Gas suction device for injection molding machine, and injection molding machine

Abstract

We provide technology for efficiently removing gases generated by the melting of resin pellets. [Solution] The gas suction device for an injection molding machine includes a suction pipe provided in the drop path through which resin pellets fall toward the screw. The suction pipe has a gas suction port toward the screw.

Description

Technical Field

[0001] The present invention relates to a gas suction device for an injection molding machine and an injection molding machine.

Background Art

[0002] The injection molding machine described in Patent Document 1 includes an ejection nozzle. The ejection nozzle injects an inert gas from a hopper toward a screw. The inert gas is, for example, nitrogen or argon. The inert gas suppresses oxidation (burning) of the resin.

[0003] The injection molding machine described in Patent Document 2 includes an exhaust device. The exhaust device discharges the gas generated by melting of resin pellets inside a cylinder from inside the cylinder. The exhaust device includes an exhaust pipe, a filter, and an exhaust fan.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] An injection molding machine has a dropping path for resin pellets. After the resin pellets drop through the dropping path, they are gradually melted while being sent forward along the spiral grooves of a screw. Gas is generated by melting of the resin pellets. The gas generation point is in front of the dropping path of the resin pellets.

[0006] The exhaust port of the exhaust pipe of Patent Document 2 is arranged behind the dropping path of the resin pellets. Therefore, from the gas generation point toward the rear, the dropping path and the exhaust port are arranged in this order. As a result, the gas may flow into the dropping path without reaching the exhaust port.

[0007] The gases generated by the melting of resin pellets, such as organic gases or water vapor, are lighter than air and can flow upwards along the drop path. Because the gases generated by the melting of resin pellets do not reach the exhaust port, the gas removal efficiency was low.

[0008] One embodiment of the present invention provides a technology for efficiently removing gas generated by the melting of resin pellets. [Means for solving the problem]

[0009] A gas suction device for an injection molding machine according to one embodiment of the present invention comprises a suction pipe provided in the drop path through which resin pellets fall toward the screw. The suction pipe has a gas suction port toward the screw. [Effects of the Invention]

[0010] According to one embodiment of the present invention, gas generated by the melting of resin pellets can be efficiently removed. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 shows the state of an injection molding machine upon completion of mold opening according to one embodiment. [Figure 2] Figure 2 shows the state of an injection molding machine during mold clamping according to one embodiment. [Figure 3] Figure 3 is a cross-sectional view showing an example of a gas suction device. [Figure 4] Figure 4 is a cross-sectional view showing an example of the arrangement of suction ports in a suction pipe. [Figure 5] Figure 5 is a cross-sectional view along the VV line in Figure 4. [Figure 6] Figure 6 is a cross-sectional view showing a modified example of Figure 3. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described below with reference to the drawings. In each drawing, identical or similar components are denoted by the same reference numerals, and their 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. Figure 2 shows the state of the injection molding machine when the mold is clamped according to one embodiment. 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 Figures 1 and 2, the injection molding machine 10 includes a clamping device 100 for opening and closing the mold device 800, an ejector device 200 for ejecting the molded product formed in the mold device 800, an injection device 300 for injecting molding material into the mold device 800, a moving device 400 for moving the injection device 300 forward and backward relative 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 clamping device frame 910 for supporting the clamping device 100 and an injection device frame 920 for supporting the injection device 300. The clamping device frame 910 and the injection device frame 920 are each installed on the floor 2 via leveling adjusters 930. The control device 700 is located in the internal space of the injection device frame 920. The components of the injection molding machine 10 will be described below.

[0015] (mold clamping device) In describing the mold 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.

[0016] The clamping device 100 performs mold closing, pressure boosting, 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 clamping device 100 is, for example, horizontal, and the mold opening / closing direction is the horizontal direction. The clamping device 100 has 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 that moves the movable platen 120 in the mold opening / closing direction with respect to the fixed platen 110.

[0018] The fixed platen 110 is fixed to the 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 arranged to be movable in the mold opening / closing direction with respect to the clamping device frame 910. A guide 101 for guiding the movable platen 120 is laid on the clamping device frame 910. The movable mold 820 is attached to the opposing surface of the movable platen 120 with respect to the fixed platen 110.

[0020] The moving mechanism 102 performs mold closing, pressure boosting, clamping, pressure release, and mold opening of the mold device 800 by advancing and retreating the movable platen 120 with respect to the fixed platen 110. The moving mechanism 102 has a toggle support 130 arranged at an interval 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 / closing direction with respect to the toggle support 130, a clamping motor 160 that operates the toggle mechanism 150, a motion conversion mechanism 170 that converts the rotational motion of the clamping motor 160 into a linear motion, and a mold thickness adjustment mechanism 180 that adjusts the interval 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. However, 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 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 part of the cavity space 801, and the molding material may be filled in the other part of the cavity space 801. A molded product in which the insert material and the molding material are integrated is obtained.

[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 depending on 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, a drive gear is attached to the output shaft of the mold thickness adjustment motor 183, and an intermediate gear that meshes with the multiple driven gears and the 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 a belt or pulley 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] In this embodiment, the clamping device 100 has a clamping motor 160 as a drive unit, but a hydraulic cylinder may be used instead of the clamping motor 160. Furthermore, 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 detected temperature of the nozzle 320 reaches a 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 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 able to move 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 is 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 may not be set at all.

[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 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 the holding pressure in the holding pressure process may be set, and 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 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 a 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 by 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 the injection device 300 is retracted, 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 step, mold closing step, pressurization step, mold clamping step, filling step, holding pressure step, cooling step, depressurization step, mold opening step, and ejection step.

[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 too quickly 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 preset 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. 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. Furthermore, the operation of the injection molding machine 10 may also include switching the screens 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 molding machine) Next, with reference to Figure 3, the details of the injection molding machine 10 will be described. The injection molding machine 10 includes, for example, a cylinder 310 for heating the molding material and a screw 330 provided inside the cylinder 310. The injection molding machine 10 feeds the molding material from the upstream side to the downstream side (from right to left in Figure 3) along a helical groove formed in the screw 330 by rotating the screw 330. The molding material is, for example, resin pellets 500. 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 refrigerant supplied from the refrigerant supplier 315 to the cooler 312 so that the actual temperature in zone Z0 becomes the set temperature. The cooler 312 suppresses a phenomenon called bridging by cooling the supply port 311 of the molding material. Bridging is a phenomenon in which the resin pellets 500 melt and clog the port. The cooler 312 is, for example, a water-cooled cylinder. The cooler 312 or the refrigerant supplier 315 may have a temperature sensor.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] The nozzle 320, like the cylinder 310, may also be divided into multiple zones in the X-axis direction. Each of the multiple zones is provided with a second heater 323 and a second temperature detector 324. 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.

[0110] 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.

[0111] 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.

[0112] The injection molding machine 10 has a drop channel 501 for resin pellets 500. The drop channel 501 is located directly above the supply port 311 of the cylinder 310. In the drop channel 501, the resin pellets 500 fall toward the screw 330. The screw 330 has a rotating shaft 332 and a flight 333. The flight 333 is spirally arranged around the outer circumference of the rotating shaft 332. The flight 333 forms a spiral groove.

[0113] The injection molding machine 10 includes a cylindrical member 502. The cylindrical member 502 forms a drop path 501. The cylindrical member 502 is, for example, part of a cooler 312. The cooler 312 is, for example, a water-cooled cylinder. The cooler 312 cools the supply port 311 of the cylinder 310, thereby suppressing a phenomenon called bridging at the supply port 311.

[0114] Furthermore, the cylindrical member 502 does not necessarily have to be part of the cooler 312. Even without the cooler 312, if there is an insulating member between the first heater 313 and the supply port 311 of the cylinder 310, the phenomenon called bridging at the supply port 311 can be suppressed. Therefore, the cylindrical member 502 does not need to have a cooling function.

[0115] After the resin pellets 500 fall along the drop path 501, they are gradually melted as they are fed forward along the spiral groove of the screw 330. The melting of the resin pellets 500 generates gas. The generated gas is, for example, an organic gas or water vapor, which is lighter than air. The point of gas generation is ahead of the drop path 501 of the resin pellets 500.

[0116] (Gas suction device) Next, an example of the gas suction device 600 will be described, mainly referring again to Figure 3. The gas suction device 600 includes a suction pipe 610. The suction pipe 610 draws in gas. The gas to be drawn in includes gas generated by the melting of the resin pellets 500. The gas to be drawn in may also include air or other substances.

[0117] The suction pipe 610 is installed in the drop path 501 for the resin pellets 500. This allows the suction pipe 610 to be placed closer to the gas generation point compared to when it is placed behind the drop path 501, enabling efficient removal of gas generated by the melting of the resin pellets 500.

[0118] The suction pipe 610 includes, for example, a vertical pipe 611 and a horizontal pipe 612. The horizontal pipe 612 is provided at the upper end of the vertical pipe 611. As shown in Figure 3, the horizontal pipe 612 extends backward (in the positive X-axis direction) from the upper end of the vertical pipe 611, but it may also extend towards the operating side (negative Y-axis direction) or the opposite operating side (positive Y-axis direction).

[0119] The suction pipe 610 has a gas suction port 613 facing the screw 330. The suction port 613 is positioned downwards, making it easier to draw gas from below. The suction port 613 is, for example, located at the lower end of a vertical pipe 611. In this case, the suction port 613 is positioned directly downwards.

[0120] Although not shown in the figures, the suction pipe 610 may have an inclined pipe. The inclined pipe extends diagonally downward from the lower end of the vertical pipe 611. The suction port 613 is provided at the lower end of the inclined pipe. The suction port 613 only needs to be positioned downward, and may be positioned diagonally downward rather than directly downward.

[0121] However, in order to reduce the effort required for bending the suction pipe 610, it is preferable that the suction pipe 610 does not have an inclined pipe. Similarly, in order to reduce the effort required for bending the suction pipe 610, it is preferable that the suction pipe 610 does not have a horizontal pipe 612. As shown in Figure 6, the suction pipe 610 may have only a vertical pipe 611.

[0122] The suction pipe 610 only needs to be provided in the drop path 501 of the cylindrical member 502, at least a portion of it. The lower end of the suction pipe 610, i.e., the suction port 613 of the suction pipe 610, may be provided in the supply port 311 of the cylinder 310. Although not shown, the suction port 613 of the suction pipe 610 may also be provided in the drop path 501 of the cylindrical member 502.

[0123] It is preferable that the distance D between the suction port 613 of the suction pipe 610 and the flight 333 of the screw 330 is 10 mm to 20 mm. If the distance D is 10 mm or more, it is possible to suppress the suction of the resin pellets 500 and dust attached to the resin pellets 500 to the suction port 613. If the distance D is 20 mm or less, the suction port 613 can efficiently draw in the gas.

[0124] As shown in Figure 3, the gas suction device 600 may include a vacuum ejector 620. The vacuum ejector 620 draws gas from the suction pipe 610. The vacuum ejector 620 has, for example, a nozzle, a diffuser, and a vacuum port. The nozzle discharges gas toward the diffuser, thereby reducing the pressure in the vacuum port. The vacuum port communicates with the suction port 613 of the suction pipe 610.

[0125] A vacuum pump can also be used instead of the vacuum ejector 620. However, the vacuum ejector 620 has a lower gas suction force compared to a vacuum pump. Therefore, using the vacuum ejector can suppress the attraction of the resin pellets 500 and any dust attached to them to the suction port 613. The gas suction force is not particularly limited, but is, for example, 2 slm to 10 slm. Here, "slm" means "standard liter per minute".

[0126] Even with low gas suction force, if the suction port 613 of the suction pipe 610 is positioned near the screw 330, the gas generated by the melting of the resin pellets 500 can be sufficiently drawn in. Furthermore, even with low gas suction force and low vacuum levels, the gas generated by the melting of the resin pellets 500 can be sufficiently drawn in, allowing for the omission or simplification of sealing work.

[0127] The gas suction device 600 may be equipped with a filter 630. The filter 630 removes dust from the gas on its way from the suction pipe 610 to the vacuum ejector 620. The filter 630 collects dust. Therefore, it is possible to prevent dust from entering the vacuum ejector 620 and to prevent malfunction of the vacuum ejector 620. The filter 630 may also collect chemical substances. The filter 630 may be replaced periodically to prevent a decrease in the gas suction force.

[0128] The filter 630 can be replaced while the adapter 640, described later, is attached to the cylindrical member 502. Similarly, the vacuum ejector 620 or the vacuum pump can be attached or detached while the adapter 640, described later, is attached to the cylindrical member 502.

[0129] The gas suction device 600 may be equipped with an adapter 640. The adapter 640 is attached to and detached from the upper surface of the cylindrical member 502 by bolts or the like. The suction pipe 610 is attached to and detached from the cylindrical member 502 together with the adapter 640 and extends from the adapter 640 to the drop path 501. By using the adapter 640, it is not necessary to machine a hole for the suction pipe 610 to pass through in the cooler 312 or the like.

[0130] The adapter 640 is installed between the cylindrical member 502 and the feeder 510. The feeder 510 drops the resin pellets 500 into the drop channel 501. The feeder 510 includes, for example, a hopper 511. The feeder 510 may also include a flange 512 provided at the lower end of the hopper 511. The feeder 510 does not necessarily include a hopper 511 and may include piping or a screw feeder (not shown).

[0131] The adapter 640 has a second drop path 641 for dropping the resin pellets 500 from the feeder 510 toward the cylindrical member 502. The resin pellets 500 pass through the second drop path 641 and the drop path 501 in that order. Also, as shown in Figure 4, the adapter 640 has a through hole 642 around the second drop path 641 through which the shaft portion 503a of the bolt 503 passes.

[0132] As shown in Figure 5, the shaft portion 503a of the bolt 503 passes through the through hole 513 in the flange 512 at the lower end of the feeder 510 and the through hole 642 in the adapter 640, and is screwed into the bolt hole 504 on the upper surface of the cylindrical member 502. The head 503b of the bolt 503 and the cylindrical member 502 secure the flange 512 at the lower end of the feeder 510 and the adapter 640 by sandwiching them together.

[0133] By loosening the bolt 503, the adapter 640 can be detached, and the flange 512 at the lower end of the feeder 510 can be fixed to the upper surface of the cylindrical member 502 without using the adapter 640. The length of the shaft portion 503a of the bolt 503 used is appropriately changed depending on whether the adapter 640 is attached to or removed from the upper surface of the cylindrical member 502.

[0134] The positions of the through-hole 513 in the flange 512 at the lower end of the feeder 510 and the bolt holes 504 in the cylindrical member 502 differ depending on the model number of the injection molding machine 10. Therefore, the adapter 640 may be provided with a through-hole 642 so that it can be applied to multiple models of injection molding machines 10.

[0135] For example, as shown in Figure 4, the through hole 642 of the adapter 640 may be an elongated hole. The through hole 642 may be a hole formed by connecting two elongated holes in an L-shape. As shown in Figure 4, the two elongated holes connected in an L-shape may be provided at each of the four corners of the rectangular adapter 640 when viewed from above.

[0136] If there are multiple through holes 642, at least one of the through holes 642 may be a round hole instead of an elongated hole. One through hole 642 is used in one injection molding machine 10, and another through hole 642 is used in another injection molding machine 10.

[0137] Incidentally, after the resin pellet 500 falls to the screw 330, it is fed along the helical groove of the screw 330 by the rotation of the screw 330. As shown in Figure 4, when viewed from above, the direction in which the resin pellet 500 is fed, which is parallel to the rotation centerline 330R of the screw 330 (negative X-axis direction), is the front side, and the opposite side (positive X-axis direction) is the rear side. Also, when viewed from above, the direction in which the resin pellet 500 is fed, which is perpendicular to the rotation centerline 330R of the screw 330 (positive Y-axis direction), is the back side, and the opposite side (negative Y-axis direction) is the front side.

[0138] As shown in Figure 4, when viewed from above, the area to the rear and front of the drop path 501 is designated as the first area A1, the area to the rear and back is designated as the second area A2, the area to the front and front is designated as the third area A3, and the area to the front and back is designated as the fourth area A4, with the center 501c of the drop path 501 as the reference point. When viewed from above, the shape of the drop path 501 is circular in this embodiment, but it may also be elliptical or rectangular, and is not particularly limited. When viewed from above, the center 501c of the drop path 501 may coincide with the rotation centerline 330R of the screw 330.

[0139] To consider the installation position of the suction port 613 of the suction pipe 610, we first consider the case where the suction pipe 610 is not installed in the drop path 501. In this case, there are no obstacles in the drop path 501 that would obstruct the fall of the resin pellets 500. Therefore, in this case, the density of the resin pellets 500 in the drop path 501 is the same in the first region A1, the second region A2, the third region A3, and the fourth region A4.

[0140] The resin pellets 500 falling through the first region A1 fall to the screw 330, and then are sent to the second region A2, the third region A3, and the fourth region A4 in that order. Similarly, the resin pellets 500 falling through the second region A2 fall to the screw 330, and then are sent to the third region A3 and the fourth region A4 in that order. Therefore, the density of the resin pellets 500 at the screw 330 is lowest in the first region A1, second lowest in the second region A2, third lowest in the third region A3, and highest in the fourth region A4.

[0141] As shown in Figure 4, when viewed from above, the suction port 613 of the suction pipe 610 is most preferably located in the first region A1. The density of the resin pellets 500 is lowest in the first region A1, which suppresses the attraction of the resin pellets 500 and dust attached to them to the suction port 613. When viewed from above, the region in which the suction port 613 is installed is most preferably the first region A1, second preferably the second region A2, third preferably the third region A3, and fourth preferably the fourth region A4.

[0142] Furthermore, if a suction port 613 is provided at the lower end of the vertical pipe 611, the vertical pipe 611 and the suction port 613 are located in the same position when viewed from above. As shown in Figure 4, when viewed from above, if the suction port 613 of the suction pipe 610 is located in the first region A1, the vertical pipe 611 is also located in the first region A1. As a result, the vertical pipe 611 can reduce the density of the resin pellets 500 falling in the first region A1.

[0143] The density of the resin pellets 500 in the screw 330 increases towards the front. Therefore, the suction port 613 of the suction pipe 610 may be positioned facing directly downwards. Compared to the case where the suction port 613 is positioned in a direction tilted forward from directly downwards, the case where it is positioned in a direction tilted to the side (forward or backward) from directly downwards, or in a direction tilted backward from directly downwards, can suppress the attraction of the resin pellets 500 and dust attached to the resin pellets 500 to the suction port 613.

[0144] The embodiments of the injection molding machine nozzle and injection molding machine according to the present invention have been described above, but the present invention is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope described in the claims. These also naturally fall within the technical scope of the present invention. [Explanation of Symbols]

[0145] 500 resin pellets 501 Drop Route 600 Gas suction device 610 Suction pipe 613 Suction port

Claims

1. It is equipped with a suction pipe located in the drop path through which the resin pellets fall toward the screw, The suction pipe has a gas suction port directed toward the screw, and is a gas suction device for an injection molding machine.

2. Viewed from above, the direction parallel to the rotational centerline of the screw and in which the resin pellets are fed is the front side, and the side opposite to the front side is the rear side. When viewed from above, if the direction perpendicular to the rotational centerline of the screw and the direction in which the resin pellets are fed is considered the rear side, and the opposite side is considered the front side, The gas suction device for an injection molding machine according to claim 1, wherein, when viewed from above, the suction port of the suction pipe is provided on the rear and front side with respect to the center of the drop path.

3. The gas suction device for an injection molding machine according to claim 1, wherein the suction port of the suction pipe is provided facing directly downward.

4. The gas suction device for an injection molding machine according to claim 1, further comprising a vacuum ejector for sucking the gas from the suction pipe.

5. The gas suction device for an injection molding machine according to claim 4, further comprising a filter to remove dust from the gas on the way from the suction pipe to the vacuum ejector.

6. The gas suction device for an injection molding machine according to claim 1, wherein the distance between the suction port of the suction pipe and the flight of the screw is 10 mm to 20 mm.

7. The cylindrical member forming the drop path is equipped with an adapter that can be attached to or detached from the upper surface of the cylindrical member, The gas suction device for an injection molding machine according to claim 1, wherein the suction pipe is attached to and detached from the cylindrical member together with the adapter and extends from the adapter to the drop path.

8. An injection molding machine comprising a gas suction device according to any one of claims 1 to 7, a cylindrical member forming the drop path, and the screw.

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