Control device of injection molding machine, injection molding machine, and injection molding system

Abstract

To provide a controller of an injection molding machine which can stably move a movable mold of a mold device by mold clamping compression, and to provide the injection molding machine and an injection molding system.SOLUTION: A control device of the present invention is a control device of an injection molding machine 1 to which a mold unit 101 is attached, in which the mold unit 101 includes a movable mold 103 and a fixed mold 102, and the injection molding machine 1 is capable of performing mold clamping compression in which the movable mold 103 of the mold unit 101 moves from a mold opening position toward an injection start position, a molding material Mm is injected into an internal space Si of the mold unit 101, and the movable mold 103 further moves from the injection start position to a mold clamping completion position to compress the molding material Mm, the control device controls the movement of the movable mold 103 such that the moving speed of the movable mold 103 is reduced during the movement of the movable mold 103 from the mold open position to the injection start position.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a control device for an injection molding machine to which a mold device is attached, an injection molding machine, and an injection molding system. [Background technology]

[0002] Techniques relating to this type of injection molding machine are described in Patent Documents 1 and 2, for example.

[0003] Patent Document 1 describes a mold clamping control device used in an injection molding machine that is equipped with a mold clamping motor that drives a movable platen via a torque-type mold clamping mechanism, and that performs mold clamping using the movable platen and fixed platen to inject molten resin into a mold to form a molded product, and that has a first sensor that detects the relative position of the movable platen and the fixed platen, a second sensor that detects the mold clamping force, a target value generator that generates a platen position target value and a mold clamping force target value, and control means that controls the mold clamping motor, and the control means has a subtractor that subtracts the platen position and the mold clamping force from the platen position target value and the mold clamping force target value to obtain a deviation, a changeover switch that switches the control target to platen position or mold clamping force, and a compensator that converts the deviation of the platen position and the mold clamping force obtained by the subtractor into a control command value for the motor.

[0004] Patent Document 2 describes a method for controlling mold clamping of an injection molding machine, characterized in that, in an injection molding machine having a mold clamping mechanism that drives a lower platen, a mold clamping force detection device, and a mold clamping position detection device, the upper platen equipped with an upper mold is fixed and the lower platen equipped with a lower mold is made movable, and when performing mold clamping control, the method controls the movement of the lower platen by combining mold clamping force control that performs feedback control based on the mold clamping force detected by the mold clamping force detection device and mold clamping position control that controls based on the mold clamping position detected by the mold clamping position detection device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-185344 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-341180 Summary of the Invention [Problem to be solved by the invention]

[0006] When performing mold clamping compression with an injection molding machine, it is possible to measure the distance between molds or the distance between platens in the mold device, and perform feedback control so that the movable mold moves from the mold open position to the injection start position based on the measured value.

[0007] Even if such feedback control has good responsiveness, it is undeniable that it takes time from the acquisition of the measurement value to the execution of the movement control of the movable mold. Therefore, if relying on such feedback control, the movement of the movable mold to the injection start position may not be stable, which may cause the injection operation to become unstable.

[0008] The present invention aims to solve such problems, and its purpose is to provide an injection molding machine control device, an injection molding machine, and an injection molding system that can stably move the movable mold of a mold device by mold clamping compression. [Means for solving the problem]

[0009] One control device that can solve the above-mentioned problem is a control device for an injection molding machine to which a mold device is attached, wherein the mold device has a movable mold and a fixed mold, and in the injection molding machine, the movable mold of the mold device moves from a mold opening position toward an injection start position to inject molding material into the internal space of the mold device, and the movable mold moves further from the injection start position to a mold clamping completion position to perform mold clamping compression to compress the molding material, and the control device controls the movement of the movable mold so that the moving speed of the movable mold slows down during its movement from the mold opening position to the injection start position.

[0010] The injection molding machine is equipped with the above-described control device.

[0011] The injection molding system includes the above-described injection molding machine and a mold device attached to the injection molding machine. [Effects of the Invention]

[0012] According to the above control device, the movable mold of the mold device can be moved stably by mold clamping compression. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view showing an injection molding machine in which a control device according to an embodiment of the present invention can be used, together with a mold device attached to the injection molding machine. [Figure 2] 1 is a block diagram showing a control device according to an embodiment of the present invention; [Figure 3] 2 is an enlarged cross-sectional view of a mold device and a main part of the injection molding machine, showing an example of an injection molding operation using the injection molding machine of FIG. 1. FIG. [Figure 4] 4 is a cross-sectional view showing the operation following FIG. 3. [Figure 5] 5 is a cross-sectional view showing the operation following FIG. 4. [Figure 6] FIG. 6 is a cross-sectional view showing the operation following FIG. 5. [Figure 7] 7 is a cross-sectional view showing the operation following FIG. 6. [Figure 8] 10 is a graph showing an example of a change in the position of a movable mold over time in feedback control of a reference example. [Figure 9] 10 is a graph showing an example of a change over time in the position of a movable mold under control by a control device according to an embodiment of the present invention. [Figure 10] FIG. 10(a) is a graph showing an enlarged view of a main part of FIG. 9, and FIG. 10(b) is a similar graph showing another example of control. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. A control device according to one embodiment of the present invention can be used in, for example, an injection molding machine 1 as shown in Fig. 1. The injection molding machine 1 in Fig. 1 generally includes an injection device 11 that melts a molding material Mm, such as a thermoplastic resin, and injects it into a mold device 101 by rotating and advancing a screw 13 disposed inside and heating it with a heater 14 disposed around the device, a movement device 21 that moves the injection device 11 forward and backward relative to the mold device 101, a mold clamping device 31 that moves the mold device 101 between a mold open state and a mold clamping state to open and close it, and an ejector device 41 that removes a molded product from the mold device 101 in the mold open state.

[0015] In the illustrated example, the mold assembly 101 attached to the injection molding machine 1 is attached to the fixed platen 32a and movable platen 32b of the mold clamping device 31, respectively, and includes a fixed mold 102 and a movable mold 103 that define an internal space Si including a cavity therein when the mold assembly 101 is in a clamped state, and a movable member 104 such as an ejector pin that is displaced by the ejector device 41 to push out and remove a molded product. The mold assembly 101 can be attached to or replaced with another mold as appropriate depending on the shape of the molded product to be manufactured, and is not considered to be part of the injection molding machine 1. Here, an arrangement including the injection molding machine 1 and the mold assembly 101 attached to the injection molding machine 1 is referred to as an injection molding system.

[0016] (Control device) The control device may be any device that can control the movement of the movable mold 103 of the mold device 101 by the mold clamping device 31. The control device may be dedicated to the mold clamping device 31, but in many cases, it can also control the operation of not only the mold clamping device 31 but also the injection device 11, the moving device 21, the mold clamping device 31, and other devices of the injection molding machine 1.

[0017] As an example, the control device has a calculation unit, as shown in FIG. 2. The calculation unit may be composed of a processor, a RAM (Random Access Memory), a ROM (Read Only Memory), etc. The control device may further have an input unit used by the user of the injection molding machine 1 to input information, a display unit used to convey information to the user, and / or a memory unit for storing information or data. In a control device having an input unit and a display unit, at least a part of them may be a touch panel. The memory unit may include an HDD (Hard Disk Drive), a flash memory, etc.

[0018] The calculation unit can be configured to be able to transmit and receive data or signals to and from the display unit, input unit, memory unit, various drive sources, various sensors, etc. via a bus. Examples of the various drive sources and sensors include the clamping motor 35 of the clamping device 31 of the injection molding machine 1, as well as a metering motor, an injection motor, and other various drive sources, sensors for measuring temperature and rotation speed, etc.

[0019] The control device can perform the control described below by executing a control program recorded in the ROM or storage unit by the processor. The injection molding machine 1 may be equipped with such a control device.

[0020] (Molding equipment) The illustrated mold device 101 is configured so that the mold clamping device 31 can clamp and compress the molding material Mm between a fixed mold 102 and a movable mold 103 .

[0021] More specifically, in this mold device 101, as shown in Figure 3, the movable mold 103 is provided with, in order from the movable platen 32b side to the fixed mold 102 side, a movable side mounting plate 106 attached to the movable platen 32b, a spacer block 107 that defines a space Se in which the protruding plate 105a is disposed, a receiving plate 108 provided with an elastic member 108a, and a movable side mold plate 109 that faces the fixed mold 102.

[0022] The movable mold plate 109 of the movable mold 103 is fixedly attached to the surface of the backing plate 108 facing the fixed mold 102, and is divided into multiple members including a material pressing member 109a that presses the molding material Mm by clamping compression, and a pressure member 109b that is supported by the backing plate 108 via an elastic member 108a and is pressed against the fixed mold 102 when a clamping force is applied. As shown in Fig. 3, two block-shaped or similar material pressing members 109a and three pressure members 109b are alternately arranged in a direction (vertical direction in Fig. 3) perpendicular to the direction in which the movable platen 32b approaches the fixed platen 32a (horizontal direction in Fig. 3, also referred to as the "movable platen moving direction").

[0023] Each of the receiving plate 108 and the three material pressing members 109a and pressure members 109b located on the inside in a direction perpendicular to the direction of movement of the movable platen has a through hole formed therein extending from the space Se to the internal space Si. A plurality of movable members 104 are inserted and positioned inside each of these through holes, and these movable members 104 are connected to a protruding plate 105a located within the space Se.

[0024] The elastic member 108a provided on the receiving plate 108 can be a spring member such as a coil spring that resists the clamping force acting in the direction of movement of the movable platen, or it can be a cylinder that moves the pressure member 109b in the same direction, although not shown in the figure.

[0025] The illustrated fixed mold 102 includes a fixed-side mounting plate 110 attached to the fixed platen 32a, and a fixed-side mold plate 111 provided on the surface of the fixed-side mounting plate 110 facing the movable mold 103. A sprue bushing 112 is provided in the approximate center region of the fixed-side mounting plate 110 and the fixed-side mold plate 111. A sprue 112a is formed inside the sprue bushing 112 to guide the molding material Mm injected from the injection unit 11 into the internal space Si.

[0026] (mold clamping compression) When the above-described mold device 101 is attached to the injection molding machine 1, the control device can execute clamping compression of the molding material Mm, for example, as described below.

[0027] First, the mold clamping device 31 is used to move the movable mold 103, which is at the mold open position in the mold assembly 101 in the mold open state shown in Fig. 3, toward the injection start position on the fixed mold 102 side, as shown in Fig. 4. Here, such movement of the movable mold 103 slightly compresses the elastic member 108a, as shown in Fig. 5, and the restoring force of the elastic member 108a presses the pressure member 109b against the fixed mold plate 111 with a predetermined clamping force. This prevents flash from occurring in the molded product formed after the molding material Mm is filled into the cavity between the pressure member 109b and the fixed mold plate 111, as described below. When the movable mold 103 reaches the injection start position, a cavity is defined in the internal space Si of the mold assembly 101.

[0028] Then, the molding material Mm accumulated at the tip of the cylinder 12 of the injection unit 11 is injected from the nozzle 12b toward the internal space Si of the mold apparatus 101. As shown in FIG. 6, the molding material Mm injected from the injection unit 11 passes through the sprue 112a inside the sprue bushing 112, reaches the internal space Si of the mold apparatus 101, and fills the internal space Si. In this example, among the pressure members 109b supported by the elastic member 108a of the movable-side mold plate 109 of the movable mold 103, the central pressure member 109b facing the sprue 112a is formed so that its opposing surface is recessed toward the movable platen 32b from the parting line, which is the boundary between the other pressure members 109b and the fixed-side mold plate 111. In the internal space Si, the void between the central pressure member 109b and the fixed-side mold plate 111 functions as a runner. Between the central pressure member 109b and each of the adjacent material pressing members 109a on both sides thereof, gates 109c are formed to allow the molding material Mm to flow into the cavity of the internal space Si on the material pressing member 109a side (see FIG. 5).

[0029] To perform clamping compression, during or after the injection of the molding material Mm into the internal space Si of the mold device 101, the mold clamping device 31 moves the movable mold 103 from the injection start position to the clamping completion position on the fixed mold 102 side, as shown in Fig. 7. This further compresses the elastic member 108a, and the molding material Mm in the internal space Si is compressed between the fixed mold 102 and the movable mold 103. When clamping compression is performed, the molding material Mm is sufficiently distributed and filled throughout the entire cavity of the internal space Si, even when a relatively thin molded product is being molded, so that molding defects such as sink marks can be effectively prevented.

[0030] In the above-described mold clamping compression, for example, if the distance between the movable mold 103 and the fixed mold 102 is measured and feedback control is performed based on the measurement value so that the movable mold 103 moves from the mold opening position to the injection start position, the movement of the movable mold 103 may not be stable.

[0031] More specifically, as in the feedback control of the reference example shown in FIG. 8 , when the movable mold 103 moves from the mold open position and approaches the injection start position, there may be a slight time lag between the acquisition of the measured value of the mold-to-mold distance and the actual stopping of the movable mold 103 at the injection start position, causing the movable mold 103 to unintentionally pass the injection start position without stopping at the injection start position. In this case, based on the information on the measured value of the mold-to-mold distance, it is detected that the movable mold 103 has passed the injection start position, and the movable mold 103 may be controlled to retreat in the direction opposite to the fixed mold 102. Furthermore, if the movable mold 103 retreats too far past the injection start position, it may be controlled to advance again toward the fixed mold 102. If feedback control alone is relied upon, the movable mold 103 will repeatedly advance and retreat before and after the injection start position, resulting in unstable movement of the movable mold 103 and, accordingly, unstable injection operation. In addition, in this reference example, the molding material Mm is not injected from the injection device 11 into the internal space Si of the mold device 101 until the movable mold 103 has completely stopped at the injection start position, which results in a longer cycle time.

[0032] In contrast, in this embodiment, the control device controls the movement of the movable mold 103 so that the moving speed of the movable mold 103 slows down while the movable mold 103 is moving from the mold open position to the injection start position. Here, it is known in advance that if the moving speed of the movable mold 103 is fast as it approaches the injection start position, its movement will become unstable. Therefore, this can be predicted and feedforward control can be performed to slow down the moving speed of the movable mold 103 while it is moving from the mold open position to the injection start position. By slowing down the moving speed of the movable mold 103 in this way, it is possible to prevent the movement of the movable mold 103 from becoming unstable near the injection start position. This type of control may be combined with the feedback control of the above-mentioned reference example, but even in this case, it is possible to set the moving speed of the movable mold 103 to slow down while it is moving from the mold open position to the injection start position, independently of the feedback control.

[0033] The deceleration mode of the moving speed of the movable mold 103 can be determined appropriately depending on various conditions. Preferably, as exemplified in Fig. 9, the control device accelerates the movable mold 103 when it starts to move from the mold open position to the injection start position, and ends the acceleration and switches to deceleration when the movable mold 103 approaches the injection start position to a certain extent. In this case, the change over time in the position of the movable mold 103 from the mold open position to the injection start position switches from an upward convex curve on the mold open position side to a downward convex curve or a straight line on the injection start position side, as shown in the graph in Fig. 9.

[0034] Furthermore, when the control device decelerates the moving speed of the movable mold 103 during movement from the mold open position to the injection start position, it is preferable to gradually decrease the moving speed so that the moving speed of the movable mold 103 gradually decreases as the movable mold 103 approaches the injection start position. When controlled in this manner, the change in the position of the movable mold 103 over time becomes a smooth, downwardly convex curve with a gradually decreasing slope as the movable mold 103 approaches the injection start position, as shown in FIG. 10( a). However, the moving speed may be constant for at least part of the deceleration period of the movable mold 103. The moving speed of the movable mold 103 may also be decreased in one or more stages. In another example shown in FIG. 10( b), the moving speed is rapidly decreased in stages at three deceleration points and maintained constant between them. As a result, the change in the position of the movable mold 103 over time on the graph is composed of multiple straight lines with different slopes.

[0035] The control device may slow down the moving speed of the movable mold 103 while it is moving from the mold open position to the injection start position, and when the movable mold 103 reaches the injection start position, stop the movable mold 103 at the injection start position. Alternatively, the control device may allow the movable mold 103 to pass through the injection start position without stopping it. Furthermore, the control device preferably continuously moves the movable mold 103 toward the fixed mold 102 without stopping it, as shown in FIG. 9 , while the molding material Mm is being injected into the internal space Si of the mold device 101. If the movable mold 103 is stopped at the injection start position and injection of the molding material Mm is started after stopping, time is required for braking to stop the movable mold 103 and for the movable mold 103 to resume moving after injection starts. In particular, when the movable mold 103 resumes moving, significant drive resistance is generated by static friction between the various parts or components of the injection molding machine 1, and restarting the movement requires a certain amount of time. In contrast, starting injection of the molding material Mm without stopping the movable mold 103 can shorten the cycle time.

[0036] When the control device does not stop the movable mold 103 at the injection start position, it is preferable that the control device controls the moving speed of the movable mold 103 to be sufficiently slowed down when it reaches the injection start position, so that the movable mold 103 passes through the injection start position at a very slow speed. The moving speed of the movable mold 103 when passing through at this very slow speed may be, for example, 10% or less of the maximum speed from the mold open position to the injection start position, but is not limited to this.

[0037] However, if the movable mold 103 is not stopped at the injection start position, in order to fully obtain the effect of improving the filling of the molding material Mm into the cavity of the internal space Si of the mold device 101 by mold clamping compression, it is desirable that a certain amount of opening of the mold device 101 is ensured when compression of the molding material Mm begins.

[0038] In this regard, as an example, assume that the molding material Mm is set to be injected into the internal space Si of the mold device 101 when the opening amount of the mold device 101 is 0.3 mm. In this case, if the movement of the movable mold 103 is controlled so that compression of the molding material Mm begins when the opening amount of the mold device 101 becomes approximately 0.2 mm due to the movement of the movable mold 103, the molding material Mm can be sufficiently compressed by mold clamping compression.

[0039] As another example, assume that the movable mold 103 moves at a speed of 1 mm / sec, injection of the molding material Mm begins when the mold assembly 101 has an opening amount of 2 mm, and compression of the molding material Mm begins 0.05 seconds later. In this case, the movable mold 103 moves 0.05 mm in the aforementioned 0.05 seconds, so the opening amount of the mold assembly 101 at the start of compression is 1.95 mm, and this opening amount is sufficient to compress the molding material Mm effectively. Here, even if the moving speed of the movable mold 103 were 10 mm / sec instead of the aforementioned 1 mm / sec, the movement amount of the movable mold 103 from the start of injection of the molding material Mm to the start of compression would be 0.5 mm, and the opening amount of the mold assembly 101 at the start of compression would be 1.5 mm. Therefore, it is estimated that with this opening amount, the molding material Mm can be compressed without any problems.

[0040] Based on the assumptions described above, it is considered preferable that the control device control the movement of the movable mold 103 so that the opening amount of the mold device 101 at the start of compression of the molding material Mm is 1 / 3 to 1 / 2 times the opening amount of the mold device 101 at the start of injection of the molding material Mm. Ensuring this degree of opening amount of the mold device 101 at the start of compression allows the full effect of mold clamping compression to be obtained. Furthermore, by not making the opening amount of the mold device 101 at the start of compression too large compared to the opening amount of the mold device 101 at the start of injection, the cycle time can be effectively reduced.

[0041] Here, "the start of injection of the molding material Mm" refers to the time when the molding material Mm injected from the injection unit 11 begins to enter the internal space Si of the mold assembly 101. Furthermore, "the start of compression of the molding material Mm" refers to the time when the movable mold 103 resumes movement if the movable mold 103 is stopped at the injection start position, or the time when the movable mold 103 begins to accelerate after reaching the injection start position if the movable mold 103 is not stopped at the injection start position. In the example shown in FIG. 9 , the transition point from the straight line obtained when the movable mold 103 passes the injection start position at a slow and constant speed to an upwardly convex curve corresponds to the start of compression of the molding material Mm. The "opening amount of the mold assembly 101" refers to the mold-to-mold distance between the movable mold 103 and the fixed mold 102 of the mold assembly 101 along the direction of movement of the movable platen. It is sufficient if at least a portion of the mold-to-mold distance in the mold assembly 101 is within the above-mentioned range.

[0042] After the movable mold 103 passes the injection start position, injection of the molding material Mm into the internal space Si of the mold device 101 begins, and during or after the injection is completed, the control device can accelerate the moving speed of the movable mold 103 to move the movable mold 103 to the mold clamping completion position, as shown in Fig. 9. This causes mold clamping compression to be performed.

[0043] (mold clamping device) The mold clamping device 31 moves the movable mold 103 toward or away from a fixed mold 102 of the mold device 101, thereby opening and closing the mold device 101. As shown in Fig. 1, the mold clamping device 31 has platens 32 including a fixed platen 32a and a movable platen 32b, and a platen operating mechanism 33 that operates the platen 32.

[0044] Of the platens 32, the fixed platen 32a is fixedly attached to the base frame 2. On the other hand, the movable platen 32b is disposed on a guide member 32d laid on the base frame 2 and can slide in a direction away from and toward the fixed platen 32a. The mold clamping unit 31 is provided with one or more tie bars 32c that extend from the fixed platen 32a toward a rear platen 34 (described later) and connect the fixed platen 32a and the rear platen 34. In this example, the movable platen 32b is guided by the tie bars 32c in its movement toward and away from the fixed platen 32a, but it is not necessarily required that the movable platen 32b be guided by the tie bars 32c.

[0045] The platen operating mechanism 33 includes a rear platen 34 arranged on the base frame 2, a mold clamping motor 35 provided on the rear platen 34, a motion conversion mechanism 36 that converts the rotational motion of the mold clamping motor 35 into linear motion in the direction of movement of the movable platen, and a toggle mechanism 37 that amplifies the force transmitted to the motion conversion mechanism 36 and transmits it to the movable platen 32b.

[0046] Of these, the motion conversion mechanism 36 can be various mechanisms that can convert the rotational motion of the mold clamping motor 35 into linear motion, but in this example, it is configured to include a screw shaft 36a that is rotationally driven by the mold clamping motor 35 and a nut 36b that is screwed onto the screw shaft 36a. The motion conversion mechanism 36 can also be a ball screw.

[0047] The toggle mechanism 37 that increases the force transmitted from the motion conversion mechanism 36 is formed by connecting a plurality of links 37a to 37c that connect the rear platen 34 and the nut 36b to the movable platen 32b with joints so that they can swing. The number and shape of the links and joints can be changed as appropriate, but as shown in Figure 1, a pair of link groups consisting of links 37a to 37c located above and below crosshead 37d, separated by crosshead 37d, are swingably connected to crosshead 37d, which is connected to nut 36b and extends in the vertical direction.

[0048] In addition to the above-mentioned mold clamping motor 35, a mold thickness adjustment motor 38 can also be provided on the rear platen 34. This mold thickness adjustment motor 38 functions to adjust the distance between the fixed platen 32a and the rear platen 34, which is movably mounted on the base frame 2, by applying a rotational driving force to a screw shaft and a nut connected to an extension portion of each tie bar 32c of the platen 32. This makes it possible to adjust the mold thickness so that a desired mold clamping force can be applied to the mold device 101, even when replacing the mold device 101 or when the thickness of the mold device 101 is changed due to temperature changes. Although not shown in the drawings, mold thickness adjustment can also be achieved even if the fixed platen side is made movable on the base frame 2 and the rear platen side is fixed.

[0049] The illustrated mold clamping unit 31 is a horizontal type in which the moving direction of the movable platen 32b is parallel to the horizontal direction, but it may also be a vertical type in which the moving direction is vertical.

[0050] (injection device) 1, the injection unit 11 mainly includes a cylindrical or other shaped cylinder 12 extending toward the mold apparatus 101, a screw 13 disposed inside the cylinder 12 with its central axis parallel to the cylinder 12 and with flights spiraling around its periphery, a band-like or other shaped heater 14 disposed around the outer periphery of the cylinder 12, and a motor box 15 disposed behind the cylinder 12 and the screw 13. Although not shown, the motor box 15 contains a metering motor that rotates the screw 13 about its central axis to accumulate a predetermined amount of molding material Mm at the tip of the cylinder 12, an injection motor that moves the screw 13 forward and backward in directions approaching and away from the mold apparatus 101, a pressure detection sensor that detects the pressure that the screw 13 receives from the molding material Mm, and other components.

[0051] In this case, the direction approaching the fixed platen 32a of the mold clamping unit 31 to which the fixed mold 102 of the mold device 101 is attached is defined as the front side, and the direction moving away from the fixed platen 32a is defined as the rear side. Looking at the injection unit 11 located to the right of the fixed platen 32a in Fig. 1, the left direction approaching the fixed platen 32a is the front side, and the right direction moving away from the fixed platen 32a is the rear side.

[0052] The cylinder 12 is provided with a supply port 12a on the rear side, in front of the motor box 15, to which a hopper can be attached for feeding the molding material Mm into the cylinder 12. A nozzle 12b, the cross-sectional area of ​​which decreases on the front side, is provided at the tip of the cylinder 12 close to the mold device 101. A water-cooled cylinder 12c, such as a water-cooled cylinder, can be provided near the supply port 12a.

[0053] The heater 14, which is disposed around the cylinder 12 including the nozzle 12b, can be divided into a plurality of sections in the axial direction of the cylinder as shown in the figure, so that the inside of the cylinder 12 inside each heater section can be heated to a different temperature. Each heater section can be provided with a temperature detector.

[0054] Although not shown, a backflow prevention ring may be disposed around a constricted portion formed by partially reducing the outer diameter of the tip of the screw 13 to prevent the molding material Mm, which has been sent forward as it moves forward and backward together with the screw 13, from flowing backward toward the rear. This backflow prevention ring displaces back and forth relative to the screw 13 in response to the pressure it receives from the molding material Mm located forward or backward from it, thereby allowing only the flow of molding material Mm from the rearward side toward the front.

[0055] In the injection device 11 having such a configuration, the molding material Mm introduced into the cylinder 12 from the supply port 12a is heated by the heater 14 on the outer periphery of the cylinder 12 and melted by the rotation of the screw 13 driven by the metering motor during the metering process, and is sent forward inside the cylinder 12 to be accumulated at the tip of the cylinder 12. At this time, the screw 13 is displaced backward by the injection motor, forming a space at the tip of the cylinder 12 in which the molding material Mm can be accumulated.

[0056] Then, in the filling step, the screw 13 is displaced forward, so that the molding material Mm at the tip of the cylinder 12 is injected through the nozzle 12b toward the mold device 101. Furthermore, in the subsequent pressure holding step, pressure is applied to the molding material Mm that has filled the cavity of the mold device 101 through the molding material Mm remaining at the tip of the cylinder 12. At this time, it is possible to replenish the molding material Mm that has become deficient in the cavity of the mold device 101 due to the molding material Mm shrinking upon cooling.

[0057] Although this injection molding machine 1 is an inline screw type, it can also be a pre-plasticization type injection molding machine in which the plasticizing cylinder and plasticizing screw are structurally and functionally separated from the injection cylinder and injection plunger.

[0058] (Mobile device) The moving device 21 is provided, for example, below the motor box 15 of the injection device 11, and is an advance / retract drive mechanism for displacing the injection device 11 forward and backward relative to the fixed platen 32a. Various mechanisms can be used as the forward / backward drive mechanism that constitutes the moving device 21, but the moving device 21 shown in the figure is configured to include a hydraulic or other hydraulic pump 22, a pump operation motor 23 that is electric or other such that operates the hydraulic pump 22, and a double-acting hydraulic cylinder 24 that receives hydraulic fluid from the hydraulic pump 22 and causes a piston rod, the tip of which is fixed to a fixed platen 32a, to perform an extension / retraction motion.

[0059] The moving device 21 further includes a slide base 25 to which the above-mentioned hydraulic pump 22, pump actuation motor 23, and hydraulic cylinder 24 are attached, and a guide 26 that is laid on the base frame 2 to guide the linear movement of the slide base 25. Thereby, the injection unit 11 placed on the slide base 25 can be moved forward and backward.

[0060] The moving device 21 makes it possible to move the injection device 11 away from the mold device 101, or to move the injection device 11 closer to the mold device 101 and press the nozzle 12b of the cylinder 12 of the injection device 11 against the mold device 101 with a predetermined pressure, thereby performing a so-called nozzle touch.

[0061] (Injection molding operation) The control device can execute the following injection molding operations to produce a molded part.

[0062] With a predetermined amount of molding material Mm already measured and placed inside the injection unit 11 during the latter half of the previous molding, the mold closing process is carried out using the mold clamping unit 31 to place the mold device 101 in a mold closed state, and a pressure increase process and mold clamping process are carried out to press the movable mold 103 against the fixed mold 102 until a predetermined mold clamping force is applied.

[0063] Next, the screw 13 is advanced to inject the molding material Mm into the mold device 101, thereby filling the cavity in the mold device 101 with the molding material Mm in a filling process, and the screw 13 is advanced further to maintain the molding material Mm inside the tip of the injection device 11 at a predetermined pressure in this order. At this time, the mold clamping compression described above can be carried out.

[0064] Then, a cooling step is performed in which the molding material Mm filled in the cavity of the mold device 101 is cooled and solidified to obtain a molded product. At this time, a measuring step is performed in which the molding material Mm separately charged into the injection device 11 is melted while being fed toward the tip of the injection device 11 by the rotation of the screw 13 under heating by the heater 14, and a predetermined amount of the molding material Mm is placed at the tip.

[0065] Furthermore, after that, the mold clamping device 31 is operated to perform a depressurization process to reduce the clamping force on the mold device 101, and a mold opening process to open the mold device 101, and then an ejector device 41 is used to perform an ejection process to remove the molded product from the mold device 101. [Explanation of symbols]

[0066] 1 injection molding machine 2 base frame 11 Injection device 12 cylinders 12a Supply port 12b nozzle 12c water-cooled cylinder 13 Screw 14 Heater 15 Motor box 21 Mobile Devices 22 Hydraulic pump 23 Pump operating motor 24 Hydraulic Cylinder 25 Slide Base 26 Guide 31 Mold clamping device 32 Platen 32a Fixed Platen 32b Movable platen 32c tie bar 32d Guide member 33 Platen operating mechanism 34 Rear platen 35 Mold clamping motor 36 Motion conversion mechanism 36a Screw shaft 36b Nut 37 Toggle mechanism 37a~37c Link 37d Crosshead 38 Mold thickness adjustment motor 41 Ejector device 101 Mold equipment 102 Fixed mold 103 Movable mold 104 Movable parts 105a Projecting plate 106 Movable side mounting plate 107 Spacer Block 108 Receiving plate 108a Elastic member 109 Movable side template 109a Material pressing member 109b Pressure member Gate 109c 110 Fixed side mounting plate 111 Fixed side template 112 Sprue bushing 112a sprue Mm molding material Se Space Si internal space

Claims

1. A control device for an injection molding machine to which a mold device is attached, the mold device has a movable mold and a fixed mold, In the injection molding machine, the movable mold of the mold device moves from a mold open position toward an injection start position, injects a molding material into an internal space of the mold device, and the movable mold further moves from the injection start position to a mold clamping completion position to perform mold clamping compression, compressing the molding material; The control device controls the movement of the movable mold so that the moving speed of the movable mold is decelerated during the movement of the movable mold from the mold open position to the injection start position.

2. 2. The control device according to claim 1, wherein the control device accelerates the moving speed of the movable mold when the movable mold starts to move from the mold open position to the injection start position, and then decelerates the moving speed of the movable mold as the movable mold approaches the injection start position after the acceleration.

3. The control device according to claim 1 , wherein the control device gradually reduces the moving speed of the movable mold as the movable mold approaches the injection start position.

4. An injection molding machine comprising the control device according to any one of claims 1 to 3.

5. An injection molding system comprising: the injection molding machine according to claim 4; and a mold device attached to the injection molding machine.

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