Display device for injection molding machine, control device for injection molding machine, and injection molding machine

Abstract

To provide a technique enabling a setting of an injection process to be switched according to a molding article.SOLUTION: A display device is for an injection molding machine including: an injection member disposed inside a cylinder configured to heat a molding material; and an injection driving source configured to advance the injection member to fill the molding material inside a mold device. The display device displays, in an injection process configured to control a speed of the injection member or a pressure acting from the injection member on the molding material during a retreat of the injection member, a screen having a selection part configured to accept a selection to execute which one of: a retreat speed control configured to control an actual speed value of the injection member to be a first set value and a retreat speed limit configured to limit the actual speed value of the injection member to be a second set value or lower.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a display device of an injection molding machine, a control device of an injection molding machine, and an injection molding machine.

Background Art

[0002] An injection molding machine includes an injection member provided inside a cylinder for heating a molding material, an injection drive source for filling the molding material into a mold device by advancing the injection member, and a control device for controlling the injection drive source (see, for example, Patent Document 1). The injection member is, for example, a screw. The screw is provided inside the cylinder so as to be rotatable and movable forward and backward.

[0003] The control device performs a filling process and a holding pressure process in this order. The filling process is a process of filling the molding material into the mold device by controlling the injection drive source so that the actual value of the moving speed of the injection member becomes the set value. The holding pressure process is a process of replenishing the insufficient molding material due to cooling shrinkage in the mold device by controlling the injection drive source so that the actual pressure value acting on the molding material from the injection member becomes the pressure set value.

[0004] The switching from the filling process to the holding pressure process is also called V / P switching. Immediately after the V / P switching, if the actual pressure value is larger than the pressure set value, the injection member is retracted so that the actual pressure value becomes smaller. Patent Document 1 describes that by setting a limit value for the retraction speed of the injection member in the holding pressure process, it is possible to eliminate the adverse effect on the quality of the molded product due to the high-speed retraction of the injection member immediately after the V / P switching.

Prior Art Documents

Patent Documents

[0005] <0​​​​​​​​​​

[0006] Molded products are obtained by filling the cavity space inside the mold device with molding material and allowing it to solidify. In order to eliminate adverse effects on the quality of the molded product, Patent Document 1 describes a retraction speed limit that restricts the actual speed of the injection member to below a set value while the injection member is retracting.

[0007] However, depending on the molded product, a different control method may be required instead of limiting the retraction speed. For example, if the molded product is thin, retraction speed control is required to control the actual speed of the injection member to a set value while the injection member is retracting.

[0008] When the thickness of the molded product is thin, the forward speed of the injection member is set to be fast during the filling process to prevent the flow of the molding material from stopping midway. This results in high resin pressure at the entrance of the cavity space.

[0009] Thus, when the forward speed of the injection member is set to a high speed during the filling process, it is necessary to release the resin pressure by controlling the retraction speed to prevent the molded product from warping due to uneven distribution of residual stress.

[0010] One aspect of the present invention provides a technology that allows the settings of the injection process to be switched according to the molded product. [Means for solving the problem]

[0011] A display device according to one aspect of the present invention is a display device for an injection molding machine comprising an injection member provided inside a cylinder for heating a molding material, and an injection drive source for filling the molding material into the inside of a mold device by advancing the injection member. The display device displays a screen having a selection section that accepts a selection of whether to perform retraction speed control, which controls the actual speed value of the injection member to a first set value, or retraction speed limiting, which limits the actual speed value of the injection member to a second set value or less, during the retraction of the injection member. [Effects of the Invention]

[0012] According to one aspect of the present invention, the settings for the injection process can be switched according to the molded product by displaying a screen having a selection unit that accepts the selection of whether to implement reversal speed control or reversal speed limiting. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 shows the state of an injection molding machine upon completion of mold opening according to one embodiment. [Figure 2] Figure 2 shows the state of an injection molding machine during mold clamping according to one embodiment. [Figure 3] Figure 3 is a diagram showing an example of the components of a control device in terms of functional blocks. [Figure 4] Figure 4 shows an example of the molding cycle process. [Figure 5] Figure 5 shows an example of an injection control unit. [Figure 6] Figure 6 shows an example of a speed command correction unit. [Figure 7] Figure 7(A) shows an example of the screen when reverse speed control is selected, and Figure 7(B) shows an example of the screen when reverse speed limit is selected. [Figure 8] Figure 8 shows an example of the time evolution of screw speed, pressure, and screw position when retraction speed control is selected. [Modes for carrying out the invention]

[0014] Embodiments of the present invention will be described below with reference to the drawings. In each drawing, the same or corresponding components are denoted by the same reference numerals, and their descriptions may be omitted.

[0015] (injection molding machine) FIG. 1 is a diagram showing the state of an injection molding machine at the completion of mold opening in one embodiment. FIG. 2 is a diagram showing the state of the injection molding machine when the mold is clamped. In this specification, the X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other. The X-axis direction and the Y-axis direction represent the horizontal direction, and the Z-axis direction represents the vertical direction. When the mold clamping device 100 is a horizontal mold, 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 non-operation side.

[0016] As shown in FIGS. 1 to 2, the injection molding machine 10 includes a mold clamping device 100 that opens and closes the mold device 800, an ejector device 200 that ejects the molded product formed 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 forward and backward with respect to the mold device 800, a control device 700 that controls each component of the injection molding machine 10, and a frame 900 that supports each component of the injection molding machine 10. The frame 900 includes a mold clamping device frame 910 that supports the mold clamping device 100 and an injection device frame 920 that supports the injection device 300. The mold clamping device frame 910 and the injection device frame 920 are respectively installed on the floor 2 via leveling adjusters 930. The control device 700 is disposed in the internal space of the injection device frame 920. Hereinafter, each component of the injection molding machine 10 will be described.

[0017] (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 positive X-axis direction) is described as the front, and the moving direction of the movable platen 120 when the mold is opened (for example, the negative X-axis direction) is described as the rear.

[0018] <0000第一の実施形態において、エジェクタ装置200は、エジェクタピン210と、エジェクタピン210を移動させるエジェクタシリンダ220とを有する。エジェクタピン210は、可動金型820に形成されたエジェクタ穴822に挿入される。エジェクタシリンダ220は、エジェクタピン210を後退させることにより、金型装置800で成形された成形品を突き出す。

[0019] ​The clamping device 100 is, for example, horizontal, and the mold opening / closing direction is horizontal. The clamping device 100 includes a fixed platen 110 to which a fixed mold 810 is attached, a movable platen 120 to which a movable mold 820 is attached, and a moving mechanism 102 that moves the movable platen 120 in the mold opening / closing direction with respect to the fixed platen 110.

[0020] The fixed platen 110 is fixed to the clamping device frame 910. The fixed mold 810 is attached to the opposing surface of the fixed platen 110 with respect to the movable platen 120.

[0021] The movable platen 120 is disposed movably in the mold opening / closing direction with respect to the clamping device frame 910. A guide 101 for guiding the movable platen 120 is laid on the clamping device frame 910. The movable mold 820 is attached to the opposing surface of the movable platen 120 with respect to the fixed platen 110.

[0022] The moving mechanism 102 performs mold closing, pressure boosting, mold clamping, pressure release, and mold opening of the mold device 800 by advancing and retreating the movable platen 120 with respect to the fixed platen 110. The moving mechanism 102 includes a toggle support 130 disposed at an interval from the fixed platen 110, a tie bar 140 connecting the fixed platen 110 and the toggle support 130, a toggle mechanism 150 that moves the movable platen 120 in the mold opening / closing direction with respect to the toggle support 130, a clamping motor 160 that operates the toggle mechanism 150, a motion conversion mechanism 170 that converts the rotational motion of the clamping motor 160 into a linear motion, and a mold thickness adjustment mechanism 180 that adjusts the interval between the fixed platen 110 and the toggle support 130.

[0023] The toggle support 130 is disposed at an interval from the fixed platen 110 and is placed movably in the mold opening / closing direction on the clamping device frame 910. Incidentally, the toggle support 130 may be disposed movably along a guide laid 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.

[0024] In this embodiment, the fixed platen 110 is fixed to the clamping device frame 910, and the toggle support 130 is arranged to be movable relative to the clamping device frame 910 in the mold opening and closing direction. However, the toggle support 130 may be fixed to the clamping device frame 910, and the fixed platen 110 may be arranged to be movable relative to the clamping device frame 910 in the mold opening and closing direction.

[0025] The tie bars 140 connect the fixed platen 110 and the toggle support 130 at a distance L in the mold opening and closing direction. Multiple tie bars 140 (for example, four) may be used. Multiple tie bars 140 are arranged parallel to the mold opening and closing direction and stretch in accordance with the clamping force. At least one tie bar 140 may be provided with a tie bar strain detector 141 that detects the strain of the tie bar 140. The tie bar strain detector 141 sends a signal indicating its detection result to the control device 700. The detection result of the tie bar strain detector 141 is used for detecting the clamping force, etc.

[0026] In this embodiment, a tie bar strain detector 141 is used as a clamping force detector to detect the clamping force, but the present invention is not limited to this. The clamping force detector is not limited to strain gauge type, but may be piezoelectric, capacitive, hydraulic, electromagnetic, etc., and its mounting position is not limited to the tie bar 140.

[0027] The toggle mechanism 150 is positioned between the movable platen 120 and the toggle support 130, and moves the movable platen 120 in the mold opening and closing direction relative to the toggle support 130. The toggle mechanism 150 has a crosshead 151 that moves in the mold opening and closing direction, and a pair of link groups that bend and extend as the crosshead 151 moves. Each of the link groups has a first link 152 and a second link 153 that are bendable and extendable connected by a pin or the like. The first link 152 is pivotably attached to the movable platen 120 by a pin or the like. The second link 153 is pivotably attached to the toggle support 130 by a pin or the like. The second link 153 is attached to the crosshead 151 via a third link 154. When the crosshead 151 moves forward and backward relative to the toggle support 130, the first link 152 and the second link 153 bend and extend, and the movable platen 120 moves forward and backward relative to the toggle support 130.

[0028] Furthermore, the configuration of the toggle mechanism 150 is not limited to the configuration shown in Figures 1 and 2. For example, in Figures 1 and 2, each link group has five nodes, but it may also have four, and one end of the third link 154 may be connected to the node between the first link 152 and the second link 153.

[0029] The clamping motor 160 is attached to the toggle support 130 and operates the toggle mechanism 150. The clamping motor 160 moves the crosshead 151 forward and backward relative to the toggle support 130, thereby bending and extending the first link 152 and the second link 153, and moving the movable platen 120 forward and backward relative to the toggle support 130. The clamping motor 160 is directly connected to the motion conversion mechanism 170, but it may also be connected to the motion conversion mechanism 170 via a belt, pulley, or the like.

[0030] The motion conversion mechanism 170 converts the rotational motion of the clamping motor 160 into the linear motion of the crosshead 151. The motion conversion mechanism 170 includes a screw shaft and a screw nut that screws onto the screw shaft. A ball or roller may be interposed between the screw shaft and the screw nut.

[0031] The mold clamping device 100 performs processes such as mold closing, pressure boosting, mold clamping, depressurization, and mold opening under the control of the control device 700.

[0032] In the mold closing process, the clamping motor 160 is driven to advance the crosshead 151 to the mold closing completion position at a 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 movement speed of the crosshead 151 are detected using, for example, a clamping motor encoder 161. 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.

[0033] Furthermore, the crosshead position detector for detecting the position of the crosshead 151 and the crosshead speed detector for detecting the movement speed of the crosshead 151 are not limited to the clamping motor encoder 161, and general-purpose devices can be used. Similarly, the movable platen position detector for detecting the position of the movable platen 120 and the movable platen speed detector for detecting the movement speed of the movable platen 120 are not limited to the clamping motor encoder 161, and general-purpose devices can be used.

[0034] In the boosting process, the clamping motor 160 is further driven to advance the crosshead 151 from the closed position to the clamping position, thereby generating clamping force.

[0035] In the clamping process, the clamping motor 160 is driven to maintain the position of the crosshead 151 in the clamping position. In the clamping process, the clamping force generated in the pressurization process is maintained. In the clamping process, a cavity space 801 (see Figure 2) is formed between the movable mold 820 and the fixed mold 810, and the injection unit 300 fills the cavity space 801 with liquid molding material. A molded product is obtained when the filled molding material solidifies.

[0036] The number of cavity spaces 801 may be one or more. In the latter case, multiple molded products can be obtained simultaneously. An insert material may be placed in part of the cavity space 801, and the molding material may be filled in the other part of the cavity space 801. A molded product in which the insert material and the molding material are integrated is obtained.

[0037] In the depressurization process, the clamping motor 160 is driven to retract the crosshead 151 from the clamping position to the mold opening start position, thereby retracting the movable platen 120 and reducing the clamping force. The mold opening start position and the mold closing completion position may be the same position.

[0038] In the mold opening process, the 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. Subsequently, the ejector device 200 ejects the molded product from the movable mold 820.

[0039] The setting conditions for the mold closing process, the pressure boosting process, and the mold clamping process are set together as a series of setting conditions. For example, the movement speed and position of the crosshead 151 (including the mold closing start position, movement speed switching position, mold closing completion position, and mold clamping position), and the mold clamping force in the mold closing process and the pressure boosting process are set together as a series of setting conditions. The mold closing start position, movement speed switching position, mold closing completion position, and mold clamping position are arranged in this order from rear to front and represent the start and end points of the section in which the movement speed is set. The movement speed is set for each section. There may be one or more movement speed switching positions. There may be no movement speed switching positions. The mold clamping position and the mold clamping force may be set individually or individually.

[0040] The setting conditions for the depressurization process and the mold opening process are set similarly. For example, the movement speed and position of the crosshead 151 in the depressurization process and the mold opening process (mold opening start position, movement speed switching position, and mold opening completion position) are set together as a series of setting conditions. The mold opening start position, movement speed switching position, and mold opening completion position are arranged in this order from front to back and represent the start and end points of the sections in which the movement speed is set. The movement speed is set for each section. There may be one or more movement speed switching positions. There may be no movement speed switching positions. 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.

[0041] Furthermore, instead of the movement speed and position of the crosshead 151, the movement speed and position of the movable platen 120 may be set. Also, instead of the position of the crosshead (e.g., the clamping position) or the position of the movable platen, the clamping force may be set.

[0042] Incidentally, the toggle mechanism 150 amplifies the driving force of the clamping motor 160 and transmits it to the movable platen 120. This amplification ratio is also called the toggle ratio. The toggle ratio changes depending on the angle θ between the first link 152 and the second link 153 (hereinafter also referred to as the "link angle θ"). The link angle θ can be determined from the position of the crosshead 151. The toggle ratio is maximized when the link angle θ is 180°.

[0043] If the thickness of the mold device 800 changes due to replacement of the mold device 800 or a change in the temperature of the mold device 800, the mold thickness is adjusted so that a predetermined clamping force is obtained during mold clamping. In mold thickness adjustment, for example, the distance L between the fixed platen 110 and the toggle support 130 is adjusted so that the link angle θ of the toggle mechanism 150 becomes a predetermined angle at the time of mold touch when the movable mold 820 touches the fixed mold 810.

[0044] The mold clamping device 100 has a mold thickness adjustment mechanism 180. The mold thickness adjustment mechanism 180 adjusts the mold thickness by adjusting the distance L between the fixed platen 110 and the toggle support 130. The timing of the mold thickness adjustment is, for example, between the end of one molding cycle and 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, a screw nut 182 that is rotatably and immovably held by the toggle support 130, and a mold thickness adjustment motor 183 that rotates the screw nut 182 that is screwed onto the screw shaft 181.

[0045] A screw shaft 181 and screw nut 182 are provided for each tie bar 140. The rotational driving force of the mold thickness adjustment motor 183 may be transmitted to multiple screw nuts 182 via a rotational driving force transmission unit 185. Multiple screw nuts 182 can be rotated synchronously. It is also possible to rotate multiple screw nuts 182 individually by changing the transmission path of the rotational driving force transmission unit 185.

[0046] The rotational drive force transmission unit 185 is composed of, for example, gears. In this case, driven gears are formed on the outer circumference of each screw nut 182, a drive gear is attached to the output shaft of the mold thickness adjustment motor 183, and an intermediate gear that meshes with the multiple driven gears and the drive gear is rotatably held in the center of the toggle support 130. Note that the rotational drive force transmission unit 185 may be composed of a belt or pulley instead of gears.

[0047] The operation of the mold thickness adjustment mechanism 180 is controlled by the control device 700. The control device 700 drives the mold thickness adjustment motor 183 to rotate the screw nut 182. As a result, the position of the toggle support 130 relative to the tie bar 140 is adjusted, and the distance L between the fixed platen 110 and the toggle support 130 is adjusted. Multiple mold thickness adjustment mechanisms may be used in combination.

[0048] The interval L is detected using the mold thickness adjustment motor encoder 184. The mold thickness adjustment motor encoder 184 detects the amount and direction of rotation of the mold thickness adjustment motor 183 and sends a signal indicating the detection result to the control device 700. The detection result of the mold thickness adjustment motor encoder 184 is used to monitor and control the position and interval L of the toggle support 130. Note that the toggle support position detector for detecting the position of the toggle support 130 and the interval detector for detecting the interval L are not limited to the mold thickness adjustment motor encoder 184, but general-purpose devices can be used.

[0049] The clamping device 100 may have a mold temperature controller that adjusts the temperature of the mold device 800. The mold device 800 has a flow path for a temperature-controlled medium inside it. The mold temperature controller adjusts the temperature of the mold device 800 by adjusting the temperature of the temperature-controlled medium supplied to the flow path of the mold device 800.

[0050] In this embodiment, the mold clamping device 100 is a horizontal type in which the mold opening and closing direction is horizontal, but it may also be a vertical type in which the mold opening and closing direction is vertical.

[0051] In this embodiment, the clamping device 100 has a clamping motor 160 as a drive unit, but a hydraulic cylinder may be used instead of the clamping motor 160. Furthermore, the clamping device 100 may have a linear motor for opening and closing the mold, and an electromagnet for clamping the mold.

[0052] (Ejector device) In describing the ejector device 200, similar to the description of the clamping device 100, the direction of movement of the movable platen 120 when the mold is closed (for example, the positive X-axis direction) is described as forward, and the direction of movement of the movable platen 120 when the mold is open (for example, the negative X-axis direction) is described as backward.

[0053] The ejector device 200 is attached to the movable platen 120 and moves back and forth together with the movable platen 120. The ejector device 200 includes an ejector rod 210 that ejects the molded product from the mold device 800 and a drive mechanism 220 that moves the ejector rod 210 in the direction of movement of the movable platen 120 (in the X-axis direction).

[0054] The ejector rod 210 is positioned to move back and forth within a through-hole in the movable platen 120. The front end of the ejector rod 210 contacts the ejector plate 826 of the movable mold 820. The front end of the ejector rod 210 may or may not be connected to the ejector plate 826.

[0055] The drive mechanism 220 includes, for example, an ejector motor and a motion conversion mechanism that converts the rotational motion of the ejector motor into the linear motion of the ejector rod 210. The motion conversion mechanism includes a screw shaft and a screw nut that screws onto the screw shaft. A ball or roller may be interposed between the screw shaft and the screw nut.

[0056] The ejector device 200 performs the ejection process under the control of the control device 700. In the ejection process, the ejector rod 210 is advanced from the standby position to the ejection position at a set travel speed, thereby advancing the ejector plate 826 and ejecting the molded product. Subsequently, the ejector motor is driven to retract the ejector rod 210 at a set travel speed, retracting the ejector plate 826 back to its original standby position.

[0057] The position and speed of the ejector rod 210 are detected, for example, using an ejector motor encoder. The ejector motor encoder detects the rotation of the ejector motor and sends a signal indicating the detection result to the control device 700. Note that the ejector rod position detector, which detects the position of the ejector rod 210, and the ejector rod speed detector, which detects the speed of the ejector rod 210, are not limited to ejector motor encoders, but general-purpose devices can be used.

[0058] (injection device) In the description of the injection device 300, unlike the descriptions of the clamping device 100 and the ejector device 200, the direction of movement of the screw 330 during filling (for example, the negative X-axis direction) is described as forward, and the direction of movement of the screw 330 during metering (for example, the positive X-axis direction) is described as backward.

[0059] The injection device 300 is mounted on a slide base 301, which is positioned to move back and forth relative to the injection device frame 920. The injection device 300 is positioned to move back and forth relative to the mold device 800. The injection device 300 touches the mold device 800 and fills the cavity space 801 within the mold device 800 with molding material. The injection device 300 includes, for example, a cylinder 310 for heating the molding material, a nozzle 320 provided at the front end of the cylinder 310, a screw 330 positioned within the cylinder 310 to move back and forth and to rotate, a metering motor 340 for rotating the screw 330, an injection motor 350 for moving the screw 330 back and forth, and a load detector 360 for detecting the load transmitted between the injection motor 350 and the screw 330.

[0060] Cylinder 310 heats the molding material supplied to its interior from the supply port 311. The molding material includes, for example, resin. The molding material is formed, for example, into pellets and supplied to the supply port 311 in a solid state. The supply port 311 is formed at the rear of cylinder 310. A cooler 312, such as a water-cooled cylinder, is provided on the outer circumference of the rear of cylinder 310. In front of the cooler 312, a first heater 313, such as a band heater, and a first temperature detector 314 are provided on the outer circumference of cylinder 310.

[0061] The cylinder 310 is divided into multiple zones along its axial direction (for example, the X-axis direction). A first heater 313 and a first temperature detector 314 are provided in each of the multiple zones. A set temperature is set for each of the multiple zones, and the control device 700 controls the first heater 313 so that the temperature detected by the first temperature detector 314 becomes the set temperature.

[0062] The nozzle 320 is located at the front end of the cylinder 310 and is pressed against the mold device 800. A second heater 323 and a second temperature detector 324 are provided on the outer circumference of the nozzle 320. The control device 700 controls the second heater 323 so that the detected temperature of the nozzle 320 reaches a set temperature.

[0063] The screw 330 is rotatably and reciprocally positioned within the cylinder 310. When the screw 330 is rotated, the molding material is fed forward along the helical groove of the screw 330. As the molding material is fed forward, it is gradually melted by the heat from the cylinder 310. As the liquid molding material is fed forward to the screw 330 and accumulates at the front of the cylinder 310, the screw 330 is retracted. Then, 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 device 800.

[0064] A backflow prevention ring 331 is mounted on the front of the screw 330 so as to be able to move back and forth, acting as a backflow prevention valve to prevent backflow of the molding material from the front to the rear of the screw 330 when the screw 330 is pushed forward.

[0065] When the screw 330 is advanced, the backflow prevention ring 331 is pushed backward by the pressure of the molding material in front of the screw 330, and retracts relative to the screw 330 to a closed position (see Figure 2) that blocks the flow path of the molding material. This prevents the molding material accumulated in front of the screw 330 from flowing backward.

[0066] On the other hand, when the screw 330 is rotated, the backflow prevention ring 331 is pushed forward by the pressure of the molding material being sent forward along the helical groove of the screw 330, and moves relative to the screw 330 to an open position (see Figure 1) that opens the flow path of the molding material. As a result, the molding material is sent forward of the screw 330.

[0067] The backflow prevention ring 331 may be either a co-rotating type that rotates together with the screw 330, or a non-co-rotating type that does not rotate together with the screw 330.

[0068] Furthermore, the injection device 300 may have a drive source that moves the backflow prevention ring 331 back and forth between an open position and a closed position relative to the screw 330.

[0069] The metering motor 340 rotates the screw 330. The drive source for rotating the screw 330 is not limited to the metering motor 340; for example, a hydraulic pump or the like may also be used.

[0070] The injection motor 350 moves the screw 330 forward and backward. Between the injection motor 350 and the screw 330, there is a motion conversion mechanism that converts the rotational motion of the injection motor 350 into the linear motion of the screw 330. The motion conversion mechanism has, for example, a screw shaft and a screw nut that screws onto the screw shaft. Balls or rollers may be provided between the screw shaft and the screw nut. The drive source for moving the screw 330 forward and backward is not limited to the injection motor 350, but may also be, for example, a hydraulic cylinder.

[0071] The load detector 360 detects the load transmitted between the injection motor 350 and the screw 330. The detected load is converted into pressure by the control device 700. The load detector 360 is installed in the load transmission path between the injection motor 350 and the screw 330 and detects the load acting on the load detector 360.

[0072] The load detector 360 sends a signal of the detected load to the control device 700. The load detected by the load detector 360 is converted into pressure acting between the screw 330 and the molding material, and is used for controlling and monitoring the pressure the screw 330 receives from the molding material, the back pressure on the screw 330, and the pressure acting from the screw 330 on the molding material.

[0073] Furthermore, the pressure detector used to detect the pressure of the molding material is not limited to the load detector 360, but a general-purpose one can be used. For example, a nozzle pressure sensor or an in-mold pressure sensor may be used. The nozzle pressure sensor is installed in the nozzle 320. The in-mold pressure sensor is installed inside the mold device 800.

[0074] The injection device 300 performs processes such as metering, filling, and holding pressure under the control of the control device 700. The filling and holding pressure processes may be collectively referred to as the injection process.

[0075] In the metering process, the metering motor 340 is driven to rotate the screw 330 at a set rotational speed, and the molding material is fed forward along the helical groove of the screw 330. As this occurs, the molding material is gradually melted. As the liquid molding material is fed forward by the screw 330 and accumulates at the front of the cylinder 310, the screw 330 is retracted. The rotational speed of the screw 330 is detected, for example, using 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. Note that the screw rotational speed detector for detecting the rotational speed of the screw 330 is not limited to the metering motor encoder 341, and a general-purpose one can be used.

[0076] In the weighing process, the injection motor 350 may be driven to apply a set back pressure to the screw 330 in order to limit the rapid retraction of the screw 330. The back pressure on the screw 330 is detected, for example, using a load detector 360. The weighing process is completed when the screw 330 has retracted to the weighing completion position and a predetermined amount of molding material has accumulated in front of the screw 330.

[0077] The position and rotational speed of the screw 330 in the metering process are set together as a series of setting conditions. For example, the metering start position, rotational speed switching position, and metering completion position are set. These positions are arranged in this order from front to back and represent the start and end points of the sections in which the rotational speed is set. The rotational speed is set for each section. There may be one or more rotational speed switching positions. The rotational speed switching positions may not be set. In addition, back pressure is set for each section.

[0078] In the filling process, the injection motor 350 is driven to advance the screw 330 at a set speed, filling the cavity space 801 in the mold device 800 with the liquid molding material accumulated in front of the screw 330. The position and speed of the screw 330 are detected, for example, using 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, a switchover from the filling process to the holding pressure process (so-called V / P switching) occurs. The position at which the V / P switching occurs is also called the V / P switching position. The set speed of the screw 330 may be changed depending on the position and time of the screw 330.

[0079] The position and movement speed of the screw 330 during the filling process are set together as a series of setting conditions. For example, the filling start position (also called the "injection start position"), the movement speed switching position, and the V / P switching position are set. These positions are arranged in this order from rear to front and represent the start and end points of the sections in which the movement speed is set. The movement speed is set for each section. There may be one or more movement speed switching positions. The movement speed switching positions may not be set at all.

[0080] For each section in which the movement speed of the screw 330 is set, an upper limit is set for the pressure of the screw 330. The pressure of the screw 330 is detected by the load sensor 360. If the pressure of the screw 330 is below the set pressure, the screw 330 moves forward at the set movement speed. On the other hand, if the pressure of the screw 330 exceeds the set pressure, for the purpose of protecting the mold, the screw 330 moves forward at a slower movement speed than the set movement speed so that the pressure of the screw 330 becomes below the set pressure.

[0081] Furthermore, during the filling process, after the screw 330 reaches the V / P switching position, the screw 330 may be temporarily stopped at the V / P switching position, and then the V / P switching may be performed. Immediately before the V / P switching, instead of stopping the screw 330, the screw 330 may be moved forward or backward at a slow speed. In addition, the screw position detector that detects the position of the screw 330 and the screw movement speed detector that detects the movement speed of the screw 330 are not limited to the injection motor encoder 351, but general-purpose ones can be used.

[0082] In the holding pressure process, the injection motor 350 is driven to push the screw 330 forward, maintaining 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, and pushing the molding material remaining in the cylinder 310 toward the mold device 800. This allows for the replenishment of molding material lost due to cooling shrinkage within the mold device 800. The holding pressure is detected, for example, using a load detector 360. The set value of the holding pressure may be changed according to the elapsed time from the start of the holding pressure process. Multiple holding pressures and holding times for maintaining the holding pressure in the holding pressure process may be set, and may be set together as a series of setting conditions.

[0083] During the holding pressure process, the molding material in the cavity space 801 within the mold device 800 is gradually cooled, and upon completion of the holding pressure process, the entrance to the cavity space 801 is sealed with solidified molding material. This state is called a gate seal, and prevents backflow of molding material from the cavity space 801. After the holding pressure process, the cooling process begins. During the cooling process, the molding material in the cavity space 801 is solidified. To shorten the molding cycle time, a metering process may be performed during the cooling process.

[0084] In this embodiment, the injection device 300 is an in-line screw type, but a pre-plasticization type or the like may also be used. In a pre-plasticization injection device, the molding material molten in a plasticizing cylinder is supplied to the injection cylinder, and the molding material is injected from the injection cylinder into the mold device. In the plasticizing cylinder, a screw is arranged to be rotatable but unable to move back and forth, or a screw is arranged to be rotatable and able to move back and forth. On the other hand, a plunger is arranged to be able to move back and forth in the injection cylinder.

[0085] Furthermore, although the injection device 300 in this embodiment is a horizontal type with the axial direction of the cylinder 310 being horizontal, it may also be a vertical type with the axial direction of the cylinder 310 being vertical. The clamping device combined with the vertical injection device 300 may be vertical or horizontal. Similarly, the clamping device combined with the horizontal injection device 300 may be horizontal or vertical.

[0086] (Mobile device) In describing the moving device 400, similar to the description of the injection device 300, the direction of movement of the screw 330 during filling (for example, the negative X-axis direction) is described as forward, and the direction of movement of the screw 330 during metering (for example, the positive X-axis direction) is described as backward.

[0087] The moving device 400 moves the injection device 300 forward and backward relative to the mold device 800. The moving device 400 also presses the nozzle 320 against the mold device 800, generating 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.

[0088] The hydraulic pump 410 has a first port 411 and a second port 412. The hydraulic pump 410 is a bidirectional pump, and by switching the rotation direction of the motor 420, it can draw in working fluid (e.g., oil) from either the first port 411 or the second port 412 and discharge it from the other to generate hydraulic pressure. The hydraulic pump 410 can also draw working fluid from a tank and discharge it from either the first port 411 or the second port 412.

[0089] Motor 420 operates the hydraulic pump 410. Motor 420 drives the hydraulic pump 410 with a rotational direction and rotational torque corresponding to the control signal from the control device 700. Motor 420 may be an electric motor or an electric servo motor.

[0090] The hydraulic cylinder 430 comprises a cylinder body 431, a piston 432, and a piston rod 433. The cylinder body 431 is fixed to the injection device 300. The piston 432 divides the inside of the cylinder body 431 into a front chamber 435 as a first chamber and a rear chamber 436 as a second chamber. The piston rod 433 is fixed to the fixed platen 110.

[0091] The front chamber 435 of the hydraulic cylinder 430 is connected to the first port 411 of the hydraulic pump 410 via a first passage 401. The hydraulic fluid discharged from the first port 411 is supplied to the front chamber 435 via the first passage 401, pushing the injection device 300 forward. As the injection device 300 moves forward, the nozzle 320 is pressed against the fixed mold 810. The front chamber 435 functions as a pressure chamber that generates nozzle touch pressure on the nozzle 320 by the pressure of the hydraulic fluid supplied from the hydraulic pump 410.

[0092] Meanwhile, the rear chamber 436 of the hydraulic cylinder 430 is connected to the second port 412 of the hydraulic pump 410 via the second passage 402. The working fluid discharged from the second port 412 is supplied to the rear chamber 436 of the hydraulic cylinder 430 via the second passage 402, pushing the injection device 300 backward. As the injection device 300 is retracted, the nozzle 320 is separated from the fixed mold 810.

[0093] In this embodiment, the moving device 400 includes a hydraulic cylinder 430, but the present invention is not limited thereto. For example, instead of the hydraulic cylinder 430, an electric motor and a motion conversion mechanism that converts the rotational motion of the electric motor into the linear motion of the injection device 300 may be used.

[0094] (Control device) The control device 700 is, for example, a computer and, as shown in Figures 1 and 2, has a CPU (Central Processing Unit) 701, a storage medium 702 such as memory, an input interface 703, and an output interface 704. The control device 700 performs various controls by having the CPU 701 execute a program stored in the storage medium 702. The control device 700 also receives signals from the outside through the input interface 703 and transmits signals to the outside through the output interface 704.

[0095] The control device 700 repeatedly manufactures molded products by repeatedly performing processes such as metering, mold closing, pressure increasing, mold clamping, filling, holding pressure, cooling, depressurization, mold opening, and ejection. A series of operations to obtain a molded product, such as the operations from the start of one metering process to the start of the next metering process, is also called a "shot" or "molding cycle." The time required for one shot is also called the "molding cycle time" or "cycle time."

[0096] A single molding cycle includes, for example, a weighing process, a mold closing process, a pressurizing process, a clamping process, a filling process, a holding pressure process, a cooling process, a depressurizing process, a mold opening process, and an ejection process, in this order. The order here refers to the order in which each process begins. The filling, holding pressure, and cooling processes take place during the clamping process. The start of the clamping process may coincide with the start of the filling process. The completion of the depressurizing process coincides with the start of the mold opening process.

[0097] Furthermore, multiple processes may be performed simultaneously in order to shorten the molding cycle time. For example, the metering process may be performed during the cooling process of the previous molding cycle, or during the mold clamping process. In this case, the mold closing process may be performed at the beginning of the molding cycle. The filling process may also be started during the mold closing process. The ejection process may also be started during the mold opening process. If an on-off valve is provided to open and close the flow path of the nozzle 320, the mold opening process may be started during the metering process. This is because even if the mold opening process is started during the metering process, if the on-off valve closes the flow path of the nozzle 320, the molding material will not leak from the nozzle 320.

[0098] Furthermore, a single molding cycle may include steps other than the weighing step, mold closing step, pressurization step, mold clamping step, filling step, holding pressure step, cooling step, depressurization step, mold opening step, and ejection step.

[0099] For example, after the holding pressure process is completed and before the metering process begins, a pre-metering suck-back process may be performed in which the screw 330 is retracted to a preset metering start position. This reduces the pressure of the molding material accumulated in front of the screw 330 before the metering process begins and prevents the screw 330 from retracting too quickly at the start of the metering process.

[0100] Furthermore, after the metering process is completed and before the filling process begins, a post-metering suck-back process may be performed in which the screw 330 is retracted to a preset filling start position (also called the "injection start position"). This reduces the pressure of the molding material accumulated in front of the screw 330 before the filling process begins and prevents leakage of the molding material from the nozzle 320 before the filling process begins.

[0101] The control device 700 is connected to an operating device 750 that accepts user input operations and a display device 760 that displays a screen. The operating device 750 and the display device 760 may be integrated, for example, by a touch panel 770. The touch panel 770, as the display device 760, displays a screen under the control of the control device 700. The screen of the touch panel 770 may display information such as the settings of the injection molding machine 10 and the current status of the injection molding machine 10. The screen of the touch panel 770 may also display operation parts such as buttons and input fields that accept user input operations. The touch panel 770, as the operating device 750, detects user input operations on the screen and outputs a signal corresponding to the input operation to the control device 700. This allows, for example, the user to operate the operation parts provided on the screen while confirming the information displayed on the screen to set the injection molding machine 10 (including inputting setting values). Furthermore, by operating the operation parts provided on the screen, the user can make the injection molding machine 10 operate in accordance with the operation part. The operation of the injection molding machine 10 may also include the operation (including stopping) of, for example, the clamping device 100, the ejector device 200, the injection device 300, the moving device 400, etc. Furthermore, the operation of the injection molding machine 10 may also include switching the screens displayed on the touch panel 770, which serves as the display device 760.

[0102] Although the operating device 750 and display device 760 of this embodiment have been described as being integrated as a touch panel 770, they may be provided independently. Furthermore, multiple operating devices 750 may be provided. The operating device 750 and display device 760 are positioned on the operating side (negative Y-axis direction) of the clamping device 100 (more specifically, the fixed platen 110).

[0103] (Details of the control device) Next, an example of the components of the control device 700 will be described with reference to Figure 3. Note that the functional blocks shown in Figure 3 are conceptual and do not necessarily have to be physically configured as shown. All or part of each functional block can be functionally or physically distributed and integrated in any unit. Each processing function performed by each functional block can be implemented, in whole or in part, by a program executed on the CPU, or by hardware using wired logic.

[0104] As shown in Figure 3, the control device 700 includes, for example, a mold clamping control unit 711, an ejector control unit 712, an injection control unit 713, a metering control unit 714, and a display control unit 715. The mold clamping control unit 711 controls the mold clamping device 100 and performs the mold closing process, pressure boosting process, mold clamping process, depressurization process, and mold opening process shown in Figure 4. The ejector control unit 712 controls the ejector device 200 and performs the ejection process. The injection control unit 713 controls the injection drive source of the injection device 300 and performs the injection process. The injection drive source is, for example, an injection motor 350, but may also be a hydraulic cylinder or the like. The injection process includes a filling process and a holding pressure process. The injection process is performed during the mold clamping process. The metering control unit 714 controls the metering drive source of the injection device 300 and performs the metering process. The metering drive source is, for example, a metering motor 340, but may also be a hydraulic pump or the like. The weighing process is performed during the cooling process. The display control unit 715 controls the display device 760.

[0105] The filling process involves controlling the injection drive source so that the actual value of the movement speed of the injection member located inside the cylinder 310 reaches a set value. The filling process involves moving the injection member forward to fill the inside of the mold device 800 with liquid molding material (e.g., resin) accumulated in front of the injection member. The injection member is, for example, a screw 330, but it may also be a plunger.

[0106] The movement speed of the injection member is detected using a speed detector. The speed detector is, for example, an injection motor encoder 351. In the filling process, as the injection member moves forward, the pressure acting on the molding material from the injection member increases. The filling process may include a step of temporarily stopping the injection member or a step of retracting the injection member immediately before the holding pressure process.

[0107] The holding pressure process is a process of controlling the injection drive source so that the actual pressure acting on the molding material from the injection member reaches a set value. The holding pressure process is a process of replenishing the molding material that has been lost due to cooling shrinkage within the mold device 800 by pushing the injection member forward. The pressure is detected using a pressure detector such as a load detector 360. A nozzle pressure sensor or an in-mold pressure sensor may be used as the pressure detector.

[0108] The holding pressure process is controlled by the injection control unit 713. As shown in Figure 5, the injection control unit 713 includes, for example, a speed command generation unit 713a and a voltage command generation unit 713b. The speed command generation unit 713a generates a speed command value Vref for the screw 330 based on the pressure set value Pref and the actual pressure value Pdet. The voltage command generation unit 713b generates a voltage command value for the inverter 600 based on the speed command value Vref and the actual speed value Vdet. The inverter 600 supplies alternating current to the injection motor 350 according to the voltage command value.

[0109] The speed command generation unit 713a creates a speed command value Vref such that the actual pressure value Pdet becomes the pressure setpoint Pref. For example, the speed command generation unit 713a creates the speed command value Vref such that the absolute value of the difference Pdev (Pdev = Pref - Pdet) between the actual pressure value Pdet and the pressure setpoint Pref becomes small (preferably zero). The actual pressure value Pdet is obtained using a pressure detector such as the load detector 360. For example, PI calculation or PID calculation may be used to create the speed command value Vref.

[0110] The voltage command generation unit 713b generates a command for the injection drive source so that the actual speed value Vdet becomes the speed command value Vref. For example, the voltage command generation unit 713b generates a voltage command value such that the absolute value of the difference Vdev (Vdev = Vref - Vdet) between the speed command value Vref and the actual speed value Vdet becomes small (preferably zero). The actual speed value Vdet is obtained using a speed detector such as the injection motor encoder 351. PID calculation or PI calculation, for example, can be used to generate the voltage command value.

[0111] The injection control unit 713 includes a speed command correction unit 713c. During the injection process, the speed command correction unit 713c selectively performs either retraction speed control or retraction speed limiting while the screw 330 is retracting. The choice between retraction speed control and retraction speed limiting is set using a screen 761 (see Figure 8), which will be described later.

[0112] Furthermore, the speed command correction unit 713c can choose not to perform either reverse speed control or reverse speed limiting. In that case, the speed command correction unit 713c inputs the speed command value Vref created by the speed command creation unit 713a directly to the voltage command creation unit as the second speed command value Vrefa (see Figure 6).

[0113] Reverse speed control controls the actual speed value Vdet of the screw 330 to a first set value V1 (>0) while the screw 330 is retracting. Reverse speed control is a form of feedback control. Reverse speed control is implemented when the forward speed of the injection member is set to a high speed in the filling process, for example, when the thickness of the molded product is thin. By implementing reverse speed control, the resin pressure can be released, and the uneven distribution of residual stress can be suppressed. Therefore, warping of the molded product can be suppressed.

[0114] When the speed command correction unit 713c performs reverse speed control, it inputs the first set value V1 as the second speed command value Vrefa to the voltage command creation unit 713b, regardless of the speed command value Vref created by the speed command creation unit 713a. As a result, the actual speed value Vdet becomes the first set value V1 while the screw 330 is reversing.

[0115] On the other hand, the retraction speed limit restricts the actual speed value Vdet of the screw 330 to a second set value V2 (>0) or less while the screw 330 is retracting. This eliminates the adverse effect on the quality of the molded product caused by the screw 330 retracting at high speed immediately after V / P switching. The second set value V2 is set to eliminate the adverse effect on the quality of the molded product caused by the screw 330 retracting at high speed.

[0116] When the speed command correction unit 713c implements a reverse speed limit, it compares the speed command value Vref (Vref>0) with the second setting value V2 (V2>0) and inputs the minimum value as the second speed command value Vrefa to the voltage command creation unit 713b. Note that if Vref and V2 are equal, Vrefa is equal to Vref.

[0117] The voltage command generation unit 713b generates a second voltage command value based on the second speed command value Vrefa and the actual speed value Vdet generated by the speed command correction unit 713c. The voltage command generation unit 713b generates the second voltage command value such that the absolute value of the difference Vdeva (Vdeva = Vrefa - Vdet) between the second speed command value Vrefa and the actual speed value Vdet becomes small (preferably zero). The inverter 600 supplies alternating current to the injection motor 350 according to the second voltage command value. This allows for selective implementation of either reverse speed control or reverse speed limiting.

[0118] Furthermore, the injection control unit 713 may temporarily stop the screw 330 immediately before selectively performing either reversal speed control or reversal speed limiting.

[0119] Next, with reference to Figure 7, an example of a screen 761 used for selecting between reverse speed control and reverse speed limiting will be described. Screen 761 has, for example, a selection unit 762 that accepts a selection of whether to implement reverse speed control or reverse speed limiting. The selection unit 762 may also accept a selection of not to implement either reverse speed control or reverse speed limiting.

[0120] The selection unit 762 displays multiple options in response to user input. These options are displayed, for example, in a pull-down menu. Examples of these options include "Control," "Restrict," and "Off." The selection unit 762 then displays the option (setting) selected by the user from among the multiple options.

[0121] When the display on the selection unit 762 is "Control," the speed command correction unit 713c performs reverse speed control. On the other hand, when the display on the selection unit 762 is "Restrict," the speed command correction unit 713c performs reverse speed restriction. When the display on the selection unit 762 is "Off," the speed command correction unit 713c does not perform either reverse speed control or reverse speed restriction.

[0122] Note that, as multiple options, only "control" and "limit" may be used, and "off" may not be used. In this case, if no numerical value is entered in either the first input field or the second input field (as described later) (in this embodiment, if no numerical value is entered in the shared input field 763), the speed command correction unit 713c will not perform either reverse speed control or reverse speed limiting.

[0123] According to this embodiment, by displaying a screen 761 having a selection section 762, the settings for the injection process can be switched according to the molded product. The injection control unit 713 controls the injection motor 350 according to the settings using the screen 761. Reverse speed control and reverse speed limiting can be selectively implemented depending on the molded product.

[0124] Screen 761 has a combined input field 763 that serves as both a first input field for entering a first setting value V1 and a second input field for entering a second setting value V2. By combining the first and second input fields into a single combined input field 763, the screen display can be simplified compared to the case where the first and second input fields are provided separately.

[0125] The user looks at screen 761 and enters a number into the shared input field 763 using the numeric keypad or similar. The shared input field 763 displays the number entered by the user.

[0126] The selection section 762 and the shared input field 763 are arranged side by side. The selection section 762 and the shared input field 763 are adjacent to each other horizontally or vertically (horizontally in Figure 7). By arranging the selection section 762 and the shared input field 763 side by side, it is easy to determine whether the numerical value entered in the shared input field 763 is the first setting value V1 or the second setting value V2.

[0127] If the display on the selection unit 762 is "Control", the speed command correction unit 713c uses the numerical value entered in the shared input field 763 as the first setting value V1. On the other hand, if the display on the selection unit 762 is "Restriction", the speed command correction unit 713c uses the numerical value entered in the shared input field 763 as the second setting value V2.

[0128] Screen 761 has a retraction amount input field 764 for inputting a set value L1 for the retraction amount of the screw 330 as a condition for releasing the retraction speed control. When the retraction amount of the screw 330 reaches the set value L1, the retraction speed control is released. After that, pressure control is performed. It is possible to transition from retraction speed control to pressure control and apply a constant pressure to the molding material until the end of the injection process.

[0129] The user, while looking at screen 761, enters a numerical value into the retraction amount input field 764 using the numeric keypad or similar. The retraction amount input field 764 displays the numerical value entered by the user.

[0130] The first input field (a shared input field 763 in this embodiment) and the reversal amount input field 764 are arranged side by side. The reversal amount input field 764 and the first input field are adjacent to each other horizontally or vertically (vertically in Figure 7). By arranging the reversal amount input field 764 and the first input field side by side, it is easier to calculate the time required to perform reversal speed control. The time required to perform reversal speed control is approximately equal to L1 / V1.

[0131] Screen 761 may have input fields 765A, 765B, 766A, and 766B for inputting the setting values ​​for the holding pressure process. When the holding pressure process is divided into n (where n is an integer greater than or equal to 2) processes, the k (where k is an integer greater than or equal to 1 than or equal to n) process from the one closest to the filling process is called the k-th stage process. Although the number of divisions is 2 in Figure 7, there may be 3 or more.

[0132] Input fields 765A and 766B are for entering the setting values ​​T1 and Pref1 for the first stage of the process. T1 is the time to execute the first stage of the process, and Pref1 is the pressure setting value for the first stage of the process. Input fields 765B and 766B are for entering the setting values ​​T2 and Pref2 for the second stage of the process. T2 is the time to execute the second stage of the process, and Pref2 is the pressure setting value for the second stage of the process.

[0133] Reverse speed control is performed in place of the first stage of the holding pressure process. Therefore, it is preferable that screen 761 has the first input field (e.g., the shared input field 763) and input fields 765A, 765B, 766A, and 766B arranged side by side. This makes it clear that reverse speed control is performed in place of the first stage of the holding pressure process.

[0134] It is more preferable that the input fields 765A and 766A for inputting the setting values ​​for the first stage of the process, the first input field (a shared input field 763 in this embodiment), and the retraction amount input field 764 are arranged in a single row. These input fields are arranged, for example, vertically.

[0135] As will be explained in more detail later, input field 765A serves as both an input field for inputting the setting value T1 for the time to perform the first stage of the pressure holding process, and an input field for inputting the setting value T1 for the time to perform reverse speed control.

[0136] Next, with reference to Figure 8, an example of the time variation of screw speed, pressure, and screw position when retraction speed control is selected will be described. An example of the time variation of screw speed, pressure, and screw position when retraction speed limiting is selected is shown in Patent Document 1, so the illustration will be omitted.

[0137] In Figure 8, the screw position is represented by the distance from the forward limit position. The further the screw position is retracted from the forward limit position, the larger the distance representing the screw position. The forward limit position is determined, for example, by the stroke of the ball screw that converts the rotational motion of the injection motor 350 into the linear motion of the screw 330.

[0138] In Figure 8, t0 represents the start time of the injection process, t1 represents the start time of the retraction speed control, t2 represents the time when the retraction amount of the screw 330 reaches the set value L1, t3 represents the time when the elapsed time from the start of the retraction speed control reaches the set value T1, and t4 represents the end time of the injection process. Note that t1 corresponds to the time of V / P switching.

[0139] When the filling process starts at time t0, the screw position advances at the set speed. As a result, the pressure increases. Then, at time t1, when the screw position reaches the retraction speed control start position, retraction speed control is initiated. Retraction speed control controls the injection motor 350 so that the actual speed value Vdet becomes the first set value V1. Retraction speed control allows the actual pressure value Pdet to decrease rapidly.

[0140] Reverse speed control is performed until time t2 when the retraction amount of screw 330 reaches the set value L1. From time t2 to time t3, screw 330 is temporarily stopped and the actual speed value Vdet becomes zero. From time t3, the second stage of the holding pressure process is performed and the actual pressure value Pdet becomes the pressure set value Pref2.

[0141] In this embodiment, the amount of retraction of the screw 330 reaches the set value L1 before time t3, but the amount of retraction of the screw 330 does not have to reach the set value L1 at time t3. In this case, the retraction speed control is released at time t3, and the second stage of the holding pressure process is performed.

[0142] In other words, even if the amount of retraction from time t1 has not reached the set value L1, if the elapsed time from time t1 has reached the set value T1, the retraction speed control is released and the second stage of the holding pressure process is performed.

[0143] The embodiments of the control device for an injection molding machine, the injection molding machine, and the control method for an injection molding machine according to the present invention have been described above, but the present invention is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope described in the claims. These also naturally fall within the technical scope of the present invention. [Explanation of Symbols]

[0144] 10 injection molding machine 310 Cylinder 330 Screw (Injection Molding Part) 350 Injection motor (injection drive source) 700 Control Unit 760 Display device 761 screens 762 Selection Section 800 mold equipment

Claims

1. A display device for an injection molding machine comprising an injection member provided inside a cylinder for heating a molding material, and an injection drive source that advances the injection member to fill the molding material inside a mold device, In an injection process that controls the speed of the injection member or the pressure applied by the injection member to the molding material, a screen is displayed that accepts a selection of whether to perform retraction speed control, which controls the actual speed of the injection member to a first set value, or retraction speed limiting, which limits the actual speed of the injection member to a second set value or less, while the injection member is retracting. Display device for injection molding machines.

2. The display device for an injection molding machine according to claim 1, wherein the screen has a combined input field that serves as both a first input field for inputting the first setting value and a second input field for inputting the second setting value.

3. The display device for an injection molding machine according to claim 2, wherein the selection unit and the combined input field are arranged side by side.

4. The display device for an injection molding machine according to any one of claims 1 to 3, wherein the screen has a retraction amount input field for inputting a set value for the retraction amount of the injection member as a condition for releasing the retraction speed control.

5. The injection process includes a holding pressure step that controls the pressure acting on the molding material from the injection member, The display device for an injection molding machine according to any one of claims 1 to 3, wherein the screen has a first input field for inputting the first setting value and an input field for inputting the setting value for the holding pressure process arranged side by side.

6. The injection process comprises, in this order, a filling process for controlling the speed of the injection member and a holding pressure process. If the holding pressure process is divided into n steps (where n is an integer of 2 or more), and the k-th step (where k is an integer of 1 or more and n or less) from the step closest to the filling process is designated as the k-th step, The display device for an injection molding machine according to claim 5, wherein the screen has an input field that serves as both an input field for inputting a set value for the time to perform the first stage of the holding pressure process and an input field for inputting a set value for the time to perform the retraction speed control.

7. A control device for an injection molding machine, which controls the injection process according to settings using a display device according to any one of claims 1 to 3.

8. An injection molding machine comprising a display device according to any one of claims 1 to 3, the injection member, and the injection drive source.

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