JP2024066919A - Control device of injection molding machine and display device of injection molding machine - Google Patents

Abstract

To reduce occurrence of a defective product by monitoring gas burns of a molded product.SOLUTION: There is provided a control device of an injection molding machine, comprising: an acquisition unit configured to acquire information indicating a pressure obtained from a detection unit provided near an end portion where a molding material filled in a cavity space is arrived in the cavity space inside a mold device of an injection molding machine; and a control unit configured to determine whether gas burn occurs in a molded product produced by the injection molding machine, or to predict or display a period until gas burn occurs in the molded product based on a predetermined pressure-related condition detected near a time of switching from a filling process to a pressure holding process in the injection molding machine, or near a time when the molding material is filled to the end portion.SELECTED DRAWING: Figure 3

Description

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

Conventionally, there have been technologies for monitoring the state of the molding material during the injection process. For example, the technology described in Patent Document 1 detects the filling pressure and controls the screw rotation speed according to the rate of change of the pressure. This allows injection molding to be performed under conditions where the flow resistance of the molding material is appropriate.

In an injection molding machine, a molded product is produced by pouring molding material into a cavity space inside a mold device. The cavity space is formed at the parting surface between the fixed mold and the movable mold. When the molding material flows into the cavity space, gas present in the cavity space escapes to the outside through the parting surface. This allows the cavity space to be filled with molding material. When injection molding is performed repeatedly, components of the molding material accumulate on the parting surface, making it difficult for the gas to be discharged to the outside of the cavity space. In this case, the gas that is not discharged becomes hot due to adiabatic compression, and there is a possibility that gas burns will occur in the molded product.

Japanese Patent Application Laid-Open No. 03-030926

However, Patent Document 1 only describes a technology for controlling the screw rotation speed according to the detected filling pressure, and does not provide a technology for monitoring gas burns that occur in molded products due to repeated injection molding.

One aspect of the present invention provides a technology that reduces the occurrence of defective products by monitoring gas burns in molded products.

The control device for an injection molding machine according to one aspect of the present invention includes an acquisition unit configured to acquire information indicating pressure from a detection unit provided in a cavity space in a mold device of the injection molding machine near the end where the molding material filled in the cavity space reaches, and a control unit configured to determine whether gas burns have occurred in a molded product produced by the injection molding machine, or to predict or display the period until gas burns occur in the molded product, based on a predetermined condition related to pressure detected near the timing of switching from the filling process to the pressure holding process in the injection molding machine or near the timing when the molding material is filled up to the end.

According to one aspect of the present invention, by monitoring gas burns in molded products, the occurrence of defective products is reduced.

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 functional block diagram showing components of the control device for the injection molding machine according to the first embodiment. FIG. 4 is a diagram showing molding material flowing into the mold device according to the first embodiment and a sensor provided inside the mold device. FIG. 5 is a diagram showing a change in the flow of a molding material with respect to the mold device according to the first embodiment. FIG. 6 is a diagram showing changes in temperature and pressure from the start of filling to pressure dwell in the mold apparatus according to the first embodiment. FIG. 7 is a diagram illustrating an example of a change in pressure detected by a sensor when the mold assembly according to the first embodiment is in a packed state. FIG. 8 is a diagram illustrating an example of a change in pressure detected by a sensor when V/P is switched in the mold device according to the first embodiment. FIG. 9 is a diagram illustrating a log information screen output by the display control unit according to the first embodiment. FIG. 10 is a flowchart showing a process for detecting gas burns in the injection molding machine according to the first embodiment. FIG. 11 is a diagram illustrating a gas burn prediction information screen output by the display control unit according to the second embodiment. FIG. 12 is a flowchart showing a processing procedure up to outputting an alarm in the control device according to the second 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, the tie bar strain detector 141 is used as the clamping force detector that detects 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 configured, for example, by 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 causing the CPU 701 to execute a program stored in the storage medium 702. The control device 700 also receives signals from the outside via the input interface 703, and transmits signals to the outside via the output interface 704.

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.

Note that, 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 that opens and closes the flow path of the nozzle 320 is provided, the mold opening process may be started during the metering process. This is because even if the mold opening process is started during the metering process, 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
FIG. 3 is a diagram showing components of the control device 700 of the injection molding machine 10 according to an embodiment in the form of functional blocks. Each functional block shown in FIG. 3 is conceptual, and does not necessarily have to be physically configured as shown in the figure. All or a part of each functional block can be functionally or physically distributed and integrated in any unit. All or any part of each processing function performed by each functional block is realized by a program executed by the CPU 701. Alternatively, each functional block may be realized as hardware using wired logic. As shown in FIG. 3, the CPU 701 of the control device 700 includes a setting unit 711, an acquisition unit 712, a determination unit 713, a log control unit 714, and a display control unit 715. The control device 700 also includes a log storage unit 721 in the storage medium 702.

The log storage unit 721 stores log information related to the injection molding machine 10. The log information is, for example, information related to the settings and performance of the injection molding each time injection molding is performed by the injection molding machine 10. Specific log information will be described later.

Next, we will explain the method used by the control device 700 in this embodiment to monitor gas burns.

Figure 4 shows the molding material M flowing into the mold device 800 according to this embodiment, and a sensor 841 provided inside the mold device 800.

The molding material M shown in FIG. 4 is, for example, a resin. The molding material M flows into a cavity space 801 inside the mold device 800. The cavity space 801 is formed at a parting surface 830 between the fixed mold 810 and the movable mold 820. The parting surface 830 is generally called a parting line.

When the molding material M flows into the cavity space 801, the gas in the cavity space 801 escapes to the outside of the mold device 800 through the parting surface 830, etc., as shown by the arrows, so that the entire cavity space 801 is filled with the molding material M.

The sensor (an example of a detection unit) 841 is provided in the cavity space 801 in the mold device 800 of the injection molding machine 10, near the end of the flow path represented by the cavity space 801. In other words, the end of the flow path means the end where the molding material filled into the cavity space 801 ends up. In this embodiment, the sensor 841 only needs to be located near the end of the flow path, and does not have to be the final filling section. In other words, the sensor 841 only needs to be able to detect the state of the end of the flow path of the mold device 800.

The sensor 841 detects at least the pressure inside the mold device 800. Furthermore, the sensor 841 detects at least one of the temperature inside the mold device 800 and the distance to the front end (flow front) of the flowing molding material M. In this way, the sensor 841 includes, for example, a pressure sensor. The sensor 841 may be only a pressure sensor, or may further include at least one of a temperature sensor and a distance sensor (for example, a laser sensor). Then, from the detection result of the sensor 841, at least one of the gas condition inside the cavity space 801 and the flow condition of the molding material M inside the cavity space 801 can be estimated.

The pressure sensor as sensor 841 detects the pressure of the gas or molding material M adjacent to the sensor 841.

The temperature sensor 841 detects the temperature of the gas or molding material M adjacent to the sensor 841.

The distance sensor serving as sensor 841 detects the distance to the end of the flow front of the molding material M based on the position of the sensor 841.

Figure 5 shows the change in the flow of molding material M in the mold device 800 according to this embodiment. In the situation shown in Figure 5 (A), the molding material M flows in the direction of arrow 1511 due to the filling process. Then, when the position of the screw 330 reaches the set position, a V/P switch is performed from the filling process to the pressure holding process.

In the situation shown in FIG. 5B, after the V/P switch is performed, the screw 330 slowly retreats as shown by the arrow 1521. The molding material M flows in the direction shown by the arrow 1522 due to pressure relief.

In the subsequent situation shown in FIG. 5C, in the pressure holding 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 kept at a set pressure, and the molding material remaining in the cylinder 310 is pushed toward the mold device 800. As a result, the molding material M moves in the direction indicated by the arrow 1523.

In the subsequent situation shown in FIG. 5(D), during the pressure holding process, the molding material M moves in the direction indicated by the arrow 1524, discharging the gas and filling the flow path with molding material M up to the end (a so-called packed state).

The control associated with the movement of the molding material shown in FIG. 5 is an example, and is not limited to the above-mentioned control. For example, the timing of switching from the filling process to the pressure holding process is an example, and the process may be switched to the pressure holding process at the timing of transition to the packed state, or after transition to the packed state. Furthermore, pressure holding may be performed during the filling process.

Fig. 6 is a diagram showing the change in temperature and pressure from the start of filling to pressure holding. In the example shown in Fig. 6, the change in temperature 1601 and pressure 1602 detected by the sensor 841 is shown. In the example shown in Fig. 6, the speed of the screw 330 is controlled as the filling process. Then, at time _T11 , the filling process is switched to the pressure holding process, that is, the so-called V/P switching is performed. In the maintenance process that follows, the molding material remaining in the cylinder 310 is pushed toward the mold device 800 while the holding pressure of the molding material at the front end of the screw 330 is held at the set pressure.

The gas pressure 1602 in the cavity space 801, which had been rising due to the filling process, switches to the pressure holding process and after a short time has passed, it begins to decrease.

At time _T12 , the molding material M is filled up to the end of the flow path (so-called packed state). That is, the molding material M comes into contact with the sensor 841, and the temperature 1601 rises. In other words, the timing when the sensor 841 detects a steep rise in temperature (inflection point) is the timing when the molding material M is filled up to the end of the flow path (packed).

In this embodiment, when the difference between the previously detected temperature and the currently detected temperature exceeds 10 degrees, the judgment unit 713 judges that the molding material M has reached the end of the flow path (at the time of packing). Note that the judgment method based on whether the temperature difference according to this embodiment exceeds 10 degrees is an example of a judgment method at the time of packing, and is not limited to this method, and other methods may be used. In addition, the judgment condition "10 degrees" may be set to an appropriate value depending on the embodiment. As a judgment method at the time of packing, for example, a case where the distance sensor of the sensor 841 judges that the distance to the end of the flow front of the molding material M is "0" may also be used.

After the packed state is reached at time _T12 , the sensor 841 detects the pressure of the molding material (resin pressure). Thus, when the packed state is reached at time _T12 , the detected pressure switches from the gas pressure to the molding material pressure (resin pressure). This causes the detected pressure to increase.

However, when injection molding is repeated, components of the molding material M accumulate on the parting surface 830, forming a mold deposit. If the volume of the mold deposit increases, it becomes difficult for the gas in the cavity space 801 to be discharged to the outside of the cavity space 801 while the molding material M is being filled. As a result, the gas remaining in the cavity space 801 becomes hot due to adiabatic compression, causing the molded product to burn and become defective.

In other words, when gas burning occurs, the temperature rises sharply just before packing due to adiabatic expansion of the gas present at the end of the flow path of the mold device 800. Together with the temperature, the pressure in the cavity space 801 also rises.

Conventionally, during the post-molding inspection process, workers would check the molded product to determine whether gas burns had occurred. If gas burns were determined to have occurred, it would be assumed that the accumulation of mold deposits had made it difficult for the gas to escape, and production of molded products would be stopped and the mold equipment cleaned. When this method is used, it is not possible to determine whether gas burns have occurred until the molded product is inspected, which results in the production of multiple defective products with gas burns.

The control device 700 according to this embodiment therefore judges whether or not gas burning has occurred in the molded product based on the pressure detected by the sensor 841 around the time when the product becomes in a packed state. The judgement that gas burning has occurred according to this embodiment is not limited to the actual occurrence of gas burning, but also includes a state in which there is a high possibility of gas burning occurring. In other words, in this embodiment, if a pressure similar to that in which gas burning has occurred is detected based on the correspondence between previously detected pressures and gas burning, a judgement is made to consider that gas burning has occurred, regardless of whether gas burning has actually occurred.

Figure 7 is a diagram illustrating an example of the change in pressure detected by the sensor 841 when the mold device 800 according to this embodiment is in a packed state. The horizontal axis shows the number of shots (example of the number of injections) from the time when the mold device 800 is cleaned, and the vertical axis shows the pressure detected when the packed state is reached (in other words, when it is determined that the packed state has been reached based on the detected temperature). Lines 1701 to 1705 have the same injection conditions, etc., but differ in cleaning state, etc.

Lines 1701 to 1705 in Figure 7 show that the pressure at the time the pack state is reached gradually increases with each molded product produced from the time cleaning is performed, in other words, with each increase in the number of shots.

In the example shown in Figure 7, for each of lines 1701 to 1705, the pressure rises sharply when it exceeds threshold value Pth1. This is because an increase in the volume of the mold deposit makes it difficult for gas to be discharged to the outside of cavity space 801, causing a large amount of gas to accumulate in cavity space 801, and the pressure rises sharply when the temperature rises due to adiabatic compression. In other words, it can be inferred that gas burns have occurred in the molded product when the detected pressure exceeds threshold value Pth1.

Each of lines 1701 to 1704 has a different number of shots required to reach threshold Pth1, depending on the cleaning state of the mold device 800 or the environment in which injection molding is performed. However, they have in common that gas burns occur in the molded product when the pressure detected by the sensor 841 exceeds threshold Pth1. Line 1705 is a case in which, within the range shown in Figure 7, the pressure when the packed state is reached does not reach threshold Pth1, and no gas burns occur in the molded product. In other words, this means that no gas burns will occur in the molded product if threshold Pth1 is not reached, even if the number of shots is large.

Therefore, in the control device 700 according to this embodiment, whether or not gas burning has occurred is determined based on whether or not the pressure when the packed state is reached (in other words, when it is determined that the packed state has been reached based on the detected temperature) exceeds the threshold value Pth1. Note that this embodiment does not limit the timing for determining whether or not gas burning has occurred to when the packed state is reached. However, since the timing when the gas is packed roughly coincides with the timing when gas burning occurs, the accuracy of determining whether or not gas burning has occurred can be improved by using the pressure when the gas is packed for the determination.

Returning to Figure 3, we will now explain each component of the control device 700.

The setting unit 711 sets a threshold value Pth1, which is a criterion for determining whether gas burning has occurred. For example, the threshold value Pth1 is set to the pressure detected by the sensor 841 when gas burning occurs during repeated production of molded products in the injection molding machine 10. The set threshold value Pth1 may be a value input by the user from the operation device 750, or may be automatically set by the control device 700.

The acquisition unit 712 acquires signals (an example of information) indicating detection results from various sensors provided in the injection molding machine 10. For example, the acquisition unit 712 acquires signals indicating detection results based on pressure and temperature from the sensor 841. This allows the acquisition unit 712 to acquire signals indicating pressure and temperature from the sensor 841 provided near the end of the cavity space 801 in the mold device 800 of the injection molding machine 10, where the molding material filled in the cavity space 801 ends up.

The determination unit 713 determines whether the molding material has filled the mold device 800 up to the flow end based on the temperature from the sensor 841 acquired by the acquisition unit 712. Note that this embodiment is not limited to a method of detecting the pressure exactly when the molding material has filled the mold device 800 up to the flow end. In other words, the increase in pressure that causes gas burns does not occur only at the timing when the molding material is filled, but occurs any time around that timing. In other words, it is preferable to set the timing of detecting the pressure within, for example, ±0.05 seconds from the timing when the molding material has filled the mold device 800 up to the flow end.

Furthermore, the determination of whether the molding material has filled the flow end of the mold device 800 is not limited to a method using temperature, but may be determined based on the distance to the molding material detected by the sensor 841. For example, it may be determined that the molding material has filled when the distance from the sensor 841 to the molding material becomes "0".

Then, the determination unit 713 determines whether or not the pressure detected by the sensor 841 exceeds the threshold value Pth1 set by the setting unit 711 near the timing when the molding material is filled up to the flow end of the mold device 800 (when the mold device 800 is in a packed state). If the pressure detected by the sensor 841 exceeds the threshold value Pth1 set by the setting unit 711, it is determined that gas burning has occurred.

In this embodiment, the timing for determining whether or not gas burning has occurred is not limited to the timing near the timing when the molding material is filled up to the end of the flow (packed state). In other words, since gas burning occurs when it becomes difficult for gas to be discharged from the mold device 800, if it can be detected that it is becoming difficult for gas to be discharged from the mold device 800, it can be determined whether or not gas burning has occurred. For example, the determination unit 713 may determine that gas burning has occurred when the pressure detected by the sensor 841 near the V/P switch exceeds the threshold value Pth2. The determination that gas burning has occurred in this embodiment is not limited to actual gas burning, but also includes a state in which there is a high possibility that gas burning has occurred.

Figure 8 is a diagram illustrating the change in pressure detected by the sensor 841 when V/P is switched in the mold device 800 according to this embodiment. The horizontal axis shows the number of shots since the mold device 800 was cleaned, and the vertical axis shows the pressure detected when V/P was switched.

Lines 1801 and 1802 in Figure 8 show that the pressure at V/P switching gradually increases with each molded product produced from the time cleaning was performed, in other words, with each increase in the number of shots. Lines 1801 and 1802 show cases where molding conditions (e.g., the design of the screw 330) are different.

Then, the judgment unit 713 may judge whether the pressure detected by the sensor 841 at the time of V/P switching exceeds the threshold value Pth2. Then, if the pressure detected by the sensor 841 at the time of V/P switching exceeds the threshold value Pth2, it is judged that gas burning will occur. Note that the method is not limited to detecting the pressure exactly at the time of V/P switching. It is preferable to set the timing of detecting the pressure to, for example, within ±0.05 seconds from the time of V/P switching.

The log control unit 714 performs control to store the log information of the injection molding machine 10 in the log storage unit 721. For example, when the determination unit 713 determines that it is packing time, the log control unit 714 may include the pressure detected by the sensor 841 in the log information and store it in the log storage unit 721.

For example, the log control unit 714 stores the actual values during molding, setting information, calculated statistical values, etc. as log information in the log storage unit 721. Settings for saving as log information are made on the log information screen displayed by the display control unit 715.

In addition, when determining whether or not gas has burned based on the pressure detected by the sensor 841 at the time of V/P switching, the log control unit 714 may include the pressure detected by the sensor 841 in the log information and store it in the log storage unit 721 when it is determined that V/P switching has occurred.

The display control unit 715 controls the display of data such as the display screen on the display device 760.

The display control unit 715 according to this embodiment may output, for each step of the molding process by the injection molding machine 10, a display screen including setting information set by the user in that step or actual values detected in that step to the display device 760. Note that, although this embodiment describes an example of outputting a display screen or the like to the display device 760, the output destination of data is not limited to the display device 760. For example, the display control unit 715 may output data such as a display screen to a communication terminal connected via a network.

The display control unit 715 in this embodiment displays a log information screen that displays, for example, actual values during molding, setting information, statistical values, etc. as log information.

Figure 9 is a diagram illustrating an example of a log information screen output by the display control unit 715 according to this embodiment.

The log information screen 1400 shown in FIG. 9 displays a total number 1401, a number of good items 1402, a number of defective items 1403, a number of rejected items 1404, a logging button 1405, a monitoring settings button 1406, a save button 1407, an update button 1408, a statistics list 1420, and a performance list 1430.

Statistics list 1420 shows statistical values (e.g., average, range, maximum, minimum, standard deviation) for each of setting fields 1421 to 1428. The contents shown in setting fields 1421 to 1428 can be set by the user. In this embodiment, it is possible to display, monitor, and save log information for the items shown in setting fields 1421 to 1428. Note that monitoring in this embodiment refers to determining whether or not an item is good based on a predetermined standard.

The "Monitoring", "Upper Limit", and "Lower Limit" in the statistics list 1420 are used to determine whether the molded product in the corresponding setting field is defective or not.

When monitoring in the statistics list 1420 is "OFF", the control device 700 does not perform monitoring, and when it is "ON", the control device 700 performs monitoring. When it is "ON", the control device 700 determines whether the measured performance value for the item indicated in the setting field meets the criteria indicated by the "upper limit" and "lower limit". The monitoring can be switched using the monitoring setting button 1406.

"Defective" in the statistics list 1420 indicates the number of molded parts that do not fall within the range indicated by the "upper limit" and "lower limit".

Settings or performance values related to injection molding are set in setting fields 1421 to 1428. Note that setting fields 1421 to 1428 can be changed by the user to the items they wish to monitor. Explanation of how to change these settings is omitted.

The performance list 1430 represents a list of the setting information for the items set in the setting fields 1421 to 1428 or the performance values measured by various sensors for each shot. The items set in the setting fields 1421 to 1428 are set from "CH-1" to "CH-8". In addition, each shot is associated with information indicating the shot, such as the "shot number", the "time" at which the injection molding was performed, and the "status" of the injection molding.

The logging button 1405 is a button that accepts whether or not to save at least one of the setting values and performance values shown in the performance list 1430 as log information. When the logging button 1405 is pressed (displays "Logging On"), the log control unit 714 saves the information shown in the performance list 1430, etc., in the log storage unit 721 as log information.

The monitoring setting button 1406 is a button that accepts whether or not to monitor according to the monitored items in the statistics list 1420. When the monitoring setting button 1406 is pressed (displays "Monitoring On"), each shot is monitored for defects, and the monitoring results are included in the log information. Depending on whether the monitoring setting button 1406 is pressed, monitoring of the statistics list 1420 switches to "Off" or "On".

When the monitoring setting button 1406 is set to "On," monitoring is performed according to the "Monitoring" setting in the statistics list 1420 described above.

For example, "pressure during packing" in setting column 1428 is an item in which the actual value of the pressure detected by sensor 841 during packing is set. In this embodiment, "on" is set for "pressure during packing" in "monitoring" column 1629. For example, "20.00" (MPa) is set in upper limit column 1629A as threshold value Pth1. As a result, when judgment unit 713 judges that the pressure during packing is higher than "20.00" (an example of threshold value Pth1), number of defects 1403 increases.

Note that this embodiment shows an example of threshold value Pth1 and is not limited to "20.00". Threshold value Pth1 varies depending on, for example, the shape of mold device 800 or the type of molding material.

The save button 1407 is a button that accepts whether or not to save the statistical values (e.g., average, range, maximum, minimum, integral value, standard deviation, etc.) for each of the setting fields 1421 to 1428. When the save button 1407 is pressed, the log control unit 714 saves the statistical values for each of the setting fields 1421 to 1428 in the log storage unit 721 as log information.

The update button 1408 is a button that accepts whether or not to update the statistics list 1420 and the performance list 1430 each time injection molding is completed by the injection molding machine 10. When the update button 1408 is pressed (displays "Always"), the statistics list 1420 and the performance list 1430 are updated each time injection molding is completed by the injection molding machine 10.

The total number 1401 indicates the number of molded products molded by the injection molding machine 10. The number of good products 1402 indicates the number of molded products that were determined to be good products based on the "monitoring", "upper limit", and "lower limit". The number of defective products 1403 indicates the number of molded products that were determined to be defective products based on the "monitoring", "upper limit", and "lower limit". The number of rejected products 1404 indicates the number of rejected molded products.

The display control unit 715 according to this embodiment displays "20.00" (MPa) in the upper limit column 1629A on the log information screen of the display device 760, and also displays the transition of the pressure detected during packing in the performance list 1430. This allows the user to recognize whether or not gas burns are occurring in the molded products produced by the injection molding machine 10.

In this embodiment, the screen displayed by the display control unit 715 is not limited to the log information screen. For example, the display control unit 715 may display a graph showing the transition of pressure against the number of shots during packing, as shown in FIG. 7. The threshold value Pth1 may be displayed as a line on the graph.

As another example, the display control unit 715 may display a graph showing the transition of pressure versus the number of shots when V/P is switched, as shown in FIG. 8. The graph may display the threshold value Pth2 as a line.

As a modified example, the determination unit 713 may not make a determination, and the display control unit 715 may simply display the graph shown in FIG. 7 or FIG. 8. By referring to the graph shown in FIG. 7 or FIG. 8, the user can determine the number of shots required until gas burning occurs, and whether or not gas burning has occurred.

In this embodiment, if the determination unit 713 determines that the pressure detected by the sensor 841 exceeds the threshold value Pth1 at the time when the packed state is achieved, the display control unit 715 displays a screen indicating that "gas burn has occurred in the molded product" on the log information screen 1400. The screen to be displayed may be, for example, a pop-up screen.

This allows the user to recognize that gas burn has occurred. Note that the information output when it is determined that the pressure detected by the sensor 841 exceeds the threshold value Pth1 at the time when the packed state is reached is not limited to the display screen. For example, the control device 700 may output a sound indicating that gas burn has occurred, or may notify a communication terminal connected via a network that gas burn has occurred.

Next, the process steps for detecting gas burns in the injection molding machine 10 according to this embodiment will be described. Figure 10 is a flowchart showing the process steps for detecting gas burns in the injection molding machine 10 according to this embodiment.

First, the injection molding machine 10 repeats the production of molded products until gas burns occur (S2001). When gas burns occur, the control device 700 recognizes the pressure detected by the sensor 841 during packing.

Then, the setting unit 711 of the control device 700 sets the pressure detected when gas burning occurs as the threshold value Pth1 (S2002).

Then, the injection molding machine 10 starts producing the molded product under the control of the control device 700 (S2003).

Then, the acquisition unit 712 acquires the pressure detected by the sensor 841 during packing (S2004). During packing, the determination unit 713 identifies the pressure based on the temperature detected by the sensor 841, as described above.

Then, the judgment unit 713 judges whether the acquired pressure exceeds the set threshold value Pth1 (S2005). If it is judged that the acquired pressure does not exceed the set threshold value Pth1 (S2005: NO), the injection molding machine 10 produces the next molded product, and the process of S2004 is performed again.

On the other hand, if the determination unit 713 determines that the acquired pressure exceeds the threshold value Pth1 (S8005: YES), the display control unit 715 displays a pop-up screen indicating that gas burning has occurred, and the control device 700 outputs a notification sound (S2006).

In this embodiment, the above-mentioned control allows the user to recognize that gas burn has occurred.

(Modification of the first embodiment)
In this embodiment, an example has been described in which it is determined whether or not gas burning has occurred based on the pressure detected near the time of packing or near the time of V/P switching. However, this embodiment is not limited to determining whether or not gas burning has occurred based on whether or not a pressure equal to or greater than a threshold value has been detected. Therefore, in a modified example, it is determined whether or not gas burning has occurred based on the difference in detected pressure.

As shown in Figure 7, if gas burning occurs, the pressure during packing rises sharply. In other words, if the pressure detected this time is higher than the pressure detected during packing up until now, it can be inferred that gas burning has occurred.

For this reason, the determination unit 713 in this modified example determines whether the difference between the pressure detected during the previous packing and the pressure detected during the current packing is greater than a predetermined value. The predetermined value is, for example, a value between 1 and 1.5 MPa. Note that the predetermined value is a value that is set depending on the implementation, and is not limited to 1 to 1.5 MPa.

In this modified example, a judgment is made based on the difference in pressure between two consecutive pressures detected during packing. However, in this modified example, the judgment is not limited to being based on the difference in pressure between two consecutive pressures, and may be three or more pressures. Furthermore, the judgment is not limited to being based on the difference in pressure, and may be made using a moving average. For example, it may be determined whether or not gas burning has occurred based on a moving average of three pressures. In other words, the judgment unit 713 may determine whether or not gas burning has occurred based on the difference between the moving average calculated this time and the moving average calculated last time.

In addition, this modified example does not determine whether gas burning has occurred based on multiple consecutive pressure differences detected near the time of packing or near the time of V/P switching, but may determine whether gas burning has occurred based on pressure differences detected every other time near the time of packing or near the time of V/P switching (in other words, multiple discontinuous pressure differences).

In other words, the judgment unit 713 judges that gas burns have occurred in the molded product produced by the second injection molding when the difference in pressure detected near the time of packing or near the time of V/P switching between the first injection molding and the second injection molding performed after the first injection molding satisfies a predetermined condition.

In the above-described embodiment, whether or not gas burning has occurred is determined based on whether or not the pressure exceeds a threshold value, and in the modified example, an example has been described in which whether or not gas burning has occurred is determined based on whether or not the pressure difference is greater than a predetermined value. However, in the above-described embodiment and modified example, the method of determining whether or not gas burning has occurred is not limited to the above-described method. In other words, it is sufficient to be able to determine whether or not gas burning has occurred in the molded product based on preset conditions regarding the pressure detected by the sensor 841. In other words, it is preferable to set the determination based on predetermined conditions regarding the pressure at the flow end of the molding material filled in the cavity space 801.

In the above-described embodiment and modified examples, gas burns can be detected immediately without an operator inspecting the molded product, which prevents the production of molded products from continuing when gas burns have occurred.

Second Embodiment
In the above-described embodiment, an example of determining whether or not gas burning has occurred has been described. However, as in the above-described embodiment and modified example, the determination of whether or not gas burning has occurred is not limited to the determination based on the pressure detected near the time of packing or near the time of V/P switching. In other words, the period until gas burning occurs may be predicted based on a change in pressure detected near the time of packing or near the time of V/P switching.

The period until gas burning occurs indicates how long it will be before gas burning occurs, and is one or more of the number of times (e.g., the number of shots, the number of moldings, or the number of productions (production volume)) and the time (e.g., the operating time, the molding time, or the production time). The period until gas burning occurs is not limited to the number of times or the time shown as a number or a character string, but may be represented by a diagram or the like. Below, an example of predicting the number of shots and time (e.g., the operating time) will be described as an example of predicting the period.

Conventionally, in injection molding machines, the production of molded products is repeated in a predetermined cycle. The predetermined cycle is, for example, production, gas burning of the molded product, and cleaning of the mold device. By repeating such a cycle, it is possible to determine the number of shots required until gas burning occurs in the molded product. For example, gas burning occurs after 10,000 shots in the first production run, after 6,000 shots in the second production run, and after 13,000 shots in the third production run.

In other words, the number of shots until gas burns occur varies depending on many factors, such as the lot of the molding material (subtle differences in composition), the moisture content of the molding material, the condition of the mating surfaces between the fixed and movable dies, the surface condition of the tubular mold device, how clean the mold device is, the degree of gas generation from the molding material (variation in plasticization), the temperature of the mold device, the dimensions of the mold device, and the clamping force.

In the conventional method described above, therefore, it is possible to stop production after the fourth shot at a predetermined number of shots to prevent gas burns. In this case, the number of shots is set to, for example, 5,000 shots so that gas burns do not occur. In other words, gas burns can be prevented by cleaning the mold device after 5,000 shots. However, if the mold device is cleaned after 5,000 shots, production must be stopped. In this case, even though production could have been completed without gas burns up to 13,000 shots, production is stopped at 5,000 shots, which increases the burden of cleaning the mold device and may reduce production efficiency.

The log control unit 714 in this embodiment predicts the time until gas burning occurs based on the change in pressure detected by the sensor 841 near the time of V/P switching or near the time of packing. In other words, the log control unit 714 calculates the number of shots and time until the conditions for gas burning are met based on the change between the pressure detected near the time of V/P switching or near the time of packing of the first injection molding and the pressure detected near the time of V/P switching or near the time of packing of the second injection molding performed after the first injection molding. Then, the display control unit 715 displays the calculated number of shots and time (an example of a period).

In this embodiment, an example is described in which the predicted number of shots and the predicted time until gas burns occur are displayed, but it is acceptable to display one or more of the number of shots and the time.In this embodiment, an example is described in which the number of shots and the time are displayed as the period until gas burns occur in the molded product, but the output method is not limited to display, and may be audio output or transmission to a communication terminal.

In other words, as shown in Figures 7 and 8 of the first embodiment, when gas burns occur, pressure equal to or exceeds the threshold value described above occurs near the time of V/P switching or packing. Therefore, in this embodiment, the log control unit 714 estimates the number of shots required to exceed the threshold value based on the degree of change in pressure detected near the time of V/P switching or packing.

The log control unit 714 according to this embodiment calculates an approximation equation showing the correspondence between the number of shots and the detected pressure based on multiple pressure values detected by the sensor 841 during packing. The approximation equation may be calculated using the pressure from the start of cleaning to the present, or may be calculated using the pressure for a predetermined number of shots (e.g., several tens of shots) up to the present. The approximation equation may be a linear equation, a quadratic equation, a cubic equation, or the like.

For example, in the example shown in FIG. 7, the rate of increase increases as the detected pressure approaches the threshold value Pth1. For this reason, when calculating an approximation equation using the pressure from the start of cleaning to the present, a quadratic or cubic equation is preferable. On the other hand, when using a linear equation as the approximation equation, it is preferable to use the pressure for a certain number of shots up to the present (for example, the pressure for several tens of shots).

In addition, the log control unit 714 is not limited to a method of calculating an approximation equation showing the pressure detected by the sensor 841 during packing, but may calculate an approximation equation showing the correspondence between the number of shots and pressure based on the pressure detected by the sensor 841 during V/P switching.

In the example shown in Figure 8, lines 1801 and 1802 show that the pressure at V/P switching gradually increases each time a molded product is produced from the time cleaning is performed, in other words, each time the number of shots increases.

When the log control unit 714 detects a change in pressure as shown by line 1801, it calculates the approximation equation "y = a1 x + b1" as shown by line 1811. The variables a1 and b1, where x is the number of shots and y is the pressure, are assigned based on the change in pressure as shown by line 1801.

When the log control unit 714 detects a change in pressure as shown by line 1802, it calculates the approximation equation "y = a2 x + b2" as shown by line 1812. The variables a2 and b2, where x is the number of shots and y is the pressure, are assigned based on the change in pressure as shown by line 1802.

In other words, in the example shown in FIG. 8, the log control unit 714 calculates the approximation formula, and then substitutes the threshold value Pth2 for y in the approximation formula to derive the number of shots x at which gas burns are predicted to occur. The log control unit 714 can also calculate the time until gas burns occur from the number of shots x at which gas burns are predicted to occur and the time required for each shot. This calculation method may be applied not only when V/P is switched, but also when packing as described above.

In the example shown in Figure 8, the case where the approximation formula is a linear expression is described, but a similar calculation method can be used when the approximation formula is a quadratic or cubic expression.

The number of shots and time until gas burn occurs, calculated by the log control unit 714, are then displayed by the display control unit 715.

Figure 11 is a diagram illustrating an example of a gas burn prediction information screen output by the display control unit 715 according to this embodiment.

The gas burn prediction information screen 2100 shown in FIG. 11 displays pack detection 2101, pressure at gas burn 2102, predicted number of shots until gas burn 2103, predicted time until gas burn 2104, gas burn prediction alarm 2105, and alarm notification setting 2106.

Pack detection 2101 sets whether or not to detect pack time. Pack detection 2101 is set, for example, according to an input from the operation device 750. Pack detection 2101 can be switched between "Auto" and "Off". When pack detection 2101 is set to "Auto", the determination unit 713 performs the above-mentioned pack time detection.

The pressure at gas burning 2102 sets the pressure (threshold) at which gas burning is detected. The pressure at gas burning 2102 is set, for example, according to an input from the operation device 750. In this embodiment, when the pressure is set, the determination unit 713 determines whether or not gas burning has occurred based on the pressure (threshold), and the log control unit 714 calculates the number of shots and the time until gas burning occurs based on the set pressure (threshold).

The predicted number of shots until gas burns occur 2103 displays the number of shots until gas burns occur, calculated by the log control unit 714.

The predicted time until gas burning 2104 displays the time until gas burning occurs, calculated by the log control unit 714.

The gas burn prediction alarm 2105 sets whether or not to output an alarm before gas burn occurs. The gas burn prediction alarm 2105 is set, for example, according to an input from the operation device 750. The gas burn prediction alarm 2105 can be switched between "on" and "off." When the gas burn prediction alarm 2105 is set to "on," the control device 700 outputs an alarm indicating that gas burn is approaching before gas burn occurs.

The alarm notification setting 2106 sets the timing for notifying an alarm. The alarm notification setting 2106 is set, for example, according to an input from the operation device 750. In this embodiment, an alarm is output at a timing that is the number of shots set in the alarm notification setting 2106 before the number of shots at which gas burn is predicted to occur.

For example, if the predicted number of shots until gas burn occurs is "1000" and the alarm notification setting 2106 is set to "10", an alarm will be output when the number of shots reaches "990". The alarm may be a sound, a pop-up screen, or a notification sent to a communication terminal.

The gas burn prediction information screen output by the display control unit 715 is not limited to the screen shown in FIG. 11, and may be in other forms. For example, the display control unit 715 may plot the pressure values detected by the sensor 841 as shown in FIG. 7 or FIG. 8 to display a diagram showing the pressure transition up to the present. A threshold value for determining whether or not gas burn has occurred may be superimposed on the diagram. Furthermore, a prediction of the pressure transition until the threshold value is reached may be displayed based on the pressure transition up to the present. The prediction of the pressure transition may be calculated by any method, regardless of whether it is a well-known method, and may be, for example, the approximation formula of FIG. 8 described above. The worker according to this embodiment can perform work while taking into consideration the display of the prediction of the period until gas burn occurs.

In this embodiment, an alarm is issued before gas burning occurs, allowing the operator to begin taking action to address the gas burn before it occurs.

Next, the processing procedure until an alarm is output in the control device 700 according to this embodiment will be described. FIG. 12 is a flowchart showing the processing procedure until an alarm is output in the control device 700 according to this embodiment.

The setting unit 711 of the control device 700 sets the pressure detected when gas burning occurs during packing as the threshold value Pth1 (S2201).

Then, the injection molding machine 10 starts producing the molded product under the control of the control device 700 (S2202).

Then, the acquisition unit 712 acquires the pressure detected by the sensor 841 during packing (S2003). During packing, the determination unit 713 identifies the pressure based on the temperature detected by the sensor 841, as in the above-described embodiment.

The log control unit 714 predicts (calculates) the number of shots and time until the threshold is exceeded based on the packing pressure acquired up to that point (S2004).

The display control unit 715 displays the predicted number of shots and time on the gas burn prediction information screen (S2005).

The determination unit 713 further determines whether the number of shots from the current number of shots until the number of shots that exceeds the threshold is equal to or less than the number of shots set in the alarm notification setting 2106 (S2206). If it is determined that the number of shots is greater than the set number of shots (S2206: NO), the process is repeated from S2203.

On the other hand, if the determination unit 713 determines that the number of shots from the current number of shots to exceed the threshold is equal to or less than the number of shots set in the alarm notification setting 2106 (S2206: YES), the control device 700 outputs a notification sound indicating an alarm (S2207). At this time, the display control unit 715 may display a pop-up screen indicating that gas burning is approaching.

In this embodiment, the above-mentioned control allows the user to be aware in advance that gas burning will occur.

In this embodiment, by performing the above-mentioned control, the time until gas burning and the number of shots can be predicted, and production can be continued until just before gas burning occurs. This reduces the frequency of cleaning the mold device 800, thereby improving productivity. Furthermore, because the frequency of cleaning is reduced, the cleaning burden can be reduced.

In this embodiment, the time and number of shots until gas burning can be predicted, so cleaning of the mold device 800 can be scheduled. This reduces the waiting time required to clean the mold device 800, thereby reducing the workload.

In this embodiment, production can be continued right up until the moment gas burns occur, minimizing the frequency of cleaning the mold device 800 and improving productivity.

In this embodiment, the time until gas burns occur can be predicted, allowing cleaning of the mold device 800 to be scheduled.

<Action>
In the above-described embodiment and modified examples, by having the above-described configuration, the control device 700 monitors gas burns in the molded product based on the detected pressure, thereby reducing the occurrence of defective products.

In the above-described embodiment and modified example, by providing the above-described configuration, it is possible to present information regarding gas burning (e.g., whether or not gas burning has occurred, or the predicted time until gas burning will occur, etc.) to the user without inspecting the molded product for gas burning. This allows immediate action to be taken regarding gas burning, and prevents production of molded products from continuing in a state where gas burning has occurred. This reduces the inspection burden and prevents production defects, thereby reducing production costs.

In the above-described embodiment, an example has been described in which the display device 760 displays information as a display device of an injection molding machine under the control of the control device 700. However, the above-described embodiment shows one aspect of the display device of an injection molding machine, and the present invention is not limited to this aspect.
For example, a control device within the display device 760 may perform control for displaying information.

The above describes the embodiments of the control device for an injection molding machine and the display device for an injection molding machine according to the present invention, but the present invention is not limited to the above-mentioned 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.

10 Injection molding machine 700 Control device 701 CPU
711 Setting unit 712 Acquisition unit 713 Determination unit 714 Log control unit 715 Display control unit 702 Storage medium 721 Log storage unit

Claims (5)

an acquisition unit configured to acquire information indicating pressure from a detection unit provided in a cavity space in a mold device of an injection molding machine near an end portion to which a molding material filled in the cavity space reaches;
a control unit configured to determine whether or not gas burning has occurred in a molded product produced by the injection molding machine, based on a predetermined condition related to the pressure detected near the timing of switching from a filling process to a pressure holding process in the injection molding machine, or near the timing when the molding material is filled up to the end, or to predict or display a period until gas burning occurs in the molded product;
A control device for an injection molding machine comprising: the control unit determines that gas burning has occurred in the molded product produced by the injection molding machine when the pressure detected at the timing exceeds a threshold value defined as the predetermined condition.
The control device for an injection molding machine according to claim 1. the control unit determines that gas burning has occurred in the molded product produced by the second injection molding when a difference between the pressure detected at the timing of a first injection molding and the pressure detected at the timing of a second injection molding performed after the first injection molding is greater than a value defined as the predetermined condition.
The control device for an injection molding machine according to claim 1. the control unit calculates the time or the number of injections required to satisfy the predetermined condition based on a change between the pressure detected at the timing of the first injection molding and the pressure detected at the timing of the second injection molding performed after the first injection molding, and outputs information related to the time or the number of injections.
The control device for an injection molding machine according to claim 1. an acquisition unit configured to acquire information indicating pressure from a detection unit provided in a cavity space in a mold device of an injection molding machine near an end portion to which a molding material filled in the cavity space reaches;
a display control unit configured to display a screen showing a transition of the pressure detected near the timing of switching from a filling process to a pressure holding process in the injection molding machine or near the timing of filling the end with the molding material, and information showing a standard of the pressure at which gas burns occur in a molded product produced by the injection molding machine; and
A display device of an injection molding machine comprising:

Images