Injection molding machine and its control method

Abstract

To improve a performance of "multi-injection molding machine".SOLUTION: An injection molding machine includes: a central control part 200 that centrally controls injection molding operation; an injection device 2A that performs injection operation of a material based on first injection start signal output from the central control part 200; an injection device 2B that performs injection operation of the material based on second injection start signal output from the central control part 200; and a mold clamping device that performs mold clamping operation. Here, the injection molding machine is configured to adjust a time difference between a first injection start timing of the material from the injection device 2A and a second injection start timing of the material from the injection device 2B.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an injection molding machine and its control technology, and more particularly, to a technology effective when applied to an injection molding machine having a plurality of injection devices and its control technology.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2002-66712 (Patent Document 1) describes a technology related to an injection molding machine that uses a metal material typified by magnesium, a magnesium alloy, an aluminum alloy, or a zinc alloy.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An injection molding machine is a device that melts a material with heat and then pours it into a mold to produce a molded product, and is a device that can process a series of injection molding steps such as melting of the material, pouring (injection) into the mold, cooling, and removal.

[0005] In this regard, an injection molding machine is generally composed of, for example, an injection device and a mold clamping device. When manufacturing a large-sized molded product, the amount of molten material ejected from the injection device increases. This means that the diameter of the screw of the injection device increases, and the size of the heating device for melting the material also increases. However, there are limits to the increase in the screw diameter and the heating device size. Also, depending on the material, the molten material may solidify immediately after being ejected. When manufacturing a large-sized molded product, the molten material may solidify before reaching the entire mold, resulting in the inability to manufacture the molded product.

[0006] Therefore, in order to provide an injection molding machine that can handle the manufacture of large molded products and the use of materials that solidify quickly, an injection molding machine equipped with multiple injection devices for a single clamping device is being considered. In this case, the amount of molten material injected from all multiple injection devices can be increased without increasing the screw diameter or heating device size of each of the multiple injection devices, thus providing the advantage of easily manufacturing large molded products. Furthermore, since molten material is injected from multiple injection devices, even when using materials that solidify quickly after injection, it is thought that it is possible to suppress the solidification of the injected molten material before it spreads throughout the entire mold.

[0007] Therefore, from the viewpoint of providing an injection molding machine that can handle the manufacture of large molded products or the use of materials that solidify quickly, an injection molding machine equipped with multiple injection devices for a single clamping device (hereinafter sometimes referred to as a "multi-injection molding machine") is useful. However, as a result of the inventor's investigation, it has become clear that there is room for improvement specific to the "multi-injection molding machine". For this reason, ingenuity is desired to overcome the room for improvement present in the "multi-injection molding machine". [Means for solving the problem]

[0008] An injection molding machine in one embodiment includes a central control unit that provides overall control of the injection molding operation, a first injection device that performs a material injection operation based on a first injection start signal for the first injection device output from the central control unit, a second injection device that performs a material injection operation based on a second injection start signal for the second injection device output from the central control unit, and a mold clamping device that performs a mold clamping operation.

[0009] Here, the injection molding machine is configured to adjust the time difference between the start timing of the first injection of material from the first injection device and the start timing of the second injection of material from the second injection device.

[0010] In one embodiment, the control method for an injection molding machine includes a step of adjusting the time difference between the first injection start timing of the material from the first injection device, which performs the material injection operation based on a first injection start signal for the first injection device output from a central control unit that comprehensively controls the injection molding operation, and the second injection start timing of the material from the second injection device, which performs the material injection operation based on a second injection start signal for the second injection device output from the central control unit. [Effects of the Invention]

[0011] According to one embodiment, the performance of the "multi-injection molding machine" can be improved. [Brief explanation of the drawing]

[0012] [Figure 1] This is a plan view showing the schematic configuration of a "twin injection molding machine". [Figure 2] This is a partial cross-sectional view showing the schematic configuration of a "twin injection molding machine". [Figure 3] This diagram shows the configuration of a hydraulic control system, including the hydraulic equipment. [Figure 4] This is a functional block diagram showing the configuration of a distributed control system. [Figure 5] This is a functional block diagram showing the configuration of the distributed control system in embodiment 1. [Figure 6] This is a flowchart explaining the operation of Embodiment Mode 1. [Figure 7] This is a flowchart explaining the operation of manifestation mode 2. [Modes for carrying out the invention]

[0013] In all the drawings illustrating the embodiments, the same reference numeral is used for identical components, and repeated explanations of them are omitted. Hatching may be used even in plan views to improve clarity.

[0014] <Configuration of the "Twin Injection Molding Machine"> The technical idea in this embodiment can be widely applied to a "multi-injection molding machine" in which a plurality of injection devices are provided for one clamping device. In this regard, hereinafter, a "twin injection molding machine" in which two injection devices are provided for one clamping device among "multi-injection molding machines" will be taken as an example to explain the technical idea in this embodiment.

[0015] <<Overview of "Twin Injection Molding Device">> FIG. 1 is a plan view showing a schematic configuration of a "twin injection molding machine 100".

[0016] In FIG. 1, the "twin injection molding machine 100" has one clamping device 1, an injection device 2A, and an injection device 2B. Here, the clamping device 1 is a device that performs a clamping operation. For example, the clamping device 1 is configured to be able to mount a mold into which the material ejected from the injection device 2A and the material ejected from the injection device 2B are poured, and by performing a clamping operation on the mold, it is a device that manufactures a molded product by pouring the material into the cavity (sealed space) formed. On the other hand, the injection device 2A and the injection device 2B are devices that perform an injection operation. For example, they are devices that knead and melt the material and inject the kneaded and melted material into the cavity formed by the clamping device 1.

[0017] <<Configuration of Clamping Device>> FIG. 2 is a partial cross-sectional view showing a schematic configuration of the "twin injection molding machine 100".

[0018] Note that the "twin injection molding machine 100" has the injection device 2A and the injection device 2B as shown in FIG. 1. However, since the injection device 2A and the injection device 2B have the same configuration, in FIG. 2, only one injection device 2A will be illustrated and described.

[0019] The mold clamping device 1 has a movable platen 10 that can move and a fixed platen 11 that is fixed, and is configured to be able to variably control the distance between the movable platen 10 and the fixed platen 11. And between the movable platen 10 and the fixed platen 11, a movable mold (die) 12 and a fixed mold (die) 13 can be arranged. Thereby, for example, by variably controlling the distance between the movable platen 10 and the fixed platen 11 by the mold clamping device 1, the distance between the movable mold 12 and the fixed mold 13 can be reduced to "close the mold", and the distance between the movable mold 12 and the fixed mold 13 can be increased to "open the mold". At this time, when the mold is "closed" between the movable mold 12 and the fixed mold 13, a sealed space (cavity) CAV is formed between the movable mold 12 and the fixed mold 13, and a molded product is formed by pouring a material into this sealed space CAV. In particular, in the "twin injection molding machine 100" shown in FIG. 2, when the mold is "closed" between the movable mold 12 and the fixed mold 13, one sealed space CAV is formed, and a molded product is formed by pouring a material into this sealed space CAV. In this way, the mold clamping device 1 is configured.

[0020] <<Configuration of Injection Device>> Next, as shown in FIG. 2, an injection device 2A for extruding a material is connected to the mold clamping device 1, and the material extruded from the injection device 2A flows into the sealed space CAV formed by "closing the mold" between the movable mold 12 and the fixed mold 13.

[0021] This injection device 2 has a hopper 21A for containing a material (raw material) and a cylinder 22A. And when a material is put into the hopper 21A, this material is kneaded by a rotatable screw 23A arranged inside the cylinder 22A. Specifically, the screw 23A is connected to a screw rotation motor 24A, and is configured such that the screw 23A rotates by driving this screw rotation motor 24A.

[0022] At this time, a heater 25A is arranged around the cylinder 22A, and the material placed inside the cylinder 22A is heated by the heater 25A and kneaded by the screw 23A to become a molten material. A nozzle 26A is provided at the tip of the cylinder 22A. A piston 27A is connected to the screw 23A, and the forward and backward movement of this piston 27A is controlled by a hydraulic device 28A. For example, if the hydraulic device 28A is controlled to move the piston 27A forward, the screw 23A connected to the piston 27A moves forward, and as a result the molten material pushed out by the moving screw 23A is injected from the nozzle 26A. In this way, the injection device 2A is configured.

[0023] <<Operation of the "Twin Injection Molding Machine">> The "Twin Injection Molding Machine 100" is configured as described above, and its operation is briefly explained below. In Figure 2, when material is placed in the hopper 21A, this material is heated by the heater 25A and kneaded by the rotatable screw 23A located inside the cylinder 22A, resulting in a molten material. Subsequently, the hydraulic device 28A controls the piston 27A to move forward. This causes the screw 23A connected to the piston 27A to move forward, and the molten material pushed out by the moving screw 23A is injected from the nozzle 26A toward the clamping device 1. As a result, the material fills the sealed space CAV formed between the movable mold 12 and the fixed mold 13, and a molded product is formed.

[0024] Furthermore, in the "Twin Injection Molding Machine 100," the same injection operation as described above is performed not only in injection unit 2A but also in injection unit 2B. As a result, the "Twin Injection Molding Machine 100" offers the advantage of easily manufacturing large molded products because it is possible to increase the amount of molten material injected from the entire injection unit, combining injection unit 2A and injection unit 2B, without increasing the screw diameter or heating device size of each of the injection unit 2A and injection unit 2B. Moreover, because molten material is injected from both injection unit 2A and injection unit 2B, even when using materials that solidify immediately after injection, it is possible to suppress the solidification of the injected molten material before it can spread throughout the entire sealed space CAV.

[0025] <<Hydraulic System Configuration>> Next, we will explain the configuration of the hydraulic system 28A.

[0026] Figure 3 shows the configuration of the hydraulic control system, including the hydraulic device 28A.

[0027] In Figure 3, the hydraulic device 28A is configured to move the piston 27A connected to the screw 23A in the forward direction. In other words, the hydraulic device 28A is a device that uses hydraulic pressure to move the piston 27A, thereby advancing the screw 23A connected to the piston 27A, and injecting the molten material pushed out by the advancing screw 23A from the nozzle toward the clamping device.

[0028] A hydraulic system 28A having such functions includes an accumulator 501A for storing oil, a pump 502A for supplying oil to the accumulator 501A, a passage 503A for supplying oil from the accumulator 501A to move the piston 27A, a passage 504A for supplying oil pushed out by the piston 27A, and a servo valve 505A provided in the passage 503A. In this configuration, the hydraulic pressure for moving the piston 27A is adjusted by adjusting the opening degree of the servo valve 505A. In other words, by adjusting the opening degree of the servo valve 505A, the hydraulic pressure applied to the piston 27A is adjusted, causing the piston 27A to move forward.

[0029] Here, the injection speed when the molten material extruded by the screw 23A connected to the forward-moving piston 27A is injected from the nozzle toward the clamping device is determined by the flow rate of oil flowing from the accumulator 501A through the passage 503A to the piston 27A. The servo valve 505A plays a role in adjusting the flow rate of oil flowing through the passage 503A. In other words, by controlling the opening degree of the servo valve 505A, the flow rate of the oil is adjusted, and the injection speed is determined. For this reason, the opening degree of the servo valve 505A is controlled in order to control the injection speed.

[0030] The following describes the configuration for adjusting the opening degree of the servo valve 505A.

[0031] In Figure 3, the central control unit 200 has the function of comprehensively controlling the injection molding operation performed by the injection molding machine. For example, it is configured to output an injection start signal to the hydraulic control unit 300A when the injection operation is to begin.

[0032] The hydraulic control unit 300A is configured to receive the injection start signal output from the central control unit 200, and upon receiving the injection start signal output from the central control unit 200, it is configured to output a command signal to the servo amplifier 400A. Specifically, the command signal is a signal indicating a target value for the opening degree of the servo valve 505A.

[0033] The servo amplifier 400A is configured to receive command signals output from the hydraulic control unit 300A. Upon receiving the command signals from the hydraulic control unit 300A, it is configured to supply output (power) to the servo valve 505A to achieve the opening degree specified in the target value indicated in the command signals. The servo valve 505A is then configured to change its opening degree based on the power output from the servo amplifier 400A.

[0034] In this process, the opening degree of the servo valve 505A is detected, and this detection signal is fed back to the servo amplifier 400A. The servo amplifier 400A is then configured to compare the target value indicated by the command signal input from the hydraulic control unit 300A with the feedback detection signal, and to perform feedback control so that the difference approaches zero.

[0035] <<Operation of the hydraulic system>> Next, the operation of the hydraulic control system, including the hydraulic device 28A, will be described.

[0036] In Figure 3, when the central control unit 200, which comprehensively controls the injection molding operation performed by the injection molding machine, determines that it is time to start the injection operation, the central control unit 200 outputs an injection start signal to the hydraulic control unit 300A. Then, when the hydraulic control unit 300A receives the injection start signal output from the central control unit 200, it outputs a command signal to the servo amplifier 400A.

[0037] Next, when the servo amplifier 400A receives a command signal output from the hydraulic control unit 300A, it supplies output (power) to the servo valve 505A to achieve the opening degree specified in the command signal. As a result, the opening degree of the servo valve 505A changes based on the power output from the servo amplifier 400A.

[0038] In this hydraulic control system, the opening degree of the servo valve 505A is detected, and this detection signal is fed back to the servo amplifier 400A. The servo amplifier 400A then compares the target value indicated by the command signal input from the hydraulic control unit 300A with the feedback detection signal and performs feedback control so that the difference approaches zero.

[0039] As described above, the servo valve 505A is controlled so that its opening degree matches the target value indicated by the command signal output from the hydraulic control unit 300A.

[0040] In this way, the opening of the servo valve 505A is controlled, which adjusts the flow rate of the oil and controls the hydraulic pressure required to move the piston 27A. For example, by controlling the opening of the servo valve 505A and increasing the hydraulic pressure applied to the piston 27A, the piston 27A moves forward. As a result, the screw 23A connected to the piston 27A moves forward, and the moving screw 23A injects the molten material from the nozzle towards the clamping device. The hydraulic control system operates in this manner.

[0041] <Distributed control system> The "twin injection molding machine 100" having the configuration described above employs a distributed control system, and this distributed control system will be explained below.

[0042] Figure 4 is a functional block diagram showing the configuration of a distributed control system.

[0043] In Figure 4, the distributed control system includes a central control unit 200, an injection unit 2A, and an injection unit 2B. The central control unit 200 and the injection unit 2A are connected by communication, and the central control unit 200 and the injection unit 2B are also connected by communication.

[0044] The injection device 2A includes the hydraulic control unit 300A, the servo amplifier 400A, and the servo valve 505A described above. Similarly, the injection device 2B includes the hydraulic control unit 300B, the servo amplifier 400B, and the servo valve 505B.

[0045] In the "twin injection molding machine 100" consisting of a distributed control system configured in this way, the central control unit 200 controls injection devices 2A and 2B respectively via communication. Specifically, the "first injection start signal" output from the central control unit 200 is input to the hydraulic control unit 300A of injection device 2A via communication. The hydraulic control unit 300A, having received the "first injection start signal," then outputs a "first command signal" to the servo amplifier 400A. Subsequently, the "first command signal" output from the hydraulic control unit 300A is input to the servo amplifier 400A. The servo amplifier 400A then supplies output to the servo valve 505A to achieve the opening degree according to the target value indicated in the "first command signal." As a result, the opening degree of the servo valve 505A changes based on the power output from the servo amplifier 400A.

[0046] Next, referring to Figure 3, as a result of the change in the opening of the servo valve 505A, the flow rate of the oil is adjusted, and the hydraulic pressure for moving the piston 27A is controlled. In other words, for example, when the opening of the servo valve 505A is controlled, the hydraulic pressure applied to the piston 27A is increased, causing the piston 27A to move forward. As a result, the screw 23A connected to the piston 27A moves forward, and the molten material is injected from the nozzle toward the clamping device by the moving screw 23A. In this way, the injection device 2A operates.

[0047] Similarly, the "second injection start signal" output from the central control unit 200 is also input to the hydraulic control unit 300B of the injection device 2B via communication. The hydraulic control unit 300B, having received the "second injection start signal," then outputs a "second command signal" to the servo amplifier 400B. Subsequently, the "second command signal" output from the hydraulic control unit 300B is input to the servo amplifier 400B. The servo amplifier 400B then supplies output to the servo valve 505B to achieve the opening degree according to the target value indicated in the "second command signal." As a result, the opening degree of the servo valve 505B changes based on the power output from the servo amplifier 400A.

[0048] Next, referring to Figure 3, as a result of the change in the opening of the servo valve 505B, the flow rate of the oil is adjusted, and the hydraulic pressure required to move the piston 27B is controlled. In other words, for example, when the opening of the servo valve 505B is controlled, the hydraulic pressure applied to the piston 27B is increased, causing the piston 27B to move forward. As a result, the screw 23B connected to the piston 27B moves forward, and the molten material is injected from the nozzle toward the clamping device by the moving screw 23B. In this way, the injection device 2B operates.

[0049] In such a distributed control system, the control board constituting the hydraulic control unit 300A (sometimes referred to as the "first control board") and the control board constituting the hydraulic control unit 300B (sometimes referred to as the "second control board") are separate components. This is for the reasons shown below.

[0050] In other words, each of the injection devices 2A and 2B is equipped with various devices such as limit switches, sensors, and valves, but in order to reduce the wiring length between these devices and the control board, the "first control board" and the "second control board" are separate components.

[0051] Specifically, in the "Twin Injection Molding Machine 100," various components are located throughout the machine. If all the wiring connecting these components were connected to a single control board, the wiring length would become very long. In contrast, if the control boards are distributed and located on the clamping device side, for example, the components located on the clamping device side can be connected to that control board. This allows for a reduction in wiring length.

[0052] For these reasons, instead of controlling both injection units 2A and 2B with a single control board, a distributed control system is employed in which separate control boards are provided for each injection unit 2A and 2B, allowing for independent control of injection units 2A and 2B. This distributed control system has the advantage of shortening the length of wiring connecting the equipment and the control boards.

[0053] However, the inventors' investigations revealed that when configuring the "twin injection molding machine 100" using a distributed control system having the advantages described above, there is room for improvement specific to the distributed control system. In other words, the inventors have newly discovered that when configuring the "twin injection molding machine 100" using a distributed control system, there is room for improvement specific to the distributed control system, and this room for improvement will be explained below.

[0054] <Room for improvement> For example, as shown in Figure 4, in a distributed control system, the "first injection start signal" output from the central control unit 200 is transmitted via communication to the hydraulic control unit 300A of the injection device 2A, and the "second injection start signal" output from the central control unit 200 is also transmitted via communication to the hydraulic control unit 300B of the injection device 2B. Here, the "first distance" between the central control unit 200 and the hydraulic control unit 300A of the injection device 2A is different from the "second distance" between the central control unit 200 and the hydraulic control unit 300B of the injection device 2B. As a result, the time at which the "first injection start signal" reaches the hydraulic control unit 300A of the injection device 2A is different from the time at which the "second injection start signal" reaches the hydraulic control unit 300B of the injection device 2B. This means that the injection start timing in injection device 2A and the injection start timing in injection device 2B are out of sync. This can lead to uneven material filling in the sealed cavity of the mold clamping device, where the material is injected. Uneven material filling can prevent the production of properly molded products.

[0055] Thus, in the "twin injection molding machine 100" employing a distributed control system, there is room for improvement due to the following factors: (1) the "first control board" constituting the hydraulic control unit 300A of injection unit 2A and the "second control board" constituting the hydraulic control unit 300B of injection unit 2B are separate components, and (2) the central control unit 200 is connected to injection unit 2A and injection unit 2B via communication. As a result, the injection start timing in injection unit 2A and the injection start timing in injection unit 2B may unintentionally be out of sync, potentially leading to uneven material filling in the sealed space of the mold clamping device.

[0056] In particular, in the "twin injection molding machine 100" which uses magnesium alloy as a material, the injection time is short, only a few tens of milliseconds. If the injection start timing in injection device 2A and the injection start timing in injection device 2B are unintentionally out of sync by a few milliseconds, an area for improvement becomes apparent: uneven material filling occurs in the sealed space of the clamping device.

[0057] Therefore, in this embodiment, we have made efforts to overcome the areas for improvement specific to the "twin injection molding machine 100" employing the distributed control system described above. The technical concept of this embodiment, which incorporates these efforts, will be explained below.

[0058] <Basic Concept in the Embodiment> The basic concept in this embodiment is to implement measures to prevent the manifestation of an "unintended discrepancy" between the first injection start timing of the molten material from the first injection device and the second injection start timing of the molten material from the second injection device. According to this basic concept, it is possible to suppress an "unintended discrepancy" between the first injection start timing in the first injection device and the second injection start timing in the second injection device. As a result, according to this basic concept, it is possible to suppress unevenness in the material filling state in the sealed space of the mold clamping device.

[0059] Specifically, the measure to prevent "unintended discrepancies" from becoming apparent is to intentionally adjust the time difference between the start timing of the first injection of molten material from the first injection device and the start timing of the second injection of molten material from the second injection device, so that "unintended discrepancies" do not become apparent.

[0060] This design makes it possible to suppress unevenness in the material filling within the sealed space of the mold clamping device. This is because intentionally adjusting the time difference between the first injection start timing in the first injection device and the second injection start timing in the second injection device means that it becomes possible to adjust the time difference between the first injection start timing in the first injection device and the second injection start timing in the second injection device in order to suppress unevenness in the material filling within the sealed space of the mold clamping device.

[0061] In other words, the basic idea is that if the aforementioned "unintended deviation" occurs, and this "unintended deviation" causes an uneven distribution of material in the sealed space of the clamping device, then the idea is to suppress the uneven distribution of material in the sealed space of the clamping device by intentionally adjusting the timing in a way that prevents the "unintended deviation" from becoming apparent.

[0062] To embody this fundamental idea, there are two manifestations, for example, manifestation mode 1 and manifestation mode 2, as shown below. Each manifestation mode will be explained below.

[0063] <Manifestation Mode 1 (Synchronization)> Embodiment 1, which embodies the basic concept, is an embodiment in which the start timing of the first injection of material from the first injection device and the start timing of the second injection of material from the second injection device are synchronized.

[0064] In other words, in embodiment 1, the basic idea (ingredient) of intentionally adjusting the time difference between the first injection start timing of the molten material from the first injection device and the second injection start timing of the molten material from the second injection device, so that the aforementioned "unintended discrepancy" does not become apparent, is embodied in a configuration that synchronizes the first injection start timing and the second injection start timing. That is, in embodiment 1, the basic idea is embodied in a configuration that adjusts the time difference between the first injection start timing and the second injection start timing to zero.

[0065] <<Configuration of the Distributed Control System>> Figure 5 is a functional block diagram showing the configuration of the distributed control system in embodiment 1.

[0066] In Figure 5, the distributed control system in embodiment 1 includes a central control unit 200, a synchronization signal generation unit 600, and injection devices 2A and 2B. The central control unit 200 and the synchronization signal generation unit 600 are connected by communication. The central control unit 200 and injection device 2A are also connected by communication, as are the central control unit 200 and injection device 2B. Specifically, the central control unit 200 is configured to output a "first injection start signal" for injection device 2A to injection device 2A, and this "first injection start signal" is output to injection device 2A via communication. Similarly, the central control unit 200 is configured to output a "second injection start signal" for injection device 2B to injection device 2B, and this "second injection start signal" is output to injection device 2A via communication. Furthermore, the central control unit 200 is configured to output a "synchronous signal generation command" to the synchronous signal generation unit 600, and the "synchronous signal generation command" is output to the synchronous signal generation unit 600 via communication.

[0067] The synchronization signal generation unit 600 is configured to generate a "synchronization signal" when it receives a "synchronization signal generation command" output from the central control unit 200. The synchronization signal generation unit 600 is configured to simultaneously output the generated "synchronization signal" to injection devices 2A and 2B, respectively. Here, injection device 2A has a hydraulic control unit 300A, a servo amplifier 400A, and a servo valve 505A. Similarly, injection device 2B has a hydraulic control unit 300B, a servo amplifier 400B, and a servo valve 505B.

[0068] The hydraulic control unit 300A is configured to include a first predetermined time measurement unit 700A and a first command signal output unit 800A, and is configured to receive a "synchronization signal" generated by the synchronization signal generation unit 600. When the "synchronization signal" is input to the hydraulic control unit 300A, the first predetermined time measurement unit 700A is configured to start measuring a preset first predetermined time, for example, by using a timer. The first command signal output unit 800A is configured to output a "first command signal" to the servo amplifier 400A when the measurement of the first predetermined time by the first predetermined time measurement unit 700A is completed.

[0069] Similarly, the hydraulic control unit 300B is configured to include a second predetermined time measurement unit 700B and a second command signal output unit 800B, and is configured to receive a "synchronization signal" generated by the synchronization signal generation unit 600. When the "synchronization signal" is input to the hydraulic control unit 300B, the second predetermined time measurement unit 700B is configured to start measuring a preset second predetermined time, for example, by using a timer. The second command signal output unit 800A is configured to output a "second command signal" to the servo amplifier 400B when the measurement of the second predetermined time by the second predetermined time measurement unit 700B is completed.

[0070] In other words, in the distributed control system in embodiment 1, the hydraulic control unit 300A is not configured to output a "first command signal" to the servo amplifier 400A simply by receiving the "first injection start signal" output from the central control unit 200. Rather, it is configured to output a "first command signal" to the servo amplifier 400A only after receiving the "synchronization signal" generated by the synchronization signal generation unit 600 and after a first predetermined time has elapsed.

[0071] Similarly, the hydraulic control unit 300B is not configured to output a "second command signal" to the servo amplifier 400B simply by receiving the "second injection start signal" output from the central control unit 200. Rather, it is configured to output a "second command signal" to the servo amplifier 400B only after receiving the "synchronization signal" generated by the synchronization signal generation unit 600 and after a second predetermined time has elapsed.

[0072] <<Operation of the Distributed Control System>> Figure 6 is a flowchart illustrating the operation of the distributed control system in embodiment 1, and the operation of this distributed control system will be explained using Figures 5 and 6.

[0073] First, the central control unit 200 outputs a "first injection start signal" to the hydraulic control unit 300A of the injection device 2A via communication, and also outputs a "second injection start signal" to the hydraulic control unit 300B of the injection device 2B (S101). The "first injection start signal" output from the central control unit 200 is input to the hydraulic control unit 300A of the injection device 2A, while the "second injection start signal" output from the central control unit 200 is input to the hydraulic control unit 300B of the injection device 2B.

[0074] Here, even when the hydraulic control unit 300A receives the "first injection start signal," it remains in a waiting state without immediately outputting the "first command signal" to the servo amplifier 400A. Similarly, even when the hydraulic control unit 300B receives the "second injection start signal," it remains in a waiting state without immediately outputting the "second command signal" to the servo amplifier 400B.

[0075] Furthermore, the central control unit 200 outputs a "synchronization signal generation command" to the synchronization signal generation unit 600 via communication (S102). The synchronization signal generation unit 600 then generates a "synchronization signal" based on the "synchronization signal generation command" output from the central control unit 200 (S103). Subsequently, the "synchronization signal" generated by the synchronization signal generation unit 600 is input to the hydraulic control unit 300A and the hydraulic control unit 300B, respectively (S104A, S104B).

[0076] When a "synchronization signal" is input to the hydraulic control unit 300A, the first predetermined time measurement unit 700A starts measuring a predetermined time X (here, the first predetermined time = the second predetermined time = predetermined time X) (S105A). Then, when the measurement of the predetermined time X by the first predetermined time measurement unit 700A is completed, the first command signal output unit 800A outputs a "first command signal" to the servo amplifier 400A (S106A).

[0077] Similarly, when a "synchronization signal" is input to the hydraulic control unit 300B, the second predetermined time measurement unit 700B starts measuring a predetermined time X that has been set in advance (S105B). Then, when the measurement of the predetermined time X by the second predetermined time measurement unit 700B is completed, the second command signal output unit 800B outputs a "second command signal" to the servo amplifier 400A (S106B).

[0078] Thus, the hydraulic control unit 300A simply waits even after receiving the "first injection start signal" output from the central control unit 200, and does not output the "first command signal" to the servo amplifier 400A. Furthermore, after receiving the "synchronization signal" generated by the synchronization signal generation unit 600, the "first command signal" is output to the servo amplifier 400A only after a predetermined time X has elapsed.

[0079] Similarly, even when the hydraulic control unit 300B receives the "second injection start signal" output from the central control unit 200, it simply remains in a waiting state and does not output the "second command signal" to the servo amplifier 400B. Furthermore, after receiving the "synchronization signal" generated by the synchronization signal generation unit 600 and after a predetermined time X has elapsed, the "second command signal" is output to the servo amplifier 400B.

[0080] This initiates the injection operation in injection devices 2A and 2B.

[0081] Specifically, the "first command signal" output from the first command signal output unit 800A of the hydraulic control unit 300A is input to the servo amplifier 400A. The servo amplifier 400A then supplies output to the servo valve 505A to achieve the opening degree according to the target value indicated in the "first command signal" (S107A). As a result, the opening degree of the servo valve 505A changes based on the power output from the servo amplifier 400A.

[0082] Subsequently, the opening of the servo valve 505A changes, which adjusts the flow rate of the oil and controls the hydraulic pressure required to move the piston 27A. In other words, for example, by controlling the opening of the servo valve 505A and increasing the hydraulic pressure applied to the piston 27A, the piston 27A moves forward. As a result, the screw 23A connected to the piston 27A moves forward, and the moving screw 23A injects the molten material from the nozzle towards the clamping device (see Figure 3). In this way, the injection device 2A operates (S108A).

[0083] Similarly, the "second command signal" output from the second command signal output unit 800B of the hydraulic control unit 300B is input to the servo amplifier 400B. The servo amplifier 400B then supplies output to the servo valve 505B to achieve the opening degree indicated in the target value shown in the "second command signal" (S107B). As a result, the opening degree of the servo valve 505B changes based on the power output from the servo amplifier 400B.

[0084] Subsequently, the opening of the servo valve 505B changes, which adjusts the flow rate of the oil and controls the hydraulic pressure required to move the piston 27B. In other words, for example, by controlling the opening of the servo valve 505B and increasing the hydraulic pressure applied to the piston 27B, the piston 27B moves forward. As a result, the screw 23B connected to the piston 27B moves forward, and the molten material is injected from the nozzle toward the clamping device by the moving screw 23B (see Figure 3). In this way, the injection device 2B operates (S108B).

[0085] <<Characteristics of Embodiment 1>> Next, we will explain the characteristics of Embodiment Mode 1.

[0086] A key feature of Embodiment 1 is that, as shown in Figure 5, for example, a synchronization signal generation unit 600 is provided that generates a "synchronization signal" based on a "synchronization signal generation command" output from the central control unit 200, and by outputting the "synchronization signal" from this synchronization signal generation unit 600 to the hydraulic control unit 300A and the hydraulic control unit 300B, the timing of the output of the "first command signal" from the hydraulic control unit 300A to the servo amplifier 400A is synchronized with the timing of the output of the "second command signal" from the hydraulic control unit 300B to the servo amplifier 400B. In other words, a key feature of Embodiment 1 is that by using the "synchronization signal" generated by the synchronization signal generation unit 600, the timing of the output of the "first command signal" from the hydraulic control unit 300A to the servo amplifier 400A is synchronized with the timing of the output of the "second command signal" from the hydraulic control unit 300B to the servo amplifier 400B.

[0087] Specifically, the hydraulic control unit 300A simply waits even after receiving the "first injection start signal" output from the central control unit 200. After receiving the "synchronization signal" generated by the synchronization signal generation unit 600, and only after a predetermined time X has elapsed, does it output the "first command signal" to the servo amplifier 400A. Similarly, the hydraulic control unit 300B also simply waits even after receiving the "second injection start signal" output from the central control unit 200. After receiving the "synchronization signal" generated by the synchronization signal generation unit 600, and only after a predetermined time X has elapsed, does it output the "second command signal" to the servo amplifier 400B.

[0088] As a result, according to embodiment 1, it is possible to suppress "unintended discrepancies" between the first injection start timing in injection device 2A and the injection start timing in the second injection device. As a result, according to embodiment 1, it is possible to suppress unevenness in the material filling state in the sealed space of the mold clamping device caused by "unintended discrepancies" between the first injection start timing in injection device 2A and the second injection start timing in injection device 2B.

[0089] For example, in Figure 4, which illustrates "<Room for Improvement>", there is a time difference of about 5 ms between the "injection start signal" input to the hydraulic control unit 300A and the "injection start signal" input to the hydraulic control unit 300B. As a result, when the injection time is short, such as in the "twin injection molding machine 100" which uses magnesium alloy as the material, the first injection start timing in injection device 2A and the second injection start timing in injection device 2B will unintentionally be out of sync by about 5 ms, resulting in uneven material filling in the sealed space of the clamping device.

[0090] In contrast, according to the embodiment 1 shown in Figure 5, the timing of outputting the "first command signal" from the hydraulic control unit 300A to the servo amplifier 400A and the timing of outputting the "second command signal" from the hydraulic control unit 300B to the servo amplifier 400B are synchronized by using the "synchronization signal" generated by the synchronization signal generation unit 600.

[0091] As a result, the time difference between the "first command signal" output from the hydraulic control unit 300A and the "second command signal" output from the hydraulic control unit 300B can be kept to a deviation (variation) of 200 μs or less. This means that the difference between the first injection start timing in injection device 2A and the second injection start timing in injection device 2B can be reduced to about 200 μs. As a result, according to embodiment 1, even when the injection time is short, such as in the "twin injection molding machine 100" which uses magnesium alloy as the material, it is possible to suppress unevenness in the material filling state in the sealed space of the clamping device.

[0092] In the embodiment 1, the timing at which the hydraulic control unit 300A outputs the "first command signal" to the servo amplifier 400A and the timing at which the hydraulic control unit 300B outputs the "second command signal" to the servo amplifier 400B can be synchronized by outputting a "synchronization signal" from the synchronization signal generation unit 600 to the hydraulic control unit 300A and the hydraulic control unit 300B, respectively, is largely due to the following factors.

[0093] (Factor 1) The hydraulic control unit 300A remains in standby mode even when it receives the "first injection start signal" output from the central control unit 200. Similarly, the hydraulic control unit 300B remains in standby mode even when it receives the "second injection start signal" output from the central control unit 200.

[0094] For example, the "first injection start signal" and the "second injection start signal" are output from the central control unit 200 to the hydraulic control unit 300A and the hydraulic control unit 300B via communication, respectively. As a result, the first distance between the central control unit 200 and the hydraulic control unit 300A is different from the second distance between the central control unit 200 and the hydraulic control unit 300B. This causes an "unintended discrepancy" between the timing when the "first injection start signal" reaches the hydraulic control unit 300A and the timing when the "second injection start signal" reaches the hydraulic control unit 300B. However, in embodiment 1, as described above, the hydraulic control unit 300A is configured to output the "first command signal" to the servo amplifier 400A only after a predetermined time X has elapsed, after receiving not only the "first injection start signal" but also the "synchronization signal" generated by the synchronization signal generation unit 600. Similarly, in embodiment 1, the hydraulic control unit 300B is configured to output the "second command signal" to the servo amplifier 400B only after a predetermined time X has elapsed, after receiving not only the "second injection start signal" but also the "synchronization signal" generated by the synchronization signal generation unit 600.

[0095] Therefore, in embodiment 1, it is possible to avoid the manifestation of an "unintended discrepancy" between the timing at which the "first injection start signal" reaches the hydraulic control unit 300A and the timing at which the "second injection start signal" reaches the hydraulic control unit 300B due to communication issues, and as a result, the timing at which the "first command signal" is output and the timing at which the "second command signal" is output can be synchronized.

[0096] (Factor 2) The synchronization signal generation unit 600 is composed of one synchronization signal output board.

[0097] For example, the "synchronization signal" is generated based on a "synchronization signal generation command" output from the central control unit 200 via communication. In this case, since the synchronization signal generation unit 600 is composed of a single synchronization signal output board, there is no room for "unintended delays" due to communication in the "synchronization signal generation command" output from the central control unit 200, and the "synchronization signal" does not need to consider "unintended delays" caused by communication. Furthermore, since the "synchronization signal" output from the synchronization signal generation unit 600 is a logic signal based on a change in potential rather than communication, there is almost no delay between the input timing of the "synchronization signal" to the hydraulic control unit 300A and the input timing of the "synchronization signal" to the hydraulic control unit 300B.

[0098] Therefore, in embodiment 1, while it is obvious that a configuration using a "synchronization signal" is employed, the synergistic effect of factors 1 and 2 described above also has great technical significance in order to synchronize the timing of outputting the "first command signal" from the hydraulic control unit 300A to the servo amplifier 400A with the timing of outputting the "second command signal" from the hydraulic control unit 300B to the servo amplifier 400B.

[0099] <<Technical significance of providing a predetermined time measurement unit>> Here, the first predetermined time measurement unit 700A and the second predetermined time measurement unit 700B will be collectively referred to as the predetermined time measurement unit. The technical significance of providing the predetermined time measurement unit will be explained below.

[0100] In the above-described embodiment 1, the timing of outputting the "first command signal" from the hydraulic control unit 300A to the servo amplifier 400A and the timing of outputting the "second command signal" from the hydraulic control unit 300B to the servo amplifier 400B are synchronized by using the "synchronization signal" generated by the synchronization signal generation unit 600. According to this embodiment 1, it is basically possible to suppress "unintended discrepancies" between the first injection start timing in the injection device 2A and the injection start timing in the second injection device, thereby achieving the remarkable effect of suppressing unevenness in the material filling state in the sealed space of the mold clamping device.

[0101] Therefore, it can be argued that if a "synchronization signal" is used, a predetermined time measurement unit is not necessarily required. In other words, for example, the hydraulic control unit 300A outputs the "first command signal" to the servo amplifier 400A only after a predetermined time X has elapsed, after receiving not only the "first injection start signal" but also the "synchronization signal" generated by the synchronization signal generation unit 600. However, if the sole purpose is to synchronize, the predetermined time X can be set to "zero," so it can be argued that there is no need to provide a predetermined time measurement unit.

[0102] However, for example, in injection devices 2A and 2B, differences in mechanical injection operation may occur, and differences in load may occur depending on the state of the material in cylinders 22A and 22B. As a result, even if the "first command signal" output from the hydraulic control unit 300A and the "second command signal" output from the hydraulic control unit 300B are synchronized, there is a possibility of an "unintended discrepancy" between the first injection start timing in injection device 2A and the injection start timing in the second injection device. For this reason, even if embodiment 1 is adopted, it may not be possible to completely suppress unevenness in the material filling state in the sealed space of the mold clamping device.

[0103] Therefore, in order to absorb "unintended deviations" caused by differences in machines or loads, it is conceivable to suppress bias in the material injected from each of the injection devices 2A and 2B by intentionally shifting the output timing of the "first command signal" output from the hydraulic control unit 300A and the output timing of the "second command signal" output from the hydraulic control unit 300B by a predetermined time. In this regard, the predetermined time measurement unit described above plays an important role in realizing a configuration in which the output timing of the "first command signal" output from the hydraulic control unit 300A and the output timing of the "second command signal" output from the hydraulic control unit 300B are intentionally shifted by a predetermined time. That is, for example, by setting the first predetermined time measured by the first predetermined time measurement unit 700A and the second predetermined time measured by the second predetermined time measurement unit 700B to different values, a configuration in which the output timing of the "first command signal" output from the hydraulic control unit 300A and the output timing of the "second command signal" output from the hydraulic control unit 300B are intentionally shifted can be easily realized.

[0104] Therefore, the significant technical importance of providing a predetermined time measurement unit lies in easily realizing a configuration in which the output timing of the "first command signal" output from the hydraulic control unit 300A and the output timing of the "second command signal" output from the hydraulic control unit 300B are intentionally shifted by a predetermined time, in order to absorb "unintended discrepancies" caused by differences in machines or loads.

[0105] The following describes this embodiment 2.

[0106] <Manifestation Method 2 (Intentional Time Delay)> <<Configuration of the Distributed Control System>> The distributed control system in embodiment 2 has basically the same configuration as the distributed control system in embodiment 1 described above. However, in embodiment 2, the first predetermined time measured by the first predetermined time measurement unit 700A and the second predetermined time measured by the second predetermined time measurement unit 700B are set to different values. For example, the first predetermined time measured by the first predetermined time measurement unit 700A is set to predetermined time X, while the second predetermined time measured by the second predetermined time measurement unit 700B is set to predetermined time Y.

[0107] <<Operation of the Distributed Control System>> Figure 7 is a flowchart illustrating the operation of the distributed control system in embodiment 2, and the operation of this distributed control system will be explained using Figures 5 and 7.

[0108] First, the central control unit 200 outputs a "first injection start signal" to the hydraulic control unit 300A of the injection device 2A via communication, and also outputs a "second injection start signal" to the hydraulic control unit 300B of the injection device 2B (S201). The "first injection start signal" output from the central control unit 200 is input to the hydraulic control unit 300A of the injection device 2A, while the "second injection start signal" output from the central control unit 200 is input to the hydraulic control unit 300B of the injection device 2B.

[0109] Here, even when the hydraulic control unit 300A receives the "first injection start signal," it remains in a waiting state without immediately outputting the "first command signal" to the servo amplifier 400A. Similarly, even when the hydraulic control unit 300B receives the "second injection start signal," it remains in a waiting state without immediately outputting the "second command signal" to the servo amplifier 400B.

[0110] Furthermore, the central control unit 200 outputs a "synchronization signal generation command" to the synchronization signal generation unit 600 via communication (S202). The synchronization signal generation unit 600 then generates a "synchronization signal" based on the "synchronization signal generation command" output from the central control unit 200 (S203). Subsequently, the "synchronization signal" generated by the synchronization signal generation unit 600 is input to the hydraulic control unit 300A and the hydraulic control unit 300B, respectively (S204A, S204B).

[0111] When a "synchronization signal" is input to the hydraulic control unit 300A, the first predetermined time measurement unit 700A starts measuring a predetermined time X that has been set in advance (S205A). Then, when the measurement of the predetermined time X by the first predetermined time measurement unit 700A is completed, the first command signal output unit 800A outputs a "first command signal" to the servo amplifier 400A (S206A).

[0112] Similarly, when a "synchronization signal" is input to the hydraulic control unit 300B, the second predetermined time measurement unit 700B starts measuring a predetermined time Y that has been set in advance (S205B). Then, when the measurement of the predetermined time Y by the second predetermined time measurement unit 700B is completed, the second command signal output unit 800B outputs a "second command signal" to the servo amplifier 400A (S206B).

[0113] Thus, the hydraulic control unit 300A simply waits even after receiving the "first injection start signal" output from the central control unit 200, and does not output the "first command signal" to the servo amplifier 400A. Furthermore, after receiving the "synchronization signal" generated by the synchronization signal generation unit 600, the "first command signal" is output to the servo amplifier 400A only after a predetermined time X has elapsed.

[0114] In contrast, the hydraulic control unit 300B also simply waits even after receiving the "second injection start signal" output from the central control unit 200, and does not output the "second command signal" to the servo amplifier 400B. Furthermore, after receiving the "synchronization signal" generated by the synchronization signal generation unit 600, the "second command signal" is output to the servo amplifier 400B only after a predetermined time Y has elapsed.

[0115] As a result, in embodiment 2, the timing at which the "first command signal" is output to servo amplifier 400A and the timing at which the "second command signal" is output to servo amplifier 400B are intentionally shifted by a time difference (YX). This causes the injection operation to start in injection devices 2A and 2B with a time difference (YX) between them.

[0116] Next, the "first command signal" output from the hydraulic control unit 300A is input to the servo amplifier 400A. The servo amplifier 400A then supplies output to the servo valve 505A to achieve the opening degree indicated by the target value in the "first command signal" (S207A). As a result, the opening degree of the servo valve 505A changes based on the power output from the servo amplifier 400A.

[0117] Subsequently, the opening of the servo valve 505A changes, which adjusts the flow rate of the oil and controls the hydraulic pressure required to move the piston 27A. In other words, for example, by controlling the opening of the servo valve 505A and increasing the hydraulic pressure applied to the piston 27A, the piston 27A moves forward. This causes the screw 23A connected to the piston 27A to move forward, and the moving screw 23A injects the molten material from the nozzle towards the clamping device (see Figure 3). In this way, the injection device 2A operates (S208A).

[0118] Meanwhile, the "second command signal" output from the hydraulic control unit 300B is input to the servo amplifier 400B. The servo amplifier 400B then supplies output to the servo valve 505B to achieve the opening degree indicated by the target value in the "second command signal" (S207B). As a result, the opening degree of the servo valve 505B changes based on the power output from the servo amplifier 400A.

[0119] Subsequently, the opening of the servo valve 505B changes, which adjusts the flow rate of the oil and controls the hydraulic pressure required to move the piston 27B. In other words, for example, by controlling the opening of the servo valve 505B and increasing the hydraulic pressure applied to the piston 27B, the piston 27B moves forward. This causes the screw 23B connected to the piston 27B to move forward, and the moving screw 23B injects the molten material from the nozzle towards the clamping device (see Figure 3). In this way, the injection device 2B operates (S208B).

[0120] Here, assuming that an "unintended discrepancy" (let's call it a time difference Z) occurs between the injection operation of injection device 2A, indicated by "S208A," and the injection operation of injection device 2B, indicated by "S208B," due to differences in machine operation and load, in embodiment 2, the injection start timing in injection device 2A and the injection start timing in injection device 2B are intentionally shifted by a time difference (YX). Thus, according to embodiment 2, the time difference between the injection start timing in injection device 2A and the injection start timing in injection device 2B can be made smaller than the "unintended discrepancy" (time difference Z) caused by differences in machine operation and load, resulting in "time difference Z - time difference (YX)." In particular, if the intentional time difference (YX) between the timing at which the "first command signal" is output to servo amplifier 400A and the timing at which the "second command signal" is output to servo amplifier 400B can be made approximately equal to the "unintentional deviation" (time difference Z) caused by machine differences and load differences, the "unintentional deviation" (time difference Z) will be canceled out by the time difference (YX). As a result, the time difference between the injection start timing in injection device 2A and the injection start timing in injection device 2B can be brought as close to zero as possible.

[0121] <<Characteristics of Embodiment Mode 2>> Next, we will explain the characteristics of the second embodiment.

[0122] A key feature of embodiment 2 is that a time difference is intentionally set between the timing of outputting the "first command signal" to servo amplifier 400A and the timing of outputting the "second command signal" to servo amplifier 400B, in order to absorb "unintended deviations" caused by differences in machines or loads. In embodiment 2, by intentionally shifting the output timing of the "first command signal" in injection device 2A and the output timing of the "second command signal" in the second injection device by a predetermined time, it is possible to suppress the bias of the material injected from injection device 2A and injection device 2B, respectively, in order to absorb (preferably cancel out) "unintended deviations" caused by differences in machines or loads.

[0123] For example, setting a predetermined time difference between the timing of outputting the "first command signal" to servo amplifier 400A and the timing of outputting the "second command signal" to servo amplifier 400B can be done as follows. That is, the predetermined time X measured by the first predetermined time measurement unit 700A and the predetermined time Y measured by the second predetermined time measurement unit 700B can be set, for example, as follows.

[0124] Specifically, by operating the "twin injection molding machine" in advance and acquiring data on "unintended deviations" caused by differences in machines and loads, it is possible to identify "unintended deviations" based on this data and set the time difference (YX) between a predetermined time X measured by the first predetermined time measurement unit 700A and a predetermined time Y measured by the second predetermined time measurement unit 700B to offset the identified "unintended deviations".

[0125] Furthermore, assuming that the material in the cylinders of injection unit 2A and injection unit 2B is equivalent, if the remaining amounts are the same, it is highly likely that the amount of material injected will also be the same. Considering this, the "twin injection molding machine" can automatically set a predetermined time difference as follows. For example, the remaining amounts of material after injection holding pressure in injection unit 2A and injection unit 2B are measured and compared. Then, a correction amount is calculated according to the difference in remaining amounts obtained from the comparison result, and the calculated correction amount is set as the time difference (YX) between a predetermined time X measured by the first predetermined time measurement unit 700A and a predetermined time Y measured by the second predetermined time measurement unit 700B. In this way, the time difference between the timing of outputting the "first command signal" to servo amplifier 400A and the timing of outputting the "second command signal" to servo amplifier 400B can be automatically set so that the remaining amounts of material in injection unit 2A and injection unit 2B are equivalent.

[0126] <<Variation>> In Embodiment 1, an example of a configuration in which the "injection start signal" input to the hydraulic control unit 300A and the "injection start signal" input to the hydraulic control unit 300B are synchronized was described. However, the technical concept in the embodiment is not limited to this, and for example, it may be configured to synchronize the "first command signal" input to the servo amplifier 400A and the "second command signal" input to the servo amplifier 400B. In this case, the signals can be synchronized downstream of the distributed control system, which is closer to the servo valve 505A and the servo valve 505B, thus reducing the time lag associated with downstream processing after synchronization. As a result, the advantage is obtained in which the difference between the first injection start timing in the injection device 2A and the second injection start timing in the injection device 2B can be further reduced.

[0127] Furthermore, although the description in Embodiment 1 was based on the premise that the synchronization signal generation unit 600 is provided on a separate synchronization signal output board different from the "first control board" (hydraulic control unit 300A) and the "second control board" (hydraulic control unit 300B), the technical concept in the embodiment is not limited to this, and the synchronization signal generation unit 600 may be provided on the "first control board" or the "second control board," or it may be provided across both the "first control board" and the "second control board."

[0128] The present invention has been described in detail above based on its embodiments, but it goes without saying that the present invention is not limited to the above embodiments and can be modified in various ways without departing from its essence. [Explanation of symbols]

[0129] 1 Mold clamping device 2A injection device 2B Injection device 10 Movable plate 11 Fixed plate 12 Movable type 13 Fixed type 21A Hopper 22A CAL 23A Screw 24A Screw Rotation Motor 25A heater 26A Nozzle 27A Piston 28A Hydraulic System 100 Twin Injection Molding Machines 200 Central Control Unit 300A Hydraulic Control Unit 300B Hydraulic Control Unit 400A Servo Amplifier 400B Servo Amplifier 501A Accumulator 501B Accumulator 502A Pump 502B Pump 503A channel 503B channel 504A channel 504B channel 505A Servo Valve 505B Servo Valve 600 Synchronization signal generation unit 700A First predetermined time measurement unit 700B Second predetermined time measurement unit 800A First Command Signal Output Unit 800B 2nd command signal output section

Claims

1. A central control unit that provides overall control over the injection molding operation, A first injection device that performs a material injection operation based on a first injection start signal for the first injection device output from the central control unit, A second injection device that performs a material injection operation based on a second injection start signal for the second injection device output from the central control unit, A clamping device that performs the clamping operation, An injection molding machine equipped with, The injection molding machine is configured to adjust the time difference between the first injection start timing of the material from the first injection device and the second injection start timing of the material from the second injection device. The first injection device is A first control unit that outputs a first command signal based on the first injection start signal, A first servo amplifier controls the opening degree of the first servo valve based on the first command signal, The first servo valve, whose opening degree is controlled by the first servo amplifier, It has, The second injection device is, A second control unit that outputs a second command signal based on the second injection start signal, A second servo amplifier controls the opening degree of the second servo valve based on the second command signal, The second servo valve, whose opening degree is controlled by the second servo amplifier, It has, The injection molding machine has a synchronization signal generation unit that generates a synchronization signal based on a command output from the central control unit and outputs the generated synchronization signal to the first control unit of the first injection device and the second control unit of the second injection device. The first control unit is, When the synchronization signal output from the synchronization signal generation unit is input, a first predetermined time measurement unit measures the elapsed time since the synchronization signal was input, A first command signal output unit outputs the first command signal to the first servo amplifier after the elapsed time measured by the first predetermined time measurement unit, It has, The second control unit is, When the synchronization signal output from the synchronization signal generation unit is input, a second predetermined time measurement unit measures the elapsed time since the synchronization signal was input, A second command signal output unit outputs the second command signal to the second servo amplifier after the second predetermined time measured by the second predetermined time measurement unit has elapsed, An injection molding machine having [a specific feature / feature].

2. In the injection molding machine according to claim 1, An injection molding machine in which the first predetermined time and the second predetermined time are equal.

3. In the injection molding machine according to claim 1, An injection molding machine in which the first predetermined time and the second predetermined time are different.

4. In the injection molding machine according to claim 1, An injection molding machine wherein the first injection start signal is output from the central control unit to the first injection device via communication, and the second injection start signal is also output from the central control unit to the second injection device via communication.

5. In the injection molding machine according to claim 1, The injection operation in the first injection device is performed by the first servo valve. An injection molding machine in which the injection operation in the second injection device is performed by the second servo valve.

6. In the injection molding machine according to claim 5, The first control unit is a first hydraulic control unit, The second control unit is a second hydraulic control unit, The hydraulic pressure is controlled by the first servo valve, An injection molding machine in which hydraulic pressure is controlled by the second servo valve.

7. In the injection molding machine according to claim 1, The aforementioned material is an injection molding machine containing magnesium.

8. The process includes adjusting the time difference between the first injection start timing of the material from the first injection device, which performs the material injection operation based on a first injection start signal for the first injection device output from the central control unit that comprehensively controls the injection molding operation, and the second injection start timing of the material from the second injection device, which performs the material injection operation based on a second injection start signal for the second injection device output from the central control unit. (a) A step of generating a synchronization signal in the synchronization signal generation unit based on a command from the central control unit, (b) A step of controlling the first injection device, (c) A step of controlling the second injection device, It has, The above step (b) is, (b1) A step of inputting the first injection start signal to the first control unit, (b2) A step of inputting the synchronization signal to the first control unit, (b3) A step of measuring the elapsed time of a first predetermined time since the synchronization signal was input, (b4) After the elapsed time of the first predetermined time measured in step (b3), the first control unit outputs a first command signal to the first servo amplifier. (b5) A step of controlling the opening degree of the first servo valve with the first servo amplifier, Includes, The above step (c) is, (c1) A step of inputting the second injection start signal to the second control unit, (c2) A step of inputting the synchronization signal to the second control unit, (c3) A step of measuring the elapsed time of a second predetermined time since the synchronization signal was input, (c4) After the elapsed time of the second predetermined time measured in step (c3), the second control unit outputs a second command signal to the second servo amplifier. (c5) A step of controlling the opening degree of the second servo valve with the second servo amplifier, A control method for an injection molding machine, including [the specified element].

9. In the control method for an injection molding machine according to claim 8, A control method for an injection molding machine, wherein the first predetermined time and the second predetermined time are equal.

10. In the control method for an injection molding machine according to claim 8, A control method for an injection molding machine, wherein the first predetermined time and the second predetermined time are different.

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