Control device of injection molding machine and control method of injection molding machine

Abstract

The present invention relates to a control device of an injection molding machine and a control method of an injection molding machine, and provides a technique for supporting temperature setting of at least one of a nozzle and a cylinder. The control device of the injection molding machine has a monitoring section that monitors a change in a filling pressure acting on a molding material in the middle of a filling process of filling the molding material into an inside of a mold device.

Description

Technical Field

[0001] This application claims priority based on Japanese Patent Application No. 2021-196977, filed on December 3, 2021. The entire contents of that Japanese application are incorporated herein by reference.

[0002] This invention relates to a control device and a control method for an injection molding machine. Background Technology

[0003] Patent Document 1 describes an injection molding machine comprising a mold and an injection device. The mold has a moving mold and a fixed mold, which form a cavity. The injection device includes a heating cylinder and a screw disposed within the heating cylinder. By advancing the screw, molten resin in the heating cylinder fills the cavity. In Patent Document 1, an vent is provided in the mold to facilitate the discharge of air from the cavity and gases generated by the molten resin to the outside of the mold, and the screw is temporarily stopped midway through at least one of the filling and holding pressure processes.

[0004] Patent Document 1: Japanese Patent Application Publication No. 08-164545

[0005] An injection molding machine includes a cylinder for heating the molding material and a nozzle located at the front end of the cylinder for injecting the heated molding material into the mold assembly. If the temperature of at least one of the nozzle or the cylinder is too low, nozzle blockage will occur. Nozzle blockage is a phenomenon where the molding material M is not injected from the nozzle even when the screw advances and the filling process begins. On the other hand, if the temperature of at least one of the nozzle or the cylinder is too high, drooling will occur. Drooling is a phenomenon where the nozzle drips molding material into the mold assembly before the filling process begins.

[0006] It is difficult to determine whether nozzle blockage or drooling has occurred during the quality inspection of molded products. In the past, skilled workers set the nozzle and cylinder temperatures based on their own experience, while it was more difficult for non-skilled workers to set the nozzle and cylinder temperatures. Summary of the Invention

[0007] One aspect of the present invention provides a technique for supporting temperature setting of at least one of the nozzle and cylinder.

[0008] One aspect of the present invention relates to a control device for an injection molding machine having a monitoring unit that monitors changes in the filling pressure acting on the molding material during a filling process of filling the molding material into the mold assembly.

[0009] The effects of the invention

[0010] According to one aspect of the invention, by monitoring changes in filling pressure during the filling process, it is possible to determine whether nozzle blockage or drooling has occurred. As a result, it is possible to support temperature settings for at least one of the nozzle and the cylinder. Attached Figure Description

[0011] Figure 1 This is a diagram showing the state of the injection molding machine at the end of mold opening according to one embodiment.

[0012] Figure 2 This is a diagram showing the state of the injection molding machine during mold closing according to one embodiment.

[0013] Figure 3 This is a diagram illustrating an example of how function blocks represent the components of a control device.

[0014] Figure 4 This is a diagram illustrating an example of a process in the molding cycle.

[0015] Figure 5 This is a cross-sectional view showing an example of molding material flowing into the mold assembly.

[0016] Figure 6 This is the first example of a graph showing the change in the actual value of the filling pressure.

[0017] Figure 7 This is the second example of a graph showing the change in the actual value of the filling pressure.

[0018] Symbol Explanation

[0019] 10-Injection molding machine, 310-Cylinder, 320-Nozzle, 700-Control device, 717-Monitoring unit, 800-Mold device. Detailed Implementation

[0020] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, in the drawings, the same or corresponding structures are sometimes labeled with the same symbols, and descriptions are omitted.

[0021] (Injection molding machine)

[0022] Figure 1 This is a diagram showing the state of the injection molding machine at the end of mold opening according to one embodiment. Figure 2This diagram illustrates the mold-closing state of the injection molding machine according to one embodiment. In this specification, the X-axis, Y-axis, and Z-axis are mutually perpendicular directions. The X-axis and Y-axis represent horizontal directions, and the Z-axis represents vertical directions. When the mold-closing device 100 is horizontal, the X-axis represents the mold opening and closing direction, and the Y-axis represents the width direction of the injection molding machine 10. The negative side of the Y-axis is referred to as the operating side, and the positive side of the Y-axis is referred to as the opposite side of the operating side.

[0023] like Figures 1-2 As shown, the injection molding machine 10 includes: a mold clamping device 100, a mold opening and closing device 800; an ejection device 200 for ejecting the molded article formed by 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 mold clamping device frame 910 for supporting the mold clamping device 100; and an injection device frame 920 for supporting the injection device 300. The mold clamping device frame 910 and the injection device frame 920 are respectively mounted on the base plate 2 via horizontal adjusting casters 930. The control device 700 is arranged in the internal space of the injection device frame 920. The components of the injection molding machine 10 will be described below.

[0024] (Mold closing device)

[0025] In the description of the mold closing device 100, the moving direction of the movable pressure plate 120 when the mold is closed (e.g., the positive X-axis direction) is set to forward, and the moving direction of the movable pressure plate 120 when the mold is opened (e.g., the negative X-axis direction) is set to rearward.

[0026] The mold closing device 100 performs mold closing, pressurization, mold closing, depressurization, and mold opening of the mold device 800. The mold device 800 includes a fixed mold 810 and a moving mold 820.

[0027] The mold closing device 100 is, for example, horizontal, and the mold opening and closing direction is horizontal. The mold closing device 100 has a fixed pressure plate 110 for mounting the fixed mold 810, a movable pressure plate 120 for mounting the moving mold 820, and a moving mechanism 102 for moving the movable pressure plate 120 relative to the fixed pressure plate 110 in the mold opening and closing direction.

[0028] The fixed pressure plate 110 is fixed relative to the mold closing device frame 910. The fixed mold 810 is installed on the surface of the fixed pressure plate 110 opposite to the movable pressure plate 120.

[0029] The movable pressure plate 120 is configured to move freely relative to the mold clamping device frame 910 in the mold opening and closing direction. A guide member 101 for guiding the movable pressure plate 120 is laid on the mold clamping device frame 910. A moving mold 820 is mounted on the surface of the movable pressure plate 120 opposite to the fixed pressure plate 110.

[0030] The moving mechanism 102 performs mold closing, pressurization, mold clamping, demolding, and mold opening of the mold device 800 by moving the movable pressure plate 120 forward and backward relative to the fixed pressure plate 110. The moving mechanism 102 includes an toggle seat 130 spaced apart from the fixed pressure plate 110, a connecting rod 140 connecting the fixed pressure plate 110 and the toggle seat 130, an toggle mechanism 150 that moves the movable pressure plate 120 relative to the toggle seat 130 in the mold opening and closing direction, 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 pressure plate 110 and the toggle seat 130.

[0031] The toggle seat 130 is spaced apart from the fixed pressure plate 110 and is mounted on the mold clamping device frame 910 so as to move freely in the mold opening and closing direction. Furthermore, the toggle seat 130 can be configured to move freely along a guide laid on the mold clamping device frame 910. The guide of the toggle seat 130 can be interchangeable with the guide 101 of the movable pressure plate 120.

[0032] In addition, in this embodiment, the fixed pressure plate 110 is fixed relative to the mold clamping device frame 910, and the toggle seat 130 is configured to move freely relative to the mold clamping device frame 910 in the mold opening and closing direction. However, it is also possible that the toggle seat 130 is fixed relative to the mold clamping device frame 910, and the fixed pressure plate 110 is configured to move freely relative to the mold clamping device frame 910 in the mold opening and closing direction.

[0033] Connecting rods 140 connect the fixed pressure plate 110 and the toggle seat 130 at a distance L in the mold opening and closing direction. Multiple connecting rods 140 can be used (e.g., four). The multiple connecting rods 140 are configured parallel to the mold opening and closing direction and extend according to the clamping force. A connecting rod strain detector 141 for detecting the strain of the connecting rod 140 can be installed on at least one connecting rod 140. The connecting rod strain detector 141 sends a signal indicating its detection result to the control device 700. The detection result of the connecting rod strain detector 141 is used for detecting the clamping force, etc.

[0034] In this embodiment, a connecting rod strain gauge 141 is used as the clamping force detector for detecting the clamping force, but the present invention is not limited to this. The clamping force detector is not limited to a strain gauge and may also be piezoelectric, capacitive, hydraulic, or electromagnetic, etc., and its installation position is not limited to the connecting rod 140.

[0035] A toggle mechanism 150 is positioned between a movable pressure plate 120 and a toggle seat 130, allowing the movable pressure plate 120 to move relative to the toggle seat 130 in the mold opening and closing direction. The toggle mechanism 150 has a crosshead 151 that moves in the mold opening and closing direction and a pair of linkages that extend and retract with the movement of the crosshead 151. Each linkage has a first linkage 152 and a second linkage 153 connected by pins or the like, allowing for free extension and retraction. The first linkage 152 is mounted by pins or the like to allow for free oscillation relative to the movable pressure plate 120. The second linkage 153 is mounted by pins or the like to allow for free oscillation relative to the toggle seat 130. The second linkage 153 is mounted to the crosshead 151 via a third linkage 154. When the crosshead 151 moves forward or backward relative to the toggle seat 130, the first linkage 152 and the second linkage 153 extend and retract, causing the movable pressure plate 120 to move forward or backward relative to the toggle seat 130.

[0036] Furthermore, the structure of the toggle mechanism 150 is not limited to... Figure 1 and Figure 2 The structure shown. For example, in Figure 1 and Figure 2 In this configuration, each link group has 5 nodes, but it can be 4, or it can be the node where one end of the third link 154 is connected to the first link 152 and the second link 153.

[0037] The clamping motor 160 is mounted on the toggle seat 130 and operates the toggle mechanism 150. The clamping motor 160 moves the crosshead 151 forward and backward relative to the toggle seat 130, causing the first link 152 and the second link 153 to extend and retract, thereby moving the movable pressure plate 120 forward and backward relative to the toggle seat 130. The clamping motor 160 is directly connected to the motion conversion mechanism 170, but can also be connected to the motion conversion mechanism 170 via a belt and pulleys.

[0038] The motion conversion mechanism 170 converts the rotary motion of the mold clamping motor 160 into the linear motion of the crosshead 151. The motion conversion mechanism 170 includes a lead screw shaft and a lead screw nut screwed to the lead screw shaft. Balls or rollers may be located between the lead screw shaft and the lead screw nut.

[0039] Under the control of the control device 700, the mold closing device 100 performs the mold closing process, the pressure raising process, the mold closing process, the pressure release process, and the mold opening process.

[0040] In the mold closing process, the mold closing motor 160 is driven to advance the crosshead 151 to the mold closing end position at a set speed, causing the movable pressure plate 120 to advance so that the moving mold 820 contacts the fixed mold 810. For example, a mold closing motor encoder 161 is used to detect the position and speed of the crosshead 151. The mold closing motor encoder 161 detects the rotation of the mold closing motor 160 and sends a signal indicating its detection result to the control device 700.

[0041] Furthermore, the crosshead position detector for detecting the position of the crosshead 151 and the crosshead movement speed detector for detecting the movement speed of the crosshead 151 are not limited to the mold clamping motor encoder 161; conventional detectors can be used. Similarly, the movable platen position detector for detecting the position of the movable platen 120 and the movable platen movement speed detector for detecting the movement speed of the movable platen 120 are not limited to the mold clamping motor encoder 161; conventional detectors can be used.

[0042] In the pressurization process, the mold clamping motor 160 is further driven to advance the crosshead 151 from the mold closing end position to the mold closing position, thereby generating a mold clamping force.

[0043] During the mold closing process, the mold closing motor 160 is driven to maintain the position of the crosshead 151 in the mold closing position. During the mold closing process, the mold closing force generated during the pressurization process is maintained. During the mold closing process, a cavity space 801 (see reference) is formed between the moving mold 820 and the fixed mold 810. Figure 2 The injection unit 300 fills the cavity space 801 with liquid molding material. The filled molding material is then cured to obtain a molded product.

[0044] The number of cavity spaces 801 can be one or more. In the latter case, multiple molded articles can be obtained simultaneously. An insert can be configured in a part of the cavity space 801, and the other part of the cavity space 801 can be filled with molding material. A molded article in which the insert and the molding material are integrated can be obtained.

[0045] During the depressurization process, the crosshead 151 is retracted from the mold-closing position to the mold-opening start position by driving the mold-closing motor 160, thereby causing the movable pressure plate 120 to retract and reducing the mold-closing force. The mold-opening start position and the mold-closing end position can be the same position.

[0046] In the mold opening process, the crosshead 151 is retracted from the mold opening start position to the mold opening end position at a set moving speed by driving the mold closing motor 160, causing the movable pressure plate 120 to retract, so that the moving mold 820 separates from the fixed mold 810. Then, the ejector device 200 ejects the molded product from the moving mold 820.

[0047] The setting conditions in the mold closing process, the pressure raising process, and the mold closing process are set uniformly as a series of setting conditions. For example, the moving speed, position (including the mold closing start position, moving speed switching position, mold closing end position, and mold closing position) and mold closing force of the crosshead 151 in the mold closing process and the pressure raising process are set uniformly as a series of setting conditions. The mold closing start position, moving speed switching position, mold closing end position, and mold closing position are arranged sequentially from back to front, and represent the start and end points of the range for setting the moving speed. The moving speed is set for each range. There can be one or more moving speed switching positions. The moving speed switching position can be omitted. Only the mold closing position and the mold closing force can be set.

[0048] The settings for the depressurization and mold opening processes are also set in the same way. For example, the moving speed and position (mold opening start position, moving speed switching position, and mold opening end position) of the crosshead 151 in the depressurization and mold opening processes are set uniformly as a series of settings. The mold opening start position, moving speed switching position, and mold opening end position are arranged sequentially from front to back, and represent the start and end points of the range for setting the moving speed. The moving speed is set for each range. There can be one or more moving speed switching positions. A moving speed switching position may not be set. The mold opening start position and the mold closing end position can be the same position. Furthermore, the mold opening end position and the mold closing start position can be the same position.

[0049] In addition, the moving speed and position of the movable pressure plate 120 can be set instead of the moving speed and position of the crosshead 151. Furthermore, the clamping force can be set instead of the position of the crosshead (e.g., the mold closing position) and the position of the movable pressure plate.

[0050] However, the toggle mechanism 150 amplifies the driving force of the clamping motor 160 and transmits it to the movable pressure plate 120. This amplification factor is also known as the toggle ratio. The toggle ratio varies depending on the angle θ (hereinafter also referred to as "link angle θ") formed by the first link 152 and the second link 153. The link angle θ is determined by the position of the crosshead 151. The toggle ratio reaches its maximum when the link angle θ is 180°.

[0051] When the thickness of the mold assembly 800 changes due to replacement of the mold assembly 800, temperature changes of the mold assembly 800, etc., mold thickness adjustment is performed to obtain the specified mold closing force during mold closing. In mold thickness adjustment, for example, the distance L between the fixed pressure plate 110 and the toggle seat 130 is adjusted so that the linkage angle θ of the toggle mechanism 150 becomes the specified angle at the moment when the moving mold 820 contacts the fixed mold 810.

[0052] The mold clamping device 100 includes a mold thickness adjustment mechanism 180. The mold thickness adjustment mechanism 180 adjusts the distance L between the fixed pressure plate 110 and the toggle seat 130, thereby adjusting the mold thickness. Furthermore, the timing of the mold thickness adjustment is performed, for example, during the period from the end of the molding cycle to the start of the next molding cycle. The mold thickness adjustment mechanism 180 includes, for example: a lead screw shaft 181 formed at the rear end of the connecting rod 140; a lead screw nut 182 held in the toggle seat 130 for free rotation and non-retractable movement; and a mold thickness adjustment motor 183 that rotates the lead screw nut 182 screwed to the lead screw shaft 181.

[0053] Each connecting rod 140 is provided with a lead screw shaft 181 and a lead screw nut 182. The rotational driving force of the die thickness adjustment motor 183 can be transmitted to multiple lead screw nuts 182 via the rotational driving force transmission unit 185. Multiple lead screw nuts 182 can be rotated synchronously. In addition, by changing the transmission path of the rotational driving force transmission unit 185, multiple lead screw nuts 182 can also be rotated individually.

[0054] The rotary drive force transmission unit 185 is composed of, for example, gears. In this case, driven gears are formed on the outer periphery of each lead screw nut 182, drive gears are mounted on the output shaft of the die thickness adjustment motor 183, and intermediate gears that mesh with multiple driven gears and drive gears are kept rotatably in the center of the toggle seat 130. Alternatively, instead of gears, the rotary drive force transmission unit 185 may also be composed of belts and pulleys.

[0055] The operation of the die thickness adjustment mechanism 180 is controlled by the control device 700. The control device 700 drives the die thickness adjustment motor 183 to rotate the lead screw nut 182. As a result, the position of the toggle seat 130 relative to the connecting rod 140 is adjusted, and the distance L between the fixed pressure plate 110 and the toggle seat 130 is adjusted. Alternatively, multiple die thickness adjustment mechanisms can be used in combination.

[0056] The die thickness adjustment motor encoder 184 is used to detect the interval L. The die thickness adjustment motor encoder 184 detects the rotation amount and direction of the die thickness adjustment motor 183 and sends a signal indicating the detection result to the control device 700. The detection result of the die thickness adjustment motor encoder 184 is used for monitoring and controlling the position of the toggle seat 130 and the interval L. However, the toggle seat position detector for detecting the position of the toggle seat 130 and the interval detector for detecting the interval L are not limited to the die thickness adjustment motor encoder 184; conventional detectors can be used.

[0057] The mold clamping device 100 may have a mold temperature regulator for adjusting the temperature of the mold assembly 800. The mold assembly 800 has a flow path for a temperature regulating medium inside it. The mold temperature regulator adjusts the temperature of the temperature regulating medium supplied to the flow path of the mold assembly 800, thereby regulating the temperature of the mold assembly 800.

[0058] In addition, the mold closing device 100 in this embodiment is a horizontal type with the mold opening and closing direction in the horizontal direction, but it can also be a vertical type with the mold opening and closing direction in the vertical direction.

[0059] Furthermore, the mold clamping device 100 of this embodiment includes a mold clamping motor 160 as a drive unit, but a hydraulic cylinder may be used instead of the mold clamping motor 160. Also, the mold clamping device 100 may include a linear motor for mold opening and closing, or it may include an electromagnet for mold clamping.

[0060] (Ejection device)

[0061] In the description of the ejector device 200, similar to the description of the mold closing device 100, the moving direction of the movable pressure plate 120 when the mold is closed (e.g., the positive X-axis direction) is set to forward, and the moving direction of the movable pressure plate 120 when the mold is opened (e.g., the negative X-axis direction) is set to rearward.

[0062] Ejection device 200 is mounted on movable pressure plate 120 and moves forward and backward together with movable pressure plate 120. Ejection device 200 includes: ejection rod 210 for ejecting molded article from mold device 800; and drive mechanism 220 for moving ejection rod 210 along the moving direction (X-axis direction) of movable pressure plate 120.

[0063] Ejector rod 210 is configured to move freely in and out of the through hole in movable pressure plate 120. The front end of ejector rod 210 contacts ejector plate 826 of moving mold 820. The front end of ejector rod 210 may or may not be connected to ejector plate 826.

[0064] 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 lead screw and a lead screw nut screwed to the lead screw. Balls or rollers may be located between the lead screw and the lead screw nut.

[0065] The ejection device 200 performs the ejection process under the control of the control device 700. In the ejection process, the ejector rod 210 is moved forward from the standby position to the ejection position at a set speed, causing the ejector plate 826 to move forward and eject the molded product. Then, the ejection motor is driven to move the ejector rod 210 backward at a set speed, causing the ejector plate 826 to return to the original standby position.

[0066] For example, an ejector motor encoder is used to detect the position and speed of the ejector rod 210. The ejector motor encoder detects the rotation of the ejector motor and sends a signal indicating its detection result to the control device 700. In addition, the ejector rod position detector for detecting the position of the ejector rod 210 and the ejector rod speed detector for detecting the speed of the ejector rod 210 are not limited to the ejector motor encoder, and conventional detectors can be used.

[0067] (Injection device)

[0068] In the description of the injection device 300, unlike the description of the mold clamping device 100 and the description of the ejection device 200, the direction of movement of the screw 330 during filling (e.g., the negative X-axis direction) is set to forward, and the direction of movement of the screw 330 during metering (e.g., the positive X-axis direction) is set to rearward.

[0069] An injection unit 300 is mounted on a sliding base 301, which is configured to move freely forward and backward relative to the injection unit frame 920. The injection unit 300 is also configured to move freely forward and backward relative to the mold assembly 800. The injection unit 300 contacts the mold assembly 800 and fills the cavity space 801 within the mold assembly 800 with molding material. The injection unit 300 includes, for example, a cylinder 310 for heating the molding material, a nozzle 320 disposed at the front end of the cylinder 310, a screw 330 configured to move freely forward and backward and rotate freely within the cylinder 310, a metering motor 340 for rotating the screw 330, an injection motor 350 for moving the screw 330 forward and backward, and a load detector 360 for detecting the load transmitted between the injection motor 350 and the screw 330.

[0070] The cylinder body 310 heats the molding material supplied to it from the supply port 311. The molding material includes, for example, resin. The molding material is formed in granular form and supplied to the supply port 311 in a solid state. The supply port 311 is formed at the rear of the cylinder body 310. A cooler 312, such as a water-cooled cylinder, is provided on the outer periphery of the rear of the cylinder body 310. A first heater 313, such as a belt heater, and a first temperature detector 314 are provided on the outer periphery of the cylinder body 310, further forward than the cooler 312.

[0071] The cylinder block 310 is divided into multiple regions along its axial direction (e.g., the X-axis direction). A first heater 313 and a first temperature detector 314 are respectively provided in each of the multiple regions. A set temperature is set for each of the multiple regions, 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.

[0072] The nozzle 320 is located at the front end of the cylinder 310 and presses against the mold assembly 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.

[0073] The screw 330 is configured to rotate freely and move forward and backward within the cylinder 310. When the screw 330 is rotated, molding material is conveyed forward along the spiral grooves of the screw 330. As the molding material is conveyed forward, it is gradually melted by heat from the cylinder 310. As the liquid molding material is conveyed forward and accumulates at the front of the cylinder 310, the screw 330 retracts. Then, when the screw 330 is moved forward, the liquid molding material accumulated at the front of the screw 330 is injected from the nozzle 320 and fills the mold assembly 800.

[0074] The check ring 331 is installed at the front of the screw 330 so that it can move freely forward and backward. The check ring 331 acts as a check valve to prevent the molding material from flowing backward from the front of the screw 330 when the screw 330 is pushed forward.

[0075] When the screw 330 is advanced, the check 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 that blocks the flow path of the molding material (see reference). Figure 2 This prevents the molding material accumulated in front of the screw 330 from flowing backward.

[0076] On the other hand, when the screw 330 is rotated, the check ring 331 is pushed forward by the pressure of the molding material being conveyed forward along the spiral groove of the screw 330, and advances relative to the screw 330 to the open position where the flow path of the molding material is opened (see reference). Figure 1 Thus, the molding material is conveyed to the front of the screw 330.

[0077] The check ring 331 can be either a cotransformer that rotates with the screw 330 or a non-cotransformer that does not rotate with the screw 330.

[0078] Additionally, the injection device 300 may have a drive source that moves the check ring 331 back and forth relative to the screw 330 between an open position and a closed position.

[0079] 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, it could be a hydraulic pump.

[0080] The injection motor 350 moves the screw 330 forward and backward. A motion conversion mechanism is provided between the injection motor 350 and the screw 330 to convert the rotational motion of the injection motor 350 into the linear motion of the screw 330. This motion conversion mechanism may include, for example, a lead screw shaft and a lead screw nut screwed to the lead screw shaft. Ball bearings, rollers, etc., may be provided between the lead screw shaft and the lead screw nut. The drive source for moving the screw 330 forward and backward is not limited to the injection motor 350; for example, it may be a hydraulic cylinder.

[0081] Load detector 360 detects the load transmitted between injection motor 350 and screw 330. The detected load is converted into pressure by control device 700. Load detector 360 is positioned along the load transmission path between injection motor 350 and screw 330, and detects the load acting on load detector 360.

[0082] The load detector 360 sends the detected load signal to the control device 700. The load detected by the load detector 360 is converted into the pressure acting between the screw 330 and the molding material, and is used for the control and monitoring of the back pressure of the screw 330 and the pressure acting from the screw 330 on the molding material.

[0083] Furthermore, the pressure detector for detecting the pressure of the molding material is not limited to the load detector 360; conventional detectors can be used. For example, a nozzle pressure sensor or a mold pressure sensor can be used. The nozzle pressure sensor is located at the nozzle 320. The mold pressure sensor is located inside the mold assembly 800.

[0084] The injection unit 300 performs metering, filling, and pressure holding processes under the control of the control unit 700. The filling and pressure holding processes can be collectively referred to as the injection process.

[0085] In the metering process, the metering motor 340 drives the screw 330 to rotate at a set speed, conveying the molding material forward along the spiral grooves of the screw 330. As a result, the molding material is gradually melted. As the molten molding material is conveyed forward of the screw 330 and accumulates at the front of the cylinder 310, the screw 330 retracts. For example, a metering motor encoder 341 is used to detect the rotational speed of the screw 330. The metering motor encoder 341 detects the rotation of the metering motor 340 and sends a signal indicating its detection result to the control device 700. However, the screw speed detector for detecting the rotational speed of the screw 330 is not limited to the metering motor encoder 341; conventional detectors can be used.

[0086] In the metering process, to limit the screw 330 from retracting too rapidly, the injection motor 350 can be driven to apply a set back pressure to the screw 330. For example, a load detector 360 can be used to detect the back pressure on the screw 330. If the screw 330 retracts to the metering end position and a predetermined amount of molding material accumulates in front of the screw 330, the metering process ends.

[0087] The position and speed of the screw 330 in the metering process are uniformly set as a series of preset conditions. For example, the metering start position, speed switching position, and metering end position are set. These positions are arranged sequentially from front to back and represent the start and end points of the set speed interval. The speed is set for each interval. There can be one or more speed switching positions. Alternatively, no speed switching position can be set. Furthermore, the back pressure is set for each interval.

[0088] In the filling process, the injection motor 350 is driven to advance the screw 330 at a set speed, filling the cavity space 801 within the mold assembly 800 with the liquid molding material accumulated in front of the screw 330. For example, an injection motor encoder 351 is used to detect the position and speed of the screw 330. The injection motor encoder 351 detects the rotation of the injection motor 350 and sends a signal indicating its detection result to the control device 700. If the screw 330 reaches the set position, a switch is made from the filling process to the holding pressure process (so-called V / P switching). The position where the V / P switching occurs is also called the V / P switching position. The set speed of the screw 330 can be changed according to the position of the screw 330, time, etc.

[0089] The position and moving speed of the screw 330 in the filling process are uniformly set as a series of preset conditions. For example, the filling start position (also called the "injection start position"), the moving speed switching position, and the V / P switching position are set. These positions are arranged sequentially from back to front and represent the start and end points of the set moving speed interval. The moving speed is set for each interval. There can be one or more moving speed switching positions. It is also possible not to set any moving speed switching positions.

[0090] The upper limit of the pressure of the screw 330 is set for each range of the screw 330's moving speed. The pressure of the screw 330 is detected by the load detector 360. When the pressure of the screw 330 is below the set pressure, the screw 330 moves forward at the set moving speed. On the other hand, when the pressure of the screw 330 exceeds the set pressure, in order to protect the mold, the screw 330 moves forward at a slower moving speed than the set moving speed, so that the pressure of the screw 330 falls below the set pressure.

[0091] Furthermore, during the filling process, after the screw 330 reaches the V / P switching position, it can be paused at the V / P switching position before the V / P switch is performed. Instead of stopping the screw 330 immediately before the V / P switch, the screw 330 can be moved forward or backward at a slight speed. Moreover, the screw position detector for detecting the position of the screw 330 and the screw speed detector for detecting the movement speed of the screw 330 are not limited to the injection motor encoder 351; conventional detectors can be used.

[0092] During the holding pressure process, the injection motor 350 pushes 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 remaining molding material in the cylinder 310 towards the mold assembly 800. This replenishes any insufficient molding material in the mold assembly 800 due to cooling shrinkage. For example, a load detector 360 is used to detect the holding pressure. The set value of the holding pressure can be changed according to the elapsed time since the start of the holding pressure process. The holding pressure and the holding time for each of the multiple holding pressure processes can be set separately, or they can be set uniformly as a series of setting conditions.

[0093] During the holding pressure process, the molding material in the cavity space 801 within the mold assembly 800 is gradually cooled. At the end of the holding pressure process, the inlet of the cavity space 801 is blocked by the solidified molding material. This state is called gate sealing, which prevents the 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 within the cavity space 801 solidifies. To shorten the molding cycle time, a metering process can be performed during the cooling process.

[0094] Furthermore, the injection device 300 in this embodiment is a coaxial screw type, but it can also be a pre-plasticizing type, etc. In a pre-plasticizing type injection device, molten molding material 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, the screw is configured to rotate freely but not retract, or the screw is configured to rotate freely and retract freely. On the other hand, in the injection cylinder, the plunger is configured to retract freely.

[0095] Furthermore, the injection device 300 in this embodiment is horizontal with the cylinder 310's axis in the horizontal direction, but it can also be vertical with the cylinder 310's axis in the vertical direction. The mold clamping device combined with the vertical injection device 300 can be either vertical or horizontal. Similarly, the mold clamping device combined with the horizontal injection device 300 can be either horizontal or vertical.

[0096] (Mobile device)

[0097] In the description of the moving device 400, similarly to the description of the injection device 300, the direction of movement of the screw 330 during filling (e.g., the negative X-axis direction) is set to forward, and the direction of movement of the screw 330 during metering (e.g., the positive X-axis direction) is set to rearward.

[0098] The moving device 400 causes the injection device 300 to move forward and backward relative to the mold device 800. Furthermore, the moving device 400 presses the nozzle 320 relative to the mold device 800 to generate nozzle contact pressure. The moving device 400 includes a hydraulic pump 410, a motor 420 as a drive source, and a hydraulic cylinder 430 as a hydraulic actuator.

[0099] The hydraulic pump 410 has a first port 411 and a second port 412. The hydraulic pump 410 is a bidirectional rotating pump, generating hydraulic pressure by switching the rotation direction of the motor 420, drawing in working fluid (e.g., oil) from either the first port 411 or the second port 412 and discharging it from the other port. Alternatively, the hydraulic pump 410 can also draw working fluid from a tank and discharge working fluid from either the first port 411 or the second port 412.

[0100] Motor 420 operates hydraulic pump 410. Motor 420 drives hydraulic pump 410 by means of rotational direction and rotational torque corresponding to control signals from control device 700. Motor 420 can be an electric motor or an electric servo motor.

[0101] The hydraulic cylinder 430 has a cylinder body 431, a piston 432, and a piston rod 433. The cylinder body 431 is fixed relative to the injection device 300. The piston 432 divides the interior of the cylinder body 431 into a front chamber 435, which serves as a first chamber, and a rear chamber 436, which serves as a second chamber. The piston rod 433 is fixed relative to the fixed pressure plate 110.

[0102] The front chamber 435 of the hydraulic cylinder 430 is connected to the first port 411 of the hydraulic pump 410 via a first flow path 401. Working fluid ejected from the first port 411 is supplied to the front chamber 435 via the first flow path 401, thereby propelling the injection device 300 forward. As the injection device 300 advances, the nozzle 320 is pressed against the fixed mold 810. The front chamber 435 functions as a pressure chamber, generating the nozzle contact pressure of the nozzle 320 through the pressure of the working fluid supplied from the hydraulic pump 410.

[0103] On the other hand, 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 working fluid ejected 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 device 300 backward. The injection device 300 retracts and the nozzle 320 separates from the fixed mold 810.

[0104] In addition, 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 also be used.

[0105] (Control device)

[0106] The control device 700 is, for example, composed of a computer, such as Figures 1-2 As shown, the device includes 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 programs stored in the storage medium 702. Furthermore, the control device 700 receives signals from external sources through the input interface 703 and sends signals to external sources through the output interface 704.

[0107] The control device 700 repeatedly manufactures molded products by performing metering, mold closing, pressurization, mold closing, filling, pressure holding, cooling, depressurization, mold opening, and ejection processes. The series of actions used to obtain the molded product, such as the actions from the start of the metering process to the start of the next metering process, is also called "material injection" or "molding cycle." Furthermore, the time required for one material injection is also called "molding cycle time" or "cycle time."

[0108] A typical molding cycle may include, for example, the following steps in sequence: metering, mold closing, pressure increase, mold closing, filling, pressure holding, cooling, pressure release, mold opening, and ejection. This sequence refers to the order in which each step begins. The filling, pressure holding, and cooling steps occur during the mold closing step. Alternatively, the start of the mold closing step can coincide with the start of the filling step. The end of the pressure release step can coincide with the start of the mold opening step.

[0109] Furthermore, to shorten the molding cycle time, multiple processes can be performed simultaneously. For example, the metering process can be performed during the cooling process of the previous molding cycle or during the mold closing process. In this case, the mold closing process can be set to be performed at the very beginning of the molding cycle. The filling process can also begin during the mold closing process. The ejection process can begin during the mold opening process. When an on / off valve is provided for the flow path of the nozzle 320, the mold opening process can begin during the metering process. This is because even if the mold opening process begins during the metering process, as long as the on / off valve closes the flow path of the nozzle 320, the molding material will not leak from the nozzle 320.

[0110] In addition, a single molding cycle can include processes other than metering, mold closing, pressurization, mold closing, filling, pressure holding, cooling, depressurization, mold opening, and ejection.

[0111] For example, a pre-metering backfeeding process can be performed after the pressure holding process ends and before the metering process begins, to retract the screw 330 to a pre-set metering start position. This reduces the pressure of the molding material accumulated in front of the screw 330 before the metering process begins, preventing the screw 330 from retracting abruptly when the metering process begins.

[0112] Furthermore, a post-metering back suction process can be performed after the metering process is completed and before the filling process begins, retracting the screw 330 to a pre-set filling start position (also known as the "injection start position"). This reduces the pressure of the molding material accumulated in front of the screw 330 before the filling process begins, preventing leakage of the molding material from the nozzle 320 before the filling process begins.

[0113] The control device 700 is connected to the operation device 750, which receives user input, and the display device 760, which displays a screen. The operation device 750 and the display device 760 are, for example, composed of a touch panel 770, and can be integrated. The touch panel 770, as the display device 760, displays a screen under the control of the control device 700. Information such as the settings of the injection molding machine 10 and the current status of the injection molding machine 10 can be displayed on the screen of the touch panel 770. Furthermore, operation sections such as buttons and input fields for receiving user input can be displayed on the screen of the touch panel 770. The touch panel 770, as the operation device 750, detects user input on the screen and outputs a signal corresponding to the input operation to the control device 700. Thus, for example, the user can simultaneously check the information displayed on the screen and operate the operation sections provided on the screen to set the injection molding machine 10 (including inputting setting values). Furthermore, by operating the operation sections provided on the screen, the user can cause the injection molding machine 10 corresponding to the operation sections to operate. Furthermore, the operation of the injection molding machine 10 can include, for example, the operation (including stopping) of the mold clamping device 100, the ejection device 200, the injection device 300, the moving device 400, etc. Also, the operation of the injection molding machine 10 can include switching the screen displayed on the touch panel 770, which is a display device 760.

[0114] Furthermore, while the operation device 750 and display device 760 of this embodiment are integrated into a touch panel 770, they can also be provided independently. Additionally, multiple operation devices 750 can be provided. The operation device 750 and display device 760 are disposed on the operation side (negative Y-axis direction) of the mold clamping device 100 (more specifically, the fixed pressure plate 110).

[0115] (Detailed description of the control device)

[0116] Next, refer to Figure 3An example of the constituent elements of the control device 700 will be described. Furthermore, Figure 3 The functional blocks illustrated are conceptual and do not necessarily need to be physically configured as shown. All or part of each functional block can be distributed or integrated in any unit according to functionality or physical arrangement. All or any part of the processing functions performed by each functional block can be implemented by a program executed by the CPU or by hardware based on wiring logic.

[0117] like Figure 3 As shown, the control device 700 includes, for example, a mold closing control unit 711, an ejection control unit 712, an injection control unit 713, and a metering control unit 714. The mold closing control unit 711 controls the mold closing device 100 and performs... Figure 4 The diagram illustrates the mold closing process, pressure boosting process, mold closing process, pressure release process, and mold opening process. The ejection control unit 712 controls the ejection device 200 and performs the ejection process. The injection control unit 713 controls the injection drive source of the injection device 300 and performs the injection process. The injection drive source is, for example, an injection motor 350, but could also be a hydraulic cylinder, etc. The injection process includes a filling process and a pressure holding process. The injection process is performed during the mold closing process. The metering control unit 714 controls the metering drive source of the injection device 300 and performs the metering process. The metering drive source is, for example, a metering motor 340, but could also be a hydraulic pump, etc. The metering process is performed during the cooling process.

[0118] The filling process is a process of controlling the injection drive source so that the actual value of the moving speed of the injection component located inside the cylinder 310 is equal to a set value. The filling process is a process of filling the mold assembly 800 with liquid molding material accumulated in front of the injection component by moving the injection component forward. The injection component is, for example, a screw 330 (see reference). Figure 1 and Figure 2 (It can also be a plunger.)

[0119] The movement speed of the injection unit is detected using a speed detector. The speed detector is, for example, an injection motor encoder 351. During the filling process, as the injection unit advances, the pressure (hereinafter also referred to as "fill pressure") acting on the molding material from the injection unit increases. The filling process, preceding the holding pressure process, may include a process that temporarily stops the injection unit or a process that retracts the injection unit.

[0120] The holding pressure process is a process of controlling the injection drive source to ensure that the actual filling pressure value is the set value. The holding pressure process replenishes the amount of molding material in the mold assembly 800 that is insufficient due to cooling shrinkage by pressing the injection component forward. The filling pressure is detected using a pressure detector such as a load detector 360. A nozzle pressure sensor or a mold pressure sensor can be used as the pressure detector.

[0121] like Figure 3 As shown, the control device 700 includes a first temperature control unit 715 and a second temperature control unit 716. The first temperature control unit 715 controls the first heater 313 and the cylinder 310 (see reference). Figure 1 and Figure 2 The cylinder 310 heats the molding material. The first temperature control unit 715 controls the first heater 313 so that the temperature detected by the first temperature detector 314 becomes the set temperature.

[0122] The second temperature control unit 716 controls the second heater 323 and the nozzle 320 (see reference). Figure 1 and Figure 2 The nozzle 320 is located at the front end of the cylinder 310 and injects the molding material heated by the cylinder 310 into the interior of the mold assembly 800. The second temperature control unit 716 controls the second heater 323 so that the temperature detected by the second temperature detector 324 becomes the set temperature.

[0123] Next, refer to Figure 5 An example of molding material M flowing into the mold assembly 800 will be described. Molding material M is, for example, resin. Molding material M flows into the cavity space 801 inside the mold assembly 800. Cavity space 801 is formed at the dividing surface 830 between the fixed mold 810 and the moving mold 820. Dividing surface 830 is commonly referred to as the parting line.

[0124] During the switch from the filling process to the holding process (the so-called V / P switch), if the flow front position MP of the molding material M (reference) Figure 5 Within the desired range, gas burning is unlikely to occur. Gas burning occurs when the molding material M flows into the cavity space 801, and the gas in the cavity space 801 is compressed and heated, causing the molding material M to carbonize. When gas burning occurs, the gas in the cavity space 801 has difficulty escaping to the outside of the mold device 800, and the gas tends to remain in the cavity space 801, which may also lead to a defect called incomplete filling. Incomplete filling occurs when the molding material M cools and solidifies before being filled into the cavity space 801.

[0125] The flow front position MP of the molding material M during V / P switching is mainly determined by the V / P switching position of the injection unit, but may also vary due to other factors. One such factor is the temperature of the molding material M injected from the nozzle 320. This temperature is primarily determined by the temperature of the nozzle 320. Furthermore, when the cycle time is short, not only the temperature of the nozzle 320 but also the temperature of the cylinder 310 becomes more important. In particular, the temperature of the region of the cylinder 310 closest to the nozzle 320 among the various regions becomes more important. Hereinafter, the temperature of at least one of the nozzle 320 and the cylinder 310 will be referred to as the target temperature.

[0126] When the object temperature is too low, so-called nozzle blockage occurs. Nozzle blockage is a phenomenon where molding material M is not injected from nozzle 320 even after the filling process begins and the injection unit is advanced. When the injection unit is advanced further and the filling pressure increases sharply, the molding material M is suddenly expelled from nozzle 320 like a dam breaking. As a result, the flow leading edge position MP of the molding material M is prone to change during V / P switching.

[0127] When the molding material M is extruded from nozzle 320 all at once, like a dam bursting, the filling pressure drops sharply. Therefore, when the temperature of nozzle 320 or similar components becomes too low and nozzle blockage occurs, a peak in filling pressure will occur midway through the filling process, especially at the beginning of the filling process (see reference). Figure 6 (Solid line). After the dam breaches, the dam will not be rebuilt, at least during the period of injection component advancement. Therefore, only one peak of filling pressure is generated. Additionally, in Figure 6 In the diagram, the solid line represents the waveform of the filling pressure when the object temperature is too low, and the dashed line represents the waveform of the filling pressure when the object temperature is appropriate.

[0128] On the other hand, when the object temperature is too high, so-called drooling occurs. Drooling is the phenomenon where the nozzle 320 causes the molding material to flow vertically into the mold assembly 800 before the filling process begins. The flowing molding material cools and solidifies inside the mold assembly 800 before the filling process begins. As a result, obstacles that hinder the flow of molding material are created inside the mold assembly 800.

[0129] When drooling occurs, an obstruction is created inside the mold assembly 800 that hinders the flow of molding material, thus causing pulsations in the filling pressure (see reference). Figure 7 (Solid lines and dashed lines). The pulsations of filling pressure repeat with small peaks and small troughs. The reason why pulsations of filling pressure occur instead of peaks is that, unlike dams, obstacles persist throughout the advance of the injection component. Additionally, in Figure 7 In the diagram, the solid line and the single-dotted line represent the waveform of the filling pressure when the object temperature is too high, while the dashed line represents the waveform of the filling pressure when the object temperature is appropriate.

[0130] When drooling occurs, an obstruction is created inside the mold assembly 800, hindering the flow of molding material, and thus also causing deviations in the injection pressure (see reference). Figure 7 (Solid lines and dashed lines). The deviation between the filling pressure caused by drooling is due to the fact that the amount of molding material flowing from nozzle 320 is not controlled, and the position where the flowing molding material cools and solidifies is also not controlled.

[0131] Whether nozzle blockage or drooling has occurred is difficult to determine during the quality inspection of molded products. In the past, skilled workers set the object temperature based on their own experience, while non-skilled workers found it difficult to set the object temperature.

[0132] like Figure 3 As shown, the control device 700 includes a monitoring unit 717. The monitoring unit 717 monitors changes in filling pressure during the filling process. For example, the monitoring unit 717 monitors changes in filling pressure during the first half of the filling process (half the filling time). The monitoring unit 717 uses a pressure detector such as a load detector 360 to obtain the actual value of the filling pressure. Based on the changes in the actual value of the filling pressure during the filling process, it is possible to determine whether nozzle blockage or drooling has occurred. Therefore, by monitoring the changes in the actual value of the filling pressure during the filling process, the setting of the target temperature can be supported. Furthermore, the generation of burnt gas can be suppressed. Not only burnt gas can be suppressed, but also the generation of underfilling can be suppressed.

[0133] like Figure 3 As shown, the control device 700 may include a determination unit 718. The determination unit 718 determines whether the object temperature is appropriate based on the change in the actual value of the filling pressure monitored by the monitoring unit 717. For example, the determination unit 718 determines whether the object temperature is appropriate based on at least one of the following: whether there is a peak in the filling pressure during the filling process, whether there is a pulsation in the filling pressure, and whether there is a deviation between the filling pressure and the injection.

[0134] When a peak in filling pressure occurs during the filling process, especially at the beginning of the filling process (reference...), Figure 6 When the solid line is visible, nozzle blockage occurs, and the object temperature is too low. Therefore, when a peak in filling pressure occurs midway through the filling process, the determination unit 718 determines that nozzle blockage has occurred and that the object temperature is inappropriate.

[0135] When there is a pulsation in filling pressure or a deviation between the filling pressure and the injection pressure during the filling process (refer to...) Figure 7When solid lines and dashed lines are filled, drooling occurs and the object temperature is too high. Therefore, when there is a pulsation in filling pressure or a deviation between filling pressure and material injection during the filling process, the judgment unit 718 determines that the object temperature is inappropriate.

[0136] Furthermore, in this embodiment, the determination unit 718 determines whether the object temperature is appropriate, but the object temperature can also be determined by a worker. That is, in this embodiment, the object temperature is automatically determined, but it can also be determined manually. When manually determining whether the object temperature is appropriate, for example, the display control unit 720 of the control device 700 (see reference) Figure 3 The monitoring results of the monitoring unit 717 are displayed on the display device 760.

[0137] By observing the monitoring results displayed on the monitoring unit 717 of the display device 760, the operator can determine whether the object temperature is appropriate. The content displayed on the display device 760 includes, for example, the waveform of the actual filling pressure and its ideal waveform (reference). Figure 6 The ideal waveform is, for example, the waveform from which qualified products were obtained in the past. The content displayed on the display device 760 may include waveforms of the actual values ​​of the filling pressure multiple times, so that deviations between injections can be observed.

[0138] like Figure 3 As shown, the control device 700 may include a setting change unit 719. The setting change unit 719 changes the target temperature setting based on changes in the actual value of the filling pressure monitored by the monitoring unit 717. This allows for the automatic setting of target temperatures that were previously only set by skilled operators.

[0139] For example, when a peak in filling pressure occurs midway through the filling process, especially at the beginning of the filling process (see reference). Figure 6 When the solid line (above the target temperature) is reached, nozzle blockage occurs and the target temperature is too low. Therefore, the setting change unit 719 changes the target temperature setting to high. The setting change amount can be a fixed amount or an amount corresponding to the height of the peak value. In the latter case, the higher the peak value, the larger the setting change amount. The setting change unit 719 can repeatedly implement the setting change until the peak value of the initial filling pressure in the filling process disappears.

[0140] When there is a pulsation in filling pressure during the filling process (refer to...) Figure 7When the solid line and dashed line are filled, drooling occurs and the object temperature is too high. Therefore, the setting change unit 719 changes the object temperature setting to low. The setting change amount can be a fixed amount or an amount corresponding to the amplitude of the pulsation. In the latter case, the larger the amplitude of the pulsation, the larger the setting change amount. The amplitude of the pulsation is determined based on the difference between the actual waveform and the ideal waveform. The setting change unit 719 can repeatedly implement the setting change until the pulsation of the filling pressure disappears midway through the filling process.

[0141] When there is a deviation in filling pressure between injections during the filling process (refer to...) Figure 7 When the solid line and dashed line are filled, drooling occurs and the object temperature is too high. Therefore, the setting change unit 719 changes the object temperature setting to low. The setting change amount can be a fixed amount or an amount corresponding to the amplitude of the pulsation. In the latter case, the larger the amplitude of the pulsation, the larger the setting change amount. The setting change unit 719 can repeatedly implement the setting change until the pulsation of the filling pressure disappears midway through the filling process.

[0142] The setting change unit 719 can repeatedly change the target temperature setting until the waveform of the filling pressure during the filling process becomes the desired waveform. When nozzle clogging or drooling occurs, it can eliminate the clogging or drooling. Nozzle clogging or drooling is difficult to detect during the quality inspection of molded products, but if it can be detected based on the waveform of the filling pressure, its elimination becomes easy.

[0143] The setting modification unit 719, for example, changes the object temperature in molding cycles after the (n+1)th cycle based on the change in filling pressure during the nth (n is a natural number greater than or equal to 1) molding cycle. In molding cycles after the (n+1)th cycle, nozzle clogging or drooling can be eliminated.

[0144] Furthermore, in this embodiment, the setting change unit 719 changes the setting of the target temperature, but the setting of the target temperature can also be changed by an operator. That is, in this embodiment, the setting of the target temperature is changed automatically, but the setting of the target temperature can also be changed manually.

[0145] For example, while observing the monitoring results displayed on the monitoring unit 717 of the display device 760, the operator changes the object temperature setting. This setting change is made by the operator entering the object temperature into the input field on the screen. The operator can repeat the setting change until the waveform of the filling pressure during the filling process becomes the desired waveform.

[0146] The above describes the embodiments of the control device and control method for the injection molding machine according to the present invention, but the present invention is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations can be made within the scope described in the technical solution. These, of course, also fall within the technical scope of the present invention.

Claims

1. A control device for an injection molding machine, comprising: The monitoring unit monitors changes in the filling pressure acting on the molding material during the filling process of filling the molding material into the mold assembly. The monitoring unit monitors whether the filling pressure exhibits repeated peaks and troughs as it changes during the filling process. The pulsation is the pulsation that occurs when the flow front of the molding material is extruded from the nozzle of the injection molding machine into the interior of the mold device. The control device also has: The setting and adjustment unit, based on the change in filling pressure monitored by the monitoring unit, changes the temperature setting of at least one of the nozzles that inject the molding material into the mold device and the cylinder with the nozzle at its front end. When the pulsation occurs during the filling process, the setting change unit changes the temperature setting to low.

2. A control device for an injection molding machine, comprising: The monitoring unit monitors changes in the filling pressure acting on the molding material during the filling process of filling the molding material into the mold assembly; and The setting and adjustment unit, based on the change in filling pressure monitored by the monitoring unit, changes the temperature setting of at least one of the nozzles that inject the molding material into the mold device and the cylinder with the nozzle at its front end. The monitoring unit monitors whether the filling pressure has sharp peaks as a change in filling pressure during the filling process, and also monitors whether the filling pressure has pulsations with repeated peaks and troughs as a change in filling pressure during the filling process. The sharp peak is the peak value of the flow front of the molding material as it is extruded from the nozzle of the injection molding machine into the interior of the mold assembly. The pulsation is the pulsation that occurs when the flow front of the molding material is extruded from the nozzle of the injection molding machine into the interior of the mold device. The setting change unit is configured to change the temperature setting to high when the sharp peak exists midway through the filling process, and to change the temperature setting to low when the pulsation exists midway through the filling process.

Images