Injection molding machine control unit

Abstract

To reduce the occurrence of molding defects.SOLUTION: The control unit of an injection molding machine according to the embodiment is a control unit that controls an injection molding machine equipped with a mold device having a fixed mold and a movable mold, a mold clamping device that opens and closes the fixed mold and the movable mold, and an injection machine that injects molding material into the mold device, and the control unit has an acquisition unit and an adjustment unit. When the molding material is injected into the mold device, the acquisition unit acquires an allowable tolerance for a gap between the stationary mold and the movable mold to suppress the discharge of molding material from the mold apparatus, and acquires a gap amount indicating the size of the gap provided between the stationary mold and the movable mold for ejection of gas, and when the molding material is injected into the mold apparatus closed by the mold clamping device, the adjustment unit adjusts the mold clamping force of the mold clamping device so that the value based on the amount of opening between the fixed mold and the movable mold caused by the injection of the material, the amount of gap, and the condition by the allowable amount is satisfied.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] Conventionally, an injection molding machine includes a mold device including a fixed mold and a movable mold, a mold clamping device for clamping the mold device, and an injection device for filling a molding material into the mold device. When the injection device fills the molding material into the mold device, the mold clamping device needs to close the mold device with an appropriate clamping force.

[0003] The clamping force setting method of Patent Document 1 generates a clamping force with two or more different set clamping forces to perform injection, and detects the clamping force during the injection. Then, a relational expression between the maximum value of the detected clamping force and the set clamping force is obtained, and a clamping force is obtained from the relational expression such that the maximum value of the detected clamping force and the set clamping force are equal, and the obtained clamping force is set.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As shown in Patent Document 1, conventionally, a method for setting a clamping force has been proposed. However, it is difficult to derive an appropriate clamping force. For example, when the clamping force is small, the fixed mold and the movable mold are opened by the pressure of the molding material, the molding material leaks, and burrs are generated. That is, it is necessary to adjust the clamping force in consideration of the opening amount of the mold device 800.

[0006] One aspect of the present invention provides a technique for reducing the occurrence of molding defects.

Means for Solving the Problems

[0007] The control device for an injection molding machine according to one aspect of the present invention is a control device for controlling an injection molding machine including a mold device having a fixed mold and a movable mold, a mold clamping device for opening and closing the fixed mold and the movable mold, and an injection machine for injecting a molding material into the mold device. When the molding material is injected into the mold device, in order to suppress the discharge of the molding material from the mold device, an allowable amount allowed as the size of the gap between the fixed mold and the movable mold is acquired, and a gap amount indicating the size of a gap provided for discharging gas between the fixed mold and the movable mold is acquired. An acquisition unit; and an adjustment unit that adjusts the mold clamping force of the mold clamping device so that a value based on the amount of opening between the fixed mold and the movable mold caused by the injection of the molding material and the gap amount satisfies the condition based on the allowable amount when the molding material is injected into the mold device closed by the mold clamping device.

Effect of the Invention

[0008] According to one aspect of the present invention, by adjusting the mold clamping force of the mold clamping device, the occurrence of molding defects is reduced.

Brief Description of the Drawings

[0009]

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DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the embodiments described below are examples and do not limit the invention, and not all features and combinations thereof described in the embodiments are necessarily essential to the invention. In each drawing, the same or corresponding components are denoted by the same or corresponding reference numerals, and the description may be omitted.

[0011] FIG. 1 is a view showing the state of the injection molding machine according to the first embodiment at the time of mold opening completion. FIG. 2 is a view showing the state of the injection molding machine according to the first embodiment at the time of mold clamping. 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 mold clamping device 100 is a horizontal mold, 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 in the Y-axis direction is called the operation side, and the positive side in the Y-axis direction is called the non-operation side.

[0012] As shown in FIGS. 1 to 2, the injection molding machine 10 includes a mold clamping device 100 that opens and closes the mold device 800, an ejector device 200 that ejects the molded product formed by the mold device 800, an injection device 300 that injects the molding material into the mold device 800, a moving device 400 that moves the injection device 300 forward and backward with respect to the mold device 800, a control device 700 that controls each component of the injection molding machine 10, and a frame 900 that supports each component of the injection molding machine 10. The frame 900 includes a mold clamping device frame 910 that supports the mold clamping device 100 and an injection device frame 920 that supports the injection device 300. The mold clamping device frame 910 and the injection device frame 920 are each installed on the floor 2 via a leveling adjuster 930. The control device 700 is disposed in the internal space of the injection device frame 920. Hereinafter, each component of the injection molding machine 10 will be described.

[0013] (Mold clamping device) In 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 defined 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 defined as the rear for explanation.

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

[0015] The fixed platen 110 is fixed to the clamping device frame 910. The fixed mold 810 is attached to the opposing surface of the fixed platen 110 with respect to the movable platen 120.

[0016] The movable platen 120 is arranged movably in the mold opening / closing direction with respect to the clamping device frame 910. A guide 101 for guiding the movable platen 120 is laid on the clamping device frame 910. The movable mold 820 is attached to the opposing surface of the movable platen 120 with respect to the fixed platen 110.

[0017] The moving mechanism 102 performs mold closing, pressure boosting, mold clamping, pressure release, and mold opening of the mold device 800 by advancing and retracting the movable platen 120 with respect to the fixed platen 110. The moving mechanism 102 has a toggle support 130 arranged at an interval from the fixed platen 110, a tie bar 140 connecting the fixed platen 110 and the toggle support 130, a toggle mechanism 150 that moves the movable platen 120 in the mold opening / closing direction with respect to the toggle support 130, a clamping motor 160 that operates the toggle mechanism 150, a motion conversion mechanism 170 that converts the rotational motion of the clamping motor 160 into a linear motion, and a mold thickness adjustment mechanism 180 that adjusts the interval between the fixed platen 110 and the toggle support 130.

[0018] The toggle support 130 is disposed at an interval from the fixed platen 110 and is movably placed in the mold opening / closing direction on the mold clamping device frame 910. Note that the toggle support 130 may be movably arranged along a guide laid on the mold clamping device frame 910. The guide of the toggle support 130 may be common with the guide 101 of the movable platen 120.

[0019] In this embodiment, the fixed platen 110 is fixed to the mold clamping device frame 910, and the toggle support 130 is movably arranged in the mold opening / closing direction with respect to the mold clamping device frame 910. However, the toggle support 130 may be fixed to the mold clamping device frame 910, and the fixed platen 110 may be movably arranged in the mold opening / closing direction with respect to the mold clamping device frame 910.

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

[0021] In this embodiment, the tie bar strain detector 141 is used as the clamping force detector for detecting the clamping force. However, the present invention is not limited to this. The clamping force detector is not limited to the strain gauge type, and may be a piezoelectric type, a capacitive type, a hydraulic type, an electromagnetic type, or the like, and its mounting position is not limited to the tie bar 140.

[0022] The toggle mechanism 150 is disposed between the movable platen 120 and the toggle support 130, and moves the movable platen 120 in the mold opening and closing direction with respect to the toggle support 130. The toggle mechanism 150 has a crosshead 151 that moves in the mold opening and closing direction, and a pair of link groups that flex by the movement of the crosshead 151. Each of the pair of link groups has a first link 152 and a second link 153 that are flexibly connected by a pin or the like. The first link 152 is swingably attached to the movable platen 120 by a pin or the like. The second link 153 is swingably attached to the toggle support 130 by a pin or the like. The second link 153 is attached to the crosshead 151 via a third link 154. When the crosshead 151 is advanced and retracted with respect to the toggle support 130, the first link 152 and the second link 153 flex, and the movable platen 120 advances and retracts with respect to the toggle support 130.

[0023] Note that the configuration of the toggle mechanism 150 is not limited to the configuration shown in FIGS. 1 and 2. For example, in FIGS. 1 and 2, the number of nodes of each link group is five, but it may be four, and one end of the third link 154 may be coupled to the node between the first link 152 and the second link 153.

[0024] The mold clamping motor 160 is attached to the toggle support 130 and operates the toggle mechanism 150. The mold clamping motor 160 advances and retracts the crosshead 151 with respect to the toggle support 130, thereby flexing the first link 152 and the second link 153, and advancing and retracting the movable platen 120 with respect to the toggle support 130. The mold clamping motor 160 is directly connected to the motion conversion mechanism 170, but may be connected to the motion conversion mechanism 170 via a belt, a pulley, or the like.

[0025] The motion conversion mechanism 170 converts the rotational motion of the mold clamping motor 160 into the linear motion of the crosshead 151. The motion conversion mechanism 170 includes a screw shaft and a screw nut that engages with the screw shaft. A ball or a roller may be interposed between the screw shaft and the screw nut.

[0026] The mold clamping device 100 performs operations such as a mold closing process, a pressure boosting process, a mold clamping process, a pressure releasing process, and a mold opening process under the control of the control device 700.

[0027] In the mold closing process, the mold clamping motor 160 is driven to advance the crosshead 151 to the mold closing completion position at a set moving speed, thereby advancing the movable platen 120 and bringing the movable mold 820 into contact with the fixed mold 810. The position and moving speed of the crosshead 151 are detected using, for example, the 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.

[0028] Note that 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 general ones 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 mold clamping motor encoder 161, and general ones can be used.

[0029] In the pressure boosting process, the mold clamping motor 160 is further driven to advance the crosshead 151 from the mold closing completion position to the mold clamping position to generate a mold clamping force.

[0030] 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 boosting process is maintained. In the mold clamping process, a cavity space 801 (see Figure 2) is formed between the movable mold 820 and the fixed mold 810, and the injection device 300 fills the cavity space 801 with a liquid molding material. The filled molding material is solidified to obtain a molded product.

[0031] The number of cavity spaces 801 may be one or more than one. In the latter case, a plurality of molded articles can be obtained simultaneously. An insert material 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 article in which the insert material and the molding material are integrated can be obtained.

[0032] In the mold release process, the mold clamping motor 160 is driven to retract the crosshead 151 from the mold clamping position to the mold opening start position, thereby retracting the movable platen 120 and reducing the mold clamping force. The mold opening start position and the mold closing completion position may be the same position.

[0033] In the mold opening process, the mold clamping motor 160 is driven to retract the crosshead 151 from the mold opening start position to the mold opening completion position at a set moving speed, thereby retracting the movable platen 120 and separating the movable mold 820 from the fixed mold 810. Then, the ejector device 200 protrudes the molded article from the movable mold 820.

[0034] The setting conditions in the mold closing process, the pressure boosting process, and the mold clamping process are set together as a series of setting conditions. For example, the moving speed and position of the crosshead 151 (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 in the mold closing process and the pressure boosting 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 this order from the rear to the front and represent the start point and the end point of the section where the moving speed is set. The moving speed is set for each section. The number of moving speed switching positions may be one or more than one. The moving speed switching position may not be set. Either the mold clamping position or the mold clamping force may be set alone.

[0035] The setting conditions in the pressure release process and the mold opening process are also set in the same way. For example, the moving speed and position of the crosshead 151 (mold opening start position, moving speed switching position, and mold opening completion position) in the pressure release process and the 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 this order from the front to the rear, and represent the start and end points of the section where the moving speed is set. The moving speed is set for each section. The moving speed switching position may be one or more. The moving speed switching position may not be set. The mold opening start position and the mold closing completion position may be the same position. Also, the mold opening completion position and the mold closing start position may be the same position.

[0036] Note that instead of the moving speed and position of the crosshead 151, etc., the moving speed and position of the movable platen 120, etc. may be set. Also, instead of the position of the crosshead (for example, the mold clamping position) and the position of the movable platen, the mold clamping force may be set.

[0037] By the way, the toggle mechanism 150 amplifies the driving force of the mold clamping motor 160 and transmits it to the movable platen 120. The amplification 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 the "link angle θ"). The link angle θ is obtained from the position of the crosshead 151. When the link angle θ is 180°, the toggle ratio becomes the maximum.

[0038] When the thickness of the mold device 800 changes due to the replacement of the mold device 800 or the temperature change of the mold device 800, etc., mold thickness adjustment is performed so that a predetermined mold clamping force can be obtained during mold clamping. In the mold thickness adjustment, for example, the interval L between the fixed platen 110 and the toggle support 130 is adjusted so that the link angle θ of the toggle mechanism 150 becomes a predetermined angle at the time of mold touch when the movable mold 820 touches the fixed mold 810.

[0039] The mold clamping device 100 has a mold thickness adjustment mechanism 180. The mold thickness adjustment mechanism 180 adjusts the mold thickness by adjusting the distance L between the fixed platen 110 and the toggle support 130. Note that the timing of the mold thickness adjustment is performed, for example, between the end of the molding cycle and the start of the next molding cycle. The mold thickness adjustment mechanism 180 includes, for example, a screw shaft 181 formed at the rear end of the tie bar 140, a nut 182 rotatably and non-axially held by the toggle support 130, and a mold thickness adjustment motor 183 that rotates the nut 182 screwed onto the screw shaft 181.

[0040] The screw shaft 181 and the nut 182 are provided for each tie bar 140. The rotational driving force of the mold thickness adjustment motor 183 may be transmitted to a plurality of nuts 182 via a rotational driving force transmission unit 185. The plurality of nuts 182 can be rotated synchronously. Note that it is also possible to rotate the plurality of nuts 182 individually by changing the transmission path of the rotational driving force transmission unit 185.

[0041] The rotational driving force transmission unit 185 is composed of, for example, gears. In this case, a driven gear is formed on the outer periphery of each nut 182, a driving gear is attached to 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 support 130. Note that the rotational driving force transmission unit 185 may be composed of a belt, a pulley, or the like instead of gears.

[0042] The operation of the mold thickness adjustment mechanism 180 is controlled by a control device 700. The control device 700 drives the mold thickness adjustment motor 183 to rotate the nut 182. As a result, the position of the toggle support 130 relative to the tie bar 140 is adjusted, and the distance L between the fixed platen 110 and the toggle support 130 is adjusted. Note that a plurality of mold thickness adjustment mechanisms may be used in combination.

[0043] The interval L is detected using the mold thickness adjustment motor encoder 184. The mold thickness adjustment motor encoder 184 detects the amount and direction of rotation of the mold thickness adjustment motor 183, and sends a signal indicating the detection result to the control device 700. The detection result of the mold thickness adjustment motor encoder 184 is used for monitoring and controlling the position of the toggle support 130 and the interval L. Note that the toggle support position detector for detecting the position of the toggle support 130 and the interval detector for detecting the interval L are not limited to the mold thickness adjustment motor encoder 184, and general ones can be used.

[0044] The mold clamping device 100 may have a mold temperature controller for adjusting the temperature of the mold device 800. The mold device 800 has a flow path for a temperature control medium inside. The mold temperature controller adjusts the temperature of the mold device 800 by adjusting the temperature of the temperature control medium supplied to the flow path of the mold device 800.

[0045] Note that the mold clamping device 100 of this embodiment is a horizontal type in which the mold opening / closing direction is the horizontal direction, but it may also be a vertical type in which the mold opening / closing direction is the vertical direction.

[0046] Note that the mold clamping device 100 of this embodiment has a mold clamping motor 160 as a drive source, but it may have a hydraulic cylinder instead of the mold clamping motor 160. Further, the mold clamping device 100 may have a linear motor for mold opening / closing and an electromagnet for mold clamping.

[0047] (Ejector device) 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 defined 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 defined as the rear for explanation.

[0048] The ejector device 200 is attached to the movable platen 120 and moves forward and backward together with the movable platen 120. The ejector device 200 has an ejector rod 210 for protruding the molded product from the mold device 800 and a drive mechanism 220 for moving the ejector rod 210 in the moving direction (X-axis direction) of the movable platen 120.

[0049] The ejector rod 210 is disposed in a through hole of the movable platen 120 so as to be movable forward and backward. The front end of the ejector rod 210 contacts the ejector plate 826 of the movable mold 820. The front end of the ejector rod 210 may or may not be connected to the ejector plate 826.

[0050] The drive mechanism 220 includes, for example, an ejector motor and a motion conversion mechanism that converts the rotational motion of the ejector motor into the linear motion of the ejector rod 210. The motion conversion mechanism includes a screw shaft and a screw nut that engages with the screw shaft. A ball or a roller may be interposed between the screw shaft and the screw nut.

[0051] Under the control of the control device 700, the ejector device 200 performs a protruding process. In the protruding process, the ejector rod 210 is advanced from the standby position to the protruding position at a set moving speed, so that the ejector plate 826 is advanced to eject the molded product. Then, the ejector motor is driven to retract the ejector rod 210 at the set moving speed, and the ejector plate 826 is retracted to the original standby position.

[0052] The position and moving speed of the ejector rod 210 are detected using, for example, an ejector motor encoder. The ejector motor encoder detects the rotation of the ejector motor and sends a signal indicating the detection result to the control device 700. Note that the ejector rod position detector that detects the position of the ejector rod 210 and the ejector rod moving speed detector that detects the moving speed of the ejector rod 210 are not limited to the ejector motor encoder, and general ones can be used.

[0053] (Injection device) In the description of the injection device 300, unlike the description of the mold clamping device 100 and the ejector device 200, the moving direction of the screw 330 during filling (for example, the negative X-axis direction) is described as the front, and the moving direction of the screw 330 during metering (for example, the positive X-axis direction) is described as the rear.

[0054] The injection device 300 is installed on the slide base 301, and the slide base 301 is disposed to be movable forward and backward with respect to the injection device frame 920. The injection device 300 is disposed to be movable forward and backward with respect to the mold device 800. The injection device 300 touches the mold device 800 and fills the cavity space 801 in the mold device 800 with the molding material measured in the cylinder 310. The injection device 300 includes, for example, a cylinder 310 that heats the molding material, a nozzle 320 provided at the front end of the cylinder 310, a screw 330 disposed to be movable forward and backward and rotatable within the cylinder 310, a metering motor 340 that rotates the screw 330, an injection motor 350 that moves the screw 330 forward and backward, and a load detector 360 that detects the load transmitted between the injection motor 350 and the screw 330.

[0055] The cylinder 310 heats the molding material supplied therein from the supply port 311. The molding material includes, for example, resin or the like. The molding material is formed, for example, in the form of pellets and is 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 heater 313 such as a band heater and a temperature detector 314 are provided on the outer periphery of the cylinder 310 in front of the cooler 312.

[0056] The cylinder 310 is divided into a plurality of zones in the axial direction (for example, the X-axis direction) of the cylinder 310. A heater 313 and a temperature detector 314 are provided in each of the plurality of zones. A set temperature is set for each of the plurality of zones, and the control device 700 controls the heater 313 so that the detected temperature of the temperature detector 314 becomes the set temperature.

[0057] The nozzle 320 is provided at the front end of the cylinder 310 and is pressed against the mold device 800. A heater 313 and a temperature detector 314 are provided on the outer periphery of the nozzle 320. The control device 700 controls the heater 313 so that the detected temperature of the nozzle 320 becomes the set temperature.

[0058] The screw 330 is rotatably and axially displaceably disposed within the cylinder 310. When the screw 330 is rotated, the molding material is fed forward along the spiral groove of the screw 330. While being fed forward, the molding material is gradually melted by the heat from the cylinder 310. As the liquid molding material is fed forward to the front of the screw 330 and accumulates at the front portion of the cylinder 310, the screw 330 is retracted. Thereafter, when the screw 330 is advanced, the liquid molding material accumulated in front of the screw 330 is injected from the nozzle 320 and fills the mold device 800.

[0059] A backflow prevention ring 331 is axially displaceably attached to the front portion of the screw 330 as a backflow prevention valve that prevents backflow of the molding material from the front to the rear of the screw 330 when the screw 330 is pushed forward.

[0060] When the screw 330 is advanced, the backflow prevention ring 331 is pushed rearward by the pressure of the molding material in front of the screw 330 and relatively retracts with respect to the screw 330 to a closed position (see FIG. 2) where the flow path of the molding material is blocked. Thereby, backflow of the molding material accumulated in front of the screw 330 to the rear is prevented.

[0061] On the other hand, when the screw 330 is rotated, the backflow prevention ring 331 is pushed forward by the pressure of the molding material fed forward along the spiral groove of the screw 330 and relatively advances with respect to the screw 330 to an open position (see FIG. 1) where the flow path of the molding material is opened. Thereby, the molding material is fed to the front of the screw 330.

[0062] The backflow prevention ring 331 may be either a co-rotating type that rotates with the screw 330 or a non-co-rotating type that does not rotate with the screw 330.

[0063] Note that the injection device 300 may have a drive source that axially displaces the backflow prevention ring 331 with respect to the screw 330 between the open position and the closed position.

[0064] The metering motor 340 rotates the screw 330. The drive source for rotating the screw 330 is not limited to the metering motor 340 and may be, for example, a hydraulic pump or the like.

[0065] The injection motor 350 moves the screw 330 forward and backward. Between the injection motor 350 and the screw 330, a motion conversion mechanism or the like for converting the rotational motion of the injection motor 350 into the linear motion of the screw 330 is provided. The motion conversion mechanism has, for example, a screw shaft and a screw nut screwed onto the screw shaft. Between the screw shaft and the screw nut, balls, rollers or the like may be provided. The drive source for moving the screw 330 forward and backward is not limited to the injection motor 350 and may be, for example, a hydraulic cylinder or the like.

[0066] 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 in the load transmission path between the injection motor 350 and the screw 330 and detects the load acting on the load detector 360.

[0067] 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 controlling and monitoring the pressure received by the screw 330 from the molding material, the back pressure on the screw 330, the pressure acting on the molding material from the screw 330, and the like.

[0068] Note that the pressure detector for detecting the pressure of the molding material is not limited to the load detector 360, and a general one can be used. For example, a nozzle pressure sensor or an in-mold pressure sensor may be used. The nozzle pressure sensor is installed in the nozzle 320.

[0069] The injection device 300 performs a metering process, a filling process, a pressure holding process, etc. under the control of the control device 700. The filling process and the pressure holding process may be collectively referred to as an injection process.

[0070] In the metering process, the metering motor 340 is driven to rotate the screw 330 at a set rotational speed, and the molding material is fed forward along the spiral groove of the screw 330. Along with this, the molding material is gradually melted. As the liquid molding material is fed forward of the screw 330 and accumulates at the front part of the cylinder 310, the screw 330 is retracted. The rotational speed of the screw 330 is detected using, for example, the metering motor encoder 341. The metering motor encoder 341 detects the rotation of the metering motor 340 and sends a signal indicating the detection result to the control device 700. Note that the screw rotation speed detector for detecting the rotational speed of the screw 330 is not limited to the metering motor encoder 341, and a general one can be used.

[0071] In the metering process, in order to limit a sudden retraction of the screw 330, the injection motor 350 may be driven to apply a set back pressure to the screw 330. The back pressure on the screw 330 is detected using, for example, the load detector 360. When the screw 330 retracts to the metering completion position and a predetermined amount of molding material accumulates in front of the screw 330, the metering process is completed.

[0072] The position and rotational 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 rotational speed switching position, and the metering completion position are set. These positions are arranged in this order from the front to the rear, and represent the start point and end point of the section where the rotational speed is set. The rotational speed is set for each section. The rotational speed switching position may be one or a plurality. The rotational speed switching position may not be set. Also, the back pressure is set for each section.

[0073] In the filling process, the injection motor 350 is driven to move the screw 330 forward at a set moving speed, and the liquid molding material accumulated in front of the screw 330 is filled into the cavity space 801 in the mold device 800. The position and moving speed of the screw 330 are detected, for example, using the injection motor encoder 351. The injection motor encoder 351 detects the rotation of the injection motor 350 and sends a signal indicating the detection result to the control device 700. When the position of the screw 330 reaches the set position, the switching from the filling process to the holding pressure process (so-called V / P switching) is performed. The position where the V / P switching is performed is also called the V / P switching position. The set moving speed of the screw 330 may be changed according to the position and time of the screw 330, etc.

[0074] The position and moving speed of the screw 330 in the filling process are set together as a series of setting conditions. For example, the filling start position (also called the "injection start position"), the moving speed switching position, and the V / P switching position are set. These positions are arranged in this order from the rear to the front and represent the start and end points of the section where the moving speed is set. The moving speed is set for each section. The moving speed switching position may be one or more. The moving speed switching position may not be set.

[0075] For each section where the moving speed of the screw 330 is set, the upper limit value of the pressure 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 is advanced at the set moving speed. On the other hand, when the pressure of the screw 330 exceeds the set pressure, for the purpose of mold protection, the screw 330 is advanced at a moving speed slower than the set moving speed so that the pressure of the screw 330 becomes below the set pressure.

[0076] In addition, after the position of the screw 330 reaches the V / P switching position in the filling process, the screw 330 may be temporarily stopped at the V / P switching position, and then the V / P switching may be performed. Immediately before the V / P switching, instead of stopping the screw 330, the screw 330 may be advanced or retracted at a very low speed. Also, 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 general ones can be used.

[0077] In the holding pressure process, the injection motor 350 is driven to push the screw 330 forward, maintaining the pressure of the molding material at the front end of the screw 330 (hereinafter, also referred to as "holding pressure") at the set pressure, and pushing the molding material remaining in the cylinder 310 toward the mold device 800. The insufficient molding material due to cooling shrinkage in the mold device 800 can be replenished. The holding pressure is detected using, for example, the load detector 360. The set value of the holding pressure may be changed according to the elapsed time from the start of the holding pressure process and the like. A plurality of holding pressures and holding times for maintaining the holding pressure may be set respectively, and may be set together as a series of setting conditions.

[0078] In the holding pressure process, the molding material in the cavity space 801 in the mold device 800 is gradually cooled, and at the end of the holding pressure process, the entrance of the cavity space 801 is blocked by the solidified molding material. This state is called gate sealing, and the backflow of the molding material from the cavity space 801 is prevented. After the holding pressure process, the cooling process is started. 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 may be performed during the cooling process.

[0079] Note that the injection device 300 of the present embodiment is of the in-line screw type, but it may also be of the pre-plug type or the like. The injection device of the pre-plug 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, a screw is disposed rotatably and non-axially movable, or the screw is disposed rotatably and axially movable. On the other hand, in the injection cylinder, a plunger is disposed axially movable.

[0080] Also, the injection device 300 of the present embodiment is horizontal with the axial direction of the cylinder 310 being the horizontal direction, but it may be vertical with the axial direction of the cylinder 310 being the vertical direction. The mold clamping device combined with the vertical injection device 300 may be vertical or horizontal. Similarly, the mold clamping device combined with the horizontal injection device 300 may be horizontal or vertical.

[0081] (Moving device) In the description of the moving device 400, similar to the description of the injection device 300, the moving direction of the screw 330 during filling (for example, the negative X-axis direction) is defined as the front, and the moving direction of the screw 330 during metering (for example, the positive X-axis direction) is defined as the rear for explanation.

[0082] The moving device 400 moves the injection device 300 forward and backward with respect to the mold device 800. Further, the moving device 400 presses the nozzle 320 against the mold device 800 to generate a nozzle touch pressure. The moving device 400 includes a hydraulic pump 410, a motor 420 as a drive source, a hydraulic cylinder 430 as a hydraulic actuator, and the like.

[0083] The hydraulic pump 410 has a first port 411 and a second port 412. The hydraulic pump 410 is a pump that can rotate in both directions. By switching the rotation direction of the motor 420, hydraulic pressure is generated by sucking the hydraulic fluid (for example, oil) from one of the first port 411 and the second port 412 and discharging it from the other. Note that the hydraulic pump 410 can also suck the hydraulic fluid from the tank and discharge the hydraulic fluid from one of the first port 411 and the second port 412.

[0084] The motor 420 actuates the hydraulic pump 410. The motor 420 drives the hydraulic pump 410 with a rotational direction and a rotational torque according to a control signal from the control device 700. The motor 420 may be an electric motor and may be an electric servo motor.

[0085] 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 inside of the cylinder body 431 into a front chamber 435 as a first chamber and a rear chamber 436 as a second chamber. The piston rod 433 is fixed to the fixed platen 110.

[0086] 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. By supplying the hydraulic fluid discharged from the first port 411 to the front chamber 435 via the first flow path 401, the injection device 300 is pushed forward. The injection device 300 advances and the nozzle 320 is pressed against the fixed mold 810. The front chamber 435 functions as a pressure chamber that generates a nozzle touch pressure of the nozzle 320 by the pressure of the hydraulic fluid supplied from the hydraulic pump 410.

[0087] 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. By supplying the hydraulic fluid discharged from the second port 412 to the rear chamber 436 of the hydraulic cylinder 430 via the second flow path 402, the injection device 300 is pushed backward. The injection device 300 retreats and the nozzle 320 is separated from the fixed mold 810.

[0088] In addition, in this embodiment, the moving device 400 includes the hydraulic cylinder 430, but the present invention is not limited thereto. For example, instead of the hydraulic cylinder 430, an electric motor and a motion conversion mechanism that converts the rotational motion of the electric motor into a linear motion of the injection device 300 may be used.

[0089] (Control device) The control device 700 is configured by, for example, a computer and includes a CPU (Central Processing Unit) 701, a storage medium 702 such as a memory, an input interface 703, an output interface 704, and a communication interface 705 as shown in FIGS. 1 and 2. The control device 700 performs various controls by causing the CPU 701 to execute a program stored in the storage medium 702. Further, the control device 700 receives a signal from the outside through the input interface 703 and transmits a signal to the outside through the output interface 704.

[0090] The control device 700 repeatedly produces molded products by repeatedly performing 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 releasing process, a mold opening process, a pushing out process, and the like. A series of operations for obtaining a molded product, for example, the operations from the start of the metering process to the start of the next metering process, are also called "shots" or "molding cycles". Further, the time required for one shot is also called "molding cycle time" or "cycle time".

[0091] One molding cycle has, for example, 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 releasing process, a mold opening process, and a pushing out process in this order. The order here is the order of the start of each process. 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 releasing process coincides with the start of the mold opening process.

[0092] In addition, for the purpose of shortening the molding cycle time, a plurality of 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 first in the molding cycle. Also, the filling process may be started during the mold closing process. Further, the ejection process may 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 may 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 does not leak from the nozzle 320.

[0093] In addition, one molding cycle may include processes other than the metering process, mold closing process, pressure increasing process, mold clamping process, filling process, pressure holding process, cooling process, pressure releasing process, mold opening process, and ejection process.

[0094] For example, after the completion of the pressure holding process and before the start of the metering process, a pre-metering suck-back process of retracting the screw 330 to a preset metering start position may be performed. This can reduce the pressure of the molding material accumulated in front of the screw 330 before the start of the metering process and prevent the sudden retraction of the screw 330 at the start of the metering process.

[0095] Also, after the completion of the metering process and before the start of the filling process, a post-metering suck-back process of retracting the screw 330 to a preset filling start position (also referred to as the "injection start position") may be performed. This can reduce the pressure of the molding material accumulated in front of the screw 330 before the start of the filling process and prevent the leakage of the molding material from the nozzle 320 before the start of the filling process.

[0096] The control device 700 is connected to an operation device 750 that receives input operations from the user and a display device 760 that displays a screen. The operation device 750 and the display device 760 may be configured by, 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, information such as settings of the injection molding machine 10 and the current state of the injection molding machine 10 may be displayed. The touch panel 770 enables operations to be received in the displayed screen area. Also, in the screen area of the touch panel 770, operation units such as buttons and input fields for receiving input operations by the user may be displayed. The touch panel 770 as the operation device 750 detects input operations on the screen by the user and outputs a signal corresponding to the input operation to the control device 700. Thereby, for example, the user can perform settings (including input of set values) of the injection molding machine 10 by operating the operation units provided on the screen while checking the information displayed on the screen. Also, by the user operating the operation units provided on the screen, the operation of the injection molding machine 10 corresponding to the operation units can be made to occur. Note that the operation of the injection molding machine 10 may be, for example, the operation (including stopping) of the mold clamping device 100, the ejector device 200, the injection device 300, the moving device 400, etc. Also, the operation of the injection molding machine 10 may be, for example, the switching of the screen displayed on the touch panel 770 as the display device 760.

[0097] Note that although the operation device 750 and the display device 760 of the present embodiment have been described as being integrated as the touch panel 770, they may be provided independently. Also, a plurality of operation devices 750 may be provided. The operation device 750 and the display device 760 are arranged on the operation side (Y-axis negative direction) of the mold clamping device 100 (more specifically, the fixed platen 110).

[0098] FIG. 3 is a diagram showing an example of the functional configuration of the control device 700 according to the present embodiment. As shown in FIG. 3, FIG. 3 shows the components of the control device 700 of the injection molding machine 10 as functional blocks. Each functional block shown in FIG. 3 is conceptual and does not necessarily have to be physically configured as shown. All or part of each functional block can be functionally or physically distributed and integrated in any unit. Each processing function performed in each functional block is realized by a program executed by the CPU 701, either in whole or in any part. Alternatively, each functional block may be realized as hardware by wired logic. As shown in FIG. 3, the CPU 701 of the control device 700 includes, for example, a clamping control unit 711, an injection control unit 712, an acquisition unit 713, an adjustment unit 714, an output control unit 715, and a log information processing unit 716. The storage medium 702 of the control device 700 includes a maximum allowable value storage unit 721.

[0099] The clamping control unit 711 controls the clamping drive source of the clamping device 100 and performs the mold closing process, the pressure increasing process, the clamping process, the pressure releasing process, and the mold opening process shown in FIG. 4. The clamping drive source is, for example, the clamping motor 160, but may also be a hydraulic cylinder or the like.

[0100] The injection control unit 712 controls the injection drive source of the injection device 300 and performs the injection process. The injection drive source is, for example, the injection motor 350, but may also be a hydraulic cylinder or the like. The injection process includes a filling process and a holding pressure process. The injection process is performed during the clamping process.

[0101] The filling process is a process of controlling the injection drive source so that the actual value of the moving speed of the injection member provided inside the cylinder 310 becomes the set value. The filling process is a process of moving the injection member forward to fill the liquid molding material accumulated in front of the injection member into the inside of the mold device 800. The injection member is, for example, the screw 330 (see FIGS. 1 and 2), but may also be a plunger.

[0102] The moving speed of the injection member is detected using a speed detector. The speed detector is, for example, the injection motor encoder 351. In the filling process, as the injection member moves forward, the pressure acting on the molding material from the injection member (hereinafter also referred to as "filling pressure") increases. The filling process may include a step of temporarily stopping the injection member or a step of retracting the injection member immediately before the holding pressure process.

[0103] The holding pressure process is a process of controlling the injection drive source so that the actual value of the filling pressure becomes the set value. The holding pressure process is a process of replenishing the insufficient molding material due to cooling shrinkage in the mold device 800 by pushing the injection member forward. The filling pressure is detected using a pressure detector such as the load detector 360. As the pressure detector, a nozzle pressure sensor or an in-mold pressure sensor may be used.

[0104] The injection process is performed during the mold clamping process as described above. The mold clamping control unit 711, for example, converts the set value of the mold clamping force into the set value of the crosshead position and controls the mold clamping motor 160 so that the actual value of the crosshead position becomes the set value. The crosshead position is the relative position of the crosshead 151 (see FIG. 2) with respect to the toggle support 130. The greater the forward movement of the crosshead 151, the greater the mold clamping force.

[0105] Next, with reference to FIG. 5, an example of the molding material M flowing into the mold device 800 will be described. The molding material M is, for example, resin. The molding material M flows into the cavity space 801 inside the mold device 800. The cavity space 801 is formed on the parting surface 830 between the fixed mold 810 and the movable mold 820. The parting surface 830 is generally called a parting line.

[0106] After the molding material M is injected by the injection device 300, it flows through the sprue (not shown) of the fixed mold 810 and into the cavity space 801 formed between the fixed mold 810 and the movable mold 820. Until the flowing tip of the molding material M reaches the parting surface 830 of the fixed mold 810 and the movable mold 820, even if the clamping force F is low, the fixed mold 810 and the movable mold 820 will not open, and burrs will not occur. Burrs are a phenomenon in which the molding material M leaks between the fixed mold 810 and the movable mold 820 and solidifies.

[0107] If the clamping force F is large and the clamping pressure P2 is greater than the filling pressure P1, when the molding material M reaches the parting surface 830 of the fixed mold 810 and the movable mold 820, the fixed mold 810 and the movable mold 820 will not open. Therefore, the molding material M will not leak and burrs will not occur. Note that the clamping pressure P2 is the value obtained by dividing the clamping force F by the area S of the parting surface 830 (P2 = F / S).

[0108] However, if the fixed mold 810 and the movable mold 820 do not open, it becomes difficult for gas to escape from the inside of the mold device 800 to the outside. If the gas cannot escape, the gas is compressed and heated inside the mold device 800, and there is a possibility of gas burning. Gas burning is a phenomenon in which, when the molding material M flows into the cavity space 801, the gas in the cavity space 801 is compressed and heated, carbonizing the molding material M. Furthermore, if the gas cannot escape, the molding material may not spread evenly within the cavity space 801 of the mold device 800, and the molded product may become a short shot. For this reason, a gap for discharging gas is often provided.

[0109] FIG. 6 is a cross-sectional view showing the mold device 800 according to the present embodiment. In the example shown in FIG. 6, the fixed mold 810 and the movable mold 820 included in the mold device 800 are shown. In the example shown in FIG. 6, a sprue 802 is formed in the fixed mold 810. Also, a runner (not shown) may be provided between the cavity space 801 and the sprue 802.

[0110] In this embodiment, the injection device 300 injects a liquid molding material, and the cavity space 801 is filled with the liquid molding material. The mold device 800 is provided with an air vent 803 for discharging the air that existed in the cavity space 801 before filling and the gas generated from the flow front (flow tip) of the molding material during filling.

[0111] The air vent 803 provided on the parting surface 830 of the mold device 800 is set to a depth that allows air and gas to be discharged but does not allow the molding material to be discharged, that is, it does not form burrs. The depth of the groove of the air vent 803 is determined according to the type of molding material, and for example, it is a groove with a depth of several μm to several tens of μm. In the example shown in FIG. 6, the depth of the groove of the air vent 803 is 20 μm.

[0112] Then, the air that existed in the cavity space 801 before filling and the gas generated from the flow front (flow tip) of the molding material during filling are discharged to the outside of the cavity space 801 through the air vent 803.

[0113] Conventionally, mold devices are often clamped with a large clamping force that does not open the parting surface. However, in such a situation, since there is no gap when filling the molding material, only the air vent allows gas to be discharged. When air and gas concentrate in the air vent, the speed of the air and gas passing through the air vent increases, so the resistance increases when passing through the air vent, making it difficult for air and gas to be discharged. Or as a result of the gas being cooled when passing through the air vent, the components contained in the gas accumulate in the air vent and form mold deposits. As a result of repeated injection molding, the air vent may become blocked.

[0114] Therefore, it is desirable to adjust the clamping force so that the parting surface opens slightly during filling to facilitate the discharge of air and gas, while preventing the molding material from being discharged.

[0115] FIG. 7 is a cross-sectional view showing a state in which the split surface 830 of the mold device 800 according to the present embodiment is open. In the example shown in FIG. 7, the fixed mold 810 and the movable mold 820 included in the mold device 800 are shown.

[0116] In the example shown in FIG. 7, when the molding material M reaches the split surface 830 between the fixed mold 810 and the movable mold 820, a gap is generated between the fixed mold 810 and the movable mold 820 due to the filling pressure.

[0117] In the example shown in FIG. 7, the opening amount of the gap is set to 10 μm. The depth of the groove of the air vent 803 is set to 20 μm. In the example shown in FIG. 7, the sum of the opening amount of 10 μm and the depth of the groove of the air vent 803 of 20 μm, which is 30 μm, becomes the size of the gap generated in the mold device 800. In the present embodiment, the gap is represented by a numerical value in the SI unit system, but it is not limited thereto. Furthermore, it is not necessary to use the size of the gap itself such as dimensions, and an amount related to the size of the gap, or a parameter calculated by substituting an amount related to the size of the gap into a predetermined function may be used, and furthermore, a substitute variable related to the size of the gap may be used.

[0118] In the present embodiment, when the molding material is injected into the mold device 800, in order to suppress the injection of the molding material from the mold device 800, the maximum value allowed as the size of the gap between the fixed mold 810 and the movable mold 820, in other words, the maximum value of the size of the gap is defined as the allowable maximum value (an example of the allowable amount). The allowable maximum value is an example of the allowable amount, and it is not necessary to use the maximum value of the size of the gap itself, and it may be a parameter calculated by substituting an amount related to the size of the gap into a predetermined function, or a substitute variable related to the size of the gap, etc., as long as it represents the allowable amount related to the size of the gap. The allowable maximum value varies depending on the type of the molding material.

[0119] That is, if the sum of the opening amount of the gap and the groove depth of the air vent 803 is equal to or less than the allowable maximum value corresponding to the type of molding material, the discharge of the molding material is suppressed, and air and gas can be discharged from the gap and the air vent 803. In the example shown in FIG. 7, if the allowable maximum value corresponding to the type of molding material is 30 μm or less, the discharge of the molding material from the mold device 800 is suppressed.

[0120] Therefore, the control device 700 according to the present embodiment adjusts the clamping force so that the sum of the opening amount of the gap and the groove depth of the air vent 803 is equal to or less than the allowable maximum value.

[0121] Returning to FIG. 3, the allowable maximum value storage unit 721 of the storage medium 702 stores the allowable maximum value for each molding material used in the injection molding machine 10. FIG. 8 is a diagram showing the table structure of the allowable maximum value storage unit 721 according to the present embodiment. As shown in FIG. 8, the allowable maximum value storage unit 721 stores the molding material (type) and the allowable maximum value in association with each other. For example, the molding material "ABS" has an allowable maximum value of 0.03 mm (= 30 μm). Therefore, when the molding material "ABS" is used, in the example shown in FIG. 7, if the groove depth of the air vent 803 is 20 μm and the opening amount is 10 μm, the sum of the opening amount of the gap and the groove depth of the air vent 803 is 30 μm, so the discharge of the molding material "ABS" from the cavity space 801 is suppressed.

[0122] As shown in FIG. 8, the allowable maximum value differs depending on the type or characteristics of the molding material. Furthermore, the allowable maximum value at which burrs cannot occur and gas burning is not caused differs depending on the viscosity of the molding material (depending on the type and temperature of the resin). In the case of a molding material with high viscosity and low fluidity, the allowable maximum value is about 100 μm, and in the case of a low viscosity resin, it is about 5 μm. Since the allowable maximum value changes depending on the solidification rate of the molding material in the cavity space 801, that is, the temperature of the mold device 800, the temperature of the molding material (melt viscosity), the melting point of the molding material, the injection speed (shear heat, heat transfer from the resin to the mold), and the speed during holding pressure, it is not constant under all conditions. However, in the present embodiment, the numerical values shown in FIG. 8 are used as being substantially the same.

[0123] Returning to FIG. 3, the acquisition unit 713 acquires the detection result from the injection molding machine 10 by a sensor provided in the injection molding machine 10. Further, the acquisition unit 713 acquires the information input by the user from the operation device 750.

[0124] Specifically, the acquisition unit 713 acquires the actual value of the clamping force using a clamping force detector such as the strain detector 141.

[0125] As shown in FIG. 9, the strain detector 141 detects a change in the effective length La of the tie bar 140. The effective length La of the tie bar 140 is the length of the portion that extends according to the clamping force F of the tie bar 140. For example, the effective length La of the tie bar 140 is the length of the portion between the fixed nut 111 and the adjusting nut 182 of the tie bar 140.

[0126] The fixed nut 111 is screwed onto the screw shaft formed at the front end of the tie bar 140 and is held non-rotatably and non-displaceably with respect to the fixed platen 110. On the other hand, the adjusting nut 182 is screwed onto the screw shaft formed at the rear end of the tie bar 140 and is held rotatably and non-displaceably with respect to the toggle support 130. The effective length La of the tie bar 140 can be adjusted by rotating the adjusting nut 182.

[0127] The effective length La of the tie bar 140 changes according to the clamping force F. The strain detector 141 detects the actual value of the clamping force by detecting the change in the length La. The acquisition unit 713 acquires the actual value of the clamping force from the strain detector 141.

[0128] Next, the change in the clamping force of the injection molding machine 10 will be described. FIG. 10 is a diagram showing the change in the clamping force when injecting the molding material in the injection molding machine 10 according to the present embodiment.

[0129] As shown in FIG. 10, after the start of the injection process, until the time t0 when the molding material M reaches the parting surface 830 between the fixed mold 810 and the movable mold 820, the actual value of the clamping force F is stable at the set value. During this period, as shown in FIG. 10, the fixed mold 810 and the movable mold 820 are closed. In this embodiment, the actual value of the clamping force F is stable at the set value, but the actual value of the clamping force F may also be stable at a value shifted from the set value.

[0130] In this embodiment, after closing the cavity space 801, the clamping force before a force is applied in the direction opposite to the clamping force due to the internal pressure of the molding material filled in the cavity space 801 is referred to as the reference clamping force.

[0131] After the start of the injection process and until the time t0, the fixed mold 810 and the movable mold 820 are closed, and the actual value of the clamping force F is stable at the set value, in other words, the reference clamping force.

[0132] At the time t0, when the molding material M reaches the parting surface 830 between the fixed mold 810 and the movable mold 820 and the filling pressure P1 is greater than the clamping pressure P2, the fixed mold 810 and the movable mold 820 are opened by the filling pressure P1. As a result, a gap is formed between the fixed mold 810 and the movable mold 820 as shown in FIG. 7. The effective length La of the tie bar 140 increases by the size of the gap, and the actual value of the clamping force F increases compared to the reference clamping force.

[0133] Therefore, the increase width ΔF of the actual value of the clamping force F corresponds to the size of the gap formed between the fixed mold 810 and the movable mold 820. That is, the larger the size of the gap, the larger the increase width ΔF.

[0134] In this embodiment, the maximum clamping force is referred to as the peak clamping force. In the example shown in FIG. 10, at the time t2, the actual value of the clamping force detected by the tie bar strain detector 141 becomes the peak clamping force.

[0135] The control device 700 according to this embodiment adjusts the reference clamping force so that the molding material is not discharged from the mold device 800 even when the mold device 800 is opened by the peak clamping force.

[0136] Therefore, the acquisition unit 713 acquires information indicating the groove depth (an example of the gap amount indicating the size of the gap) of the vent (an example of the gap) 803 of the mold device 800 attached to the injection molding machine 10. The information indicating the groove depth of the vent 803 may be received, for example, as an input from the user. These are examples of the gap amount, and it is not necessary to use the size of the gap itself such as dimensions. Instead, a parameter calculated by substituting an amount related to the size of the gap into a predetermined function, or a substitute variable related to the size of the gap may be used.

[0137] In addition, when adjusting the clamping force, the acquisition unit 713 refers to the allowable maximum value storage unit 721 to acquire the allowable maximum value corresponding to the type of molding material used by the injection molding machine 10. Note that the acquisition unit 713 may receive, for example, as an input from the user, the type of molding material used by the injection molding machine 10. Further, the acquisition unit 713 may acquire the allowable maximum value input by the user without referring to the allowable maximum value storage unit 721.

[0138] Then, when the molding material is injected into the mold device 800 closed by the clamping device 100, the adjustment unit 714 adjusts the reference clamping force of the clamping device 100 so as to suppress the sum of the opening amount between the fixed mold 810 and the movable mold 820 caused by the injection of the molding material and the groove depth of the air vent 803 from becoming larger than the allowable maximum value. In this embodiment, the maximum value of the gap size, which is an example of the allowable amount, the opening amount between the fixed mold 810 and the movable mold 820, which is an example of the opening amount, and the groove depth of the air vent 803, which is an example of the gap amount, are all expressed in numerical values of the metric system of the SI unit system. For this reason, in this embodiment, the adjustment unit 714 simply compares the sum of the opening amount between the fixed mold 810 and the movable mold 820 and the groove depth of the air vent 803 with the allowable maximum value, but the conditions for adjusting the reference clamping force are not limited to the result of the simple comparison. For example, one or more of the opening amount and the groove depth may be weighted using a coefficient, or the result calculated by substituting one or more of the opening amount and the groove depth into a function or the like may be used. As long as the value based on the gap amount indicating the gap size and the opening amount indicating the gap size between the fixed mold 810 and the movable mold 820 is adjusted to satisfy the conditions by the allowable amount.

[0139] For example, when using an ABS resin, as shown in FIG. 8, the allowable maximum value is 30 μm. When the groove depth of the air vent of the mold device 800 is 20 μm, even if the gap between the fixed mold 810 and the movable mold 820 is opened by 10 μm, no burrs will occur. On the other hand, when the groove depth of the air vent of the mold device 800 is 10 μm, no burrs will occur even if it is opened by 20 μm.

[0140] Therefore, specifically, the adjustment unit 714 adjusts the clamping force of the clamping device 100 so as to suppress the sum of the opening amount corresponding to the peak clamping force and the groove depth of the air vent from becoming larger than the allowable maximum value.

[0141] The relationship between the stress σ generated in the tie bar 140 and the amount of strain ε generated in the tie bar 140 can be expressed by Equation (1). Here, let E be the Young's modulus of the tie bar 140. The stress σ is the stress when the clamping force is the highest, in other words, the stress at the peak clamping force. Let ΔL be the opening amount corresponding to the peak clamping force, and let La be the effective length of the tie bar 140.

[0142] σ = Eε = E·ΔL / La ……(1)

[0143] The stress σ can be expressed as Fd / A. Here, the force Fd is the difference between the peak clamping force and the reference clamping force. The area A is the total cross-sectional area of the tie bar 140 (in the case of 4 tie bars, it is the cross-sectional area per bar × 4). Therefore, Equation (2) can be derived.

[0144] Fd / A = E·ΔL / La ……(2)

[0145] As shown in Equation (2), the difference force Fd between the peak clamping force and the reference clamping force, that is, the change amount of the clamping force when the molding material is injected, corresponds to the opening amount ΔL of the mold device 800.

[0146] Therefore, the adjustment unit 714 according to the present embodiment can adjust the clamping force based on the opening amount ΔL by adjusting the reference clamping force based on the change amount (the difference force Fd between the peak clamping force and the reference clamping force) of the actual value of the clamping force detected by the tie bar strain detector 141 when the molding material is injected.

[0147] From Equation (2), the opening amount ΔL of the mold device 800 can be calculated from "FdLa / AE". And the adjustment unit 714 according to the present embodiment determines whether the opening amount ΔL of the mold device 800 is an amount capable of suppressing the discharge of the molding material. Specifically, if the opening amount ΔL is less than or equal to L1 - L2, the discharge of the molding material can be suppressed. L1 is the allowable maximum value, and L2 is the depth of the groove of the vent 803 of the mold device 800. From the relationship between Equation (2) and "L1 - L2", Equation (3) can be derived.

[0148] L1 - L2 ≥ ΔL = FdLa / AE ……(3)

[0149] The following formula (4) is derived from formula (3).

[0150] Fd ≦ (L1 - L2)AE / La …… (4)

[0151] When the force Fd of the difference between the peak clamping force and the reference clamping force satisfies formula (4), the opening amount ΔL is such that the discharge of the molding material can be suppressed. In other words, if the adjustment unit 714 determines whether or not formula (4) is satisfied, it can determine whether or not the opening amount ΔL is an opening amount that can suppress the discharge of the molding material.

[0152] By the way, if the reference clamping force is increased, the difference in the force Fd of the difference between the peak clamping force and the reference clamping force becomes smaller. If the reference clamping force is decreased, the difference in the force Fd of the difference between the peak clamping force and the reference clamping force becomes larger.

[0153] That is, when the adjustment unit 714 does not satisfy formula (4), it may be set so that the reference clamping force becomes larger. In this way, the adjustment unit 714 repeats the adjustment of the reference clamping force so as to satisfy formula (4). Thereby, the reference clamping force can be set so as to suppress the generation of burrs.

[0154] Furthermore, the adjustment unit 714 according to the present embodiment also adjusts the reference clamping force so that the force Fd of the difference between the peak clamping force and the reference clamping force approaches (L1 - L2)AE / La.

[0155] That is, since the force Fd of the difference between the peak clamping force and the reference clamping force becomes smaller when the reference clamping force is set high, formula (4) can be satisfied. However, when the reference clamping force is high, it becomes difficult for the mold device 800 to open. That is, the control device 700 can discharge air and gas from the gap opened by the mold device 800 and suppress the discharge of the molding material from the air vent 803 of the mold device 800 by adjusting the reference clamping force low while satisfying formula (4).

[0156] For example, as the force Fd of the difference between the peak clamping force and the reference clamping force approaches (L1 - L2)AE / La, as shown in FIG. 7, the gap between the fixed mold 810 and the movable mold 820 opens, and air and gas are discharged from the gap, but the discharge of the molding material is suppressed. That is, the escape property of air and gas is improved, and burrs can be suppressed.

[0157] Therefore, the adjustment unit 714 according to the present embodiment adjusts the clamping force of the mold clamping device 100 so that the sum of the opening amount and the groove depth of the air vent 803 is suppressed from becoming larger than the allowable maximum value and approaches the allowable maximum value.

[0158] Actually, it is not limited to the determination of conditions for comparing the sum of the opening amount and the groove depth of the air vent 803 as described above with the allowable maximum value. For example, it may be calculated using a coefficient or the like as in Equation (4). This is because the actual opening amount becomes larger due to deflection or the like occurring in the configuration of the injection molding machine 10 compared to the opening amount ΔL corresponding to the peak clamping force. Therefore, the adjustment unit 714 adjusts the reference clamping force in consideration of the allowable error (coefficient) corresponding to the injection molding machine 10 and the mold device 800 or the like. The setting regarding the allowable error (coefficient) may be input from the user, for example. In the present embodiment, a parameter called "sensitivity" is used as the setting regarding the allowable error (coefficient).

[0159] The adjustment unit 714 according to the present embodiment calculates the force Fd of the difference between the peak clamping force and the reference clamping force for each shot from the actual value of the clamping force derived from the tire distortion detector 141. Then, when the calculated force Fd of the difference between the peak clamping force and the reference clamping force is included in the target range (an example of a predetermined range), the adjustment of the reference clamping force is terminated. The target range is determined based on (L1 - L2)AE / La and the sensitivity described later. A specific method for setting the target range will be described later.

[0160] When the difference between the peak clamping force and the reference clamping force is not included in the target range, the adjustment unit 714 adjusts the reference clamping force.

[0161] The output control unit 715 outputs information to an external device. For example, the output control unit 715 outputs a display screen to the display device 760.

[0162] The log information processing unit 716 performs processing related to log information. For example, the log information processing unit 716 may determine whether an abnormality has occurred based on the log information.

[0163] FIG. 11 is a diagram showing an example of a setting screen output by the output control unit 715 according to the present embodiment to the display device 760. As shown in FIG. 11, on the setting screen 2100, there are shown a selection column 2101 for the type of molding material, an allowable maximum value display column 2102, a setting column 2103 for the maximum vent depth of the mold device, a sensitivity selection column 2104, an adjustment switch selection column 2105, and a display column 2106 for the gap calculation value at the most recent molding.

[0164] The selection column 2101 for the type of molding material is, for example, a pull-down menu, and a list of the types of molding materials is displayed so that selection is possible. In the example shown in FIG. 11, a selection of "ABS" has been received from the user.

[0165] The allowable maximum value display column 2102 displays the allowable maximum value corresponding to the type of molding material selected in the selection column 2101 for the type of molding material, by the output control unit 715. The allowable maximum value can be derived from the selected type of molding material and the allowable maximum value storage unit 721.

[0166] Note that when no selection of a molding material is received in the selection column 2101 for the type of molding material, the allowable maximum value display column 2102 may be a text input column, and the user may directly input the allowable maximum value.

[0167] The setting column 2103 for the maximum vent depth of the mold device is a text input column into which the user can input, and receives an input from the user of the maximum depth of the groove of the air vent 803 provided in the mold device 800.

[0168] The sensitivity selection field 2104 is, for example, a pull-down menu that accepts the selection of sensitivity for setting the reference clamping force. The sensitivity is a parameter for deriving the allowable error (coefficient) of the mold device 800 attached to the injection molding machine 10. The sensitivity can be selected from, for example, "high", "medium", and "low". The allowable error increases in the order of "high", "medium", and "low". For example, if the mold device 800 has high precision and sufficient thickness (in other words, it is not easily deformed), "high" can be set. If the precision of the mold device 800 is low and it is thin (in other words, it is easily deformed), "low" can be set.

[0169] Then, based on the accepted sensitivity and (L1 - L2)AE / La, the adjustment unit 714 sets the target range. Note that the method of setting the target range is not limited to the method shown below, and an appropriate target range may be set according to the characteristics of the mold device 800 and the like.

[0170] For example, when the adjustment unit 714 accepts the selection of "high", it sets "(L1 - L2)AE / La" × 0.8 or more and "(L1 - L2)AE / La" × 0.95 or less as the target range.

[0171] For example, when the adjustment unit 714 accepts the selection of "medium", it sets "(L1 - L2)AE / La" × 0.6 or more and "(L1 - L2)AE / La" × 0.90 or less as the target range.

[0172] For example, when the adjustment unit 714 accepts the selection of "low", it sets "(L1 - L2)AE / La" × 0.4 or more and "(L1 - L2)AE / La" × 0.80 or less as the target range.

[0173] The adjustment switch selection field 2105 is, for example, a pull-down menu that accepts the selection of whether to adjust the reference clamping force. For example, either "on" or "off" can be selected. When the selection of "on" is accepted, the control device 700 adjusts the reference clamping force. When the selection of "off" is accepted, the control device 700 suppresses the adjustment of the reference clamping force.

[0174] The display column 2106 for the gap calculation value during the most recent molding displays the calculated value of the gap of the mold device 800, which is calculated based on the actual value of the clamping force detected by the tie bar strain detector 141 and the maximum depth of the groove of the air vent 803 during the most recent injection molding.

[0175] For example, each time injection molding is performed, the adjustment unit 714 derives "FdLa / AE + L2" as the calculated value of the gap of the mold device 800, and the output control unit 715 outputs the calculated value of the gap of the mold device 800 to the display column 2106 for the gap calculation value during the most recent molding.

[0176] Note that FIG. 11 shows an example of the setting screen, and is not limited to the display items and display modes. As the display item, for example, the allowable opening amount obtained by subtracting the maximum depth of the groove of the air vent 803 from the allowable maximum value may be displayed. The allowable opening amount is calculated by the adjustment unit 714, for example, for each shot.

[0177] Next, a procedure of the process for adjusting the reference clamping force, which is executed by the control device 700 according to the present embodiment, will be described. FIG. 12 is a flowchart showing the procedure of the process for adjusting the reference clamping force, which is executed by the control device 700 according to the present embodiment.

[0178] First, the output control unit 715 outputs the setting screen to the display device 760 (S2201). Thereby, the setting screen 2100 shown in FIG. 11 is displayed.

[0179] The acquisition unit 713 determines whether or not a selection of the type of molding material has been received from the selection column 2101 for the type of molding material on the setting screen 2100 (S2202). When the acquisition unit 713 determines that a selection has been received (S2202: YES), the acquisition unit 713 refers to the allowable maximum value storage unit 721 to specify the allowable maximum value corresponding to the type of molding material for which the selection has been received (S2203). Then, the output control unit 715 displays the specified allowable maximum value in the allowable maximum value display column 2102.

[0180] When the acquisition unit 713 determines that the selection in the selection column 2101 for the type of molding material on the setting screen has not been received (S2202: NO), the acquisition unit 713 specifies the numerical value received as the input for the allowable maximum value display column 2102 as the allowable maximum value (S2204).

[0181] The acquisition unit 713 receives the selection of sensitivity from the sensitivity selection column 2104 (S2205).

[0182] The adjustment unit 714 calculates the target range of the difference between the reference clamping force and the peak clamping force based on the allowable maximum value, the maximum depth of the vent groove of the mold device 800, and the sensitivity (S2206). The calculation method of the target range is as described above, and the explanation is omitted.

[0183] Then, the acquisition unit 713 determines whether or not the selection of "ON" has been received for the adjustment switch selection column 2105 (S2207). In a state where the selection of "ON" has not been received, in other words, the selection of "OFF" has been received (S2207: NO), it waits until the selection of "ON" is received.

[0184] When the acquisition unit 713 determines that the selection of "ON" has been received for the adjustment switch selection column 2105 (S2207: YES), the control device 700 performs injection molding using the set reference clamping force (S2208). Note that at the first time, an initial value is set as the reference clamping force. Note that the initial value may be an arbitrary value according to the embodiment.

[0185] The adjustment unit 714 calculates the differential force Fd between the reference clamping force and the peak clamping force from the actual value of the clamping force detected by the tire strain detector 141 (S2209). At this time, the adjustment unit 714 also calculates the calculated value of the gap of the mold device 800. Then, the output control unit 715 displays the calculated value of the gap of the mold device 800 in the display column 2106 for the gap calculated value at the most recent molding.

[0186] Then, the adjustment unit 714 determines whether or not the calculated differential force Fd is included within the target range (S2210).

[0187] When the adjustment unit 714 determines that the calculated differential force Fd is not within the target range (S2210: NO), it determines whether the calculated differential force Fd is less than the lower limit value of the target range (S2210). When it is determined that the force is less than the lower limit value of the target range (S2210: YES), the reference clamping force is decreased by a predetermined value (for example, 10 kN) (S2211).

[0188] On the other hand, when the adjustment unit 714 determines that the calculated differential force Fd is not less than the lower limit value of the target range, that is, when it is determined that the force is not less than the target range and is not within the target range, so it is greater than the upper limit value of the target range (S2210: NO), the reference clamping force is increased by a predetermined value (for example, 10 kN) (S2212).

[0189] After the processing of S2211 or S2212, the control device 700 executes injection molding again using the set reference clamping force (S2208). The subsequent processing is the same as described above, and the processing of S2209 is performed.

[0190] On the other hand, in S2210, when the adjustment unit 714 determines that the calculated differential force Fd is within the target range (S2210: YES), it ends the process on the assumption that the adjustment of the reference clamping force is completed.

[0191] After the adjustment of the reference clamping force is completed by the above-described processing, the control device 700 according to the present embodiment performs injection molding using the reference clamping force. At that time, the opening amount of the mold device 800 may be monitored. The setting for monitoring may be performed on the log information screen.

[0192] In this embodiment, when the "ON" selection is received for the adjustment switch selection field 2105 on the setting screen 2100 in FIG. 11, the case of adjusting the reference clamping force according to whether the differential force Fd between the reference clamping force and the peak clamping force is within the target range has been described. However, this embodiment does not limit the method of adjusting the reference clamping force only when the "ON" selection is received for the adjustment switch selection field 2105. For example, even when there is no adjustment switch selection field 2105, the reference clamping force may be automatically adjusted according to whether the differential force Fd between the reference clamping force and the peak clamping force is within the target range.

[0193] As a further modification, when the differential force Fd between the reference clamping force and the peak clamping force is not within the target range, the output control unit 715 outputs an inquiry screen to the display device 760 as to whether the reference clamping force may be changed. The inquiry screen displays the current reference clamping force, a message for inquiring whether the current reference clamping force may be changed, an "OK" button, and a "Cancel" button. Then, when the acquisition unit 713 receives the pressing of the "OK" button from the user via the operation device 750, the adjustment unit 714 adjusts the reference clamping force. The method of adjusting the reference clamping force is the same as the method described above, and the description thereof is omitted. On the other hand, when the acquisition unit 713 receives the pressing of the "Cancel" button from the user via the operation device 750, the process for adjusting the reference clamping force by the adjustment unit 714 is terminated, and the current reference clamping force is maintained. In this modification, since the reference clamping force is adjusted only when permission is received from the user, misadjustment of the reference clamping force can be suppressed, and improvement in the quality of the molded product can be realized.

[0194] Returning to the embodiment, FIG. 13 is a diagram illustrating a log information screen output by the output control unit 715 according to this embodiment. The log information screen shown in FIG. 13 displays log information related to injection molding. Further, in the log information screen, the log information processing unit 716 can set for storing the log information.

[0195] In the log information screen 2300 shown in FIG. 13, the total number 2311, the number of non-defective products 2312, the number of defective products 2313, the number of rejects 2314, the logging button 2315, the monitoring setting button 2316, the save button 2317, the update button 2318, the statistics list 2320, and the performance list 2330 are shown.

[0196] The statistics list 2320 represents statistical information (for example, average, range, maximum, minimum, standard deviation) for each of the setting columns 2321 to 2327. The contents shown in the setting columns 2321 to 2327 can be set by the user. In the present embodiment, it is possible to display, monitor, and save log information for the items shown in the setting columns 2321 to 2327. Note that the monitoring in the present embodiment represents a determination as to whether a product is non-defective based on a predetermined standard.

[0197] The statistical information is information calculated based on the performance values (an example of parameters) obtained each time a molded product is manufactured by performing injection molding with the injection molding machine 10. For example, in the statistics list 2320, the average, range, maximum, minimum, and standard deviation calculated for each of the setting columns 2321 to 2327 are included. Note that the present embodiment shows an example of statistical information, and statistical information other than the average, range, maximum, minimum, and standard deviation, such as an integral value, may be used. Also, the items for which statistical information is calculated are not limited to the items set in the setting columns 2321 to 2327, and other items may be used.

[0198] The output control unit 715 calculates statistical information based on the performance values (an example of parameters) obtained by various sensors by injection molding within the range shown in the performance list 2330. Then, the output control unit 715 represents the calculated statistical information in the statistics list 2320.

[0199] "Monitoring", "monitoring value", and "range" in the statistics list 2320 are used as information for determining whether a molded product in the corresponding setting column is defective.

[0200] When the monitoring of the statistical list 2320 is "off", the control device 700 does not perform monitoring, and when it is "on", it indicates that the control device 700 performs monitoring. When it is "on", the control device 700 determines whether the measured actual value in the item indicated in the setting column meets the criteria indicated by the "monitoring value" and "range" (for example, whether it is included within the "range" with the "monitoring value" as the median). As another example, the control device 700 may determine whether the set monitoring value meets the criteria based on the set plus tolerance and minus tolerance with the set monitoring value as the median, or whether it meets the criteria of the set upper limit value and lower limit value. Note that any method may be used for the actual value monitoring method regardless of the method described above. The switching of the monitoring is performed by the monitoring setting button 2316.

[0201] The "defects" in the statistical list 2320 indicate the number of molded products that do not meet the criteria indicated by the "monitoring value" and "range".

[0202] The "cycle time" in the setting column 2321, the "filling time" in the setting column 2322, and the "measurement time" in the setting column 2323 are items set to monitor the time required for the cycle, filling, and measurement.

[0203] The "V-P switching position" in the setting column 2324 is an item set to monitor the position of the screw 330 (V / P switching position) when switching from the filling process to the holding pressure process.

[0204] The "maximum clearance value" in the setting column 2325 is an item set to monitor the sum of the maximum depth of the groove of the air vent 803 of the mold device 800 and the opening amount corresponding to the peak mold clamping force of the maximum clearance of the mold device 800.

[0205] For example, the output control unit 715 displays the "FdLa / AE + L2" calculated by the adjustment unit 714 in the setting column 2325 as a numerical value indicating the sum of the maximum depth of the groove of the air vent 803 and the opening amount corresponding to the peak mold clamping force. Note that "FdLa / AE + L2" is based on the above-described formula (3).

[0206] The "filling peak pressure" in the setting column 2326 is an item set to monitor the peak value of the pressure when filling the molding material.

[0207] The "opening amount" in the setting column 2327 is an item set to monitor the opening amount corresponding to the peak clamping force.

[0208] For example, the output control unit 715 displays the "FaLa / AE" calculated by the adjustment unit 714 in the setting column 2327 as a numerical value indicating the opening amount corresponding to the peak clamping force. Note that "FaLa / AE" is based on the above-described formula (3).

[0209] Note that the setting columns 2321 to 2327 can be changed to items that the user wants to monitor. The description of the changing method is omitted.

[0210] For example, since the "maximum gap value" in the setting column 2325 is set to "on" for monitoring, the log information processing unit 716 monitors whether an abnormality has occurred. In the example shown in FIG. 13, the monitoring value "30.00" is set as the allowable maximum value. Then, the log information processing unit (an example of a processing unit) 716 monitors whether the "maximum gap value" (the sum of the opening amount and the maximum depth of the groove of the air vent 803) is greater than the monitoring value "30.00" (an example of the allowable amount). For example, the log information processing unit 716 determines that it is abnormal when the "maximum gap value" is greater than the monitoring value "30.00". Then, when the "maximum gap value" calculated for each shot is greater than the monitoring value "30.00", the log information processing unit 716 counts it as a defective product, assuming that there is a possibility of burr generation.

[0211] As another example, since the "opening amount" in the setting column 2327 is set to "on" for monitoring, the log information processing unit 716 determines whether an abnormality has occurred. In the example shown in FIG. 13, a monitoring value "20.00" is set as the maximum opening amount of the mold device 800. For example, the log information processing unit 716 monitors whether the "opening amount" is greater than the monitoring value "20.00". For example, the log information processing unit 716 determines that it is abnormal when the "opening amount" is greater than the monitoring value "20.00". Then, when the "opening amount" calculated for each shot is greater than the monitoring value "20.00", the log information processing unit 716 counts it as a defective product on the assumption that burrs may have occurred.

[0212] In FIG. 13, for the sake of explanation, an example in which the "maximum clearance value" and the "opening amount" are set in the setting column is shown, but the method of setting the "maximum clearance value" and the "opening amount" is not limited, and only one of the "maximum clearance value" and the "opening amount" may be used.

[0213] The performance list 2330 represents a list of setting information (for example, set values) in the items set in the setting columns 2321 to 2327 or performance values measured by various sensors for each shot. The items set in the setting columns 2321 to 2327 are set from "CH1" to "CH7". Also, for each shot, information indicating the shot, such as the "shot number", the "time" of injection molding, and the "discrimination" of injection molding, is associated.

[0214] The logging button 2315 is a button that accepts a selection of whether to save the performance values shown in the performance list 2330 as log information. When the logging button 2315 is pressed (displayed as "Data Logging ON"), the log information processing unit 716 stores the information shown in the performance list 2330 (for example, performance values from various sensors) and the like in the storage medium 702 as log information.

[0215] That is, in the present embodiment, the maximum value of the gap of the mold device 800 for each shot (the sum of the maximum depth of the groove of the vent 803 of the mold device 800 and the opening amount corresponding to the peak mold clamping force), the opening amount corresponding to the peak mold clamping force, etc. can be stored in the storage medium 702 as log information.

[0216] The monitoring setting button 2316 is a button for receiving whether to monitor according to the items to be monitored in the statistical list 2320. When the monitoring setting button 2316 is pressed (displayed as "Monitoring ON"), it monitors whether it is a defective product for each shot and includes the monitoring result in the log information. When the monitoring setting button 2316 is pressed, the monitoring for each of the setting columns 2321 to 2327 in the statistical list 2320 can be switched between "OFF" and "ON".

[0217] The save button 2317 is a button for receiving whether to save the statistical values (for example, average, range, maximum, minimum, standard deviation, etc.) for each of the setting columns 2321 to 2327. When the save button 2317 is pressed, the log information processing unit 716 saves the statistical values for each of the setting columns 2321 to 2327 and the performance values shown in the performance list 2330 in the storage medium 702 as log information. In the present embodiment, an example of saving the statistical values and the performance values is described, but the saving of the statistical values and the performance values is not limited. For example, when settings are shown in the performance list 2330, the log information processing unit 716 may save the setting values together. Furthermore, even if no setting values are shown in the performance list 2330, the log information processing unit 716 may save the setting values in association with the performance values shown in the performance list 2330.

[0218] The update button 2318 is a button for receiving whether to update the statistical list 2320 and the performance list 2330 every time the injection molding by the injection molding machine 10 is completed. When the update button 2318 is pressed (displayed as "Always"), the statistical list 2320 and the performance list 2330 are updated every time the injection molding by the injection molding machine 10 is completed.

[0219] The total number 2311 indicates the number of molded products molded by the injection molding machine 10. The number of non-defective products 2312 indicates the number of molded products determined to be non-defective based on "monitoring", "monitoring value", and "range". The number of defective products 2313 indicates the number of molded products determined to be defective based on "monitoring", "monitoring value", and "range". The number of rejects 2314 indicates the number of rejected molded products.

[0220] As described above, when the output control unit 715 of the control device 700 produces a molded product from a molding material by the injection molding machine 10, for each molded product, the actual value (an example of a detection result) detected by various sensors in the process of producing the molded product is displayed on the actual result list 2330 of the display device 760.

[0221] For example, in the actual result list 2330, "CH5" corresponds to the "maximum gap value". That is, in the column 2331 of "CH5" in the actual result list 2330, for each shot, the maximum value of the gap of the mold device 800 (the sum of the maximum depth of the groove of the air vent 803 of the mold device 800 and the opening amount corresponding to the peak clamping force) is displayed as the actual value.

[0222] As another example, in the actual result list 2330, "CH7" corresponds to the "opening amount". That is, in the column 2332 of "CH7" in the actual result list 2330, for each shot, the opening amount of the mold device 800 when the peak clamping force is detected is displayed as the actual value.

[0223] Furthermore, when the logging button 2315 is pressed, the log information processing unit 716 stores the information shown in the actual result list 2330 (for example, the actual values from various sensors) and the like in the storage medium 702 as log information. Therefore, the maximum value of the gap of the mold device 800 and the opening amount of the mold device 800 when the peak clamping force is detected are stored in the storage medium 702 as log information. Accordingly, the opening amount of the mold device 800 can be managed for each molded product.

[0224] In the log information screen 2300 shown in FIG. 13, for each shot, the "maximum gap value" and the "opening amount" are displayed, so that the user can visually check whether there is a possibility that burrs are generated on the molded product.

[0225] The screen for the output control unit 715 to monitor is not limited to the log information screen as shown in FIG. 13.

[0226] FIG. 14 is a diagram illustrating a gap amount display screen output by the output control unit 715 according to the present embodiment. In the gap amount display screen shown in FIG. 14, the gap amount for each shot is displayed by a line 2401. The gap amount for each shot is the sum of the maximum depth of the groove of the vent 803 of the mold device 800 and the opening amount corresponding to the peak clamping force.

[0227] Furthermore, a threshold value 2402 serving as a reference for discharging the molding material from the mold device 800 can be set on the gap amount display screen. In the example shown in FIG. 14, "30.00" is set as the threshold value.

[0228] Then, by referring to the gap amount display screen, the user can confirm in chronological order whether the waveform indicating the gap amount for each shot exceeds the threshold value 2402. That is, the user can recognize at which timing there is a possibility that defective products with burrs are generated.

[0229] Note that in the present embodiment, an example of performing calculations has been described assuming that the amount of change in the clamping force detected by the strain detector 141 corresponds to the opening amount between the fixed mold 810 and the movable mold 820 caused by the injection of the molding material. However, the present embodiment does not limit the method of calculating the opening amount between the fixed mold 810 and the movable mold 820 caused by the injection of the molding material as corresponding to the amount of change in the clamping force detected by the strain detector 141, and detection results of other sensors (for example, a distance sensor capable of detecting the opening amount) may be used.

[0230] (Second Embodiment) In the above-described embodiment, an example in which the control device 700 of the injection molding machine 10 adjusts the clamping force of the mold device 800 has been described. However, the above-described embodiment does not limit the method by which the control device 700 of the injection molding machine 10 adjusts the clamping force of the mold device 800. The second embodiment is an example in which a group management device (an example of a control device) that controls a plurality of injection molding machines 10 performs management.

[0231] For example, when using mold devices 800 of the same shape and the same type of molding material in a plurality of injection molding machines 10, the group management device collectively adjusts the reference clamping force for each of the plurality of injection molding machines 10. For example, the group management device uses any one of the plurality of injection molding machines 10 to perform the same control as in the above-described embodiment.

[0232] In the present embodiment, since the group management device collectively adjusts the reference clamping force for each of the plurality of injection molding machines 10, the work load can be reduced.

[0233] <Function> The control device 700 according to the present embodiment performs the above-described processing. Therefore, the user can input the selection of the type of molding material or the allowable maximum value, and the maximum depth of the vent groove of the mold device 800, and the control device 700 can adjust to a reference clamping force such that air and gas are discharged and no burrs are generated without checking whether there are burrs on the molded product. Therefore, the user does not need to manually adjust the clamping force while checking whether burrs are generated on the molded product, and thus the operation burden can be reduced.

[0234] Conventionally, it has been difficult to adjust the reference clamping force without being a skilled person, but in the present embodiment, since the control device 700 performs the above-described processing, the quality of the molded product can be made equal regardless of whether the user is a skilled person or not. Therefore, an improvement in the quality of the molded product can be realized.

[0235] The control device 700 according to this embodiment adjusts the reference clamping force so that it falls within the target range, thereby adjusting the amount of clearance generated on the parting surface 830 of the mold device 800 during filling to such an extent that air and gas can be discharged, but the molding material cannot be discharged. Therefore, since air and gas are easily discharged from the clearance generated on the parting surface 830, it is possible to suppress the concentration of air and gas discharge at the vent 803. Therefore, it is possible to reduce the occurrence of mold deposits at the vent 803, so the time until the vent 803 is blocked can be extended. Therefore, the interval for cleaning the mold device 800 can be extended. Therefore, the working efficiency can be improved and the cleaning burden can be reduced.

[0236] By the way, as a method for detecting the opening amount of the mold device, there is a method of installing a sensor capable of detecting the amount of clearance of the parting surface between the movable mold and the fixed mold of the mold device. And a method can be considered in which the control device adjusts the clearance amount of the mold device based on the detection result of the sensor. When using this method, it is necessary to install sensors for the number of mold devices. Also, when replacing the sensor on the mold device, adjustment of the sensor is required, so it takes adjustment burden and time. Further, since the injection molding machine generates vibration due to injection molding or opening and closing of the mold device, there is a possibility of positional deviation between the mold device and the sensor, that is, a deviation in the detection result.

[0237] On the other hand, in the above-described embodiment, since the strain detector 141 is installed on the tie bar 140, it is not necessary to reinstall and readjust the sensor when replacing the mold device 800. Furthermore, since the amount of strain of the tie bar 140 is detected, the influence of displacement due to vibration can be reduced. Therefore, the work burden on the user can be reduced and the occurrence of errors due to vibration can be suppressed. Therefore, the detection accuracy can be improved, and the occurrence of molding defects can be suppressed.

[0238] Furthermore, a method of calculating the opening amount of the parting surface of the mold device based on the filling pressure of the mold device can be considered. When calculating the opening amount of the parting surface of the mold device based on the filling pressure, there are many factors that determine the magnitude of the filling pressure, and it often does not directly relate to the opening amount of the mold device. Factors that determine the magnitude of the filling pressure include the average temperature of the molding material, the magnitude of the temperature unevenness of the molding material, the density of the molding material, the temperature of the cavity runner part of the mold device, the closed state during screw filling, the amount of drooling (flash) before injection, etc. Due to these factors, the filled resin viscosity or pressure loss easily changes, resulting in a change in the filling pressure. Furthermore, what is added with the factors of the rigidity of the mold clamping device and the rigidity of the mold device becomes the clearance amount of the parting surface of the mold device. When these factors change, a difference occurs between the force related to the cavity space and the filling pressure. For this reason, it is considered that calculating the opening amount based on the filling pressure results in a large error.

[0239] In contrast, the control device 700 according to the above-described embodiment performs an operation based on the strain amount of the tie bar 140 to obtain the clearance amount of the parting surface 830 of the mold device 800. In this method, since there are fewer factors than the filling pressure and deviation is less likely to occur, it is possible to improve the accuracy of adjusting the reference mold clamping force.

[0240] Also, a method of installing a pressure sensor in the cavity space and adjusting the reference mold clamping force based on the detection result of the pressure sensor can be considered. However, depending on the molding material, the cavity space can reach nearly 200°C, so there are few available sensor types. Furthermore, since it repeatedly becomes a high-pressure state during injection molding, in such a high-load environment, the risk of abnormalities occurring in the pressure sensor increases. When the pressure sensor fails, it is necessary to disassemble the mold device in order to remove the pressure sensor and install a new one. For this reason, it requires a workload and working time. Also, since it is necessary to install a pressure sensor for each mold device, the cost of the mold device increases.

[0241] In contrast, the control device 700 according to the present embodiment uses the detection result of the tie bar strain detector 141. Therefore, even when there are multiple mold devices 800, it can be measured by one tie bar strain detector 141 attached to the injection molding machine 10, so the cost can be reduced. Further, since the tie bar strain detector 141 is attached to the tie bar 140, the load of temperature and pressure can be reduced compared with the case of using a pressure sensor. Thus, the risk of occurrence of abnormalities can be reduced, and replacement can be easily performed. Therefore, since abnormalities can be suppressed, the detection accuracy can be improved, and the occurrence of molding defects can be suppressed. Further, since replacement can be easily performed, the work burden can be reduced.

[0242] The control device 700 according to the present embodiment calculates the amount of gap generated in the parting surface 830 in consideration of the maximum depth of the groove of the air vent 803. Since the maximum depth of the groove of the air vent 803 and the amount of gap are in the same unit of distance, conversion or calculation is not required, so the occurrence of errors due to conversion or calculation can be suppressed, and improvement in accuracy can be realized. That is, considering the depth of the groove of the air vent 803, it is possible to suppress the discharge of the molding material and realize an improvement in accuracy when adjusting the reference clamping force that can discharge air and gas. That is, the control device 700 according to the present embodiment can adjust the reference clamping force in any case, for example, when the air vent 803 is not provided in the mold device 800 and when the air vent 803 having a depth close to the upper limit of the allowable maximum value is provided in the mold device 800.

[0243] As described above, the embodiment of the control device of the injection molding machine according to the present invention has been described, but the present invention is not limited to the above embodiment and the like. Within the scope described in the claims, various changes, modifications, substitutions, additions, deletions, and combinations are possible. Naturally, they also belong to the technical scope of the present invention.

Description of Reference Numerals

[0244] 10 Injection molding machine 100 Clamping device 141 Tie bar strain detector 700 Control Device 701 CPU 711 Clamping Control Unit 712 Injection Control Unit 713 Acquisition Unit 714 Adjustment Unit 715 Output Control Unit 716 Log Information Processing Unit 702 Storage Medium 721 Allowable Maximum Value Storage Unit 800 Mold Device 803 Air Vent 810 Fixed Mold 820 Movable Mold 830 Split Surface

Claims

1. A control device for controlling an injection molding machine including a mold device having a fixed mold and a movable mold, a mold clamping device for opening and closing the fixed mold and the movable mold, and an injection machine for injecting a molding material into the mold device, wherein when the molding material is injected into the mold device, an allowable amount that is allowed as the size of the gap between the fixed mold and the movable mold is obtained to suppress discharge of the molding material from the mold device, an acquisition unit that obtains a gap amount indicating the size of a gap provided for discharging gas between the fixed mold and the movable mold; when the molding material is injected into the mold device closed by the mold clamping device, an adjustment unit that adjusts the mold clamping force of the mold clamping device so that a value based on the opening amount indicating the size of the gap between the fixed mold and the movable mold generated by the injection of the molding material and the gap amount satisfies the condition based on the allowable amount; A control device for an injection molding machine comprising the above.

2. The adjustment unit adjusts the mold clamping force of the mold clamping device on the mold device so that a value based on the opening amount and the gap amount satisfies the condition based on the allowable amount and approaches the allowable amount. The control device for an injection molding machine according to Claim 1.

3. The acquisition unit obtains the mold clamping force from the detection result of a detection device provided on a tie bar that extends according to the mold clamping force, The adjustment unit adjusts the mold clamping force of the mold clamping device based on the change amount of the mold clamping force when the molding material is injected into the mold device. The control device for an injection molding machine according to Claim 1 or 2.

4. The acquisition unit obtains the gap amount in response to an input received from an operating device. The control device for an injection molding machine according to Claim 1 or 2.

5. The acquisition unit obtains the allowable amount corresponding to the type of the molding material for which an input has been received. The control device for an injection molding machine according to Claim 1 or 2.

6. An output control unit that outputs at least one of the allowable amount, the opening amount, and a value based on the opening amount and the gap amount to a display device. The control device for an injection molding machine according to Claim 1 or 2, further comprising the above.

7. A processing unit that monitors whether a value based on the opening amount and the gap amount satisfies the condition based on the allowable amount each time the molding material is injected into the mold device closed by the mold clamping device. The control device for an injection molding machine according to Claim 1 or 2, further comprising the above.

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