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

Abstract

The invention relates to 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 capable of simply and properly adjusting cold start prevention time. The control device is a control device of an injection molding machine, and the injection molding machine is provided with: an injection part which injects a molding material from a cylinder to a mold device; and a drive source that operates the injection member. The control device is provided with a cold prevention starting part, and when a first condition is satisfied, the cold prevention starting part performs control for restricting the operation of the injection part for a preset cold prevention starting time period. In order to determine whether or not a value shorter than an initial value should be used as the cold start prevention time, the cold start prevention unit determines whether or not a second condition different from the first condition is satisfied even if the first condition is satisfied.

Description

Technical Field

[0001] This application claims priority based on Japanese Patent Application No. 2023-097825 filed on June 14, 2023. The entire contents of the Japanese Patent Application are incorporated herein by reference.

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

[0003] The injection molding machine has an injection component for injecting the molding material from the cylinder to the mold device and a driving source for actuating the injection component. The injection component is arranged inside the cylinder. The injection component is, for example, a screw. The molding material is, for example, a resin. The molding material is melted inside the cylinder and then injected from the cylinder to the mold device.

[0004] The injection molding machine is equipped with a heater for heating the cylinder and a temperature detector for detecting the actual temperature of the cylinder. The injection molding machine controls the heater so that the actual temperature of the cylinder becomes a set temperature. The set temperature of the cylinder is prepared for each operation mode of the injection molding machine.

[0005] The operation mode of the injection molding machine includes, for example, a molding mode and a heat-keeping mode. In the molding mode, the molding material is injected from the cylinder into the mold device. In the heat-keeping mode, the operation of the injection part is stopped at night or on weekends. In the heat-keeping mode, in order to suppress carbonization of the molding material, the temperature of the cylinder is set lower than that in the molding mode.

[0006] The operation mode of the injection molding machine may also include a purge mode. In the purge mode, for example, after the insulation mode and before the molding mode, the molding material in the cylinder is injected to the outside of the mold device, thereby replacing the molding material in the cylinder. In the purge mode, the temperature of the cylinder is set lower than that in the molding mode.

[0007] The control device of the injection molding machine sometimes raises the temperature of the cylinder. For example, when the set temperature for the molding mode is changed to a higher level during the molding mode, when the operation mode of the injection molding machine is switched from the keep-warm mode or the purge mode to the molding mode, or when the power supply to the heater is cut off due to a power outage or an operating error and then resumed, the cylinder is heated up.

[0008] If the temperature of the cylinder increases greatly, there will be a time lag from the completion of the temperature increase of the cylinder to the completion of the temperature increase of the molding material in the cylinder. If the drive source causes the injection component to move before the molding material in the cylinder is fully heated, an excessive load will be applied to the injection component, and the injection component may be damaged. In addition, molding defects may occur.

[0009] Therefore, the control device of the injection molding machine performs the following control: before the molding material in the cylinder is sufficiently heated, the movement of the injection component is restricted. The control to restrict the movement of the injection component is called cold start prevention. And the time for performing cold start prevention is called cold start prevention time. The cold start prevention time is set in advance through experiments, etc., so that the molding material in the cylinder is sufficiently heated.

[0010] However, if the temperature rise of the cylinder is small, the molding material in the cylinder has been fully heated. In this case, if the action of the injection component is also restricted during the initial cold start protection time, time will be wasted until the molded product is restarted.

[0011] Patent Document 1 discloses a technique in which, if the stop time from when the injection molding machine stops to when it resumes operation is within a certain time, an injection component is enabled to operate according to the type of resin and the stop time.

[0012] Patent Document 1: Japanese Patent Application Laid-Open No. 11-170327

[0013] As described in Patent Document 1, the control corresponding to the type of resin requires the preparation of a complex calculation program that matches the resin characteristics, and requires special electrical components for implementing the calculation program. In addition, it is required to input information related to the resin characteristics before the injection molding machine is operated, which increases the burden on the operator. In particular, when the frequency of changing the type of resin is high, the burden on the operator increases. Summary of the invention

[0014] One embodiment of the present invention provides a technology for simply and appropriately adjusting the cold start prevention time.

[0015] A control device according to one embodiment of the present invention is a control device for an injection molding machine, the injection molding machine comprising an injection component for injecting a molding material from a cylinder into a mold device and a drive source for operating the injection component. The control device comprises a cold start prevention unit, and when a first condition is satisfied, the cold start prevention unit controls the operation of the injection component to be limited during a preset cold start prevention time. In order to determine whether a value shorter than an initial value should be used as the cold start prevention time, the cold start prevention unit determines whether a second condition different from the first condition is satisfied even when the first condition is satisfied.

[0016] Effects of the Invention

[0017] According to one aspect of the present invention, the cold start prevention time can be adjusted simply and appropriately. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1This is a diagram showing a state of the injection molding machine according to one embodiment when mold opening is completed.

[0019] Figure 2 It is a diagram showing a state of the injection molding machine according to one embodiment when the mold is clamped.

[0020] Figure 3 This is a diagram showing an example of constituent elements of a control device using functional blocks.

[0021] Figure 4 This is a diagram showing an example of the process of the molding cycle.

[0022] Figure 5 This is a flowchart showing an example of the processing of the cold start prevention unit.

[0023] Explanation of symbols

[0024] 10-injection molding machine, 310-cylinder body, 330-screw (injection component), 340-metering motor (drive source), 350-injection motor (drive source), 700-control device, 716-anti-cold start unit, 800-mold device. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in each of the drawings, the same or corresponding structures are sometimes denoted by the same reference numerals, and the description thereof is omitted.

[0026] (Injection Molding Machine)

[0027] Figure 1 This is a diagram showing a state of the injection molding machine according to one embodiment when mold opening is completed. Figure 2 1 is a diagram showing a state of an injection molding machine involved in an embodiment when the mold is clamped. In this specification, the X-axis direction, the Y-axis direction and the Z-axis direction are directions perpendicular to each other. The X-axis direction and the Y-axis direction represent horizontal directions, and the Z-axis direction represents a vertical direction. When the clamping device 100 is horizontal, the X-axis direction is the mold opening and closing direction, and the Y-axis direction is the width direction of the injection molding machine 10. The negative side of the Y-axis direction is called the operating side, and the positive side of the Y-axis direction is called the opposite side of the operating side.

[0028] like Figure 1-2As shown, the injection molding machine 10 includes: a mold clamping device 100 for opening and closing a mold device 800; an ejection device 200 for ejecting a molded product molded 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 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 installed on the floor 2 via a level adjuster 930. The control device 700 is arranged in the internal space of the injection device frame 920. Hereinafter, each component of the injection molding machine 10 will be described.

[0029] (Mold clamping device)

[0030] In the description of the mold clamping device 100, the moving direction of the movable platen 120 when the mold is closed (for example, the positive direction of the X axis) is set to the front, and the moving direction of the movable platen 120 when the mold is opened (for example, the negative direction of the X axis) is set to the rear.

[0031] The mold clamping device 100 performs mold closing, pressure increase, mold clamping, pressure reduction, and mold opening of the mold device 800. The mold device 800 includes a fixed mold 810 and a movable mold 820.

[0032] The mold clamping device 100 is, for example, horizontal, and has a fixed platen 110 to which the fixed mold 810 is mounted, a movable platen 120 to which the movable mold 820 is mounted, and a moving mechanism 102 to move the movable platen 120 relative to the fixed platen 110 in the mold opening and closing direction.

[0033] The fixed platen 110 is fixed to the mold clamping device frame 910. The fixed mold 810 is mounted on the surface of the fixed platen 110 that faces the movable platen 120.

[0034] The movable platen 120 is arranged to be movable in the mold opening and closing direction relative to the mold clamping device frame 910. A guide 101 for guiding the movable platen 120 is laid on the mold clamping device frame 910. The movable mold 820 is mounted on the surface of the movable platen 120 facing the fixed platen 110.

[0035] The moving mechanism 102 closes the mold, increases the pressure, clamps the mold, reduces the pressure, and opens the mold 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, which is arranged with a gap between the fixed platen 110; a connecting rod 140, which connects the fixed platen 110 and the toggle seat 130; a toggle mechanism 150, which moves the movable platen 120 relative to the toggle seat 130 in the mold opening and closing direction; a mold clamping motor 160, which operates the toggle mechanism 150; a motion conversion mechanism 170, which converts the rotational motion of the mold clamping motor 160 into a linear motion; and a mold thickness adjustment mechanism 180, which adjusts the gap between the fixed platen 110 and the toggle seat 130.

[0036] The toggle seat 130 is arranged with a gap between the fixed platen 110 and is placed on the mold clamping device frame 910 so as to be movable in the mold opening and closing direction. In addition, the toggle seat 130 can be arranged so as to be movable along a guide member laid on the mold clamping device frame 910. The guide member of the toggle seat 130 can be common to the guide member 101 of the movable platen 120.

[0037] In addition, in the present embodiment, the fixed pressure plate 110 is fixed to the mold clamping device frame 910, and the elbow seat 130 is configured to be freely movable relative to the mold clamping device frame 910 in the mold opening and closing direction. However, the elbow seat 130 may also be fixed to the mold clamping device frame 910, and the fixed pressure plate 110 may be configured to be freely movable relative to the mold clamping device frame 910 in the mold opening and closing direction.

[0038] The connecting rod 140 connects the fixed platen 110 and the toggle seat 130 at a distance L in the mold opening and closing direction. A plurality of connecting rods 140 (for example, four) may be used. The plurality of connecting rods 140 are arranged 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 may be provided on at least one of the connecting rods 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 mold clamping force, etc.

[0039] In addition, in this embodiment, the tie 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 to this. The mold clamping force detector is not limited to the strain type, and can also be a piezoelectric type, a capacitive type, a hydraulic type, an electromagnetic type, etc., and its installation position is not limited to the tie rod 140.

[0040] The toggle mechanism 150 is disposed between the movable platen 120 and the toggle seat 130, and moves the movable platen 120 in the mold opening and closing direction relative to the toggle seat 130. The toggle mechanism 150 includes a crosshead 151 that moves in the mold opening and closing direction and a pair of link groups that are bent and extended by the movement of the crosshead 151. The pair of link groups each includes a first link 152 and a second link 153 that are connected by a pin or the like so as to be able to bend and extend freely. The first link 152 is mounted by a pin or the like so as to be able to swing freely relative to the movable platen 120. The second link 153 is mounted by a pin or the like so as to be able to swing freely relative to the toggle seat 130. The second link 153 is mounted to the crosshead 151 via a third link 154. When the crosshead 151 is moved forward and backward relative to the toggle seat 130, the first link 152 and the second link 153 are bent and extended, and the movable platen 120 moves forward and backward relative to the toggle seat 130.

[0041] In addition, the structure of the toggle mechanism 150 is not limited to Figure 1 and Figure 2 For example, in Figure 1 and Figure 2 In the embodiment, the number of nodes of each link group is five, but may be four, or one end of the third link 154 may be connected to a node between the first link 152 and the second link 153 .

[0042] The mold clamping motor 160 is mounted on the toggle base 130 to operate the toggle mechanism 150. The mold clamping motor 160 causes the cross head 151 to move forward and backward relative to the toggle base 130, thereby bending and extending the first link 152 and the second link 153, thereby moving the movable platen 120 forward and backward relative to the toggle base 130. The mold clamping motor 160 is directly connected to the motion conversion mechanism 170, but may also be connected to the motion conversion mechanism 170 via a belt, a pulley, or the like.

[0043] The motion conversion mechanism 170 converts the rotational motion of the mold clamping motor 160 into the linear motion of the cross head 151. The motion conversion mechanism 170 includes a screw shaft and a screw nut screwed with the screw shaft. Balls or rollers may be interposed between the screw shaft and the screw nut.

[0044] The mold clamping device 100 performs a mold closing process, a pressure increasing process, a mold clamping process, a pressure reducing process, a mold opening process, and the like under the control of the control device 700 .

[0045] In the mold closing process, the mold clamping motor 160 is driven to move the crosshead 151 to the mold closing completion position at a set moving speed, and the movable platen 120 is moved forward, so that the movable mold 820 contacts the fixed mold 810. For example, the position and moving speed of the crosshead 151 are detected using a mold clamping motor encoder 161. The mold clamping motor encoder 161 detects the rotation of the mold clamping motor 160 and sends a signal indicating the detection result to the control device 700.

[0046] 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 mold clamping motor encoder 161, and a conventional detector may be used. Furthermore, 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 mold clamping motor encoder 161, and a conventional detector may be used.

[0047] In the pressure increasing step, the mold clamping motor 160 is further driven to cause the cross head 151 to further move forward from the mold closing completion position to the mold clamping position, thereby generating a mold clamping force.

[0048] In the mold clamping process, the mold clamping motor 160 is driven to maintain the position of the crosshead 151 at the mold clamping position. In the mold clamping process, the mold clamping force generated in the pressure increasing 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 ), the injection device 300 fills the liquid molding material into the cavity space 801. The filled molding material is solidified to obtain a molded product.

[0049] The number of cavity spaces 801 may be one or more. In the latter case, multiple molded products can be obtained at the same time. An insert may be arranged in a part of the cavity space 801, and a molding material may 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.

[0050] In the decompression step, the mold clamping motor 160 is driven to retract the crosshead 151 from the mold clamping position to the mold opening start position to retract the movable platen 120, thereby reducing the mold clamping force. The mold opening start position and the mold closing completion position may be the same position.

[0051] In the mold opening process, the mold clamping motor 160 is driven to move the crosshead 151 from the mold opening start position to the mold opening completion position at a set moving speed to move the movable platen 120 backward, thereby separating the movable mold 820 from the fixed mold 810. Then, the ejector device 200 ejects the molded product from the movable mold 820.

[0052] The setting conditions in the mold closing process, the pressure increasing process and the mold clamping process are set together as a series of setting conditions. For example, the moving speed, position (including the mold closing start position, the moving speed switching position, the mold closing completion position and the mold clamping position) and the mold clamping force of the crosshead 151 in the mold closing process and the pressure increasing process are set together as a series of setting conditions. The mold closing start position, the moving speed switching position, the mold closing completion position and the mold clamping position are arranged in sequence from the back to the front, and indicate the starting point and end point of the interval for setting the moving speed. The moving speed is set for each interval. The moving speed switching position can be one or more. The moving speed switching position can also be not set. Only one of the mold clamping position and the mold clamping force can be set.

[0053] The setting conditions in the decompression process and the 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 decompression process and the mold opening process are set together as a series of setting conditions. The mold opening start position, the moving speed switching position and the mold opening completion position are arranged in sequence from the front to the back, and represent the starting point and end point of the interval for setting the moving speed. The moving speed is set for each interval. The moving speed switching position can be one or more. The moving speed switching position can also be not set. The mold opening start position and the mold closing completion position can be the same position. In addition, the mold opening completion position and the mold closing start position can be the same position.

[0054] Alternatively, the moving speed and position of the movable platen 120 may be set instead of the moving speed and position of the crosshead 151. Furthermore, the mold clamping force may be set instead of the position of the crosshead (eg, mold clamping position) and the position of the movable platen.

[0055] However, the toggle mechanism 150 amplifies the driving force of the mold clamping motor 160 and transmits it to the movable platen 120. The amplification factor is also called the toggle magnification. The toggle magnification changes according to 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 calculated according to the position of the crosshead 151. When the link angle θ is 180°, the toggle magnification is maximum.

[0056] 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 predetermined mold clamping force when the mold is clamped. 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 predetermined angle at the time of mold contact between the movable mold 820 and the fixed mold 810.

[0057] The mold clamping device 100 has a mold thickness adjustment mechanism 180. The mold thickness adjustment mechanism 180 adjusts the mold thickness by adjusting the interval L between the fixed platen 110 and the toggle seat 130. In addition, regarding the timing of mold thickness adjustment, it 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 has, for example: a screw shaft 181 formed at the rear end of the connecting rod 140; a screw nut 182 that is held on the toggle seat 130 so as to be rotatable and unable to move forward and backward; and a mold thickness adjustment motor 183 that rotates the screw nut 182 that is threaded with the screw shaft 181.

[0058] A screw shaft 181 and a 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 the plurality of screw nuts 182 via the rotational driving force transmission unit 185. The plurality of screw nuts 182 can be rotated synchronously. In addition, the plurality of screw nuts 182 can be rotated individually by changing the transmission path of the rotational driving force transmission unit 185.

[0059] The rotational driving force transmission part 185 is composed of, for example, gears. In this case, 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 held rotatably at the center of the toggle seat 130. In addition, the rotational driving force transmission part 185 may be composed of a belt, a pulley, etc. instead of a gear.

[0060] The operation of the mold thickness adjustment mechanism 180 is controlled by the control device 700. The control device 700 drives the mold thickness adjustment motor 183 to rotate the 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 adjustment mechanisms may be used in combination.

[0061] The mold thickness adjustment motor encoder 184 is used to detect the interval L. 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 to monitor and control 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 a conventional detector can be used.

[0062] The mold clamping device 100 may include a mold temperature regulator for regulating the temperature of the mold device 800. The mold device 800 includes a flow path of a temperature regulating medium therein. The mold temperature regulator regulates the temperature of the mold device 800 by regulating the temperature of the temperature regulating medium supplied to the flow path of the mold device 800.

[0063] Furthermore, the mold clamping device 100 of the present embodiment is a horizontal type in which the mold opening and closing direction is the horizontal direction, but may be a vertical type in which the mold opening and closing direction is the vertical direction.

[0064] The mold clamping device 100 of this embodiment includes the mold clamping motor 160 as a driving unit, but may include a hydraulic cylinder instead of the mold clamping motor 160. Furthermore, the mold clamping device 100 may include a linear motor for mold opening and closing, and may include an electromagnet for mold clamping.

[0065] (Ejector device)

[0066] In the description of the ejection device 200, similar to the description of the mold clamping device 100, the moving direction of the movable platen 120 when the mold is closed (for example, the positive direction of the X-axis) is set to the front and the moving direction of the movable platen 120 when the mold is opened (for example, the negative direction of the X-axis) is set to the rear.

[0067] The ejector device 200 is mounted on the movable platen 120 and moves forward and backward together with the movable platen 120. The ejector device 200 includes an ejector rod 210 for ejecting the molded product from the mold device 800 and a drive mechanism 220 for moving the ejector rod 210 along the moving direction of the movable platen 120 (X-axis direction).

[0068] The ejector rod 210 is configured to be able to move forward and backward in the through hole of the movable platen 120. The front end of the ejector rod 210 contacts the ejector plate 826 of the movable mold 820. The front end of the ejector rod 210 may be connected to the ejector plate 826 or may not be connected thereto.

[0069] The driving mechanism 220 includes, for example, an ejector motor and a motion conversion mechanism that converts the rotational motion of the ejector motor into the linear motion of the ejector rod 210. The motion conversion mechanism includes a screw shaft and a screw nut screwed with the screw shaft. Balls or rollers may be interposed between the screw shaft and the screw nut.

[0070] The ejector device 200 performs an 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 moving speed to advance the ejector plate 826, 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 moved backward to the original standby position.

[0071] For example, an ejector motor encoder is used to detect the position and moving speed of the ejector rod 210. The ejector motor encoder detects the rotation of the ejector motor and sends a signal indicating the 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 moving speed detector for detecting the moving speed of the ejector rod 210 are not limited to the ejector motor encoder, and a conventional detector can be used.

[0072] (Injection device)

[0073] 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 moving direction of the screw 330 during filling (for example, the negative direction of the X-axis) is set to the front and the moving direction of the screw 330 during metering (for example, the positive direction of the X-axis) is set to the rear.

[0074] The injection device 300 is provided on a sliding base 301, and the sliding base 301 is configured to be able to move forward and backward freely relative to the injection device frame 920. The injection device 300 is configured to be able to move forward and backward freely relative to the mold device 800. The injection device 300 contacts the mold device 800 and fills the molding material into the cavity space 801 in the mold device 800. The injection device 300 includes, for example: a cylinder 310 for heating the molding material; a nozzle 320 provided at the front end of the cylinder 310; a screw 330 configured to be able to move forward and backward freely and to rotate freely in 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.

[0075] The cylinder 310 heats the molding material supplied from the supply port 311. The molding material includes, for example, resin. The molding material is formed into, for example, granules and supplied to the supply port 311 in a solid state. The supply port 311 is formed at the rear of the cylinder 310. A cooler 312 such as a water-cooled cylinder is provided on the outer periphery of the rear of the cylinder 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 310 in front of the cooler 312.

[0076] The cylinder 310 is divided into a plurality of regions along the axial direction (e.g., the X-axis direction) of the cylinder 310. A first heater 313 and a first temperature detector 314 are respectively provided in the plurality of regions. 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 detection temperature of the first temperature detector 314 becomes the set temperature.

[0077] The nozzle 320 is provided at the front end of the cylinder 310 and is pressed by 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 a set temperature.

[0078] The screw 330 is configured to be able to rotate freely and to move forward and backward freely in the cylinder 310. When the screw 330 is rotated, the molding material is transported forward along the spiral groove of the screw 330. While the molding material is transported forward, it is gradually melted by the heat from the cylinder 310. As the liquid molding material is transported forward to the front of the screw 330 and accumulated in the front part of the cylinder 310, the screw 330 is retracted. Then, when the screw 330 is advanced, the liquid molding material accumulated in front of the screw 330 is injected from the nozzle 320 and filled in the mold device 800.

[0079] A check ring 331 is installed at the front of the screw 330 so as to be able to move forward and backward. The check ring 331 serves as a check valve to prevent the molding material from flowing backward from the front to the rear of the screw 330 when the screw 330 is pushed forward.

[0080] 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 retreats relatively to the screw 330 to a closed position that blocks the flow path of the molding material (see FIG. Figure 2 ). Thus, the molding material accumulated in front of the screw 330 is prevented from flowing backward.

[0081] 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 to the front along the spiral groove of the screw 330, and moves forward relative to the screw 330 to an open position (refer to Figure 1 ). As a result, the molding material is transported to the front of the screw 330.

[0082] The check ring 331 may be 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 .

[0083] In addition, the injection device 300 may include a driving source that moves the check ring 331 forward and backward relative to the screw 330 between the open position and the closed position.

[0084] The metering motor 340 rotates the screw 330. The driving source for rotating the screw 330 is not limited to the metering motor 340, and may be, for example, a hydraulic pump or the like.

[0085] The injection motor 350 moves the screw 330 forward and backward. A motion conversion mechanism that 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 includes, for example, a screw shaft and a screw nut screwed with the screw shaft. Balls and rollers may be provided between the screw shaft and the screw nut. The driving source that moves the screw 330 forward and backward is not limited to the injection motor 350, and may be, for example, a hydraulic cylinder.

[0086] 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 transmission path of the load between the injection motor 350 and the screw 330, and detects the load acting on the load detector 360.

[0087] The load detector 360 sends a signal of the detected load to the control device 700. The load detected by the load detector 360 is converted into a pressure acting between the screw 330 and the molding material, and is used to control and monitor the pressure on the screw 330 from the molding material, the back pressure of the screw 330, the pressure acting from the screw 330 to the molding material, and the like.

[0088] In addition, the pressure detector for detecting the pressure of the molding material is not limited to the load detector 360, and a conventional detector can be used. For example, a nozzle pressure sensor or a mold internal pressure sensor can be used. The nozzle pressure sensor is provided at the nozzle 320. The mold internal pressure sensor is provided inside the mold device 800.

[0089] The injection device 300 performs a metering process, a filling process, a pressure-maintaining process, etc. under the control of the control device 700. The filling process and the pressure-maintaining process can be collectively referred to as an injection process.

[0090] 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 transported to the front along the spiral groove of the screw 330. As a result, the molding material is gradually melted. As the liquid molding material is transported to the front of the screw 330 and accumulated in the front part of the cylinder 310, the screw 330 is retracted. For example, the rotation speed of the screw 330 is detected using a metering motor encoder 341. 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. In addition, the screw speed detector that detects the rotation speed of the screw 330 is not limited to the metering motor encoder 341, and a conventional detector can be used.

[0091] In order to prevent the screw 330 from retreating rapidly during the metering process, the injection motor 350 may be driven to apply a set back pressure to the screw 330. For example, the back pressure on the screw 330 is detected using the load detector 360. When the screw 330 retreats to the metering completion position and a predetermined amount of molding material is accumulated in front of the screw 330, the metering process is completed.

[0092] The position and speed of the screw 330 in the metering process are set as a series of setting conditions. For example, the metering start position, the speed switching position and the metering completion position are set. These positions are arranged in sequence from the front to the back, and represent the starting point and the end point of the interval for setting the speed. The speed is set for each interval. The speed switching position can be one or more. The speed switching position can also be not set. In addition, the back pressure is set for each interval.

[0093] In the filling process, the injection motor 350 is driven to make the screw 330 move forward at a set moving speed, and the liquid molding material accumulated in front of the screw 330 is filled into the cavity space 801 in the mold device 800. For example, the position and moving speed of the screw 330 are detected using the injection motor encoder 351. 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 position of the screw 330 reaches the set position, the switch from the filling process to the pressure holding process (the so-called V / P switch) is performed. The position where the V / P switch is performed is also referred to as 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.

[0094] The position and moving speed of the screw 330 in the filling process are set as a series of setting 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 sequence from the back to the front, and indicate the start and end points of the interval for setting the moving speed. The moving speed is set for each interval. The moving speed switching position can be one or more. The moving speed switching position can also be not set.

[0095] The upper limit value of the pressure of the screw 330 is set for each interval of the moving speed of the screw 330. 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, the screw 330 moves forward at a moving speed slower than the set moving speed for the purpose of protecting the mold so that the pressure of the screw 330 becomes below the set pressure.

[0096] In addition, in the filling process, after the position of the screw 330 reaches the V / P switching position, the screw 330 may be temporarily stopped at the V / P switching position, and then the V / P switching may be performed. Alternatively, the screw 330 may be moved forward or backward at a slow speed instead of stopping the screw 330 just before the V / P switching. Furthermore, 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 a conventional detector may be used.

[0097] In the pressure holding process, the injection motor 350 is driven to push the screw 330 forward, the pressure of the molding material at the front end of the screw 330 (hereinafter also referred to as "holding pressure") is maintained at the set pressure, and the molding material remaining in the cylinder 310 is pushed toward the mold device 800. The insufficient amount of molding material caused by the cooling shrinkage in the mold device 800 can be supplemented. For example, the holding pressure is detected using a load detector 360. The setting value of the holding pressure can be changed according to the elapsed time from the start of the pressure holding process. The holding pressure and the holding time of the holding pressure in the pressure holding process can be set separately in multiples, or can be set together as a series of setting conditions.

[0098] In the pressure holding process, the molding material in the cavity space 801 in the mold device 800 is gradually cooled. When the pressure holding process is completed, the entrance of the cavity space 801 is blocked by the solidified molding material. This state is called gate sealing, which prevents the molding material from flowing back from the cavity space 801. After the pressure holding process, the cooling process begins. In the cooling process, the molding material in the cavity space 801 is solidified. In order to shorten the molding cycle time, a metering process can be performed in the cooling process.

[0099] In addition, the injection device 300 of the present embodiment is a coaxial screw type, but it can also be a pre-plastic type, etc. The injection device of the pre-plastic type 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 cannot move forward or backward, or the screw is configured to be rotatable and move forward and backward freely. On the other hand, in the injection cylinder, the plunger is configured to move forward and backward freely.

[0100] Furthermore, the injection device 300 of the present embodiment is a horizontal type in which the axial direction of the cylinder 310 is in the horizontal direction, but it may be a vertical type in which the axial direction of the cylinder 310 is in the up-down direction. The mold clamping device combined with the vertical injection device 300 may be a vertical type or a horizontal type. Similarly, the mold clamping device combined with the horizontal injection device 300 may be a horizontal type or a vertical type.

[0101] (Mobile device)

[0102] In the description of the moving device 400, similar to the description of the injection device 300, the moving direction of the screw 330 during filling (for example, the negative direction of the X axis) is set to the front and the moving direction of the screw 330 during metering (for example, the positive direction of the X axis) is set to the rear.

[0103] The moving device 400 moves the injection device 300 forward and backward relative to the mold device 800. The moving device 400 also presses the nozzle 320 against the mold device 800 to generate nozzle contact pressure. The moving device 400 includes a hydraulic pump 410, a motor 420 as a driving source, and a hydraulic cylinder 430 as a hydraulic actuator.

[0104] The hydraulic pump 410 has a first port 411 and a second port 412. The hydraulic pump 410 is a bidirectionally rotatable pump, and generates hydraulic pressure by sucking working fluid (e.g., oil) from one of the first port 411 and the second port 412 and discharging it from the other port by switching the rotation direction of the motor 420. Alternatively, the hydraulic pump 410 can also suck working fluid from a tank and discharge the working fluid from one of the first port 411 and the second port 412.

[0105] The motor 420 operates the hydraulic pump 410. The motor 420 drives the hydraulic pump 410 with a rotation direction and torque corresponding to a control signal from the control device 700. The motor 420 may be an electric motor or an electric servomotor.

[0106] The hydraulic cylinder 430 has a cylinder body 431, a piston 432, and a piston rod 433. The cylinder body 431 is fixed to the injection device 300. The piston 432 divides the interior of the cylinder body 431 into a front chamber 435 as a first chamber and a rear chamber 436 as a second chamber. The piston rod 433 is fixed to the fixed platen 110.

[0107] The front chamber 435 of the hydraulic cylinder 430 is connected to the first port 411 of the hydraulic pump 410 via the 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, so that the injection device 300 is pushed forward. The injection device 300 moves forward, so that the nozzle 320 is pressed against the fixed mold 810. The front chamber 435 functions as a pressure chamber that generates a nozzle contact pressure of the nozzle 320 by the pressure of the working fluid supplied from the hydraulic pump 410.

[0108] 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 hydraulic fluid discharged from the second port 412 is supplied to the rear chamber 436 of the hydraulic cylinder 430 via the second flow path 402, so that the injection device 300 is pushed backward. The injection device 300 retreats, and the nozzle 320 is separated from the fixed mold 810.

[0109] In this embodiment, the moving device 400 includes the 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 the linear motion of the injection device 300 may be used instead of the hydraulic cylinder 430 .

[0110] (Control device)

[0111] The control device 700 is constituted by a computer, for example. Figure 1-2 As shown, the control device 700 has a CPU (Central Processing Unit) 701, a storage medium such as a memory 702, 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. In addition, 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.

[0112] The control device 700 repeatedly manufactures molded products by repeatedly performing metering steps, mold closing steps, pressure increasing steps, mold clamping steps, filling steps, pressure holding steps, cooling steps, pressure reducing steps, mold opening steps, and ejection steps. A series of actions for obtaining molded products, such as the actions from the start of a metering step to the start of the next metering step, are also referred to as "injection" or "molding cycle". In addition, the time required for one injection is also referred to as "molding cycle time" or "cycle time".

[0113] A molding cycle includes, for example, a metering process, a mold closing process, a pressure increasing process, a mold closing process, a filling process, a pressure holding process, a cooling process, a decompression process, a mold opening process, and an ejection process in sequence. 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 closing process. The start of the mold closing process may also coincide with the start of the filling process. The completion of the decompression process coincides with the start of the mold opening process.

[0114] In addition, in order 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 performed at the beginning of the molding cycle. In addition, the filling process can be started during the mold closing process. In addition, the ejection process can be started during the mold opening process. When an on-off valve for opening and closing the flow path of the nozzle 320 is provided, the mold opening process can be started during the metering process. This is because, even if the mold opening process is started 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.

[0115] In addition, a primary molding cycle may include processes other than the metering process, the mold closing process, the pressure increasing process, the mold clamping process, the filling process, the pressure holding process, the cooling process, the decompression process, the mold opening process, and the ejection process.

[0116] For example, after the pressure holding process is completed and before the metering process is started, a pre-metering suction process can be performed to retract the screw 330 to a preset metering start position. The pressure of the molding material accumulated in front of the screw 330 can be reduced before the metering process is started, thereby preventing the screw 330 from retreating sharply when the metering process is started.

[0117] Furthermore, after the metering process is completed and before the filling process is started, a post-metering backsucking process may be performed to retract the screw 330 to a preset filling start position (also referred to as an "injection start position"). The pressure of the molding material accumulated in front of the screw 330 can be reduced before the filling process is started, thereby preventing the molding material from leaking from the nozzle 320 before the filling process is started.

[0118] The control device 700 is connected to an operating device 750 that receives input operations from a user and a display device 760 that displays a screen. The operating device 750 and the display device 760 may be formed of, for example, a touch panel 770 and integrated. The touch panel 770 as the display device 760 displays a screen under the control of the control device 700. On the screen of the touch panel 770, for example, information such as the settings of the injection molding machine 10 and the current state of the injection molding machine 10 may be displayed. In addition, on the screen of the touch panel 770, for example, operating parts such as buttons and input fields that receive input operations from the user may also be displayed. The touch panel 770 as the operating device 750 detects the input operation 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 operating part set on the screen while confirming the information displayed on the screen to perform settings of the injection molding machine 10 (including input of a set value), etc. In addition, by the user operating the operating part set on the screen, the injection molding machine 10 corresponding to the operating part can be operated. In addition, the operation of the injection molding machine 10 may 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. Furthermore, the operation of the injection molding machine 10 may be the switching of the screen displayed on the touch panel 770 as the display device 760, etc.

[0119] In addition, the operating device 750 and the display device 760 of this embodiment are described as being integrated into a touch panel 770, but they may be provided independently. In addition, a plurality of operating devices 750 may be provided. The operating device 750 and the display device 760 are arranged on the operating side (negative direction of the Y axis) of the mold clamping device 100 (more specifically, the fixed platen 110).

[0120] (Detailed description of control device)

[0121] Next, refer to Figure 3 An example of the components of the control device 700 is described. Figure 3 The functional blocks shown in the figure are conceptual functional blocks and do not necessarily have to be physically constructed as shown. All or part of each functional block can be functionally or physically dispersed or integrated in any unit to form a structure. All or any part of each processing function performed in each functional block can be implemented by a program executed by the CPU, or as hardware based on wired logic.

[0122] like Figure 3 As shown, the control device 700 includes, for example, a mold clamping control unit 711, an ejection control unit 712, an injection control unit 713, a metering control unit 714, a temperature control unit 715, and a cold start prevention unit 716. The mold clamping control unit 711 controls the mold clamping device 100 and implements Figure 4 The ejection control unit 712 controls the ejection device 200 and performs the ejection process.

[0123] The injection control unit 713 controls the injection drive source of the injection device 300 and implements the injection process. In this embodiment, the injection drive source is the injection motor 350, but it can also be a hydraulic cylinder or the like. Figure 4 As shown, the injection process is performed in the mold closing process. The injection control unit 713 controls the operation of the injection component. The injection component is set inside the cylinder 310, and the molding material is injected from the cylinder 310 to the mold device 800. In this embodiment, the injection component is a screw 330, but it can also be a plunger.

[0124] The injection control unit 713 monitors the actual value of the moving speed of the screw 330. The moving speed of the screw 330 is detected using a speed detector. For example, the speed detector is an injection motor encoder 351. In addition, the injection control unit 713 monitors the actual value of the pressure applied to the molding material from the screw 330. The pressure is detected using a pressure detector such as a load detector 360. As the pressure detector, a nozzle pressure sensor or a mold internal pressure sensor can be used. Figure 4 As shown, the injection process includes a filling process and a pressure holding process in sequence.

[0125] The filling process is a process of filling the liquid molding material accumulated in front of the screw 330 into the mold device 800 by moving the screw 330 forward. The filling process is, for example, a process of controlling the injection motor 350 so that the actual value of the moving speed of the screw 330 provided in the cylinder 310 becomes a set value. In the filling process, the actual value of the pressure acting on the molding material from the screw 330 increases as the screw 330 moves forward.

[0126] The pressure holding step is a step of replenishing insufficient molding material due to cooling shrinkage in the mold device 800 by pushing the screw 330 forward. The pressure holding step is a step of controlling the injection motor 350 so that the actual value of the pressure applied to the molding material from the screw 330 becomes a set value.

[0127] The metering control unit 714 controls the metering drive source of the injection device 300 and implements the metering process. In this embodiment, the metering drive source is the metering motor 340, but it can also be a hydraulic pump or the like. In order to shorten the molding cycle time, it is preferred that Figure 4 The metering process is performed in the cooling process as shown. The cooling process starts after the pressure holding process is completed. The molding material in the cavity space 801 is solidified in the cooling process.

[0128] The temperature control unit 715 controls the temperature of the cylinder 310. The cylinder 310 is divided into a plurality of regions along the axial direction (e.g., the X-axis direction) of the cylinder 310. The first heater 313 and the first temperature detector 314 are respectively provided in the plurality of regions. The first heater 313 heats the cylinder 310. The first temperature detector 314 detects the actual temperature of the cylinder 310. A set temperature is set for each of the plurality of regions.

[0129] The temperature control unit 715 detects the actual temperature of each of the plurality of regions through the first temperature detector 314, and performs feedback control on the output of the first heater 313 for each region individually so that the actual temperature detected by the first temperature detector 314 becomes the set temperature. The plurality of first heaters 313 may be of the same structure or of different structures. The first heater 313 is, for example, a belt heater. The output of the first heater 313 is, for example, expressed as a ratio (%) of the power-on time per unit time. The greater the ratio of the power-on time, the greater the output of the first heater 313.

[0130] Although not shown, when a plurality of first heaters 313 are provided in one area, the ratio of the power-on time of the plurality of first heaters 313 is controlled to be the same. Also, although not shown, a plurality of first temperature detectors 314 may be provided in one area. The number of areas, the number of first heaters 313, and the number of first temperature detectors 314 may be different.

[0131] The set temperature of the cylinder 310 is prepared for each operation mode of the injection molding machine 10. The operation mode of the injection molding machine 10 includes, for example, a molding mode and a heat-keeping mode. In the molding mode, the molding material is injected from the cylinder 310 to the mold device 800. In the heat-keeping mode, the operation of the screw 330 is stopped at night or on weekends. In the heat-keeping mode, in order to suppress carbonization of the molding material, the temperature of the cylinder 310 is set lower than that in the molding mode.

[0132] The operation mode of the injection molding machine 10 may further include a purge mode. In the purge mode, for example, after the insulation mode and before the molding mode, the molding material is injected from the cylinder 310 to the outside of the mold device 800, thereby replacing the molding material in the cylinder 310. In the purge mode, the temperature of the cylinder 310 is set lower than that in the molding mode.

[0133] The temperature control unit 715 sometimes raises the temperature of the cylinder 310. For example, the temperature of the cylinder 310 is raised when the set temperature for the molding mode is changed to a higher level during the molding mode, when the operation mode of the injection molding machine 10 is switched from the insulation mode or the purge mode to the molding mode, or when the power supply to the heater is cut off due to a power outage or an operating error and then resumed.

[0134] If the temperature of the cylinder 310 is increased greatly, a time lag will occur from the completion of the temperature increase of the cylinder 310 to the completion of the temperature increase of the molding material in the cylinder 310. If the metering motor 340 or the injection motor 350 operates the screw 330 before the molding material in the cylinder 310 is sufficiently heated, an excessive load will be applied to the screw 330, possibly damaging the screw 330. In addition, molding defects may occur.

[0135] Therefore, the cold start prevention unit 716 performs control to restrict the movement of the screw 330 until the molding material in the cylinder 310 is sufficiently heated. The control to restrict the movement of the screw 330 is called cold start prevention. And the time for performing cold start prevention is called cold start prevention time.

[0136] The initial value t0 of the cold start prevention time t is set according to the structure of the injection device 300 and the type of molding material, and is pre-stored in the storage medium 702. The initial value t0 is not particularly limited, and is, for example, 15 minutes. The initial value t0 may be input by the user, or may be automatically set by the control device 700 by acquiring information on the type of molding material.

[0137] The starting point of the cold start prevention time t is not limited to when the temperature rise of the cylinder 310 is completed, that is, when the actual temperature of the cylinder 310 reaches the set temperature. The starting point of the cold start prevention time t can be set arbitrarily. For example, the starting point of the cold start prevention time t can also be when the actual temperature of the cylinder 310 reaches a temperature that is shifted from the set temperature to the low temperature side by a specified amount.

[0138] However, if the temperature rise of the cylinder 310 is small, the molding material in the cylinder 310 is sufficiently heated. In this case, if the initial value t0 is still used as the cold start prevention time, time will be wasted until the molded product is restarted.

[0139] The details will be described later. When the first condition is satisfied, the cold start prevention unit 716 uses the initial value t0 as the cold start prevention time t, and controls the movement of the screw 330 during the initial value t0. However, in order to determine whether a value shorter than the initial value t0 should be used as the cold start prevention time t, the cold start prevention unit 716 determines whether a second condition different from the first condition is satisfied even when the first condition is satisfied. By considering not only the first condition but also the second condition, the cold start prevention time t can be simply and appropriately adjusted.

[0140] Even when the first condition is satisfied, when the second condition is satisfied, the cold start prevention unit 716 will notify that a value shorter than the initial value t0 is used as the cold start prevention time, or a value shorter than the initial value t0 should be used as the cold start prevention time. In the case of notification, it includes displaying on the screen or outputting by sound. After the cold start prevention unit 716 makes the notification, if it detects that a prescribed operation is performed by the user, a value shorter than the initial value t0 is used as the cold start prevention time. In addition, when a value shorter than the initial value t0 is used as the cold start prevention time t, it includes setting the cold start prevention time t to zero, that is, not implementing the cold start prevention.

[0141] Next, refer to Figure 5 An example of the processing of the cold start prevention unit 716 is described. For example, during the startup of the injection molding machine 10, the cold start prevention unit 716 is repeatedly performed at a predetermined time. Figure 5 First, the cold start prevention unit 716 determines whether the set temperature Tref of the cylinder 310 is changed (step S101). The determination target area is preferably the frontmost area of ​​the cylinder 310 (the area closest to the nozzle 320).

[0142] The molding material is injected from the inside of the cylinder 310 through the nozzle 320 into the mold device 800. If the metering motor 340 or the injection motor 350 operates the screw 330 when the molding material is not fully melted in the frontmost area of ​​the cylinder 310, an excessive load will be applied to the screw 330, which may damage the screw 330. In addition, molding failure may occur.

[0143] In the process of the cold start prevention unit 716, the set temperature Tref of the cylinder 310 is preferably the set temperature Tref of the frontmost area of ​​the cylinder 310. In addition, in the process of the cold start prevention unit 716, the actual temperature Tdet of the cylinder 310 is preferably the actual temperature Tdet of the frontmost area of ​​the cylinder 310.

[0144] When the set temperature Tref of the cylinder 310 is changed (step S101, "Yes"), the cold start prevention unit 716 determines whether the cylinder 310 is in a state of temperature increase immediately before the set temperature Tref is changed (step S102). The state of temperature increase of the cylinder 310 is a state in which the actual temperature Tdet of the cylinder 310 reaches the set temperature Tref.

[0145] In steps S101 and S102, the set temperature Tref of the cylinder 310 is changed, which is the first condition. The state of the cylinder 310 is a state where the temperature rise is completed immediately before the first condition is satisfied, which is the second condition. As a case where the first condition is satisfied and the second condition is satisfied, for example, the case where the set temperature Tref for the molding mode is changed during the molding mode can be cited.

[0146] In addition, the set temperature Tref to be changed is not limited to the set temperature Tref for the molding mode, but may be the set temperature Tref for the purge mode. That is, the case where the first condition is satisfied and the second condition is satisfied may also be the case where the set temperature Tref for the purge mode is changed in the purge mode. In addition, in the keep warm mode, since the operation of the screw 330 is stopped, it is excluded from the object of cold start prevention.

[0147] When the first condition is satisfied and the second condition is not satisfied in steps S101 and S102 (step S102, "No"), the temperature rise of the cylinder 310 has not been completed since before the first condition was satisfied. Therefore, the molding material in the cylinder 310 is not fully heated. Therefore, the cold start prevention unit 716 sets the cold start prevention time t to the initial value t0 (step S103), and then performs the processing after step S109. The processing after step S109 will be described later.

[0148] On the other hand, when the first condition is satisfied and the second condition is satisfied in steps S101 and S102 (step S102, "Yes"), if the difference ΔT (ΔT = Tref - Tdet) between the set temperature Tref and the actual temperature Tdet of the cylinder 310 at the time when the first condition is satisfied is small, the molding material in the cylinder 310 has been sufficiently heated. Therefore, the cold start prevention unit 716 performs the processing after step S107. The processing after step S107 will be described later.

[0149] When the set temperature Tref of the cylinder 310 is not changed (step S101, "No"), the cold start prevention unit 716 determines whether the cylinder 310 is in a state of starting to heat up (step S104). As the state of starting to heat up the cylinder 310, for example, the state in which the operation mode of the injection molding machine 10 is switched from the warm-keeping mode or the purge mode to the molding mode, and the state in which the power supply is restarted after being cut off due to a power outage or an operation error can be cited.

[0150] As the operation mode of the injection molding machine 10, a molding mode and a heat preservation mode are prepared. In the molding mode, the set temperature Tref for the molding cycle is used. In the heat preservation mode, the set temperature Tref for heat preservation is used. As the operation mode of the injection molding machine 10, a purge mode can also be prepared. In the purge mode, the set temperature Tref for purge is used.

[0151] When the cylinder 310 is not in the state of starting to heat up (step S104, "No"), the set temperature Tref of the cylinder 310 is not changed nor the operation of the injection molding machine 10 is interrupted, and the molding material in the cylinder 310 is sufficiently heated. Therefore, at this time, the cold start prevention unit 716 does not perform step S109 and ends this process.

[0152] When the cylinder 310 is in a state of starting to heat up (step S104, "Yes"), the cold start prevention unit 716 determines whether the cylinder 310 is in a state of completing heating from the start of heating up of the cylinder 310 to a set time (for example, 15 minutes ago) (step S105). Figure 5 In the example, the setting time is the same as the initial value t0, which is 15 minutes, but it can be set arbitrarily.

[0153] In steps S104 and S105, the cylinder 310 is in a state where the temperature rise has started, which is the first condition. The cylinder 310 is in a state where the temperature rise has been completed before the set time from the moment when the first condition is satisfied, which is the second condition. As the case where the first condition is satisfied and the second condition is satisfied, for example, the case where the power outage time is short and the operation is immediately resumed, the case where the operation is immediately resumed due to an operational error by the user, etc. can be cited.

[0154] When the first condition is satisfied and the second condition is not satisfied in steps S104 and S105 (step S105, "No"), the temperature rise of the cylinder 310 has not been completed since before the first condition was satisfied. Therefore, the molding material in the cylinder 310 is not fully heated. Therefore, the cold start prevention unit 716 sets the cold start prevention time t to the initial value t0 (step S106), and then performs the processing after step S109. The processing after step S109 will be described later.

[0155] On the other hand, when the first condition is satisfied and the second condition is satisfied in steps S104 and S105 (step S105, "Yes"), if the difference ΔT (ΔT = Tref - Tdet) between the set temperature Tref and the actual temperature Tdet of the cylinder 310 at the time when the first condition is satisfied is small, the molding material in the cylinder 310 has been sufficiently heated. Therefore, the cold start prevention unit 716 performs the processing after step S107. The processing after step S107 will be described later.

[0156] In step S107, the cold start prevention unit 716 obtains the set temperature Tref and the actual temperature Tdet of the cylinder 310 at the time when the first condition is satisfied. The set temperature Tref and the actual temperature Tdet are associated with the time and stored in the storage medium 702, and the stored data is read and used.

[0157] Next, the cold start prevention unit 716 determines whether to use a value shorter than the initial value t0 as the cold start prevention time t based on the set temperature Tref and the actual temperature Tdet of the cylinder 310 at the time when the first condition is satisfied. The cold start prevention unit 716 sets a value shorter than the initial value t0 as the cold start prevention time t based on ΔT (ΔT=Tref-Tdet) at the time when the first condition is satisfied (step S108).

[0158] The smaller ΔT is when the first condition is satisfied, the smaller the insufficient heating amount of the molding material in the cylinder 310 is. Therefore, the smaller ΔT is when the first condition is satisfied, the shorter the cold start prevention time t can be set. The cold start prevention time t can be set in stages according to ΔT. In addition, the cold start prevention time t can also be set to zero. In addition, when ΔT is too large when the first condition is satisfied, the molding material in the cylinder 310 is not sufficiently heated, so the cold start prevention time t can be set to the initial value t0.

[0159] In the present embodiment, the cold start prevention unit 716 sets a value shorter than the initial value t0 as the cold start prevention time t according to ΔT at the time when the first condition is satisfied, but the cold start prevention time t may be set to a value shorter than the initial value t0 according to a parameter other than ΔT. For example, the ratio of Tref to Tdet may be used instead of ΔT.

[0160] Alternatively, when the set temperature Tref of the cylinder 310 is changed or the cylinder 310 is in a state of starting to heat up, which is the first condition, the second condition is that the cylinder 310 is heated up before a set time (e.g., 15 minutes) has passed since the first condition was established. When the second condition is established, it can be considered that the molding material in the cylinder 310 has been sufficiently heated. The cold start prevention unit 716 can also determine whether a value shorter than the initial value t0 should be used as the cold start prevention time based on the time from the time when the first condition is established to the time when the cylinder 310 is heated up.

[0161] In step S109 , the cold start prevention unit 716 performs the cold start prevention during the preset cold start prevention time t. Then, the cold start prevention unit 716 ends the current processing.

[0162] In addition, in the present embodiment, the actual temperature of the cylinder 310 is used as the starting point of the cold start prevention time t, but it is also possible to consider using the actual temperature of the mold device 800. The mold device 800 is sometimes equipped with a hot runner not shown. The hot runner is equipped with a heater for heating the flow path of the molding material and a temperature detector for detecting the actual temperature of the flow path of the molding material. The temperature control unit 715 controls the heater so that the actual temperature of the flow path of the molding material becomes the set temperature.

[0163] The temperature control unit 715 sometimes heats up the mold device 800 before restarting the molding cycle. There is a time lag from when the temperature detector of the mold device 800 detects that the temperature rise of the mold device 800 is completed to when the temperature rise of the entire flow path of the molding material is completed. If the metering motor 340 or the injection motor 350 moves the screw 330 when the mold device 800 is not fully heated, the mold device 800 may be damaged or the molding may be defective. Therefore, the cold start prevention unit 716 can control the movement of the screw 330 until the mold device 800 is fully heated.

[0164] The above describes the embodiments of the control device of the injection molding machine, the injection molding machine, and the control method of the injection molding machine involved in the present invention, but the present invention is not limited to the above embodiments, etc. Various changes, corrections, replacements, additions, deletions, and combinations can be made within the scope of 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, the injection molding machine comprising an injection unit for injecting a molding material from a cylinder into a mold device and a drive source for actuating the injection unit, wherein: The control device includes a cold start prevention unit, and when a first condition is satisfied, the cold start prevention unit performs control to limit the operation of the injection component during a preset cold start prevention time. The cold start prevention unit determines whether a second condition different from the first condition is satisfied in order to determine whether a value shorter than an initial value should be used as the cold start prevention time even when the first condition is satisfied.

2. The control device for an injection molding machine according to claim 1, wherein: Even when the first condition is satisfied, when the second condition is satisfied, the cold start prevention unit notifies that a value shorter than the initial value is used as the cold start prevention time, or that a value shorter than the initial value should be used as the cold start prevention time.

3. The control device for an injection molding machine according to claim 1 or 2, wherein: The first condition includes that the set temperature of the cylinder or the mold device is changed, The second condition includes: the cylinder or the mold device is in a state where temperature rise is completed immediately before the first condition is satisfied; or the cylinder or the mold device is in a state where temperature rise is completed before a set time has passed since the first condition is satisfied.

4. The control device for an injection molding machine according to claim 1 or 2, wherein: The first condition includes that the cylinder or the mold device is in a state where the temperature is starting to rise. The second condition includes: the cylinder or the mold device is in a state of heating up from the time when the first condition is satisfied to a set time; or the cylinder or the mold device is heated up before a set time has passed since the first condition is satisfied.

5. The control device for an injection molding machine according to claim 1 or 2, wherein: The cold start prevention unit determines whether a value shorter than an initial value should be used as the cold start prevention time based on a set temperature and an actual temperature of the cylinder or the mold device at a time when the first condition is satisfied.

6. The control device for an injection molding machine according to claim 1 or 2, wherein: The cold start prevention unit determines whether a value shorter than an initial value should be used as the cold start prevention time based on the time from when the first condition is satisfied to when the temperature rise of the cylinder or the mold device is completed.

7. An injection molding machine, in, A control device according to claim 1 or 2, the injection component and the drive source.

8. A control method for an injection molding machine, the injection molding machine comprising a driving source for actuating an injection member for injecting a molding material from a cylinder into a mold device, wherein: When the first condition is satisfied, control is performed to limit the movement of the injection component during a preset cold start prevention time. In order to determine whether a value shorter than the initial value should be used as the cold start prevention time, even when the first condition is satisfied, it is determined whether a second condition different from the first condition is satisfied.

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