to be movable along a guide laid on the mold clamping device frame 910. The guide for the toggle support 130 may be the same as the guide 101 for the movable platen 120.

[0022] In this embodiment, the fixed platen 110 is fixed to the clamping device frame 910, and the toggle support 130 is arranged to be movable relative to the clamping device frame 910 in the mold opening and closing direction. Alternatively, the toggle support 130 may be fixed to the clamping device frame 910, and the fixed platen 110 may be arranged to be movable relative to the clamping device frame 910 in the mold opening and closing direction.

[0023] The tie bars 140 connect the fixed platen 110 and the toggle support 130 at a distance L in the mold opening and closing direction. Multiple tie bars 140 (for example, four) may be used. Multiple tie bars 140 are arranged parallel to the mold opening and closing direction and stretch in accordance with the clamping force. At least one tie bar 140 may be provided with a tie bar strain detector 141 that detects the strain of the tie bar 140. The tie bar strain detector 141 sends a signal indicating its detection result to the control device 700. The detection result of the tie bar strain detector 141 is used for detecting the clamping force, etc.

[0024] In this embodiment, a tie bar strain detector 141 is used as a clamping force detector to detect the clamping force, but the present invention is not limited to this. The clamping force detector is not limited to strain gauge type, but may be piezoelectric, capacitive, hydraulic, electromagnetic, etc., and its mounting position is not limited to the tie bar 140.

[0025] The toggle mechanism 150 is positioned between the movable platen 120 and the toggle support 130, and moves the movable platen 120 in the mold opening and closing direction relative to the toggle support 130. The toggle mechanism 150 has a crosshead 151 that moves in the mold opening and closing direction, and a pair of link groups that bend and extend as the crosshead 151 moves. Each of the pair of link groups has a first link 152 and a second link 153 that are bendable and extendable connected by a pin or the like. The first link 152 is pivotably attached to the movable platen 120 by a pin or the like. The second link 153 is pivotably attached to the toggle support 130 by a pin or the like. The second link 153 is attached to the crosshead 151 via a third link 154. When the crosshead 151 moves forward and backward relative to the toggle support 130, the first link 152 and the second link 153 bend and extend, and the movable platen 120 moves forward and backward relative to the toggle support 130.

[0026] Furthermore, the configuration of the toggle mechanism 150 is not limited to the configuration shown in Figures 1 and 2. For example, in Figures 1 and 2, each link group has five nodes, but it may also have four, and one end of the third link 154 may be connected to the node between the first link 152 and the second link 153.

[0027] The clamping motor 160 is attached to the toggle support 130 and operates the toggle mechanism 150. The clamping motor 160 moves the crosshead 151 forward and backward relative to the toggle support 130, thereby bending and extending the first link 152 and the second link 153, and moving the movable platen 120 forward and backward relative to the toggle support 130. The clamping motor 160 is directly connected to the motion conversion mechanism 170, but it may also be connected to the motion conversion mechanism 170 via a belt, pulley, or the like.

[0028] The motion conversion mechanism 170 converts the rotational motion of the clamping motor 160 into the linear motion of the crosshead 151. The motion conversion mechanism 170 includes a screw shaft and a screw nut that screws onto the screw shaft. A ball or roller may be interposed between the screw shaft and the screw nut.

[0029] The mold clamping device 100 performs processes such as mold closing, pressure boosting, mold clamping, depressurization, and mold opening under the control of the control device 700.

[0030] In the mold closing process, the clamping motor 160 is driven to advance the crosshead 151 to the mold closing completion position at a set movement speed, thereby advancing the movable platen 120 and bringing the movable mold 820 into contact with the fixed mold 810. The position and movement speed of the crosshead 151 are detected using, for example, a clamping motor encoder 161. The clamping motor encoder 161 detects the rotation of the clamping motor 160 and sends a signal indicating the detection result to the control device 700.

[0031] Furthermore, the crosshead position detector for detecting the position of the crosshead 151 and the crosshead speed detector for detecting the movement speed of the crosshead 151 are not limited to the clamping motor encoder 161, and general-purpose devices can be used. Similarly, the movable platen position detector for detecting the position of the movable platen 120 and the movable platen speed detector for detecting the movement speed of the movable platen 120 are not limited to the clamping motor encoder 161, and general-purpose devices can be used.

[0032] In the boosting process, the clamping motor 160 is further driven to advance the crosshead 151 from the closed position to the clamping position, thereby generating clamping force.

[0033] In the clamping process, the clamping motor 160 is driven to maintain the position of the crosshead 151 in the clamping position. In the clamping process, the clamping force generated in the pressurization process is maintained. In the clamping process, a cavity space 801 (see Figure 2) is formed between the movable mold 820 and the fixed mold 810, and the injection unit 300 fills the cavity space 801 with liquid molding material. A molded product is obtained when the filled molding material solidifies.

[0034] The number of cavity spaces 801 may be one or more. In the latter case, multiple molded products can be obtained simultaneously. An insert material may be placed in a portion of the cavity space 801, and the molding material may be filled in the other portion of the cavity space 801. This results in a molded product in which the insert material and the molding material are integrated.

[0035] In the depressurization process, the clamping motor 160 is driven to retract the crosshead 151 from the clamping position to the mold opening start position, thereby retracting the movable platen 120 and reducing the clamping force. The mold opening start position and the mold closing completion position may be the same position.

[0036] In the mold opening process, the clamping motor 160 is driven to retract the crosshead 151 from the mold opening start position to the mold opening completion position at a set movement speed, thereby retracting the movable platen 120 and separating the movable mold 820 from the fixed mold 810. Subsequently, the ejector device 200 ejects the molded product from the movable mold 820.

[0037] The setting conditions for the mold closing process, the pressure boosting process, and the mold clamping process are set together as a series of setting conditions. For example, the movement speed and position of the crosshead 151 (including the mold closing start position, movement speed switching position, mold closing completion position, and mold clamping position), and the mold clamping force in the mold closing process and the pressure boosting process are set together as a series of setting conditions. The mold closing start position, movement speed switching position, mold closing completion position, and mold clamping position are arranged in this order from rear to front and represent the start and end points of the section in which the movement speed is set. The movement speed is set for each section. There may be one or more movement speed switching positions. There may be no movement speed switching positions. The mold clamping position and the mold clamping force may be set individually or individually.

[0038] The setting conditions for the depressurization process and the mold opening process are set similarly. For example, the movement speed and position of the crosshead 151 in the depressurization process and the mold opening process (mold opening start position, movement speed switching position, and mold opening completion position) are set together as a series of setting conditions. The mold opening start position, movement speed switching position, and mold opening completion position are arranged in this order from front to back and represent the start and end points of the sections in which the movement speed is set. The movement speed is set for each section. There may be one or more movement speed switching positions. There may be no movement speed switching positions. The mold opening start position and the mold closing completion position may be the same position. Also, the mold opening completion position and the mold closing start position may be the same position.

[0039] Furthermore, instead of the movement speed and position of the crosshead 151, the movement speed and position of the movable platen 120 may be set. Also, instead of the position of the crosshead (e.g., the clamping position) or the position of the movable platen, the clamping force may be set.

[0040] Incidentally, the toggle mechanism 150 amplifies the driving force of the clamping motor 160 and transmits it to the movable platen 120. This amplification ratio is also called the toggle ratio. The toggle ratio changes according to the angle θ between the first link 152 and the second link 153 (hereinafter also referred to as the "link angle θ"). The link angle θ can be determined from the position of the crosshead 151. The toggle ratio is maximized when the link angle θ is 180°.

[0041] If the thickness of the mold device 800 changes due to replacement of the mold device 800 or a change in the temperature of the mold device 800, the mold thickness is adjusted so that a predetermined clamping force is obtained during mold clamping. In mold thickness adjustment, for example, the distance L between the fixed platen 110 and the toggle support 130 is adjusted so that the link angle θ of the toggle mechanism 150 becomes a predetermined angle at the time of mold touch when the movable mold 820 touches the fixed mold 810.

[0042] The mold clamping device 100 has a mold thickness adjustment mechanism 180. The mold thickness adjustment mechanism 180 adjusts the mold thickness by adjusting the distance L between the fixed platen 110 and the toggle support 130. The timing of the mold thickness adjustment is, for example, between the end of one molding cycle and the start of the next molding cycle. The mold thickness adjustment mechanism 180 includes, for example, a screw shaft 181 formed at the rear end of the tie bar 140, a screw nut 182 that is rotatably and immovably held by the toggle support 130, and a mold thickness adjustment motor 183 that rotates the screw nut 182 that is screwed onto the screw shaft 181.

[0043] A screw shaft 181 and screw nut 182 are provided for each tie bar 140. The rotational driving force of the mold thickness adjustment motor 183 may be transmitted to multiple screw nuts 182 via a rotational driving force transmission unit 185. Multiple screw nuts 182 can be rotated synchronously. It is also possible to rotate multiple screw nuts 182 individually by changing the transmission path of the rotational driving force transmission unit 185.

[0044] The rotational drive force transmission unit 185 is composed of, for example, gears. In this case, driven gears are formed on the outer circumference of each screw nut 182, and a drive gear is attached to the output shaft of the mold thickness adjustment motor 183. In addition, an intermediate gear that meshes with multiple driven gears and a drive gear is rotatably held in the center of the toggle support 130. Note that the rotational drive force transmission unit 185 may be composed of belts, pulleys, or the like instead of gears.

[0045] The operation of the mold thickness adjustment mechanism 180 is controlled by the control device 700. The control device 700 drives the mold thickness adjustment motor 183 to rotate the screw nut 182. As a result, the position of the toggle support 130 relative to the tie bar 140 is adjusted, and the distance L between the fixed platen 110 and the toggle support 130 is adjusted. Multiple mold thickness adjustment mechanisms may be used in combination.

[0046] The interval L is detected using the mold thickness adjustment motor encoder 184. The mold thickness adjustment motor encoder 184 detects the amount and direction of rotation of the mold thickness adjustment motor 183 and sends a signal indicating the detection result to the control device 700. The detection result of the mold thickness adjustment motor encoder 184 is used to monitor and control the position and interval L of the toggle support 130. Note that the toggle support position detector for detecting the position of the toggle support 130 and the interval detector for detecting the interval L are not limited to the mold thickness adjustment motor encoder 184, but general-purpose devices can be used.

[0047] The clamping device 100 may have a mold temperature controller that adjusts the temperature of the mold device 800. The mold device 800 has a flow path for a temperature-controlled medium inside it. The mold temperature controller adjusts the temperature of the mold device 800 by adjusting the temperature of the temperature-controlled medium supplied to the flow path of the mold device 800.

[0048] In this embodiment, the mold clamping device 100 is a horizontal type in which the mold opening and closing direction is horizontal, but it may also be a vertical type in which the mold opening and closing direction is vertical.

[0049] Furthermore, although the clamping device 100 of this embodiment has a clamping motor 160 as a drive unit, it may have a hydraulic cylinder instead of the clamping motor 160. Also, the clamping device 100 may have a linear motor for opening and closing the mold and an electromagnet for clamping the mold.

[0050] (Ejector device) In describing the ejector device 200, similar to the description of the clamping device 100, the direction of movement of the movable platen 120 when the mold is closed (for example, the positive X-axis direction) is described as forward, and the direction of movement of the movable platen 120 when the mold is open (for example, the negative X-axis direction) is described as backward.

[0051] The ejector device 200 is attached to the movable platen 120 and moves back and forth together with the movable platen 120. The ejector device 200 includes an ejector rod 210 that ejects the molded product from the mold device 800 and a drive mechanism 220 that moves the ejector rod 210 in the direction of movement of the movable platen 120 (in the X-axis direction).

[0052] The ejector rod 210 is positioned to move back and forth within a through-hole in the movable platen 120. The front end of the ejector rod 210 contacts the ejector plate 826 of the movable mold 820. The front end of the ejector rod 210 may or may not be connected to the ejector plate 826.

[0053] The drive mechanism 220 includes, for example, an ejector motor and a motion conversion mechanism that converts the rotational motion of the ejector motor into the linear motion of the ejector rod 210. The motion conversion mechanism includes a screw shaft and a screw nut that screws onto the screw shaft. A ball or roller may be interposed between the screw shaft and the screw nut.

[0054] The ejector device 200 performs the ejection process under the control of the control device 700. In the ejection process, the ejector rod 210 is advanced from the standby position to the ejection position at a set travel speed, thereby advancing the ejector plate 826 and ejecting the molded product. Subsequently, the ejector motor is driven to retract the ejector rod 210 at a set travel speed, retracting the ejector plate 826 back to its original standby position.

[0055] The position and speed of the ejector rod 210 are detected, for example, using an ejector motor encoder. The ejector motor encoder detects the rotation of the ejector motor and sends a signal indicating the detection result to the control device 700. Note that the ejector rod position detector, which detects the position of the ejector rod 210, and the ejector rod speed detector, which detects the speed of the ejector rod 210, are not limited to ejector motor encoders, but general-purpose devices can be used.

[0056] (injection device) In the description of the injection device 300, unlike the descriptions of the clamping device 100 and the ejector device 200, the direction of movement of the screw 330 during filling (for example, the negative X-axis direction) is described as forward, and the direction of movement of the screw 330 during metering (for example, the positive X-axis direction) is described as backward.

[0057] The injection device 300 is mounted on a slide base 301, which is positioned to move back and forth relative to the injection device frame 920. The injection device 300 is positioned to move back and forth relative to the mold device 800. The injection device 300 touches the mold device 800 and fills the cavity space 801 within the mold device 800 with molding material. The injection device 300 includes, for example, a cylinder 310 for heating the molding material, a nozzle 320 provided at the front end of the cylinder 310, a screw 330 positioned within the cylinder 310 to move back and forth and to rotate, a metering motor 340 for rotating the screw 330, an injection motor 350 for moving the screw 330 back and forth, and a load detector 360 for detecting the load transmitted between the injection motor 350 and the screw 330.

[0058] Cylinder 310 heats the molding material supplied to its interior from the supply port 311. The molding material includes, for example, resin. The molding material is formed, for example, into pellets and supplied to the supply port 311 in a solid state. The supply port 311 is formed at the rear of cylinder 310. A cooler 312, such as a water-cooled cylinder, is provided on the outer circumference of the rear of cylinder 310. In front of the cooler 312, a first heater 313, such as a band heater, and a first temperature detector 314 are provided on the outer circumference of cylinder 310.

[0059] The cylinder 310 is divided into multiple zones along its axial direction (for example, the X-axis direction). A first heater 313 and a first temperature detector 314 are provided in each of the multiple zones. A set temperature is set for each of the multiple zones, and the control device 700 controls the first heater 313 so that the temperature detected by the first temperature detector 314 becomes the set temperature.

[0060] The nozzle 320 is located at the front end of the cylinder 310 and is pressed against the mold device 800. A second heater 323 and a second temperature detector 324 are provided on the outer circumference of the nozzle 320. The control device 700 controls the second heater 323 so that the temperature detected by the second temperature detector 324 becomes the set temperature.

[0061] The screw 330 is rotatably and reciprocally positioned within the cylinder 310. When the screw 330 is rotated, the molding material is fed forward along the helical groove of the screw 330. As the molding material is fed forward, it is gradually melted by the heat from the cylinder 310. As the liquid molding material is fed forward to the front of the screw 330 and accumulates at the front of the cylinder 310, the screw 330 is retracted. Then, when the screw 330 is advanced, the liquid molding material accumulated in front of the screw 330 is injected from the nozzle 320 and filled into the mold device 800.

[0062] A backflow prevention ring 331 is mounted on the front of the screw 330 so as to be movable back and forth, acting as a backflow prevention valve to prevent backflow of the molding material from the front to the rear of the screw 330 when the screw 330 is pushed forward.

[0063] When the screw 330 is advanced, the backflow prevention ring 331 is pushed backward by the pressure of the molding material in front of the screw 330, and retracts relative to the screw 330 to a closed position (see Figure 2) that blocks the flow path of the molding material. This prevents the molding material accumulated in front of the screw 330 from flowing backward.

[0064] On the other hand, when the screw 330 is rotated, the backflow prevention ring 331 is pushed forward by the pressure of the molding material being sent forward along the helical groove of the screw 330, and moves relative to the screw 330 to an open position (see Figure 1) that opens the flow path of the molding material. As a result, the molding material is sent forward of the screw 330.

[0065] The backflow prevention ring 331 may be either a co-rotating type that rotates together with the screw 330, or a non-co-rotating type that does not rotate together with the screw 330.

[0066] Furthermore, the injection device 300 may have a drive source that moves the backflow prevention ring 331 back and forth between an open position and a closed position relative to the screw 330.

[0067] The metering motor 340 rotates the screw 330. The drive source for rotating the screw 330 is not limited to the metering motor 340; for example, a hydraulic pump or the like may also be used.

[0068] The injection motor 350 moves the screw 330 forward and backward. Between the injection motor 350 and the screw 330, there is a motion conversion mechanism that converts the rotational motion of the injection motor 350 into the linear motion of the screw 330. The motion conversion mechanism has, for example, a screw shaft and a screw nut that screws onto the screw shaft. Balls or rollers may be provided between the screw shaft and the screw nut. The drive source for moving the screw 330 forward and backward is not limited to the injection motor 350, but may also be, for example, a hydraulic cylinder.

[0069] The load detector 360 detects the load transmitted between the injection motor 350 and the screw 330. The detected load is converted into pressure by the control device 700. The load detector 360 is installed in the load transmission path between the injection motor 350 and the screw 330 and detects the load acting on the load detector 360.

[0070] The load detector 360 sends a signal of the detected load to the control device 700. The load detected by the load detector 360 is converted into pressure acting between the screw 330 and the molding material and used for controlling and monitoring the pressure the screw 330 receives from the molding material, the back pressure on the screw 330, and the pressure acting from the screw 330 on the molding material.

[0071] Furthermore, the pressure detector used to detect the pressure of the molding material is not limited to the load detector 360, but a general-purpose one can be used. For example, a nozzle pressure sensor or an in-mold pressure sensor may be used. The nozzle pressure sensor is installed in the nozzle 320. The in-mold pressure sensor is installed inside the mold device 800.

[0072] The injection device 300 performs processes such as metering, filling, and holding pressure under the control of the control device 700. The filling and holding pressure processes may be collectively referred to as the injection process.

[0073] In the metering process, the metering motor 340 is driven to rotate the screw 330 at a set rotational speed, and the molding material is fed forward along the helical groove of the screw 330. As this occurs, the molding material is gradually melted. As the liquid molding material is fed forward by the screw 330 and accumulates at the front of the cylinder 310, the screw 330 is retracted. The rotational speed of the screw 330 is detected, for example, using a metering motor encoder 341. The metering motor encoder 341 detects the rotation of the metering motor 340 and sends a signal indicating the detection result to the control device 700. Note that the screw rotational speed detector for detecting the rotational speed of the screw 330 is not limited to the metering motor encoder 341, and a general-purpose one can be used.

[0074] In the weighing process, the injection motor 350 may be driven to apply a set back pressure to the screw 330 in order to limit the rapid retraction of the screw 330. The back pressure on the screw 330 is detected, for example, using a load detector 360. The weighing process is completed when the screw 330 has retracted to the weighing completion position and a predetermined amount of molding material has accumulated in front of the screw 330.

[0075] The position and rotational speed of the screw 330 in the metering process are set together as a series of setting conditions. For example, the metering start position, rotational speed switching position, and metering completion position are set. These positions are arranged in this order from front to back and represent the start and end points of the sections in which the rotational speed is set. The rotational speed is set for each section. There may be one or more rotational speed switching positions. The rotational speed switching positions may not be set. In addition, back pressure is set for each section.

[0076] In the filling process, the injection motor 350 is driven to advance the screw 330 at a set speed, filling the cavity space 801 in the mold device 800 with the liquid molding material accumulated in front of the screw 330. The position and speed of the screw 330 are detected, for example, using an injection motor encoder 351. The injection motor encoder 351 detects the rotation of the injection motor 350 and sends a signal indicating the detection result to the control device 700. When the position of the screw 330 reaches the set position, a switchover from the filling process to the holding pressure process (so-called V / P switching) occurs. The position at which the V / P switching occurs is also called the V / P switching position. The set speed of the screw 330 may be changed depending on the position and time of the screw 330.

[0077] The position and movement speed of the screw 330 during the filling process are set together as a series of setting conditions. For example, the filling start position (also called the "injection start position"), the movement speed switching position, and the V / P switching position are set. These positions are arranged in this order from rear to front and represent the start and end points of the sections in which the movement speed is set. The movement speed is set for each section. There may be one or more movement speed switching positions. The movement speed switching positions do not need to be set.

[0078] For each section in which the movement speed of the screw 330 is set, an upper limit is set for the pressure of the screw 330. The pressure of the screw 330 is detected by the load sensor 360. If the pressure of the screw 330 is below the set pressure, the screw 330 moves forward at the set movement speed. On the other hand, if the pressure of the screw 330 exceeds the set pressure, for the purpose of protecting the mold, the screw 330 moves forward at a slower movement speed than the set movement speed so that the pressure of the screw 330 becomes below the set pressure.

[0079] Furthermore, during the filling process, after the screw 330 reaches the V / P switching position, the screw 330 may be temporarily stopped at the V / P switching position, and then the V / P switching may be performed. Immediately before the V / P switching, instead of stopping the screw 330, the screw 330 may be moved forward or backward at a slow speed. In addition, the screw position detector that detects the position of the screw 330 and the screw movement speed detector that detects the movement speed of the screw 330 are not limited to the injection motor encoder 351, but general-purpose ones can be used.

[0080] In the holding pressure process, the injection motor 350 is driven to push the screw 330 forward, maintaining the pressure of the molding material at the front end of the screw 330 (hereinafter also referred to as "holding pressure") at a set pressure, and pushing the molding material remaining in the cylinder 310 toward the mold device 800. This allows for the replenishment of molding material that has been lost due to cooling shrinkage within the mold device 800. The holding pressure is detected, for example, using a load detector 360. The set value of the holding pressure may be changed according to the elapsed time from the start of the holding pressure process. Multiple holding pressures and holding times for maintaining that holding pressure may be set, and these may be set together as a series of setting conditions.

[0081] During the holding pressure process, the molding material in the cavity space 801 within the mold device 800 is gradually cooled, and upon completion of the holding pressure process, the entrance to the cavity space 801 is sealed with solidified molding material. This state is called a gate seal, and prevents backflow of molding material from the cavity space 801. After the holding pressure process, the cooling process begins. During the cooling process, the molding material in the cavity space 801 is solidified. To shorten the molding cycle time, a metering process may be performed during the cooling process.

[0082] In this embodiment, the injection device 300 is an in-line screw type, but a pre-plasticization type or the like may also be used. In a pre-plasticization injection device, the molding material molten in a plasticizing cylinder is supplied to the injection cylinder, and the molding material is injected from the injection cylinder into the mold device. In the plasticizing cylinder, a screw is arranged to be rotatable but unable to move back and forth, or a screw is arranged to be rotatable and able to move back and forth. On the other hand, a plunger is arranged to be able to move back and forth in the injection cylinder.

[0083] Furthermore, although the injection device 300 in this embodiment is a horizontal type with the axial direction of the cylinder 310 being horizontal, it may also be a vertical type with the axial direction of the cylinder 310 being vertical. The clamping device combined with the vertical injection device 300 may be vertical or horizontal. Similarly, the clamping device combined with the horizontal injection device 300 may be horizontal or vertical.

[0084] (Mobile device) In describing the moving device 400, similar to the description of the injection device 300, the direction of movement of the screw 330 during filling (for example, the negative X-axis direction) is described as forward, and the direction of movement of the screw 330 during metering (for example, the positive X-axis direction) is described as backward.

[0085] The moving device 400 moves the injection device 300 forward and backward relative to the mold device 800. The moving device 400 also presses the nozzle 320 against the mold device 800, generating nozzle touch pressure. The moving device 400 includes a hydraulic pump 410, a motor 420 as a drive source, a hydraulic cylinder 430 as a hydraulic actuator, and the like.

[0086] The hydraulic pump 410 has a first port 411 and a second port 412. The hydraulic pump 410 is a bidirectional rotatable pump, and by switching the rotation direction of the motor 420, it can draw in working fluid (e.g., oil) from either the first port 411 or the second port 412 and discharge it from the other to generate hydraulic pressure. The hydraulic pump 410 can also draw working fluid from a tank and discharge it from either the first port 411 or the second port 412.

[0087] Motor 420 operates the hydraulic pump 410. Motor 420 drives the hydraulic pump 410 with a rotational direction and rotational torque corresponding to the control signal from the control device 700. Motor 420 may be an electric motor or an electric servo motor.

[0088] The hydraulic cylinder 430 comprises a cylinder body 431, a piston 432, and a piston rod 433. The cylinder body 431 is fixed to the injection device 300. The piston 432 divides the inside of the cylinder body 431 into a front chamber 435 as a first chamber and a rear chamber 436 as a second chamber. The piston rod 433 is fixed to the fixed platen 110.

[0089] The front chamber 435 of the hydraulic cylinder 430 is connected to the first port 411 of the hydraulic pump 410 via the first passage 401. The hydraulic fluid discharged from the first port 411 is supplied to the front chamber 435 via the first passage 401, pushing the injection device 300 forward. As the injection device 300 moves forward, the nozzle 320 is pressed against the fixed mold 810. The front chamber 435 functions as a pressure chamber that generates nozzle touch pressure on the nozzle 320 due to the pressure of the hydraulic fluid supplied from the hydraulic pump 410.

[0090] Meanwhile, the rear chamber 436 of the hydraulic cylinder 430 is connected to the second port 412 of the hydraulic pump 410 via the second passage 402. The working fluid discharged from the second port 412 is supplied to the rear chamber 436 of the hydraulic cylinder 430 via the second passage 402, pushing the injection device 300 backward. As a result, the injection device 300 is retracted, and the nozzle 320 is separated from the fixed mold 810.

[0091] In this embodiment, the moving device 400 includes a hydraulic cylinder 430, but the present invention is not limited thereto. For example, instead of the hydraulic cylinder 430, an electric motor and a motion conversion mechanism that converts the rotational motion of the electric motor into the linear motion of the injection device 300 may be used.

[0092] (Control device) The control device 700 is, for example, a computer and, as shown in Figures 1 and 2, has a CPU (Central Processing Unit) 701, a storage medium 702 such as memory, an input interface 703, and an output interface 704. The control device 700 performs various controls by having the CPU 701 execute a program stored in the storage medium 702. The control device 700 also receives signals from the outside through the input interface 703 and transmits signals to the outside through the output interface 704.

[0093] The control device 700 includes electronic circuits such as a CPU, FPGA (Field Programmable Gate Array), or ASIC (Application Specific Integrated Circuit), and performs various control operations described in this specification by executing instruction codes stored in memory or by designing the circuit for special applications.

[0094] The control device 700 repeatedly manufactures molded products by repeatedly performing processes such as metering, mold closing, pressure increasing, mold clamping, filling, holding pressure, cooling, depressurization, mold opening, and ejection. A series of operations to obtain a molded product, such as the operations from the start of one metering process to the start of the next metering process, is also called a "shot" or "molding cycle." The time required for one shot is also called the "molding cycle time" or "cycle time."

[0095] A single molding cycle includes, for example, a weighing process, a mold closing process, a pressurizing process, a clamping process, a filling process, a holding pressure process, a cooling process, a depressurizing process, a mold opening process, and an ejection process, in this order. The order here refers to the order in which each process begins. The filling, holding pressure, and cooling processes take place during the clamping process. The start of the clamping process may coincide with the start of the filling process. The completion of the depressurizing process coincides with the start of the mold opening process.

[0096] Furthermore, multiple processes may be performed simultaneously in order to shorten the molding cycle time. For example, the metering process may be performed during the cooling process of the previous molding cycle, or during the mold clamping process. In this case, the mold closing process may be performed at the beginning of the molding cycle. The filling process may also be started during the mold closing process. The ejection process may also be started during the mold opening process. If an on-off valve is provided to open and close the flow path of the nozzle 320, the mold opening process may be started during the metering process. This is because even if the mold opening process is started during the metering process, if the on-off valve closes the flow path of the nozzle 320, the molding material will not leak from the nozzle 320.

[0097] Furthermore, a single molding cycle may include steps other than the weighing process, mold closing process, pressurization process, mold clamping process, filling process, holding pressure process, cooling process, depressurization process, mold opening process, and ejection process.

[0098] For example, after the holding pressure process is completed and before the metering process begins, a pre-metering suck-back process may be performed in which the screw 330 is retracted to a preset metering start position. This reduces the pressure of the molding material accumulated in front of the screw 330 before the metering process begins and prevents the screw 330 from retracting abruptly at the start of the metering process.

[0099] Furthermore, after the metering process is completed and before the filling process begins, a post-metering suck-back process may be performed in which the screw 330 is retracted to a predetermined filling start position (also called the "injection start position"). This reduces the pressure of the molding material accumulated in front of the screw 330 before the filling process begins and prevents leakage of the molding material from the nozzle 320 before the filling process begins.

[0100] The control device 700 is connected to an operating device 750 that accepts user input operations and a display device 760 that displays a screen. The operating device 750 and the display device 760 may be integrated, for example, by a touch panel 770. The touch panel 770, as the display device 760, displays a screen under the control of the control device 700. The screen of the touch panel 770 may display information such as the settings of the injection molding machine 10 and the current status of the injection molding machine 10. The screen of the touch panel 770 may also display operation parts such as buttons and input fields that accept user input operations. The touch panel 770, as the operating device 750, detects user input operations on the screen and outputs a signal corresponding to the input operation to the control device 700. This allows, for example, the user to operate the operation parts provided on the screen while confirming the information displayed on the screen to set the injection molding machine 10 (including inputting setting values). Furthermore, by operating the operation parts provided on the screen, the user can make the injection molding machine 10 operate in accordance with the operation part. Furthermore, the operation of the injection molding machine 10 may also include the operation (including stopping) of, for example, the clamping device 100, the ejector device 200, the injection device 300, the moving device 400, etc. Alternatively, the operation of the injection molding machine 10 may also include switching the screen displayed on the touch panel 770, which serves as the display device 760.

[0101] Although the operating device 750 and display device 760 of this embodiment have been described as being integrated as a touch panel 770, they may be provided independently. Furthermore, multiple operating devices 750 may be provided. The operating device 750 and display device 760 are positioned on the operating side (negative Y-axis direction) of the clamping device 100 (more specifically, the fixed platen 110).

[0102] (Details of the injection device) Next, with reference to Figure 3, the details of the injection device 300 will be described. The injection device 300 includes, for example, a cylinder 310 for heating the molding material and a screw 330 provided inside the cylinder 310. The injection device 300 rotates the screw 330 to feed the molding material from the upstream side to the downstream side (from right to left in Figure 3) along the helical groove formed in the screw 330. Hereinafter, the upstream side may be referred to as the rear and the downstream side as the front.

[0103] The cylinder 310 is divided into multiple (e.g., five) zones Z0 to Z4 along its axial direction (e.g., the X-axis direction). A cooler 312 is provided in the upstream zone Z0, and a first heater 313 and a first temperature detector 314 are provided in each of the remaining zones Z1 to Z4. A set temperature is set for each of the multiple zones Z0 to Z4. Note that the number of zones is not limited to five.

[0104] The control device 700 provides feedback control to the temperature of the temperature-controlled medium supplied to the cooler 312 through the temperature-controlled channel 317 and the solenoid valve 315, or the temperature of the cooler 312 cooled by the temperature-controlled medium, so that the actual temperature of zone Z0 becomes the set temperature. The temperature-controlled channel 317 includes, for example, a through hole provided in the cooler 312 and piping connected to the through hole. The solenoid valve 315 is provided in the middle of the piping of the temperature-controlled channel 317 and opens and closes the temperature-controlled channel 317.

[0105] The cooler 312 cools the supply port 311 of the molding material by passing a temperature-controlled medium through the temperature-controlled flow path 317, thereby suppressing a phenomenon called bridging. Bridging is a phenomenon in which resin pellets, which are the molding material, melt and clog the supply port. The cooler 312 is, for example, a water-cooled cylinder. The temperature-controlled medium is, for example, cooling water. The cooler 312 has a cooling temperature detector 316, for example, a thermocouple. Alternatively, the solenoid valve 315 may also have a cooling temperature detector 316.

[0106] Furthermore, the control device 700 detects the actual temperature of each of the multiple zones Z1 to Z4 using the first temperature detector 314, and individually feedback-controls the output of the first heater 313 for each zone Z1 to Z4 so that the actual temperature detected by the first temperature detector 314 becomes the set temperature. The multiple first heaters 313 may have the same configuration or different configurations. The first heater 313 is, for example, a band heater.

[0107] The output of the first heater 313 is expressed, for example, as the percentage of energizing time per unit time. The larger the percentage of energizing time, the greater the output of the first heater 313. Although not shown, if multiple first heaters 313 are provided in one zone, the percentage of energizing time for all of these first heaters 313 is controlled to be the same. Also, although not shown, multiple first temperature detectors 314 may be provided in one zone. The number of zones, the number of first heaters 313, and the number of first temperature detectors 314 do not have to be the same.

[0108] A nozzle 320 is attached to the front end of the cylinder 310. The nozzle 320 is pressed against the mold device 800 (see Figures 1 and 2) and injects pre-molten molding material into the mold device 800. A second heater 323 and a second temperature detector 324 are provided on the outer circumference of the nozzle 320. The second heater 323 and the second temperature detector 324 are located in zone Z5. The nozzle 320 and the second heater 323 constitute a nozzle assembly 303. The nozzle assembly 303 may also include the second temperature detector 324.

[0109] The control device 700 detects the actual temperature of zone Z5 using the second temperature detector 324 and provides feedback control to the output of the second heater 323 so that the actual temperature detected by the second temperature detector 324 becomes the set temperature. The second heater 323 is, for example, a coil heater or a band heater. The output of the second heater 323 is expressed, for example, as the percentage of energizing time per unit time.

[0110] Furthermore, the nozzle 320, like the cylinder 310, may be divided into multiple zones in the X-axis direction. A second heater 323 and a second temperature detector 324 are provided in each of the multiple zones. In this case, the control device 700 individually feedback-controls the output of the second heater 323 for each zone. The multiple second heaters 323 may have the same configuration or different configurations.

[0111] The screw 330 is rotatably and reciprocally positioned within the cylinder 310. When the metering motor 340 rotates the screw 330, the molding material is fed forward along the helical groove of the screw 330. As the molding material is fed forward, it is gradually melted by the heat from the cylinder 310.

[0112] As the liquid molding material is fed forward to the screw 330 and accumulates in the front of the cylinder 310, the screw 330 is retracted. Then, when the injection motor 350 moves the screw 330 forward, the liquid molding material accumulated in front of the screw 330 is injected from the nozzle 320 and filled into the mold device 800. The screw 330 pushes the molding material forward.

[0113] The nozzle 320 forms a flow channel 321 inside through which the molding material flows from rear to front. The flow channel 321 has a pocket A0 at its rear end. The front end of the screw 330 is inserted into the pocket A0. The diameter of the pocket A0 narrows towards the front. The diameter of the pocket A0 at its front end is smaller than the outer diameter of the screw 330. It is physically impossible for the screw 330 to move forward beyond the pocket A0.

[0114] (Injection molding system) Next, with reference to Figures 4 to 9, embodiments of the injection molding system and injection molding machine according to this disclosure will be described.

[0115] Figure 4 is a circuit diagram showing the path of the temperature-controlled medium TM in the injection molding system SYS of this embodiment. The injection molding system SYS comprises a plurality of injection molding machines 10, each having a temperature-controlled channel 317 through which the temperature-controlled medium TM passes, and a solenoid valve 315 that opens and closes the temperature-controlled channel 317. Each injection molding machine 10 has, for example, the configuration described with reference to Figures 1 to 3. The plurality of injection molding machines 10 are installed, for example, in a factory and connected in series to a supply channel SL that supplies cooling water such as groundwater as the temperature-controlled medium TM. The plurality of injection molding machines 10 are also connected in series to, for example, a recovery channel RL that recovers the temperature-controlled medium TM.

[0116] In the example shown in Figure 4, the temperature-controlled medium TM is cooled by the chiller unit CU and supplied from the chiller unit CU to each injection molding machine 10 via the supply path SL. The temperature-controlled medium TM supplied to each injection molding machine 10 passes through the solenoid valve 315 of each injection molding machine 10 and then through the temperature-controlled flow path 317 of each injection molding machine 10. As a result, for example, the cooler 312 of the injection device 300 and the fixed mold 810 and movable mold 820 of the mold device 800 are cooled by the temperature-controlled medium TM. The temperature-controlled medium TM, whose temperature has risen after passing through the temperature-controlled flow path 317 of each injection molding machine 10, is collected in the chiller unit CU via the recovery path RL connected to the outlet of each temperature-controlled flow path 317 and cooled again in the chiller unit CU. The injection molding system SYS may also include the chiller unit CU, the supply path SL, and the recovery path RL.

[0117] The injection molding system SYS comprises multiple injection molding machines 10, including one or more upstream molding machines 10U and one or more downstream molding machines 10D. The upstream molding machine 10U is connected to the upstream section US of the supply line SL. The downstream molding machine 10D is connected to the downstream section DS of the supply line SL, where the pressure of the temperature-controlled medium TM is lower than that of the upstream section US. The most distinctive feature of the injection molding system SYS of this embodiment is that the opening and closing force of the solenoid valve 315 of the upstream molding machine 10U is greater than the opening and closing force of the solenoid valve 315 of the downstream molding machine 10D.

[0118] The upstream portion US of the supply channel SL is, for example, the upstream portion of the supply channel SL in the direction of flow of the temperature-controlled medium TM, where the pressure of the temperature-controlled medium TM is higher than a threshold. The downstream portion DS of the supply channel SL is, for example, the downstream portion of the supply channel SL from the upstream portion US in the direction of flow of the temperature-controlled medium TM, where the pressure of the temperature-controlled medium TM is lower than a threshold. The threshold pressure of the temperature-controlled medium TM is, for example, the maximum operating pressure of the solenoid valve 315 of the downstream molding machine 10D. The number of upstream molding machines 10U and downstream molding machines 10D is not particularly limited.

[0119] Figure 5 is a schematic diagram showing an example configuration of a solenoid valve 315 in a downstream molding machine 10D included in a plurality of injection molding machines 10. The solenoid valve 315 of the downstream molding machine 10D is, for example, a DC solenoid valve 315dc driven by a DC current. The temperature control channel 317 includes an upstream pipe 317a connected to a supply channel SL for the temperature control medium TM and a downstream pipe 317b connected to a recovery channel RL for the temperature control medium TM. The DC solenoid valve 315dc is installed, for example, in the middle of the upstream pipe 317a of the temperature control channel 317.

[0120] In the example shown in Figure 5, the downstream molding machine 10D is equipped with a distribution valve 318 that distributes a temperature-controlled medium TM to the temperature-controlled flow path 317 of the injection device 300 and the temperature-controlled flow path 317 of the mold device 800. The distribution valve 318 has, for example, a supply flow path and a recovery flow path that penetrate the main body of the distribution valve 318 in the longitudinal direction. The supply flow path of the distribution valve 318 is connected in the middle of the upstream piping 317a of the temperature-controlled flow path 317, and connects the upstream and downstream sides of the upstream piping 317a. The recovery flow path of the distribution valve 318 is connected in the middle of the downstream piping 317b of the temperature-controlled flow path 317, and connects the upstream and downstream sides of the downstream piping 317b.

[0121] Furthermore, the temperature control channel 317 includes, for example, a plurality of supply pipes 317c connected to the supply channel of the distribution valve 318, and a plurality of recovery pipes 317d connected to the recovery channel of the distribution valve 318. The supply pipes 317c and recovery pipes 317d are connected to the inlet and outlet of through-holes that penetrate the fixed mold 810 or the movable mold 820 and constitute the temperature control channel 317 of the mold apparatus 800, respectively. Although not shown in the figures, the distribution valve 318 has, for example, a plurality of valves that can open and close the supply pipes 317c and recovery pipes 317d, respectively.

[0122] The upstream piping 317a of the temperature control channel 317 is equipped with a manually operated valve 319 downstream of the distribution valve 318 in the flow direction of the temperature control medium TM, and further downstream is a DC solenoid valve 315dc that can be opened and closed automatically. Downstream of the solenoid valve 315, the upstream piping 317a of the temperature control channel 317 penetrates the cooler 312 shown in Figure 3 and is connected to the inlet of the through-hole that constitutes the temperature control channel 317 of the injection device 300.

[0123] The downstream pipe 317b of the temperature-controlled flow path 317 is connected to the outlet of the through-hole that constitutes the temperature-controlled flow path 317 of the injection device 300, passing through the cooler 312 shown in Figure 3, upstream of the distribution valve 318 in the flow direction of the temperature-controlled medium TM. The downstream end of the portion of the downstream pipe 317b upstream of the distribution valve 318 in the flow direction of the temperature-controlled medium TM is connected to the inlet of the recovery flow path of the distribution valve 318, and the upstream end of the portion downstream of the distribution valve 318 is connected to the outlet of the recovery flow path of the distribution valve 318. The downstream end of the downstream pipe 317b in the flow direction of the temperature-controlled medium TM is connected to the recovery path RL shown in Figure 4.

[0124] In the example shown in Figure 5, the downstream molding machine 10D is equipped with a temperature control device 710 in addition to the control device 700. The temperature control device 710 may be part of the control device 700. The temperature control device 710 is, for example, a temperature control board on which electronic components such as a microcontroller and relays are mounted. The temperature control device 710 is mounted, for example, on the frame 900 that supports the injection device 300 shown in Figures 1 and 2.

[0125] The temperature control device 710 is connected to, for example, a cooling temperature detector 316 that detects the temperature of the temperature control medium TM or the cooler 312, and acquires the detection result of the cooling temperature detector 316. The temperature control device 710 is also connected to, for example, a power supply 711 that can supply current to the solenoid valve 315. The power supply 711 is, for example, a DC power supply that can supply DC current to the DC solenoid valve 315dc.

[0126] Figure 6 is a block diagram showing an example of control of the solenoid valve 315 in Figure 5. The temperature control device 710 includes, for example, a temperature detection unit 712 and a temperature control unit 713. Each part of the temperature control device 710 shown in Figure 6 represents the functions of the temperature control device 710, which are realized by executing a program by a processing unit that constitutes the microcontroller of the temperature control device 710.

[0127] The temperature detection unit 712 acquires a signal S corresponding to the temperature of the temperature control medium TM or the cooler 312 detected by the cooling temperature detector 316, and outputs a temperature Ts corresponding to the signal S. The temperature control unit 713 outputs a current command DCC to the solenoid valve 315 corresponding to the difference ΔT between the target value Tc of the cooling temperature input from the control device 700 and the temperature Ts output from the temperature detection unit 712, thereby opening and closing the solenoid valve 315.

[0128] The current command DCC is, for example, a DC current corresponding to the energizing time of the DC solenoid valve 315dc. This causes the DC solenoid valve 315dc to close in accordance with the current command DCC, and the flow rate of the temperature-controlled medium TM supplied to the cooler 312 via the temperature-controlled flow path 317 is adjusted. In other words, the DC solenoid valve 315dc is a normally open solenoid valve that remains open when not energized.

[0129] Figure 7 is a schematic diagram showing an example configuration of the solenoid valve 315 of the upstream molding machine 10U included in a plurality of injection molding machines 10. Figure 8 is a schematic diagram showing another example configuration of the solenoid valve 315 of the upstream molding machine 10U.

[0130] The upstream molding machine 10U shown in Figure 7 differs from the downstream molding machine 10D shown in Figure 5 in that it has a power amplifier 720 that amplifies the current supplied to the solenoid valve 315. Furthermore, the upstream molding machine 10U shown in Figure 8 differs from the downstream molding machine 10D shown in Figure 5 in that it has both a power amplifier 720 and an AC solenoid valve 315ac. The other configurations of the upstream molding machine 10U in Figures 7 and 8 are the same as those of the downstream molding machine 10D shown in Figure 5, so the same reference numerals are used for the same parts and their explanation is omitted.

[0131] In the example shown in Figure 7, the solenoid valve 315 of the upstream molding machine 10U is a DC solenoid valve 315dc driven by DC current, similar to the downstream molding machine 10D shown in Figure 5. The power amplifier 720 is detachably mounted in the upstream molding machine 10U at a position where it can be connected to the DC solenoid valve 315dc and the power supply 711. Specifically, the power amplifier 720 is detachably mounted, for example, on the frame 900 that supports the injection device 300 shown in Figures 1 and 2, and has a configuration that amplifies the current output from the temperature control device 710 and supplies it to the solenoid valve 315.

[0132] Here, "detachable" means that parts can be attached to and removed from the injection molding machine 10, which is installed as equipment in a customer's factory or other facility, without having to relocate or remove it from the premises. In other words, "detachable" means that, for example, if the necessity of a part changes due to a change in the layout of the factory, the part can be attached to an injection molding machine 10 that does not have the part, and the part can be removed from an injection molding machine 10 that no longer needs the part.

[0133] On the other hand, in the example shown in Figure 8, the solenoid valve 315 that opens and closes the temperature control channel 317 of the upstream molding machine 10U is an AC solenoid valve 315ac driven by AC current. The power amplifier 720 also has a mechanical relay 721 driven by DC current. The power amplifier 720 is connected to an AC power supply 722 that supplies AC current to the AC solenoid valve 315ac when the mechanical relay 721 is turned on.

[0134] More specifically, in the example shown in Figure 8, the solenoid valve 315 of the upstream molding machine 10U includes a DC solenoid valve 315dc connected to a distribution valve 318, similar to the downstream molding machine 10D shown in Figure 5. However, in the example shown in Figure 8, the DC solenoid valve 315dc is not energized and remains in the open state. Furthermore, the AC solenoid valve 315ac is located downstream of the DC solenoid valve 315dc in the flow direction of the temperature-controlled medium TM, and is detachably attached to the upstream piping 317a via a piping connection component.

[0135] In other words, in the example shown in Figure 8, the solenoid valve 315 of the upstream molding machine 10U includes a DC solenoid valve connected to the distribution valve 318 to keep the temperature control channel 317 normally open, and a detachable AC solenoid valve 315ac that opens and closes the temperature control channel 317. In contrast, in the example shown in Figure 5, the solenoid valve 315 of the downstream molding machine 10D is a DC solenoid valve 315dc connected to the distribution valve 318 to open and close the temperature control channel 317.

[0136] Figure 9 is a block diagram showing an example of control of the solenoid valve 315 of the upstream molding machine 10U as shown in Figure 7 or Figure 8. As shown in Figure 7, when the solenoid valve 315 that opens and closes the temperature control channel 317 of the upstream molding machine 10U is a DC solenoid valve 315dc, the power amplifier 720 supplies a DC current, which is an amplified DC current command DCC output from the temperature control unit 713, to the DC solenoid valve 315dc. This makes it possible to make the opening and closing force of the DC solenoid valve 315dc, which is the solenoid valve 315 of the upstream molding machine 10U as shown in Figure 7, greater than the opening and closing force of the DC solenoid valve 315dc, which is the solenoid valve 315 of the downstream molding machine 10D as shown in Figure 5.

[0137] On the other hand, as shown in Figure 8, if the solenoid valve 315 that opens and closes the temperature control channel 317 of the upstream molding machine 10U is an AC solenoid valve 315ac, the power amplifier 720 turns on the mechanical relay 721 in response to the current command DCC output from the temperature control unit 713. As a result, an AC current amplified more than the current command DCC is supplied from the AC power supply 722 to the AC solenoid valve 315ac via the power amplifier 720. This makes it possible to make the opening and closing force of the AC solenoid valve 315ac, which is the solenoid valve 315 of the upstream molding machine 10U shown in Figure 8, greater than the opening and closing force of the DC solenoid valve 315dc, which is the solenoid valve 315 of the downstream molding machine 10D shown in Figure 5.

[0138] The operation of the injection molding system SYS and injection molding machine 10 of this embodiment will be described below.

[0139] For example, in a factory, a temperature-controlled medium TM is supplied to multiple injection molding machines 10 connected in series to the supply channel SL via the supply channel SL. However, due to precipitates of the temperature-controlled medium TM accumulating in the supply channel SL, the pressure of the temperature-controlled medium TM may decrease downstream of the supply channel SL. In such cases, if the pressure of the temperature-controlled medium TM supplied to the temperature-controlled flow path 317 of the injection molding machine 10 connected downstream of the supply channel SL is increased to the required pressure, the pressure of the temperature-controlled medium TM upstream of the supply channel SL may rise excessively. In such cases, there is a risk of interference with the opening and closing of the solenoid valve 315 that opens and closes the temperature-controlled flow path 317 of the injection molding machine 10 connected upstream of the supply channel SL.

[0140] In contrast, the injection molding system SYS of this embodiment comprises a plurality of injection molding machines 10 connected in series to a supply passage SL for the temperature-controlled medium TM. Each injection molding machine 10 has a temperature-controlled passage 317 through which the temperature-controlled medium TM passes, and a solenoid valve 315 that opens and closes the temperature-controlled passage 317. These plurality of injection molding machines 10 include an upstream molding machine 10U connected to the upstream part US of the supply passage SL, and a downstream molding machine 10D connected to the downstream part DS of the supply passage SL where the pressure of the temperature-controlled medium TM is lower than that of the upstream part US. The opening and closing force of the solenoid valve 315 of the upstream molding machine 10U is greater than the opening and closing force of the solenoid valve 315 of the downstream molding machine 10D.

[0141] With this configuration, according to the injection molding system SYS of this embodiment, even if the pressure of the temperature-controlled medium TM supplied to the temperature-controlled flow path 317 in the upstream molding machine 10U connected to the upstream part US of the supply path SL rises above that of the downstream part DS of the supply path SL, the solenoid valve 315 can be opened and closed. Specifically, the opening and closing force of the solenoid valve 315 of the upstream molding machine 10U is greater than the opening and closing force of the solenoid valve 315 of the downstream molding machine 10D. Therefore, even if the pressure of the temperature-controlled medium TM rises to such an extent that it interferes with the opening and closing of the solenoid valve 315 of the downstream molding machine 10D in the upstream part US of the supply path SL, the solenoid valve 315 of the upstream molding machine 10U can be opened and closed without any problems.

[0142] As a result, the temperature of the cooler 312 shown in Figure 3 stabilizes in the multiple injection molding machines 10 that make up the injection molding system SYS, and the temperature of the rear side (positive X-axis side in Figure 3) of the cylinder 310 also stabilizes. This reduces variations in molding material temperature, metering time, and filling pressure among the multiple injection molding machines 10, and improves the stability of logging monitoring. Consequently, the number of defective shots decreases in each injection molding machine 10, and the yield rate of injection molded products improves. Furthermore, in a factory, for example, the upstream US of the supply path SL, where the temperature control medium TM is at a pressure higher than the threshold, hardly fluctuates and remains fixed. Therefore, by designating only the injection molding machine 10 connected to the upstream US of the supply path SL as the upstream molding machine 10U, the overall cost of the injection molding system SYS can be reduced.

[0143] Furthermore, in the injection molding system SYS of this embodiment, the upstream molding machine 10U has a power amplifier 720 that amplifies the current supplied to the solenoid valve 315.

[0144] With this configuration, among the multiple injection molding machines 10 connected in series to the supply path SL, the power amplifier 720 can be attached to the injection molding machine 10 that may have a pressure exceeding the threshold of the temperature control medium TM, potentially causing problems with the opening and closing of the solenoid valve 315, thereby changing it to an upstream molding machine 10U. As a result, in the upstream molding machine 10U, which is supplied with a temperature control medium TM at a pressure exceeding the threshold, the opening and closing force of the solenoid valve 315 that opens and closes the temperature control flow path 317 is increased to be greater than the opening and closing force of the solenoid valve 315 in the downstream molding machine 10D, allowing the solenoid valve 315 to be opened and closed without problems.

[0145] Furthermore, in the example shown in Figure 8 of the injection molding system SYS of this embodiment, the solenoid valve 315 that opens and closes the temperature control channel 317 of the upstream molding machine 10U is an AC solenoid valve 315ac driven by AC current. The power amplifier 720 has a mechanical relay 721 driven by DC current and is connected to an AC power supply 722 that supplies AC current to the AC solenoid valve 315ac when the mechanical relay 721 is turned on.

[0146] With this configuration, the power amplifier 720 supplies amplified AC current to the AC solenoid valve 315ac of the upstream molding machine 10U, making the opening and closing force of the solenoid valve 315 of the upstream molding machine 10U greater than that of the solenoid valve 315 of the downstream molding machine 10D. Furthermore, the AC solenoid valve 315ac that opens and closes the temperature control channel 317 can be energized with an AC current whose maximum current value is greater than the maximum DC current value in the upstream molding machine 10U. As a result, it becomes possible to increase the opening and closing force of the AC solenoid valve 315ac that opens and closes the temperature control channel 317 in the upstream molding machine 10U.

[0147] Furthermore, in the example of the injection molding system SYS of this embodiment shown in Figure 7, the solenoid valve 315 of the upstream molding machine 10U is a DC solenoid valve 315dc that is driven by a DC current.

[0148] This configuration allows the use of a common DC solenoid valve 315dc for both the upstream molding machine 10U and the downstream molding machine 10D. Therefore, the downstream molding machine 10D can be changed to the upstream molding machine 10U simply by attaching a detachable power amplifier 720 to the downstream molding machine 10D. Consequently, there is no need to significantly alter the configuration of the multiple injection molding machines 10 included in the injection molding system SYS, and the upstream molding machine 10U and the downstream molding machine 10D can be easily swapped.

[0149] Furthermore, in the injection molding system SYS of this embodiment, the solenoid valve 315 of the downstream molding machine 10D is a DC solenoid valve 315dc that is driven by a DC current.

[0150] With this configuration, as shown in Figure 7, if the solenoid valve 315 of the upstream molding machine 10U is a DC solenoid valve 315dc, the solenoid valve 315 and its surrounding configuration can be standardized between the upstream molding machine 10U and the downstream molding machine 10D. Also, as shown in Figure 8, if the solenoid valve 315 that opens and closes the temperature control flow path 317 of the upstream molding machine 10U is an AC solenoid valve 315ac, the DC solenoid valve 315dc common to the downstream molding machine 10D can be kept normally open, and the AC solenoid valve 315ac can be installed downstream of it. Therefore, there is no need to significantly change the configuration of the multiple injection molding machines 10 included in the injection molding system SYS, and the upstream molding machine 10U and the downstream molding machine 10D can be easily swapped.

[0151] Furthermore, in the injection molding system SYS of this embodiment, each injection molding machine 10 is equipped with an injection device 300, a mold device 800, and a distribution valve 318. The injection device 300 melts and injects the molding material. The mold device 800 molds the molding material injected from the injection device 300. The distribution valve 318 distributes the temperature-controlled medium TM to the temperature-controlled flow path 317 of the injection device 300 and the temperature-controlled flow path 317 of the mold device 800. In the example shown in Figure 8, the solenoid valve 315 of the upstream molding machine 10U includes a DC solenoid valve 315dc connected to the distribution valve 318 to keep the temperature-controlled flow path 317 normally open, and a detachable AC solenoid valve 315ac that opens and closes the temperature-controlled flow path 317. Furthermore, as shown in Figure 5, the solenoid valve 315 of the downstream molding machine 10D is a DC solenoid valve 315dc that is connected to the distribution valve 318 and opens and closes the temperature control channel 317.

[0152] With this configuration, the downstream molding machine 10D, which integrates the distribution valve 318 and DC solenoid valve 315dc shown in Figure 5, can be converted into an upstream molding machine 10U by attaching the AC solenoid valve 315ac and power amplifier 720 shown in Figure 8. Therefore, the upstream molding machine 10U and the downstream molding machine 10D can be easily swapped without significantly changing the configuration of the injection molding machine 10, which integrates the DC solenoid valve 315dc and distribution valve 318.

[0153] Furthermore, the injection molding machine 10 of this embodiment includes an injection device 300 for melting and injecting a molding material, a temperature control channel 317 provided in the injection device 300, and a solenoid valve 315 that can open and close the temperature control channel 317. In addition, as shown in Figure 7 or Figure 8, the injection molding machine 10 of this embodiment includes a power supply 711 capable of supplying current to the solenoid valve 315, and a power amplifier 720 that is detachably mounted in a position where it can be connected to the solenoid valve 315 and the power supply 711, and is capable of amplifying the current from the power supply 711 and supplying it to the solenoid valve 315.

[0154] With this configuration, if the injection molding machine 10, without the power amplifier 720 installed, is connected to the upstream part US of the supply path SL and experiences difficulties in opening and closing the solenoid valve 315, the power amplifier 720 can be installed to increase the opening and closing force of the solenoid valve 315. Therefore, according to the injection molding machine 10 of this embodiment, even if the pressure of the temperature-controlled medium TM supplied to the temperature-controlled flow path 317, which is connected to the upstream part US of the supply path SL, rises, the solenoid valve 315 can be opened and closed without problems.

[0155] As described above, according to this embodiment, an injection molding system SYS and injection molding machine 10 can be provided that can open and close the solenoid valve 315 even when the pressure of the temperature-controlled medium TM supplied via the solenoid valve 315 rises.

[0156] Preferred embodiments of the present disclosure have been described above. However, the inventions of the present disclosure are not limited to the embodiments described above. Various modifications, substitutions, etc., can be applied to the embodiments described above without departing from the scope of the inventions of the present disclosure. Furthermore, each of the features described with reference to the embodiments described above may be combined as appropriate, as long as they do not contradict each other technically.

[0157] For example, a solenoid valve may be provided in the supply pipe 317c that supplies the temperature control medium TM from the distribution valve 318 shown in Figures 5, 7, and 8 to the fixed mold 810 or movable mold 820, and the opening and closing force of the solenoid valve of the upstream molding machine 10U may be greater than the opening and closing force of the solenoid valve of the downstream molding machine 10D. In this case, the mold temperature control unit attached externally to each injection molding machine 10 becomes unnecessary, and the pump used for the mold temperature control unit can be omitted, thereby reducing the power consumption of the injection molding system SYS. [Explanation of symbols]

[0158] 10 injection molding machine 10D Downstream Molding Machine 10U upstream molding machine 300 Injection device 315 Solenoid valve 315ac AC solenoid valve 315dc DC solenoid valve 317 Temperature control channel 318 Distribution valve 711 Power supply 720 Power Amplifier 721 Mechanical Relay 722 AC power supply 800 mold equipment 900 frames SL supply route SYS Injection Molding System TM Temperature control medium US upstream

Claims

1. An injection molding system comprising a plurality of injection molding machines, each having a temperature-controlled channel for passing a temperature-controlled medium and a solenoid valve for opening and closing the temperature-controlled channel, wherein the plurality of injection molding machines are connected in series to a supply path for the temperature-controlled medium, The plurality of injection molding machines include an upstream molding machine connected to the upstream part of the supply passage and a downstream molding machine connected to the downstream part of the supply passage where the pressure of the temperature-controlled medium is lower than that of the upstream part. The opening and closing force of the solenoid valve of the upstream molding machine is greater than the opening and closing force of the solenoid valve of the downstream molding machine. Injection molding system.

2. The upstream molding machine has a power amplifier that amplifies the current supplied to the solenoid valve. The injection molding system according to claim 1.

3. The solenoid valve of the upstream molding machine is an AC solenoid valve driven by an AC current, The power amplifier has a mechanical relay driven by a DC current and is connected to an AC power supply that supplies AC current to the AC solenoid valve when the mechanical relay is turned on. The injection molding system according to claim 2.

4. The solenoid valve of the upstream molding machine is a DC solenoid valve driven by a DC current. The injection molding system according to claim 2.

5. The solenoid valve of the downstream molding machine is a DC solenoid valve driven by a DC current. The injection molding system according to claim 3 or claim 4.

6. The injection molding machine comprises an injection device for melting and injecting a molding material, a mold device for molding the molding material injected from the injection device, and a distribution valve for distributing the temperature-controlled medium to the temperature-controlled passage of the injection device and the temperature-controlled passage of the mold device. The solenoid valve of the upstream molding machine includes a DC solenoid valve connected to the distribution valve to keep the temperature control channel normally open, and a detachable AC solenoid valve that opens and closes the temperature control channel. The solenoid valve of the downstream molding machine is a DC solenoid valve connected to the distribution valve and opening and closing the temperature control channel. The injection molding system according to claim 3.

7. An injection molding device that melts and injects molding material, A temperature control channel provided in the injection device, A solenoid valve capable of opening and closing the aforementioned temperature control channel, A power supply capable of supplying current to the solenoid valve, The system comprises a power amplifier that is detachably mounted in a position where it can be connected to the solenoid valve and the power supply, and which amplifies the current and supplies it to the solenoid valve. Injection molding machine.

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