Injection molding machine

Abstract

Provided is an injection molding machine capable of stabilizing the quality of a molded product. The injection molding machine includes a detector that detects the flow of a molding material within a mold device, and a control device that controls a compression operation that compresses the molding material within a cavity space in the mold device based on the detection result of the detector.

Description

[0001] This invention is a divisional application of Chinese Patent Application No. 201610865533.5, filed by the applicant on September 29, 2016, entitled "Injection Molding Machine". Technical Field

[0002] This application claims priority based on Japanese Patent Application No. 2015-191823, filed on September 29, 2015. The entire contents of that Japanese application are incorporated herein by reference.

[0003] This invention relates to an injection molding machine. Background Technology

[0004] Patent Document 1 describes an injection molding machine that performs a single injection process by advancing a screw in a heated cylinder to inject molten resin accumulated at the front end of the screw into a mold, and then, midway through the single injection process, applies compression pressure to the resin in the mold. This injection molding machine initiates the compression process when the measured advance distance of the screw reaches a preset value.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2002-113753

[0006] In the past, the effects of variations during injection, which occurred in processes other than compression, were sometimes amplified by the compression process, leading to greater variations in the quality of the molded product. Summary of the Invention

[0007] The present invention was made in view of the above-mentioned problems, and its main objective is to provide an injection molding machine that can stabilize the quality of molded articles.

[0008] To address the aforementioned issues, an injection molding machine is provided according to one aspect of the present invention, comprising:

[0009] Detector, used to detect the flow of molding material within the mold assembly; and

[0010] The control device controls the compression action of the molding material within the cavity space of the mold device based on the detection result of the detector.

[0011] Invention Effects

[0012] According to one aspect of the present invention, an injection molding machine capable of stabilizing the quality of molded articles is provided. Attached Figure Description

[0013] Figure 1 This is a diagram showing the state of an injection molding machine at the end of mold opening according to one embodiment.

[0014] Figure 2This is a diagram showing the state of the injection molding machine during mold closing according to one embodiment.

[0015] Figure 3 This is a diagram showing the state inside the mold assembly before the compression action of an injection molding machine in one embodiment begins.

[0016] Figure 4 This is a diagram showing the state inside the mold assembly after the compression action of an injection molding machine according to one embodiment has ended.

[0017] Figure 5 This is a diagram showing the state of the injection molding machine during mold closing in a modified example.

[0018] In the diagram: 30-Mold device, 32-Fixed mold, 33-Moving mold, 34-Cavity space, 36-Compression component, 37-Detector, 40-Injection device, 41-Cylinder, 42-Nozzle, 43-Screw, 50-Intermediate device, 60-Ejection device, 90-Control device. Detailed Implementation

[0019] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, in which the same or corresponding structures are labeled with the same or corresponding symbols and the description is omitted.

[0020] Figure 1 This is a diagram showing the state of an injection molding machine at the end of mold opening according to one embodiment. Figure 2 This is a diagram showing the state of the injection molding machine during mold closing according to one embodiment. Figure 1 and Figure 2 For ease of explanation, the flow path of the molding material within the mold device 30 is simplified.

[0021] For example, such as Figure 1 and Figure 2 As shown, the injection molding machine includes a frame Fr, a mold clamping device 10, an injection device 40, an intermediate device 50, an ejection device 60, and a control device 90. The intermediate device 50 may be included in the mold assembly 30 or may not be included in the injection molding machine.

[0022] First, the mold clamping device 10, the intermediate device 50, and the ejection device 60 will be explained. In the explanation of the mold clamping device 10, etc., the direction of movement of the movable pressure plate 13 during mold closing will be described ( Figure 1 and Figure 2 The direction of movement of the movable pressure plate 13 during mold opening is set as the front (center to the right). Figure 1 and Figure 2 (The middle direction is to the left) is used to explain the rear direction.

[0023] The mold closing device 10 performs mold closing, mold clamping, and mold opening of the mold device 30. The mold closing device 10 includes a fixed pressure plate 12, a movable pressure plate 13, a supporting pressure plate 15, a connecting rod 16, a toggle mechanism 20, a mold closing motor 21, and a motion conversion mechanism 25.

[0024] The fixed pressure plate 12 is fixed to the frame Fr. A fixed mold 32 is installed on the surface of the fixed pressure plate 12 opposite to the movable pressure plate 13.

[0025] The movable pressure plate 13 moves freely along the guide (e.g., guide rail) 17 laid on the frame Fr, and can move freely forward and backward relative to the fixed pressure plate 12. A movable mold 33 is mounted on the surface of the movable pressure plate 13 opposite to the fixed pressure plate 12 via an intermediate device 50.

[0026] Mold closing, mold assembly, and mold opening are achieved by moving the movable pressure plate 13 forward and backward relative to the fixed pressure plate 12. The mold assembly 30 consists of the fixed mold 32 and the movable mold 33.

[0027] The support plate 15 is connected to the fixed plate 12 at a distance and is mounted on the frame Fr, which is movable freely in the mold opening and closing direction. Additionally, the support plate 15 can also move freely along the guide members laid on the frame Fr. The guide members of the support plate 15 can be interchangeable with the guide members 17 of the movable plate 13.

[0028] In addition, in this embodiment, the fixed pressure plate 12 is fixed to the frame Fr, and the supporting pressure plate 15 can move freely relative to the frame Fr in the mold opening and closing direction. However, it is also possible that the supporting pressure plate 15 is fixed to the frame Fr, and the fixed pressure plate 12 can move freely relative to the frame Fr in the mold opening and closing direction.

[0029] Connecting rods 16 connect the fixed pressure plate 12 and the supporting pressure plate 15 at intervals. Multiple connecting rods 16 can be used. Each connecting rod 16 is parallel to the mold opening and closing direction and extends according to the mold closing force. At least one connecting rod 16 is equipped with a mold closing force detector 18. The mold closing force detector 18 can be a strain gauge, which detects the mold closing force by detecting the strain of the connecting rod 16.

[0030] In addition, the clamping force detector 18 is not limited to strain gauges, but can also be piezoelectric, capacitive, hydraulic, electromagnetic, etc., and its installation position is not limited to the connecting rod 16.

[0031] A toggle mechanism 20 is disposed between the movable pressure plate 13 and the supporting pressure plate 15. The toggle mechanism 20 consists of a crosshead 20a and multiple connecting rods 20b, 20c, etc. One connecting rod 20b is oscillatingly mounted on the movable pressure plate 13, and the other connecting rod 20c is oscillatingly mounted on the supporting pressure plate 15. These connecting rods 20b, 20c are connected by pins or the like to allow for free extension and retraction. By moving the crosshead 20a forward and backward, the multiple connecting rods 20b, 20c extend and retract, and the movable pressure plate 13 moves forward and backward relative to the supporting pressure plate 15.

[0032] The clamping motor 21 is mounted on the support plate 15, and moves the movable plate 13 forward and backward by moving the crosshead 20a. A motion conversion mechanism 25 is provided between the clamping motor 21 and the crosshead 20a to convert the rotational motion of the clamping motor 21 into linear motion and transmit it to the crosshead 20a. The motion conversion mechanism 25 is, for example, a ball screw mechanism. The position and speed of the crosshead 20a are detected, for example, by an encoder 21a of the clamping motor 21.

[0033] The operation of the mold closing device 10 is controlled by the control device 90. The control device 90 controls the mold closing process, the mold closing process, and the mold opening process, etc.

[0034] During the mold closing process, the movable pressure plate 13 is advanced by driving the mold closing motor 21, thereby bringing the moving mold 33 into contact with the fixed mold 32. A compression member 36 is arranged on the side of the moving mold 33, and the compression member 36 can move freely in and out of the mold device 30.

[0035] During the mold closing process, a closing force is generated by further driving the mold closing motor 21. During mold closing, a cavity space 34 is formed between the compression member 36 located on the moving mold 33 side and the fixed mold 32, and the cavity space 34 is filled with liquid molding material. Within the cavity space 34, the molding material is compressed by the compression member 36. The molding material within the cavity space 34 is then solidified to form a molded product.

[0036] During the mold opening process, the movable pressure plate 13 is retracted by driving the mold closing motor 21, thereby separating the moving mold 33 from the fixed mold 32.

[0037] In addition, the mold clamping device 10 of this embodiment has a mold clamping motor 21 as a drive source, but a hydraulic cylinder may be used instead of the mold clamping motor 21. Furthermore, the mold clamping device 10 may have a linear motor for mold opening and closing, or it may have an electromagnet for mold clamping.

[0038] An intermediate device 50 is disposed between the moving mold 33 and the movable pressure plate 13. The intermediate device 50 has, for example, a block 51. The rear end of the compression member 36 is inserted into the internal space 52 of the block 51.

[0039] Ejection device 60 ejects the molded article from mold assembly 30 after mold opening. Ejection device 60 includes, for example, an ejection motor 61, a motion conversion mechanism 62, and an ejection rod 63.

[0040] The ejector motor 61 is mounted behind the movable pressure plate 13. The ejector motor 61 has an encoder 61a. The encoder 61a detects the rotation angle of the output shaft of the ejector motor 61 and outputs a signal representing the rotation angle to the control device 90.

[0041] The motion conversion mechanism 62 converts the rotary motion of the ejector motor 61 into the linear motion of the ejector rod 63. The motion conversion mechanism 62 is, for example, composed of a ball screw mechanism.

[0042] The ejector rod 63 moves freely in and out of the through hole of the movable pressure plate 13. The front end of the ejector rod 63 contacts the rear end face of the ejector plate 64.

[0043] The ejector plate 64 moves freely within the internal space 52 of the block 51. The front end face of the ejector plate 64 contacts the rear end of the compression member 36.

[0044] The ejector rod 63 is advanced by driving the ejector motor 61, thereby advancing the compression component 36. Conversely, the ejector rod 63 is retracted by driving the ejector motor 61, thereby retracting the compression component 36.

[0045] The ejection device 60 functions as a drive device for the compression component 36. The compression component 36 is used for the following two purposes: (1) compressing the molding material within the mold device 30; and (2) ejecting the molded article from the mold device 30.

[0046] Next, the injection device 40 will be described. In the description of the injection device 40, unlike the description of the mold clamping device 10, the direction of movement of the screw 43 during filling will be explained (…). Figure 1 and Figure 2 The direction of movement of the screw 43 during measurement is set as the forward direction (leftward). Figure 1 and Figure 2 (The middle direction is to the right) is used to explain the rear direction.

[0047] The injection device 40 is mounted on a slide Sb that moves freely forward and backward relative to the frame Fr, and also moves freely forward and backward relative to the mold assembly 30. The injection device 40 contacts the mold assembly 30 and fills the mold assembly 30 with molding material.

[0048] The injection device 40 includes, for example, a cylinder 41, a nozzle 42, a screw 43, a metering motor 45, an injection motor 46, and a pressure detector 47.

[0049] The cylinder 41 heats the molding material supplied into it from the supply port 41a. The supply port 41a is formed at the rear of the cylinder 41. A heating source, such as a heater, is provided on the outer periphery of the cylinder 41.

[0050] The nozzle 42 is located at the front end of the cylinder 41 and is pressed against the mold device 30.

[0051] The screw 43 is configured to rotate freely and move forward and backward within the cylinder 41.

[0052] The metering motor 45 rotates the screw 43, thereby feeding the molding material forward along the spiral grooves of the screw 43. As the molding material is fed forward, it gradually melts due to heat from the cylinder 41. As the liquid molding material is fed forward to the screw 43 and accumulates in the front of the cylinder 41, the screw 43 retracts.

[0053] The injection motor 46 moves the screw 43 forward and backward. By advancing the screw 43, the injection motor 46 injects the liquid molding material accumulated in front of the screw 43 from the cylinder 41 and fills the mold assembly 30. Then, the injection motor 46 presses the screw 43 forward, thereby applying pressure to the molding material within the mold assembly 30. This replenishes any insufficient molding material. A motion conversion mechanism is provided between the injection motor 46 and the screw 43 to convert the rotational motion of the injection motor 46 into the linear motion of the screw 43.

[0054] A pressure detector 47 is disposed, for example, between the injection motor 46 and the screw 43, and detects the pressure on the screw 43 from the molding material and the back pressure on the screw 43. The pressure on the screw 43 from the molding material corresponds to the pressure exerted by the screw 43 on the molding material.

[0055] The operation of the injection device 40 is controlled by the control device 90. The control device 90 controls the filling process, the pressure holding process, and the metering process, etc.

[0056] In the filling process, the injection motor 46 drives the screw 43 to advance at a set speed, filling the mold assembly 30 with the liquid molding material accumulated in front of the screw 43. The position and speed of the screw 43 are detected, for example, by an encoder 46a of the injection motor 46. If the screw 43 reaches a predetermined position, the process switches from the filling process to the holding pressure process (so-called V / P switching). The set speed of the screw 43 can be changed according to the position and time of the screw 43.

[0057] Additionally, during the filling process, after the screw 43 reaches a predetermined position, it can be temporarily stopped at that position before V / P switching. Before V / P switching, the screw 43 can be moved forward or backward at a slight speed instead of stopping. When any of these actions are performed—stopping, moving forward at a slight speed, or moving backward at a slight speed—the molding material mainly flows through residual pressure, thus reducing peak pressure and suppressing burr formation.

[0058] During the holding pressure process, the injection motor 46 is driven to press the screw 43 forward at a set pressure, applying pressure to the molding material within the mold assembly 30. This replenishes any insufficient molding material. The pressure of the molding material is detected, for example, by a pressure detector 47. During the holding pressure process, the molding material within the mold assembly 30 is gradually cooled, and at the end of the holding pressure process, the entrance to the cavity space 34 is blocked by the solidified molding material. This state is called a gate seal, preventing the molding material from flowing back from the cavity space 34. After the holding pressure process, a cooling process begins. During the cooling process, the molding material within the cavity space 34 solidifies. To shorten the molding cycle, a metering process can also be performed during the cooling process.

[0059] In the metering process, the screw 43 is rotated at a set speed by driving the metering motor 45, and the molding material is fed forward along the spiral grooves of the screw 43. As a result, the molding material gradually melts. The screw 43 then retracts as the molten molding material is fed forward and accumulates at the front of the cylinder 41. The rotational speed of the screw 43 is detected, for example, by an encoder 45a of the metering motor 45.

[0060] In the metering process, to limit the rapid retraction of the screw 43, a set back pressure can be applied to the screw 43 by driving the injection motor 46. The back pressure applied to the screw 43 is detected, for example, by a pressure detector 47. The metering process ends when the screw 43 retracts to a predetermined position and a predetermined amount of molding material accumulates in front of the screw 43.

[0061] like Figure 1 and Figure 2 As shown, the control device 90 includes a CPU (Central Processing Unit) 91 and a storage medium 92 such as a memory. The control device 90 controls the mold clamping device 10, the injection device 40, and the ejection device 60 by causing the CPU 91 to execute the program stored in the storage medium 92.

[0062] Figure 3 This is a diagram showing the state inside the mold assembly before the compression action of an injection molding machine in one embodiment begins. Figure 3 The direction of the middle arrow indicates the flow direction of the molding material. Figure 4This is a diagram showing the state inside the mold assembly after the compression action of an injection molding machine according to one embodiment has ended. Figure 4 The direction of the middle arrow indicates the compression direction based on the compression component 36.

[0063] The control device 90 controls the compression action (hereinafter referred to as "compression action") of the molding material M within the cavity space 34. The compression action is performed, for example, by advancing the compression member 36.

[0064] like Figure 3 and Figure 4 As shown, the compression action can begin midway through the filling process or before the flow tip of the molding material reaches the end of the flow path. Furthermore, the compression action can end approximately simultaneously with the end of the filling process or approximately simultaneously with the flow tip of the molding material reaching the end of the flow path.

[0065] Furthermore, there is no particular limitation on the start time of the compression action. For example, the compression action can begin after the pressure holding process has started. Similarly, there is no particular limitation on the end time of the compression action. For example, the compression action can end before the flow front of the molding material reaches the end of the flow path, or it can end after the flow front of the molding material reaches the end of the flow path.

[0066] A detector 37 is used to detect the flow of molding material M within the mold assembly 30 during the compression process. Additionally, the number of detectors 37 is... Figure 3 and Figure 4 There can be one detector, but there can also be multiple detectors. Multiple detectors 37 can be arranged at intervals along the flow path of the molding material M.

[0067] Detector 37 detects when the molding material M reaches a predetermined position. For example, detector 37 detects when the flow tip of the molding material reaches a predetermined position. In addition, detector 37 can detect when a predetermined amount of molding material reaches a predetermined position (e.g., cavity space 34).

[0068] Detector 37 may be a temperature sensor or a pressure sensor, for example. Both temperature sensors and pressure sensors can be used as detector 37.

[0069] When the molding material M reaches or is near the location of the temperature sensor, the temperature reading of the temperature sensor rises because the temperature of the molding material M is higher than the temperature of the mold assembly 30. The rise in the temperature sensor reading detects that the molding material M has reached a predetermined position. For example, if the temperature sensor reading exceeds a set value, it is considered that the molding material M has reached or is near the location of the temperature sensor. Alternatively, if the time derivative of the temperature sensor reading exceeds a set value, it is also considered that the molding material M has reached or is near the location of the temperature sensor.

[0070] When the molding material M reaches the set position of the pressure sensor, the pressure sensor reading rises due to the pressure exerted by the molding material M. The rise in the pressure sensor reading indicates that the molding material M has reached a predetermined position. For example, if the pressure sensor reading exceeds a set value, the molding material M is considered to have reached the set position. Alternatively, if the time derivative of the pressure sensor reading exceeds a set value, the molding material M is considered to have reached the set position.

[0071] Furthermore, as the detector 37, a pressure sensor 66 that detects the pressure acting on the component performing the compression action and a position sensor 65 that detects the position of the component performing the compression action can be used. This is because when the molding material M reaches the cavity space 34, the component performing the compression action is pressed down. Examples of components performing the compression action include the compression component 36, the ejector rod 63, and the ejector plate 64.

[0072] In this embodiment, the component performing the compression action also serves as the ejection component, but the compression component and the ejection component can also be provided separately. In this case, as the detector 37, a pressure sensor that detects the pressure acting on the ejection component and a position sensor that detects the position of the ejection component can also be used. This is because the ejection component is pressed when the molding material M reaches the cavity space 34.

[0073] The control device 90 controls the compression action based on the detection results of the detector 37. By adjusting the compression action according to the filling status of the molding material within the mold assembly 30, variations from processes other than compression (such as metering and filling processes) can be absorbed. Therefore, the quality of the molded product can be stabilized.

[0074] The control device 90 initiates the compression operation based on the detection results of the detector 37. The timing of initiating the compression operation is adjusted according to the filling status of the molding material in the mold device 30, thereby absorbing variations in processes other than the compression operation.

[0075] For example, the compression action can begin when the control device 90 detects, based on the detection result of the detector 37, that the molding material M has reached a predetermined position, and the elapsed time from that point reaches a preset compression action start time. Variations in the timing of the molding material M reaching the predetermined position can be absorbed, and fluctuations in peak pressure can be suppressed. The compression action start time corresponds to the preset time described in the claims.

[0076] Furthermore, the compression action can be initiated when the control device 90 detects the flow front position of the molding material M based on the detection result of the detector 37, and this detected position reaches a preset compression action start position. The detection of the flow front position of the molding material M can be performed by measuring, for example, the elapsed time since the molding material M reached the specified position. As time elapses, the flow front position of the molding material M gets closer to the end of the flow path.

[0077] Furthermore, the compression action can be initiated at a time corresponding to the required time from the start of the filling process until the molding material M reaches the specified position. For example, the longer the required time, the slower the flow of the molding material; therefore, the compression action can be initiated at a slightly slower time from the start of the filling process.

[0078] Additionally, detector 37 in Figure 3 and Figure 4 The detector 37 can be disposed upstream of the entrance to the cavity space 34, but it can also be disposed downstream of the entrance to the cavity space 34. In this case, the start time of the aforementioned compression action can be zero. Furthermore, the detector 37 can be disposed on both sides of the entrance to the cavity space 34.

[0079] The control device 90 can perform position control of the compression action after the compression action has started. This position control can control the position of the component performing the compression action. The control device 90 controls the compression action by setting the position of the component performing the compression action as the set position. This control can be either feedback control or feedforward control. Examples of components performing the compression action include the compression component 36, the ejector rod 63, and the ejector plate 64.

[0080] The position of the component performing the compression action is detected by position sensor 65. Position sensor 65 is mounted on a component on the fixed side (e.g., Figure 1 and Figure 2 The block 51 of the intermediate device 50 can be used, but it can also be a component mounted on the movable side. In addition, the encoder 61a of the ejector motor 61 can be used as the position detector 65.

[0081] The control device 90 can control the position of the compression action based on the detection result of the detector 37 after the compression action has started. The set position of the component performing the compression action can be changed according to the filling condition of the molding material M.

[0082] For example, the set position of the component performing the compression action can be changed according to the elapsed time since the molding material M reaches the specified position, as detected by the detector 37, or it can be changed at a speed corresponding to that elapsed time.

[0083] Furthermore, the position of the component performing the compression action can be changed according to the position of the flow front of the molding material M detected by the detector 37, or it can be changed at a speed corresponding to the flow front position.

[0084] Furthermore, the position of the component performing the compression action can be changed at a rate corresponding to the time required from the start of the filling process until the molding material M reaches the specified position. For example, the longer the required time, the slower the flow of the molding material M; therefore, the rate at which the position of the component performing the compression action is changed can be slower.

[0085] The control device 90 can perform pressure control of the compression action after the compression action has started. This pressure control controls the pressure acting on the component performing the compression action. The pressure acting on the component performing the compression action corresponds to the pressure acting on the molding material M within the cavity space 34. Therefore, in the pressure control of the compression action, the pressure acting on the component performing the compression action can be controlled by controlling the pressure acting on the molding material M within the cavity space 34. The control device 90 controls the pressure acting on the component performing the compression action to reach a set pressure. This control can be either feedback control or feedforward control.

[0086] The pressure acting on the component performing the compression action is detected by pressure sensor 66. Pressure sensor 66 is mounted on the movable side of the component (e.g., Figure 1 and Figure 2 The compression component 36 can be installed on the middle side, but it can also be installed on a component on the fixed side (e.g., the fixed mold 32). Furthermore, the pressure sensor 66 can detect the pressure acting on the component performing the compression action by detecting the strain of the components of the ejection device 60 and the strain of the components of the intermediate device 50.

[0087] The control device 90 can control the pressure of the compression action based on the detection result of the detector 37 after the compression action begins. It can change the pressure acting on the component performing the compression action according to the filling status of the molding material M, and it can also change the pressure acting on the molding material.

[0088] For example, the set pressure of the component performing the compression action can be changed according to the elapsed time from when the molding material M reaches the specified position, as detected by the detector 37, or it can be changed at a speed corresponding to that elapsed time.

[0089] Furthermore, the set pressure of the component performing the compression action can be changed according to the position of the flow front of the molding material M detected by the detection result of the detector 37, or it can be changed at a speed corresponding to the position of the flow front.

[0090] Furthermore, the set pressure of the component performing the compression action can be changed at a rate corresponding to the time required from the start of the filling process until the molding material M reaches the specified position. For example, the longer the required time, the slower the flow of the molding material M; therefore, the rate at which the set pressure of the component performing the compression action is changed can be slower.

[0091] The control device can switch between position control and pressure control midway through the compression process. It can switch between position control and pressure control, or vice versa.

[0092] For example, the control device 90 performs position control, pressure control and position control sequentially in the compression operation process (hereinafter referred to as the "compression process").

[0093] The control device 90 performs position control at the very beginning of the compression process, thereby reliably advancing the compression member 36 to the set position and allowing the molding material M to diffuse on the front surface of the compression member 36. Furthermore, at the start of the compression process, the pressure of the molding material M within the cavity space 34 is unstable. By performing position control at the very beginning, the quality of the molded product is stabilized.

[0094] The control device 90 controls the pressure midway through the compression process, thereby ensuring that the molding material M is fully pressed against the wall of the cavity space 34, improving its transferability. Furthermore, because the pressure on the molding material M is stable, the density of the molding material M is also stable.

[0095] The control device 90 performs position control at the end of the compression process, thereby stabilizing the final size and shape of the cavity space 34 and the size and shape of the molded product. Finally, by advancing the compression component 36, the cavity space 34 is filled with the molding material M, thus ending the filling of the molding material M. A pressure holding process and a cooling process are performed after the filling process.

[0096] After the compression process is completed, position control can continue to prevent changes in the size of the cavity space 34 during the pressure holding and cooling processes. During this position control, movement of the compression component 36 is prohibited. This position control can continue until the start of the mold opening process.

[0097] Furthermore, in the compression process of this embodiment, position control, pressure control, and position control are performed sequentially, but the number of switching operations and the order of switching are not particularly limited. For example, the number of switching operations can be once, or it can be that only position control and pressure control are performed sequentially, or it can be that only pressure control and position control are performed sequentially. Moreover, the number of switching operations can be three or more.

[0098] The control device 90 can switch between position control and pressure control of the compression action based on the detection results of the detector 37. The switching timing can be changed according to the filling status of the molding material M.

[0099] The switching of the compression action control mode can be performed, for example, when the control device 90 detects that the molding material M has reached the specified position based on the detection result of the detector 37, and the elapsed time since that arrival reaches the preset switching time.

[0100] Furthermore, the switching of the compression action control mode can be performed when the control device 90 detects the flow front position of the molding material M based on the detection result of the detector 37, and the detection position reaches the preset switching position.

[0101] After the control device 90 reduces the forward speed of the screw 43 midway through the filling process, it can control the compression action based on the detection results of the detector 37. After the forward speed of the screw 43 decreases, the molding material mainly flows through residual pressure, etc. Therefore, it is difficult to grasp the filling status of the molding material in the mold device 30 from the position of the screw 43. Therefore, the effect of grasping the filling status of the molding material in the mold device 30 through the detector 37 can be significantly achieved.

[0102] The above describes the implementation methods of the injection molding machine, but the present invention is not limited to the above-described implementation methods. Various modifications and improvements can be made within the scope of the spirit of the present invention as set forth in the claims.

[0103] For example, the compression member 36 in the above embodiment is used for the following two purposes: (1) compressing the molding material in the mold device 30; and (2) ejecting the molded article from the mold device 30. Alternatively, it may be used only for (1) compression and not for (2) ejection. In this case, the ejection member and the compression member 36 are respectively disposed in the mold device 30.

[0104] When the ejector component and the compression component 36 are provided separately, the ejector device 60 can function as a drive device that independently drives both the ejector component and the compression component 36, or it can function as a drive device that only drives the ejector component. In the latter case, a separate drive device is provided for driving the compression component 36. For example, a hydraulic cylinder, which is an intermediate device 50, is used as a drive device for driving the compression component 36.

[0105] In the above embodiment, the compression member 36 is disposed on the moving mold 33 side, but it can also be disposed on the fixed mold 32 side. In this case, the intermediate device 50 can be disposed between the fixed mold 32 and the fixed pressure plate 12. Alternatively, the compression member 36 can be disposed on both sides of the moving mold 33 and the fixed mold 32 respectively.

[0106] In the above embodiments, the compression action of the molding material within the cavity space uses an ejector device 60, but a mold clamping device 10 can also be used. In the latter case, the intermediate device 50 may not be required, and a mold clamping device 10 can be used. Figure 5 The mold device 30A shown is used instead of the mold device 30.

[0107] The mold assembly 30A includes a fixed mold 32A and a movable mold 33A. The fixed mold 32A is mounted on the fixed pressure plate 12, and the movable mold 33A is not connected to the fixed pressure plate 12. Figure 1 The intermediate device 50 shown in the figure is mounted on the movable pressure plate 13.

[0108] like Figure 5 As shown, the moving mold 33A has a mold body portion 33Aa, a frame-shaped portion 33Ab, and a spring portion 33Ac. The mold body portion 33Aa is mounted on the movable pressure plate 13. The frame-shaped portion 33Ab surrounds the protrusion of the mold body portion 33Aa and is connected to the mold body portion 33Aa via the spring portion 33Ac.

[0109] The mold clamping device 10 advances the movable pressure plate 13, pressing the frame-shaped portion 33Ab against the fixed mold 32A, causing the spring portion 33Ac to contract. The mold body portion 33Aa advances to a predetermined position, forming a cavity space 34A between the mold body portion 33Aa and the fixed mold 32A. Next, the mold clamping device 10 further advances the movable pressure plate 13, compressing the molding material within the cavity space 34A.

[0110] in addition, Figure 5 In the moving mold 33A, there is a mold body part 33Aa, a frame-shaped part 33Ab, and a spring part 33Ac. However, the fixed mold 32A can also be made to have these parts instead of the moving mold 33A. Furthermore, Figure 5 The connecting part between the main body of the mold 33Aa and the frame-shaped part 33Ab is a spring, but a cylinder or the like can also be used. Furthermore, one of the moving mold 33A and the fixed mold 32A has a protrusion, and the other of the moving mold 33A and the fixed mold 32A has a recess. The protrusion is inserted into the recess, and a cavity space can be formed between the top surface of the protrusion and the bottom surface of the recess.

[0111] The injection device 40 in the above embodiment is a coaxial screw type, but it can also be a pre-plasticizing type. In the pre-plasticizing type injection device, the molding material molten in the plasticizing cylinder is supplied to the injection cylinder, and the molding material is injected from the injection cylinder into the mold device. The screw is arranged in the plasticizing cylinder in a rotatable or rotatable and retractable manner, and the plunger is arranged in the injection cylinder in a retractable manner.

Claims

1. An injection molding machine, comprising: Detector, used to detect the flow of molding material within the mold assembly; and The control device controls the timing of the compression action of compressing the molding material within the cavity space of the mold device based on the detection result of the detector. The detector is positioned upstream of the entrance to the cavity space to detect the arrival of the molding material. The compression action is performed when the elapsed time from the arrival time reaches the preset compression action start time.

2. The injection molding machine according to claim 1, wherein, The control device initiates the compression action based on the detection result of the detector.

3. The injection molding machine according to claim 1 or 2, wherein, The control device detects the arrival of the molding material at the specified position based on the detection result of the detector.

4. The injection molding machine according to any one of claims 1 to 3, wherein, The control device detects the arrival of the flow front end of the molding material at a predetermined position based on the detection result of the detector.

5. The injection molding machine according to claim 3 or 4, wherein, The control device initiates the compression action when it detects that the elapsed time from the arrival point has reached a set time.

6. The injection molding machine according to any one of claims 1 to 5, wherein, The control device performs position control based on the detection result of the detector, and this position control controls the position of the component performing the compression action.

7. The injection molding machine according to any one of claims 1 to 6, wherein, The control device performs pressure control based on the detection results of the detector, and the pressure control controls the pressure acting on the component performing the compression action.

8. The injection molding machine according to any one of claims 1 to 7, wherein, The control device switches between position control and pressure control of the compression action based on the detection results of the detector.

9. The injection molding machine according to claim 1, wherein, The control device performs position control at the very beginning of the compression process and pressure control during the middle of the compression process.

10. The injection molding machine according to claim 9, wherein, The control device performs position control at the end of the compression process.

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