KR20210052316A - Injection molding machine - Google Patents

Abstract

An injection molding machine capable of reducing a load applied to a screw is provided. The injection molding machine includes: a cylinder for heating a molding material; a nozzle provided at the front end of the cylinder; a screw that is disposed to rotate and to move forward and rearward in the cylinder; a driving unit for driving the screw; and a control unit for controlling the driving unit. The control unit lowers the pressure of the molding material on the nozzle side rather than the screw in the cylinder and rotates the screw.

Description

Injection molding machine {INJECTION MOLDING MACHINE}

The present invention relates to an injection molding machine.

This application claims priority based on Japanese Patent Application No. 2019-199301 for which it applied on October 31, 2019. All contents of the application are incorporated by reference in this specification.

In the injection molding machine, the molding material in the injection device is purged during resin replacement or color change.

In Patent Document 1, a molding material is supplied into a heating cylinder, the screw is rotated in one rotational direction, the pressing pressure of the molding material is applied to the front surface of the screwflight part, and the screw is melted while melting the molding material. And the screw is rotated in the other direction of rotation, thereby exerting a pressing force of the molding material on the rear surface of the screwflight part, and applying a force in the direction of retreating the screw to reverse the screw. A molding method is disclosed, characterized in that back pressure is applied.

Japanese Patent Publication No. 4503532

However, when the screw is rotated in a state where the pressure of the molding material accumulated in front of the screw is high, a load is applied to the screw head.

Accordingly, an object of the present invention is to provide an injection molding machine capable of reducing a load applied to a screw.

The injection molding machine of one aspect of the embodiment drives a cylinder for heating a molding material, a nozzle provided at a front end of the cylinder, a screw disposed rotatably and retractably in the cylinder, and the screw. And a control unit for controlling the driving unit, wherein the control unit lowers the pressure of the molding material on the nozzle side than the screw in the cylinder, and rotates the screw.

Advantageous Effects of Invention According to the present invention, an injection molding machine capable of reducing a load applied to a screw can be provided.

1 is a diagram showing a state at the time of completion of mold opening of an injection molding machine according to an embodiment.
Fig. 2 is a diagram showing a state of the injection molding machine according to the embodiment at the time of clamping.
3 is a cross-sectional view of a cylinder and a screw.
4 is an example of a display screen.
5 is a partially enlarged view of an example of a display screen.
6 is a flowchart showing processing in a purging operation.
7 is a schematic cross-sectional view showing a state in a cylinder.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In each drawing, the same or corresponding components are denoted by the same or corresponding reference numerals, and descriptions thereof are omitted.

(Injection molding machine)

1 is a diagram showing a state of an injection molding machine according to an embodiment when mold opening is completed. Fig. 2 is a diagram showing a state of the injection molding machine according to the embodiment at the time of clamping. In the present specification, the X-axis direction, Y-axis direction, and Z-axis direction are directions perpendicular to each other. The X-axis direction and the Y-axis direction indicate the horizontal direction, and the Z-axis direction indicates the vertical direction. When the clamping device 100 is horizontal, the X-axis direction is the mold opening and closing direction, and the Y-axis direction is the width direction of the injection molding machine 10. The negative side in the Y-axis direction is called the operation side, and the positive side in the Y-axis direction is called the semi-operation side.

1 to 2, the injection molding machine 10 includes a clamping device 100 for opening and closing the mold device 800, an ejector device 200 for pushing a molded article molded with the mold device 800, and , An injection device 300 for injecting a molding material into the mold device 800, a moving device 400 for advancing and retreating the injection device 300 with respect to the mold device 800, and each component of the injection molding machine 10 It has a control device 700 for controlling the, and a frame 900 for supporting each component of the injection molding machine (10). The frame 900 includes a clamping device frame 910 for supporting the clamping device 100 and an injection device frame 920 for supporting the injection device 300. The clamping device frame 910 and the injection device frame 920 are respectively installed on the floor 2 through a leveling adjuster 930. In the inner space of the injection device frame 920, the control device 700 is disposed. Hereinafter, each component of the injection molding machine 10 will be described.

(Shaping device)

In the description of the clamping device 100, the moving direction of the movable platen 120 at the time of mold closing (for example, the X-axis positive direction) is forward, and the moving direction of the movable platen 120 at the time of mold opening (For example, the X-axis negative direction) will be described as the rear.

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

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

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

The movable platen 120 is disposed to be movable in the mold opening/closing direction with respect to the clamping device frame 910. On the clamping device frame 910, a guide 101 for guiding the movable platen 120 is provided. A movable mold 820 is mounted on a surface of the movable platen 120 facing the fixed platen 110. By moving the movable platen 120 forward and backward with respect to the stationary platen 110, mold closing, boosting, mold clamping, depressurization, and mold opening of the mold apparatus 800 are performed.

The toggle support 130 is disposed at a distance from the fixed platen 110 and is mounted on the clamping device frame 910 so as to be movable in the mold opening/closing direction. However, the toggle support 130 may be disposed to be movable along a guide installed on the clamping device frame 910. The guide of the toggle support 130 may be common with the guide 101 of the movable platen 120.

However, in this embodiment, the fixed platen 110 is fixed with respect to the clamping device frame 910, and the toggle support 130 is disposed to be movable in the mold opening and closing direction with respect to the clamping device frame 910, but toggle The support 130 may be fixed with respect to the clamping device frame 910, and the fixed platen 110 may be disposed to be movable in the mold opening/closing direction with respect to the clamping device frame 910.

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

However, in this embodiment, as the clamping force detector for detecting clamping force, the tie bar deformation detector 141 is used, but the present invention is not limited thereto. The clamping force detector is not limited to a strain gauge type, and may be a piezoelectric type, a capacitive type, a hydraulic type, an electronic type, or the like, and the mounting position thereof is also not limited to the tie bar 140.

The toggle mechanism 150 is disposed between the movable platen 120 and the toggle support 130, and moves the movable platen 120 in the mold opening/closing direction with respect to the toggle support 130. The toggle mechanism 150 is constituted by a crosshead 151, a pair of link groups, and the like. Each of the pair of links has a first link 152 and a second link 153 that are flexibly connected with a pin or the like. The first link 152 is pivotably mounted with a pin or the like with respect to the movable platen 120. The second link 153 is pivotably mounted with a pin or the like with respect to the toggle support 130. The second link 153 is mounted on the crosshead 151 through the third link 154. When the crosshead 151 is moved forward and backward with respect to the toggle support 130, the first link 152 and the second link 153 flex, and the movable platen 120 moves forward and backward with respect to the toggle support 130.

However, the configuration of the toggle mechanism 150 is not limited to the configurations shown in FIGS. 1 and 2. For example, in FIGS. 1 and 2, the number of nodes in each link group is 5, but may be 4, and one end of the third link 154 is It may be coupled to a node.

The mold motor 160 is mounted on the toggle support 130 and operates the toggle mechanism 150. The clamping motor 160 moves the crosshead 151 forward and backward with respect to the toggle support 130, thereby flexing the first link 152 and the second link 153, so that the movable platen with respect to the toggle support 130 Advance (120). The clamping motor 160 is directly connected to the motion conversion mechanism 170, but may be connected to the motion conversion mechanism 170 through a belt or a pulley.

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

The mold clamping device 100 performs a mold closing step, a pressure boosting step, a clamping step, a depressing step, a mold opening step, and the like under control by the control device 700.

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

However, the crosshead position detector that detects the position of the crosshead 151, and the crosshead movement speed detector that detects the moving speed of the crosshead 151 are not limited to the clamping motor encoder 161, and a general one is used. I can. In addition, the movable platen position detector for detecting the position of the movable platen 120, and the movable platen movement speed detector for detecting the moving speed of the movable platen 120 are not limited to the clamping motor encoder 161. , You can use the general one.

In the boosting process, the clamping force is generated by further driving the clamping motor 160 to further advance the crosshead 151 from the mold closing completed position to the clamping position.

In the clamping step, the clamping motor 160 is driven to maintain the position of the crosshead 151 at the clamping position. In the clamping step, the clamping force generated in the boosting step is maintained. In the 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. do. By solidifying the filled molding material, a molded article is obtained.

The number of cavity spaces 801 may be one or may be plural. In the latter case, a plurality of molded articles are obtained at the same time. An insert material may be disposed in a part of the cavity space 801, and a molding material may be filled in another part of the cavity space 801. A molded article in which the insert material and the molding material are integrated is obtained.

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

In the mold opening process, the movable platen 120 is retracted and the movable mold 820 is fixed by retreating the crosshead 151 from the mold opening position to the mold opening completion position at a set moving speed by driving the clamping motor 160. It is separated from the mold 810. After that, the ejector device 200 pushes the molded product from the movable mold 820.

The setting conditions in the mold closing process, the boosting process and the mold clamping process are set as a series of setting conditions, and are collectively set. For example, the moving speed or position of the crosshead 151 in the mold closing process and the boosting process (including the mold closing start position, the moving speed switching position, the mold closing completed position, and the clamping position), and the clamping force are set in a series. As a condition, it is set collectively. The mold closing start position, the moving speed switching position, the mold closing completed position, and the mold closing position are arranged in this order from the rear side to the front side, and indicate the start or end point of the section in which the moving speed is set. For each section, the moving speed is set. The number of movement speed switching positions may be one, or may be plural. The movement speed switching position does not need to be set. Only one of the clamping positions and clamping force may be set.

The setting conditions in the depressurization process and the mold opening process are also set in the same way. For example, the moving speed or position (the mold opening position, the moving speed switching position, and the mold opening completion position) of the crosshead 151 in the depressurization step and the mold opening step are set collectively 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 indicate the starting point or the end point of the section in which the moving speed is set. For each section, the moving speed is set. The number of movement speed switching positions may be one, or may be plural. The movement speed switching position does not need to be set. The mold opening position and the mold closing completed position may be the same position. Moreover, the mold opening completion position and the mold closing start position may be the same position.

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

By the way, the toggle mechanism 150 amplifies the driving force of the mold motor 160 and transmits it to the movable platen 120. The amplification magnification is also called a toggle magnification. The toggle magnification varies according to the angle θ formed by the first link 152 and the second link 153 (hereinafter, also referred to as “link angle θ”). The link angle θ is 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 exchange of the mold apparatus 800 or temperature change of the mold apparatus 800, the mold thickness is adjusted so that a predetermined clamping force can be obtained during mold clamping. In the mold thickness adjustment, for example, the fixed platen 110 so that the link angle θ of the toggle mechanism 150 becomes a predetermined angle at the time of the mold touch that the movable mold 820 touches the fixed mold 810. ) And the interval (L) between the toggle support 130.

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 fixed platen 110 and the toggle support 130. However, the timing of the mold thickness adjustment is performed, for example, from the end of the molding cycle to the start of the next molding cycle. The mold thickness adjustment mechanism 180 includes, for example, a screw shaft 181 formed at the rear end of the tie bar 140, and a screw nut 182 that is rotatably supported by the toggle support 130 so as not to advance and retreat. And, it has a mold thickness adjustment motor 183 for rotating the screw nut 182 screwed to the screw shaft 181.

The screw shaft 181 and the screw 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 plurality of screw nuts 182 through the rotational driving force transmission unit 185. The plurality of screw nuts 182 can be rotated synchronously. However, it is also possible to individually rotate the plurality of screw nuts 182 by changing the transmission path of the rotational driving force transmission unit 185.

The rotational driving force transmission unit 185 is constituted by gears or the like, for example. In this case, a manual gear is formed on the outer periphery of each screw nut 182, a driving gear is mounted on the output shaft of the mold thickness adjustment motor 183, and a plurality of manual gears and an intermediate gear meshing with the driving gear are provided with a toggle support ( 130) is rotatably supported in the central part. However, the rotational driving force transmission unit 185 may be configured with a belt, a pulley, or the like, instead of a gear.

The operation of the mold thickness adjustment mechanism 180 is controlled by the control device 700. The control device 700 drives the mold thickness adjusting motor 183 to rotate the screw nut 182. As a result, the position of the toggle support 130 with respect to the tie bar 140 is adjusted, and the distance L between the fixed platen 110 and the toggle support 130 is adjusted. However, a plurality of mold thickness adjustment 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 rotation amount and the rotation direction 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 adjusting motor encoder 184 is used for monitoring and controlling the position and the interval L of the toggle support 130. However, the toggle support position detector for detecting the position of the toggle support 130 and the distance detector for detecting the distance L are not limited to the mold thickness adjusting motor encoder 184, and a general one may be used.

However, the mold clamping apparatus 100 of the present embodiment is a horizontal type in which the mold opening and closing direction is a horizontal direction, but may be a vertical type in which the mold opening and closing direction is a vertical direction.

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

(Ejector device)

In the description of the ejector device 200, as in the description of the clamping device 100, the moving direction of the movable platen 120 at the time of mold closing (for example, the X-axis positive direction) is forward, and the movable plate at the time of mold opening The movement direction of the button 120 (for example, the negative X-axis direction) is described as the rear.

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

The ejector rod 210 is disposed in the through hole of the movable platen 120 so as to be able to advance and retreat. The front end of the ejector rod 210 is in contact with a movable member 830 disposed in the inside of the movable mold 820 so as to advance and retreat. The front end of the ejector rod 210 may or may not be connected to the movable member 830.

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

The ejector device 200 performs a pushing process under control by the control device 700. In the pushing step, by moving the ejector rod 210 forward from the standby position to the pushing position at a set moving speed, the movable member 830 is moved forward and the molded article is pushed out. Thereafter, the ejector motor is driven to retreat the ejector rod 210 at a set moving speed, and the movable member 830 is retracted to the original standby position.

The position or moving speed of the ejector rod 210 is detected using, for example, an ejector motor encoder. The ejector motor encoder detects the rotation of the ejector motor and sends a signal indicating the detection result to the control device 700. However, 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 the ejector motor encoder, and a general one may be used.

(Injection device)

In the description of the injection device 300, unlike the description of the clamping device 100 or the description of the ejector device 200, the moving direction of the screw 330 at the time of filling (for example, the negative X-axis direction) is forward. Then, the moving direction of the screw 330 at the time of weighing (for example, the X-axis positive direction) will be described as the rear.

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

The cylinder 310 heats the molding material supplied to the inside from the supply port 311. The molding material contains, for example, resin. The molding material is formed in, for example, pellets, and is supplied to the supply port 311 in a solid state. The supply port 311 is formed at the rear of the cylinder 310. A cooler 312 such as a water cooling cylinder is provided on the outer periphery of the rear portion of the cylinder 310. In front of the cooler 312, a heater 313 such as a band heater and a temperature detector 314 are provided on the outer periphery of the cylinder 310.

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

The nozzle 320 is provided at the front end of the cylinder 310 and is pressed against the mold apparatus 800. On the outer periphery of the nozzle 320, a heater 313 and a temperature detector 314 are provided. The control device 700 controls the heater 313 so that the detection temperature of the nozzle 320 becomes a set temperature.

The screw 330 is disposed in the cylinder 310 so as to be rotatable and advancing and retreating. When the screw 330 is rotated, the molding material is sent forward along the spiral groove of the screw 330. The molding material is gradually melted by the heat from the cylinder 310 while being sent forward. As the liquid molding material is sent to the front of the screw 330 and accumulates in the front of the cylinder 310, the screw 330 is retracted. Thereafter, when the screw 330 is advanced, the liquid molding material accumulated in front of the screw 330 is injected from the nozzle 320 and filled into the mold apparatus 800.

All of the screw 330 is a backflow prevention valve that prevents backflow of the molding material from the front to the rear of the screw 330 when pushing the screw 330 forward, and a backflow prevention ring 331 is mounted so as to move forward and backward. do.

When the screw 330 is advanced, the backflow prevention ring 331 is pushed to the rear by the pressure of the molding material in front of the screw 330, and the screw 330 until a closed position (see Fig. 2) that blocks the flow path of the molding material. ) Relative to the retreat. This prevents the molding material accumulated in front of the screw 330 from flowing backward.

On the other hand, when rotating the screw 330, the backflow prevention ring 331 is pushed forward by the pressure of the molding material sent forward along the spiral groove of the screw 330 to open the flow path of the molding material. It advances relative to the screw 330 to the open position (see Fig. 1). Thereby, the molding material is sent to the front of the screw 330.

The backflow prevention ring 331 may be of an idle type that rotates together with the screw 330 and a non-idle rotation type that does not rotate together with the screw 330.

However, the injection device 300 may have a drive source that advances and retreats the backflow prevention ring 331 with respect to the screw 330 between the open position and the closed position.

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

The injection motor 350 advances and retreats the screw 330. Between the injection motor 350 and the screw 330, a motion conversion mechanism for converting the rotational motion of the injection motor 350 into a linear motion of the screw 330 is provided. The motion conversion mechanism has, for example, a screw shaft and a screw nut that is screwed to the screw shaft. A ball, roller, 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 or the like.

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

The pressure detector 360 sends a signal indicating the detection result to the control device 700. The detection result of the pressure detector 360 is used for control and monitoring of the pressure received by the screw 330 from the molding material, the back pressure to the screw 330, and the pressure acting on the molding material from the screw 330.

The injection device 300 performs a metering process, a filling process, a holding pressure process, and the like under control by the control device 700. The filling process and the holding pressure process may be collectively called the injection process.

In the weighing step, the weighing motor 340 is driven to rotate the screw 330 at a set rotational speed, and the molding material is sent forward along the spiral groove of the screw 330. Accordingly, the molding material is gradually melted. As the liquid molding material is sent to the front of the screw 330 and accumulates in the entire cylinder 310, the screw 330 is retracted. The rotational speed of the screw 330 is detected using, for example, a metering motor encoder 341. The metering motor encoder 341 detects the rotation of the metering motor 340 and sends a signal indicating the detection result to the control device 700. However, the screw rotation speed detector for detecting the rotation speed of the screw 330 is not limited to the measuring motor encoder 341, and a general one may be used.

In the metering process, in order to limit the rapid retraction of the screw 330, the injection motor 350 may be driven to apply a set back pressure to the screw 330. The back pressure to the screw 330 is detected using, for example, a pressure detector 360. The pressure detector 360 sends a signal indicating the detection result to the control device 700. When the screw 330 retreats to the weighing completion position and a predetermined amount of molding material is accumulated in front of the screw 330, the weighing process is completed.

The position and rotation speed of the screw 330 in the weighing step are set collectively as a series of setting conditions. For example, a weighing start position, a rotation speed switching position, and a weighing completion position are set. These positions are arranged in this order from the front side to the rear side, and indicate the start point or end point of the section in which the rotational speed is set. For each section, the rotational speed is set. The number of rotational speed switching positions may be one, or may be plural. The rotation speed switching position does not need to be set. In addition, back pressure is set for each section.

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

The position and moving speed of the screw 330 in the filling process are set collectively as a series of setting conditions. For example, a charging start position (also referred to as a "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 indicate the start point or end point of the section in which the moving speed is set. For each section, the moving speed is set. The number of movement speed switching positions may be one, or may be plural. The movement speed switching position does not need to be set.

For each section in which the moving speed of the screw 330 is set, an upper limit value of the pressure of the screw 330 is set. The pressure of the screw 330 is detected by the pressure detector 360. When the detected value of the pressure detector 360 is less than or equal to the set pressure, the screw 330 is advanced at the set moving speed. On the other hand, when the detected value of the pressure detector 360 exceeds the set pressure, for the purpose of protecting the mold, the screw 330 is slower than the set moving speed so that the detected value of the pressure detector 360 is less than the set pressure. It advances at the speed of movement.

However, 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 V/P switching may be performed. Immediately before the V/P switching, instead of stopping the screw 330, the screw 330 may be moved forward or backward at a slow speed. Further, the screw position detector for detecting the position of the screw 330 and the screw movement speed detector for detecting the moving speed of the screw 330 are not limited to the injection motor encoder 351, and a general one can be used.

In the holding pressure process, the injection motor 350 is driven to push the screw 330 forward to maintain the pressure of the molding material at the front end of the screw 330 (hereinafter, also referred to as “holding pressure”) at a set pressure. Then, the molding material remaining in the cylinder 310 is pushed toward the mold apparatus 800. It is possible to make up for the insufficient molding material due to the cooling shrinkage in the mold apparatus 800. The holding pressure is detected using the pressure detector 360, for example. The pressure detector 360 sends a signal indicating the detection result to the control device 700. The set value of the holding pressure may be changed according to the elapsed time from the start of the holding pressure step or the like. A plurality of holding pressures and holding times for holding the holding pressure in the holding pressure step may be set, respectively, or may be set collectively as a series of setting conditions.

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

However, although the injection apparatus 300 of this embodiment is an in-line screw system, it may be a pre-plastic sizing system or the like. In the injection apparatus of the pre-plastic sizing method, a molding material melted in a plasticizing cylinder is supplied to an injection cylinder, and the molding material is injected from the injection cylinder into a mold apparatus. In the plasticizing cylinder, the screw is arranged rotatably and non-advancing and retracting, or the screw is arranged rotatably and retractable. On the other hand, in the injection cylinder, a plunger is disposed so as to be able to advance and retreat.

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

(Moving device)

In the description of the moving device 400, as in the description of the injection device 300, the moving direction of the screw 330 at the time of filling (for example, the negative X-axis direction) is forward, and the screw 330 at the time of weighing ) In the direction of movement (for example, the X-axis positive direction) as the rear.

The moving device 400 advances and retreats the injection device 300 with respect to the mold device 800. Further, the moving device 400 presses the nozzle 320 against the mold device 800 to generate a nozzle touch pressure. The moving device 400 includes a hydraulic pump 410, a motor 420 as a driving source, a hydraulic cylinder 430 as a hydraulic actuator, and the like.

The hydraulic pump 410 has a first port 411 and a second port 412. The hydraulic pump 410 is a pump capable of rotating in both directions, and by switching the rotation direction of the motor 420, a working fluid (for example, oil) is supplied from either of the first port 411 and the second port 412. It inhales and discharges it from the other side to generate hydraulic pressure. However, the hydraulic pump 410 may suck the working fluid from the tank and discharge the working fluid from either one of the first port 411 and the second port 412.

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

The hydraulic cylinder 430 has a cylinder body 431, a piston 432, and a piston rod 433. The cylinder body 431 is fixed to the injection device 300. The piston 432 divides the inside of the cylinder body 431 into a front chamber 435 as a first chamber and a rear chamber 436 as a second chamber. The piston rod 433 is fixed with respect to the fixed platen 110.

The front chamber 435 of the hydraulic cylinder 430 is connected to the first port 411 of the hydraulic pump 410 through the first flow path 401. As the working fluid discharged from the first port 411 is supplied to the front chamber 435 through the first flow path 401, the injection device 300 is pushed forward. The injection device 300 is advanced, and the nozzle 320 is pressed against the fixed mold 810. The front chamber 435 functions as a pressure chamber for generating a nozzle touch pressure of the nozzle 320 by the pressure of the working fluid supplied from the hydraulic pump 410.

On the other hand, the rear chamber 436 of the hydraulic cylinder 430 is connected to the second port 412 of the hydraulic pump 410 through the second flow path 402. The working 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, so that the injection device 300 is pushed to the rear. The injection device 300 is retracted so that the nozzle 320 is separated from the fixed mold 810.

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

(Control device)

The control device 700 is constituted by, for example, a computer, and as shown in Figs. 1 to 2, a CPU (Central Processing Unit) 701, a storage medium 702 such as a memory, and an input interface 703 Wow, it has an output interface 704. The control device 700 performs various controls by executing the program stored in the storage medium 702 on the CPU 701. Further, the control device 700 receives a signal from the outside through the input interface 703 and transmits the signal to the outside through the output interface 704.

The control device 700 repeatedly manufactures a molded article by repeatedly performing a weighing process, a mold closing process, a boosting process, a clamping process, a filling process, a holding process, a cooling process, a depressurizing process, a mold opening process, and a pushing process. do. A series of operations for obtaining a molded article, for example, an operation from the start of the weighing step to the start of the next weighing step, is also referred to as "short" or "molding cycle". In addition, the time required for one shot is also referred to as "molding cycle time" or "cycle time".

One molding cycle includes, for example, a weighing process, a mold closing process, a boosting process, a mold closing process, a filling process, a holding pressure process, a cooling process, a depressurizing process, a mold opening process, and a pushing process in this order. The sequence number here is the sequence number of the start of each process. The filling process, the holding pressure process, and the 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.

However, in order to shorten the molding cycle time, a plurality of steps may be performed at the same time. For example, the weighing step may be performed during the cooling step of the previous molding cycle or may be performed during the clamping step. In this case, the mold closing step may be performed at the beginning of the molding cycle. In addition, the filling process may be started during the mold closing process. In addition, the pushing process may be started during the mold opening process. When an on-off valve for opening and closing the flow path of the nozzle 320 is provided, the mold opening process may be started during the metering process. This is because even if the mold opening process is started during the metering process, the molding material does not leak from the nozzle 320 if the on-off valve closes the flow path of the nozzle 320.

However, one molding cycle may have steps other than the weighing step, mold closing step, boosting step, clamping step, filling step, holding pressure step, cooling step, depressurizing step, mold opening step, and pushing step.

For example, after completion of the holding pressure step and before the start of the weighing step, a pre-weighing color whitening step may be performed in which the screw 330 is retracted to a preset weighing start position. It is possible to reduce the pressure of the molding material accumulated in front of the screw 330 before the start of the weighing process, so that the rapid retraction of the screw 330 at the start of the weighing process can be prevented.

Further, after the completion of the weighing process, before the start of the filling process, a color whitening process after weighing in which the screw 330 is retracted to a preset filling start position (also referred to as "injection start position") may be performed. 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 accepts an input operation by a user or a display device 760 that displays a display screen. The operation device 750 and the display device 760 are constituted by, for example, a touch panel, and may be integrated. The touch panel as the display device 760 displays a display screen under control by the control device 700. Information such as the settings of the injection molding machine 10 and the current state of the injection molding machine 10 may be displayed on the display screen of the touch panel. Further, on the display screen of the touch panel, for example, an input operation unit such as a button for accepting an input operation by a user, an input field, etc. may be displayed. The touch panel as the manipulation device 750 detects an input manipulation on a display screen by a user and outputs a signal according to the input manipulation to the control device 700. Thereby, for example, the user can set the injection molding machine 10 (including input of a set value) and the like by operating the input operation unit provided on the display screen while checking the information displayed on the display screen. In addition, by the user manipulating the input operation unit provided on the display screen, the injection molding machine 10 corresponding to the input operation unit can be operated. However, the operation of the injection molding machine 10 may be, for example, an operation (including a stop) of the 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 a switching of a display screen displayed on a touch panel as the display device 760, or the like.

However, although the operation device 750 and the display device 760 of the present embodiment have been described as being integrated as a touch panel, they may be provided independently. In addition, a plurality of operating devices 750 may be provided. The operating device 750 and the display device 760 are disposed on the operating side (Y-axis negative direction) of the clamping device 100 (more specifically, the fixed platen 110).

(Structure of cylinder and screw)

3 is a cross-sectional view of the cylinder 310 and the screw 330. However, in Fig. 3, in the molding cycle, the screw 330 is shown in a state when it is most retracted.

The screw 330 is disposed so as to be able to advance and retreat in the interior of the cylinder 310 and to be rotatable. The screw 330 has a screw head 332, a sealing ring 333, and a flight screw 334 in this order from the front end to the rear. The screw head 332 and the sealing ring 333 rotate together with the flight screw 334 and advance and retreat together with the flight screw 334.

The screw head 332 has a tapered head body portion 332a and a rod portion 332b connecting the rear end surface of the head body portion 332a and the front end surface of the sealing ring 333. The front end of the rod portion 332b is smaller than the rear end surface of the head body portion 332a, and the rear end of the rod portion 332b is smaller than the front end surface of the sealing ring 333. The rear end surface of the head body portion 332a is perpendicular to the axial direction of the cylinder 310 in FIG. 3, but may be inclined.

The flight screw 334 has a rotation shaft 334a and a flight 334b spirally provided on the outer periphery of the rotation shaft 334a. A spiral groove 335 is formed along the flight 334b. When the metering motor 340 is driven to rotate the flight screw 334, the molding material is sent forward along the groove 335 of the flight screw 334.

The flight screw 334 has a first section Z1, a second section Z2, and a third section Z3 in this order from the rear end toward the front. The first section Z1 is a section in which a solid phase of a molding material exists. The second section Z2 is a section in which both the solid phase and the liquid phase of the molding material exist. The third section Z3 is a section in which the liquid phase of the molding material is present.

The depth of the groove 335 is deeper in the first section Z1, shallower in the third section Z3, and shallower toward the downstream side in the second section Z2. In this case, the first section Z1 is also called a supply section, the second section Z2 is called a compression section, and the third section Z3 is also called a metering section. However, the depth of the groove 335 may be constant.

The screw 330 has a non-return ring 331 around the rod portion 332b of the screw head 332. The backflow prevention ring 331 is formed in a ring shape and has a through hole through which the rod portion 332b is inserted. The backflow prevention ring 331, along the rod portion 332b, is a closed position (see Fig. 2) in contact with the front end of the sealing ring 333, and after the head body portion 332a of the screw head 332 It moves between the open positions (see Figs. 1 and 3) in contact with the end face. However, the anti-return ring 331 is a non-idling type that does not rotate together with the flight screw 334.

When the injection motor 350 is driven to advance the flight screw 334, the backflow prevention ring 331 is pushed backward by the pressure of the molding material accumulated in the front of the screw head 332. Thereby, the backflow prevention ring 331 moves to the closed position along the rod portion 332b, and prevents the molding material accumulated in the front of the screw head 332 from flowing backward.

On the other hand, when the metering motor 340 is driven to rotate the flight screw 334, the molding material is sent along the spiral groove 335 formed in the flight screw 334, and backflow is prevented by the pressure of the molding material. The ring 331 is pushed forward. Thereby, the backflow prevention ring 331 moves to the open position along the rod part 332b, and the molding material is sent to the front of the screw head 332.

The rod portion 332b of the screw head 332 passes through the backflow prevention ring 331 and the sealing ring 333. The rear side of the rod portion 332b is screwed, and is fixed by entering a screw hole provided at the front end of the flight screw 334. Thereby, the screw head 332, the backflow prevention ring 331, and the sealing ring 333 are separated from the flight screw 334, so that replacement and maintenance are possible. Here, when the flight 334b of the flight screw 334 is formed in the direction of the right screw, for example, a left screw is formed in the rod portion 332b of the screw head 332. For this reason, when the flight screw 334 is rotated in the electrostatic direction (the first rotational direction, the direction in which the molding material is sent forward), torque is applied from the molding material in the direction of tightening the screw head 332 to the flight screw 334. .

Here, when purging the molding material in the cylinder 310, by inverting the screw 330 and applying reverse back pressure to the screw 330, the molding material (resin) adhered to the back side of the flight 334b or Colorants (pigments, etc.) can be removed suitably. However, when the flight screw 334 is rotated in the reverse direction (the second rotation direction, the direction of sending the molding material to the rear), torque is applied from the molding material in the direction in which the screw head 332 is released from the flight screw 334, There is a fear that the screw head 332 may be loosened.

Next, a purge operation in the injection molding machine 10 of the present embodiment will be described. First, an example of a display screen displayed on the display device 760 used when inputting the setting of the purge operation will be described with reference to FIG. 4. 4 is an example of the display screen 30.

The display screen 30 has a status display section 31 that displays the state of the injection molding machine 10. Lamps 31a to 32l indicating the state of the injection molding machine 10 are displayed on the state display unit 31.

The lamp 31a is a lamp that is lit when the mold clamping device 100 is mold-opened (opened). The lamp 31b is a lamp that is lit when the clamping device 100 is mold-closed (fully closed). The lamp 31c is a lamp that lights up when the ejector rod 210 is retracted to the standby position. The lamp 31d is a lamp that lights up while the injection molding machine 10 is at rest. The lamp 31e is a lamp that is lit during the cooling operation of the injection molding machine 10. The lamp 31f is a lamp that is lit during the delay operation of the injection molding machine 10. For example, when a waiting time has been set after completion of the holding pressure step until starting the weighing step, the lamp 31f lights up during this waiting time. The lamp 31g is a lamp that is lit when a nozzle touch is applied to the mold apparatus 800 to press the nozzle 320. The lamp 31h is a lamp that is lit during the holding pressure process of the injection molding machine 10. The lamp 31i is a lamp that lights up during the filling process of the injection molding machine 10. The lamp 31j is a lamp that is lit during the weighing process of the injection molding machine 10. The lamp 31k is a lamp that lights up after completion of the weighing process of the injection molding machine 10. The lamp 31l is a lamp that lights according to the state of the heater 313. For example, during heating of the heater 313, the lamp 31l lights in red, and after the heating of the heater 313 is completed, the lamp 31l lights in green.

Further, the display screen 30 has an operation icon display unit 32. On the operation icon display unit 32, icons 32a to 32g are displayed. By operating the icons 32a to 32g, an operation corresponding to the icons 32a to 32g is performed.

By operating the icon 32a, icons displayed on the operation icon display unit 32 are switched. By operating the icon 32b, the display screen 30 is shifted to a special screen. The icon 32c displays an alert state. For example, during the alert, the display (color, lighting, blinking, etc.) of the icon 32c changes from the normal state. By operating the icon 32c, it shifts to the display screen displaying the alert contents. By operating the icon 32d, it shifts to the display screen for setting the timer. By setting the timer, for example, a device such as the heater 313 can be turned on at a preset date and time. By operating the icon 32e, the display screen 30 is locked. That is, operations other than the icon 32e are not accepted. Again, by operating the icon 32e, the lock of the display screen 30 is released. By operating the icon 32f, a screenshot of the display screen 30 is captured. The icon 32g indicates the user level. For example, in Fig. 4, an icon indicating that the user level is "5" is displayed. By operating the icon 32g, it shifts to the display screen for switching the user level.

Further, the display screen 30 has a first tab display portion 33 and a display area 34. Tabs 33a to 33i are displayed on the first tab display portion 33. By selecting the tabs 33a to 33i, display contents corresponding to the selected tabs 33a to 33i are displayed in the display area 34.

By selecting the tab 33a, information on the procedure is displayed in the display area 34. By selecting the tab 33b, information on mold opening/closing is displayed in the display area 34. By selecting the tab 33c, information about the temperature is displayed in the display area 34. By selecting the tab 33d, information related to ejection is displayed in the display area 34. By selecting the tab 33e, information related to the list setting is displayed in the display area 34. By selecting the tab 33f, information related to the monitor is displayed in the display area 34. By selecting the tab 33g, information about the state of the injection molding machine 10 is displayed on the display area 34. By selecting the tab 33h, information about equipment (for example, a material supply device, a take-out device for taking out a molded product, etc.) linked with the injection molding machine 10 is displayed on the display area 34. By selecting the tab 33i, information on steps is displayed in the display area 34.

In the following description, the first tab display unit 33 assumes that the tab 33a for displaying information on the procedure on the display area 34 is selected.

The display area 34 has a second tab display portion 35 and a display area 36. On the second tab display unit 35, tabs 35a to 35d and icons 35e to 35g are displayed. By selecting the tabs 35a to 35d, display contents corresponding to the selected tabs 35a to 35d are displayed in the display area 36.

By selecting the tab 35a, information about equipment (for example, a material supply device, etc.) linked to the injection molding machine 10 is displayed on the display area 36. By selecting the tab 35b, information related to memory is displayed in the display area 36. By selecting the tab 35c, information related to mold mounting is displayed in the display area 36. By selecting the tab 35d, information on purging is displayed in the display area 36.

By operating the icon 35e, the tabs displayed on the second tab display unit 35 are switched. By operating the icon 35f, a list of tabs that can be selected on the second tab display unit 35 is displayed. By operating the icon 35g, the tabs displayed on the second tab display unit 35 are switched.

In the following description, in the second tab display unit 35, it is assumed that the tab 35d for displaying information about purge on the display area 36 is selected.

The display area 36 includes display areas 37 and 38, a third tab display portion 39 and a display area 40.

In the display area 37, detection values of the screw position, filling pressure, screw rotation speed, and measurement torque are displayed. Also, the total peak, the switching position of VP conversion, and the detection value of the weighing time are displayed.

In the display area 38, information about the temperature of the cylinder 310 is displayed. In the display field 38a, the detection temperature for each zone of the cylinder 310 detected by the temperature detector 314 and the detection temperature of the cooler 312 are displayed. The input field 38b is a main setting (setting at the time of molding), and is configured such that the temperature for each zone of the cylinder 310 and the set temperature of the cooler 312 can be input. The input field 38c is a setting at the time of purging, and is configured so that the temperature for each zone of the cylinder 310 can be input. The input field 38d is set at the time of keeping warm, and is configured so that the temperature for each zone of the cylinder 310 can be input. The selection field 38e is configured to be able to select which of the settings set in the input fields 38b to 38d to control the heater 313 to be used. However, in the example of FIG. 4, the setting at the time of purging is selected.

On the third tab display portion 39, tabs 39a to 39d and icons 39e to 39g are displayed. By selecting the tabs 39a to 39d, display contents corresponding to the selected tabs 39a to 39d are displayed in the display area 40.

By selecting the tab 39a, information related to fuzzy monitoring is displayed in the display area 40. By selecting the tab 39b, information on the pigment replacement purge is displayed in the display area 40. By selecting the tab 39c, explanatory information is displayed in the display area 40. By selecting the tab 39d, information about the material supply device (GS loader) is displayed in the display area 40.

By operating the icon 39e, the tabs displayed on the third tab display unit 39 are switched. By operating the icon 39f, a list of tabs that can be selected on the third tab display unit 39 is displayed. By operating the icon 39g, the tabs displayed on the third tab display unit 39 are switched.

In the following description, in the third tab display unit 39, it is assumed that the tab 39b for displaying information on the pigment replacement purge on the display area 40 is selected.

Next, an example of the display contents displayed on the display area 40 will be described with reference to FIG. 5. 5 is a partially enlarged view of an example of the display screen 30.

The display area 40 is a charging operation setting unit 41, a holding pressure operation setting unit 42, a weighing operation setting unit 43, a vibration operation setting unit 44, a reverse purge setting unit 45, a monitoring setting unit. It has (46).

The charging operation setting unit 41 has input fields 41a to 41f. Here, in the filling operation, the injection motor 350 is driven to advance the screw 330, and the molded material measured by the metering operation described later is injected from the nozzle 320, and the molding material is injected from the cylinder 310. It is an operation to discharge. The input field 41a is configured so that the delay time of the charging operation can be input. The input field 41b is configured such that the switching position of V/P switching for switching from the charging operation to the holding pressure operation described later can be input. The input field 41c is configured such that the forward speed of the screw 330 in the charging operation can be input.

Further, in the charging operation, after driving the injection motor 350 to advance the screw 330, it is possible to perform a retraction operation of retreating the screw 330. By performing the retraction operation, the molding material flows in inertia, and it becomes easy to remove the molding material or the colorant adhering to the inner wall of the cylinder 310 from the front of the screw head 332 to the nozzle 320. In the input field 41d, when performing the retreat operation, the delay time from the end of the advance to the start of the retreat can be input. The input field 41e is configured such that the retreat position when the screw 330 is retracted can be input. However, when the retreat operation is not performed, "OFF" is displayed in the input field 41e. The input field 41f is configured such that the retraction speed at the time of retreating the screw 330 can be input.

The holding pressure operation setting unit 42 has input fields 42a to 42b. Here, the holding pressure operation is an operation in which the injection motor 350 is driven to push the screw 330 forward, and the holding pressure at the front end of the screw 330 is maintained at a set pressure. The input field 42a is configured so that the holding pressure time can be input. However, when the holding pressure operation is not performed, the holding pressure time is displayed as 0 seconds. The input field 42b is configured so that the holding pressure can be input.

The weighing operation setting unit 43 has input fields 43a to 43d. Here, in the metering operation, the metering motor 340 is driven to rotate the screw 330 at a set rotational speed, and the molding material is sent forward along the spiral groove of the screw 330. The input field 43a is configured so that the position of the color white can be input. The input field 43b is configured so that the position of the measurement completion can be input. The input field 43c is configured so that the set back pressure can be input. The input field 43d is configured such that the rotational speed of the screw 330 in the weighing operation can be input.

The vibration operation setting unit 44 has a selection field 44a and an input field 44b to 44g. Here, the vibration operation is an operation of driving the injection motor 350 to vibrate the screw 330 (forward and backward). By vibrating operation, removal of the molding material or colorant adhering to the inner wall of the cylinder 310 from the front of the screw head 332 to the nozzle 320 is promoted. The selection column 44a is configured so that the timing at which the vibration operation is performed can be selected. For example, in the selection column 44a, it is possible to select from "at the completion of the holding pressure operation", "at the completion of the weighing operation", "both (when the holding operation is completed and when the weighing operation is completed)", and "no vibration operation". However, when the vibration operation is not performed, "OFF" is displayed in the selection column 44a. The input field 44b is configured so that the direction of vibration (for example, forward and backward) during the vibration operation can be input. The input field 44c is configured such that the moving distance during the vibration operation can be input. The input field 44d is configured such that the moving speed of the screw 330 during the vibration operation can be input. The input field 44e is configured such that the number of vibrations during the vibration operation can be input. The input field 44f is configured to allow input of a delay time before the start of forward movement during the vibration operation. The input field 44g is configured such that the delay time before the start of the reverse movement during the vibration operation can be input.

The reverse purge setting unit 45 has a selection field 45a and an input field 45b to 45f. Here, the reverse purge operation is an operation of reversing the screw 330 by driving the metering motor 340 during the purge operation. Thereby, the molding material in the groove 335 moves back and forth. When the screw 330 is electrostatically charged, a back pressure is applied to the screw 330 to remove the molding material or colorant adhering to the surface side of the flight 334b. By reversing the screw 330, a reverse back pressure is applied to the screw 330, so that the molding material or colorant adhered to the back side of the flight 334b can be removed. The selection field 45a is configured to be able to select whether or not to perform the reversing operation. However, when the reversing operation is not performed, "OFF" is displayed in the selection column 45a.

The input field 45b is configured to allow input of information on timing at which the reversing operation is performed. For example, the input field 45b is configured so that the number of divisions of the weighing position can be input. The measurement completion position input in the input field 43b is divided by the number of divisions input in the input field 45b. When reaching each divided position, the reversing operation is performed.

The input field 45c is configured such that the delay time before the start of the reversing operation can be input. The input field 45d is configured so that the operation time during the reversing operation can be input. The input field 45e is configured such that the rotational speed of the screw 330 at the time of the reversing operation can be input. The input field 45f is configured such that the delay time after the end of the reverse operation (before the start of the power failure operation) can be input.

The monitoring setting unit 46 has input fields 46a to 46c and display fields 46d. Here, the monitoring parameters during the purge operation are configured to be input. The input field 46a is configured so that the monitoring pressure during the charging operation can be input. If the pressure during the charging operation exceeds the monitoring pressure, the control device 700 determines that it is an error. The input field 46b is configured so that the monitoring time during the charging operation can be input. The control device 700 counts from the start of the charging operation, and determines that it is an error if the monitoring time is exceeded before the position of the screw 330 reaches the switching position of the V/P switching set in the input field 41b. .

The input field 46c is configured such that a torque monitoring range can be input. From the input value X input to the input field 46c, the torque monitoring range is set as a range of +X% to -X%. When the maximum torque at the time of rotation of the screw 330 exceeds the monitoring range, the control device 700 determines that it is an error. In the display field 46d, the detected value of the maximum rotation torque is displayed.

6 is a flowchart showing processing in a purging operation. However, in the following description, it is assumed that the retraction operation and the vibration operation are not performed, but the retraction operation and/or the vibration operation may be performed.

In step S101, the control device 700 drives the metering motor 340 based on the parameter set in the metering operation setting unit 43 to cause the screw 330 to be powered off, and the injection motor 350 It drives to control back pressure, and sends the molding material to the front.

In step S102, the control device 700 waits for a process for a delay time set by the input unit 75c. Accordingly, when the pressure of the molding material on the front side is higher than that of the screw head 332, the molding material flows backward through the groove 335, thereby reducing the pressure of the molding material on the front side than the screw head 332.

In step S103, the control device 700 drives the metering motor 340 to reverse the screw 330 based on the parameter set in the reverse power purge setting unit 45. When the screw 330 is reversed, the rear surface of the flight 334b receives a reaction force from the molding material, and a force is generated in the direction of advancing the screw 330. Here, the control device 700 controls the injection motor 350 so that the screw 330 maintains the current position (measured position). In other words, reverse back pressure is applied. Thereby, by friction between the back side of the flight 334b and the molding material, it is possible to remove the molding material or colorant adhered to the back side of the flight 334b. However, if the position of the screw 330 at the time of reversing the screw 330 is the forward limit position, the solid molding material supplied from the supply port 311 is attached to the root side of the screw 330. Materials or colorants can be removed. However, by applying the reverse back pressure in step S103, the friction between the back surface side of the flight 334b and the molding material may be promoted, and the screw 330 may slightly advance or retreat.

In step S104, the control device 700 waits for a process for a delay time set by the input unit 75f.

In step S105, the control device 700 drives the metering motor 340 to cause the screw 330 to be powered off based on the parameter set by the metering operation setting unit 43. When the screw 330 is electrostatically charged, the surface of the flight 334b receives a reaction force from the molding material, and a force is generated in the direction of retreating the screw 330. Here, the control device 700 controls the injection motor 350 so that the screw 330 maintains the current position (measured position). That is, back pressure is applied. Thereby, by friction between the front side of the flight 334b and the molding material, it is possible to remove the molding material or colorant adhering to the back side of the flight 334b. In addition, by setting the screw 330 to the forward limit position, it is possible to remove the adhering molding material or colorant to the root side of the screw 330 by the solid molding material supplied from the supply port 311. However, by applying back pressure in step S105, the friction between the surface side of the flight 334b and the molding material may be promoted, and the screw 330 may slightly advance or retreat.

In step S106, it is determined whether or not the repetition end condition has been satisfied. For example, when the reversing and reversing of the screw 330 is repeated a predetermined number of times, it is determined that the repetition end condition has been satisfied. If the repetition end condition is not satisfied (S106 No), the processing of the control device 700 returns to step S102. When the repetition end condition is satisfied (S106 YES), the processing of the control device 700 proceeds to step S107.

In step S107, the control device 700 drives the injection motor 350 to advance the screw 330 based on the parameter set in the filling operation setting unit 41, and the molding material from the inside of the cylinder 310 A discharge operation (charging operation) is performed. Hereinafter, the screw 330 will be described as being in the forward limit position.

In step S108, the control device 700 performs a holding pressure operation based on the parameter set in the holding pressure operation setting unit 42. However, the holding pressure operation is not essential and may not be required.

Hereinafter, the molding material in the cylinder 310 can be purged by repeating steps S101 to S108.

7 is a schematic cross-sectional view showing a state in the cylinder 310. However, in Fig. 7, the pressure of the molding material is schematically represented by the shade of halftone dots.

Fig. 7A shows the state in the cylinder 310 after the weighing operation S101. The backflow prevention ring 331 is disposed on the rear side of the head body portion 332a, and a flow path of the molding material formed between the backflow prevention ring 331 and the sealing ring 333 is opened. However, in each of the states shown in Figs. 7(b) to 7(g) shown below, the position of the backflow prevention ring 331 does not change significantly, and the front (left side of the ground) is It remains moving toward, and the flow path between the backflow prevention ring 331 and the sealing ring 333 maintains an open state. Further, in the metering step S101, the molding material is sent to the space in front of the screw head 332, so that the pressure of the molding material on the front side of the screw head 332 is increased.

The state in the cylinder 310 after waiting (S102) in FIG. 7B is shown. As indicated by the black arrow, the flight screw 334 passes through the flow path between the backflow prevention ring 331 and the sealing ring 333 from the space in front of the screw head 332 so as to eliminate the pressure difference. The molding material moves toward the side space. As a result, the pressure of the molding material on the front side of the screw head 332 is reduced.

Fig. 7C shows a state in the cylinder 310 at the time of the reversing operation (S103). By reversing the screw 330, the molding material moves backward as indicated by the black arrow. In addition, the pressure applied to the screw head 332 from the molding material is reduced because the pressure of the molding material on the front side of the screw head 332 has been previously lowered.

The state in the cylinder 310 after waiting (S104) in FIG. 7D is shown.

Fig. 7(e) shows a state in the cylinder 310 during the electrostatic operation (S105). By electrostaticizing the screw 330, the molding material moves forward as indicated by the black arrow. As a result, the pressure of the molding material on the front side of the screw head 332 increases.

Fig. 7(f) shows a state in the cylinder 310 after waiting (S106 No, S102). As indicated by the black arrow, the flight screw 334 passes through the flow path between the backflow prevention ring 331 and the sealing ring 333 from the space in front of the screw head 332 so as to eliminate the pressure difference. The molding material moves toward the side space. As a result, the pressure of the molding material on the front side of the screw head 332 is reduced.

7(g) shows the state inside the cylinder 310 in the reversing operation (S103). Here, by reversing the screw 330, the molding material moves backward as indicated by the black arrow. In addition, the pressure applied to the screw head 332 from the molding material is reduced because the pressure of the molding material on the front side of the screw head 332 has been previously lowered. Hereinafter, FIG. 7(d)-FIG. 7(g) are repeated.

As described above, according to the injection molding machine 10 according to the present embodiment, by reversing the screw 330 and applying reverse back pressure to the screw 330, a molding material or a colorant adhered to the back side of the flight 334b is suitable. Can be removed. Further, by repeating the forward/reverse of the screw 330, the molding material moves back and forth in the cylinder 310, so that the molding material or the colorant adhering to the inner wall of the cylinder 310 can be suitably removed.

Further, in step S102, the pressure of the molding material on the front side of the screw head 332 is reduced. Thereby, when the screw 330 is reversed in step S103, the torque received by the screw head 332 from the molding material can be reduced, and loosening of the screw head 332 can be suppressed.

Further, the control device 700 monitors the charging pressure based on the parameter set in the monitoring setting unit 46. Here, when the filling pressure increases, the torque that the screw head 332 receives from the molding material when the screw 330 is reversed also increases. By monitoring the filling pressure, it is possible to monitor the fear of loosening of the screw head 332.

Further, the control device 700 monitors the torque of the screw 330 based on the parameter set in the monitoring setting unit 46. By monitoring the torque of the screw 330, it is possible to monitor the fear of loosening of the screw head 332.

As described above, embodiments and the like of the injection molding machine have been described, but the present invention is not limited to the above embodiments and the like, and various modifications and improvements are possible within the scope of the gist of the present invention described in the claims.

In step S102, the pressure of the molding material on the front side of the screw head 332 is lowered by waiting for the processing during the delay time, but the present invention is not limited thereto. The control device 700 may drive the injection motor 350 to retreat the screw 330. In addition, both delay and retreat may be performed. That is, after waiting for the processing until the delay time elapses, the screw 330 may be retracted again. Further, after the screw 330 is retracted, the processing may be waited until the delay time elapses. In addition, delay and retreat may be alternately repeated. When the screw 330 is retracted, the control device 700 may control the metering motor 340 so that the screw 330 maintains the current rotation angle. Accordingly, it is possible to reduce the pressure of the molding material in front of the screw head 332 before the reversing operation of the screw 330. The screw 330 is sequentially retreated while repeating the reversing operation and the power failure operation of the screw 330 shown in steps S102 to S106. Then, at the beginning of the charging operation (S107), the screw 330 may be advanced to return to the initial position (measurement completion position). Further, the charging operation (S107) may be started from the position where the screw 330 is retracted.

In addition, after the weighing operation shown in step S101, the process of repeating the reversing operation and the power failure operation of the screw 330 shown in steps S102 to S106 is performed, but the description is not limited thereto. During the weighing operation, the reversing operation and the power failure operation may be performed.

That is, after the filling operation and the holding pressure operation of steps S107 and S108 are finished, step S101 is skipped, and the control device 700 waits for a delay time to reduce the pressure of the molding material on the front side of the screw head 332. (S102). The control device 700 performs a reversing operation (S103) at the forward limit position of the screw 330. The control device 700 waits for a delay time (S104).

Next, the control device 700 also performs a weighing operation during the power failure operation (S105). That is, in step S105, the control device 700 drives the metering motor 340 based on the parameter set in the metering operation setting unit 43 to cause the screw 330 to power out, and the injection motor 350 ) Is driven to control the back pressure, and the screw 330 is retracted, and the molding material is sent to the front. Here, the total stroke amount St of the screw 330 in the weighing operation (the measurement completion position set in the input field 43b) is divided by the number of divisions N (the number of divisions set in the input field 45b). When the screw 330 has retreated St/N, the process proceeds to step S106.

In step S106, it is determined whether or not the repetition end condition has been satisfied. Here, when the screw 330 reaches the weighing completion position, it is determined that the repeating end condition has been satisfied. If the repetition end condition is not satisfied (S106 No), the processing of the control device 700 returns to step S102.

Next, the control device 700 waits for a delay time and lowers the pressure of the molding material in front of the screw head 332 (S102). In the control device 700, the screw 330 performs a reversing operation (S103) at the position of St/N. The control device 700 waits for a delay time (S104). The control device 700 performs a power failure operation (S105), and the screw 330 is further retreated by St/N.

Hereinafter, while repeating the reversing operation and the power failure operation, the screw 330 is moved to the measurement completion position. That is, the operation of retreating the screw 330 while repeating the reversing operation and the power failure operation shown in steps S102 to S106 corresponds to the weighing operation S101. When the weighing completion position is reached (S106 YES), the process proceeds to the charging operation and the holding pressure operation of steps S107 and S108.

According to this, since the reverse operation and the power failure operation can be repeated during the weighing operation, the processing time can be shortened.

10 Injection molding machine
300 injection device
310 cylinder
311 supply port
313 burner
320 nozzle
330 screw
331 Backflow prevention ring
332 screw head
332a head body part
332b rod
333 sealing
334 flight screw
334a rotary shaft
334b flight
335 home
340 metering motor (drive part)
350 injection motor (drive part)
360 pressure detector
700 control unit (control unit)
30 display screen
40 display area
41 Charging operation setting part
42 Hold pressure operation setting part
43 Weighing operation setting part
44 Vibration operation setting part
45 Reverse purge setting unit
46 Monitoring setting part

Claims (8)

A cylinder for heating the molding material,
A nozzle provided at the front end of the cylinder,
A screw that is rotatably and retractably disposed in the cylinder,
A driving unit for driving the screw,
And a control unit for controlling the driving unit,
The control unit,
Lowering the pressure of the molding material on the nozzle side than the screw in the cylinder,
An injection molding machine that rotates the screw. The method of claim 1,
The screw is rotatable in a first rotational direction for sending the molding material in a direction of the nozzle and a second rotational direction opposite to the first rotational direction. The method of claim 2,
When the screw is rotated in the second rotational direction, the injection molding machine maintains a position of the screw in the advancing and retreating direction. The method according to claim 2 or 3,
When rotating the screw in the first rotation direction,
An injection molding machine that maintains the position of the screw in the forward and backward direction. The method according to claim 2 or 3,
When rotating the screw in the first rotation direction,
An injection molding machine for retracting the screw. The method according to any one of claims 1 to 3,
The screw,
A flight screw on which a flight is formed,
It has a screw head provided at the front end of the flight screw,
The screw head is inserted into and fixed to the flight screw, an injection molding machine. The method according to any one of claims 1 to 3,
The control unit,
An injection molding machine, wherein the pressure of the molding material on the nozzle side is lowered than that of the screw by waiting for the screw for a predetermined time. The method according to any one of claims 1 to 3,
The control unit,
An injection molding machine in which the pressure of the molding material on the nozzle side is lowered than that of the screw by retreating the screw.

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