Injection molding machine

Abstract

To provide an injection molding machine that enables efficient cleaning of mold parting lines by allowing burrs to be formed through a simple configuration.SOLUTION: The injection molding machine 10 comprises a movable platen 120 having a movable mold 820, a fixed platen 110 having a fixed mold 810, a clamping device 100 having a toggle mechanism 150, an injection device 300, and a control device 700. The control unit 700 performs a cleaning process to form a molded part with a burr by injecting molding material via the injection unit 300 while the movable platen 120 is moved to a burr forming position, which is a position where the movable mold 820 is separated from the fixed mold 810 beyond the clamping position. The toggle mechanism 150 sets the toggle ratio to 1x or higher at the burr forming position.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to injection molding machines. [Background technology]

[0002] Patent Document 1 discloses a technique for adjusting the distance between the molds (movable mold, fixed mold) of an injection molding machine by using a hydraulic actuator to move a distance-increasing member in and out between the molds. By creating a distance between the molds in this way, the injection molding machine can intentionally form flash between the molds by injection molding and absorb and remove debris (resin mold deposits, gas adhesions, tar, etc.) that occurs at the boundary between the molds. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2013-16816 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if an injection molding machine is configured such that a distance-increasing member is installed in a mold unit as in Patent Document 1, it will encounter inconveniences such as increased manufacturing costs, layout restrictions, and structural complexity. In particular, if a distance-increasing member is installed in a mold unit every time the mold unit is replaced, a significant increase in costs is expected.

[0005] The present disclosure provides an injection molding machine that can efficiently clean the interface between molds by enabling flash to be formed using a simple configuration. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, there is provided an injection molding machine including: a movable platen having a movable mold; a fixed platen having a fixed mold opposing the movable mold; a clamping device having a toggle mechanism that moves the movable platen in a mold opening / closing direction relative to the fixed platen and can position the movable platen at a clamping position; an injection device that injects molding material into a cavity space formed by the movable mold and the fixed mold positioned at the clamping position; and a control device that controls the operation of the injection device and the clamping device, wherein the control device moves the movable platen to a burr molding position where the movable mold is further away from the fixed mold than the clamping position, and then injects the molding material using the injection device, thereby performing a cleaning process to mold a molded product having a burr, and the toggle mechanism has a toggle ratio of 1 or more at the burr molding position. [Effects of the Invention]

[0007] According to one aspect, by making it possible to form burrs using a simple configuration, the boundary surface between molds can be efficiently cleaned. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram showing a state when mold opening of the injection molding machine according to the embodiment is completed. [Figure 2] FIG. 2 is a diagram illustrating a state during mold clamping of the injection molding machine according to the embodiment. [Figure 3] FIG. 2 is a functional block diagram illustrating an example of components of a control device. [Figure 4] Fig. 4(A) is a diagram showing an example of a molding cycle process for injection molding, and Fig. 4(B) is a diagram showing an example of a molding cycle process for cleaning treatment. [Figure 5] Fig. 5(A) is a diagram showing the state of the mold clamping device for injection molding. Fig. 5(B) is a diagram showing mold thickness adjustment before cleaning processing. Fig. 5(C) is a diagram comparing the flash molding position after the mold closing step in cleaning processing with the mold clamping position for injection molding. [Figure 6] FIG. 4 is an enlarged view of a part of the toggle mechanism. [Figure 7] 1 is a first flowchart showing a method for performing a cleaning process. [Figure 8] 10 is a second flowchart showing the method for performing the cleaning process. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant explanations may be omitted.

[0010] (injection molding machine) Fig. 1 is a diagram showing the state of the injection molding machine according to the embodiment when mold opening is completed. Fig. 2 is a diagram showing the state of the injection molding machine according to the embodiment when mold clamping is performed. 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 of a horizontal type, the X-axis direction is the mold opening / closing direction, and the Y-axis direction is the width direction of the injection molding machine 10. The negative side of the Y-axis direction is called the operating side, and the positive side of the Y-axis direction is called the counter-operating side.

[0011] As shown in FIGS. 1 and 2 , injection molding machine 10 includes a mold clamping unit 100 that opens and closes mold apparatus 800, an ejector unit 200 that ejects a molded product molded by mold apparatus 800, an injection unit 300 that injects molding material into mold apparatus 800, a moving unit 400 that moves injection unit 300 forward and backward relative to mold apparatus 800, a control unit 700 that controls each component of injection molding machine 10, and a frame 900 that supports each component of injection molding machine 10. Frame 900 includes a mold clamping unit frame 910 that supports mold clamping unit 10 and an injection unit frame 920 that supports injection unit 300. Clamping unit frame 910 and injection unit frame 920 are each installed on floor 2 via leveling adjusters 930. Control unit 700 is disposed in the interior space of injection unit frame 920. Each component of injection molding machine 10 will be described below.

[0012] (mold clamping device) In the description of the mold clamping unit 100, the moving direction of the movable platen 120 during mold closing (for example, the positive X-axis direction) is defined as the front, and the moving direction of the movable platen 120 during mold opening (for example, the negative X-axis direction) is defined as the rear.

[0013] The mold clamping device 100 performs mold closing, pressure increase, mold clamping, depressurization, and mold opening of the mold device 800. The mold device 800 includes a fixed mold 810 and a movable mold 820.

[0014] The mold clamping unit 100 is, for example, a horizontal type, and the mold opening and closing direction is horizontal. The mold clamping unit 100 has a fixed platen 110 to which a fixed mold 810 is attached, a movable platen 120 to which a movable mold 820 is attached, and a movement mechanism 102 that moves the movable platen 120 relative to the fixed platen 110 in the mold opening and closing direction.

[0015] The stationary platen 110 is fixed to the mold clamping unit frame 910. A stationary mold 810 is attached to the surface of the stationary platen 110 that faces the movable platen 120.

[0016] The movable platen 120 is disposed so as to be movable in the mold opening / closing direction relative to the mold clamping unit frame 910. A guide 101 for guiding the movable platen 120 is installed on the mold clamping unit frame 910. A movable mold 820 is attached to the surface of the movable platen 120 facing the fixed platen 110.

[0017] The moving mechanism 102 moves the movable platen 120 forward and backward relative to the fixed platen 110, thereby performing mold closing, pressurization, mold clamping, depressurization, and mold opening of the mold apparatus 800. The moving mechanism 102 has a toggle support 130 arranged at a distance from the fixed platen 110, tie bars 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 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.

[0018] The toggle support 130 is disposed at a distance from the fixed platen 110 and is placed on the mold clamping unit frame 910 so as to be freely movable in the mold opening and closing direction. The toggle support 130 may be disposed so as to be freely movable along a guide laid on the mold clamping unit frame 910. The guide of the toggle support 130 may be the same as the guide 101 of the movable platen 120.

[0019] In the embodiment, the fixed platen 110 is fixed to the mold clamping unit frame 910, and the toggle support 130 is arranged so as to be freely movable in the mold opening / closing direction relative to the mold clamping unit frame 910, but the toggle support 130 may also be fixed to the mold clamping unit frame 910, and the fixed platen 110 may be arranged so as to be freely movable in the mold opening / closing direction relative to the mold clamping unit frame 910.

[0020] The tie bars 140 connect the fixed platen 110 and the toggle support 130 at an interval L in the mold opening / closing direction. A plurality of tie bars 140 (for example, four) may be used. The plurality of tie bars 140 are arranged parallel to the mold opening / closing direction and extend according to the mold clamping force. At least one tie bar 140 may be provided with a tie bar strain detector 141 that detects strain in the tie bar 140. The tie bar strain detector 141 sends a signal indicating the detection result to the control device 700. The detection result of the tie bar strain detector 141 is used to detect the mold clamping force, etc.

[0021] In the embodiment, the tie bar strain detector 141 is used as the mold clamping force detector that detects the mold clamping force, but the present invention is not limited to this. The mold clamping force detector is not limited to the strain gauge type, and may be a piezoelectric type, a capacitance type, a hydraulic type, an electromagnetic type, or the like, and the attachment position thereof is also not limited to the tie bar 140.

[0022] The toggle mechanism 150 is disposed between the movable platen 120 and the toggle support 130, and moves the movable platen 120 in the mold opening / closing direction relative to the toggle support 130. The configuration of this toggle mechanism 150 will be described in detail later.

[0023] The mold clamping motor 160 is attached to the toggle support 130 and operates the toggle mechanism 150. The mold 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 mold clamping motor 160 is directly connected to the motion conversion mechanism 170, but may also be connected to the motion conversion mechanism 170 via a belt, a pulley, or the like.

[0024] The motion conversion mechanism 170 converts the rotational motion of the mold 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.

[0025] The mold clamping unit 100 performs a mold closing process, a pressure increasing process, a mold clamping process, a pressure reducing process, a mold opening process, and the like under the control of the control device 700.

[0026] In the mold closing process, the mold clamping motor 160 is driven to move the crosshead 151 forward at a set movement speed to a mold closing completion position, thereby moving the movable platen 120 forward 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 mold clamping motor encoder 161. The mold clamping motor encoder 161 detects the rotation of the mold clamping motor 160 and sends a signal indicating the detection result to the control device 700.

[0027] The crosshead position detector that detects the position of the crosshead 151 and the crosshead movement speed detector that detects the movement speed of the crosshead 151 are not limited to the mold clamping motor encoder 161, and general types can be used. Furthermore, the movable platen position detector that detects the position of the movable platen 120 and the movable platen movement speed detector that detects the movement speed of the movable platen 120 are not limited to the mold clamping motor encoder 161, and general types can be used.

[0028] In the pressure increasing step, the mold clamping motor 160 is further driven to move the crosshead 151 further forward from the mold closing completion position to the mold clamping position, thereby generating a mold clamping force.

[0029] In the mold clamping process, the mold clamping motor 160 is driven to maintain the position of the crosshead 151 at the mold clamping position. In the mold clamping process, the mold clamping force generated in the pressure increase process is maintained. In the mold clamping process, a cavity space 801 (see FIG. 2) is formed between the movable mold 820 and the fixed mold 810, and the injection device 300 fills the cavity space 801 with liquid molding material. The filled molding material is solidified to obtain a molded product.

[0030] The number of cavity spaces 801 may be one or more. In the latter case, multiple molded products are obtained at the same time. An insert material may be placed in a part of the cavity space 801, and another part of the cavity space 801 may be filled with a molding material. A molded product is obtained in which the insert material and the molding material are integrated.

[0031] In the depressurization process, the mold clamping motor 160 is driven to move the crosshead 151 back from the mold clamping position to the mold opening start position, thereby moving the movable platen 120 back and reducing the mold clamping force. The mold opening start position and the mold closing completion position may be the same position.

[0032] In the mold opening process, the mold clamping motor 160 is driven to move the crosshead 151 backward at a set moving speed from the mold opening start position to the mold opening completion position, thereby moving the movable platen 120 backward and separating the movable mold 820 from the fixed mold 810. Thereafter, the ejector unit 200 ejects the molded product from the movable mold 820.

[0033] The setting conditions for the mold closing process, pressure increase process, and mold clamping process are set together as a series of setting conditions. For example, the movement speed and position of the crosshead 151 in the mold closing process and pressure increase process (including the mold closing start position, movement speed switching position, mold closing completion position, and mold clamping position), and the mold clamping force 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 the rear side to the front, and represent the start and end points of the section for 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 position does not have to be set. Only one of the mold clamping position and the mold clamping force may be set.

[0034] The setting conditions for the depressurization process and mold opening process are also set in a similar manner. For example, the movement speed and position of the crosshead 151 in the depressurization process and 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 the front to the rear, and represent the start and end points of the section for 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 position does not have to be set. The mold opening start position and mold closing completion position may be the same position. Furthermore, the mold opening completion position and mold closing start position may be the same position.

[0035] It should be noted that the moving speed and position of the movable platen 120 may be set instead of the moving speed and position of the crosshead 151. Furthermore, the clamping force may be set instead of the position of the crosshead (e.g., clamping position) or the position of the movable platen.

[0036] When the thickness of the mold device 800 changes due to replacement of the mold device 800 or a temperature change in 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 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.

[0037] The mold clamping unit 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 mold thickness adjustment is performed, for example, between the end of a molding cycle and the start of the next molding cycle. The mold thickness adjustment mechanism 180 has, for example, a screw shaft 181 formed at the rear end of the tie bar 140, a screw nut 182 held rotatably and immovably by the toggle support 130, and a mold thickness adjustment motor 183 that rotates the screw nut 182 that is threaded onto the screw shaft 181.

[0038] A screw shaft 181 and a 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 the plurality of screw nuts 182 via a rotational driving force transmission unit 185. The plurality of screw nuts 182 can be rotated synchronously. Note that by changing the transmission path of the rotational driving force transmission unit 185, the plurality of screw nuts 182 can also be rotated individually.

[0039] The rotational drive force transmission unit 185 is composed of, for example, gears. In this case, a driven gear is formed on the outer periphery 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 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, a pulley, or the like instead of gears.

[0040] The operation of the mold thickness adjustment mechanism 180 is controlled by a control device 700. The control device 700 drives a 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. Note that a plurality of mold thickness adjustment mechanisms may be used in combination.

[0041] The gap L is detected using a 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 of the toggle support 130 and the gap L. Note that the toggle support position detector that detects the position of the toggle support 130 and the gap detector that detects the gap L are not limited to the mold thickness adjustment motor encoder 184, and general detectors can be used.

[0042] The mold clamping unit 100 may have a mold temperature regulator that regulates the temperature of the mold device 800. The mold device 800 has a flow path for a temperature regulation medium inside. The mold temperature regulator regulates the temperature of the mold device 800 by regulating the temperature of the temperature regulation medium supplied to the flow path of the mold device 800.

[0043] The mold clamping unit 100 of the embodiment 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.

[0044] Although the mold clamping unit 100 of the embodiment has a mold clamping motor 160 as a drive unit, it may have a hydraulic cylinder instead of the mold clamping motor 160. Also, the mold clamping unit 100 may have a linear motor for opening and closing the mold, and an electromagnet for mold clamping.

[0045] (Ejector device) In describing the ejector device 200, similar to the description of the mold clamping device 100, the direction of movement of the movable platen 120 when the mold is closed (e.g., the positive direction of the X-axis) is defined as the front, and the direction of movement of the movable platen 120 when the mold is opened (e.g., the negative direction of the X-axis) is defined as the rear.

[0046] The ejector unit 200 is attached to the movable platen 120 and moves forward and backward together with the movable platen 120. The ejector unit 200 has an ejector rod 210 that ejects a molded product from the mold device 800, and a drive mechanism 220 that moves the ejector rod 210 in the movement direction of the movable platen 120 (X-axis direction).

[0047] The ejector rod 210 is arranged so as to be able to move forward and backward in a through-hole of the movable platen 120. The front end of the ejector rod 210 contacts an 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.

[0048] 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 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. Balls or rollers may be interposed between the screw shaft and the screw nut.

[0049] The ejector unit 200 performs an ejection process under the control of the control unit 700. In the ejection process, the ejector rod 210 is advanced from the standby position to the ejection position at a set moving speed, thereby advancing the ejector plate 826 and ejecting the molded product. After that, the ejector motor is driven to retract the ejector rod 210 at the set moving speed, and the ejector plate 826 is retracted to the original standby position.

[0050] The position and movement speed of the ejector rod 210 are detected using, for example, 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 that detects the position of the ejector rod 210 and the ejector rod movement speed detector that detects the movement speed of the ejector rod 210 are not limited to the ejector motor encoder, and general types can be used.

[0051] (injection device) In the description of the injection device 300, unlike the description of the mold clamping device 100 and the description of the ejector device 200, the movement direction of the screw 330 during filling (e.g., the negative X-axis direction) is described as the forward direction, and the movement direction of the screw 330 during metering (e.g., the positive X-axis direction) is described as the rearward direction.

[0052] The injection unit 300 is mounted on a slide base 301, and the slide base 301 is disposed so as to be able to move forward and backward relative to the injection unit frame 920. The injection unit 300 is disposed so as to be able to move forward and backward relative to the mold unit 800. The injection unit 300 touches the mold unit 800 and fills a cavity space 801 in the mold unit 800 with a molding material. The injection unit 300 includes, for example, a cylinder 310 that heats the molding material, a nozzle 320 provided at the front end of the cylinder 310, a screw 330 that is disposed so as to be able to move forward and backward and to be able to rotate within the cylinder 310, a metering motor 340 that rotates the screw 330, an injection motor 350 that moves the screw 330 forward and backward, and a load detector 360 that detects a load transmitted between the injection motor 350 and the screw 330.

[0053] Cylinder 310 heats the molding material supplied to the interior through supply port 311. The molding material includes, for example, resin. The molding material is formed, for example, in the form of pellets and supplied to supply port 311 in a solid state. 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 periphery of the rear of cylinder 310. A first heater 313, such as a band heater, and a first temperature detector 314 are provided on the outer periphery of cylinder 310, ahead of cooler 312.

[0054] Cylinder 310 is divided into a plurality of zones in the axial direction (e.g., X-axis direction) of cylinder 310. A first heater 313 and a first temperature detector 314 are provided in each of the plurality of zones. A set temperature is set in each of the plurality of zones, and control device 700 controls first heater 313 so that the temperature detected by first temperature detector 314 becomes the set temperature.

[0055] The nozzle 320 is provided 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 periphery of the nozzle 320. The control device 700 controls the second heater 323 so that the detected temperature of the nozzle 320 becomes the set temperature.

[0056] The screw 330 is disposed within the cylinder 310 so as to be rotatable and movable forward and backward. When the screw 330 is rotated, the molding material is fed forward along the spiral 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 of the screw 330 and accumulates in the front part of the cylinder 310, the screw 330 is moved backward. When the screw 330 is then moved 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.

[0057] A backflow prevention ring 331 is attached to the front of the screw 330 so as to be movable back and forth as a backflow prevention valve for preventing the molding material from flowing back from the front to the rear of the screw 330 when the screw 330 is pushed forward.

[0058] When the screw 330 is moved forward, the backflow prevention ring 331 is pushed backward by the pressure of the molding material in front of the screw 330, and moves back relative to the screw 330 to a blocking position (see FIG. 2) where it blocks the flow path of the molding material. This prevents the molding material accumulated in front of the screw 330 from flowing backward.

[0059] 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 sent forward along the spiral groove of the screw 330, and moves forward relative to the screw 330 to the open position (see FIG. 1) where it opens the flow path of the molding material. This causes the molding material to be sent forward of the screw 330.

[0060] 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.

[0061] The injection device 300 may have a drive source for moving the backflow prevention ring 331 back and forth relative to the screw 330 between the open position and the closed position.

[0062] The metering motor 340 rotates the screw 330. The drive source for rotating the screw 330 is not limited to the metering motor 340, and may be, for example, a hydraulic pump.

[0063] The injection motor 350 advances and retreats the screw 330. A motion conversion mechanism that converts the rotational motion of the injection motor 350 into linear motion of the screw 330 is provided between the injection motor 350 and the screw 330. The motion conversion mechanism has, for example, a screw shaft and a screw nut that screws onto the screw shaft. A ball or roller may be provided between the screw shaft and the screw nut. The drive source that advances and retreats the screw 330 is not limited to the injection motor 350 and may be, for example, a hydraulic cylinder.

[0064] 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 provided on the load transmission path between the injection motor 350 and the screw 330, and detects the load acting on the load detector 360.

[0065] 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 to control and monitor the pressure that the screw 330 receives from the molding material, the back pressure on the screw 330, the pressure that the screw 330 acts on the molding material, and the like.

[0066] The pressure detector that detects the pressure of the molding material is not limited to the load detector 360, and a general detector can be used. For example, a nozzle pressure sensor or a mold internal pressure sensor may be used. The nozzle pressure sensor is installed in the nozzle 320. The mold internal pressure sensor is installed inside the mold device 800.

[0067] The injection device 300 performs a metering process, a filling process, a pressure holding process, etc. under the control of the control device 700. The filling process and the pressure holding process may be collectively referred to as the injection process.

[0068] 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 sent forward along the spiral groove of the screw 330. As this happens, the molding material gradually melts. As the liquid molding material is sent forward to the screw 330 and accumulates at the front of the cylinder 310, the screw 330 is moved backward. 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 that detects the rotational speed of the screw 330 is not limited to the metering motor encoder 341, and a general one can be used.

[0069] In the metering process, in order to restrict abrupt retraction of the screw 330, the injection motor 350 may be driven to apply a set back pressure to the screw 330. The back pressure on the screw 330 is detected using, for example, a load detector 360. When the screw 330 retracts to the metering completion position and a predetermined amount of molding material accumulates in front of the screw 330, the metering process is completed.

[0070] The position and rotational speed of the screw 330 in the metering process are set together as a series of setting conditions. For example, a metering start position, a rotational speed switching position, and a metering completion position are set. These positions are arranged in this order from the front to the rear, and represent the start and end points of the section for 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 position does not have to be set. In addition, a back pressure is set for each section.

[0071] In the filling process, the injection motor 350 is driven to move the screw 330 forward at a set moving speed, and the liquid molding material accumulated in front of the screw 330 is filled into the cavity space 801 in the mold device 800. The position and moving speed of the screw 330 are detected using, for example, 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 a set position, a switch from the filling process to a pressure holding process (so-called V / P switch) is performed. The position at which the V / P switch is performed is also called the V / P switch position. The set moving speed of the screw 330 may be changed depending on the position of the screw 330, time, etc.

[0072] The position and movement speed of the screw 330 in the filling process are set together as a series of setting conditions. For example, a filling start position (also called an "injection start position"), a movement speed switching position, and a 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 section for 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 position does not have to be set.

[0073] An upper limit value for the pressure of the screw 330 is set for each section in which the movement speed of the screw 330 is set. The pressure of the screw 330 is detected by a load detector 360. When the pressure of the screw 330 is equal to or lower than the set pressure, the screw 330 is advanced at the set movement speed. On the other hand, when the pressure of the screw 330 exceeds the set pressure, the screw 330 is advanced at a movement speed slower than the set movement speed so that the pressure of the screw 330 is equal to or lower than the set pressure, in order to protect the mold.

[0074] It should be noted that after the position of the screw 330 reaches the V / P switching position during the filling process, the screw 330 may be temporarily stopped at the V / P switching position, and then V / P switching may be performed. Immediately before V / P switching, instead of stopping the screw 330, the screw 330 may be moved forward or backward at a slow speed. Furthermore, 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, and general detectors may be used.

[0075] In the dwelling step, 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 can replenish any molding material that is insufficient due to cooling contraction 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 depending on the elapsed time from the start of the dwelling step, etc. Multiple holding pressures and holding times for maintaining the holding pressure in the dwelling step may be set, or they may be set together as a series of setting conditions.

[0076] In the dwelling step, the molding material in the cavity space 801 in the mold device 800 is gradually cooled, and when the dwelling step is completed, the entrance to the cavity space 801 is blocked by the solidified molding material. This state is called a gate seal, and prevents the molding material from flowing back from the cavity space 801. After the dwelling step, the cooling step begins. In the cooling step, the molding material in the cavity space 801 is solidified. A metering step may be performed during the cooling step in order to shorten the molding cycle time.

[0077] Although the injection device 300 in the embodiment is of an in-line screw type, it may also be of a pre-plasticization type. A pre-plasticization type injection device supplies molding material molten in a plasticization cylinder to an injection cylinder, and injects the molding material from the injection cylinder into a mold device. A screw is disposed in the plasticization cylinder so that it can rotate freely but cannot move back and forth, or the screw is disposed so that it can rotate freely and move back and forth. Meanwhile, a plunger is disposed in the injection cylinder so that it can move back and forth.

[0078] Furthermore, although the injection unit 300 of the embodiment is a horizontal type in which the axial direction of the cylinder 310 is horizontal, it may be a vertical type in which the axial direction of the cylinder 310 is vertical. The mold clamping unit combined with the vertical injection unit 300 may be either a vertical type or a horizontal type. Similarly, the mold clamping unit combined with the horizontal injection unit 300 may be either a horizontal type or a vertical type.

[0079] (Mobile device) In the description of the moving device 400, similar to the description of the injection device 300, the moving direction of the screw 330 during filling (e.g., the negative X-axis direction) is defined as the front, and the moving direction of the screw 330 during metering (e.g., the positive X-axis direction) is defined as the rear.

[0080] 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 to generate 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.

[0081] 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 draws in hydraulic fluid (e.g., oil) from one of the first port 411 and the second port 412 and discharges it from the other, thereby generating hydraulic pressure. Note that the hydraulic pump 410 can also draw in hydraulic fluid from a tank and discharge it from either the first port 411 or the second port 412.

[0082] The motor 420 operates the hydraulic pump 410. The motor 420 drives the hydraulic pump 410 in a rotational direction and with a rotational torque according to a control signal from the control device 700. The motor 420 may be an electric motor or an electric servo motor.

[0083] The hydraulic cylinder 430 has 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 interior 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.

[0084] A front chamber 435 of the hydraulic cylinder 430 is connected to a first port 411 of the hydraulic pump 410 via a first flow path 401. The hydraulic fluid discharged from the first port 411 is supplied to the front chamber 435 via the first flow path 401, thereby pushing the injection unit 300 forward. The injection unit 300 is moved forward, and the nozzle 320 is pressed against the fixed mold 810. The front chamber 435 functions as a pressure chamber that generates nozzle touch pressure of the nozzle 320 by the pressure of the hydraulic fluid supplied from the hydraulic pump 410.

[0085] 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 flow path 402. The hydraulic fluid discharged from the second port 412 is supplied to the rear chamber 436 of the hydraulic cylinder 430 via the second flow path 402, thereby pushing the injection unit 300 backward. The injection unit 300 is moved backward, and the nozzle 320 is separated from the fixed mold 810.

[0086] In the embodiment, the moving device 400 includes the hydraulic cylinder 430, but the present invention is not limited to this. 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.

[0087] (Control device) The control device 700 is configured, for example, by a computer, and as shown in Figures 1 and 2, has a CPU (Central Processing Unit) 701, a storage medium 702 such as a memory, an input interface 703, and an output interface 704. The control device 700 performs various controls by causing the CPU 701 to execute a program stored in the storage medium 702. The control device 700 also receives signals from the outside via the input interface 703 and transmits signals to the outside via the output interface 704.

[0088] The control device 700 repeatedly manufactures molded products by repeating processes such as a metering process, mold closing process, pressure increase process, mold clamping process, filling process, pressure dwell process, cooling process, pressure release process, mold opening process, and ejection process (see also FIG. 4). A series of operations required to obtain a molded product, for example, the operations from the start of a 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."

[0089] One molding cycle includes, for example, a metering process, a mold closing process, a pressurization process, a mold clamping process, a filling process, a pressure holding process, a cooling process, a depressurization process, a mold opening process, and an ejection process, in this order. The order here refers to the order in which each process starts. The filling process, the pressure holding process, and the cooling process are performed during the mold clamping process. The start of the mold clamping process may coincide with the start of the filling process. The completion of the depressurization process coincides with the start of the mold opening process.

[0090] It should be noted that, in order to shorten the molding cycle time, multiple processes may be performed simultaneously. 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 be started during the mold closing process. The ejection process may be started during the mold opening process. If an on-off valve for opening and closing the flow path of the nozzle 320 is provided, 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, the molding material will not leak from the nozzle 320 as long as the on-off valve closes the flow path of the nozzle 320.

[0091] One molding cycle may include steps other than the metering step, mold closing step, pressure increase step, mold clamping step, filling step, pressure holding step, cooling step, pressure release step, mold opening step, and ejection step.

[0092] For example, after the dwelling step is completed and before the metering step begins, a pre-metering suck-back step may be performed in which the screw 330 is retracted to a preset metering start position. This can reduce the pressure of the molding material accumulated in front of the screw 330 before the metering step begins, and prevent the screw 330 from retracting suddenly at the start of the metering step.

[0093] Furthermore, after the metering step is completed and before the filling step begins, a post-metering suck-back step may be performed in which the screw 330 is retracted to a preset filling start position (also referred to as the "injection start position"). This can reduce the pressure of the molding material accumulated in front of the screw 330 before the filling step begins, and can prevent the molding material from leaking from the nozzle 320 before the filling step begins.

[0094] The control device 700 is connected to an operation device 750 that accepts input operations by a user and a display device 760 that displays a screen. The operation device 750 and the display device 760 may be integrated, for example, by using a touch panel 770. The touch panel 770 serving 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 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 units such as buttons and input fields that accept input operations by the user. The touch panel 770 serving as the operation device 750 detects input operations on the screen by the user and outputs signals corresponding to the input operations to the control device 700. This allows, for example, a user to operate the operation units provided on the screen while checking information displayed on the screen to perform settings of the injection molding machine 10 (including input of setting values). The user can also operate the operation units provided on the screen to cause the injection molding machine 10 to perform operations corresponding to the operation units. The operation of the injection molding machine 10 may be, for example, the operation (including stopping) of the clamping device 100, the ejector device 200, the injection device 300, the moving device 400, etc. The operation of the injection molding machine 10 may also be the switching of a screen displayed on the touch panel 770 serving as the display device 760, etc.

[0095] Although the operation device 750 and the display device 760 in the embodiment have been described as being integrated as the touch panel 770, they may be provided independently. Also, a plurality of operation devices 750 may be provided. The operation device 750 and the display device 760 are disposed on the operation side (negative Y-axis direction) of the mold clamping unit 100 (more specifically, the fixed platen 110).

[0096] (Details of the control device) Next, an example of the components of the control device 700 will be described with reference to FIG. 3. Note that each functional block shown in FIG. 3 is conceptual and does not necessarily have to be physically configured as shown. All or part of each functional block can be configured by functionally or physically distributing or integrating in any unit. All or any part of the processing functions performed by each functional block can be realized by a program executed by a CPU, or can be realized as hardware using wired logic.

[0097] As shown in FIG. 3, the control device 700 includes, for example, a mold clamping control unit 711, an ejector control unit 712, an injection control unit 713, a measurement control unit 714, a display control unit 715, and an input acquisition unit 716. The mold clamping control unit 711 controls the mold clamping unit 100 and performs the mold closing process, pressurization process, mold clamping process, depressurization process, and mold opening process shown in FIG. 4. The ejector control unit 712 controls the ejector unit 200 and performs the ejection process. The injection control unit 713 controls the injection drive source of the injection unit 300 and performs the injection process. The injection drive source is, for example, the injection motor 350, but may also be a hydraulic cylinder or the like. The injection process includes a filling process and a pressure holding process. The injection process is performed during the mold clamping process. The measurement control unit 714 controls the measurement drive source of the injection unit 300 and performs the measurement process. The metering drive source is, for example, a metering motor 340, but may also be a hydraulic pump, etc. The metering step is performed during the cooling step.

[0098] The filling process is a process of controlling the injection drive source so that the actual value of the moving speed of the injection member provided inside the cylinder 310 becomes a set value. The filling process is a process of moving the injection member forward to fill the interior of the mold device 800 with liquid molding material (e.g., resin) accumulated in front of the injection member. The injection member is, for example, the screw 330, but may also be a plunger.

[0099] The moving speed of the injection member is detected using a speed detector, such as the injection motor encoder 351. In the filling step, the pressure acting on the molding material from the injection member increases as the injection member moves forward. The filling step may include a step of temporarily stopping the injection member or a step of retracting the injection member immediately before the pressure holding step.

[0100] The pressure holding process is a process of controlling the injection drive source so that the actual value of the pressure acting on the molding material from the injection member becomes a set value. The pressure holding process is a process of pushing the injection member forward to replenish the molding material that is insufficient due to cooling contraction within the mold device 800. The pressure is detected using a pressure detector such as the load detector 360. A nozzle pressure sensor or a mold internal pressure sensor may be used as the pressure detector.

[0101] Furthermore, before the start of injection molding, at each step during injection molding, and after the end of injection molding, the display control unit 715 of the control device 700 transmits display screen information relating to injection molding and causes it to be displayed on the display device 760. A plurality of display screens are prepared, and the display control unit 715 is capable of switching between the screens and displaying the screens in an overlapping manner.

[0102] Furthermore, the input acquisition unit 716 of the control device 700 acquires information on the operation content when the user operates the operation device 750 based on the display screen displayed on the display device 760. For example, when the setting content of the injection molding is changed by the user, the input acquisition unit 716 stores the setting content in the storage medium 702.

[0103] (cleaning process) In the injection molding machine 10 described above, during injection molding, debris (such as resin mold deposits, gas deposits, and tar) may occur at the interface between the fixed mold 810 and the movable mold 820 of the mold device 800. Conventionally, to remove such debris in injection molding machines, an operator performs cleaning work, such as wiping the interface between the molds with a rag soaked in a cleaning agent such as alcohol. This cleaning work is performed after a set number of injection molding cycles have been performed or after a set period of injection molding has elapsed. For example, cleaning work is performed approximately once a day. This cleaning work causes inconveniences, such as an increased burden on the operator and a decrease in the production efficiency of molded products.

[0104] Therefore, the injection molding machine 10 according to the embodiment is configured to deliberately mold a molded product that has flash leaking between the fixed mold 810 and the movable mold 820, and then perform a cleaning process to absorb the debris on the interface between the molds (the fixed mold 810 and the movable mold 820). The injection molding machine 10 automatically performs a cleaning process after, for example, a set number of injection moldings to remove the debris on the interface between the molds. This allows the injection molding machine 10 to reduce the number of cleaning operations required by the worker, reducing the burden on the worker and improving manufacturing efficiency.

[0105] The injection molding machine 10 may be configured to perform the cleaning process only once between injection molding cycles, or may be configured to perform the cleaning process multiple times between injection molding cycles. For example, the injection molding machine 10 may change the number of cleaning processes in conjunction with the number of normal injection molding cycles. Also, for example, the injection molding machine 10 may be configured to perform the cleaning process at the end of an operation in which injection molding cycles are continuously repeated.

[0106] As shown in Figures 5(A) to 5(C), the injection molding machine 10 performs control during the cleaning process to separate the fixed mold 810 and the movable mold 820 to create a gap sufficient to prevent flash from forming at the boundary between the molds. For example, the control device 700 operates the mold thickness adjustment mechanism 180 to adjust (lengthen) the distance L between the fixed platen 110 and the toggle support 130, thereby creating a gap between the fixed platen 110 and the movable platen 120 during injection molding. This mold thickness adjustment enables the injection molding machine 10, when performing the mold closing process, to position the movable mold 820 at a flash molding position that is farther away from the fixed mold 810 than the mold clamping position during normal injection molding.

[0107] The upper diagram in FIG. 5(C) shows the burr formation position when the molds are closed during the cleaning process, and the lower diagram in FIG. 5(C) shows the mold clamping position when the molds are clamped during normal injection molding for comparison. The burr formation position is located on the negative side of the X-axis relative to the mold clamping position. For example, although the burr formation position depends on factors such as the fluidity of the molding material, it can be set at a position where the gap at the interface between the molds is approximately 0.5 mm to 2 mm. This burr formation position is set in advance through experiments, simulations, etc., and is stored in the control device 700 together with the interval for the cleaning process. Alternatively, the burr formation position may be set arbitrarily based on the operator's operation of the operating device 750.

[0108] In addition, during the cleaning process, the injection molding machine 10 may perform control to reduce the clamping force while maintaining mold contact (contact) without completely separating the fixed mold 810 and the movable mold 820. In other words, the burr molding position may be set as close as possible to the clamping position. However, when the clamping force is reduced, the force that the toggle mechanism 150 can withstand changes depending on the amount by which the movable mold 820 opens from the fixed mold 810. Therefore, depending on the pressure from the molding material, the movable platen 120 may not be stopped at the desired position. Therefore, it is more desirable for the injection molding machine 10 to perform the cleaning process by controlling the clamping force to zero by setting the burr molding position so that a gap is created between the fixed mold 810 and the movable mold 820.

[0109] When the injection device 300 injects molding material into the mold device 800 with the movable mold 820 moved to the burr molding position, the molding material leaks from the cavity space 801 to the interface between the molds. The leaked molding material absorbs dust and turns into burrs upon cooling. Therefore, by deliberately molding a molded product with burrs, the injection molding machine 10 can remove dust from the interface between the fixed mold 810 and the movable mold 820.

[0110] However, the injection molding machine 10 must not move (retract) the movable mold 820, which is positioned at the burr-forming position, in the negative direction of the X axis during the cleaning process. If the toggle mechanism 150 is bent significantly at the burr-forming position and injection is performed into the mold device 800 in this state, it is expected that the burr-forming position cannot be maintained and the burr will become very large. In this case, the injection molding machine 10 will not be able to remove the molded product having the burr from the movable mold 820. Therefore, the injection molding machine 10 according to the embodiment adjusts the mold thickness using the mold thickness adjustment mechanism 180, thereby setting a range in which the thrust of the crosshead 151 (the force generated by the ball screw and motor, or the force generated by a linear actuator such as a hydraulic cylinder) is amplified by the toggle mechanism 150.

[0111] The region amplified by the toggle mechanism 150 is a region where the toggle ratio is 1 or more. In other words, the injection molding machine 10 adjusts the mold thickness by the mold thickness adjustment mechanism 180 so that the toggle ratio of the toggle mechanism 150 is 1 or more at the flash molding position. The toggle mechanism 150 has a toggle ratio of less than 1 for most of its mold opening and closing stroke, and although it depends on the design of the toggle mechanism 150, the region amplified by the toggle mechanism 150 (the range where the toggle ratio is 1 or more) is about 10% of the mold opening and closing stroke.

[0112] However, it is more preferable that the toggle mechanism 150 has a toggle magnification of 5 to 10 or more. By setting the toggle magnification to 5 to 10 or more, it is possible to more reliably prevent the movable platen 120 and the movable mold 820 from shifting positions during the cleaning process. Next, the toggle magnification of the toggle mechanism 150 will be described with reference to FIG. 6.

[0113] As shown in FIG. 6 , the toggle mechanism 150 has a crosshead 151 that moves in the mold opening / closing direction, and a pair of link groups that bend and stretch with the movement of the crosshead 151. Each of the pair of link groups includes a first link 152, a second link 153, and a third link 154. One end of the first link 152 is swingably attached to the movable platen 120 by a first pin 155. One end of the second link 153 is swingably attached to the other end of the first link 152 by a second pin 156. The other end of the second link 153 is swingably attached to the toggle support 130 by a third pin 157. One end of the third link 154 is swingably attached to an intermediate position and inside of the second link 153 by a fourth pin 158. The other end of the third link 154 is attached to a protrusion provided on the outer surface of the crosshead 151 by a fifth pin 159 so as to be able to swing freely.

[0114] In the link group configured in this manner, when the crosshead 151 is advanced in the positive direction of the X axis, the third link 154 moves the intermediate position of the second link 153 in the opening direction. As one end of the second link 153 moves in the positive direction of the X axis, the connecting portion (second pin 156) with the first link 152 extends, pushing the first link 152 in the positive direction of the X axis. This advancement of the first link 152 advances the movable platen 120 in the positive direction of the X axis. On the other hand, when the crosshead 151 is retracted in the negative direction of the X axis, the link group performs the reverse operation to that described above, thereby retracting the movable platen 120 in the negative direction of the X axis.

[0115] The toggle mechanism 150 can amplify the driving force of the mold clamping motor 160 and transmit it to the movable platen 120. The amplification factor by the toggle mechanism 150 is called a toggle factor. The toggle factor α can be calculated by the following formula (1). M=α·F Toggle magnification α=M / F …(1)

[0116] The toggle magnification factor α corresponds to the coefficient portion of the force F applied from the crosshead 151 in equation (1). A force M obtained by multiplying the force F of the crosshead 151 by the toggle magnification factor α can be applied to the movable platen 120. In other words, if the toggle magnification factor α is 1 or greater, a force M greater than or equal to the force F of the crosshead 151 will be applied to the movable platen 120. Here, the force M obtained by multiplying the force F of the crosshead 151 by the toggle magnification factor α can be measured using a detector such as a strain sensor. The toggle magnification factor α can be changed by changing the arrangement of the pins 156 to 159 and changing the angle at which the lines connecting the pins intersect.

[0117] As described above, the toggle mechanism 150 amplifies the driving force of the mold clamping motor 160 from the crosshead 151 in accordance with the toggle ratio α and transmits it to the movable platen 120. If the toggle ratio α is 1 or greater, the toggle mechanism 150 can obtain a fixing force that prevents the movable platen 120 and the movable mold 820 from retracting, even when the injection unit 300 injects molding material into the mold unit 800. In other words, the mold clamping unit 100 using the toggle mechanism 150 can easily eliminate the problem of the movable platen 120 opening due to inability to withstand the filling pressure. In particular, mold thickness adjustment by the mold thickness adjustment mechanism 180 provides the advantage that the injection molding machine 10 can use a position with a high toggle ratio α, so the toggle ratio α is usually increased at the molding position. However, a high toggle ratio α also has the disadvantage of placing a heavy load on each part.

[0118] Furthermore, when the movable mold 820 is moved in a direction away from the fixed mold 810, the toggle ratio α generally decreases, and when the movable mold 820 is moved closer to the fixed mold 810, the toggle ratio α increases. If the toggle ratio α is set high at a position where the movable mold 820 is away from the fixed mold 810 and where the toggle ratio α is not required, the toggle ratio α at the mold clamping position becomes high, and the mold clamping force may become too high. For this reason, the toggle ratio α is set to less than 1 at a position where the movable mold 820 is away from the fixed mold 810.

[0119] However, in this embodiment, the arrangement of the pins 156 to 159 is designed so that the toggle magnification α is 1 or more at the flash forming position even when the movable mold 820 is located away from the fixed mold 810.

[0120] The configuration of the toggle mechanism 150 is not limited to the configuration shown in Fig. 6. For example, although each link group has five nodes in Fig. 6, it may have four nodes, and one end of the third link 154 may be connected to the node between the first link 152 and the second link 153.

[0121] 3, in order to perform normal injection molding and cleaning processing, the control device 700 includes a main control unit 711a, a cleaning control unit 711b, and a switching determination unit 711c inside the clamping control unit 711. Based on the processing of each functional unit of the clamping control unit 711, the injection molding machine 10 can control the operation of the clamping unit 100 in normal injection molding and cleaning processing.

[0122] Specifically, the main control unit 711a is a functional unit that controls normal injection molding. The main control unit 711a controls the operations of the mold clamping unit 100 for injection molding (mold closing process, pressure increase process, mold clamping process, depressurization process, mold opening process, etc.) (see also FIG. 4(A)). For example, the main control unit 711a controls the mold clamping motor 160 to move the movable platen 120 and the movable mold 820 to positions set in each process (mold closing start position, movement speed switching position, mold closing completion position, mold clamping position, etc.). At this time, the main control unit 711a also controls the mold clamping motor 160 using detection information from the mold clamping motor encoder 161 to adjust the position of the movable mold 820.

[0123] The cleaning control unit 711b is a functional unit that controls the cleaning process. When switching from injection molding to cleaning process, the cleaning control unit 711b controls the operation of the mold thickness adjustment mechanism 180 of the mold clamping unit 100 to switch the positions of the movable platen 120 and the movable mold 820 to a position for the cleaning process. The position for the cleaning process is a position where the movable platen 120 and the movable mold 820 are located at the flash molding position during the mold closing process, as described above.

[0124] After this mold thickness adjustment, the cleaning control unit 711b controls the operations of the mold clamping unit 100 in the cleaning process (mold closing process, position maintaining process, mold closing process) (see also FIG. 4(B)). The mold closing process in the cleaning process is a process of moving the movable platen 120 and the movable mold 820 to the burr forming position. The position maintaining process in the cleaning process is a process of maintaining the burr forming position of the movable mold 820 and causing the injection unit 300 to execute the injection process (filling process, pressure holding process) and the cooling process during this period. The mold opening process in the cleaning process is a process of moving the movable platen 120 and the movable mold 820 back from the burr forming position. Note that, when the fixed mold 810 and the movable mold 820 are brought into contact with each other in the cleaning process while the clamping force between the molds is reduced, the cleaning control unit 711b may perform a pressure increase process between the mold closing process and the position maintaining process, and a pressure release process between the position maintaining process and the mold opening process.

[0125] The switching determination unit 711c determines whether to switch from normal injection molding to cleaning processing, and whether to switch from cleaning processing to normal injection molding. For example, the switching determination unit 711c has a threshold value for determining whether to start cleaning processing, counts the actual number of injection moldings, and determines whether to start cleaning processing when this actual number is equal to or greater than the threshold value for determining whether to start cleaning processing. The same applies when returning from cleaning processing to injection molding. Alternatively, the switching determination unit 711c may notify whether or not cleaning processing can be performed via the display device 760 or the like, and determine whether to start cleaning processing under the operator's instructions.

[0126] The injection molding machine 10 according to the embodiment is basically configured as described above, and an example of the cleaning process will be described below with reference to FIGS.

[0127] The control device 700 of the injection molding machine 10 sequentially executes steps S101 to S114 in FIGS. 7 and 8 as an operating method for the cleaning process.

[0128] Specifically, the switching determination unit 711c of the control device 700 determines whether or not to execute cleaning processing when normal injection molding is being performed by the main control unit 711a (step S101). For example, the switching determination unit 711c increments the actual number of injection moldings as the mold closing process by the mold clamping unit 100 starts and compares the incremented number with a start determination threshold, thereby determining whether or not to switch to cleaning processing after this injection molding. If the control device 700 determines that cleaning processing should be executed (step S101: YES), it proceeds to step S102, and if the control device 700 determines that cleaning processing should not be executed (step S101: NO), it repeats step S101.

[0129] Then, while normal injection molding is being performed, the control device 700 prepares to perform the next cleaning process. Specifically, as normal injection molding, the control device 700 performs the injection process (filling process, pressure holding process) by the injection unit 300 while performing the pressure increase process and mold clamping process by the mold clamping unit 100 (step S102).

[0130] Then, while the cooling process after the injection process is being performed, the measurement control unit 714 of the control device 700 performs a measurement process corresponding to the next cleaning process, and measures out the molding material in an amount necessary to form flash in this measurement process (step S103). The amount of molding material necessary to form flash depends on the shape of the molded product and the molding conditions, but may be, for example, an amount that is increased by about 1% to 10% compared to the amount of molding material used in normal injection molding. Alternatively, the amount of molding material need not change between normal injection molding and the cleaning process.

[0131] After the cooling process, the control device 700 controls the mold clamping device 100 to perform the normal injection molding depressurization process and mold opening process, and also controls the ejector device 200 to perform the molded product ejection process (step S104). However, after ejecting the molded product, the control device 700 may stop the ejector rod 210 at a mid-return position rather than retracting it to its return limit. By stopping the ejector rod 210 at a mid-return position, a gap can be formed in the part that the ejector rod 210 pushes when a cleaning process is performed, which can facilitate the release of a molded product that has burrs. In this case, the part that the ejector rod 210 pushes should preferably be the part with the burrs.

[0132] When the ejector unit 200 moves backward, the molding cycle of the normal injection molding ends. Therefore, the control device 700 moves to a molding cycle in which a cleaning process is performed. In this case, the cleaning control unit 711b of the control device 700 operates the mold thickness adjustment mechanism 180 to perform mold thickness adjustment, which retracts the movable platen 120 and the movable mold 820 to a position for the cleaning process, as a preliminary preparation for the cleaning process (step S105). For example, the cleaning control unit 711b operates the mold thickness adjustment mechanism 180 so that the movable mold 820 is spaced 1.5 mm from the fixed mold 810 during the mold closing step of the cleaning process.

[0133] When the mold thickness adjustment by the mold thickness adjustment mechanism 180 is completed, the cleaning control unit 711b executes a molding cycle of the cleaning process. As shown in Fig. 8, in the cleaning process, the cleaning control unit 711b first controls the mold clamping unit 100 to move the movable platen 120 and the movable mold 820 in the positive direction of the X-axis to perform the mold closing process (step S106). As a result, the movable platen 120 and the movable mold 820 are positioned close to the fixed mold 810 at a burr molding position (see also Fig. 5(C)). The burr molding position is, for example, a position where a gap of 1.5 mm is provided between the boundary surfaces of the fixed mold 810 and the movable mold 820.

[0134] The cleaning control unit 711b then controls the mold clamping unit 100 to perform the position maintaining step, and the injection control unit 713 controls the injection unit 300 to perform the injection step (filling step, pressure holding step) (step S107). In this position maintaining step, the cleaning control unit 711b drives the mold clamping motor 160 to maintain the toggle magnification α of the toggle mechanism 150 at 1 or more without changing the flash molding position. This prevents the movable platen 120 and the movable mold 820 from moving backward (shifting in position) even when molding material is filled from the injection unit 300 into the mold unit 800 in the injection step.

[0135] After the injection step, the control device 700 shifts to the cooling step, and completes the molding of the molded product having flash (step S108). The flash contains dust particles from the boundary between the molds.

[0136] Furthermore, the control device 700 performs a mold opening process, retracts the movable mold 820 from the fixed mold 810, and controls the ejector device 200 to perform a molded product ejection process (step S109). As a result, the molded product having burrs is removed from the movable mold 820, and waste at the boundary between the molds is removed. The molded product having burrs is removed and discarded, for example, by an automatic sorting machine or an operator. Note that the operator may also perform an operation to remove the burrs from the molded product having burrs.

[0137] Furthermore, the switching determination unit 711c determines whether or not to return to normal injection molding during this cleaning process (step S110). For example, the switching determination unit 711c monitors whether the cleaning process has been performed a set number of times, and determines to return to injection molding if the cleaning process has been performed the set number of times, while determining to repeat the cleaning process if the cleaning process has not been performed the set number of times. Note that while FIG. 8 shows this return determination as occurring after the ejection process, the return determination may be performed in parallel with the injection process of the cleaning process, and is preferably performed at least before the cooling retraction of the cleaning process. This allows the molding material to be measured appropriately in accordance with the next injection molding in the measurement process performed during the cooling process.

[0138] If normal injection molding is to be resumed (step S110: YES), the process proceeds to step S111, where the molding material for injection molding is measured. After the ejection process, the control device 700 switches to a molding cycle that next performs normal injection molding. In this case, the main control unit 711a of the control device 700 operates the mold thickness adjustment mechanism 180 to advance the movable platen 120 and movable mold 820 to positions for injection molding in preparation for the remaining time for normal injection molding (step S112).

[0139] Then, after step S112, the injection molding machine 10 starts normal injection molding again (step S113). Because the movable platen 120 and the movable mold 820 have returned to their original positions by the mold thickness adjustment in advance, the main control unit 711a can operate the mold clamping unit 100 to stably perform the mold closing process, pressure increase process, mold clamping process, depressurization process, mold opening process, etc.

[0140] On the other hand, if the cleaning process is to be repeated (step S110: NO), the process proceeds to step S114, where the molding material for the cleaning process is measured. After the ejection step, the control device 700 returns to step S106, and performs the cleaning process again.

[0141] As described above, the injection molding machine 10 according to the embodiment can mold a molded product having burrs by simply adjusting the position of the movable mold 820 under the control of the control device 700, thereby efficiently cleaning the interface between the molds. Furthermore, the movable platen 120 and the movable mold 820 positioned at the burr molding position can stably maintain the burr molding position because the toggle ratio α of the toggle mechanism 150 is set to 1 or greater. This allows the shape (size, etc.) of the burr to be appropriately adjusted and debris to be removed. As a result, the injection molding machine 10 reduces the number of times an operator must clean the mold assembly 800, thereby reducing the burden on the operator and improving the overall manufacturing efficiency of molded products. For example, the injection molding machine 10 can reduce the cleaning work that was previously performed by an operator once a day to once every several days (e.g., seven days).

[0142] In particular, in the cleaning process, the injection molding machine 10 forms a gap between the movable mold 820 that has been moved to the burr forming position and the fixed mold 810, thereby enabling burrs of a set size to be stably formed.

[0143] Furthermore, before performing the cleaning process, the injection molding machine 10 operates the mold thickness adjustment mechanism 180 to adjust the distance between the fixed platen 110 and the movable platen 120 to the distance for the cleaning process. This makes it possible for the injection molding machine 10 to stably maintain the toggle ratio α at a high ratio even when the movable platen 120 and the movable mold 820 are positioned at the flash molding position during the cleaning process.

[0144] Furthermore, after the cleaning process is completed, the injection molding machine 10 adjusts the distance between the fixed platen 110 and the movable platen 120 to the distance for injection molding and returns to injection molding, thereby allowing injection molding to be smoothly resumed after the cleaning process.

[0145] Furthermore, by repeating the cleaning process multiple times, the injection molding machine 10 can sufficiently remove dust generated on the boundary surface between the fixed mold 810 and the movable mold 820.

[0146] Furthermore, the injection molding machine 10 can measure an appropriate amount of molding material in the measuring process by determining the start and / or end of the cleaning process before the measuring process of the injection unit 300. This allows the control unit 700 to more smoothly switch between normal injection molding and the cleaning process.

[0147] Furthermore, by setting the toggle magnification α at the burr forming position to 5 times or more, the toggle mechanism 150 can more reliably prevent the movable platen 120, which has moved to the burr forming position, from shifting in position.

[0148] The injection molding machine 10 according to the embodiment is not limited to the above embodiment and may take various modified forms. For example, the toggle ratio α of the toggle mechanism 150 of the injection molding machine 10 when positioned at the flash molding position may be 1 or greater, and the method of adjusting the positions of the movable platen 120 and the movable mold 820 is not limited to the mold thickness adjustment by the mold thickness adjustment mechanism 180. For example, the injection molding machine 10 may position the movable platen 120 and the movable mold 820 at the flash molding position by controlling the mold clamping motor 160 without adjusting the mold thickness. Even in this case, as long as the toggle ratio α is 1 or greater, retraction of the movable platen 120 and the movable mold 820 can be suppressed.

[0149] Furthermore, for example, the injection molding machine 10 may employ a method in which filling begins with a wide gap as in compression molding, and after filling, the movable platen 120 and movable mold 820 are moved to crush the molded product and form a burr. In this case, even if the movable platen 120 and movable mold 820 are positioned at the burr forming position, the pressure of the molding material is reduced, and further, by moving the movable platen 120, the toggle magnification α can be increased while forming a burr.

[0150] The injection molding machine 10 according to the presently disclosed embodiment is illustrative in all respects and not restrictive. The embodiment may be modified and improved in various ways without departing from the spirit and scope of the appended claims. The features described in the above-described embodiments may be configured differently and may be combined within a consistent range. [Explanation of symbols]

[0151] 10 injection molding machine 100 Mold clamping device 110 Fixed Platen 120 Movable Platen 150 Toggle Mechanism 180 Type thickness adjustment mechanism 300 Injection device 700 control device 810 Fixed mold 820 Movable mold

Claims

1. a mold clamping device including a movable platen having a movable mold, a fixed platen having a fixed mold facing the movable mold, and a toggle mechanism that moves the movable platen relative to the fixed platen in a mold opening / closing direction and can position the movable platen at a mold clamping position; an injection device that injects a molding material into a cavity space formed by the movable mold and the fixed mold disposed at the mold clamping position; a control device that controls operations of the injection device and the mold clamping device, the control device performs a cleaning process to form a molded product having a burr by injecting the molding material using the injection device in a state in which the movable platen is moved to a burr forming position where the movable mold is spaced apart from the fixed mold with respect to the mold clamping position; the toggle mechanism has a toggle magnification of 1 or more at the burr forming position; Injection molding machine.

2. the control device forms a gap between the movable mold moved to the burr forming position and the fixed mold in the cleaning process.

2. The injection molding machine according to claim 1.

3. the mold clamping device has a mold thickness adjustment mechanism that adjusts the gap between the fixed platen and the movable platen, the control device operates the mold thickness adjustment mechanism to adjust the gap between the fixed platen and the movable platen to a gap for the cleaning process before performing the cleaning process; 3. The injection molding machine according to claim 2.

4. After the cleaning process is completed, the control device adjusts the gap between the fixed platen and the movable platen to a gap for injection molding, and returns to injection molding.

4. The injection molding machine according to claim 3.

5. The control device repeats the cleaning process multiple times.

5. The injection molding machine according to claim 1.

6. the control device determines the start and / or end of the cleaning process before the measurement process of the injection device; In the measuring step, the amount of the molding material is measured according to the determined result.

6. The injection molding machine according to claim 5.

7. The toggle mechanism has a toggle magnification of 5 times or more at the burr forming position.

5. The injection molding machine according to claim 1.

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