Control device for injection molding machine, injection molding machine, and control method for injection molding machine

Abstract

The invention provides a control device of an injection molding machine, the injection molding machine and a control method of the injection molding machine, and provides a technology for inhibiting poor demolding by inhibiting condensation on the surface of a cavity of a mold device. A control device for an injection molding machine is a control device for an injection molding machine that fills a molding material into a cavity space inside a mold device, and has a temperature regulator control unit that controls a temperature regulator that regulates the temperature of the mold device. The temperature regulator control unit controls the temperature regulator in accordance with a dew point temperature of a surface of the mold device that forms the cavity space.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2023-217608 filed on December 25, 2023. The entire content of the Japanese application is incorporated herein by reference. Technical Field

[0002] The present invention relates to a control device for an injection molding machine, an injection molding machine, and a control method for an injection molding machine. Background Art

[0003] An injection molding machine fills a preheated molding material into a cavity space inside a mold device. By curing the filled molding material, a molded product can be obtained. The shape and size of the molded product are equal to the shape and size of the cavity space. The temperature of the mold device is adjusted by a temperature regulator (for example, refer to Patent Document 1).

[0004] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2023-151745

[0005] The injection molding machine repeats the step of filling a preheated molding material into the cavity space inside the mold device. In this process, the temperature of the surface of the mold device that forms the cavity space gradually rises. Hereinafter, the surface of the mold device that forms the cavity space may sometimes be simply referred to as the cavity surface of the mold device.

[0006] The temperature regulator adjusts the temperature of the mold device so that the temperature of the cavity surface of the mold device finally stabilizes at a temperature that can cure the molding material. The temperature regulator adjusts the temperature of the cavity surface of the mold device, for example, by adjusting the temperature of a temperature control medium supplied to the inside of the mold device. The temperature control medium is not particularly limited and is, for example, water or the like.

[0007] Conventionally, until the mold device is sufficiently heated by the heat of the molding material, the temperature regulator sometimes supplies a temperature control medium having a temperature lower than room temperature to the mold device, so that the temperature of the cavity surface of the mold device sometimes drops below the dew point temperature. As a result, condensation sometimes occurs on the cavity surface.

[0008] If condensation occurs on the cavity surface of the mold device, poor demolding will occur. If poor demolding occurs, maintenance of the mold device or the like is required. Therefore, time and labor are required until mass production of the molded product starts. And molding materials are wasted. Summary of the Invention

[0009] One embodiment of the present invention provides a technique capable of suppressing poor demolding by suppressing condensation on the cavity surface of a mold device.

[0010] The control device of an injection molding machine according to an embodiment of the present invention is a control device of an injection molding machine that fills a cavity space inside a mold device with a molding material, and has a temperature regulator control unit that controls a temperature regulator for adjusting the temperature of the mold device. The temperature regulator control unit controls the temperature regulator based on the dew point temperature of the surface of the mold device that forms the cavity space.

[0011] Advantages of the Invention

[0012] According to an embodiment of the present invention, it is possible to suppress defective demolding by suppressing dew condensation on the cavity surface of the mold device. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a diagram showing the state at the completion of mold opening of an injection molding machine according to an embodiment.

[0014] Figure 2 It is a diagram showing the state at the time of mold clamping of an injection molding machine according to an embodiment.

[0015] Figure 3 It is a diagram showing an example of the components of the control device in functional blocks.

[0016] Figure 4 It is a diagram showing an example of data for calculating the dew point temperature.

[0017] Figure 5 It is a diagram showing another example of data for calculating the dew point temperature.

[0018] Figure 6 It is a flowchart showing an example of the processing performed by the control device.

[0019] Figure 7 It is a flowchart showing an example of the processing performed in S107.

[0020] Figure 8 It is a flowchart showing an example of the processing performed in S109.

[0021] In the figure: 10 - injection molding machine, 700 - control device, 713 - temperature regulator control unit, 800 - mold device, 801 - cavity space, 830 - temperature regulator. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in each drawing, the same or corresponding structures may sometimes be denoted by the same reference numerals, and the description thereof may be omitted.

[0023] (Injection Molding Machine)

[0024] Figure 1 This is a view showing the state of the injection molding machine according to an embodiment when the mold is fully opened. Figure 2 This is a view showing the state of the injection molding machine according to an embodiment when the mold is closed. In this specification, the X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other. The X-axis direction and the Y-axis direction represent the horizontal direction, and the Z-axis direction represents the vertical direction. When the clamping device 100 is horizontal, 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 referred to as the operation side, and the positive side of the Y-axis direction is referred to as the opposite side of the operation side.

[0025] As Figures 1 - 2 shown, the injection molding machine 10 includes: a clamping device 100, a mold opening / closing device 800; an ejector device 200 for ejecting the molded product formed by the mold device 800; an injection device 300 for injecting a molding material into the mold device 800; a moving device 400 for moving the injection device 300 forward and backward relative to the mold device 800; a control device 700 for controlling each component of the injection molding machine 10; and a frame 900 for supporting each component of the injection molding machine 10. The frame 900 includes a clamping device frame 910 for supporting the clamping device 100 and an injection device frame 920 for supporting the injection device 300. The clamping device frame 910 and the injection device frame 920 are respectively provided on the floor 2 via horizontal adjusting casters 930. The control device 700 is arranged in the internal space of the injection device frame 920. Hereinafter, each component of the injection molding machine 10 will be described.

[0026] (Clamping device)

[0027] In the description of the clamping device 100, the moving direction of the movable platen 120 when the mold is closed (for example, the positive X-axis direction) is set as the front, and the moving direction of the movable platen 120 when the mold is opened (for example, the negative X-axis direction) is set as the rear for description.

[0028] The clamping device 100 performs mold closing, pressure boosting, mold clamping, pressure release, and mold opening of the mold device 800. The mold device 800 includes a fixed mold 810 and a movable mold 820.

[0029] The clamping device 100 is, for example, horizontal, and the mold opening / closing direction is the horizontal direction. The clamping device 100 has a fixed platen 110 for mounting the fixed mold 810, a movable platen 120 for mounting the movable mold 820, and a moving mechanism 102 for moving the movable platen 120 relative to the fixed platen 110 in the mold opening / closing direction.

[0030] The fixed platen 110 is fixed to the clamping device frame 910. The fixed mold 810 is mounted on the surface of the fixed platen 110 facing the movable platen 120.

[0031] The movable platen 120 is configured to be movable relative to the mold clamping device frame 910 in the mold opening and closing direction. A guide member 101 for guiding the movable platen 120 is laid on the mold clamping device frame 910. A movable mold 820 is mounted on the surface of the movable platen 120 facing the fixed platen 110.

[0032] The moving mechanism 102 performs mold closing, pressure boosting, mold clamping, pressure release, and mold opening of the mold device 800 by moving the movable platen 120 forward and backward relative to the fixed platen 110. The moving mechanism 102 includes: a toggle seat 130 disposed at an interval from the fixed platen 110; a connecting rod 140 connecting the fixed platen 110 and the toggle seat 130; a toggle mechanism 150 moving the movable platen 120 relative to the toggle seat 130 in the mold opening and closing direction; a mold clamping motor 160 operating the toggle mechanism 150; a motion conversion mechanism 170 converting the rotational motion of the mold clamping motor 160 into a linear motion; and a mold thickness adjustment mechanism 180 adjusting the interval between the fixed platen 110 and the toggle seat 130.

[0033] The toggle seat 130 is disposed at an interval from the fixed platen 110 and is placed on the mold clamping device frame 910 to be movable in the mold opening and closing direction. Additionally, the toggle seat 130 can be configured to be movable along the guide member laid on the mold clamping device frame 910. The guide member of the toggle seat 130 can be common with the guide member 101 of the movable platen 120.

[0034] In addition, in the present embodiment, the fixed platen 110 is fixed to the mold clamping device frame 910 and the toggle seat 130 is configured to be movable relative to the mold clamping device frame 910 in the mold opening and closing direction, but it can also be that the toggle seat 130 is fixed to the mold clamping device frame 910 and the fixed platen 110 is configured to be movable relative to the mold clamping device frame 910 in the mold opening and closing direction.

[0035] The connecting rod 140 connects the fixed platen 110 and the toggle seat 130 with an interval L in the mold opening and closing direction. Multiple (for example, 4) connecting rods 140 can be used. The multiple connecting rods 140 are configured to be parallel to the mold opening and closing direction and extend according to the mold clamping force. A connecting rod strain detector 141 for detecting the strain of the connecting rod 140 can be provided on at least one connecting rod 140. The connecting rod strain detector 141 sends a signal representing its detection result to the control device 700. The detection result of the connecting rod strain detector 141 is used for detection of the mold clamping force, etc.

[0036] In addition, in the present embodiment, the connecting rod strain detector 141 is used as the mold clamping force detector for detecting the mold clamping force, but the present invention is not limited thereto. The mold clamping force detector is not limited to the strain type, and can also be piezoelectric, capacitive, hydraulic, electromagnetic, etc., and its installation position is not limited to the connecting rod 140.

[0037] The toggle mechanism 150 is disposed between the movable platen 120 and the toggle base 130, and moves the movable platen 120 relative to the toggle base 130 in the die opening and closing direction. The toggle mechanism 150 has a crosshead 151 that moves in the die opening and closing direction and a pair of link groups that flex and extend by the movement of the crosshead 151. The pair of link groups each have a first link 152 and a second link 153 that are flexibly connected by a pin or the like. The first link 152 is mounted via a pin or the like so as to be swingable relative to the movable platen 120. The second link 153 is mounted via a pin or the like so as to be swingable relative to the toggle base 130. The second link 153 is mounted to the crosshead 151 via a third link 154. When the crosshead 151 moves forward and backward relative to the toggle base 130, the first link 152 and the second link 153 flex and extend, and the movable platen 120 moves forward and backward relative to the toggle base 130.

[0038] In addition, 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 the number of nodes of each link group is 5, but it can also be 4, and one end of the third link 154 can be joined to the node of the first link 152 and the second link 153.

[0039] The clamping motor 160 is mounted on the toggle base 130 to operate the toggle mechanism 150. The clamping motor 160 flexes and extends the first link 152 and the second link 153 by moving the crosshead 151 forward and backward relative to the toggle base 130, thereby moving the movable platen 120 forward and backward relative to the toggle base 130. The clamping motor 160 is directly connected to the motion conversion mechanism 170, but it can also be connected to the motion conversion mechanism 170 via a belt and a pulley or the like.

[0040] The motion conversion mechanism 170 converts the rotational motion of the clamping motor 160 into the linear motion of the crosshead 151. The motion conversion mechanism 170 includes a lead screw shaft and a lead screw nut that engages with the lead screw shaft. A ball or a roller can be present between the lead screw shaft and the lead screw nut.

[0041] The clamping device 100 performs a mold closing process, a pressure boosting process, a clamping process, a pressure releasing process, a mold opening process, etc. under the control of the control device 700.

[0042] In the mold closing process, the clamping motor 160 is driven to move the crosshead 151 forward to the mold closing completion position at a set moving speed to move the movable platen 120 forward, thereby bringing the movable mold 820 into contact with the fixed mold 810. For example, a clamping motor encoder 161 or the like is used to detect the position and moving speed of the crosshead 151. The clamping motor encoder 161 detects the rotation of the clamping motor 160 and sends a signal representing the detection result to the control device 700.

[0043] In addition, the crosshead position detector for detecting the position of the crosshead 151 and the crosshead moving speed detector for detecting the moving speed of the crosshead 151 are not limited to the clamping motor encoder 161, and ordinary detectors can be used. Also, the movable platen position detector for detecting the position of the movable platen 120 and the movable platen moving speed detector for detecting the moving speed of the movable platen 120 are not limited to the clamping motor encoder 161, and ordinary detectors can be used.

[0044] In the boosting process, the clamping motor 160 is further driven to move the crosshead 151 from the mold closing completed position to the mold clamping position, thereby generating a mold clamping force.

[0045] In the mold clamping process, the 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 boosting process is maintained. In the mold clamping process, a cavity space 801 is formed between the movable mold 820 and the fixed mold 810 (refer to Figure 2 ), and the injection device 300 fills the cavity space 801 with a liquid molding material. The filled molding material is cured to obtain a molded product.

[0046] The number of cavity spaces 801 can be one or multiple. In the latter case, multiple molded products can be obtained simultaneously. Inserts can be arranged in a part of the cavity space 801, and the molding material can be filled in another part of the cavity space 801. A molded product in which the insert and the molding material are integrated can be obtained.

[0047] In the pressure release process, the crosshead 151 is retracted from the mold clamping position to the mold opening start position by driving the clamping motor 160 to retract the movable platen 120, thereby reducing the mold clamping force. The mold opening start position and the mold closing completed position can be the same position.

[0048] In the mold opening process, the crosshead 151 is retracted from the mold opening start position to the mold opening completed position at a set moving speed by driving the clamping motor 160 to retract the movable platen 120, thereby separating the movable mold 820 from the fixed mold 810. Then, the ejecting device 200 ejects the molded product from the movable mold 820.

[0049] The setting conditions in the mold closing process, pressure boosting process, and mold clamping process are set together as a series of setting conditions. For example, the moving speed, position (including the mold closing start position, moving speed switching position, mold closing completion position, and mold clamping position) of the crosshead 151 and the mold clamping force in the mold closing process and pressure boosting process are set together as a series of setting conditions. The mold closing start position, moving speed switching position, mold closing completion position, and mold clamping position are arranged in sequence from the rear to the front, and represent the start and end points of the interval where the moving speed is set. The moving speed is set for each interval. The moving speed switching position can be one or more. The moving speed switching position may not be set. Only either the mold clamping position or the mold clamping force may be set.

[0050] The setting conditions in the pressure release process and mold opening process 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 completion position) of the crosshead 151 in the pressure release process and mold opening process are set together as a series of setting conditions. The mold opening start position, moving speed switching position, and mold opening completion position are arranged in sequence from the front to the rear, and represent the start and end points of the interval where the moving speed is set. The moving speed is set for each interval. The moving speed switching position can be one or more. The moving speed switching position may not be set. The mold opening start position and the mold closing completion position can be the same position. Also, the mold opening completion position and the mold closing start position can be the same position.

[0051] In addition, the moving speed, position, etc. of the movable platen 120 can be set instead of the moving speed, position, etc. of the crosshead 151. Also, the mold clamping force can be set instead of the position of the crosshead (for example, the mold clamping position) and the position of the movable platen.

[0052] However, the toggle mechanism 150 amplifies the driving force of the mold clamping motor 160 and transmits it to the movable platen 120. Its magnification ratio is also called the toggle ratio. The toggle ratio changes according to the angle θ formed by the first link 152 and the second link 153 (hereinafter, also referred to as "link angle θ"). The link angle θ is obtained based on the position of the crosshead 151. When the link angle θ is 180°, the toggle ratio becomes the maximum.

[0053] When the thickness of the mold device 800 changes due to replacement of the mold device 800, temperature change of the mold device 800, etc., mold thickness adjustment is performed to obtain a specified mold clamping force during mold clamping. In the mold thickness adjustment, for example, the interval L between the fixed platen 110 and the toggle seat 130 is adjusted so that the link angle θ of the toggle mechanism 150 becomes a specified angle at the moment when the movable mold 820 contacts the fixed mold 810.

[0054] The mold clamping device 100 has a mold thickness adjusting mechanism 180. The mold thickness adjusting mechanism 180 adjusts the mold thickness by adjusting the interval L between the fixed platen 110 and the toggle seat 130. In addition, the timing of 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 adjusting mechanism 180 has, for example: a lead screw shaft 181 formed at the rear end of the connecting rod 140; a lead screw nut 182 rotatably held on the toggle seat 130 without being able to move forward and backward; and a mold thickness adjustment motor 183 that rotates the lead screw nut 182 screwed with the lead screw shaft 181.

[0055] A lead screw shaft 181 and a lead screw nut 182 are provided for each connecting rod 140. The rotational driving force of the mold thickness adjustment motor 183 can be transmitted to a plurality of lead screw nuts 182 via a rotational driving force transmission portion 185. The plurality of lead screw nuts 182 can be rotated synchronously. In addition, by changing the transmission path of the rotational driving force transmission portion 185, the plurality of lead screw nuts 182 can be rotated individually.

[0056] The rotational driving force transmission portion 185 is formed of, for example, gears. At this time, a driven gear is formed on the outer periphery of each lead screw nut 182, a driving gear is mounted on the output shaft of the mold thickness adjustment motor 183, and an intermediate gear meshing with the plurality of driven gears and the driving gear is rotatably held at the center of the toggle seat 130. In addition, the rotational driving force transmission portion 185 can be formed of a belt, a pulley, etc. instead of gears.

[0057] The operation of the mold thickness adjusting mechanism 180 is controlled by the control device 700. The control device 700 drives the mold 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 interval L between the fixed platen 110 and the toggle seat 130 is adjusted. In addition, a plurality of mold thickness adjusting mechanisms can be used in combination.

[0058] The interval L is detected using a mold thickness adjustment motor encoder 184. The mold thickness adjustment motor encoder 184 detects the rotation amount and rotation direction 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 for monitoring and controlling the position of the toggle seat 130 and the interval L. In addition, 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 mold thickness adjustment motor encoder 184, and ordinary detectors can be used.

[0059] The mold clamping device 100 may have a mold temperature regulator for adjusting the temperature of the mold device 800. The mold device 800 has a flow path for a temperature regulating medium inside it. The mold temperature regulator adjusts the temperature of the mold device 800 by adjusting the temperature of the temperature regulating medium supplied to the flow path of the mold device 800.

[0060] In addition, the mold clamping device 100 of the present embodiment is a horizontal type with the mold opening and closing direction being horizontal, but it can also be a vertical type with the mold opening and closing direction being vertical.

[0061] In addition, the mold clamping device 100 of the present embodiment has a mold clamping motor 160 as a driving unit, but it can also have a hydraulic cylinder instead of the mold clamping motor 160. Moreover, the mold clamping device 100 can have a linear motor for mold opening and closing, and can have an electromagnet for mold clamping.

[0062] (Ejector device)

[0063] In the description of the ejector device 200, similar to the description of the mold clamping device 100, the moving direction of the movable platen 120 at the time of mold closing (for example, the positive X-axis direction) is set as the front, and the moving direction of the movable platen 120 at the time of mold opening (for example, the negative X-axis direction) is set as the rear for the description.

[0064] The ejector device 200 is installed on the movable platen 120 and moves forward and backward together with the movable platen 120. The ejector device 200 has: an ejector rod 210 that ejects the molded product from the mold device 800; and a drive mechanism 220 that moves the ejector rod 210 in the moving direction (X-axis direction) of the movable platen 120.

[0065] The ejector rod 210 is configured to be able to move forward and backward freely in the through hole of the movable platen 120. The front end portion of the ejector rod 210 contacts the ejector plate 826 of the movable mold 820. The front end portion of the ejector rod 210 can be connected to the ejector plate 826 or can be not connected thereto.

[0066] The drive mechanism 220 has, 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 shaft and a lead screw nut that is screwed onto the lead screw shaft. There can be balls or rollers between the lead screw shaft and the lead screw nut.

[0067] The ejector device 200 performs an ejection process under the control of the control device 700. In the ejection process, the ejector plate 826 is advanced by moving the ejector rod 210 from the standby position to the ejection position at a set moving speed, thereby ejecting the molded product. Then, the ejector motor is driven to move the ejector rod 210 backward at a set moving speed, and the ejector plate 826 is retracted to the original standby position.

[0068] For example, an ejection motor encoder is used to detect the position and moving speed of the ejection rod 210. The ejection motor encoder detects the rotation of the ejection motor and sends a signal representing the detection result to the control device 700. In addition, the ejection rod position detector for detecting the position of the ejection rod 210 and the ejection rod moving speed detector for detecting the moving speed of the ejection rod 210 are not limited to the ejection motor encoder, and conventional detectors can be used.

[0069] (Injection device)

[0070] In the description of the injection device 300, different from the description of the clamping device 100 and the ejection device 200, the moving direction of the screw 330 during filling (for example, the negative X-axis direction) is set as the front, and the moving direction of the screw 330 during metering (for example, the positive X-axis direction) is set as the rear for description.

[0071] The injection device 300 is provided on the sliding base 301, and the sliding base 301 is configured to be retractable relative to the injection device frame 920. The injection device 300 is configured to be retractable relative to the mold device 800. The injection device 300 contacts the mold device 800 and fills the cavity space 801 in the mold device 800 with the molding material. The injection device 300 has, for example: a cylinder block 310 for heating the molding material; a nozzle 320 provided at the front end of the cylinder block 310; a screw 330 configured to be retractable and rotatable within the cylinder block 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.

[0072] The cylinder block 310 heats the molding material supplied to the inside from the supply port 311. The molding material includes, for example, resin. The molding material is formed into, for example, granular form and is supplied to the supply port 311 in a solid state. The supply port 311 is formed at the rear of the cylinder block 310. A cooler 312 such as a water-cooled cylinder is provided on the outer periphery of the rear part of the cylinder block 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 block 310 further forward than the cooler 312.

[0073] The cylinder block 310 is divided into a plurality of regions along the axial direction of the cylinder block 310 (for example, the X-axis direction). The first heater 313 and the first temperature detector 314 are provided in the plurality of regions respectively. A set temperature is set for each of the plurality of regions, and the control device 700 controls the first heater 313 so that the detected temperature of the first temperature detector 314 becomes the set temperature.

[0074] The nozzle 320 is provided at the front end of the cylinder block 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.

[0075] The screw 330 is configured to be rotatable and movable forward and backward within the cylinder block 310. When the screw 330 is rotated, the molding material is conveyed forward along the spiral groove of the screw 330. While being conveyed forward, the molding material is gradually melted by the heat from the cylinder block 310. As the liquid molding material is conveyed to the front of the screw 330 and accumulates in the front part of the cylinder block 310, the screw 330 is retracted. Then, when the screw 330 is advanced, the liquid molding material accumulated in front of the screw 330 is injected from the nozzle 320 and filled into the mold device 800.

[0076] A check ring 331 is movably mounted at the front of the screw 330. The check ring 331 serves as a check valve to prevent the molding material from flowing backward from the front of the screw 330 to the rear when the screw 330 is pushed forward.

[0077] 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 thus relatively retracts with respect to the screw 330 to a closed position where the flow path of the molding material is blocked (refer to Figure 2 ). Thereby, the molding material accumulated in front of the screw 330 is prevented from flowing backward.

[0078] On the other hand, when the screw 330 is rotated, the check ring 331 is pushed forward by the pressure of the molding material conveyed forward along the spiral groove of the screw 330, and thus relatively advances with respect to the screw 330 to an open position where the flow path of the molding material is opened (refer to Figure 1 ). Thereby, the molding material is conveyed to the front of the screw 330.

[0079] The check ring 331 can 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.

[0080] In addition, the injection device 300 can have a drive source for moving the check ring 331 forward and backward between the open position and the closed position with respect to the screw 330.

[0081] 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 can also be a hydraulic pump or the like.

[0082] The injection motor 350 moves the screw 330 forward and backward. A motion conversion mechanism, etc., which converts the rotational motion of the injection motor 350 into the linear motion of the screw 330, is provided between the injection motor 350 and the screw 330. The motion conversion mechanism, for example, has a lead screw shaft and a lead screw nut that engages with the lead screw shaft. A ball, a roller, etc. can 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, and for example, a hydraulic cylinder, etc. can also be used.

[0083] 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.

[0084] The load detector 360 sends the signal of the detected load 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 pressure that the screw 330 bears from the molding material, the back pressure on the screw 330, and the pressure acting on the molding material from the screw 330, etc.

[0085] In addition, the pressure detector for detecting 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 an in-mold pressure sensor can be used. The nozzle pressure sensor is provided on the nozzle 320. The in-mold pressure sensor is provided inside the mold device 800.

[0086] The injection device 300 performs a metering process, a filling process, a holding pressure process, etc. under the control of the control device 700. The filling process and the holding pressure process can be collectively referred to as an injection process.

[0087] In the metering process, the metering motor 340 is driven to rotate the screw 330 at a set speed, so that the molding material is conveyed forward along the spiral groove of the screw 330. Thus, the molding material is gradually melted. As the liquid molding material is conveyed to the front of the screw 330 and accumulates in the front part of the cylinder block 310, the screw 330 moves backward. For example, the metering motor encoder 341 is used to detect the rotation speed of the screw 330. The metering motor encoder 341 detects the rotation of the metering motor 340 and sends the signal representing the detection result to the control device 700. In addition, the screw rotation speed detector for detecting the rotation speed of the screw 330 is not limited to the metering motor encoder 341, and a general detector can be used.

[0088] In the metering process, in order to limit the rapid retraction of the screw 330, the injection motor 350 can be driven to apply a set back pressure to the screw 330. For example, the load detector 360 is used to detect the back pressure on the screw 330. When the screw 330 retracts to the metering completion position and a specified amount of molding material accumulates in front of the screw 330, the metering process is completed.

[0089] The position and rotation speed of the screw 330 in the metering process are set together as a series of set conditions. For example, the metering start position, the rotation speed switching position, and the metering completion position are set. These positions are arranged in order from the front side to the rear side, and represent the starting point and the ending point of the interval where the set rotation speed is located. The rotation speed is set for each interval. The rotation speed switching position can be one or multiple. The rotation speed switching position may not be set. Also, the back pressure is set for each interval.

[0090] In the filling process, the injection motor 350 is driven to make the screw 330 advance 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. For example, the injection motor encoder 351 is used to detect the position and moving speed of the screw 330. The injection motor encoder 351 detects the rotation of the injection motor 350 and sends a signal representing the detection result to the control device 700. When the position of the screw 330 reaches the set position, the switch from the filling process to the holding pressure process (so-called V / P switch) is performed. The position where the V / P switch is performed is also called the V / P switching position. The set moving speed of the screw 330 can be changed according to the position and time of the screw 330, etc.

[0091] The position and moving speed of the screw 330 in the filling process are set together as a series of set 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 in order from the rear side to the front side, and represent the starting point and the ending point of the interval where the set moving speed is located. The moving speed is set for each interval. The moving speed switching position can be one or multiple. The moving speed switching position may not be set.

[0092] The upper limit value of the pressure of the screw 330 is set for each interval where the moving speed of the screw 330 is set. 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 advances at the set moving speed. On the other hand, when the pressure of the screw 330 exceeds the set pressure, for the purpose of protecting the mold, the screw 330 advances at a moving speed slower than the set moving speed so that the pressure of the screw 330 becomes below the set pressure.

[0093] In addition, in the filling process, after the position of the screw 330 reaches the V / P switching position, the screw 330 can be temporarily stopped at the V / P switching position, and then the V / P switching is performed. Alternatively, before the V / P switching is about to be performed, the screw 330 can be advanced or retracted at a very low speed instead of stopping the screw 330. Moreover, the screw position detector for detecting the position of the screw 330 and the screw moving speed detector for detecting the moving speed of the screw 330 are not limited to the injection motor encoder 351, and ordinary detectors can be used.

[0094] In the holding pressure process, the injection motor 350 is driven to push the screw 330 forward, and the pressure of the molding material at the front end of the screw 330 (hereinafter, also referred to as "holding pressure") is maintained at a set pressure, and the molding material remaining in the cylinder 310 is pushed toward the mold device 800. It is possible to supplement the insufficient amount of molding material caused by the cooling shrinkage in the mold device 800. For example, the 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 and the like. Multiple holding pressures and holding times for maintaining the holding pressure can be set respectively in the holding pressure process, or they can be set together as a series of set conditions.

[0095] In the holding pressure process, the molding material in the cavity space 801 in the mold device 800 is gradually cooled, and when the holding pressure process is completed, the inlet of the cavity space 801 is blocked by the solidified molding material. This state is called gate sealing, which can prevent the molding material from flowing back from the cavity space 801. After the holding pressure process, the cooling process starts. In the cooling process, the molding material in the cavity space 801 is solidified. For the purpose of shortening the molding cycle time, the metering process can be performed in the cooling process.

[0096] In addition, the injection device 300 of the present embodiment is of a coaxial screw type, but it can also be a pre-plasticizing type or the like. The pre-plasticizing type injection device supplies the molding material melted in the plasticizing cylinder to the injection cylinder and injects the molding material from the injection cylinder into the mold device. In the plasticizing cylinder, the screw is configured to be rotatable and non-retractable, or the screw is configured to be rotatable and retractable. On the other hand, in the injection cylinder, the plunger is configured to be retractable.

[0097] Moreover, the injection device 300 of the present embodiment is a horizontal type with the axial direction of the cylinder 310 being the horizontal direction, but it can also be a vertical type with the axial direction of the cylinder 310 being the up and down direction. The mold clamping device combined with the vertical injection device 300 can be vertical or horizontal. Similarly, the mold clamping device combined with the horizontal injection device 300 can be horizontal or vertical.

[0098] (Moving device)

[0099] In the description of the mobile 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 set as the front, and the moving direction of the screw 330 during metering (e.g., the positive X-axis direction) is set as the rear for the description.

[0100] The mobile device 400 moves the injection device 300 forward and backward relative to the mold device 800. Moreover, the mobile device 400 presses the nozzle 320 against the mold device 800 to generate a nozzle contact pressure. The mobile device 400 includes a hydraulic pump 410, a motor 420 as a drive source, and a hydraulic cylinder 430 as a hydraulic actuator, etc.

[0101] The hydraulic pump 410 has a first port 411 and a second port 412. The hydraulic pump 410 is a bidirectional rotary pump. By switching the rotation direction of the motor 420, it sucks the working fluid (e.g., oil) from either the first port 411 or the second port 412 and discharges it from the other port to generate hydraulic pressure. Additionally, the hydraulic pump 410 can also suck the working fluid from the tank and discharge the working fluid from either the first port 411 or the second port 412.

[0102] The motor 420 operates the hydraulic pump 410. The motor 420 drives the hydraulic pump 410 in a rotation direction and torque corresponding to the control signal from the control device 700. The motor 420 can be an electric motor or an electric servo motor.

[0103] 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 the first chamber and a rear chamber 436 as the second chamber. The piston rod 433 is fixed to the fixed platen 110.

[0104] 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. The working fluid discharged from the first port 411 is supplied to the front chamber 435 via the first flow path 401, thereby pushing 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, and the nozzle contact pressure of the nozzle 320 is generated by the pressure of the working fluid supplied from the hydraulic pump 410.

[0105] 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 a second flow path 402. The working fluid discharged from the second port 412 is supplied to the rear chamber 436 of the hydraulic cylinder 430 via the second flow path 402, thereby pushing the injection device 300 backward. As the injection device 300 retreats, the nozzle 320 moves away from the fixed mold 810.

[0106] In addition, in this embodiment, the mobile device 400 includes a hydraulic cylinder 430, but the present invention is not limited thereto. For example, an electric motor and a motion conversion mechanism that converts the rotational motion of the electric motor into a linear motion of the injection device 300 may be used instead of the hydraulic cylinder 430.

[0107] (Control device)

[0108] The control device 700 is constituted by a computer, for example, as Figures 1 - 2 shown, it has a CPU (Central Processing Unit), 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. Also, the control device 700 receives signals from the outside through the input interface 703 and sends signals to the outside through the output interface 704.

[0109] The control device 700 repeatedly manufactures molded products by repeatedly performing processes such as a metering process, a mold closing process, a pressure boosting process, a mold clamping process, a filling process, a pressure holding process, a cooling process, a pressure release process, a mold opening process, and an ejection process. A series of actions for obtaining a molded product, for example, actions from the metering process to before the start of the next metering process, are also referred to as "injection" or "molding cycle". Also, the time required for one injection is also referred to as "molding cycle time" or "cycle time".

[0110] One molding cycle, for example, sequentially includes a metering process, a mold closing process, a pressure boosting process, a mold clamping process, a filling process, a pressure holding process, a cooling process, a pressure release process, a mold opening process, and an ejection process. The order here is the order in which each process starts. The filling process, the pressure holding process, and the cooling process are performed during the mold clamping process. The start of the mold clamping process may coincide with the start of the filling process. The completion of the pressure release process coincides with the start of the mold opening process.

[0111] In addition, for the purpose of shortening 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. Also, the filling process may start during the mold closing process. And the ejection process may start during the mold opening process. When there is an on-off valve for the flow path of the on-off nozzle 320, the mold opening process may start during the metering process. This is because, even if the mold opening process starts 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.

[0112] In addition, a single molding cycle may include processes other than the metering process, mold closing process, pressure boosting process, mold clamping process, filling process, pressure holding process, cooling process, pressure releasing process, mold opening process, and ejection process.

[0113] For example, before the metering process starts after the pressure holding process is completed, a pre-metering backflow process of retracting the screw 330 to a preset metering start position can be performed. The pressure of the molding material accumulated in front of the screw 330 can be reduced before the metering process starts, thereby preventing the screw 330 from rapidly retracting when the metering process starts.

[0114] Also, before the filling process starts after the metering process is completed, a post-metering backflow process of retracting the screw 330 to a preset filling start position (also referred to as "injection start position") can be performed. The pressure of the molding material accumulated in front of the screw 330 can be reduced before the filling process starts, thereby preventing the molding material from leaking from the nozzle 320 before the filling process starts.

[0115] The control device 700 is connected to the operation device 750 that receives the input operations of the user and the display device 760 of the display screen. The operation device 750 and the display device 760 can be constituted by a touch panel 770 and integrated, for example. The touch panel 770 serving 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 state of the injection molding machine 10 can be displayed on the screen of the touch panel 770, for example. Also, operation parts such as buttons and input fields for receiving the input operations of the user can be displayed on the screen of the touch panel 770, for example. The touch panel 770 serving as the operation device 750 detects the input operations of the user on the screen and outputs a signal corresponding to the input operation to the control device 700. Thus, for example, the user can operate the operation parts provided on the screen while confirming the information displayed on the screen to perform the settings (including input of set values) of the injection molding machine 10, etc. Also, by the user operating the operation parts provided on the screen, the injection molding machine 10 corresponding to the operation parts can be made to operate. In addition, the operation of the injection molding machine 10 can be, 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 be the switching of the screen displayed on the touch panel 770 serving as the display device 760, etc.

[0116] In addition, the operation device 750 and the display device 760 of the present embodiment are integrated into the touch panel 770, but they may also be provided independently. Further, 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 device 100 (more specifically, the fixed platen 110).

[0117] (Detailed description of the control device)

[0118] Next, an example of the components of the control device 700 will be described. In addition, Figure 3 each functional block illustrated in Figure 3 is a conceptual functional block, and physically, it is not necessarily configured as illustrated. All or part of each functional block can be functionally or physically dispersed or integrated in any unit. All or any part of the processing functions performed in each functional block can be implemented by a program executed by a CPU or as hardware based on wiring logic.

[0119] As Figure 3 shown, the control device 700 has, for example, a first acquisition unit 711, an estimation unit 712, a temperature regulator control unit 713, a second acquisition unit 714, and a display control unit 715. The first acquisition unit 711 acquires the temperature T0 and the humidity H0 of the surrounding environment of the injection molding machine 10. The estimation unit 712 estimates the dew point temperature DP of the cavity surface of the mold device 800 based on the temperature T0 and the humidity H0 acquired by the first acquisition unit 711. The cavity surface is the surface that forms the cavity space 801 (refer to Figure 1 and Figure 2 ). The temperature regulator control unit 713 controls the temperature regulator 830 based on the dew point temperature DP of the cavity surface of the mold device 800. The second acquisition unit 714 acquires the temperature T2 of the cavity surface of the mold device 800. The display control unit 715 controls the display device 760. Hereinafter, each structure will be described.

[0120] As described above, the first acquisition unit 711 acquires the temperature T0 and the humidity H0 of the surrounding environment of the injection molding machine 10. The temperature T0 is, for example, the temperature inside the factory where the injection molding machine 10 is installed, and it is acquired by the temperature sensor 721. Further, the humidity H0 is, for example, the humidity inside the factory where the injection molding machine 10 is installed, and it is acquired by the humidity sensor 722. The humidity H0 may be relative humidity or absolute humidity. Relative humidity is the ratio of the partial pressure of water vapor to the saturated vapor pressure (partial pressure of water vapor / saturated vapor pressure). Absolute humidity is the weight of the amount of water vapor contained in 1 kg of dry air.

[0121] The temperature sensor 721 detects the temperature T0 and sends an electrical signal representing the detection result to the first acquisition unit 711. Also, the humidity sensor 722 detects the humidity H0 and sends an electrical signal representing the detection result to the first acquisition unit 711. The temperature sensor 721 and the humidity sensor 722 are installed, for example, on the mold closing cover covering the mold closing device 100. In addition, the installation locations of the temperature sensor 721 and the humidity sensor 722 are not particularly limited. The temperature sensor 721 and the humidity sensor 722 may be provided as part of the injection molding machine 10, or may be provided separately from the injection molding machine 10. A sensor that also serves as the temperature sensor 721 and the humidity sensor 722 can be used.

[0122] As described above, the estimation unit 712 estimates the dew point temperature DP of the cavity surface of the mold device 800 based on the temperature T0 and the humidity H0 acquired by the first acquisition unit 711. The dew point temperature DP is the temperature at which condensation occurs during the cooling of the air, and is the temperature at which the air and water are in equilibrium and saturated. The dew point temperature DP varies according to the weather. Alternatively, the dew point temperature DP varies according to the air conditioning in the factory where the injection molding machine 10 is installed.

[0123] The estimation unit 712 has a database representing the relationship between the temperature T0, the humidity H0, and the dew point temperature DP, and estimates the dew point temperature DP based on this database. For example, the estimation unit 712 has a Figure 4 psychrometric chart as shown. In Figure 4 , point A is the state point when T0 is 25 °C and H0 is 60% RH. Point B is the point obtained by moving point A in the direction of the cooling air temperature T0 ( Figure 4 the left direction in the figure) until it intersects the saturation line. The temperature of point B (for example, 17 °C) is the dew point temperature DP.

[0124] In addition, as Figure 5 shown, the estimation unit 712 may have a tabular database. If the estimation unit 712 has a tabular database, interpolation or extrapolation can be used to estimate the dew point temperature DP. The format of the database is not particularly limited.

[0125] As described above, the temperature regulator control unit 713 controls the temperature regulator 830 based on the dew point temperature DP of the cavity surface of the mold device 800. For example, the temperature regulator control unit 713 controls the set temperature T1ref of the temperature regulator 830. The temperature regulator 830 has a temperature sensor that measures the temperature T1 of the temperature regulator 830, and performs feedback control on the temperature T1 so that the measured temperature T1 coincides with the set temperature T1ref. The temperature regulator 830 adjusts the temperature T2 of the cavity surface of the mold device 800 by adjusting the temperature T1 of the temperature control medium supplied to the inside of the mold device 800, for example. The temperature control medium is not particularly limited, and is, for example, water or the like. The temperature regulator 830 has a temperature sensor that measures the temperature T1 of the temperature control medium, and transmits an electrical signal indicating the measurement result of the temperature sensor to the temperature regulator control unit 713.

[0126] In order to circulate the temperature control medium, the temperature regulator 830 can first adjust the temperature T1 of the temperature control medium discharged from the inside of the mold device 800 to the outside, and then return the temperature control medium to the inside of the mold device 800. The temperature sensor of the temperature regulator 830 can detect the temperature of the temperature control medium after temperature adjustment, or can detect the temperature of the temperature control medium before temperature adjustment.

[0127] However, the injection molding machine 10 repeatedly performs the step of filling the cavity space 801 inside the mold device 800 with the preheated molding material. During this process, the temperature T2 of the cavity surface of the mold device 800 gradually rises. The set temperature T1ref is set in such a way that the temperature T2 of the cavity surface finally stabilizes at a temperature that can cure the molding material. The set temperature T1ref (specifically, the second set temperature T1ref_final described later) uses, for example, the temperature input to the operation device 750.

[0128] The set temperature T1ref (specifically, the second set temperature T1ref_final described later) is sometimes set to a temperature lower than room temperature (specifically, the temperature T0 acquired by the first acquisition unit 711). Assuming that the temperature regulator 830 supplies the temperature control medium having a temperature T1 lower than room temperature to the mold device 800 until the mold device 800 is sufficiently heated by the heat of the molding material, the temperature T2 of the cavity surface of the mold device 800 may become lower than the dew point temperature DP. DP is usually less than T0.

[0129] As described above, the temperature regulator control unit 713 controls the temperature regulator 830 based on the dew point temperature DP of the cavity surface of the mold device 800. Therefore, the temperature T2 of the cavity surface of the mold device 800 can be maintained higher than the dew point temperature DP. As a result, condensation on the cavity surface of the mold device 800 can be suppressed, and defective demolding can be suppressed. As a result, the maintenance frequency of the mold device 800 can be reduced. Therefore, the time and man-hours required until the start of mass production of the molded product can be reduced. Also, the amount of molding material used can be reduced.

[0130] During the process of repeatedly manufacturing the molded product by the injection molding machine 10, it is preferable that the temperature regulator control unit 713 performs control to lower the set temperature T1ref of the temperature regulator 830 from the first set temperature T1ref_start to the second set temperature T1ref_final. The first set temperature T1ref_start is higher than the second set temperature T1ref_final (T1ref_start > T1ref_final) and higher than the dew point temperature DP (T1ref_start > DP). The second set temperature T1ref_final may be lower than the ambient temperature T0 of the injection molding machine 10 (T1ref_final < T0), and may also be less than or equal to the dew point temperature DP (T1ref_final ≤ DP). Usually, DP is less than T0.

[0131] According to the present embodiment, during the process of repeatedly manufacturing the molded product by the injection molding machine 10 and the temperature T2 of the cavity surface of the mold device 800 gradually rising, the temperature regulator control unit 713 performs control to lower the set temperature T1ref of the temperature regulator 830 from the first set temperature T1ref_start to the second set temperature T1ref_final. Thereby, it is possible to suppress the temperature T2 of the cavity surface of the mold device 800 from dropping below the dew point temperature DP until the mold device 800 is sufficiently heated by the heat of the molding material. And when the temperature of the cavity surface stabilizes, the temperature T2 of the cavity surface finally reaches a temperature at which the molding material can be cured.

[0132] In addition, a specific example of the control in which the temperature regulator control unit 713 lowers the set temperature T1ref of the temperature regulator 830 from the first set temperature T1ref_start to the second set temperature T1ref_final will be described later.

[0133] Next, with reference to Figure 6 , an example of the process implemented by the control device 700 will be described. When starting the injection molding machine 10, Figure 6The processing shown below. First, the first acquisition unit 711 acquires the temperature T0 and humidity H0 of the surrounding environment of the injection molding machine 10, and the temperature regulator control unit 713 acquires the second set temperature T1ref_final (step S101). The second set temperature T1ref_final is input to the operation device 750, for example.

[0134] Next, the estimation unit 712 estimates the dew point temperature DP of the cavity surface of the mold device 800 based on the temperature T0 and humidity H0 acquired by the first acquisition unit 711 (step S102). Then, the temperature regulator control unit 713 calculates a candidate for the first set temperature T1ref_start based on the dew point temperature DP. For example, the candidate for the first set temperature T1ref_start may be only a preset amount (e.g., 10 °C) higher than the dew point temperature DP.

[0135] Next, the display control unit 715 performs control to display the dew point temperature DP and the candidate for the first set temperature T1ref_start on the display device 760 (step S103). The display control unit 715 may also perform control to display at least one of the temperature T0 and humidity H0 of the surrounding environment of the injection molding machine 10, the temperature T1 of the temperature regulator 830, and the temperature T2 of the cavity surface of the mold device 800 on the display device 760.

[0136] Next, the temperature regulator control unit 713 determines the first set temperature T1ref_start (step S104). The first set temperature T1ref_start may be (A) a temperature calculated in advance by the temperature regulator control unit 713 (e.g., a temperature that is only a preset amount higher than the dew point temperature DP), or (B) a temperature input to the operation device 750 by the user of the injection molding machine 10 while watching the display on the display device 760 (e.g., the dew point temperature DP, etc.). In addition, the user of the injection molding machine 10 can use the operation device 750 to pre-select whether to automatically determine the first set temperature T1ref_start or manually determine the first set temperature T1ref_start.

[0137] Next, the temperature regulator control unit 713 starts to control the temperature regulator 830 (step S105). The temperature regulator 830 performs feedback control on the temperature T1 of the temperature regulator 830 such that the temperature T1 of the temperature regulating medium is consistent with the first set temperature T1ref_start, for example. After step S105, the temperature regulator control unit 713 checks whether the temperature T1 of the temperature regulator 830 is consistent with the first set temperature T1ref_start (step S106). Step S106 is repeated until the temperature T1 of the temperature regulator 830 is consistent with the first set temperature T1ref_start. In addition, the temperature T1 of the temperature regulator 830 only needs to be consistent with the first set temperature T1ref_start within the error range.

[0138] When the temperature T1 of the temperature regulator 830 is consistent with the first set temperature T1ref_start (being "Yes" in step S106), the temperature of the cavity surface of the mold device 800 reaches the desired temperature, and the molding material can be cured inside the mold device 800. Therefore, the injection molding machine 10 performs a trial run, and the temperature regulator control unit 713 performs control to lower the set temperature T1ref of the temperature regulator 830 (step S107). The trial run, similar to the mass production operation, includes steps of repeatedly manufacturing molded products. The detailed content of step S107 will be described later.

[0139] In addition, when the temperature T1 of the temperature regulator 830 is consistent with the first set temperature T1ref_start (being "Yes" in step S106), the control device 700 can perform control to notify that the preparation for the trial run has been completed. When the user inputs a specified command in the operation device 750, the control device 700 can start the trial run. The molding conditions in the trial run and the molding conditions in the mass production operation can be the same or different. The molded products obtained during the trial run are basically scrapped, but the molded products that pass the inspection can also be adopted as products.

[0140] Next, the temperature regulator control unit 713 checks whether the set temperature T1ref of the temperature regulator 830 is consistent with the second set temperature T1ref_final (step S108). Step S107 is repeated until the set temperature T1ref of the temperature regulator 830 is consistent with the second set temperature T1ref_final.

[0141] When the set temperature T1ref of the temperature regulator 830 coincides with the second set temperature T1ref_final (Yes in step S108), the temperature of the cavity surface of the mold device 800 finally stabilizes at the target temperature. Then, the injection molding machine 10 performs mass production operation (step S109). Details of step S109 will be described later.

[0142] In addition, when the set temperature T1ref of the temperature regulator 830 coincides with the second set temperature T1ref_final (Yes in step S108), the control device 700 can perform control to notify that the preparation for mass production operation has been completed. When the user inputs a prescribed command in the operation device 750, the control device 700 can start mass production operation.

[0143] Next, referring to Figure 7 , a flowchart showing an example of the process performed in S107 will be described. The process shown in Figure 7 is repeated until the set temperature T1ref of the temperature regulator 830 coincides with the second set temperature T1ref_final. First, the temperature regulator control unit 713 checks whether the temperature T2 of the cavity surface of the mold device 800 is higher than the dew point temperature DP (step S201).

[0144] The temperature T2 of the cavity surface of the mold device 800 is acquired by the mold temperature sensor 840 (refer to Figure 3 ). When the mold is opened, the mold temperature sensor 840 detects the temperature T2 of the cavity surface of the mold device 800. The mold temperature sensor 840 can be a contact type or a non-contact type. As an example of a non-contact temperature sensor, a radiation temperature sensor can be cited. The mold temperature sensor 840 can be fixed to the mold device 800 by a magnet or the like. The mold temperature sensor 840 detects the temperature T2 of the cavity surface and transmits an electric signal indicating the detection result to the second acquisition unit 714.

[0145] When the temperature T2 of the cavity surface of the mold device 800 is below the dew point temperature DP (No in step S201), since dew condensation occurs on the cavity surface, the control device 700 performs control to notify a warning and performs control to stop the molding operation of the injection molding machine 10 (step S206). In addition, instead of stopping the molding operation, only a warning may be notified. The warning is notified by displaying an image, outputting a sound, or outputting an alarm or the like. The user who receives the alarm can select whether to stop the molding operation of the injection molding machine 10.

[0146] When the temperature T2 of the cavity surface of the mold device 800 is higher than the dew point temperature DP (Yes in step S201), it is checked whether the set temperature T1ref of the temperature regulator 830 is higher than the second set temperature T1ref_final (step S202). When the set temperature T1ref of the temperature regulator 830 is the same as the second set temperature T1ref_final (No in step S202), since there is no need to lower the set temperature T1ref of the temperature regulator 830, the temperature regulator control unit 713 maintains the set temperature T1ref of the temperature regulator 830 (step S205).

[0147] When the set temperature T1ref of the temperature regulator 830 is higher than the second set temperature T1ref_final (Yes in step S202), since there is room to lower the set temperature T1ref of the temperature regulator 830, it is checked whether the temperature difference ΔT1 between the past and current temperatures of the temperature regulator 830 is below the threshold value ΔT1th (step S203). Here, ΔT1 is the difference between the past temperature T1 and the current temperature T1. The past temperature T1 and the current temperature T1 are measured, for example, with a prescribed time difference. Since it is in the control process of lowering the temperature T1, the past temperature T1 is usually higher than the current temperature T1. In addition, ΔT1 can also be an absolute value.

[0148] When ΔT1 is greater than the threshold value ΔT1th (No in step S203), since the temperature T1 of the temperature regulator 830 is not stable, the temperature regulator control unit 713 maintains the set temperature T1ref of the temperature regulator 830 (step S205). On the other hand, when ΔT1 is below the threshold value ΔT1th (Yes in step S203), since the temperature T1 of the temperature regulator 830 is stable, the temperature regulator control unit 713 lowers the set temperature T1ref of the temperature regulator 830 (step S204).

[0149] If the set temperature T1ref of the temperature regulator 830 drops, feedback control is performed, so the temperature T1 of the temperature regulator 830 also drops. In addition, the control method is not particularly limited. For example, by correcting the deviation in the feedback control, the temperature T1 of the temperature regulator 830 can also be lowered.

[0150] As described above, during the process of the temperature regulator control unit 713 controlling to reduce the set temperature T1ref of the temperature regulator 830 from the first set temperature T1ref_start to the second set temperature T1ref_final, it checks whether at least one (all in this embodiment) of the following (1) to (3) holds. When at least one (all in this embodiment) of the following (1) to (3) holds, the temperature regulator control unit 713 reduces the set temperature T1ref of the temperature regulator 830.

[0151] (1) The cavity surface temperature T2 of the mold device 800 is higher than the dew point temperature DP (Yes in step S201). (2) The set temperature T1ref of the temperature regulator 830 is higher than the second set temperature T1ref_final (Yes in step S202). (3) The temperature difference ΔT1 between the past and current temperatures of the temperature regulator 830 is below the threshold value ΔT1th (Yes in step S203).

[0152] When at least one (all in this embodiment) of the above (1) to (3) holds, the temperature regulator control unit 713 reduces the set temperature T1ref of the temperature regulator 830. Thereby, regardless of the user proficiency of the injection molding machine 10, the set temperature T1ref of the temperature regulator 830 can be appropriately reduced from the first set temperature T1ref_start to the second set temperature T1ref_final automatically.

[0153] Next, with reference to Figure 8 , a flowchart showing an example of the process performed in S109 will be described. For example, during mass production operation, the process shown in Figure 8 is repeated until the production quantity of the molded product reaches the target value. First, the temperature regulator control unit 713 checks whether the temperature T2 of the cavity surface of the mold device 800 is higher than the dew point temperature DP (step S301).

[0154] When the temperature T2 of the cavity surface of the mold device 800 is below the dew point temperature DP (No in step S301), since dew condensation occurs on the cavity surface, the control device 700 performs control to notify a warning and control to stop the molding operation of the injection molding machine 10 (step S303). Additionally, instead of stopping the molding operation, only a warning can be notified.

[0155] When the temperature T2 of the cavity surface of the mold device 800 is higher than the dew point temperature DP (Yes in step S301), since no dew condensation occurs on the cavity surface, the control device 700 performs control to continue the molding operation of the injection molding machine 10 (step S302).

[0156] According to this embodiment, the control device 700 monitors whether the temperature T2 of the cavity surface is higher than the dew point temperature DP during mass production operation. Thereby, it is possible to suppress the repeated production of defective products in a state where dew condensation occurs on the cavity surface and ejection failure occurs during mass production operation. Further, when dew condensation occurs on the cavity surface during mass production operation, it is possible to promptly perform maintenance of the mold device 800.

[0157] As described above, embodiments of the control device, injection molding machine, and control method of the injection molding machine according to the present invention have been described, but the present invention is not limited to the above embodiments and the like. Various changes, corrections, substitutions, additions, deletions, and combinations can be made within the scope described in the technical solution. Of course, these also fall within the technical scope of the present invention.

Claims

1. A control device for an injection molding machine, which is a control device for an injection molding machine for filling a molding material into a cavity space inside a mold device, and which comprises: a temperature regulator control unit that controls a temperature regulator that regulates the temperature of the mold device, The temperature regulator control unit controls the temperature regulator according to a dew point temperature of a surface of the mold device forming the cavity space.

2. The control device for an injection molding machine according to claim 1, comprising: A first acquisition unit that acquires the temperature and humidity of the surrounding environment of the injection molding machine; and an estimating unit that estimates the dew point temperature of the surface of the mold device based on the temperature and humidity acquired by the first acquiring unit, The temperature regulator control unit controls the temperature regulator based on the dew point temperature estimated by the estimation unit.

3. The control device for an injection molding machine according to claim 1 or 2, wherein: The temperature regulator control unit controls the temperature regulator to decrease the set temperature from the first set temperature to the second set temperature while the injection molding machine repeatedly manufactures the molded product. The first set temperature is higher than the second set temperature and higher than the dew point temperature, The second set temperature is lower than the temperature of the surrounding environment of the injection molding machine.

4. The control device for an injection molding machine according to claim 3, wherein: The control device includes a second acquisition unit, and the second acquisition unit acquires the temperature of the surface of the mold device. The temperature regulator control unit performs control to lower a set temperature of the temperature regulator when the temperature of the surface of the mold device is higher than the dew point temperature.

5. The control device for an injection molding machine according to claim 3, wherein: The temperature regulator control unit performs control to lower the set temperature of the temperature regulator when the set temperature of the temperature regulator is higher than the second set temperature.

6. The control device for an injection molding machine according to claim 3, wherein: The temperature regulator control unit performs control to lower the set temperature of the temperature regulator when the difference between the past and the present temperature of the temperature regulator is equal to or smaller than a threshold value.

7. An injection molding machine, wherein: A control device according to claim 1 or 2.

8. A method for controlling an injection molding machine, which is a method for controlling an injection molding machine for filling a molding material into a cavity space inside a mold device, wherein: The control method of the injection molding machine controls a temperature regulator that regulates the temperature of the mold device, The temperature regulator is controlled according to the dew point temperature of the surface of the mold device forming the cavity space.

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