JP2023126444A - Injection molding machine - Google Patents

Abstract

To provide an injection molding machine capable of suppressing an overload state of an actuator that drives a pressurizing device to pressurize a molding material filled into a mold device such as an ejector device or a core tractor device.SOLUTION: An injection molding machine comprises a pressurizing device, a control device, and a display device. A display device 760 of the injection molding machine 10 displays a setting screen 1000 for making settings regarding control of a torque of an ejector motor 221 by a control device 700 based on a mold pressure inside a cavity space 801 of a mold device 800, which represents a force resisting the drive of the ejector motor 221. The setting screen 1000 can perform the setting input regarding a magnitude of the torque when maintaining the torque of the ejector motor 221 in a relatively high state, the setting input regarding a magnitude of the torque when maintaining the torque of the ejector motor 221 in a relatively low state, or the setting input regarding how to change the torque of the ejector motor 221 when moving from a relatively high state to a low state.SELECTED DRAWING: Figure 10

Description

The present disclosure relates to injection molding machines.

For example, in an injection molding machine, ejector compression may be performed to compress the molding material (resin) inside the mold (cavity space) using an ejector (for example, see Patent Document 1).

Furthermore, a technique is known in which a stopper is provided on the ejector to limit the amount of movement (for example, see Patent Document 2).

Patent No. 5850990 Patent No. 4095013

However, for example, the actuator may be controlled to press the ejector against the mechanical end (stopper) to prevent the tip of the movable member from shifting from an appropriate position due to pushback from the molding material in the cavity when the ejector is compressed. . In this case, since the actuator continues to output a relatively high torque, the actuator may fall into an overload state, and as a result, the injection molding machine may stop abnormally.

A similar situation can also occur during ejector compression for transfer purposes, regardless of the presence or absence of a mechanical end. For example, in order to reliably transfer the pattern of the tip of the movable member to the molding material in the cavity space, it is necessary to continue pressing the tip of the movable member against the molding material for a certain period of time, and the actuator is required to apply a relatively high torque. This is because there is a possibility that it will continue to issue.

A similar situation can also occur when compressing the molding material inside the mold (inside the cavity) using a core tractor (hereinafter referred to as "core compression"). For example, when the core is compressed, the actuator is controlled to press against the mechanical end to prevent the tip of the core from shifting from its proper position due to pushback from the molding material in the cavity, which may cause the actuator to continue to output relatively high torque. Because there is.

Furthermore, a similar situation may occur when the ejector cuts the gate inside the mold. For example, when cutting a gate in a mold, it is necessary to keep the cutting edge pushed into the gate part for a certain period of time to separate the gate part, and the actuator may continue to output relatively high torque.

Therefore, in view of the above problems, it is possible to suppress the overload state of the actuator that drives the pressurizing device that pressurizes the molding material filled into the mold device such as the ejector device and the core tractor device in the injection molding machine. The purpose is to provide technology.

To achieve the above object, in one embodiment of the present disclosure,
A pressurizing device including a pressurizing mechanism that pressurizes a molding material filled in a mold device, and an actuator that drives the pressurizing mechanism;
a control device that controls the pressurizing device;
a display device;
The display device displays a screen for making settings related to control of the torque of the actuator by the control device based on a physical quantity related to a force opposing the drive of the actuator,
On the screen, a first setting input regarding the magnitude of torque in a first control state that maintains the torque of the actuator at a relatively high torque, and a second setting input regarding the magnitude of the torque in a first control state that maintains the torque of the actuator at a relatively low torque. a second setting input regarding the magnitude of the torque in the control state, or a second setting input regarding how to change the torque of the actuator when the torque of the actuator is transferred from the first control state to the second control state. It is possible to input 3 settings.
An injection molding machine is provided.

According to the embodiment described above, in an injection molding machine, it is possible to suppress an overload state of an actuator that drives a pressurizing device that pressurizes a molding material filled into a mold device such as an ejector device or a core tractor device. technology.

FIG. 1 is a diagram showing an example of an injection molding machine. FIG. 1 is a diagram showing an example of an injection molding machine. FIG. 2 is a front perspective view showing an example of an ejector device. It is a rear perspective view which shows an example of an ejector device. FIG. 2 is a plan sectional view showing an example of an ejector device. FIG. 6 is a side cross-sectional view showing the state of the movable member before ejector compression starts. FIG. 3 is a side sectional view showing the state of the movable member when the ejector is compressed. It is a time chart showing the operation status during ejector compression of the injection molding machine according to the comparative example. It is a time chart showing the operation status during ejector compression of the injection molding machine according to the embodiment. FIG. 3 is a diagram showing an example of a setting screen related to a control torque pattern displayed on a display device.

Embodiments will be described below with reference to the drawings.

[Injection molding machine configuration]
<Injection molding machine>
FIG. 1 is a diagram illustrating a state of an injection molding machine according to an embodiment when mold opening is completed. FIG. 2 is a diagram showing a state of the injection molding machine according to one embodiment during mold clamping. In this specification, the X-axis direction, the Y-axis direction, and the Z-axis direction are directions perpendicular to each other. The X-axis direction and the Y-axis direction represent the horizontal direction, and the Z-axis direction represents the vertical direction. When the mold clamping device 100 is 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 in the Y-axis direction is called the operation side, and the positive side in the Y-axis direction is called the counter-operation side.

As shown in FIGS. 1 and 2, the injection molding machine 10 includes a mold clamping device 100 that opens and closes a mold device 800, an ejector device 200 that ejects a molded product molded in the mold device 800, and a mold device 800 that ejects a molded product formed by the mold device 800. an injection device 300 that injects molding material into the mold, a moving device 400 that moves the injection device 300 forward and backward with respect to the mold device 800, a control device 700 that controls each component of the injection molding machine 10, and each of the injection molding machines 10. It has a frame 900 that supports the components. Frame 900 includes a mold clamping device frame 910 that supports mold clamping device 100 and an injection device frame 920 that supports 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 interior space of the injection device frame 920. Each component of the injection molding machine 10 will be explained below.

<Mold clamping device>
In the description of the mold clamping device 100, the moving direction of the movable platen 120 when the mold is closed (for example, the X-axis positive direction) is referred to as the front, and the moving direction of the movable platen 120 when the mold is opened (for example, the X-axis negative direction) is referred to as the rear. do.

The mold clamping device 100 performs mold closing, pressurization, mold clamping, depressurization, and mold opening of the mold device 800. Mold device 800 includes a fixed mold 810 and a movable mold 820.

The mold clamping device 100 is, for example, horizontal, and the mold opening/closing direction is horizontal. The mold clamping device 100 includes a fixed platen 110, a movable platen 120, a toggle support 130, a tie bar 140, a toggle mechanism 150, a mold clamping motor 160, a motion conversion mechanism 170, and a mold thickness adjustment mechanism 180.

Fixed platen 110 is fixed to mold clamping device frame 910. A fixed mold 810 is attached to a surface of the fixed platen 110 facing the movable platen 120.

The movable platen 120 is arranged to be movable in the mold opening/closing direction with respect to the mold clamping device frame 910. A guide 101 for guiding the movable platen 120 is installed on the mold clamping device frame 910. A movable mold 820 is attached to a surface of the movable platen 120 facing the fixed platen 110. By moving the movable platen 120 forward and backward relative to the fixed platen 110, the mold device 800 is closed, pressurized, clamped, depressurized, and opened.

The toggle support 130 is arranged at a distance from the fixed platen 110 and is placed on the mold clamping device frame 910 so as to be movable in the mold opening/closing direction. Further, the toggle support 130 may be arranged to be movable along a guide laid on the mold clamping device 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 device frame 910, and the toggle support 130 is arranged to be movable in the mold opening/closing direction with respect to the mold clamping device frame 910. The fixed platen 110 may be fixed to the device frame 910 and may be arranged to be movable in the mold opening/closing direction with respect to the mold clamping device frame 910.

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 expand according to the mold clamping force. At least one tie bar 140 may be provided with a tie bar distortion detector 141 that detects distortion of the tie bar 140. Tie bar distortion detector 141 sends a signal indicating the detection result to control device 700. The detection results of the tie bar distortion detector 141 are used for detecting mold clamping force and the like.

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

The toggle mechanism 150 is disposed between the movable platen 120 and the toggle support 130, and moves the movable platen 120 relative to the toggle support 130 in the mold opening/closing direction. The toggle mechanism 150 includes a crosshead 151, a pair of links, and the like. Each of the pair of link groups includes a first link 152 and a second link 153 that are connected to each other with a pin or the like in a flexible manner. The first link 152 is swingably attached to the movable platen 120 with a pin or the like. The second link 153 is swingably attached to the toggle support 130 with a pin or the like. The second link 153 is attached to the crosshead 151 via a third link 154. When the crosshead 151 is moved forward and backward with respect to the toggle support 130, the first link 152 and the second link 153 are bent and extended, and the movable platen 120 is moved forward and backward with respect to the toggle support 130.

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

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 moves 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, a pulley, or the like.

The motion conversion mechanism 170 converts the rotational motion of the mold clamping motor 160 into linear motion of the crosshead 151. The motion conversion mechanism 170 includes a screw shaft and a screw nut that is threaded 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 a mold closing process, a pressure increasing process, a mold clamping process, a depressurizing process, a mold opening process, etc. under the control of the control device 700.

In the mold closing process, the movable platen 120 is advanced by driving the mold clamping motor 160 to advance the crosshead 151 at a set movement speed to the mold closing completion position, and the movable mold 820 is brought into contact with the fixed mold 810. . The position and moving speed of the crosshead 151 are detected using, for example, a mold clamping motor encoder 161. The mold clamping motor encoder 161 detects the rotation of the mold clamping motor 160 and sends a signal indicating the detection result to the control device 700.

Note that the crosshead position detector that detects the position of the crosshead 151 and the crosshead movement speed detector that detects the moving speed of the crosshead 151 are not limited to the mold clamping motor encoder 161, but general ones can be used. can. Furthermore, the movable platen position detector that detects the position of the movable platen 120 and the movable platen movement speed detector that detects the moving speed of the movable platen 120 are not limited to the mold clamping motor encoder 161, but may be general ones. can.

In the pressure increasing process, the mold clamping motor 160 is further driven to further advance the crosshead 151 from the mold closing completion position to the mold clamping position, thereby generating mold 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 increasing 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. A molded article is obtained by solidifying the filled molding material.

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

In the depressurization step, 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 retracting the movable platen 120 and reducing the mold clamping force. The mold opening start position and the mold closing completion position may be the same position.

In the mold opening process, the movable platen 120 is moved backward by driving the mold clamping motor 160 to move the crosshead 151 backward from the mold opening start position to the mold opening completion position at a set movement speed, and the movable mold 820 is moved between the fixed metal molds and the mold opening process. Separate from mold 810. Thereafter, the ejector device 200 ejects the molded product from the movable mold 820.

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

Setting conditions in the depressurization process and mold opening process are similarly set. For example, the moving speed and position (mold opening start position, moving speed switching position, and mold opening completion position) of the crosshead 151 in the depressurization process and the mold opening process are collectively set as a series of setting conditions. The mold opening start position, the moving speed switching position, and the mold opening completion position are arranged in this order from the front side toward the rear, and represent the starting point and ending point of the section in which the moving speed is set. A moving speed is set for each section. There may be one or more moving speed switching positions. The moving speed switching position does not need to be set. The mold opening start position and the mold closing completion position may be the same position. Further, the mold opening completion position and the mold closing start position may be the same position.

Note that instead of the moving speed, position, etc. of the crosshead 151, the moving speed, position, etc. of the movable platen 120 may be set. Further, the mold clamping force may be set instead of the crosshead position (for example, mold clamping position) or the movable platen position.

By the way, the toggle mechanism 150 amplifies the driving force of the mold clamping motor 160 and transmits it to the movable platen 120. The amplification factor is also called the toggle factor. The toggle magnification changes depending on the angle θ formed by the first link 152 and the second link 153 (hereinafter also referred to as “link angle θ”). The link angle θ is determined from the position of the crosshead 151. When the link angle θ is 180°, the toggle magnification is maximum.

When the thickness of the mold device 800 changes due to replacement of the mold device 800 or a change in the temperature of the mold device 800, the mold thickness is adjusted so that a predetermined mold 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. Adjust.

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 is, for example, screwed into a screw shaft 181 formed at the rear end of the tie bar 140, a screw nut 182 that is rotatably but not retractably held on the toggle support 130, and screwed onto the screw shaft 181. It has a mold thickness adjustment motor 183 that rotates a screw nut 182.

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 plurality of threaded nuts 182 via the rotational driving force transmission section 185. A plurality of screw nuts 182 can be rotated synchronously. Furthermore, by changing the transmission path of the rotational driving force transmission section 185, it is also possible to rotate the plurality of screw nuts 182 individually.

The rotational driving force transmission section 185 is composed of, for example, a gear. In this case, a passive 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 plurality of passive gears and the drive gear is located at the center of the toggle support 130. is held rotatably. Further, the rotational driving force transmission section 185 may be configured with a belt, a pulley, or the like instead of a gear.

The operation of mold thickness adjustment mechanism 180 is controlled by 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 toggle support 130 with respect to tie bar 140 is adjusted, and the distance L between fixed platen 110 and toggle support 130 is adjusted. Further, a plurality of mold thickness adjustment mechanisms may be used in combination.

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

Although the mold clamping device 100 of this embodiment is a horizontal type in which the mold opening/closing direction is the horizontal direction, it may be a vertical type in which the mold opening/closing direction is the vertical direction.

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

<Ejector device>
In the description of the ejector device 200, similarly to the description of the mold clamping device 100, the moving direction of the movable platen 120 when closing the mold (for example, The explanation will be made assuming that the X-axis negative direction) is the rear direction.

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

The ejector rod 210 is arranged in a through hole of the movable platen 120 so as to be able to move forward and backward. The front end of the ejector rod 210 comes into contact with a movable member 830 that is disposed inside the movable mold 820 so as to be able to move forward and backward. The front end of the ejector rod 210 may or may not be connected to the movable member 830.

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

The ejector device 200 performs an ejection process under the control of the control device 700. In the ejecting step, the ejector rod 210 is advanced from the standby position to the ejecting position at a set movement speed, thereby moving the movable member 830 forward and ejecting the molded product. Thereafter, the ejector motor is driven to move the ejector rod 210 backward at a set movement speed, and the movable member 830 is moved back to the original standby position.

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

<Injection device>
In the description of the injection device 300, unlike the description of the mold clamping device 100 and the ejector device 200, the direction of movement of the screw 330 during filling (for example, the negative direction of the X axis) is referred to as the front, and the direction of movement of the screw 330 during metering is (For example, the X-axis positive direction) will be explained as being backward.

The injection device 300 is installed on a slide base 301, and the slide base 301 is arranged to be movable forward and backward relative to the injection device frame 920. The injection device 300 is arranged to be movable forward and backward relative to the mold device 800. The injection device 300 touches the mold device 800 and fills the cavity space 801 in the mold device 800 with the molding material. The injection device 300 includes, for example, a cylinder 310, a nozzle 320, a screw 330, a metering motor 340, an injection motor 350, a pressure detector 360, and the like.

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

The cylinder 310 is divided into a plurality of zones in the axial direction (for example, the X-axis direction) of the cylinder 310. A heater 313 and a temperature detector 314 are provided in each of the plurality of zones. A set temperature is set for each of the plurality of zones, and the control device 700 controls the heater 313 so that the 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 within the cylinder 310 so as to be rotatable and movable back and forth. When the screw 330 is rotated, the molding material is sent forward along the spiral groove of the screw 330. The molding material is gradually melted by heat from the cylinder 310 while being sent forward. As the liquid molding material is sent forward of the screw 330 and accumulated at the front of the cylinder 310, the screw 330 is retracted. Thereafter, when the screw 330 is 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 forward and backward as a backflow prevention valve that prevents the molding material from flowing backward from the front 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 is moved relative to the screw 330 to a closed position (see FIG. 2) where it blocks the flow path of the molding material. fall back. This prevents the molding material accumulated in front of the screw 330 from flowing backward.

On the other hand, when the screw 330 is rotated, the backflow prevention ring 331 is pushed forward by the pressure of the molding material sent forward along the spiral groove of the screw 330, and is moved to an open position where the flow path of the molding material is opened. (see FIG. 1) relative to the screw 330. As a result, the molding material is sent to the front of the screw 330.

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

Note that the injection device 300 may include a drive source that moves the backflow prevention ring 331 forward and backward relative to the screw 330 between an open position and a closed position.

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

The injection motor 350 moves the screw 330 forward and backward. A motion conversion mechanism or the like that converts the rotational motion of the injection motor 350 into linear motion of the screw 330 is provided between the injection motor 350 and the screw 330. The motion conversion mechanism includes, for example, a screw shaft and a screw nut that is threaded onto the screw shaft. A ball, roller, etc. may be provided between the screw shaft and the screw nut. The drive source for advancing and retracting the screw 330 is not limited to the injection motor 350, and may be, for example, a hydraulic cylinder.

Pressure detector 360 detects the force transmitted between injection motor 350 and screw 330. The detected force is converted into pressure by the control device 700. The pressure detector 360 is provided in a force transmission path between the injection motor 350 and the screw 330, and detects the force acting on the pressure detector 360.

Pressure detector 360 sends a signal indicating the detection result to control device 700. The detection results of the pressure detector 360 are used to control and monitor the pressure that the screw 330 receives from the molding material, the back pressure on the screw 330, the pressure that acts on the molding material from the screw 330, and the like.

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

In the metering process, the screw 330 is rotated at a set rotation speed by driving the metering motor 340, and the molding material is sent forward along the spiral groove of the screw 330. Along with this, the molding material is gradually melted. As the liquid molding material is sent forward of the screw 330 and accumulated at the front of the cylinder 310, the screw 330 is retracted. The rotational speed of the screw 330 is detected using, for example, a metering motor encoder 341. Measuring motor encoder 341 detects the rotation of metering motor 340 and sends a signal indicating the detection result to control device 700. Further, the screw rotation speed detector for detecting the rotation speed of the screw 330 is not limited to the metering motor encoder 341, and a general type can be used.

In the metering process, the injection motor 350 may be driven to apply a set back pressure to the screw 330 in order to limit rapid retraction of the screw 330. The back pressure against the screw 330 is detected using, for example, a pressure detector 360. Pressure detector 360 sends a signal indicating the detection result to control device 700. When the screw 330 is retracted 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 measurement start position, a rotational speed switching position, and a measurement completion position are set. These positions are lined up 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 rotation speed is set for each section. The number of rotational speed switching positions may be one or more. The rotational speed switching position does not need to be set. Further, 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 using, for example, an injection motor encoder 351. Injection motor encoder 351 detects rotation of injection motor 350 and sends a signal indicating the detection result to control device 700. When the position of the screw 330 reaches the set position, the filling process is switched to the pressure holding process (so-called V/P switching). The position where V/P switching is performed is also called the V/P switching 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 collectively set as a series of setting conditions. For example, a filling start position (also referred to as an "injection start position"), a moving speed switching position, and a V/P switching position are set. These positions are lined up in this order from the rear to the front, and represent the start and end points of the section in which the moving speed is set. A moving speed is set for each section. There may be one or more moving speed switching positions. The moving speed switching position does not need to be set.

The upper limit value of the pressure of the screw 330 is set for each section in which the moving speed of the screw 330 is set. The pressure of the screw 330 is detected by a pressure detector 360. When the detected value of the pressure detector 360 is less than or equal to the set pressure, the screw 330 is moved forward at the set moving speed. On the other hand, if the detected value of the pressure detector 360 exceeds the set pressure, the screw 330 moves at a slower moving speed than the set moving speed so that the detected value of the pressure detector 360 becomes less than the set pressure in order to protect the mold. will be advanced.

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

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 "holding pressure") is maintained at the set pressure, and the pressure inside the cylinder 310 is maintained. The remaining molding material is pushed toward the mold apparatus 800. Insufficient molding material due to cooling shrinkage within the mold device 800 can be replenished. The holding pressure is detected using a pressure detector 360, for example. Pressure detector 360 sends a signal indicating the detection result to control device 700. The set value of the holding pressure may be changed depending on the elapsed time from the start of the pressure holding process. A plurality of holding pressures and a plurality of holding times for holding the holding pressure in the pressure holding step may be set, and may be set all at once as a series of setting conditions.

In the pressure holding process, the molding material in the cavity space 801 in the mold device 800 is gradually cooled, and when the pressure holding process is completed, the entrance of the cavity space 801 is closed with the solidified molding material. This state is called a gate seal, and backflow of the molding material from the cavity space 801 is prevented. After the pressure holding process, a cooling process is started. In the cooling process, the molding material within the cavity space 801 is solidified. A metering step may be performed during the cooling step to reduce molding cycle time.

Although the injection device 300 of this embodiment is of an in-line screw type, it may also be of a pre-plastic type. A pre-plastic injection device supplies a molding material melted in a plasticizing cylinder to an injection cylinder, and injects the molding material from the injection cylinder into a mold device. Inside the plasticizing cylinder, a screw is arranged so as to be rotatable but not moveable, or a screw is arranged so as to be rotatable and move back and forth. On the other hand, a plunger is arranged within the injection cylinder so that it can move forward and backward.

Moreover, although the injection device 300 of this embodiment is a horizontal type in which the axial direction of the cylinder 310 is horizontal, 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 vertical or horizontal. Similarly, the mold clamping device combined with the horizontal injection device 300 may be horizontal or vertical.

<Mobile device>
In the description of the moving device 400, similarly to the description of the injection device 300, the direction of movement of the screw 330 during filling (for example, the negative direction of the X-axis) is referred to as the front, and the direction of movement of the screw 330 during metering (for example, the positive direction of the X-axis) is referred to as the front. will be explained as backward.

The moving device 400 moves the injection device 300 forward and backward relative to the mold device 800. Furthermore, the moving device 400 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.

Hydraulic pump 410 has a first port 411 and a second port 412. The hydraulic pump 410 is a bidirectionally rotatable pump, and by switching the rotation direction of the motor 420, the hydraulic pump 410 sucks in hydraulic fluid (for example, oil) from one of the first port 411 and the second port 412 and discharges it from the other. to generate hydraulic pressure. Further, the hydraulic pump 410 can also suck the hydraulic fluid from the tank and discharge the hydraulic fluid from either the first port 411 or the second port 412.

Motor 420 operates hydraulic pump 410. The motor 420 drives the hydraulic pump 410 in a rotational direction and rotational torque according to a control signal from the control device 700. 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 partitions 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. Piston rod 433 is fixed relative to 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 injection device 300 is pushed forward by the hydraulic fluid discharged from the first port 411 being supplied to the front chamber 435 via the first flow path 401. The injection device 300 is advanced 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 working fluid supplied from the hydraulic pump 410.

On the other hand, the rear chamber 436 of the hydraulic cylinder 430 is connected to the second port 412 of the hydraulic pump 410 via the second flow path 402 . The injection device 300 is pushed rearward by the hydraulic fluid discharged from the second port 412 being supplied to the rear chamber 436 of the hydraulic cylinder 430 via the second flow path 402. The injection device 300 is moved back, and the nozzle 320 is separated from the fixed mold 810.

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

<Control device>
The control device 700 is composed of, for example, a computer, and includes a CPU (Central Processing Unit) 701, a storage medium 702 such as a memory, an input interface 703, and an output interface 704, as shown in FIGS. The control device 700 performs various controls by causing the CPU 701 to execute programs stored in the storage medium 702. Further, the control device 700 receives a signal from the outside through an input interface 703, and transmits a signal to the outside through an output interface 704.

The control device 700 controls the molded product by repeatedly performing a measuring process, a mold closing process, a pressurizing process, a mold clamping process, a filling process, a pressure holding process, a cooling process, a depressurizing process, a mold opening process, an ejecting process, etc. Manufacture repeatedly. A series of operations for obtaining a molded product, for example, from the start of a metering process to the start of the next metering process, is also called a "shot" or a "molding cycle." The time required for one shot is also called "molding cycle time" or "cycle time."

One molding cycle includes, for example, a measuring process, a mold closing process, a pressure increasing process, a mold clamping process, a filling process, a pressure holding process, a cooling process, a depressurizing process, a mold opening process, and an ejecting process in this order. The order here is the starting order of each step. The filling process, pressure holding process, and cooling process are performed during the mold clamping process. The start of the mold clamping process may coincide with the start of the filling process. The end of the depressurization process coincides with the start of the mold opening process.

Note that a plurality of steps may be performed simultaneously for the purpose of shortening the molding cycle time. For example, the metering step may be performed during the cooling step of the previous molding cycle, or during the clamping step. In this case, the mold closing step may be performed at the beginning of the molding cycle. Also, the filling process may be started during the mold closing process. Also, the ejection process may be started during the mold opening process. If an on-off valve is provided to open and close the flow path of the nozzle 320, the mold opening process may be started during the metering process. This is because even if the mold opening process is started during the metering process, if the on-off valve closes the flow path of the nozzle 320, the molding material will not leak from the nozzle 320.

In addition, one molding cycle includes processes other than the measuring 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. You can.

For example, after the pressure holding process is completed and before the measurement process is started, a pre-measurement suckback process may be performed in which the screw 330 is retreated to a preset measurement start position. The pressure of the molding material accumulated in front of the screw 330 before the start of the metering process can be reduced, and rapid retraction of the screw 330 at the start of the metering process can be prevented.

Further, after the completion of the measurement process and before the start of the filling process, a post-measurement suck-back process may be performed in which the screw 330 is retreated to a preset filling start position (also referred to as "injection start position"). The pressure of the molding material accumulated in front of the screw 330 before the start of the filling process can be reduced, and leakage of the molding material from the nozzle 320 before the start of the filling process can be prevented.

The control device 700 is connected to an operating device 750 that accepts input operations by a user and a display device 760 that displays a display screen. The operating device 750 and the display device 760 may be configured with a touch panel, for example, and may be integrated. The touch panel as the display device 760 displays a display screen under the control of the control device 700. Information such as the settings of the injection molding machine 10 and the current state of the injection molding machine 10 may be displayed on the display screen of the touch panel. Furthermore, the display screen of the touch panel may display input operation units such as buttons and input fields for accepting input operations by the user, for example. The touch panel as the operating device 750 detects an input operation by the user on the display screen, and outputs a signal corresponding to the input operation to the control device 700. As a result, for example, the user can operate the input operation section provided on the display screen while checking the information displayed on the display screen to set the injection molding machine 10 (including inputting setting values), etc. It can be carried out. Further, by the user operating an input operation section provided on the display screen, the injection molding machine 10 can be caused to perform an operation corresponding to the input operation section. Note that the operation of the injection molding machine 10 may be, for example, the operation (including stopping) of the mold clamping device 100, the ejector device 200, the injection device 300, the moving device 400, and the like. Further, the operation of the injection molding machine 10 may be switching of a display screen displayed on a touch panel serving as the display device 760.

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

[Details of ejector device]
Next, details of the ejector device 200 will be described with reference to FIGS. 3 to 5.

FIG. 3 is a front perspective view showing an example of the ejector device 200 according to the present embodiment. FIG. 4 is a rear perspective view showing an example of the ejector device 200 according to the present embodiment. FIG. 5 is a plan sectional view showing an example of the ejector device 200 according to this embodiment.

Ejector device 200 includes an ejector rod 210, a drive mechanism 220, a support 230, a guide bar 240, and a crosshead 250.

Ejector rod 210 (an example of a pressurizing mechanism) is fixed to crosshead 250. The ejector rod 210 is arranged in the through hole 121 of the movable platen 120 so as to be able to move forward and backward. Thereby, by moving the crosshead 250 back and forth in the X direction, the ejector rod 210 can be moved back and forth.

The drive mechanism 220 includes an ejector motor 221 , a motor pulley 222 , a belt 223 , a screw shaft pulley 224 , and a motion conversion mechanism 225 . The motion conversion mechanism 225 includes a screw shaft 226 and a screw nut 227.

Support 230 is fixed to the rear end of movable platen 120. Specifically, the support body 230 is fixed in such a manner that the open end of the hollow portion of the movable platen 120 is closed. The support body 230 rotatably supports one end of the screw shaft 226 via a bearing. The screw shaft 226 is arranged in the hollow part of the movable platen 120 to extend in the X direction between the support body 230 and the front end (end in the positive direction of the X axis) of the movable platen 120, and the other end is , is rotatably supported by a movable platen 120.

The guide bar 240 is disposed inside the movable platen 120 (hollow portion) so as to extend in the X direction between the support body 230 and the front end of the movable platen 120. The guide bar 240 has one end fixed to the support body 230 and the other end fixed to the front end of the movable platen 120.

The crosshead 250 is installed in the hollow part of the movable platen 120 between the support body 230 and the front end of the movable platen 120 so as to be movable in the X direction. A screw shaft 226 and a guide bar 240 pass through the crosshead 250 . Thereby, the crosshead 250 can move in the X direction along the guide bar 240 in the hollow part of the movable platen 120.

Ejector motor 221 (an example of an actuator) is fixed to support 230.

Motor pulley 222 is fixed to the rotating shaft of ejector motor 221.

The belt 223 is provided between the motor pulley 222 and the screw shaft pulley 224 and transmits the rotation of the motor pulley 222 to the screw shaft pulley 224.

The screw shaft pulley 224 is fixed to a screw shaft 226.

The motion conversion mechanism 225 converts the rotational motion of the screw shaft 226 into forward and backward movement of the screw nut 227 in the front-rear direction.

As described above, the screw shaft 226 is rotatably supported by the support body 230 and the front end of the movable platen 120.

The screw nut 227 is screwed into the screw shaft 226 and is fixed to the crosshead 250.

In the ejector device 200, by operating the ejector motor 221, the screw shaft 226 rotates via the motor pulley 222, belt 223, and screw shaft pulley 224. As the screw shaft 226 rotates, the crosshead 250 to which the screw nut 227 is fixed moves in the front-rear direction, allowing the ejector rod 210 to move forward and backward. Thereby, in the ejecting process, the ejector device 200 advances the ejector rod 210, the ejector rod 210 pushes the movable member 830 forward, and as a result, the ejector pin 831 of the movable member 830 can eject the molded product. Further, in the injection process, the ejector device 200 moves the ejector rod 210 forward, and the ejector rod 210 pushes the movable member 830. As a result, a compression core pin 832 (described later) provided on the movable member 830 (see FIGS. 6 and 7) can compress the molding material within the cavity space 801. That is, the ejector device 200 can perform ejector compression.

Ejector motor 221 is controlled by control device 700. Specifically, the ejector motor 221 is provided with an ejector motor encoder 221a that detects its rotation, and the control device 700 may control the ejector motor 221 based on the output of the ejector motor encoder 221a.

[Ejector compression]
Next, details of ejector compression by the ejector device 200 will be described with reference to FIGS. 6 and 7.

FIG. 6 is a side cross-sectional view showing the state of the movable member 830 before the start of ejector compression. FIG. 7 is a side sectional view showing the state of the movable member 830 when the ejector is compressed.

As shown in FIGS. 6 and 7, the movable member 830 (also referred to as "ejector plate") is a plate-shaped member perpendicular to the front-rear direction, and can move freely into and out of the interior (hollow part) of the movable mold 820. It is located.

A guide shaft 834 is provided inside the movable mold 820, and a ball retainer 835 connected to the guide shaft 834 is provided in the movable member 830. Thereby, the movable member 830 is configured to be able to move forward and backward in the axial direction of the guide shaft 834. The number of combinations of guide shaft 834 and ball retainer 835 is, for example, four. Furthermore, the number of combinations of guide shaft 834 and ball retainer 835 may be three or less, or five or more.

A spring 836 is provided between the movable member 830 and a surface (hereinafter simply referred to as "opposed surface") that faces the movable member 830 in the advancing and retreating direction inside the movable mold 820. Thereby, the movable member 830 is configured to be able to retreat while being pressed against the ejector rod 210 by the elastic restoring force of the spring 836.

The front end of the ejector rod 210 can come into contact with the movable member 830 through a through hole provided in the movable mold 820. Further, the ejector rod 210 may be provided with a load cell. The load cell detects the pressure applied to the ejector rod 210, and a signal corresponding to the detection result is taken into the control device 700.

The movable member 830 is provided with an ejector pin 831, a compression core pin 832, an abutment pin 833, and the like.

The ejector pin 831 is a rod-shaped member that extends forward from the plate-shaped movable member 830. Specifically, the ejector pin 831 extends forward from the movable member 830 and passes through a through hole provided in the movable mold 820 (opposed surface). The molding material MM flowing through the runner 803 clings to the front end of the ejector pin 831 and solidifies. The ejector pin 831 moves back and forth together with the movable member 830 and is used to eject the molding material MM solidified by the runner 803.

The compression core pin 832 is a rod-shaped member that extends forward from the plate-shaped movable member 830. Specifically, the compression core pin 832 extends forward from the movable member 830 and passes through a through hole provided in the movable mold 820 (opposed surface). The front end surface of the compression core pin 832 constitutes a part of the wall surface of the cavity space 801. The compression core pin 832 moves forward and backward together with the movable member 830, and is used for ejector compression of the molding material MM, depressurizing the compressed molded product, and ejecting the depressurized molded product.

The abutting pin 833 is a rod-shaped member that extends forward from the plate-shaped movable member 830. Specifically, the abutment pin 833 extends forward from the movable member 830 and passes through a through hole provided in the movable mold 820 (opposed surface). When the movable member 830 is advanced to some extent by the ejector rod 210 during ejector compression, the front end of the abutting pin 833 comes into contact with the end surface of the fixed mold 810 (that is, the mating surface with the movable mold 820). This determines the position of the compression core pin 832 during ejector compression. That is, the abutting pin 833 functions as a mechanical end of the movable member 830 together with the fixed mold 810 during ejector compression. Further, in place of the abutment pin 833, another positioning member functioning as a mechanical end may be provided. For example, a member that restricts the amount of movement of the movable member 830 in the forward direction may be provided between the movable member 830 and the opposing surfaces inside the movable mold 820.

Under the control of the control device 700, the ejector device 200 compresses the molding material MM filled in the cavity space 801 of the mold device 800, and ejects the molded product molded by the ejector compression from the mold device 800. Used for both ejection. The ejector compression of the molding material MM is performed before the molding material MM is completely solidified.

As shown in FIG. 6, in the injection process of the injection device 300, the molding material MM injected from the injection device 300 is transferred to a sprue 802 formed in a fixed mold 810, a runner 803 that branches at the terminal end of the sprue 802, and It reaches the cavity space 801 through a gate 804 provided at the end of the runner 803.

As shown in FIG. 7, in accordance with the filling of the molding material MM, the ejector device 200 moves the ejector rod 210 forward, brings its front end into contact with the movable member 830, and moves the movable member 830 forward. Then, the abutting pin 833 that interlocks with the movable member 830 comes into contact with the fixed mold 810, thereby restricting the forward movement of the ejector rod 210 and the movable member 830, and with the compression core pin 832 positioned, the ejector is compressed. will be held.

[Control method regarding ejector compression]
Next, a method for controlling the ejector device 200 regarding ejector compression by the control device 700 will be described with reference to FIGS. 8 and 9.

<Control method regarding ejector compression according to comparative example>
FIG. 8 is time charts 81 to 83 showing operating conditions during ejector compression of an injection molding machine according to a comparative example. Hereinafter, the same names will be used without reference numerals for the same or corresponding configurations as in the injection molding machine 10 of the present embodiment in the injection molding machine according to the comparative example.

A time chart 81 represents a time change in the pressure in the cavity space of the mold device (hereinafter referred to as "mold internal pressure") during ejector compression of the injection molding machine according to the comparative example.

A time chart 82 represents a change over time of a control command (hereinafter referred to as a "position command") regarding the position of the ejector device in the forward/backward direction, which is output from the control device of the injection molding machine according to the comparative example.

A time chart 83 represents a temporal change in the output torque of the ejector motor of the injection molding machine according to the comparative example.

As shown in the time chart 81, the internal mold pressure of the mold device increases at a relatively high rate of change for a certain period of time from the start of filling the molding material into the cavity space, and reaches the maximum pressure. Thereafter, the mold internal pressure of the mold apparatus gradually decreases as the injection process ends and the molding material hardens.

The control device for the injection molding machine according to the comparative example outputs a position command to the ejector motor to perform position feedback control, and also outputs a torque command to the ejector motor to perform torque feedback control.

As shown in the time chart 82, as a first step, the control device outputs a position command that indicates a predetermined position (for example, the position where the ejector rod abuts the movable member) for a certain period of time. Thereafter, as a second step, the control device shifts to a state in which it outputs a position command that instructs a predetermined position corresponding to the final ejector compression in accordance with the increase in mold internal pressure, and changes that state to a state in which the ejector compression Continue throughout the process. Thereby, the rotational position of the ejector motor is controlled so that the front end of the core compression pin can be stopped at a proper position for performing ejector compression.

Specifically, as a second step, the control device issues a position command corresponding to the same position as the stop position (regular position) of the tip of the core compression pin by the function of the mechanical end of the combination of the abutting pin and the fixed mold. You can output Further, the control device may output a position command corresponding to a position further advanced than the stop position of the tip of the core compression pin due to the function of the mechanical end. This position command may take into account (addition to) a shortfall due to deformation (bending) of the compression core pin, etc., which will be described later, with respect to the normal position. Moreover, in addition to the above-described shortfall with respect to the normal position, a further advance amount may be taken into account (added) to this position command. Thereby, the control device can press the abutment pin against the fixed mold and reliably maintain the tip position of the compression core pin at the normal position.

Further, the control device outputs a torque command to control the ejector motor so that the rotational position of the ejector motor is aligned with the position specified by the position command. The control device outputs a relatively low value torque command for a certain period of time in response to the first stage position command. Thereafter, in response to the second-stage position command, the control device shifts to a state in which a relatively high value torque command is output in accordance with the increase in mold internal pressure, and continues during the ejector compression process. The value of the torque command in the second stage (hereinafter referred to as "torque command value") is extremely high in order to prevent the movable member (compression core pin) from being pushed back and moving from its normal position relative to the maximum value of the mold internal pressure. set to the value.

For example, as described above, the control device controls the ejector motor in response to a position command corresponding to a position further advanced than the stop position of the tip of the core compression pin due to the function of the mechanical end. In this case, the rotational position of the ejector motor cannot actually reach the position specified by the position command. Therefore, the torque command value continues to increase in order to match the actual position of the ejector motor with the position commanded position, and reaches the upper limit value of the output torque of the ejector motor (hereinafter referred to as "torque limit"). If the generated torque command value exceeds the torque limit, the control device limits the actually output torque command value to the torque limit value. Therefore, the control device continues to output the torque command specified by the torque limit value during the core compression process. As a result, as shown in the time chart 83, the output torque of the ejector motor increases stepwise at a relatively large rate of change, and is maintained at a very high, substantially constant value during the ejector compression process.

For example, when the ejector rod is advanced to compress the molding material in the cavity space, the movable part and the transmission part may be elastically deformed by the reaction force (load) caused by the molding material. Specifically, at least some of the belt elongation, movable member deformation, ejector pin deformation, compression core pin deformation, ejector rod deformation, crosshead deformation, screw shaft deformation, etc. may occur. Therefore, the actual tip position of the compression core pin may be set back from the tip position of the compression core pin obtained from the detected value of the ejector motor encoder. Therefore, as described above, the control device of the injection molding machine according to the comparative example outputs a position command corresponding to a position further advanced than the normal position, and as a result, a very high torque (specifically, (torque corresponding to the torque limit) is continuously output. Thereby, displacement of the tip position of the compression core pin due to the reaction force of the molding material can be suppressed. Therefore, the tip position of the compression core pin can be maintained at the normal position by the function of the mechanical end formed by the combination of the abutting pin and the fixed mold.

On the other hand, the ejector motor continues to output extremely high torque. Therefore, for example, there is a possibility that the integrated value of the output current corresponding to the output torque exceeds a predetermined standard, resulting in an overload state. As a result, the injection molding machine according to the comparative example may stop abnormally and its working efficiency may decrease.

<Control method regarding ejector compression according to the present embodiment>
FIG. 9 is time charts 91 to 93 representing operating conditions during ejector compression according to this embodiment.

A time chart 91 represents a temporal change in mold internal pressure within the cavity space 801 of the mold device 800 during ejector compression of the injection molding machine 10 according to the present embodiment.

A time chart 92 represents a temporal change in the position command output from the control device 700 of the injection molding machine 10 according to the present embodiment.

A time chart 93 represents a temporal change in the output torque of the ejector motor 221 of the injection molding machine 10 according to the present embodiment.

The time charts 91 and 92 are the same as the time charts 81 and 82 of the comparative example, so a description thereof will be omitted.

As in the case of the injection molding machine according to the comparative example, the control device 700 outputs a position command to the ejector motor 221 to perform position feedback control, and outputs a torque command to the ejector motor 221 to perform torque feedback control.

The control device 700 outputs a torque command to control the ejector motor 221 so that the rotational position of the ejector motor 221 is aligned with the position specified by the position command. Control device 700 outputs a relatively low value torque command for a certain period of time in response to the first stage position command. Thereafter, in response to the second stage position command, the control device 700 shifts to a state in which a relatively high torque command is output in accordance with the rise in mold pressure, and continues during the ejector compression process. . As in the case of the comparative example, the torque command value in the second stage is a very high value to prevent the movable member 830 (compression core pin 832) from being pushed back and moving from its normal position relative to the maximum value of the mold internal pressure. (hereinafter referred to as "high torque value").

As in the case of the comparative example, the control device 700 controls the ejector motor 221, for example, in response to a position command corresponding to a position further advanced than the stop position of the tip of the core compression pin due to the function of the mechanical end. In this case, the rotational position of the ejector motor 221 cannot actually reach the position specified by the position command. Therefore, the torque command value continues to increase in order to match the actual position of the ejector motor 221 to the position commanded position, and reaches the torque limit (high torque value) of the ejector motor. If the generated torque command value exceeds the torque limit, the control device 700 limits the actually output torque command value to the torque limit value. Therefore, the control device 700 continues to output the torque command specified by the value of the torque limit during the core compression process. As a result, as shown in the time chart 93, the output torque of the ejector motor 221 increases stepwise at a relatively large rate of change to a very high value (normal torque limit of the ejector motor 221).

After setting the torque command value to a high torque value, the control device 700 changes the torque command value in a predetermined control pattern (hereinafter referred to as "control torque pattern") in response to a predetermined trigger. For example, the control device 700 generates a torque command value such that the torque of the ejector motor 221 changes (decreases) after a predetermined delay time (for example, high torque maintenance period P1 described below) has elapsed from a predetermined trigger. You may.

The predetermined trigger may be, for example, the start of a filling process. Further, the predetermined trigger may be, for example, the output torque of the ejector motor 221 reaching a high torque value. Further, the predetermined trigger may be the same as the start trigger of the ejector compression process. Further, the predetermined trigger may be the start of a pressure holding process. Further, the predetermined trigger may be defined based on the position of the injection device 300 (screw 330). Furthermore, the predetermined trigger may be the timing of V/P switching. Further, the predetermined trigger may be reception of an external signal input from outside the injection molding machine 10. The external signal may be output from an external device related to the mold device 800, for example. The external device is, for example, a mold internal pressure sensor installed in the mold device 800. In this case, the external signal corresponding to the predetermined trigger may be output, for example, at the timing when the mold internal pressure of the mold device 800 decreases from its peak.

Specifically, the control device 700 sets the torque command value to a high torque value (first torque example value). After that, during a period P2 from time t2 to time t3 (hereinafter referred to as "torque reduction period"), the control device 700 changes the torque command value from a high torque value to a relatively low value (hereinafter referred to as "low torque value"). (an example of the second torque value) at a constant rate of change over time. Further, the control device 700 may decrease the torque command value at a rate of change that is varied over time. Thereafter, the control device 700 maintains the torque command value at a low torque value during a period P3 from time t3 to the end of the ejector compression process (hereinafter referred to as "low torque maintenance period").

For example, the control device 700 may realize the control torque pattern by varying the torque limit of the ejector motor 221. That is, the control torque pattern may be a control pattern regarding the torque limit of the ejector motor 221 during the core compression process.

The control device 700 maintains the torque limit of the ejector motor 221 at the normal torque limit value during the high torque maintenance period P1 starting from a predetermined trigger. As a result, the torque command value is maintained at a relatively high normal torque limit value (high torque value), and the output torque of the ejector motor 221 is maintained at the normal torque limit value (high torque value) under the control of the control device 700. high torque value).

Furthermore, during the torque reduction period P2, the control device 700 reduces the torque limit of the ejector motor 221 from the normal torque limit value (high torque value) to a relatively low value (low torque value). As a result, the torque command value is maintained at the torque limit value that is varied in a decreasing direction over time, and the torque of the ejector motor 221 is varied from a high torque value to a low torque value under the control of the control device 700. Decrease.

Then, during the low torque maintenance period P3, the control device 700 maintains the torque limit of the ejector motor 221 at a low torque value lower than the normal torque limit value. Thereby, the torque command value is maintained at a low torque value, and the output torque of the ejector motor 221 is maintained at a low torque value under the control of the control device 700.

As a result, as shown in the time chart 93, the output torque of the ejector motor 221 is in a very high state (( high torque value). Therefore, the displacement of the tip position of the compression core pin 832 due to the reaction force of the molding material is suppressed, and the tip position of the compression core pin 832 is maintained at the normal position by the mechanical end function formed by the combination of the abutting pin 833 and the fixed mold 810. be able to.

The output torque of the ejector motor 221 decreases from a high torque value state to a low torque value state between time t2 and time t3. The output torque of the ejector motor 221 is maintained at a low torque value after time t3. This is because, as shown in the time chart 91, the mold internal pressure of the mold device 800 gradually decreases from before time t2, and the output torque required to maintain the position of the compression core pin 832 at the normal position decreases. be. Therefore, the injection molding machine 10 according to the present embodiment can suppress a situation where the integrated value of the output current corresponding to the output torque exceeds a predetermined standard, as in the case of the comparative example.

In this way, the control device 700 controls the control torque pattern of the ejector motor 221 based on the variation pattern of the physical quantity related to the force opposing the drive of the ejector motor 221, specifically, the variation pattern of the mold internal pressure of the mold device 800. Set. As a result, the injection molding machine 10 according to the present embodiment can suppress a situation in which the position of the compression core pin 832 deviates from the normal position, and suppress a decrease in work efficiency due to an overload abnormality of the ejector motor 221. can. That is, the control device 700 controls the torque of the ejector motor 221 based on the variation pattern of the mold internal pressure of the mold device 800, and maintains the position of the ejector device 200 (compression core pin 832).

The control torque pattern may be automatically set, for example, based on the variation pattern of the mold internal pressure of the mold device 800. Specifically, the control torque pattern may be set to have a value equal to or greater than a torque pattern that balances the variation pattern of the mold internal pressure of the mold device 800 over time. Information regarding the variation pattern of the mold internal pressure of the mold device 800 may be obtained in advance through experiments, simulation analysis, etc., and may be registered in advance in an auxiliary storage device or the like inside the control device 700. Further, the information regarding the fluctuation pattern of the mold internal pressure of the mold device 800 may be acquired based on the actual measurement value acquired by the mold internal pressure sensor provided in the mold device 800.

Further, the control torque pattern may be manually set by a user's operation input to the operating device 750, for example, based on the fluctuation pattern of the mold internal pressure of the mold device 800 (see FIG. 10 described later).

Further, the control torque pattern is, for example, a torque pattern that balances the variation pattern of the mold internal pressure of the mold device 800, that is, a torque pattern of the lower limit of allowable torque of the ejector motor 221 for countering the fluctuation pattern of the mold internal pressure of the mold device 800. (hereinafter referred to as "allowable lower limit torque pattern"). Specifically, the control torque pattern may be set by adding a predetermined margin to the allowable lower limit torque pattern. The predetermined margin may be set automatically or may be set manually by the user.

Further, the control torque pattern may be set, for example, based on an allowable upper limit torque pattern (hereinafter referred to as "allowable upper limit torque pattern") for an overload state of the ejector motor 221. Specifically, the control torque pattern may be set, for example, by subtracting a predetermined margin from the allowable upper limit torque pattern. At this time, the predetermined margin is set so that the set control torque pattern does not fall even partially below the allowable lower limit torque pattern. Further, the predetermined margin may be set automatically or may be set manually by the user.

Moreover, the control device 700 may set the control torque pattern of the ejector motor 221 based on the variation pattern of the injection pressure of the injection device 300 instead of or in addition to the variation pattern of the mold internal pressure. This is because the torque required to maintain the compression core pin 832 in the normal position changes depending on the magnitude of the injection pressure of the injection device 300 during the injection process.

[Setting screen related to control torque pattern]
Next, with reference to FIG. 10, a setting screen for setting the control torque pattern of the ejector motor 221 during ejector compression by the control device 700 will be described.

FIG. 10 is a diagram showing an example of a setting screen (setting screen 1000) regarding the control torque pattern displayed on the display device 760.

As shown in FIG. 10, in this example, as described above, the torque command value is maintained at a constant high torque value during the high torque maintenance period P1, and the torque command value is maintained at a constant high torque value during the torque reduction period P2. A control torque pattern is set in which the torque command value decreases from a low torque value at a constant rate of change over time, and in a low torque maintenance period P3, the torque command value is maintained constant at a low torque value.

Setting screen 1000 includes a control torque pattern image 1010 and setting input sections 1020, 1030, 1040, 1050, and 1060.

Control torque pattern image 1010 is an image representing a control torque pattern set on setting screen 1000. Specifically, the control torque pattern image 1010 schematically represents a pattern of changes in the torque command value of the ejector motor 221 over time starting from a predetermined trigger.

The setting input section 1020 is a section into which a high torque value corresponding to the torque command value for the high torque maintenance period P1 is set and input through the operating device 750. The setting input section 1020 includes character information of "high torque setting" and a text box into which a numerical value corresponding to the high torque value is input. In this example, the user can enter the desired high torque value in the text box as a percentage (%) of the maximum torque of the ejector motor 221. In the figure, a high torque value of 90% of the maximum torque of the ejector motor 221 is set and input.

The setting input section 1030 is a section into which a low torque value corresponding to the torque command value for the low torque maintenance period P3 is set and input through the operating device 750. The setting input section 1030 includes character information of "low torque setting" and a text box into which a numerical value corresponding to the low torque value is input. In this example, the user can enter the desired low torque value in the text box as a percentage (%) of the maximum torque of the ejector motor 221. In the figure, a low torque value of 30% of the maximum torque of the ejector motor 221 is set and input.

The setting input section 1040 is a section where the length of the high torque maintenance period P1 is set and input. The starting point of the high torque maintenance period P1 may be, for example, the timing at which a predetermined trigger occurs as described above. The setting input section 1040 includes a text box into which text information of "high torque time" and a numerical value corresponding to the length of the high torque maintenance period P1 are input. In this example, the user can input the desired length of the high torque maintenance period P1, for example, in units of seconds ("sec") based on the timing of a predetermined trigger or the like. In the figure, 2 seconds is set and input as the length of the high torque maintenance period P1.

The setting input section 1050 is a section where the length of the torque reduction period P2 is set and input. The setting input section 1050 includes character information of "reduction time" and a text box into which a numerical value corresponding to the length of the torque reduction period P2 is input. In this example, the user can input the desired length of the torque reduction period P2 in units of seconds ("sec"). In the figure, 10 seconds is set and input as the length of the torque reduction period P2.

The setting input section 1060 is a section where settings are input (selected) to turn on (ON) or turn off (OFF) the control function of the ejector motor 221 based on the control torque pattern set on the setting screen 1000. The setting input section 1060 includes character information of "torque limit function" and a text box in which either ON or OFF is input (selected). Thereby, the user can select for himself whether or not to cause the control device 700 to execute the control function of the ejector motor 221 based on the control torque pattern set on the setting screen 1000 during ejector compression. In the figure, the control function of the ejector motor 221 based on the control torque pattern set on the setting screen 1000 is set to the "on" state.

In this way, the display device 760 displays the setting screen 1000 based on the physical quantity related to the force opposing the drive of the ejector motor 221, that is, the variation pattern of the mold internal pressure of the mold device 800. Thereby, the user can manually set and input the control torque pattern based on the fluctuation pattern of the mold internal pressure of the mold apparatus 800.

Further, in the setting screen 1000, if settings are input that do not match the mold internal pressure pattern of the mold device 800, a message to that effect may be displayed. The content that does not match the mold internal pressure pattern of the mold apparatus 800 is the content that corresponds to a control torque pattern that is lower than the lower limit torque pattern of the ejector motor 221 that can counter the mold internal pressure pattern for at least part of the time change. For example, under the control of the control device 700, the display device 760 displays text boxes of the setting input sections 1020, 1030, 1040, and 1050 in which contents that do not conform to the mold pressure pattern of the mold device 800 are inputted in a different manner than usual. It may be changed to a color (eg, red). Thereby, the display device 760, under the control of the control device 700, can make the user recognize that the content of the current setting input is inappropriate.

Further, in the setting screen 1000, if a setting is input that may cause the ejector motor 221 to become overloaded abnormally, a message to that effect may be displayed. For example, under the control of the control device 700, the display device 760 normally displays text boxes in the setting input sections 1020, 1030, 1040, and 1050 in which contents that may cause the ejector motor 221 to experience an overload abnormality are input. may be changed to a different color (eg, red). Thereby, the display device 760, under the control of the control device 700, can make the user recognize that the content of the current setting input is inappropriate.

Further, in addition to the control torque pattern image 1010, the setting screen 1000 may display an image representing the mold internal pressure pattern of the mold device 800 or the lower limit torque pattern of the ejector motor 221 corresponding to the mold internal pressure pattern. In this case, the graph shape of the control torque pattern of the control torque pattern image 1010 may change depending on the contents of the setting input to the setting input units 1020, 1030, 1040, and 1050. Thereby, the user can set and input an appropriate control torque pattern while checking the mold internal pressure pattern of the mold device 800 and the lower limit torque pattern of the ejector motor 221.

[Transformation, change]
Although the embodiments have been described above, the present disclosure is not limited to specific embodiments, and various modifications and changes can be made within the scope of the gist described in the claims.

For example, in the embodiment described above, a pattern of unevenness may be formed at the tip of the compression core pin 832, and this pattern may be transferred to the molding material by ejector compression. That is, the injection molding machine 10 may perform ejector compression for the purpose of transfer, and depending on the mode, the function of the mechanical end may be omitted. This is because in the case of ejector compression for the purpose of transfer, it may not be necessary to precisely position the tip of the compression core pin 832. In this case, the control device 700 may set the control torque pattern of the ejector motor 221 based on the variation pattern of the mold internal pressure and injection pressure of the mold device 800, as in the above-described embodiment.

For example, if the torque of the ejector motor 221 is relatively small with respect to the mold internal pressure of the mold device 800, the pattern at the tip of the compression core pin 832 may not be transferred well to the molding material due to push back from the molding material. . On the other hand, if the ejector motor 221 continues to output a relatively high torque in order to overcome the pushback from the molding material, there is a possibility that an overload state will occur and the injection molding machine 10 will stop abnormally.

On the other hand, as described above, the control device 700 sets the control torque pattern of the ejector motor 221 to suppress the failure of transfer to the molding material while reducing work efficiency due to overload abnormality of the ejector motor 221. The decrease can be suppressed.

Further, in the above-described embodiments and modified examples, the ejector device 200 has a configuration related to in-mold gate cutting (an example of a pressurizing mechanism), and may perform in-mold gate cutting. In this case, the control device 700 may set the control torque pattern of the ejector motor 221 based on the variation pattern of the physical quantity related to the force opposing the drive of the ejector motor 221, as in the above-described embodiment. The physical quantity related to the force opposing the drive of the ejector motor 221 may be, for example, a reaction force acting on the gate cutting blade edge from the solidified molding material of the gate portion during in-mold gate cutting. While cutting the solidified molding material, a relatively large reaction force acts on the cutting edge, requiring a relatively high torque from the ejector motor 221. However, once cutting is finished, no reaction force acts on the cutting edge. , the relatively high torque of the ejector motor 221 becomes unnecessary.

For example, if the torque of the ejector motor 221 is relatively small with respect to the strength of the solidified molding material, gate cutting may not be realized due to push back from the solidified molding material. On the other hand, if the ejector motor 221 continues to output relatively high torque in order to overcome the pushback from the solidified molding material, an overload condition may occur and the injection molding machine 10 may stop abnormally.

On the other hand, as described above, the control device 700 sets the control torque pattern of the ejector motor 221 to appropriately execute the in-mold gate cut while reducing work efficiency due to overload abnormality of the ejector motor 221. can be suppressed.

Furthermore, in the above-described embodiments and modifications, the injection molding machine 10 may be provided with a core tractor device (an example of a pressurizing device) to perform core compression. In this case, the control device 700 controls the control torque of the actuator (for example, the core tractor motor) that drives the core tractor device based on the variation pattern of the mold internal pressure and injection pressure of the mold device 800, as in the above-described embodiment. You can set a pattern.

For example, if the output torque of the actuator that drives the movable core (an example of a pressure mechanism) of the core tractor device is relatively small with respect to the mold internal pressure of the mold device 800, the tip of the movable core may be pushed back from the molding material. The position of the part may deviate from the appropriate position. On the other hand, if the actuator continues to output relatively high torque in order to overcome the pushback from the molding material, an overload condition may occur and the injection molding machine 10 may stop abnormally.

In contrast, as described above, the control device 700 prevents the situation where the position of the tip of the movable core deviates from the appropriate position by setting the control torque pattern of the actuator that drives the core tractor device (movable core). It is possible to suppress a decrease in work efficiency due to overload abnormality of the actuator.

10 Injection molding machine 100 Mold clamping device 200 Ejector device (pressure device)
210 Ejector rod (pressure mechanism)
221 Ejector motor (actuator)
300 Injection device 400 Movement device 700 Control device 701 CPU
702 Storage medium 703 Input interface 704 Output interface 750 Operating device 760 Display device 800 Mold device 801 Cavity space (cavity)
MM molding material

Claims (1)

A pressurizing device including a pressurizing mechanism that pressurizes a molding material filled in a mold device, and an actuator that drives the pressurizing mechanism;
a control device that controls the pressurizing device;
a display device;
The display device displays a screen for making settings related to control of the torque of the actuator by the control device based on a physical quantity related to a force opposing the drive of the actuator,
On the screen, a first setting input regarding the magnitude of torque in a first control state that maintains the torque of the actuator at a relatively high torque, and a second setting input regarding the magnitude of the torque in a first control state that maintains the torque of the actuator at a relatively low torque. a second setting input regarding the magnitude of the torque in the control state, or a second setting input regarding how to change the torque of the actuator when the torque of the actuator is transferred from the first control state to the second control state. It is possible to input 3 settings.
Injection molding machine.

Images