Computing device and injection molding system

Abstract

The present invention relates to an arithmetic device. An arithmetic device (72) of one embodiment adjusts a speed ratio of a first moving speed of an ejection rod (54) and a second moving speed of a movable table (34) or a holding device (18) in a manner such that the magnitude of a load received by the holding device (18) from a molded article in a synchronous operation is within a prescribed range.

Description

Technical Field

[0001] This invention relates to the calculation of parameters used in injection molding machines. Background Technology

[0002] Injection molding machines eject and remove molded articles from a mold. Japanese Patent Application Publication No. 2001-150496 discloses a method for removing molded articles from a mold. In this method, during the retraction of the moving mold side, an ejector pin housed inside the moving mold side is advanced synchronously with the retraction speed of the moving mold side. According to this method, since the molded article remains at the same position on the base of the device, it is possible to remove the molded article in parallel with the retraction action of the moving mold side by a gripping device (conveyor). As a result, the operation time required to remove the molded article can be shortened. Summary of the invention

[0003] However, for example, when the elastic modulus (elastic modulus) of the molded part is relatively small, the relative position of the molded part and the tip of the ejector pin changes. In this case, even if the ejector pin and the moving mold advance at the same speed, the molded part will not remain at the same position on the base of the device. Therefore, it is possible to apply excessive load to the holding device that holds the molded part. Summary of the Invention The problem the invention aims to solve

[0004] The purpose of this invention is to solve the above-mentioned problems.

[0005] The first aspect of the present invention is a computing device for calculating parameters used in an injection molding machine, which performs a synchronous operation that synchronizes an opening action that opens the movable mold in the mold opening direction or a pulling action that pulls a holding device holding the molded article in the mold closing direction of the movable mold, and a protruding action that causes an ejector pin to protrude from the movable mold. The computing device includes: a load acquisition unit that acquires the load borne by the holding device from the molded article; and an adjustment unit that adjusts the speed ratio between a first moving speed of an ejector rod that drives the ejector pin in the mold closing direction and a second moving speed of a movable platform mounted on the movable mold or the holding device, such that the magnitude of the load acquired in the synchronous operation is within a predetermined range.

[0006] The second aspect of the present invention is an injection molding system comprising the aforementioned computing device, the aforementioned injection molding machine, and the aforementioned removal device having the aforementioned holding device.

[0007] According to the method of the present invention, even if the relative position of the ejector pin and the molded article changes during synchronous operation, it is possible to suppress the application of excessive load to the holding device holding the molded article. Attached Figure Description

[0008] Figure 1 This is a schematic diagram showing the structure of an injection molding system. Figure 2 This is a schematic diagram showing the structure of the protruding device. Figure 3 This is a diagram showing the state of the ejector pin protruding. Figure 4 It is a diagram showing the protruding shape of a molded product. Figure 5 It is a block diagram showing the components of an injection molding machine. Figure 6 This is a conceptual diagram representing the load applied when the forward speed is greater than the backward speed. Figure 7 This is a conceptual diagram representing the load applied when the backward speed is greater than the forward speed. Figure 8 It is a flowchart representing the computational processing flow of the computing device. Figure 9 This is a block diagram representing the arithmetic device of variation 3. Figure 10 This is a block diagram showing the structure of a part of the injection molding machine in Modified Example 4. Figure 11 This is a block diagram representing the injection molding system of variant 5. Figure 12 This is a block diagram representing the injection molding system of variant example 6. Detailed Implementation

[0009] [Implementation Method] Figure 1 This is a schematic diagram showing the configuration of the injection molding system 10. The injection molding system 10 includes an injection molding machine 12 and a take-out device 14.

[0010] The injection molding machine 12 is a machine for molding articles. The injection molding machine 12 can be a horizontal injection molding machine that can be set on a setting surface that extends in a horizontal direction, or a vertical injection molding machine that can be set on a setting surface that extends in a direction intersecting the horizontal. Figure 1 This is an example of when injection molding machine 12 is a horizontal injection molding machine.

[0011] The injection molding machine 12 repeatedly molds the part in each cycle. In one cycle, the injection molding machine 12 performs the following actions: mold closing, injection, pressure holding, metering, mold opening, and ejection.

[0012] The mold closing action is the action of closing the mold 16. The injection action is the action of injecting molding material into the cavity of the mold 16. The holding pressure action is the action of applying pressure to the molding material injected into the cavity of the mold 16. The metering action is the action of metering the molding material in preparation for the next molding cycle. The mold opening action is the action of opening the mold 16. The ejection action is the action of ejecting the molded part from the mold 16.

[0013] The extraction device 14 is a device for holding and removing the molded article. The extraction device 14 performs both a holding action and an extraction action. The holding action is the action of holding the molded article. The holding action is generally performed after the ejection action of the injection molding machine 12, but in this embodiment, it is performed before the ejection action of the injection molding machine 12. The extraction action is the action of removing the molded article from the mold 16. The extraction action is performed after the ejection action of the injection molding machine 12.

[0014] In this embodiment, a robot is used as the extraction device 14, but it is not limited to a robot. The extraction device 14 has a gripping device 18 that performs gripping actions. The gripping device 18 is also called an end effector. The gripping device 18 can be a device that uses fingers or claws to clamp the molded article, or it can be a device that uses negative pressure or magnetism to attract the molded article.

[0015] The injection molding machine 12 has a mold 16, a mold closing device 20, an injection device 22, a ejection device 24, and a control device 26.

[0016] Mold 16 is a template used to mold an article. Mold 16 has a fixed mold 28 and a movable mold 30. The fixed mold 28 and the movable mold 30 are disposed between the fixed platen 32 and the movable platen 34 of the mold clamping device 20. The fixed mold 28 is disposed on the surface of the fixed platen 32 facing the movable platen 34. The movable mold 30 is disposed on the surface of the movable platen 34 facing the fixed platen 32.

[0017] The mold closing device 20 is a device that performs mold closing and mold opening actions. The mold closing device 20 has a fixed platform 32, a movable platform 34, a back platform 36, and multiple tie rods 38.

[0018] A fixed platform 32 and a back platform 36 are spaced apart on the machine base 40 of the injection molding machine 12. A plurality of tie rods 38 are arranged between the fixed platform 32 and the back platform 36. The tie rods 38 are arranged approximately parallel to each other, spaced apart. One end of each tie rod 38 is mounted on the fixed platform 32, and the other end of each tie rod 38 is mounted on the back platform 36. Each tie rod 38 passes through a movable platform 34.

[0019] A movable platform 34 is positioned between the fixed platform 32 and the back platform 36. The movable platform 34 is mounted on a sliding portion 44 that allows the guide rail 42 to slide. The guide rail 42 is mounted on the machine base 40 of the injection molding machine 12 in a state approximately parallel to the tie rod 38. The movable platform 34 can move in both the mold-closing direction DA and the mold-opening direction DB according to the sliding of the sliding portion 44.

[0020] When the mold closing device 20 performs the mold closing action, the movable platen 34 moves in the mold closing direction DA by the driving force transmitted from the second drive source. Based on the movement of the movable platen 34, the movable mold 30 is pressed against the fixed mold 28, thereby applying a mold closing force to the mold 16. On the other hand, when the mold closing device 20 performs the mold opening action, the movable platen 34 moves in the mold opening direction DB by the driving force transmitted from the second drive source. Based on this movement of the movable platen 34, the movable mold 30 separates from the fixed mold 28. The second drive source can be a motor or a compressor. The compressor can be a hydraulic compressor or a pneumatic compressor. In this embodiment, the case where the second drive source is a motor will be described.

[0021] The injection device 22 is a device that performs injection, pressure holding, and metering actions. The injection device 22 can be a linear screw type injection device or a plunger type injection device. Figure 1 This is an example of an injection device 22 being a linear screw type.

[0022] The injection unit 22 has a nozzle 46, a cylinder 48, a screw 50, and a hopper 52. The nozzle 46 is mounted at the end of the cylinder 48 facing the mold 16. The nozzle 46 communicates with the interior of the cylinder 48. The screw 50 is inserted into the interior of the cylinder 48. The hopper 52 is connected to the cylinder 48. Molding material is supplied from the hopper 52 into the interior of the cylinder 48.

[0023] The cylinder 48 and screw 50 extend toward the mold 16. The screw 50 is rotatable. Additionally, the screw 50 can advance toward the nozzle 46 and retract from the nozzle 46. When the injection device 22 performs an injection operation, the screw 50 advances within the cylinder 48 in a non-rotating state. When the injection device 22 performs a holding pressure operation, back pressure is applied to the screw 50. In this case, the screw 50 can be stationary. When the injection device 22 performs a metering operation, the screw 50 rotates within the cylinder 48 and retracts. Alternatively, the screw 50 can also retract in a non-rotating state.

[0024] The protruding device 24 is a device that performs the protruding action. Figure 2 This is a schematic diagram showing the configuration of the protruding device 24. The protruding device 24 includes an ejector rod 54, an ejector plate 56, and an ejector pin 58. The number of ejector rods 54 can be one or more. The number of ejector pins 58 can be one or more. Figure 2 This example illustrates the case where there is one ejector rod 54 and two ejector pins 58. Since the two ejector pins 58 have the same configuration, only one ejector pin 58 will be described below.

[0025] Ejector rod 54 and ejector plate 56 are disposed in a space formed inside the movable mold 30. Ejector rod 54 and ejector plate 56 are movable in both the mold closing direction DA and the mold opening direction DB.

[0026] Ejector pin 58 extends from the surface of ejector plate 56 facing the fixed mold 28 in the mold closing direction DA. Ejector pin 58 inserts into pin hole 60 formed along the mold closing direction DA of movable mold 30. Ejector pin 58 is fixed to ejector plate 56 and can move together with ejector plate 56 in the mold closing direction DA or the mold opening direction DB (see reference). Figure 2 and Figure 3 ).

[0027] The top of the ejector pin 58 at the start of the protrusion action is located in the pin hole 60 of the movable mold 30 (see reference). Figure 2 At the end of the protrusion action, the tip of the ejector pin 58 protrudes from the movable mold 30. That is, during the period from the start to the end of the protrusion action, the tip of the ejector pin 58 protrudes from the cavity surface 61 of the movable mold 30 toward the fixed mold 28 (see reference). Figure 3 Additionally, the cavity surface 61 of the movable mold 30 refers to the surface of the movable mold 30 that constitutes the cavity of the mold 16.

[0028] When the ejector device 24 performs the ejection action, the ejector rod 54 moves in the mold-closing direction DA by the driving force transmitted from the first drive source, pushing the ejector plate 56. The ejector plate 56 is pushed by the ejector rod 54 and moves in the mold-closing direction DA. As a result, the ejector pin 58 fixed on the ejector plate 56 protrudes from the movable mold 30, and the molded product leaves the movable mold 30 (see reference). Figure 4 The first drive source can be a motor or a compressor. The compressor can be a hydraulic compressor or a pneumatic compressor. In this embodiment, the case where the first drive source is a motor will be described.

[0029] After the ejector rod 54 completes its protruding action, it moves in the mold opening direction DB by the driving force transmitted from the first drive source. In this case, the ejector plate 56 moves in the mold opening direction DB by the elastic force of a spring (not shown). As a result, the ejector pin 58 fixed on the ejector plate 56 is pulled into the pin hole 60 of the movable mold 30.

[0030] The control device 26 controls the injection molding machine 12. The control device 26 controls the mold closing device 20, causing it to perform mold closing or opening actions. Additionally, the control device 26 controls the injection device 22, causing it to perform injection, pressure holding, or metering actions. Furthermore, the control device 26 controls the ejector device 24, causing it to perform ejection actions.

[0031] The mold opening and ejection actions are performed synchronously. That is, the control device 26 first causes the mold closing device 20 to perform a single mold opening action, ensuring space between the fixed mold 28 and the movable mold 30 for the holding device 18. After the single mold opening action, the ejection device 14 performs a holding action, and the molded article is held by the holding device 18. Then, the control device 26 causes the mold closing device 20 and the ejection device 24 to perform synchronous actions. That is, the control device 26 causes the mold closing device 20 to perform a second mold opening action, and causes the ejection device 24 to perform a ejection action. During the ejection action, the molded article is held by the holding device 18. Furthermore, in the synchronous action, the end time of the second mold opening action and the end time of the ejection action can be the same or different.

[0032] During the execution of the protruding action, the molded article is held by the holding device 18. During this period, the position of the holding device 18 can be either stationary or floating. A stationary state means that the position of the holding device 18 remains unchanged even when subjected to external force. On the other hand, a floating state means that the position of the holding device 18 can change according to external force.

[0033] Figure 5 This is a block diagram showing the configuration of a portion of the injection molding machine 12. The control unit 26 includes a motor control unit 62. The motor control unit 62 controls the motors installed in the injection molding machine 12. This motor control unit 62 includes a first motor control unit 64 and a second motor control unit 66.

[0034] The first motor control unit 64 controls the pin drive motor 68 installed in the protrusion device 24 to cause the protrusion device 24 to perform a protrusion action. The pin drive motor 68 is a first drive source for driving the ejector rod 54, which pushes the ejector pin 58 in the mold closing direction DA. The motor driving force generated by the drive of the pin drive motor 68 is transmitted to the ejector rod 54. With the motor driving force transmitted to the ejector rod 54, the ejector rod 54 pushes the ejector plate 56. As a result, the ejector pin 58, which is fixed on the ejector plate 56, moves in the mold closing direction DA. That is, the first motor control unit 64 drives the ejector rod 54 by controlling the pin drive motor 68, and moves the ejector pin 58 in the mold closing direction DA via the ejector plate 56.

[0035] The second motor control unit 66 controls the mold drive motor 70 installed in the mold closing device 20 to cause the mold closing device 20 to perform mold opening or mold closing operations. The mold drive motor 70 is a second drive source for driving the movable platen 34 on which the movable mold 30 is mounted. The motor driving force generated by driving the mold drive motor 70 is transmitted to the movable platen 34. By transmitting the motor driving force to the movable platen 34, the movable mold 30 mounted on the movable platen 34 moves in the mold closing direction DA or the mold opening direction DB. That is, the second motor control unit 66 drives the movable platen 34 by controlling the mold drive motor 70, causing the movable mold 30 mounted on the movable platen 34 to move in the mold closing direction DA or the mold opening direction DB.

[0036] The control device 26 in this embodiment also includes an arithmetic unit 72. The arithmetic unit 72 calculates parameters used in the prominent operation. The arithmetic unit 72 has an information processing unit 74 and a storage unit 76. The information processing unit 74 is configured as a processor such as a CPU or a GPU. The storage unit 76 includes volatile memory such as RAM and non-volatile memory such as ROM, flash memory, and hard disk. At least a portion of the storage unit 76 may also be disposed in the processor.

[0037] The information processing unit 74 includes a load acquisition unit 80, an adjustment unit 82, and a setting change unit 84. The load acquisition unit 80, adjustment unit 82, and setting change unit 84 can also be implemented by the information processing unit 74 processing a program stored in the storage unit 76. Alternatively, at least one of the load acquisition unit 80, adjustment unit 82, and setting change unit 84 can be implemented using an integrated circuit such as an ASIC or FPGA. Furthermore, at least one of the load acquisition unit 80, adjustment unit 82, and setting change unit 84 can also be configured using an electronic circuit containing discrete components.

[0038] The load acquisition unit 80 acquires the load borne by the holding device 18 holding the molded article during synchronous operation based on the signal output from the load acquisition sensor 90. Furthermore, the load acquisition unit 80 stores load information representing the acquired load in the storage unit 76. The load acquisition sensor 90 is provided in the take-up device 14. The load acquisition sensor 90 may also be provided in the holding device 18 included in the take-up device 14.

[0039] The load acquisition sensor 90 can also be a torque sensor that detects the torque of the extraction motor used to perform the extraction operation. In this case, the load acquisition unit 80 acquires the torque of the extraction motor during synchronous operation based on the signal output from the torque sensor.

[0040] The load acquisition sensor 90 can also be a current sensor that detects the current (drive current) output to the extraction motor used to perform the extraction operation. In this case, the load acquisition unit 80 acquires the current of the extraction motor during synchronous operation based on the signal output from the current sensor. The load acquisition unit 80 can also calculate and acquire the torque or voltage (drive voltage) of the extraction motor during synchronous operation based on the signal output from the current sensor.

[0041] The load acquisition sensor 90 can also be a position sensor that detects the position of the take-up motor used to perform the take-up action. In this case, the load acquisition unit 80 acquires the position of the take-up motor during synchronous operation based on the signal output from the position sensor. When the position of the holding device 18 that holds the molded article is in a floating state during the protrusion action, the load acquisition unit 80 can easily capture the position of the take-up motor during the protrusion action as the load borne by the holding device 18 from the molded article.

[0042] The load acquisition sensor 90 can also be a force sensor that detects the extraction load generated during the extraction operation. In this case, the load acquisition unit 80 acquires the extraction load during synchronous operation based on the signal output from the force sensor.

[0043] The load acquisition sensor 90 can also be a strain sensor that detects the strain of the molded article. In this case, the load acquisition unit 80 acquires the strain of the molded article during synchronous operation based on the signal output from the strain sensor.

[0044] The load acquisition sensor 90 can also be a pressure sensor that detects the pressure of fluids such as hydraulic pressure or air pressure applied to perform the extraction operation. In this case, the load acquisition unit 80 acquires the fluid pressure during synchronous operation based on the signal output from the pressure sensor.

[0045] The load acquisition unit 80 can acquire at least one of the above-mentioned torque, current, voltage, phase, extraction load, molded article strain, and fluid pressure as the load borne by the holding device 18 holding the molded article during synchronous operation. Furthermore, the load acquisition unit 80 can acquire physical quantities other than torque, current, voltage, phase, extraction load, molded article strain, and fluid pressure as the load borne by the holding device 18 holding the molded article during synchronous operation. In summary, the load acquisition unit 80 can acquire more than one physical quantity as the load borne by the holding device 18 holding the molded article during synchronous operation.

[0046] The load acquired by the load acquisition unit 80 varies according to the speed ratio of the synchronous operation. The speed ratio of the synchronous operation is the ratio of the first moving speed to the second moving speed. The first moving speed is the moving speed of the ejector rod 54, and the second moving speed is the moving speed of the movable platform 34. In this embodiment, the speed ratio of the synchronous operation is defined as the ratio of the second moving speed to the first moving speed. That is, the speed ratio of the synchronous operation in this embodiment is the ratio (second moving speed / first moving speed) with the first moving speed as the denominator and the second moving speed as the numerator.

[0047] When the speed ratio of the synchronous action is less than "1", the forward speed of the ejector rod 54, which pushes the ejector pin 58 towards the mold closing direction DA, is faster than the backward speed of the movable platen 34, which moves towards the mold opening direction DB (refer to...). Figure 6 At this time, the position (absolute position) of the ejector pin 58 moves in the mold-closing direction DA. Therefore, a load is applied in the direction of pushing the molded article held by the holding device 18. That is, the smaller the speed ratio of the synchronous operation is, the greater the load acquired by the load acquisition unit 80 becomes in the direction corresponding to the mold-closing direction DA.

[0048] Conversely, when the speed ratio of the synchronized actions is greater than "1", the forward speed of the ejector rod 54 is slower than the backward speed of the movable platform 34 (see reference). Figure 7 At this time, the position (absolute position) of the ejector pin 58 moves in the mold opening direction DB. Therefore, a load is applied in the direction of stretching the molded article held by the holding device 18. That is, the greater the speed ratio of the synchronous operation is than "1", the greater the load acquired by the load acquisition unit 80 becomes in the direction corresponding to the mold opening direction DB.

[0049] The adjustment unit 82 adjusts the speed ratio of the second moving speed to the first moving speed such that the magnitude of the load acquired by the load acquisition unit 80 during synchronous operation is within a predetermined range. The upper limit of the predetermined range represents the upper limit of the load in the direction corresponding to the mold opening direction DB. Hereinafter, the direction corresponding to the mold opening direction DB is considered the positive direction. The lower limit of the predetermined range represents the lower limit of the load in the direction corresponding to the mold closing direction DA. Hereinafter, the direction corresponding to the mold closing direction DA is considered the negative direction.

[0050] If the magnitude of the load acquired by the load acquisition unit 80 during synchronous operation is less than the lower limit of a predetermined range, the direction of the load acquired by the load acquisition unit 80 is negative, and the absolute value of the load is greater than the lower limit. In this case, the adjustment unit 82 increases the speed ratio of the second moving speed to the first moving speed. This suppresses the load acting in the direction of the extruded molded article (the mold closing direction DA).

[0051] Conversely, if the magnitude of the load acquired by the load acquisition unit 80 during synchronous operation is greater than the upper limit of a predetermined range, the direction of the load acquired by the load acquisition unit 80 is indicated as the positive direction, and the absolute value of the load is indicated as a value greater than the upper limit. In this case, the adjustment unit 82 reduces the speed ratio of the second moving speed to the first moving speed. This suppresses the load acting in the direction of the stretched molded article (mold opening direction DB).

[0052] The setting change unit 84 changes the setting of at least one of the first drive source and the second drive source to achieve the speed ratio adjusted by the adjustment unit 82. In this embodiment, when the setting of the first drive source is changed, the setting change unit 84 changes the setting speed set in the first motor control unit 64 of the control pin drive motor 68 (the first drive source). In this embodiment, when the setting of the second drive source is changed, the setting change unit 84 changes the setting speed set in the second motor control unit 66 of the control mold drive motor 70 (the second drive source).

[0053] For example, the setting change unit 84 calculates at least one of a first target speed and a second target speed. If the first target speed is calculated to have a speed ratio adjusted by the adjustment unit 82, the setting change unit 84 outputs a command to the first motor control unit 64 to set the first target speed as the first moving speed. If the second target speed is calculated, the setting change unit 84 outputs a command to the second motor control unit 66 to set the second target speed as the second moving speed.

[0054] Next, the operation method of the arithmetic device 72 of the first embodiment will be described. Figure 8 This is a flowchart illustrating the computational processing flow of the arithmetic unit 72. The computational processing of the arithmetic unit 72 can be performed in each repeated cycle of the injection molding machine 12, from the first cycle to a specified cycle, or only in one or two or more specified cycles. Figure 8 The flowchart shows the computational processing performed in one cycle.

[0055] The computational processing of the computing device 72 begins after the molded article attached to the cavity surface 61 of the movable mold 30 is held by the holding device 18, which is arranged between the fixed mold 28 and the movable mold 30.

[0056] In step S1, the setting change unit 84 sets the first drive source and the second drive source to be the same as the first moving speed of the ejector rod 54 and the second moving speed of the movable platform 34. In this embodiment, the setting change unit 84 sets the setting speed set in the first motor control unit 64 of the control pin drive motor 68 (first drive source) and the setting speed set in the second motor control unit 66 of the control mold drive motor 70 (second drive source) to be the same. When the first moving speed and the second moving speed are set to be the same, the calculation process proceeds to step S2. Alternatively, the first moving speed and the second moving speed can be set to be different.

[0057] In step S2, the load acquisition unit 80 begins to acquire the load borne by the molded article held by the holding device 18. When load acquisition begins, the calculation process proceeds to step S3.

[0058] In step S3, the adjustment unit 82 compares the load acquired in step S2 with the lower limit of a predetermined range. Here, if the load acquired by the load acquisition unit 80 during synchronous operation is less than the lower limit of the predetermined range (step S3: Yes), the calculation process proceeds to step S4. Conversely, if the load acquired by the load acquisition unit 80 during synchronous operation is greater than the lower limit of the predetermined range (step S3: No), the calculation process proceeds to step S5.

[0059] In step S4, the adjustment unit 82 increases the speed ratio of the second moving speed to the first moving speed. The setting change unit 84 changes at least one of the first drive source and the second drive source to achieve the speed ratio adjusted by the adjustment unit 82. If at least one of the first drive source and the second drive source is changed, the calculation process proceeds to step S7.

[0060] In step S5, the adjustment unit 82 compares the load acquired in step S2 with the upper limit of a predetermined range. Here, if the load acquired by the load acquisition unit 80 during synchronous operation is greater than the upper limit of the predetermined range (step S5: Yes), the calculation process proceeds to step S6. Conversely, if the load acquired by the load acquisition unit 80 during synchronous operation is less than the upper limit of the predetermined range (step S5: No), the calculation process proceeds to step S7.

[0061] In step S6, the adjustment unit 82 decreases the speed ratio of the second moving speed to the first moving speed. The setting change unit 84 changes at least one of the first drive source and the second drive source to achieve the speed ratio adjusted by the adjustment unit 82. If at least one of the first drive source and the second drive source is changed, the calculation process proceeds to step S7.

[0062] In step S7, the arithmetic unit 72 determines whether the synchronization operation has ended. If the synchronization operation has not ended, the arithmetic process returns to step S3. Conversely, if the synchronization operation has ended, the arithmetic process ends.

[0063] As explained above, the arithmetic unit 72 adjusts the speed ratio of the second moving speed to the first moving speed in such a way that the load borne by the holding device 18 on the molded article is within a specified range during synchronous operation. Therefore, even if the relative position of the ejector pin 58 and the molded article changes during synchronous operation, excessive load on the holding device 18 holding the molded article can be suppressed. Furthermore, excessive load on the holding device 18 holding the molded article can be suppressed without the operator needing to confirm the relative position of the ejector pin 58 and the molded article.

[0064] Furthermore, when the speed ratio of the second moving speed to the first moving speed is extremely small, the idle travel range of the ejector pin 58 before the ejector rod 54 contacts the ejector plate 56 can be reduced.

[0065] In this embodiment, the arithmetic unit 72 changes the setting of at least one of the first drive source and the second drive source to achieve the speed ratio adjusted by the adjustment unit 82. Therefore, excessive load can be suppressed on the gripping device 18 that holds the molded product without requiring the operator to perform setting changes.

[0066] [Variation Example] The above-described embodiments can also be modified as follows.

[0067] (Variation Example 1) The speed ratio of synchronized actions can be defined as the ratio of the first moving speed to the second moving speed. That is, the speed ratio of synchronized actions in this variation is the ratio of the second moving speed as the denominator and the first moving speed as the numerator (first moving speed / second moving speed).

[0068] In this modified example, when the load acquired by the load acquisition unit 80 during synchronous operation is less than the lower limit of a predetermined range, the adjustment unit 82 decreases the speed ratio of the first moving speed to the second moving speed. This suppresses the load acting in the direction of the extruded molded article (drill-closing direction DA). Conversely, when the load acquired by the load acquisition unit 80 during synchronous operation is greater than the upper limit of a predetermined range, the adjustment unit 82 increases the speed ratio of the first moving speed to the second moving speed. This suppresses the load acting in the direction of the drawn molded article (drill-opening direction DB).

[0069] Therefore, similar to the implementation method, even if the relative position of the ejector pin 58 and the molded article changes during synchronous operation, it is possible to suppress the excessive load on the holding device 18 that holds the molded article.

[0070] (Variation Example 2) The adjustment unit 82 can also change the speed ratio of the synchronous action per unit time. For example, the longer the elapsed time since the start of the synchronous action, the more the adjustment unit 82 reduces the speed ratio of the synchronous action. As a specific example, the adjustment unit 82 reduces the speed ratio of the synchronous action in the order of "0.7", "0.5", and "0.3" as the cycle progresses. Alternatively, the adjustment unit 82 reduces the speed ratio of the synchronous action in the order of "0.7", "0.5", and "0.3" each time a unit time elapses in a cycle.

[0071] In this way, the adjustment unit 82 can change the speed ratio of the synchronous action per unit time. Therefore, compared with the case where the speed ratio is constant, the speed ratio of the synchronous action can be dynamically adjusted.

[0072] (Variation Example 3) Figure 9 This is a block diagram showing the arithmetic device 72 in Modified Example 3. Figure 9 In this variation, components that are identical to those described in the embodiments are marked with the same symbols. Furthermore, in this variation, descriptions that are repeated in the embodiments are omitted.

[0073] The arithmetic unit 72 in this modified example also includes a modification unit 92. The modification unit 92 changes the upper or lower limit value of a predetermined range used in the adjustment unit 82 according to user operation. An operation unit 94 is connected to this modification unit 92.

[0074] The operation unit 94 outputs the value input according to the user's operation to the modification unit 92. Specific examples of the operation unit 94 include a mouse and keyboard. The operation unit 94 may be composed of a touch panel or the like mounted on a display screen. When an upper limit value is input from the operation unit 94 according to the user's operation, the modification unit 92 changes the upper limit value of the currently set range in the adjustment unit 82 to the upper limit value input according to the user's operation. Conversely, when a lower limit value is input from the operation unit 94 according to the user's operation, the modification unit 92 changes the lower limit value of the currently set range in the adjustment unit 82 to the lower limit value input according to the user's operation.

[0075] In this way, the modification unit 92 can change the upper or lower limit of the specified range used in the adjustment unit 82 according to the user's operation. As a result, the allowable load of the holding device 18 can be adjusted according to the type of injection molding machine 12, mold 16, take-out device 14, etc.

[0076] (Variation Example 4) It can also replace the mold opening action to perform the pulling action. That is, in this modified example, a synchronous action is performed to synchronize the pulling action and the protruding action. The pulling action is the action of pulling the molded article held by the holding device 18 towards the mold closing direction DA. In this modified example, the second moving speed is the moving speed of the holding device 18.

[0077] Figure 10 This is a block diagram showing the configuration of a portion of the injection molding machine 12 in modified example 4. Figure 10 In this variation, components that are equivalent to those described in the embodiments are marked with the same symbols. Furthermore, in this variation, descriptions that are repeated in the embodiments are omitted.

[0078] In this modified example, the control device 26 has a third motor control unit 67 instead of the second motor control unit 66. The third motor control unit 67 controls the gripping drive motor 71 installed in the extraction device 14 to cause the extraction device 14 to perform a pulling action. The gripping drive motor 71 is a third drive source for driving the gripping device 18 in the mold-closing direction DA. The gripping device 18 moves in the mold-closing direction DA due to the motor driving force generated by the gripping drive motor 71. That is, the third motor control unit 67 controls the gripping drive motor 71 to move the gripping device 18 in the mold-closing direction DA. Furthermore, the third drive source... Figure 10 The component in question is a motor (71 for control and drive), but it can also be a compressor. The compressor can be a hydraulic compressor or a pneumatic compressor.

[0079] In this modified example, the setting change unit 841 changes the setting of at least one of the first drive source and the third drive source to achieve the speed ratio adjusted by the adjustment unit 82. When the setting of the third drive source is changed, in this modified example, the setting change unit 841 changes the setting speed set in the third motor control unit 67 that controls the control drive motor 71 (the third drive source).

[0080] Therefore, even if a synchronous action is performed that synchronizes the pulling and protruding actions, the same effect as the implementation method can be obtained.

[0081] (Variation Example 5) Figure 11 This is a block diagram representing the injection molding system 10 of variant example 5. Figure 11 In this variation, components that are identical to those described in the embodiments are marked with the same symbols. Furthermore, in this variation, descriptions that are repeated in the embodiments are omitted.

[0082] In the injection molding system 10 of this modified example, the injection molding machine 12 and the take-out device 14 are connected to a communication line 96. The communication line 96 can be wired or wireless. The control device 26 of the injection molding machine 12 and the control device 98 of the take-out device 14 send and receive various information to each other via the communication line 96.

[0083] In this modified example, the calculation device 72 is installed in the control device 98 of the extraction device 14 instead of the control device 26 installed in the injection molding machine 12.

[0084] The load acquisition unit 80 of the arithmetic device 72 (see reference) Figure 5 The load acquisition unit 80 receives a signal output from the load acquisition sensor 90 via the communication line 96. Based on this signal, the load acquisition unit 80 acquires the load borne by the holding device 18 holding the molded article during synchronous operation, similar to the embodiment.

[0085] Setting change unit 84 of arithmetic device 72 (see reference) Figure 5 The setting unit 84 calculates at least one of a first target speed and a second target speed to obtain the speed ratio adjusted by the adjustment unit 82. When calculating the first target speed, the setting change unit 84 outputs a command to the first motor control unit 64 via the communication line 96, stating that the first target speed should be set as the first moving speed. When calculating the second target speed, the setting change unit 84 outputs a command to the second motor control unit 66 via the communication line 96, stating that the second target speed should be set as the second moving speed. Thus, the setting change unit 84 can change at least one of the first moving speed set in the first motor control unit 64 and the second moving speed set in the second motor control unit 66 to obtain the speed ratio adjusted by the adjustment unit 82.

[0086] Therefore, even if the computing device 72 is provided in the extraction device 14, the same effect as in the embodiment can be obtained.

[0087] (Variation Example 6) Figure 12 This is a block diagram representing the injection molding system 10 of variant example 6. Figure 12 In this variation, the same symbols are used to denote components that are equivalent to those described in Variation 5. Furthermore, in this variation, descriptions that are repeated in the embodiment and Variation 5 are omitted.

[0088] The injection molding system 10 of this modified example also includes an external device 100, such as a personal computer, which is different from the injection molding machine 12 and the removal device 14. The external device 100 is connected to a communication line 96. The control device 102 of the external device 100 sends and receives various information with the control device 26 of the injection molding machine 12 and the control device 98 of the removal device 14 via the communication line 96.

[0089] In this modified example, even if the arithmetic unit 72 is located in the control device 102 of the external device 100, the arithmetic processing can be performed in the same way as in Modified Example 5, where the control device 98 of the extraction device 14 is located. Therefore, even if the arithmetic unit 72 is located in the external device 100, the same effect as in the implementation method can be obtained.

[0090] Additionally, the communication line 96 can also be connected to other injection molding machines and other ejection devices in an injection molding system different from injection molding system 10. The number of other injection molding machines and other ejection devices can be one or more. In this case, the control device 102 can manage the parameters used in injection molding machine 12 and one or more other injection molding machines. Furthermore, the arithmetic unit 72 included in the control device 102 can also adjust the speed ratio of the synchronous operation in injection molding machine 12 and the speed ratio of the synchronous operation in one or more other injection molding machines.

[0091] (Variation Example 7) The above-described implementation methods and variations can be combined arbitrarily without causing contradictions.

[0092] [invention] As inventions that can be grasped from the above embodiments and variations, the first invention and the second invention are described below.

[0093] (First Invention) The first invention is a calculation device (72) for calculating parameters used in an injection molding machine (12) that performs a synchronous action that synchronizes an opening action that opens the movable mold (30) in the mold opening direction (DB) or a pulling action that pulls the holding device 18 holding the molded article in the mold closing direction (DA) of the movable mold, and a protruding action that causes the ejector pin (58) to protrude from the movable mold. The calculation device (72) includes: a load acquisition unit (80) that acquires the load borne by the holding device from the molded article; and an adjustment unit (82) that adjusts the speed ratio between the first moving speed of the ejector rod (54) that drives the ejector pin in the mold closing direction and the second moving speed of the movable platen (34) or the holding device mounted on the movable mold, in such a way that the magnitude of the load acquired in the synchronous action is within a specified range. Therefore, even if the relative position of the ejector pin and the molded part changes during synchronous operation, it is possible to suppress the excessive load on the holding device that holds the molded part.

[0094] When the load is less than the lower limit of the range, the adjustment unit can increase the speed ratio of the second moving speed to the first moving speed, or decrease the speed ratio of the first moving speed to the second moving speed. This suppresses the load acting in the direction of the extruded molded article (the mold-closing direction).

[0095] When the load exceeds the upper limit of the range, the adjustment unit can decrease the speed ratio of the second moving speed to the first moving speed, or increase the speed ratio of the first moving speed to the second moving speed. This suppresses the load acting in the direction of the stretched molded article (mold opening direction).

[0096] The adjustment unit can also adjust the speed ratio for each cycle repeatedly executed by the injection molding machine. As a result, even if the relative position of the ejector pin and the molded part changes in a periodic unit, it is possible to suppress excessive load on the holding device that holds the molded part.

[0097] The arithmetic unit may also include at least one of the first drive source for driving the ejector rod, the second drive source for driving the movable platform, or the third drive source for driving the gripping device, to become a setting change unit (84) for the speed ratio adjusted by the adjustment unit. As a result, excessive load on the gripping device that holds the molded product can be suppressed without the operator having to perform setting change operations.

[0098] The arithmetic unit may also include a changing unit (92) that changes at least one of the upper or lower limits of the range according to user operation. This allows adjustment of the load that the control device can tolerate.

[0099] The adjustment unit can also change the speed ratio per unit time. Therefore, compared with the case where the speed ratio is constant, the speed ratio of synchronous action can be dynamically adjusted.

[0100] The calculation device can also be installed in the control device (26) of the injection molding machine. Therefore, even if there is no calculation device other than the injection molding machine, it is possible to suppress excessive load on the holding device holding the molded article when the relative position of the ejector pin and the molded article changes during synchronous operation.

[0101] The calculation device can also be installed in the control device (98) of the take-out device (14) with the holding device. Thus, even if the injection molding machine does not have a calculation device, it is possible to suppress excessive load on the holding device holding the molded article when the relative position of the ejector pin and the molded article changes during synchronous operation.

[0102] The calculation device can also be installed in the control device (102) of the external device (100) connected to the injection molding machine and the take-out device with the holding device. Thus, even if the injection molding machine and the take-out device do not have a calculation device, it is possible to suppress excessive load on the holding device holding the molded article when the relative position of the ejector pin and the molded article changes during synchronous operation.

[0103] (Second Invention) A second aspect of the present invention is an injection molding system (10) comprising the aforementioned calculation device, an injection molding machine, and an ejection device having a holding device. Because of the aforementioned calculation device, even if the relative position of the ejector pin and the molded article changes during synchronous operation, it is possible to suppress excessive load on the holding device holding the molded article. Symbol Explanation

[0104] 10: Injection molding system; 12: Injection molding machine 14: Removal device; 16: Mold 18: Holding device; 20: Mold closing device 22: Injection device; 24: Protrusion device 26, 98, 102: Control devices; 28: Fixed mold 30: Movable mold; 32: Fixed platform 34: Movable platform; 36: Backrest platform 38: Tie rod, 54: Push rod 56: Ejector plate, 58: Ejector pin 62: Motor control unit; 64: First motor control unit 66: Second motor control unit; 72: Computing unit 74: Information Processing Department; 76: Storage Department 80: Load Acquisition Department, 82: Adjustment Department 84: Setting and modification section; 100: External device.

Claims

1. A computing device (72) for calculating parameters used in an injection molding machine (12), The injection molding machine performs synchronous actions, which synchronize the mold opening action of opening the movable mold (30) in the mold opening direction (DB) or the pulling action of pulling the holding device (18) holding the molded article in the mold closing direction (DA) of the movable mold, and the ejection action of causing the ejector pin (58) to protrude from the movable mold. The arithmetic unit (72) is characterized by having: The load acquisition unit (80) acquires the load borne by the holding device from the molded article; and The adjustment unit (82) adjusts the speed ratio between the first moving speed of the ejector rod (54) that drives the ejector pin toward the mold closing direction and the second moving speed of the movable platform (34) for mounting the movable mold or the holding device, in such a way that the magnitude of the load obtained in the synchronous action is within a specified range.

2. The computing device according to claim 1, characterized in that, If the load is less than the lower limit of the specified range, the adjustment unit increases the speed ratio of the second moving speed to the first moving speed.

3. The computing device according to claim 1, characterized in that, When the load exceeds the upper limit of the specified range, the adjustment unit reduces the speed ratio of the second moving speed to the first moving speed.

4. The arithmetic device according to any one of claims 1 to 3, characterized in that, The adjustment unit adjusts the speed ratio for each molding cycle in which the injection molding machine repeatedly molds the article.

5. The arithmetic device according to any one of claims 1 to 3, characterized in that, The device includes a setting change unit (84) that changes at least one of the first drive source for driving the ejector rod, the second drive source for driving the movable platform, or the third drive source for driving the gripping device to achieve the speed ratio adjusted by the adjustment unit.

6. The arithmetic device according to any one of claims 1 to 3, characterized in that, It has a modification unit (92) that, according to user operation, changes at least one of the upper limit or lower limit of the specified range.

7. The arithmetic device according to any one of claims 1 to 3, characterized in that, The adjustment unit can change the speed ratio per unit time.

8. The arithmetic device according to any one of claims 1 to 3, characterized in that, The computing device is located in the control device (26) of the injection molding machine.

9. The arithmetic device according to any one of claims 1 to 3, characterized in that, The computing device is located in the control device (98) of the extraction device (14) having the holding device.

10. The arithmetic device according to any one of claims 1 to 3, characterized in that, The computing device is located in the control device (102) of the external device (100) connected to the injection molding machine and the take-out device having the holding device.

11. An injection molding system (10), characterized in that, have: The computing device, the injection molding machine, and the extraction device having the holding device, as described in any one of claims 1 to 3.

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