JP2024073987A - Injection molding machine measuring device, and injection molding machine - Google Patents

Abstract

[Problem] To appropriately recognize the amount of molding material injected. [Solution] A measurement device for an injection molding machine according to one embodiment includes a measurement mechanism having a filling port capable of being filled with molding material injected from an injection device of an injection molding machine, a discharge port capable of discharging the molding material, and a space connecting the filling port and the discharge port, and a control unit configured to calculate the amount of molding material discharged from the discharge port, calculate the amount of molding material remaining in the space, and calculate the amount of molding material injected from the injection device into the filling port in the nth injection (n is a natural number of 2 or more) based on the amount of molding material discharged from the discharge port by the nth injection, the amount of molding material remaining in the space after the nth injection, and the amount of molding material remaining in the space after the n-1th injection. [Selected Figure] Figure 3

Description

The present invention relates to a measuring device for an injection molding machine and an injection molding machine.

Conventionally, in order to measure the amount of molding material filled in an injection molding machine, a technique has been generally used in which the molding material is cooled and solidified in the mold device into which it is filled, and then the molded product produced by cooling and solidifying is measured using a balance or the like. With this technique, it is necessary to wait until the material has cooled and solidified, and it takes time to measure the weight using a balance or the like.

In recent years, technology has been proposed for injection molding machines that measures the amount of molding material (e.g., the weight of the material filled into the mold) before it cools and solidifies (e.g., Patent Document 1).

Japanese Patent Application Laid-Open No. 02-265724

However, Patent Document 1 is a technology for calculating the filling weight of molding material filled in a mold device, not a technology for calculating the amount of molding material injected from an injection device.

One aspect of the present invention provides a technology that provides a mechanism for calculating the amount of molding material injected from an injection unit of an injection molding machine.

A measuring device for an injection molding machine according to one aspect of the present invention includes a measuring mechanism having a filling port capable of being filled with molding material injected from an injection device of an injection molding machine, a discharge port capable of discharging the molding material, and a space connecting the filling port and the discharge port, and a control unit configured to calculate the amount of molding material discharged from the discharge port, calculate the amount of molding material remaining in the space, and calculate the amount of molding material injected from the injection device into the filling port in the nth injection based on the amount of molding material discharged from the discharge port by the nth injection (n is a natural number of 2 or more), the amount of molding material remaining in the space after the nth injection, and the amount of molding material remaining in the space after the n-1th injection.

According to one aspect of the present invention, a technology is provided that can recognize variations in the amount of injected molding material.

FIG. 1 is a diagram showing a state when mold opening of an injection molding machine according to an embodiment is completed. FIG. 2 is a diagram showing a state during mold clamping of the injection molding machine according to the embodiment. FIG. 3 is a diagram illustrating a measurement device of the injection molding machine according to the first embodiment. FIG. 4 is an enlarged view of a first region of FIG. 3 in the measurement mechanism according to the first embodiment. FIG. 5 is an enlarged view of the second region of FIG. 3 in the measurement mechanism according to the first embodiment. FIG. 6 is a diagram showing components of the information processing apparatus according to the first embodiment in the form of functional blocks. FIG. 7 is a diagram showing a change caused by filling the measurement mechanism with molding material by the injection device according to the first embodiment. FIG. 8 is a diagram showing the PVT characteristics of the molding material according to the first embodiment.

The following describes an embodiment of the present invention with reference to the drawings. The embodiments described below are illustrative and do not limit the invention, and all features and combinations described in the embodiments are not necessarily essential to the invention. In addition, identical or corresponding components in each drawing are denoted by identical or corresponding reference numerals, and descriptions thereof may be omitted.

Figure 1 is a diagram showing the state of the injection molding machine according to the first embodiment when mold opening is completed. Figure 2 is a diagram showing the state of the injection molding machine according to the first embodiment when mold clamping is performed. 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 of a horizontal type, the X-axis direction is the mold opening/closing direction, and the Y-axis direction is the width direction of the injection molding machine 10. The negative side of the Y-axis direction is called the operation side, and the positive side of the Y-axis direction is called the anti-operation side.

As shown in Figures 1 and 2, the injection molding machine 10 has a mold clamping device 100 that opens and closes the mold device 800, an ejector device 200 that ejects a molded product molded by the mold device 800, an injection device 300 that injects molding material into the mold device 800, a moving device 400 that moves the injection device 300 forward and backward relative 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 arranged in the internal space of the injection device frame 920. Each component of the injection molding machine 10 will be described below.

(Mold clamping device)
In the description of the mold clamping apparatus 100, the moving direction of the movable platen 120 during mold closing (e.g., the positive X-axis direction) is defined as the front, and the moving direction of the movable platen 120 during mold opening (e.g., the negative X-axis direction) is defined as the rear.

The mold clamping device 100 closes, pressurizes, clamps, depressurizes, and opens the mold device 800. The mold device 800 includes a fixed mold 810 and a movable mold 820. The mold clamping device 100 is, for example, a horizontal type, and the mold opening and closing direction is horizontal. The mold 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 movement mechanism 102 that moves the movable platen 120 in the mold opening and closing direction relative to the fixed platen 110.

The fixed platen 110 is fixed to the mold clamping unit frame 910. The fixed mold 810 is attached to the surface of the fixed platen 110 facing the movable platen 120.

The movable platen 120 is arranged so as to be movable in the mold opening and closing direction relative to the mold clamping unit frame 910. A guide 101 that guides the movable platen 120 is laid on the mold clamping unit frame 910. A movable mold 820 is attached to the surface of the movable platen 120 that faces the fixed platen 110.

The moving mechanism 102 performs mold closing, pressurization, mold clamping, depressurization, and mold opening of the mold device 800 by moving the movable platen 120 forward and backward relative to the fixed platen 110. The moving mechanism 102 has a toggle support 130 arranged at a distance 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 and closing direction relative to the toggle support 130, a mold clamping motor 160 that operates the toggle mechanism 150, a motion conversion mechanism 170 that converts the rotational motion of the mold clamping motor 160 into linear motion, and a mold thickness adjustment mechanism 180 that adjusts the distance between the fixed platen 110 and the toggle support 130.

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

In this embodiment, the fixed platen 110 is fixed to the mold clamping unit frame 910, and the toggle support 130 is arranged to be movable relative to the mold clamping unit frame 910 in the mold opening/closing direction; however, the toggle support 130 may be fixed to the mold clamping unit frame 910, and the fixed platen 110 may be arranged to be movable relative to the mold clamping unit frame 910 in the mold opening/closing direction.

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

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

The toggle mechanism 150 is disposed between the movable platen 120 and the toggle support 130, and moves the movable platen 120 in the mold opening/closing direction relative to the toggle support 130. The toggle mechanism 150 has a crosshead 151 that moves in the mold opening/closing direction, and a pair of link groups that bend and stretch with the movement of the crosshead 151. Each of the pair of link groups has a first link 152 and a second link 153 that are connected to bendable and stretchable by a pin or the like. The first link 152 is attached to the movable platen 120 by a pin or the like so that it can swing freely. The second link 153 is attached to the toggle support 130 by a pin or the like so that it can swing freely. The second link 153 is attached to the crosshead 151 via a third link 154. When the crosshead 151 is advanced or retreated relative to the toggle support 130, the first link 152 and the second link 153 bend and stretch, and the movable platen 120 advances or retreats relative to the toggle support 130.

The configuration of the toggle mechanism 150 is not limited to the configuration shown in Figs. 1 and 2. For example, although the number of nodes in each link group is five in Figs. 1 and 2, it may be four, and one end of the third link 154 may be connected to a node between the first link 152 and the second link 153.

The mold clamping motor 160 is attached to the toggle support 130 and operates the toggle mechanism 150. The mold clamping motor 160 moves the crosshead 151 forward and backward relative to the toggle support 130, thereby bending and extending the first link 152 and the second link 153 and moving the movable platen 120 forward and backward relative to the toggle support 130. The mold clamping motor 160 is directly connected to the motion conversion mechanism 170, but may also be connected to the motion conversion mechanism 170 via a belt, pulley, etc.

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

The mold clamping device 100 performs processes such as mold closing, pressure increase, mold clamping, depressurization, and mold opening under the control of the control device 700.

In the mold closing process, the mold clamping motor 160 is driven to move the crosshead 151 forward at a set movement speed to the mold closing completion position, thereby moving the movable platen 120 forward and touching the movable mold 820 to the fixed mold 810. The position and movement 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.

The crosshead position detector that detects the position of the crosshead 151 and the crosshead movement speed detector that detects the movement speed of the crosshead 151 are not limited to the mold clamping motor encoder 161, and general-purpose detectors can be used. Also, the movable platen position detector that detects the position of the movable platen 120 and the movable platen movement speed detector that detects the movement speed of the movable platen 120 are not limited to the mold clamping motor encoder 161, and general-purpose detectors can be used.

During the pressure increase process, the clamping motor 160 is further driven to move the crosshead 151 further forward from the mold closing completion position to the clamping position, thereby generating a clamping force.

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

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

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

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

The set conditions for the mold closing process, pressure increase process, and mold clamping process are set together as a series of set conditions. For example, the movement speed and position of the crosshead 151 in the mold closing process and pressure increase process (including the mold closing start position, movement speed switching position, mold closing completion position, and mold clamping position) and the mold clamping force are set together as a series of set conditions. The mold closing start position, movement speed switching position, mold closing completion position, and mold clamping position are arranged in this order from the rear side to the front, and represent the start and end points of the section in which the movement speed is set. The movement speed is set for each section. There may be one or more movement speed switching positions. The movement speed switching position does not have to be set. Only one of the mold clamping position and the mold clamping force may be set.

The setting conditions for the depressurization process and mold opening process are also set in a similar manner. For example, the movement speed and position of the crosshead 151 in the depressurization process and mold opening process (mold opening start position, movement speed switching position, and mold opening completion position) are set together as a series of setting conditions. The mold opening start position, movement speed switching position, and mold opening completion position are arranged in this order from the front to the rear, and represent the start and end points of the section in which the movement speed is set. The movement speed is set for each section. There may be one or more movement speed switching positions. The movement speed switching position does not have to be set. The mold opening start position and mold closing completion position may be the same position. Also, the mold opening completion position and mold closing start position may be the same position.

In addition, instead of the moving speed and position of the crosshead 151, the moving speed and position of the movable platen 120 may be set. Also, instead of the position of the crosshead (e.g., the clamping position) or the position of the movable platen, the clamping force may be set.

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 between the first link 152 and the second link 153 (hereinafter also called the "link angle θ"). The link angle θ is determined from the position of the crosshead 151. When the link angle θ is 180°, the toggle ratio is maximum.

When the thickness of the mold device 800 changes due to replacement of the mold device 800 or a temperature change of the mold device 800, the mold thickness is adjusted so that a predetermined clamping force is obtained during mold clamping. In the mold thickness adjustment, for example, the distance L between the fixed platen 110 and the toggle support 130 is adjusted so that the link angle 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.

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

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

The rotational drive force transmission unit 185 is composed of, for example, gears. In this case, a driven gear is formed on the outer periphery of each screw nut 182, a drive gear is attached to the output shaft of the mold thickness adjustment motor 183, and an intermediate gear that meshes with the multiple driven gears and the drive gear is rotatably held in the center of the toggle support 130. Note that the rotational drive force transmission unit 185 may be composed of a belt, pulleys, etc. instead of gears.

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

The distance 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 to monitor and control the position of the toggle support 130 and the distance L. Note that the toggle support position detector that detects the position of the toggle support 130 and the distance detector that detects the distance L are not limited to the mold thickness adjustment motor encoder 184, and general types can be used.

The mold clamping device 100 may have a mold temperature regulator that regulates the temperature of the mold device 800. The mold device 800 has a flow path for a temperature control medium inside. The mold temperature regulator regulates the temperature of the temperature control medium supplied to the flow path of the mold device 800, thereby regulating the temperature of the mold device 800.

In addition, the mold clamping device 100 of this embodiment is a horizontal type in which the mold opening and closing direction is horizontal, but it may also be a vertical type in which the mold opening and closing direction is vertical.

The clamping device 100 of this embodiment has a clamping motor 160 as a drive source, but may have a hydraulic cylinder instead of the clamping motor 160. The clamping device 100 may also have a linear motor for opening and closing the mold, and an electromagnet for clamping the mold.

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

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

The ejector rod 210 is arranged in a through hole of the movable platen 120 so as to be freely 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.

The drive mechanism 220 has, for example, an ejector motor and a motion conversion mechanism that converts the rotational motion of the ejector motor into the linear motion of the ejector rod 210. The motion conversion mechanism includes a screw shaft and a screw nut that screws onto the screw shaft. Balls or rollers may be interposed between the screw shaft and the screw nut.

The ejector unit 200 performs the ejection process under the control of the control unit 700. In the ejection process, the ejector rod 210 advances from the standby position to the ejection position at a set moving speed, thereby advancing the ejector plate 826 and ejecting the molded product. The ejector motor is then driven to move the ejector rod 210 backward at the set moving speed, and the ejector plate 826 backward to the original standby position.

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

(Injection device)
In the explanation of the injection unit 300, unlike the explanations of the mold clamping unit 100 and the ejector unit 200, the movement direction of the screw 330 during filling (e.g., the negative X-axis direction) is described as the front, and the movement direction of the screw 330 during metering (e.g., the positive X-axis direction) is described as the rear.

The injection device 300 is installed on a slide base 301, and the slide base 301 is arranged so as to be freely movable forward and backward with respect to the injection device frame 920. The injection device 300 is arranged so as to be freely movable forward and backward with respect to the mold device 800. The injection device 300 touches the mold device 800 and fills the molding material measured in the cylinder 310 into the cavity space 801 in the mold device 800. The injection device 300 has, 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 arranged so as to be freely 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.

Cylinder 310 heats the molding material supplied to the inside from supply port 311. The molding material includes, for example, resin. The molding material is formed, for example, in pellet form and supplied to supply port 311 in a solid state. Supply port 311 is formed at the rear of cylinder 310. A cooler 312 such as a water-cooled cylinder is provided on the outer periphery of the rear of cylinder 310. A heater 313 such as a band heater and a temperature detector 314 are provided on the outer periphery of cylinder 310 forward of cooler 312.

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

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.

The screw 330 is arranged in the cylinder 310 so that it can rotate freely and move forward and backward. When the screw 330 is rotated, the molding material is sent forward along the spiral groove of the screw 330. As the molding material is sent forward, it is gradually melted by heat from the cylinder 310. As the liquid molding material is sent forward to the front of the screw 330 and accumulates at the front of the cylinder 310, the screw 330 is moved backward. When the screw 330 is then moved forward, the liquid molding material accumulated in front of the screw 330 is injected from the nozzle 320 and filled into the mold device 800.

A backflow prevention ring 331 is attached to the front of the screw 330 so that it can move back and forth as a backflow prevention valve that prevents the molding material from flowing back from the front to the rear of the screw 330 when the screw 330 is pushed forward.

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

Meanwhile, when the screw 330 is rotated, the backflow prevention ring 331 is pushed forward by the pressure of the molding material sent forward along the spiral groove of the screw 330, and advances relative to the screw 330 to an open position (see FIG. 1) where the flow path of the molding material is opened. This causes the molding material to be sent forward of the screw 330.

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.

The injection device 300 may also have a drive source that moves the backflow prevention ring 331 back and forth between the open position and the closed position relative to the screw 330.

The metering motor 340 rotates the screw 330. The driving source that rotates the screw 330 is not limited to the metering motor 340 and may be, for example, a hydraulic pump.

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

The load detector 360 detects the load transmitted between the injection motor 350 and the screw 330. The detected load is converted to 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.

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

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

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

In the metering process, the metering motor 340 is driven to rotate the screw 330 at a set rotational speed, and the molding material is sent forward along the spiral groove of the screw 330. As a result, the molding material is gradually melted. As the liquid molding material is sent forward of the screw 330 and accumulates at the front of the cylinder 310, the screw 330 is moved backward. The rotational speed of the screw 330 is detected, for example, using 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 rotational speed detector that detects the rotational speed of the screw 330 is not limited to the metering motor encoder 341, and a general one can be used.

In the metering process, in order to limit the sudden retreat 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, for example, using a load detector 360. When the screw 330 retreats to the metering completion position and a predetermined amount of molding material is accumulated in front of the screw 330, the metering process is completed.

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

In the filling process, the injection motor 350 is driven to advance the screw 330 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, by 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, a switch from the filling process to the pressure holding process (so-called V/P switch) is performed. The position where the V/P switch is performed is also called the V/P switch position. The set moving speed of the screw 330 may be changed depending on the position of the screw 330, time, etc.

The position and movement speed of the screw 330 in the filling process are set together as a series of setting conditions. For example, a filling start position (also called the "injection start position"), a movement speed switching position, and a 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 for which the movement speed is set. The movement speed is set for each section. There may be one or more movement speed switching positions. The movement speed switching positions do not have to be set.

For each section in which the movement speed of the screw 330 is set, an upper limit value for 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 equal to or lower than the set pressure, the screw 330 is advanced at the set movement speed. On the other hand, when the pressure of the screw 330 exceeds the set pressure, in order to protect the mold, the screw 330 is advanced at a movement speed slower than the set movement speed so that the pressure of the screw 330 is equal to or lower than the set pressure.

In addition, after the position of the screw 330 reaches the V/P switching position during the filling process, the screw 330 may be temporarily stopped at the V/P switching position, and then the V/P switching may be performed. Immediately before the V/P switching, instead of stopping the screw 330, the screw 330 may be moved forward or backward at a slow speed. In addition, the screw position detector that detects the position of the screw 330 and the screw movement speed detector that detects the movement speed of the screw 330 are not limited to the injection motor encoder 351, and general ones can be used.

In the holding pressure process, the injection motor 350 is driven to push the screw 330 forward, and the pressure of the molding material at the front end of the screw 330 (hereinafter also referred to as the "holding pressure") is maintained at a set pressure, and the molding material remaining in the cylinder 310 is pushed toward the mold device 800. The molding material that is insufficient due to cooling contraction in the mold device 800 can be replenished. The holding pressure is detected, for example, using a load detector 360. The set value of the holding pressure may be changed depending on the elapsed time from the start of the holding pressure process. The holding pressure and the holding time for which the holding pressure is maintained in the holding pressure process may each be set multiple times, or may be set together as a series of setting conditions.

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

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

In addition, the injection device 300 of this embodiment is a horizontal type in which the axial direction of the cylinder 310 is horizontal, but it may be a vertical type in which the axial direction of the cylinder 310 is vertical. The mold clamping device combined with the vertical injection device 300 may be either a vertical type or a horizontal type. Similarly, the mold clamping device combined with the horizontal injection device 300 may be either a horizontal type or a vertical type.

(Mobile device)
In describing the moving device 400, similar to the description of the injection device 300, the movement direction of the screw 330 during filling (e.g., the negative X-axis direction) will be described as the forward direction, and the movement direction of the screw 330 during metering (e.g., the positive X-axis direction) will be described as the rearward direction.

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

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, and by switching the rotation direction of the motor 420, it draws in hydraulic fluid (e.g., oil) from either the first port 411 or the second port 412 and discharges it from the other port, generating hydraulic pressure. The hydraulic pump 410 can also draw in hydraulic fluid from a tank and discharge the hydraulic fluid from either the first port 411 or the second port 412.

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

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.

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

Meanwhile, the rear chamber 436 of the hydraulic cylinder 430 is connected to the second port 412 of the hydraulic pump 410 via the second flow path 402. The hydraulic fluid discharged from the second port 412 is supplied to the rear chamber 436 of the hydraulic cylinder 430 via the second flow path 402, thereby pushing the injection device 300 backward. The injection device 300 is retracted, and the nozzle 320 is separated from the fixed mold 810.

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

(Control device)
The control device 700 is composed of, for example, a computer, and has 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 Figures 1 and 2. The control device 700 performs various controls by having the CPU 701 execute a program stored in the storage medium 702. The control device 700 also receives signals from the outside through the input interface 703 and transmits signals to the outside through the output interface 704. The control device 700 also transmits information to an external device through the communication interface 705.

The control device 700 repeatedly produces molded products by repeating processes such as the metering process, mold closing process, pressure increase process, mold clamping process, filling process, pressure holding process, cooling process, depressurization process, mold opening process, and ejection process. A series of operations required to obtain a molded product, for example the operations from the start of a metering process to the start of the next metering process, is also called a "shot" or "molding cycle." The time required for one shot is also called the "molding cycle time" or "cycle time."

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

In order to shorten the molding cycle time, multiple processes may be performed simultaneously. For example, the metering process may be performed during the cooling process of the previous molding cycle, or during the mold clamping process. In this case, the mold closing process may be performed at the beginning of the molding cycle. The filling process may be started during the mold closing process. The ejection process may be started during the mold opening process. If an opening/closing valve is provided to open and close the flow path of the nozzle 320, 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, molding material will not leak from the nozzle 320 as long as the opening/closing valve closes the flow path of the nozzle 320.

Note that one molding cycle may include processes other than the metering process, mold closing process, pressure increase process, mold clamping process, filling process, pressure holding process, cooling process, depressurization process, mold opening process, and ejection process.

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

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

The control device 700 is connected to an operation device 750 that accepts input operations by the user and a display device 760 that displays a screen. The operation device 750 and the display device 760 may be configured, for example, by a touch panel 770 and may be integrated. The touch panel 770 as the display device 760 displays a screen under the control of the control device 700. The screen of the touch panel 770 may display, for example, information such as the settings of the injection molding machine 10 and the current state of the injection molding machine 10. The touch panel 770 allows operations to be accepted in the displayed screen area. In addition, the screen area of the touch panel 770 may display, for example, operation units such as buttons and input fields that accept input operations by the user. 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. As a result, for example, the user can operate the operation unit provided on the screen while checking the information displayed on the screen to perform settings of the injection molding machine 10 (including input of setting values), etc. Furthermore, the user can operate the operation unit provided on the screen to perform the operation of the injection molding machine 10 corresponding to the operation unit. Note that the operation of the injection molding machine 10 may be, for example, the operation (including stopping) of the clamping device 100, the ejector device 200, the injection device 300, the moving device 400, etc. Also, the operation of the injection molding machine 10 may be, for example, switching of the screen displayed on the touch panel 770 as the display device 760.

In the present embodiment, the operation device 750 and the display device 760 are described as being integrated as the touch panel 770, but they may be provided independently. Also, multiple operation devices 750 may be provided. The operation device 750 and the display device 760 are disposed on the operation side (negative Y-axis direction) of the mold clamping unit 100 (more specifically, the fixed platen 110).

First Embodiment
In this embodiment, a measuring device is used to calculate the amount of molding material (weight, in this embodiment, as an example) injected from the injection unit 300 of the injection molding machine 10. In this embodiment, weight is shown as an example of the amount of molding material, but the amount of molding material may be something other than weight.

Figure 3 is a diagram illustrating a measurement device of the injection molding machine 10 according to this embodiment.

The measurement device 1200 is composed of a measurement mechanism 1000 and an information processing device 1100.

In this embodiment, a measurement mechanism 1000 is attached to the injection molding machine 10 in order to calculate the weight of the molding material injected from the injection unit 300. In this embodiment, in order to attach the measurement mechanism 1000, the mold unit 800 attached to the injection molding machine 10 is removed. Then, by attaching the measurement mechanism 1000 to the position where the mold unit 800 is provided, the molding material is injected into the measurement mechanism 1000 instead of the mold unit 800.

In this way, the measurement mechanism 1000 can be installed on the injection molding machine 10, replacing the mold device 800 provided on the injection molding machine 10.

Then, based on the detection results of the various sensors installed in the measuring mechanism 1000, the information processing device 1100 calculates the weight of the injected molding material.

The measurement mechanism 1000 shown in FIG. 3 is fixed to the stationary platen 110 of the injection molding machine 10. Any fixing method may be used, for example, the measurement mechanism 1000 may be fixed to the stationary platen 110 with a bolt. The movable platen 120 may be located anywhere as long as it is not located near the end of the measurement mechanism 1000 in the -X axis direction.

As shown in FIG. 3, the measurement mechanism 1000 has a nozzle storage space 1006 formed on the fixed platen 110 side (+X axis direction side) for arranging the nozzle 320 of the injection device 300.

The nozzle storage space 1006 is provided at its end in the -X axis direction with a filling port 1021 that can be filled with molding material injected from the injection device 300 of the injection molding machine 10. The measurement mechanism 1000 is filled with molding material from the filling port 1021.

In addition, an outlet 1022 capable of discharging the molding material is provided at the end of the measuring mechanism 1000 in the -X axis direction. The molding material is discharged from the outlet 1022 depending on the situation. The circumstances under which the molding material is discharged will be described later.

The measurement mechanism 1000 has a space that connects the fill port 1021 and the discharge port 1022. In this embodiment, the internal space of the measurement mechanism 1000 includes at least the sprue portion 1001, the runner portion 1002, and the cavity portion 1004 to bring it closer to the inside of the mold device 800. For example, the sprue portion 1001, the runner portion 1002, and the cavity portion 1004 are flow paths that connect each portion, and may have a cylindrical shape. The internal configuration of the measurement mechanism 1000 is shown as an example, and is not limited to this configuration.

The sprue portion 1001 is a space having a diameter _D1 and a length _L1 . The length _L1 and the diameter _D1 are determined depending on the embodiment.

The runner portion 1002 is a space having a diameter _D2 and a length _L2 . The length _L2 and the diameter _D2 are determined depending on the embodiment. In this embodiment, the diameter _D2 of the runner portion 1002 is smaller than the diameter _D1 of the sprue portion 1001. Although this embodiment describes an example in which the runner portion 1002 is provided, the embodiment may be one in which the runner portion 1002 is not provided. In the embodiment in which the runner portion 1002 is not provided, for example, the sprue portion 1001 may be directly connected to the gate 1003. Even in this embodiment, the amount of molding material can be calculated.

The cavity portion 1004 is a space having a diameter _D4 and a length _L4 . The length _L4 and the diameter _D4 are determined depending on the embodiment. In this embodiment, the diameter _D4 of the cavity portion 1004 is larger than the diameter _D2 of the runner portion 1002. This embodiment is shown as an example, and for example, the diameter _D4 of the cavity portion 1004 may be smaller than the diameter _D2 of the runner portion 1002.

The lengths _L1 , _L2 , and _L4 may be determined depending on the embodiment, and are preferably several tens of mm or less. For example, the length _L2 may be shorter than the lengths _L1 and _L4 . The diameters _D1 , _D2 , and _D4 may be determined depending on the embodiment, and are preferably several mm or less.

A gate (an example of a restriction) 1003 is provided between the runner portion 1002 and the cavity portion 1004 to suppress the movement of the molding material.

Figure 4 is an enlarged view of the first region 1050A in Figure 3 of the measurement mechanism according to the first embodiment. As shown in Figure 4, the measurement mechanism 1000 has a gate 1003 (an example of a restriction) in a flow path of the molding material connecting the filling port 1021 and the discharge port 1022, the gate 1003 having a narrower opening area than the sprue portion 1001, the runner portion 1002, and the cavity portion 1004 (other regions) present on the flow path. The gate (an example of a restriction) 1003 may have a cylindrical shape.

The gate 1003 is a restriction for suppressing the movement of the molding material. For example, the diameter D3 of the gate ₁₀₀₃ is preferably determined so that the molding material flows when injection pressure is applied for injection from the injection device 300, and resistance is generated to suppress the flow of the molding material when pressure other than injection (e.g. back pressure) is applied.

For example, when the viscosity of the molding material is 2 to 20 (Pa·S), the diameter _D3 of the gate 1003 is 0.2 to 0.5 (mm). The length _L3 of the gate 1003 may be shorter than the length _L4 of the cavity portion 1004 and the length _L2 of the runner portion 1002, and is preferably, for example, 0.5 to 1 (mm).

In addition, the outlet 1022 is provided with a constriction to suppress drooling.

Figure 5 is an enlarged view of the second region 1050B in Figure 3 of the measurement mechanism according to the first embodiment. As shown in Figure 5, a throttling portion 1005 is provided between the outlet 1022 and the cavity portion 1004. The throttling portion 1005 may have a cylindrical shape.

The discharge port 1022 discharges the molding material when it is being injected from the injection device 300, but drooling (leakage of molding material) may occur in other situations as well.

Therefore, in this embodiment, the constricted portion 1005 is provided to suppress drooling of the molding material. The diameter _D5 of the constricted portion 1005 is made smaller than at least the diameter _D4 of the cavity portion 1004. That is, in this embodiment, by making the diameter _D5 of the constricted portion 1005 smaller than the diameter _D4 of the cavity portion 1004, resistance to the movement of the molding material exists, and therefore the flow of the molding material is suppressed.

For example, when the viscosity of the molding material is 2 to 20 (Pa·S), the diameter _D5 of the narrowed portion 1005 is 0.5 to 3 (mm). The length _L5 of the narrowed portion 1005 may be determined according to the embodiment.

In this embodiment, the molding material injected from the injection device 300 is, for example, a resin. In this embodiment, the molding material in a molten state is injected from the injection device 300 through the injection port 1021.

The measuring mechanism 1000 according to this embodiment is provided with a heater 1051. The heater (an example of a heating unit) 1051 is, for example, a band heater. The heater 1051 heats the measuring mechanism 1000 from the surroundings, so that the molding material injected into the measuring mechanism 1000 is maintained in a molten state.

Therefore, in this embodiment, the sprue portion 1001, the runner portion 1002, the gate 1003, the cavity portion 1004, and the constriction portion 1005 are filled with the molten molding material discharged from the nozzle 320, and the molten state of the molding material is then maintained.

The measuring mechanism 1000 is also provided with a sensor for measuring the molding material. In this embodiment, a gate 1003 is provided to suppress the movement of the molding material. In other words, the condition of the molding material (e.g., pressure and temperature) changes through the gate 1003. Therefore, in this embodiment, a sensor 1011 is provided in the sprue portion 1001 before the molding material passes through the gate, and a sensor 1012 is provided in the cavity portion 1004 after the molding material passes through the gate.

The sensor 1011 is a sensor for detecting the state of the molding material present in the sprue portion 1001. The sensor 1011 includes a pressure sensor and a temperature sensor. It is sufficient if the state of the molding material (e.g., clay) can be detected, but in consideration of the cost, size, and the impact on the layout due to ease of routing, a pressure sensor and a temperature sensor are preferable.

For example, a pressure sensor such as sensor 1011 detects the pressure of the molding material inside the sprue portion 1001 adjacent to the sensor 1011.

The temperature sensor 1011 detects the temperature of the molding material inside the sprue portion 1001 adjacent to the sensor 1011.

The sensor 1012 is a sensor for detecting the state of the molding material present in the cavity portion 1004. The sensor 1012 includes at least a pressure sensor and a temperature sensor.

For example, a pressure sensor as sensor 1012 detects the pressure of the molding material inside the cavity portion 1004 adjacent to the sensor 1012.

The temperature sensor 1012 detects the temperature of the molding material inside the cavity portion 1004 adjacent to the sensor 1012.

The sensors 1011 and 1012 in this embodiment constantly measure the state of the molding material.

Furthermore, in this embodiment, the detection result of the molding material by the sensor 1011 is applied to the molding material present in the sprue section 1001 and the runner section 1002. In other words, before passing through the gate 1003, it is assumed that there is no change in the pressure and temperature of the molding material, and the detection result of the molding material by the sensor 1011 is applied not only to the sprue section 1001 but also to the runner section 1002.

Note that this embodiment shows an example of a sensor installation mode, and sensors may be installed in both the sprue section 1001 and the runner section 1002.

In this embodiment, a sensor 1013 is further provided. The sensor 1013 detects the temperature near the outer periphery of the measuring mechanism 1000 and outputs the detection result to the information processing device 1100. The information processing device 1100 then controls the temperature of the heater 1051 so that the molding material in the measuring mechanism 1000 can be maintained in a molten state.

Next, an information processing device 1100 will be described that uses the detection results of sensors 1011 and 1012 to measure the weight of the molding material injected from the injection device 300 as the injection amount. In this embodiment, the number of injections from the injection device 300 is counted as the number of shots. This embodiment describes an example of measuring the weight as the injection amount of the injected molding material. Note that this embodiment shows weight as an example of the injection amount, and does not limit the injection amount to weight.

FIG. 6 is a functional block diagram showing components of an information processing device 1100 according to the first embodiment. The information processing device 1100 is configured, for example, by a computer, and has a CPU (Central Processing Unit) 1101 and a storage medium 1102. The information processing device 1100 performs various controls by causing the CPU 1101 to execute a program stored in the storage medium 1102.

The functional blocks shown in FIG. 6 are conceptual, and do 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. All or any part of the processing functions performed by each functional block are realized by a program executed by the CPU 1101. Alternatively, each functional block may be realized as hardware using wired logic. As shown in FIG. 6, the CPU 1101 includes an acquisition unit 1111, an emission amount calculation unit 1112, a residual amount calculation unit 1113, an injection amount calculation unit 1114, and a write control unit 1115. The control device 700 also includes a log information storage unit 1121 in the storage medium 1102.

The log information storage unit 1121 stores log information related to the amount of molding material injected from the injection device 300 into the filling port 1021. The log information is, for example, information related to the weight of the molding material injected each time injection is performed.

In this embodiment, the information processing device 1100 calculates the injection amount of the injected molding material, taking into account the movement of the molding material within the measurement mechanism 1000. Here, the relationship between the movement of the molding material within the measurement mechanism 1000 in this embodiment and the injection of the molding material into the measurement mechanism 1000 will be described.

Figure 7 shows the changes caused by the injection of molding material into the measurement mechanism 1000 by the injection device 300 according to this embodiment.

Situation 1701 in FIG. 7 shows the completion of dwelling for the n-1th shot (an n-1th example). In situation 1701, due to the injection up to the n-1th shot, molten molding material remains in the space within the measurement mechanism 1000 (spur section 1001, runner section 1002, gate 1003, cavity section 1004, and constriction section 1005). In this embodiment, the amount (e.g., weight) of molding material in the space within the measurement mechanism 1000 at the completion of dwelling for the n-1th shot is defined as the amount of molding material remaining in the n-1th shot. Note that n is a natural number of 2 or more.

Situation 1702 in FIG. 7 shows the nth shot (an example of the nth injection). In situation 1702, the liquid molding material accumulated in front of the screw 330 is injected from the nozzle 320 into the measurement mechanism 1000 by the nth shot injection. As the molding material is injected into the measurement mechanism 1000, the molding material is discharged from the discharge port 1022 as shown by the arrow 1721. In this embodiment, the amount (e.g., weight) of the molding material injected from the injection device 300 into the filling port 1021 of the measurement mechanism 1000 during the nth shot injection is defined as the injection amount of the molding material for the nth shot. In this embodiment, the amount (e.g., weight) of the molding material discharged from the discharge port 1022 of the measurement mechanism 1000 during the nth shot injection is defined as the discharge amount of the molding material for the nth shot.

Situation 1703 in FIG. 7 shows the completion of dwelling for the nth shot (nth example). In situation 1703, the injection up to the nth shot results in molten molding material being injected into the space within the measurement mechanism 1000 (spur section 1001, runner section 1002, gate 1003, cavity section 1004, and constriction section 1005). In this embodiment, the amount (e.g., weight) of molding material in the space within the measurement mechanism 1000 at the completion of dwelling for the nth shot is defined as the remaining amount of molding material for the nth shot.

The difference between the weight of the molding material injected from the nozzle 320 in the nth shot and the weight of the molding material discharged from the discharge port 1022 in the nth shot is the difference in weight of the molding material remaining in the measurement mechanism 1000 after completion of the dwelling pressure between the n-1th shot and the nth shot. In other words, "injection amount of molding material in the nth shot - discharge amount of molding material in the nth shot = remaining amount of molding material after the nth shot - remaining amount of molding material after the 'n-1'th shot" is established. Therefore, the injection amount of the molding material in the nth shot can be calculated by the following formula _{(1). Note that (injection amount) n is the weight of the molding material injected in the nth shot, (discharge amount) n is the weight of the molding material discharged in the nth shot, (residual amount) n-1 is the} weight of the molding material remaining after the n-1th shot, and (residual amount) _n is the weight of the molding material remaining after the nth shot.

Therefore, the information processing device 1100 according to this embodiment calculates the injection amount (e.g., weight) of the molding material injected in the nth shot based on the above-mentioned formula (1).

The acquisition unit 1111 acquires detection results from various sensors. For example, the acquisition unit 1111 acquires the detection results of the sensors 1011 and 1012. Specifically, the acquisition unit 1111 acquires the temperature and pressure of the molding material remaining in the sprue portion 1001 from the sensor (an example of a detection unit) 1011. The acquisition unit 1111 acquires the temperature and pressure of the molding material remaining in the cavity portion 1004 from the sensor (an example of a detection unit) 1012.

The residual amount calculation unit 1113 calculates the amount of molding material remaining in the space within the measurement mechanism 1000 (the sprue portion 1001, the runner portion 1002, the gate 1003, the cavity portion 1004, and the constriction portion 1005).

The residual amount calculation unit 1113 according to this embodiment calculates (residual amount) _n-1 , which indicates the weight of molding material remaining in the measurement mechanism 1000 after the n-1th shot, and (residual amount) _n , which indicates the weight of molding material remaining in the measurement mechanism 1000 after the nth shot, as calculated by formula (1). (Residual amount) _n is calculated using the following formula (2). _{ρ n cavity} is the density of molding material remaining in the cavity portion 1004 after the nth shot. _{ρ n sprue} is the density of molding material remaining in the sprue portion 1001 after the nth shot. _{V cavity} is the volume of the cavity portion 1004. V _choke is the volume of the choke portion 1005. _{V sprue} is the volume of the sprue portion 1001. V _runner is the volume of the runner portion 1002. V _gate is the volume of the gate 1003.

The pressure and temperature of the molding material in the runner portion 1002 and gate 1003 are considered to be the same as the pressure and temperature in the sprue portion 1001, and the pressure and temperature of the molding material in the constriction portion 1005 are considered to be the same as the pressure and temperature in the cavity portion 1004. This is because even if there is an error in the pressure and temperature, the volume of the V _runner , V _{gate, and} V _constriction is smaller than the volume of the V _sprue and V _cavity , and it is considered that there will be almost no effect on the calculation result. If the length _L2 and diameter _D2 of the runner portion 1002 are not smaller than either or both of the length _L4 and diameter _D4 of the cavity portion 1004 and the length _L1 and diameter _D1 of the sprue portion 1001, a sensor may be provided to detect the temperature and pressure of the molding material in the runner portion 1002.

As shown in formula (2), the density ρ _{n cavity} is expressed as ρ (P _{n cavity} , T _{n cavity} ). ρ (P _{n cavity} , T _{n cavity} ) indicates a calculation method for calculating the density ρ _{n cavity} based on the pressure P _{n cavity} and the temperature T _{n cavity} . The pressure P _{n cavity} indicates the pressure of the molding material remaining in the cavity portion 1004 after the nth shot, and the temperature T _{n cavity} indicates the temperature of the molding material remaining in the cavity portion 1004 after the nth shot.

Next, the PVT characteristics of the molding material will be described. Fig. 8 is a diagram showing the PVT characteristics of the molding material according to this embodiment. As shown in Fig. 8, the vertical axis indicates the specific volume ( ^cm3 /g), and the horizontal axis indicates the temperature (°C). Each line shown in Fig. 8 indicates the correspondence relationship between the volume ( ^cm3 /g) and the temperature (°C) for each pressure. The pressures shown by each line are pressure P1 < pressure P2 < pressure P3 < pressure P4 < pressure P5 < pressure P6 (MPa).

As shown in FIG. 8, the specific volume (cm ³ /g) of the molding material can be specified from the pressure and temperature of the molding material. The specific volume (cm ³ /g) is the reciprocal of the density. That is, as shown by ρ(P _{n cavity} , T _{n cavity} ), the density ρ _{n cavity} of the molding material can be calculated based on the pressure P _{n cavity} and the temperature T _{n cavity .} The pressure P _n cavity and the temperature T n cavity of the molding material of the cavity portion 1004 can be acquired from the sensor 1012. Therefore, the residual amount calculation unit 1113 calculates the density ρ _{n cavity} of the molding material based on the pressure P _{n cavity} and the temperature T _{n cavity} of the cavity portion 1004. A specific calculation method of the density ρ _{n cavity} of the cavity portion 1004 may be calculated based on table information showing a correspondence relationship such as the PVT diagram shown in FIG. 8, or may be calculated by substituting the pressure P _{n cavity} and the temperature T _{n cavity} into a predetermined function.

Also, as shown in formula (2), the density ρ _{n sprue} can be expressed as ρ (P _{n sprue} , T _{n sprue} ). ρ (P _{n sprue} , T _{n sprue} ) indicates a calculation method for calculating the density ρ _{n sprue} based on the pressure P _{n sprue} and the temperature T _{n sprue} . The pressure P _{n sprue} indicates the pressure of the molding material remaining in the sprue part 1001 after the nth shot, and the temperature T _{n sprue} indicates the temperature of the molding material remaining in the sprue part 1001 after the nth shot. The pressure P _{n sprue} and the temperature T _{n sprue} of the molding material in the sprue part 1001 can be acquired from the sensor 1011. Therefore, the residual amount calculation unit 1113 calculates the density ρ _{n sprue} of the molding material in the sprue part 1001 based on the pressure P _{n sprue} and the temperature T _n sprue of the molding material in the sprue part 1001. A specific method for calculating the density ρ _{n sprue} of the sprue portion 1001 may be to calculate based on table information showing a correspondence relationship such as the PVT diagram shown in FIG. 8, or to calculate by substituting the pressure P _{n sprue} and the temperature T _{n sprue} into a predetermined function.

The V _cavity , V _throttle , V _sprue , V _runner , and V _gate can be calculated from various dimensions of the measurement mechanism 1000. For example, the sprue portion 1001, the runner portion 1002, the gate 1003, the cavity portion 1004, and the throttle portion 1005 may be flow paths connecting each portion as described above, and may have a cylindrical shape. In this case, the volumes V _sprue , V runner, V _gate , V cavity, and V _throttle can be derived from the diameters and lengths of the runner portion 1002, the gate 1003, _the cavity portion 1004, and the throttle portion 1005. In this way, the volumes V _sprue , V _runner , V _gate , V _{cavity , and} V _throttle are constants.

Therefore, the residual amount calculation unit 1113 can calculate (residual amount) n, which indicates the residual weight of the molding material after the nth shot, by substituting the pressure and temperature obtained from the sensor 1012 after the nth shot, and the pressure and temperature obtained from the sensor 1011 after the nth shot, into equation ( ₂ ).

Similarly, the residual amount calculation unit 1113 can calculate (residual amount) n-1, which indicates the residual weight of the molding material after the n-1th shot, by substituting the pressure and temperature obtained from sensor 1012 after the n-1th shot, and the pressure and temperature obtained from sensor 1011 after the n _- 1th shot, into equation (2).

In other words, the residual amount calculation unit 1113 can calculate the weight of the molding material remaining in the space based on the volume of the space in the measurement mechanism 1000 and the pressure and temperature of the molding material remaining in the space using the above-mentioned formula (2). The molding material is maintained in a molten state by heating the measurement mechanism 1000 using the heater 1051. Therefore, the residual amount calculation unit 1113 can calculate the weight of the molding material in a molten state.

The discharge amount calculation unit 1112 calculates the amount of molding material discharged from the discharge outlet 1022.

The discharge amount calculation unit 1112 according to the present embodiment calculates the (discharge amount) _n , which indicates the weight of the molding material discharged from the discharge port 1022 in the nth shot, as expressed by formula (1). The (discharge amount) _n is calculated using the following formula (3).

As described above, ρ(P _{n cavity} , T _{n cavity} ) is the density of the molding material in the cavity portion 1004. Q(P _{n cavity} , T _{n cavity} ) indicates the flow rate of the molding material per unit time. Then, in order to calculate the weight of the molding material discharged in the nth shot, the integration of equation (3) is performed from the start of filling to the completion of pressure holding. In this embodiment, the temperature and pressure of the molding material detected by the sensor 1012 are used for each unit time that the sensor 1012 performs detection from the start of filling to the completion of pressure holding.

Q (P _{n cavity} , T _{n cavity} ) can be calculated by using the Hagen-Poiseuille equation. The pressure P _{n cavity} and the temperature T _{n cavity} are detected by the sensor 1012. In this embodiment, in order to calculate the flow rate of the molding material discharged from the discharge port 1022, the length of the flow path from the sensor 1012 to the discharge port 1022, the diameter D ₅ of the constricted portion 1005, and the diameter D ₄ of the cavity portion 1004 are used. The length of the flow path from the sensor 1012 to the discharge port 1022 includes the length L ₄₁ from the sensor 1012 to the constricted portion 1005 and the length L ₅ of the constricted portion 1005. By considering these variables, the formula (4) can be derived. The viscosity η (T _{n cavity} ) of the molding material remaining in the cavity portion 1004 shown in the formula (4) is set. The pressure P _{atmospheric pressure} is the pressure outside the discharge port 1022, in other words, the atmospheric pressure. Any method may be used to detect the atmospheric pressure. In the example shown in formula (4), the shape of the cavity portion 1004 and the narrowed portion 1005 is cylindrical, and the side surface of the cylinder serves as an inner wall for guiding the molding material to the discharge port 1022.

The viscosity η (T _{n cavity} ) can be calculated using the exponential function shown in the following formula (5). As shown in formula (5), the variables B and η ₀ are constants specific to the molding material. R is the gas constant.

Therefore, the discharge amount calculation unit 1112 according to this embodiment can calculate the flow rate Q of the molding material. In addition, the following formula (6) can be calculated from formulas (3) and (4). The temperature T _{n cavity} and the pressure P _{n cavity} are the temperature and pressure of the molding material detected by the sensor 1012 from the start of filling to the end of pressure holding in the nth shot. Therefore, the discharge amount calculation unit 1112 calculates the (discharge amount) _n by applying the temperature T _{n cavity} and the pressure P _{n cavity} of the molding material in the cavity portion 1004 measured by the sensor 1012 per unit time to formula (6).

Therefore, the discharge amount calculation unit 1112 can calculate the weight of the molding material discharged from the discharge port 1022 by the nth injection based on the pressure and temperature of the molding material acquired from the sensors 1011, 1012 (an example of a detection unit) while the injection device 300 is injecting the molding material into the filling port 1021. The molding material is kept in a molten state by heating the measurement mechanism 1000 using the heater 1051. Therefore, the discharge amount calculation unit 1112 can calculate the weight of the molding material in a molten state.

The injection amount calculation unit 1114 calculates the weight of molding material injected from the injection device 300 into the filling port 1021 in the nth injection based on the weight of molding material discharged from the discharge port 1022 in the nth injection (n is a natural number equal to or greater than 2), the weight of molding material remaining in the space within the measurement mechanism 1000 after the nth injection, and the weight of molding material remaining in the space after the n-1th injection.

The injection amount calculation unit 1114 can calculate the (injection amount) _{n by substituting the (residual amount)n} and (residual amount) _n-1 calculated by the residual amount calculation unit 1113 and _{the (discharge amount)n calculated} by the discharge amount calculation unit 1112 into formula (1). Therefore, the weight of the molding material injected from the injection unit 300 in the nth shot is calculated.

Incidentally, by substituting the (residual amount) _n and (residual amount) _n-1 calculated from equation (2) and the (discharge amount) _n calculated from equation (6) into equation (1), the following equation (7) can be derived.

The injection amount calculation unit 1114 may therefore apply the pressure and temperature of the molding material obtained from the sensors 1011 and 1012 (an example of a detection unit) to equation (7) to calculate the weight of the molding material injected from the injection device 300 in the nth shot.

The write control unit 1115 registers and updates the log information stored in the log information storage unit 1121. For example, the write control unit 1115 registers the weight of the molding material injected from the injection device 300 in the nth shot, calculated by the injection amount calculation unit 1114, in the log information stored in the log information storage unit 1121, in association with the injection conditions, etc.

The information processing device 1100 according to this embodiment can calculate the weight of the molding material injected from the injection device 300 for each shot by the above-mentioned control. The calculated weight of the molding material is then registered as log information in the log information storage unit 1121. Therefore, the user can recognize the variation in the weight of the injected molding material (an example of the amount of the injected molding material) by referring to the log information.

In the above-described embodiment, the internal structure of the measurement mechanism 1000 is shown as an example, and is not limited to this structure. In this embodiment, an example is described in which the inside of the measurement mechanism 1000 has a sprue portion 1001, a runner portion 1002, a gate 1003, a cavity portion 1004, and a throttling portion 1005, but the structure is not limited to this. In other words, any structure that can calculate the weight of the molding material remaining in the measurement mechanism 1000 will suffice.

In this embodiment, an example is described in which a gate 1003 is provided to prevent molding material from being discharged from the outlet 1022 at times other than injection, but the present invention is not limited to the method of providing a gate 1003, and instead of the gate 1003, another mechanism may be provided to prevent molding material from being discharged from the outlet 1022 at times other than injection.

In this embodiment, an example has been described in which a heater 1051 is provided to maintain the molten state of the molding material in the measurement mechanism 1000, but the method is not limited to providing a heater 1051, and other mechanisms or methods may be used to maintain the molten state of the molding material. Furthermore, in this embodiment, as long as the sensors 1011 and 1012 can appropriately detect the temperature and pressure of the molding material, it is not necessary to use a method of maintaining the molten state of the molding material.

In this embodiment, a method for calculating the weight of the molding material based on the detected pressure and temperature of the molding material has been described. However, this embodiment is not limited to a method for calculating the weight of the molding material based on the detected pressure and temperature of the molding material, and other methods may be used to calculate the weight of the remaining molding material and the weight of the discharged molding material.

<Action>
In the above-described embodiment, by providing the above-described configuration, the weight of the molding material injected from the injection device 300 by the n-th injection shot can be calculated based on the pressure and temperature of the molding material acquired from the sensors 1011 and 1012 (an example of a detection unit) each time injection is performed from the injection device 300. Therefore, the weight of the molding material injected into the measurement mechanism 1000 for each shot of the injection molding machine can be calculated. Since it is not necessary to wait until the molded product cools and solidifies as in the conventional method, the time until the weight is measured each time injection is performed can be shortened.

In this embodiment, the measurement mechanism 1000 is used, and the weight of the molding material injected from the injection device 300 by the nth injection shot can be calculated based on the pressure and temperature of the molding material obtained from sensors 1011 and 1012 (an example of a detection unit). This makes it possible to calculate the weight of the molding material injected from the injection device 300 to the measurement mechanism 1000 without being limited by the capacity of the mold device 800. In this way, the measurement device 1200 can properly recognize the amount of molding material injected from the injection device 300.

Furthermore, by performing multiple injections, the measuring device 1200 can recognize the variation in the weight of the injected molding material depending on the injection conditions. The variation in weight can be measured for each condition set in the injection molding machine 10. Therefore, the measuring device 1200 according to this embodiment can recognize the variation in the weight of the injected molding material depending on the injection conditions. Therefore, by referring to the log information recorded in the above-mentioned embodiment, it is possible to derive injection conditions that can suppress the variation, thereby improving the stability during injection.

In addition, in this embodiment, the measuring device 1200 can calculate the weight of the molding material after it has been injected from the injection device 300. In other words, the weight of the molding material after it has actually been injected is calculated, rather than estimating the weight of the injected molding material based on the detection results of the state of the molding material inside the cylinder 310 of the injection device 300. Therefore, because the weight of the molding material that has actually been injected is calculated, it is possible to achieve improved weight calculation accuracy compared to estimating the weight of the injected molding material based on the detection results of the state inside the cylinder 310.

Furthermore, in the above-described embodiment, the heater 1051 heats the periphery of the measurement mechanism 1000, so that the molten state of the molding material in the measurement mechanism 1000 can be maintained. Therefore, when the mold device 800 is used, cooling and solidifying of the molding material inside the mold device 800 can be suppressed. In other words, cooling and solidifying of the molding material near the wall surfaces of the sensors 1011 and 1012 can be suppressed. Therefore, it is possible to suppress the occurrence of a situation in which the temperature and pressure of the molten molding material cannot be measured due to the generation of cooled and solidified molding material near the sensors 1011 and 1012. In other words, in the above-described embodiment, since the temperature and pressure of the molten molding material can be detected, it is possible to suppress a decrease in the calculation accuracy of the weight of the molding material actually injected.

The above describes the embodiments of the measurement device for an injection molding machine and the injection molding machine according to the present invention, but the present invention is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. Naturally, these also fall within the technical scope of the present invention.

REFERENCE SIGNS LIST 10 Injection molding machine 300 Injection device 310 Cylinder 320 Nozzle 1200 Measurement device 1000 Measurement mechanism 1001 Sprue portion 1002 Runner portion 1003 Gate 1004 Cavity portion 1005 Constriction portion 1006 Nozzle storage space 1011, 1012 Sensor 1021 Filling port 1022 Discharge port 1051 Heater 1100 Information processing device 1101 CPU
1111 Acquisition unit 1112 Discharge amount calculation unit 1113 Residual amount calculation unit 1114 Injection amount calculation unit 1115 Write control unit 1102 Storage medium 1121 Log information storage unit

Claims (6)

a measuring mechanism having a filling port capable of filling with a molding material injected from an injection unit of an injection molding machine, a discharge port capable of discharging the molding material, and a space connecting the filling port and the discharge port;
Calculating the amount of the molding material discharged from the discharge port;
Calculating the amount of the molding material remaining in the space;
a control unit configured to calculate the amount of the molding material injected from the injection device to the filling port in the nth injection based on the amount of the molding material discharged from the discharge port in the nth injection (n is a natural number equal to or greater than 2), the amount of the molding material remaining in the space after the nth injection, and the amount of the molding material remaining in the space after the n-1th injection;
A measurement device for an injection molding machine comprising: The control unit is
acquiring a pressure and a temperature of the molding material remaining in the space from a detection unit;
Calculating the amount of the molding material remaining in the space based on the volume of the space, the pressure, and the temperature;
while the injection device is injecting the molding material into the filling port, an amount of the molding material discharged from the discharge port by the n-th injection is calculated based on the pressure and the temperature of the molding material acquired from the detection unit.
The measurement device for an injection molding machine according to claim 1. A heating unit that heats the measurement mechanism is further provided.
The control unit is
Calculating the amount of the molding material that has been heated by the heating unit and is in a molten state based on the volume of the space, the pressure, and the temperature;
and calculating, based on the pressure and the temperature acquired from the detection unit while the injection device is injecting the molding material into the filling port, the amount of the molding material discharged from the discharge port and in a molten state due to heating by the heating unit.
The measurement device for an injection molding machine according to claim 2. The measurement mechanism includes a flow path of the molding material that connects the filling port and the discharge port in the space, and a throttle is provided in the flow path, the throttle having an opening area narrower than other areas of the flow path;
The control unit is configured to acquire the temperature and the pressure of the molding material before passing through the orifice, and to acquire the temperature and the pressure of the molding material after passing through the orifice.
The measurement device for an injection molding machine according to claim 2 or 3. The measurement mechanism can be installed in the injection molding machine by replacing a mold device provided in the injection molding machine.
4. The measurement device for an injection molding machine according to claim 1. An injection molding machine equipped with the measuring device according to any one of claims 1 to 3.

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