JP7315441B2 - Injection molding machine - Google Patents

Description

The present disclosure relates to injection molding machines.

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

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

Japanese Patent No. 5850990 Japanese Patent No. 4095013

However, in some cases, for example, the actuator is controlled to press the ejector against a mechanical end (stopper) so that the position of the tip of the movable member does not deviate 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 relatively high torque, the actuator may fall into an overload state, resulting in an abnormal stop of the injection molding machine.

A similar situation can occur during ejector compression for transfer, regardless of the presence or absence of the 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 keep pressing the tip of the movable member against the molding material for a certain amount of time, and the actuator may continue to output relatively high torque.

A similar situation can occur when the molding material is compressed 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 so that the position of the tip of the core does not deviate from the appropriate position due to pushback from the molding material in the cavity, and the actuator may continue to output relatively high torque.

A similar situation can also occur when an ejector cuts the in-mold gate. For example, when cutting an in-mold gate, it is necessary to keep the cutting edge pushed into the gate portion to cut off the gate portion to some extent, and the actuator may continue to output relatively high torque.

Therefore, in view of the above problems, it is an object of the present invention to provide a technology capable of suppressing an overload state of an actuator that drives a pressurizing device that pressurizes a molding material filled in a mold device such as an ejector device or a core tractor device in an injection molding machine.

To achieve the above objectives, in one embodiment of the present disclosure,
a pressurizing device including a pressurizing mechanism for pressurizing the molding material filled in the mold device; and an actuator for driving the pressurizing mechanism;
a control device that controls the pressure device;
a display device;
The display device displays a screen for setting the control pattern of the actuator by the control device based on the variation pattern of the physical quantity related to the force opposing the driving of the actuator,
On the screen, in the control pattern, a first setting input regarding the magnitude of torque in a first control state in which the torque of the actuator is maintained at a relatively high torque, a second setting input regarding the magnitude of torque in a second control state in which the torque of the actuator is maintained at a relatively low torque, or a third setting input regarding how to change the torque when shifting the torque of the actuator from the first control state to the second control state is possible.
An injection molding machine is provided.
Also, in other embodiments of the present disclosure,
a pressurizing device including a pressurizing mechanism for pressurizing the molding material filled in the mold device; and an actuator for driving the pressurizing mechanism;
a control device that controls the pressure device;
a display device;
The display device displays a screen for setting the control device to decrease the torque of the actuator over time,
On the screen, it is possible to input settings regarding how to change the torque when the control device reduces the torque of the actuator over time.
An injection molding machine is provided.
In yet another embodiment of the present disclosure,
a pressurizing device including a pressurizing mechanism for pressurizing the molding material filled in the mold device; and an actuator for driving the pressurizing mechanism;
a control device that controls the pressure device;
a display device;
The display device displays a screen for setting the control pattern of the actuator by the control device based on the variation pattern of the physical quantity related to the force opposing the driving of the actuator,
The control device sets the control pattern regarding the torque of the actuator based on the allowable lower limit torque pattern of the actuator for countering the fluctuation pattern.
An injection molding machine is provided.
In yet another embodiment of the present disclosure,
a pressurizing device including a pressurizing mechanism for pressurizing the molding material filled in the mold device; and an actuator for driving the pressurizing mechanism;
a control device that controls the pressure device;
a display device;
The display device displays a screen for setting the control pattern of the actuator by the control device based on the variation pattern of the physical quantity related to the force opposing the driving of the actuator,
The control device sets the control pattern regarding the torque of the actuator based on the allowable upper limit torque pattern for the overloaded state of the actuator.
An injection molding machine is provided.
In yet another embodiment of the present disclosure,
a pressurizing device including a pressurizing mechanism for pressurizing the molding material filled in the mold device; and an actuator for driving the pressurizing mechanism;
a control device that controls the pressure device;
a display device;
The display device displays a screen for setting the control pattern of the actuator by the control device based on the variation pattern of the physical quantity related to the force opposing the driving of the actuator,
The control device maintains the upper limit of the torque of the actuator at a relatively high first torque value, then decreases the torque from the first torque value to a relatively low second torque value, and sets the control pattern to maintain the second torque value.
An injection molding machine is provided.
In yet another embodiment of the present disclosure,
a pressurizing device including a pressurizing mechanism for pressurizing the molding material filled in the mold device; and an actuator for driving the pressurizing mechanism;
a control device that controls the pressure device;
a display device;
The display device displays a screen for setting the control device to decrease the torque of the actuator over time,
The control device maintains the upper limit of the torque of the actuator at a relatively high first torque value according to the setting input on the screen, and then decreases from the first torque value to a relatively low second torque value and maintains the second torque value.
An injection molding machine is provided.

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

It is a figure which shows an example of an injection molding machine. It is a figure which shows an example of an injection molding machine. It is a front perspective view which shows an example of an ejector apparatus. It is a rear perspective view which shows an example of an ejector apparatus. It is a plane sectional view showing an example of an ejector device. FIG. 4 is a side cross-sectional view showing the state of the movable member before the start of ejector compression; FIG. 5 is a side cross-sectional view showing a state of the movable member when the ejector is compressed; 5 is a time chart showing an operation state during ejector compression of an injection molding machine according to a comparative example; 4 is a time chart showing an operation state during ejector compression of the injection molding machine according to the embodiment; It is a figure which shows an example of the setting screen regarding the control torque pattern displayed on a display apparatus.

Embodiments will be described below with reference to the drawings.

[Configuration of injection molding machine]
<Injection molding machine>
FIG. 1 is a diagram showing a state of an injection molding machine according to one embodiment when mold opening is completed. FIG. 2 is a diagram showing a state of the injection molding machine according to the embodiment at the time of mold clamping. In this specification, the X-axis direction, Y-axis direction and Z-axis direction are directions perpendicular to each other. The X-axis direction and Y-axis direction represent the horizontal direction, and the Z-axis direction represents the vertical direction. When the mold clamping device 100 is of a horizontal type, the X-axis direction is the mold opening/closing direction, and the Y-axis direction is the width direction of the injection molding machine 10 . The Y-axis direction negative side is called the operating side, and the Y-axis direction positive side is called the non-operating 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 by the mold device 800, an injection device 300 that injects a molding material into the mold device 800, a moving device 400 that moves the injection device 300 back and forth with respect to the mold device 800, a control device 700 that controls each component of the injection molding machine 10, and an injection molding machine. and a frame 900 that supports each of the ten components. The frame 900 includes a mold clamping device frame 910 that supports the mold clamping device 100 and an injection device frame 920 that supports the injection device 300 . The mold clamping device frame 910 and the injection device frame 920 are each installed on the floor 2 via leveling adjusters 930 . A control device 700 is arranged in the inner space of the injection device frame 920 . Each component of the injection molding machine 10 will be described below.

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

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

The mold clamping device 100 is of a horizontal type, for example, and the mold opening/closing direction is horizontal. The mold clamping device 100 has a stationary platen 110 , a movable platen 120 , a toggle support 130 , tie bars 140 , a toggle mechanism 150 , a mold clamping motor 160 , a motion converting mechanism 170 and a mold thickness adjusting mechanism 180 .

The fixed platen 110 is fixed with respect to the mold clamping device frame 910 . A stationary mold 810 is attached to the surface of the stationary platen 110 facing the movable platen 120 .

The movable platen 120 is arranged movably 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 laid on the mold clamping device frame 910 . A movable die 820 is attached to the surface of the movable platen 120 facing the stationary platen 110 . By advancing and retreating the movable platen 120 with respect to the fixed platen 110, mold closing, pressure increase, mold clamping, pressure release, and mold opening of the mold device 800 are performed.

The toggle support 130 is spaced apart from the fixed platen 110 and mounted on the mold clamping device frame 910 so as to be movable in the mold opening/closing direction. Also, the toggle support 130 may be arranged movably along a guide laid on the mold clamping device frame 910 . The guides of the toggle support 130 may be common with the guides 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. However, the toggle support 130 may be fixed to the mold clamping device frame 910, and the fixed platen 110 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 stationary platen 110 and the toggle support 130 with a gap L in the mold opening/closing direction. A plurality of (for example, four) tie bars 140 may be used. The multiple tie bars 140 are arranged parallel to the mold opening/closing direction and extend according to the mold clamping force. At least one tie bar 140 may be provided with a tie bar strain detector 141 that detects the strain of the tie bar 140 . Tie-bar distortion detector 141 sends a signal indicating the detection result to control device 700 . The detection result of the tie bar strain detector 141 is used for detection of mold clamping force and the like.

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

The toggle mechanism 150 is arranged 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 is composed of a crosshead 151, a pair of link groups, and the like. A pair of link groups each has a first link 152 and a second link 153 that are connected by a pin or the like so as to be bendable and stretchable. 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. A second link 153 is attached to the crosshead 151 via a third link 154 . When the crosshead 151 advances and retreats with respect to the toggle support 130 , the first link 152 and the second link 153 bend and stretch, and the movable platen 120 advances and retreats 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, although the number of nodes in each link group is five in FIGS.

The mold clamping motor 160 is attached to the toggle support 130 and operates the toggle mechanism 150 . The mold clamping motor 160 advances and retreats the crosshead 151 with respect to the toggle support 130 , thereby bending and stretching the first link 152 and the second link 153 to advance and retreat the movable platen 120 with respect to the toggle support 130 . The mold clamping motor 160 is directly connected to the motion conversion mechanism 170, but may be connected to the motion conversion mechanism 170 via a belt, pulley, or the like.

The motion conversion mechanism 170 converts rotary motion of the mold clamping motor 160 into linear motion of the crosshead 151 . The motion conversion mechanism 170 includes a threaded shaft and a threaded nut that screws onto the threaded shaft. Balls or rollers 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, and the like under the control of the control device 700 .

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

The crosshead position detector for detecting the position of the crosshead 151 and the crosshead moving speed detector for detecting the moving speed of the crosshead 151 are not limited to the mold clamping motor encoder 161, and general ones can be used. Further, the movable platen position detector for detecting the position of the movable platen 120 and the movable platen moving speed detector for detecting the moving speed of the movable platen 120 are not limited to the mold clamping motor encoder 161, and general ones can be used.

In the pressurization step, 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 a 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 pressurizing 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 a liquid molding material. A molded product is obtained by solidifying the filled molding material.

The number of cavity spaces 801 may be one or plural. In the latter case, multiple moldings are obtained simultaneously. The insert material may be arranged in part of the cavity space 801 and the other part of the cavity space 801 may be filled with the molding material. A molded product in which the insert material and the molding material are integrated is obtained.

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

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

The set conditions in the mold closing process, the pressurizing process, and the mold clamping process are collectively set as a series of set conditions. For example, the movement 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 pressurizing process are collectively set as a series of setting conditions. 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 to the front side, and represent the start point and end point of the section in which the movement speed is set. A moving speed is set for each section. The moving speed switching position may be one or plural. The moving speed switching position does not have to be set. Only one of the mold clamping position and the mold clamping force may be set.

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

Incidentally, instead of the moving speed and position of the crosshead 151, the moving speed and position of the movable platen 120 may be set. Also, the mold clamping force may be set instead of the position of the crosshead (for example, mold clamping position) or the position of the movable platen.

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 toggle factor. The toggle magnification changes according to the angle θ formed between the first link 152 and the second link 153 (hereinafter also referred to as “link angle θ”). The link angle θ is obtained from the position of the crosshead 151 . When the link angle θ is 180°, the toggle magnification becomes maximum.

When the thickness of the mold apparatus 800 changes due to replacement of the mold apparatus 800 or temperature change of the mold apparatus 800, the mold thickness is adjusted so that a predetermined mold clamping force can be obtained during mold clamping. In the mold thickness adjustment, 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 when the movable mold 820 touches the fixed mold 810, for example.

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

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

The rotational driving force transmission section 185 is configured by, for example, a gear. In this case, a passive gear is formed on the outer periphery of each screw nut 182, a driving gear is attached to the output shaft of the mold thickness adjusting motor 183, and an intermediate gear meshing with the plurality of passive gears and the driving gear is rotatably held at the center of the toggle support 130. Also, the rotational driving force transmission section 185 may be configured by a belt, a pulley, or the like instead of the gear.

The operation of the mold thickness adjusting mechanism 180 is controlled by the controller 700 . The control device 700 drives the mold thickness adjusting 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 stationary platen 110 and toggle support 130 is adjusted. Also, a plurality of mold thickness adjusting mechanisms may be used in combination.

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

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

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

<Ejector device>
In the description of the ejector device 200, as in the description of the mold clamping device 100, the moving direction of the movable platen 120 when the mold is closed (e.g., the X-axis positive direction) is defined as the front, and the moving direction of the movable platen 120 when the mold is opened (e.g., the X-axis negative direction) is defined as the rear.

An ejector device 200 (an example of a pressure device) is attached to the movable platen 120 and advances and retreats together with the movable platen 120 . The ejector device 200 has an ejector rod 210 that ejects a molded product from the mold device 800 and a drive mechanism 220 that moves the ejector rod 210 in the moving direction of the movable platen 120 (X-axis direction).

The ejector rod 210 is disposed in a through hole of the movable platen 120 so as to be able to move back and forth. A front end portion of the ejector rod 210 contacts a movable member 830 that is arranged to move back and forth inside the movable mold 820 . The front end of ejector rod 210 may or may not be connected to movable member 830 .

The drive mechanism 220 has, for example, an ejector motor and a motion conversion mechanism that converts rotary motion of the ejector motor into linear motion of the ejector rod 210 . The motion conversion mechanism includes a threaded shaft and a threaded nut that screws onto the threaded shaft. Balls or rollers 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 ejection step, the ejector rod 210 is moved forward from the standby position to the ejection position at the set moving speed, thereby advancing the movable member 830 and ejecting the molded product. After that, the ejector motor is driven to retract the ejector rod 210 at the set movement speed, and the movable member 830 is retracted 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 rotation of the ejector motor and sends a signal indicating the detection result to the control device 700 . Also, the ejector rod position detector for detecting the position of the ejector rod 210 and the ejector rod moving speed detector for detecting the moving speed of the ejector rod 210 are not limited to ejector motor encoders, 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 description of the ejector device 200, the direction of movement of the screw 330 during filling (e.g., the negative direction of the X axis) is defined as the front, and the direction of movement of the screw 330 during weighing (e.g., the positive direction of the X axis) is defined as the rear.

The injection device 300 is installed on a slide base 301 , and the slide base 301 is arranged to move back and forth with respect to the injection device frame 920 . The injection device 300 is arranged to move back and forth with respect to the mold device 800 . The injection device 300 touches the mold device 800 and fills the cavity space 801 in the mold device 800 with the molding material. The injection device 300 has, 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 inside from the supply port 311 . The molding material includes, for example, resin. The molding material is formed into, for example, a pellet shape and supplied to the supply port 311 in a solid state. A supply port 311 is formed in the rear portion of the cylinder 310 . A cooler 312 such as a water-cooled cylinder is provided on the outer circumference 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 ahead of the cooler 312 .

Cylinder 310 is divided into a plurality of zones in the axial direction of cylinder 310 (for example, the X-axis direction). 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 controller 700 controls the heater 313 so that the temperature detected by the temperature detector 314 becomes the set temperature.

A nozzle 320 is provided at the front end of the cylinder 310 and pressed against the mold device 800 . A heater 313 and a temperature detector 314 are provided around the nozzle 320 . The controller 700 controls the heater 313 so that the detected temperature of the nozzle 320 becomes the set temperature.

The screw 330 is arranged in the cylinder 310 so as to be rotatable and advanceable. When the screw 330 is rotated, the molding material is sent forward along the helical groove of the screw 330 . The molding material is gradually melted by the heat from the cylinder 310 while being fed forward. The screw 330 is retracted as liquid molding material is fed forward of the screw 330 and accumulated at the front of the cylinder 310 . After that, when the screw 330 is advanced, the liquid molding material accumulated in front of the screw 330 is injected from the nozzle 320 and filled in the mold device 800 .

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

When the screw 330 is advanced, the anti-backflow ring 331 is pushed backward by the pressure of the molding material in front of the screw 330, and retreats relative to the screw 330 to a closed position (see FIG. 2) that closes the flow path of the molding material. 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 anti-backflow ring 331 is pushed forward by the pressure of the molding material sent forward along the helical groove of the screw 330, and advances relative to the screw 330 to an open position (see FIG. 1) where the flow path of the molding material is opened. Thereby, the molding material is sent forward of the screw 330 .

The anti-backflow 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 .

The injection device 300 may have a drive source for advancing and retracting the anti-backflow ring 331 with respect to the screw 330 between the open position and the 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 advances and retreats the screw 330 . Between the injection motor 350 and the screw 330, a motion conversion mechanism or the like that converts the rotary motion of the injection motor 350 into the linear motion of the screw 330 is provided. The motion conversion mechanism has, for example, a screw shaft and a screw nut that screws onto the screw shaft. Balls, rollers, or the like may be provided between the screw shaft and the screw nut. The drive source for advancing and retreating 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 the 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 controller 700 . The detection result of the pressure detector 360 is used for controlling and monitoring the pressure that the screw 330 receives from the molding material, the back pressure against the screw 330, the pressure that the screw 330 acts on the molding material, and the like.

The injection device 300 performs a weighing process, a filling process, a holding pressure process, etc. under the control of the control device 700 . The filling process and the holding pressure process may collectively be called an injection process.

In the weighing process, the weighing motor 340 is driven to rotate the screw 330 at a set rotation speed, and the molding material is fed forward along the helical groove of the screw 330 . Along with this, the molding material is gradually melted. The screw 330 is retracted as liquid molding material is fed forward of the screw 330 and accumulated at the front of the cylinder 310 . The rotation speed of the screw 330 is detected using a metering motor encoder 341, for example. Weighing motor encoder 341 detects the rotation of weighing motor 340 and sends a signal indicating the detection result to control device 700 . Moreover, 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 one can be used.

During the metering process, the injection motor 350 may be driven to apply a set back pressure to the screw 330 to limit its rapid retraction. The back pressure on screw 330 is detected using pressure detector 360, for example. Pressure detector 360 sends a signal indicating the detection result to controller 700 . The metering process is completed 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 position and rotation speed of the screw 330 in the metering process are collectively set as a series of setting conditions. For example, a weighing start position, rotation speed switching position, and weighing completion position are set. These positions are arranged in this order from the front side to the rear side, and represent the start point and end point of the section in which the rotational speed is set. A rotation speed is set for each section. The rotational speed switching position may be one or plural. The rotation speed switching position does not have to be set. Also, the back pressure is set for each section.

In the filling step, 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 an injection motor encoder 351, for example. The injection motor encoder 351 detects rotation of the injection motor 350 and sends a signal indicating the detection result to the control device 700 . When the position of the screw 330 reaches the set position, switching from the filling process to the holding pressure process (so-called V/P switching) is performed. The position at which V/P switching takes place is also called the V/P switching position. The set moving speed of the screw 330 may be changed according to the position of the screw 330, time, and the like.

The position and moving 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 called an “injection start position”), a moving speed switching position, and a V/P switching position are set. These positions are arranged in this order from the rear side to the front side, and represent the start point and end point of the section for which the movement speed is set. A moving speed is set for each section. The moving speed switching position may be one or plural. The moving speed switching position does not have to be set.

An 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 screw 330 is detected by pressure detector 360 . When the detected value of the pressure detector 360 is equal to or less than the set pressure, the screw 330 is advanced at the set moving speed. On the other hand, when the detected value of the pressure detector 360 exceeds the set pressure, the screw 330 is advanced at a slower moving speed than the set moving speed so that the detected value of the pressure detector 360 is equal to or less than the set pressure for the purpose of mold protection.

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 slowly advanced or slowly retracted. Moreover, the screw position detector for detecting the position of the screw 330 and the screw moving speed detector for detecting the moving speed of the screw 330 are not limited to the injection motor encoder 351, and general ones can be used.

In the holding pressure process, the injection motor 350 is driven to push the screw 330 forward, the pressure of the molding material at the front end of the screw 330 (hereinafter also referred to as "holding pressure") is maintained at the set pressure, and the molding material remaining in the cylinder 310 is pushed toward the mold device 800. A shortage of molding material due to cooling shrinkage in the mold apparatus 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 controller 700 . The set value of the holding pressure may be changed according to the elapsed time from the start of the holding pressure process. A plurality of holding pressures and holding times for holding the holding pressure in the holding pressure step may be set respectively, and may be collectively set as a series of setting conditions.

In the holding pressure process, the molding material in the cavity space 801 inside the mold apparatus 800 is gradually cooled, and when the holding pressure 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 prevents the molding material from flowing back from the cavity space 801 . After the holding pressure process, the cooling process is started. In the cooling process, the molding material inside the cavity space 801 is solidified. A metering step may be performed during the cooling step for the purpose of shortening the molding cycle time.

Although the injection device 300 of this embodiment is of the in-line screw type, it may be of a pre-plastic type or the like. A pre-plastic injection apparatus supplies molding material melted in a plasticizing cylinder to an injection cylinder, and injects the molding material from the injection cylinder into a mold apparatus. Inside the plasticizing cylinder, a screw is arranged to be rotatable and non-retractable, or a screw is arranged to be rotatable and reciprocal. On the other hand, a plunger is arranged in the injection cylinder so that it can move back and forth.

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

<Moving device>
In the description of the moving device 400, as in the description of the injection device 300, the direction of movement of the screw 330 during filling (e.g., the negative direction of the X axis) is defined as the front, and the direction of movement of the screw 330 during weighing (e.g., the positive direction of the X axis) is defined as the rear.

The moving device 400 moves the injection device 300 forward and backward with respect to the mold device 800 . Further, the moving device 400 presses the nozzle 320 against the mold device 800 to generate 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 . Hydraulic pump 410 is a bi-directional rotatable pump, and by switching the rotational direction of motor 420, hydraulic fluid (e.g., oil) is sucked from one of first port 411 and second port 412 and discharged from the other to generate hydraulic pressure. In addition, 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 . Motor 420 drives hydraulic pump 410 with a rotation direction and a rotation torque according to a control signal from control device 700 . Motor 420 may be an electric motor or may be an electric servomotor.

The hydraulic cylinder 430 has a cylinder body 431 , a piston 432 and a piston rod 433 . The cylinder body 431 is fixed with respect 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 stationary platen 110 .

The front chamber 435 of the hydraulic cylinder 430 is connected to the first port 411 of the hydraulic pump 410 via the first flow path 401 . The hydraulic fluid discharged from the first port 411 is supplied to the front chamber 435 through the first flow path 401, thereby pushing the injection device 300 forward. The injection device 300 is advanced and the nozzle 320 is pressed against the stationary mold 810 . The front chamber 435 functions as a pressure chamber that generates nozzle touch pressure of the nozzle 320 by pressure of hydraulic 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 hydraulic fluid discharged from the second port 412 is supplied to the rear chamber 436 of the hydraulic cylinder 430 through the second flow path 402, thereby pushing the injection device 300 rearward. The injection device 300 is retracted and the nozzle 320 is separated from the stationary mold 810 .

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

<Control device>
The control device 700 is composed of a computer, for example, and has 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 . The control device 700 also receives signals from the outside through an input interface 703 and transmits signals to the outside through an output interface 704 .

The control device 700 repeatedly performs a weighing process, a mold closing process, a pressurizing process, a mold clamping process, a filling process, a holding pressure process, a cooling process, a depressurizing process, a mold opening process, and an ejecting process, thereby repeatedly manufacturing molded products. A series of operations for obtaining a molded product, for example, operations from the start of a weighing process to the start of the next weighing process, are 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 has, for example, a weighing process, a mold closing process, a pressure increasing process, a mold clamping process, a filling process, a holding pressure process, a cooling process, a depressurizing process, a mold opening process, and an ejecting process in this order. The order here is the order of the start of each step. The filling process, holding pressure process, and cooling process are performed during the clamping process. The start of the 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.

A plurality of steps may be performed simultaneously for the purpose of shortening the molding cycle time. For example, the metering step may occur during the cooling step of the previous molding cycle and may occur during the clamping step. In this case, the mold closing process may be performed at the beginning of the molding cycle. The filling process may also be initiated during the mold closing process. Also, the ejecting process may be initiated during the mold opening process. If an on-off valve for opening and closing the flow path of the nozzle 320 is provided, the mold opening process may be initiated during the metering process. This is because the molding material does not leak from the nozzle 320 as long as the on-off valve closes the flow path of the nozzle 320 even if the mold opening process is started during the metering process.

One molding cycle may include processes other than the weighing process, mold closing process, pressurizing process, mold clamping process, filling process, holding pressure process, cooling process, depressurizing process, mold opening process, and ejecting process.

For example, after the pressure holding process is completed and before the measuring process is started, a pre-measuring suck-back process for retracting the screw 330 to a preset measuring start position may be performed. It is possible to reduce the pressure of the molding material accumulated in front of the screw 330 before the start of the metering process, and to prevent the screw 330 from abrupt retraction at the start of the metering process.

After the weighing process is completed and before the filling process starts, a post-weighing suck-back process may be performed in which the screw 330 is retracted to a preset filling start position (also referred to as an “injection start position”). The pressure of the molding material accumulated in front of the screw 330 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 operation device 750 that receives an input operation by a user and a display device 760 that displays a display screen. The operation device 750 and the display device 760 may be configured by, for example, a touch panel and integrated. A touch panel as display device 760 displays a display screen under the control of 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. Further, the display screen of the touch panel may display, for example, an input operation section such as a button for receiving an input operation by the user, an input field, or the like. A touch panel as the operation device 750 detects an input operation on the display screen by the user and outputs a signal corresponding to the input operation to the control device 700 . As a result, for example, the user can operate the input operation unit provided on the display screen while confirming the information displayed on the display screen to set the injection molding machine 10 (including input of set values). Further, by operating the input operation section provided on the display screen, the user can cause the injection molding machine 10 to operate corresponding to the input operation section. 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 as the display device 760, or the like.

Although the operating device 750 and the display device 760 of the present embodiment have been described as integrated as a touch panel, they may be provided independently. Also, 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.

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

The 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 pressure mechanism) is fixed to crosshead 250 . The ejector rod 210 is arranged to move back and forth in the through hole 121 of the movable platen 120 . As a result, the ejector rod 210 can be advanced and retreated by advancing and retreating the crosshead 250 in the X direction.

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 . Motion converting mechanism 225 includes a threaded shaft 226 and a threaded nut 227 .

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

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

The crosshead 250 is installed in the hollow portion of the movable platen 120 between the support 230 and the front end portion 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 portion of the movable platen 120 .

An ejector motor 221 (an example of an actuator) is fixed to the support 230 .

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

Belt 223 is provided between motor pulley 222 and screw shaft pulley 224 to transmit rotation of motor pulley 222 to screw shaft pulley 224 .

A 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 .

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

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

The ejector device 200 rotates the screw shaft 226 via the motor pulley 222 , the belt 223 and the screw shaft pulley 224 by operating the ejector motor 221 . By rotating the threaded shaft 226, the crosshead 250 to which the threaded nut 227 is fixed moves in the front-rear direction, and the ejector rod 210 can be advanced or retracted. As a result, the ejector device 200 advances the ejector rod 210 in the ejecting process, 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. In the injection process, the ejector device 200 advances the ejector rod 210, the ejector rod 210 pushes the movable member 830, and as a result, a later-described compression core pin 832 (see FIGS. 6 and 7) provided on the movable member 830 can compress the molding material in 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.

FIG. 6 is a side 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 an “ejector plate”) is a plate-shaped member perpendicular to the front-rear direction, and is disposed inside (hollow portion) of the movable mold 820 so as to be movable back and forth.

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 movable back and forth in the axial direction of the guide shaft 834 . The number of combinations of guide shafts 834 and ball retainers 835 is, for example, four. Also, the number of combinations of the guide shafts 834 and the ball retainers 835 may be three or less, or may be five or more.

A spring 836 is provided between the movable member 830 and a facing surface of the movable member 830 inside the movable mold 820 in the advancing/retreating direction (hereinafter simply referred to as “facing surface”). 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 . Also, the ejector rod 210 may be provided with a load cell. The load cell detects pressure applied to the ejector rod 210 and a signal corresponding to the detection result is taken into the controller 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 extending 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 (opposing 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 advances and retreats together with the movable member 830 and is used to eject the molding material MM solidified on the runner 803 .

The compression core pin 832 is a rod-shaped member extending 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 (facing surface). A front end surface of the compression core pin 832 forms part of the wall surface of the cavity space 801 . The compression core pin 832 advances and retreats together with the movable member 830, and is used for ejector compression of the molding material MM, depressurization of the compressed molded product, and ejection of the depressurized molded product.

The abutment pin 833 is a rod-shaped member extending 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 (opposing surface). When the ejector rod 210 advances the movable member 830 to some extent during ejector compression, the front end of the abutment pin 833 contacts 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 in ejector compression. In other words, the abutment pin 833 functions as a mechanical end of the movable member 830 together with the stationary mold 810 when the ejector is compressed. Also, instead of the abutment pin 833, another positioning member that functions as a mechanical end may be provided. For example, a member that regulates the amount of movement of the movable member 830 in the forward direction may be provided between the movable member 830 and the facing surface inside the movable mold 820 .

The ejector device 200 is used for both ejector compression of the molding material MM filled in the cavity space 801 of the mold device 800 and ejection of the molded article molded by the ejector compression from the mold device 800 under the control of the control device 700. 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 reaches the cavity space 801 through a sprue 802 formed in a fixed mold 810, a runner 803 branching from the end of the sprue 802, and a gate 804 provided at the end of the runner 803.

As shown in FIG. 7, the ejector device 200 advances the ejector rod 210 in accordance with the filling of the molding material MM, brings the front end portion thereof into contact with the movable member 830, and advances the movable member 830. As shown in FIG. Then, the abutment pin 833 interlocking with the movable member 830 abuts against the fixed mold 810, restricting the forward movement of the ejector rod 210 and the movable member 830, and ejector compression is performed in a state in which the compression core pin 832 is positioned.

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

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

A time chart 81 represents the change over time of the pressure in the cavity space of the mold device (hereinafter referred to as “internal pressure”) during compression of the ejector 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") relating to the position of the ejector device in the advancing/retreating direction, which is output from the control device of the injection molding machine according to the comparative example.

A time chart 83 represents temporal changes 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 rises at a relatively high rate of change for a certain amount of time from the start of filling the cavity space with the molding material, and reaches the maximum pressure. After that, the pressure inside the mold device gradually decreases as the injection process ends and the curing of the molding material progresses.

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

As shown in a time chart 82, the control device outputs a position command for a certain period of time to indicate a predetermined position (for example, the position where the ejector rod abuts against the movable member) as the first stage. After that, as the second step, the control device shifts to a state of outputting a position command indicating a predetermined position corresponding to the final ejector compression so as to match the rise of the mold internal pressure, and continues this state during the process of ejector compression. Thereby, the rotational position of the ejector motor is controlled so that the front end of the core compression pin can be stopped at the proper position for ejector compression.

Specifically, as the second step, the control device may output 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 abutment pin and the fixed mold. Further, the control device may output a position command corresponding to a position further forward than the stop position of the tip portion of the core compression pin due to the function of the mechanical end. This position command may take into consideration (add) a shortage due to deformation (deflection) of a compression core pin or the like, which will be described later, with respect to the normal position. In addition to the above-described shortfall, the position command may take into account (add) a further advance amount with respect to the normal position. Thereby, the control device can press the abutment pin against the stationary mold and reliably maintain the tip position of the compression core pin at the regular position.

Further, the control device outputs a torque command to match the rotational position of the ejector motor to the position defined by the position command, and controls the ejector motor. The control device outputs a torque command of a relatively low value for a certain period of time in response to the position command of the first stage. After that, the control device shifts to a state of outputting a relatively high value torque command in accordance with the second stage position command so as to match the rise of the mold internal pressure, and continues during the process of ejector compression. The second stage torque command value (hereinafter referred to as “torque command value”) is set to a very high value with respect to the maximum mold pressure so that the movable member (compression core pin) is pushed back and does not move from its normal position.

For example, as described above, the control device controls the ejector motor in accordance with a position command corresponding to a position further forward than the stop position of the tip portion 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 rise in order to align the actual position of the ejector motor with the position of the position command, and reaches the upper limit value (hereinafter referred to as "torque limit") of the output torque of the ejector motor. When the torque command value to be generated exceeds the torque limit, the control device limits the torque command value to be actually output to the value of the torque limit. Therefore, the control device continues to output the torque command defined by the torque limit value during the core compression process. As a result, as shown in a 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 reaction force (load) of the molding material may elastically deform the movable portion and the transmission portion. Specifically, at least part of belt elongation, movable member deformation, ejector pin deformation, compression core pin deformation, ejector rod deformation, crosshead deformation, screw shaft deformation, and the like may occur. Therefore, the actual tip position of the compression core pin may retreat 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 forward than the normal position, and as a result, the ejector motor continues to output a very high torque (specifically, torque corresponding to the torque limit). 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 regular position by the mechanical end function of the combination of the abutment pin and the fixed die.

On the other hand, the ejector motor continues to output a very high torque. Therefore, for example, there is a possibility that the integrated value of the output current corresponding to the output torque will exceed a predetermined reference and fall into an overload state. As a result, there is a possibility that the injection molding machine according to the comparative example will stop abnormally and its working efficiency will decrease.

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

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

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

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

The time charts 91 and 92 are the same as the time charts 81 and 82 of the comparative example, so description thereof is 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 controls the ejector motor 221 by outputting a torque command so that the rotational position of the ejector motor 221 is adjusted to the position defined by the position command. The control device 700 outputs a torque command of a relatively low value for a certain period of time in response to the position command of the first stage. After that, the control device 700 shifts to a state of outputting a relatively high value torque command in accordance with the rise of the mold internal pressure according to the position command of the second step, and continues it during the process of ejector compression. As in the case of the comparative example, the torque command value in the second stage is set to a very high value (hereinafter referred to as "high torque value") so that the movable member 830 (compression core pin 832) is pushed back and does not move from the normal position with respect to the maximum value of the internal mold pressure.

As in the comparative example, the control device 700 controls the ejector motor 221 according to a position command corresponding to a position further forward than the stop position of the tip of the core compression pin by 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 rise in order to align the actual position of the ejector motor 221 with the position of the position command, and reaches the torque limit (high torque value) of the ejector motor. When the torque command value to be generated exceeds the torque limit, control device 700 limits the torque command value to be actually output to the value of the torque limit. Therefore, the control device 700 continues to output the torque command defined by the torque limit value during the core compression process. As a result, as shown in a 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 according to a predetermined control pattern (hereinafter referred to as "control torque pattern") in response to a predetermined trigger. For example, the control device 700 may generate a torque command value such that the torque of the ejector motor 221 changes (decreases) after a predetermined delay time (for example, a high torque maintenance period P1 described later) has elapsed from a predetermined trigger.

A predetermined trigger may be, for example, the start of a filling process. Also, the predetermined trigger may be, for example, reaching a high torque value of the output torque of the ejector motor 221 . The predetermined trigger may also be the same as the start trigger for the ejector compression process. Also, the predetermined trigger may be the start of a pressure holding process. Also, the predetermined trigger may be defined based on the position of the injection device 300 (screw 330). Also, the predetermined trigger may be the timing of V/P switching. Also, 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 apparatus 800, for example. The external device is, for example, a mold internal pressure sensor installed in the mold apparatus 800 . In this case, the external signal corresponding to the predetermined trigger may be output, for example, at the timing when the internal mold pressure of the mold apparatus 800 has decreased from the peak.

Specifically, control device 700 maintains the torque command value at a high torque value (an example of a first torque value) during a period P1 from time t1 to time t2 corresponding to a predetermined trigger (hereinafter referred to as "high torque maintenance period"). After that, during a period P2 from time t2 to time t3 (hereinafter referred to as "torque decrease period"), control device 700 decreases the torque command value from the high torque value to a relatively low value (hereinafter referred to as "low torque value") (an example of a second torque value) at a constant rate of change over time. In addition, control device 700 may decrease the torque command value at a rate of change that is variable over time. Thereafter, the control device 700 maintains the torque command value at the low torque value for 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 related to 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.

Further, 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) during the torque decrease period P2. As a result, the torque command value is maintained at the torque limit value that is varied in the decreasing direction over time, and the torque of the ejector motor 221 decreases from a high torque value to a low torque value under the control of the control device 700.

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

As a result, as shown in a time chart 93, the output torque of the ejector motor 221 is maintained in a very high state (high torque value state) from time t1 to time t2, which corresponds to a state in which the internal pressure of the mold device 800 is relatively high. Therefore, 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 can be maintained at a regular position by the mechanical end function of the combination of the abutment pin 833 and the fixed mold 810.

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

In this way, the control device 700 sets 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 internal mold pressure of the mold device 800. As a result, the injection molding machine 10 according to the present embodiment can prevent the compression core pin 832 from being displaced from its normal position, and can prevent the work efficiency from being lowered due to the overload abnormality of the ejector motor 221 . That is, the control device 700 controls the torque of the ejector motor 221 based on the fluctuation pattern of the mold internal pressure of the mold device 800 to hold the position of the ejector device 200 (compression core pin 832).

The control torque pattern may be automatically set based on, for example, the fluctuation pattern of the internal mold pressure of the mold apparatus 800 . Specifically, the control torque pattern may be set to have a value equal to or greater than the torque pattern that balances the variation pattern of the internal mold pressure of the mold apparatus 800 over time. Information about the variation pattern of the internal mold pressure of the mold apparatus 800 may be acquired in advance through, for example, 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 about the fluctuation pattern of the mold internal pressure of the mold apparatus 800 may be obtained based on the actual measurement value obtained by the mold internal pressure sensor provided in the mold apparatus 800 .

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

Further, the control torque pattern may be set based on, for example, a torque pattern that balances with the fluctuation pattern of the mold internal pressure of the mold apparatus 800, i.e., based on the allowable lower limit torque pattern of the ejector motor 221 for countering the fluctuation pattern of the mold internal pressure of the mold apparatus 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 manually by the user.

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

Further, 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 internal mold pressure. This is because the torque required to maintain the compression core pin 832 at its proper position changes depending on the magnitude of the injection pressure of the injection device 300 during the injection process.

[Control torque pattern setting screen]
Next, 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 with reference to FIG.

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

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

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

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

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

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

A setting input section 1040 is a section for setting and inputting the length of the high torque maintenance period P1. 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 portion 1040 includes text information of "high torque time" and a text box for inputting a numerical value corresponding to the length of the high torque maintenance period P1. In this example, the user can input the desired length of the high torque maintenance period P1 in units of seconds (“sec”) based on the timing of a predetermined trigger or the like. In the drawing, 2 seconds is set and input as the length of the high torque maintenance period P1.

A setting input section 1050 is a section for setting and inputting the length of the torque decrease period P2. The setting input section 1050 includes text information of "decrease time" and a text box for inputting a numerical value corresponding to the length of the torque decrease period P2. In this example, the user can enter the length of the torque reduction period P2 that they want to set in seconds ("sec"). In the drawing, 10 seconds is set and input as the length of the torque reduction period P2.

The setting input section 1060 is a section for setting input (selection) of ON/OFF of the control function of the ejector motor 221 based on the control torque pattern set on the setting screen 1000 . The setting input portion 1060 includes text information of "torque limiting function" and a text box for inputting (selecting) either ON/OFF. Thereby, the user can select by himself/herself 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 when the ejector is compressed. In the drawing, the control function of the ejector motor 221 based on the control torque pattern set on the setting screen 1000 is set to "on".

In this manner, the display device 760 displays the setting screen 1000 based on the physical quantity related to the force that opposes 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 internal mold pressure of the mold apparatus 800 .

Further, in the setting screen 1000, when a setting input is made that does not match the mold internal pressure pattern of the mold apparatus 800, a message to that effect may be displayed. Contents that do not match the mold internal pressure pattern of the mold apparatus 800 correspond to control torque patterns that fall below the lower limit torque pattern of the ejector motor 221 capable of resisting the mold internal pressure pattern in at least part of the time change. For example, under the control of the control device 700, the display device 760 may change the text boxes of the setting input sections 1020, 1030, 1040, and 1050, in which content that does not match the internal mold pressure pattern of the mold device 800, is changed to a different color (for example, red). Thereby, the display device 760 can make the user recognize that the content of the current setting input is inappropriate under the control of the control device 700 .

Further, in the setting screen 1000, when a setting input is made to indicate that there is a possibility that the ejector motor 221 may fall into an overload abnormality, a message to that effect may be displayed. For example, under the control of the control device 700, the display device 760 may change the text boxes of the setting input sections 1020, 1030, 1040, and 1050, in which information that the ejector motor 221 may be overloaded, to a different color (e.g., red). Thereby, the display device 760 can make the user recognize that the content of the current setting input is inappropriate under the control of the control device 700 .

In addition to the control torque pattern image 1010, the setting screen 1000 may display a mold pressure pattern of the mold apparatus 800 or an image representing a lower limit torque pattern of the ejector motor 221 corresponding to the mold pressure pattern. In this case, the graph shape of the control torque pattern of the control torque pattern image 1010 may change according to the details of the setting inputs to the setting input sections 1020 , 1030 , 1040 and 1050 . Thereby, the user can set and input an appropriate control torque pattern while confirming the mold internal pressure pattern of the mold apparatus 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 are possible within the scope of the claims.

For example, in the above-described embodiment, the tip of the compression core pin 832 may have an uneven pattern, and the 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 transfer purposes, strict positioning of the tip of the compression core pin 832 may not be necessary. In this case, the control device 700 may set the control torque pattern of the ejector motor 221 based on the fluctuation pattern of the mold internal pressure and the 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 internal pressure of the mold apparatus 800, there is a possibility that the pattern on the tip of the compression core pin 832 will not be successfully transferred to the molding material due to the pushing 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 pushing back from the molding material, it may fall into an overload state and the injection molding machine 10 may stop abnormally.

In contrast, by setting the control torque pattern of the ejector motor 221 as described above, the control device 700 can suppress the failure of the transfer to the molding material and suppress the deterioration of the work efficiency due to the overload abnormality of the ejector motor 221.

Further, in the above-described embodiments and modifications, the ejector device 200 may have a configuration (an example of a pressurizing mechanism) related to in-mold gate cutting, 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 fluctuation pattern of the physical quantity related to the force opposing the driving of the ejector motor 221, as in the above-described embodiment. The physical quantity relating to the force that opposes the drive of the ejector motor 221 may be, for example, the reaction force acting on the cutting edge for gate cutting from the solidified molding material in the gate portion during gate cutting in the mold. During cutting of the solidified molding material, a relatively large reaction force acts on the cutting edge and a relatively high torque of the ejector motor 221 is required.

For example, if the torque of the ejector motor 221 is relatively small with respect to the strength of the solidified molding material, there is a possibility that gate cutting cannot be achieved due to pushback from the solidified molding material. On the other hand, if the ejector motor 221 continues to output a relatively high torque so as to overcome the pushing back from the solidified molding material, it may fall into an overload state and the injection molding machine 10 may stop abnormally.

On the other hand, the control device 700 sets the control torque pattern of the ejector motor 221 as described above, thereby appropriately performing in-mold gate cutting and suppressing a decrease in work efficiency due to an overload abnormality of the ejector motor 221.

Further, 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 may set the control torque pattern of the actuator (for example, the core tractor motor) that drives the core tractor device based on the fluctuation pattern of the internal mold pressure and the injection pressure of the mold device 800, as in the above embodiment.

For example, if the output torque of an actuator that drives the movable core (an example of a pressurizing mechanism) of the core tractor device is relatively small with respect to the internal pressure of the mold device 800, there is a possibility that the position of the tip of the movable core will deviate from an appropriate position due to pushback from the molding material. On the other hand, if the actuator continues to output a relatively high torque so as to overcome the pushing back from the molding material, the injection molding machine 10 may be overloaded and abnormally stopped.

On the other hand, the control device 700 sets the control torque pattern of the actuator that drives the core tractor device (movable core) as described above, thereby suppressing the deviation of the position of the tip of the movable core from an appropriate position, and suppressing the decrease in work efficiency due to the 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 moving device 700 control device 701 CPU
702 storage medium 703 input interface 704 output interface 750 operation device 760 display device 800 mold device 801 cavity space (cavity)
MM Molding material

Claims (6)

a pressurizing device including a pressurizing mechanism for pressurizing the molding material filled in the mold device; and an actuator for driving the pressurizing mechanism;
a control device that controls the pressure device;
a display device;
The display device displays a screen for setting the control pattern of the actuator by the control device based on the variation pattern of the physical quantity related to the force opposing the driving of the actuator,
On the screen, in the control pattern, a first setting input regarding the magnitude of torque in a first control state in which the torque of the actuator is maintained at a relatively high torque, a second setting input regarding the magnitude of torque in a second control state in which the torque of the actuator is maintained at a relatively low torque, or a third setting input regarding how to change the torque when shifting the torque of the actuator from the first control state to the second control state is possible.
Injection molding machine. a pressurizing device including a pressurizing mechanism for pressurizing the molding material filled in the mold device; and an actuator for driving the pressurizing mechanism;
a control device that controls the pressure device;
a display device;
The display device displays a screen for setting the control device to decrease the torque of the actuator over time,
On the screen, it is possible to input settings regarding how to change the torque when the control device reduces the torque of the actuator over time.
Injection molding machine. a pressurizing device including a pressurizing mechanism for pressurizing the molding material filled in the mold device; and an actuator for driving the pressurizing mechanism;
a control device that controls the pressure device;
a display device;
The display device displays a screen for setting the control pattern of the actuator by the control device based on the variation pattern of the physical quantity related to the force opposing the driving of the actuator,
The control device sets the control pattern regarding the torque of the actuator based on the allowable lower limit torque pattern of the actuator for countering the fluctuation pattern .
injection molding machine. a pressurizing device including a pressurizing mechanism for pressurizing the molding material filled in the mold device; and an actuator for driving the pressurizing mechanism;
a control device that controls the pressure device;
a display device;
The display device displays a screen for setting the control pattern of the actuator by the control device based on the variation pattern of the physical quantity related to the force opposing the driving of the actuator,
The control device sets the control pattern regarding the torque of the actuator based on the allowable upper limit torque pattern for the overloaded state of the actuator .
injection molding machine. a pressurizing device including a pressurizing mechanism for pressurizing the molding material filled in the mold device; and an actuator for driving the pressurizing mechanism;
a control device that controls the pressure device;
a display device;
The display device displays a screen for setting the control pattern of the actuator by the control device based on the variation pattern of the physical quantity related to the force opposing the driving of the actuator,
The control device maintains the upper limit of the torque of the actuator at a relatively high first torque value, then decreases the torque from the first torque value to a relatively low second torque value , and sets the control pattern to maintain the second torque value .
injection molding machine. a pressurizing device including a pressurizing mechanism for pressurizing the molding material filled in the mold device; and an actuator for driving the pressurizing mechanism;
a control device that controls the pressure device;
a display device;
The display device displays a screen for setting the control device to decrease the torque of the actuator over time,
The control device maintains the upper limit of the torque of the actuator at a relatively high first torque value according to the setting input on the screen, and then decreases from the first torque value to a relatively low second torque value and maintains the second torque value.
Injection molding machine.

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