Molding apparatus, control method, and control program

Abstract

To solve the problem that it is difficult to improve production efficiency including the number of products in a conventional control method.SOLUTION: A molding apparatus according to an embodiment includes at least one pump including a motor capable of changing a rotation speed, a hydraulic control device configured to control a hydraulic pressure by controlling the motor based on one control pattern selected from a plurality of control patterns of the motor stored in a storage unit, and a power monitor configured to measure power consumption by at least the motor. The hydraulic control device performs a power monitoring process (S1 to S5) of performing a forming cycle of controlling the pump based on a control pattern and measuring power consumption during the forming cycle by a power monitor, a production performance indicator calculation process (S6) of calculating a production performance indicator including at least the power consumption during the forming cycle and a time required for the forming cycle, and a control pattern verification process (S7 to S8) of performing the power monitoring process and the production performance indicator calculation process for each of the plurality of control patterns.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a molding apparatus including, for example, an injection molding machine that generates pressure by hydraulic pressure, a control method, and a control program. [Background technology]

[0002] Molding devices such as injection molding machines are configured by combining many electrically driven devices such as motors, pumps, and heating devices. Therefore, there is a demand for reducing the power consumption of molding devices. Patent Document 1 discloses an example of a technology for reducing power consumption in molding devices.

[0003] The injection molding machine described in Patent Document 1 is an injection molding machine operated by both a mechanical drive mechanism driven by an electric motor and a pressure mechanism driven by a pressure medium sent from a pump, and is equipped with a power regeneration means that regenerates power generated by the electric motor when the mechanical drive mechanism decelerates, and a rotation speed control means that controls the rotation speed of the pump. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-77725 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the focus is solely on reducing power consumption, it is conceivable that the time required for one molding cycle will be longer, resulting in a decrease in the number of units produced, etc. Patent Document 1 does not disclose or suggest anything about improving production efficiency in terms of productivity, including power consumption and the time required for a molding cycle.

[0006] The present invention has been made in view of the above circumstances, and has as its object to improve the productivity of a molding apparatus. Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0007] A molding apparatus according to one embodiment is a molding apparatus including a hydraulic mechanism that drives a mechanism using hydraulic pressure, and includes at least one pump equipped with a motor whose rotation speed can be changed, a hydraulic control device that controls the motor to control the hydraulic pressure based on one control pattern selected from a plurality of control patterns for the motor stored in a memory unit, and a power monitor that measures at least the power consumed by the motor, and the hydraulic control device performs a power monitoring process that performs a molding cycle that controls the pump based on the control pattern and measures the power consumed during the molding cycle using the power monitor, a productivity index calculation process that calculates a productivity index that includes at least the power consumed during the molding cycle and the time required for the molding cycle, and a control pattern verification process that performs the power monitoring process and the productivity index calculation process for each of the plurality of control patterns.

[0008] A control method according to one embodiment is a control method for a molding device having a hydraulic mechanism that drives a mechanism using hydraulic pressure, wherein the hydraulic mechanism includes at least one pump equipped with a motor whose rotation speed is adjustable, a hydraulic control device that controls the motor to control the hydraulic pressure based on one control pattern selected from a plurality of control patterns for the motor stored in a memory unit, and a power monitor that measures at least the power consumption by the motor, wherein the hydraulic control device performs a power monitoring process in which the hydraulic control device executes a molding cycle that controls the pump based on the control pattern and measures the power consumption during the molding cycle using the power monitor, a productivity index calculation process that calculates a productivity index that includes at least the power consumption during the molding cycle and the time required for the molding cycle, and a control pattern verification process in which the power monitoring process and the productivity index calculation process are performed for each of the plurality of control patterns.

[0009] A control program according to one embodiment is a control program executed by a calculation unit in a molding apparatus having a hydraulic mechanism that drives a mechanism by hydraulic pressure, the control program including at least one pump equipped with a motor whose rotation speed is changeable, a hydraulic control device that controls the motor to control the hydraulic pressure based on one control pattern selected from a plurality of control patterns of the motor stored in a memory unit, and a power monitor that measures at least the power consumed by the motor, the control program performing a power monitoring process that performs a molding cycle that controls the pump based on the control pattern and measures the power consumed during the molding cycle using the power monitor, a productivity index calculation process that calculates a productivity index that includes at least the power consumed during the molding cycle and the time required for the molding cycle, and a control pattern verification process that performs the power monitoring process and the productivity index calculation process for each of the plurality of control patterns.

[0010] In the molding apparatus, the control method, and the control program according to one embodiment, a productivity index is calculated for each of a plurality of control patterns. [Effects of the Invention]

[0011] According to the molding apparatus, the control method, and the control program of the embodiment, it is possible to increase the productivity of the molding apparatus. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a configuration diagram illustrating an outline of a molding device according to a first embodiment. [Figure 2] 4 is a diagram illustrating the relationship between motor rotation speed control and oil pressure in the molding device according to the first embodiment. FIG. [Figure 3] FIG. 3 is a diagram illustrating the relationship between the rotation speed of the motor and the overall efficiency of the pump in the molding device according to the first embodiment. [Figure 4] 1 is a block diagram of a hydraulic control device according to a first embodiment. [Figure 5] 4 is a flowchart illustrating the operation of the molding device according to the first embodiment. [Figure 6] FIG. 10 is a block diagram of a hydraulic control device according to a second embodiment. [Figure 7] FIG. 10 is a block diagram of a hydraulic control device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] For clarity of explanation, the following description and drawings have been omitted and simplified as appropriate. Furthermore, each element shown in the drawings as a functional block performing various processes can be configured in hardware with a CPU (Central Processing Unit), memory, and other circuits, and in software with a program loaded into memory, etc. Therefore, those skilled in the art will understand that these functional blocks can be realized in various forms using only hardware, only software, or a combination thereof, and are not limited to any one of these. In addition, the same elements are designated by the same reference numerals in each drawing, and redundant explanations are omitted as necessary.

[0014] Furthermore, the above-described program includes a set of instructions (or software code) that, when loaded into a computer, causes the computer to perform one or more functions described in the embodiments. The program may be stored in a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable media or tangible storage media include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD-ROM, digital versatile disc (DVD), Blu-ray (registered trademark) disc or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The program may also be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, transitory computer-readable media or communication media include electrical, optical, acoustic, or other forms of propagated signals.

[0015] <First Embodiment> Molding devices include injection molding devices that inject resin into a cavity formed in a mold by combining molds to form a resin molded product, and press molding devices and laminate molding devices that pressurize two overlapping flat plates to form a laminate molded product. These molding devices include a hydraulic mechanism that drives the mechanism with hydraulic pressure, and the pump mechanism is controlled by a motor with a variable rotation speed. Below, a control method for a pump equipped with a motor with a variable rotation speed will be described using an injection molding device as an example, but the control method described in the following embodiments can be applied to all devices that use pumps, such as press molding devices and laminate molding devices.

[0016] Fig. 1 shows a schematic diagram illustrating a molding apparatus 1 according to the first embodiment. As shown in Fig. 1, the molding apparatus 1 according to the first embodiment is a system for hydraulically driving an injection molding machine 10 using at least hydraulic oil. In Fig. 1, cross sections of parts that cannot be seen from the outside of the injection molding machine 10 are shown within hatched areas.

[0017] As shown in Figure 1, injection molding machine 10 includes components of a mold clamping device, such as a fixed platen 11, a movable platen 12, tie bars 13, molds 14 and 15, an injection nozzle 16, a movable platen movement mechanism 17, a half-nut lock mechanism 18, and a mold clamping cylinder 19, as well as components of an injection device, such as an injection nozzle 16 and a drive mechanism for driving a screw built into a heating cylinder to which the injection nozzle is attached. The components of injection molding machine 10 shown in Figure 1 are the main components of injection molding machine 10, and may also include components not shown. Furthermore, molds 14 and 15 are often not included in injection molding machine 10 at the distribution stage.

[0018] The fixed platen 11 is fixed to a base, and a mold 15 is removably fixed thereto. In the example shown in FIG. 1 , a hole through which an injection nozzle 16 is inserted is formed in the fixed platen 11, and the injection nozzle 16 can come into contact with the nozzle touch portion of the fixed mold 14 through the hole in the fixed platen 11. Resin is injected from the injection nozzle 16 through the nozzle touch hole toward a cavity formed between the mold 14 and the mold 15. The injection unit including the injection nozzle 16 is configured to move back and forth by, for example, a nozzle touch cylinder (not shown). A mold clamping cylinder 19 is also provided on the fixed platen 11. Note that a hydraulic drive mechanism for driving the nozzle touch cylinder also uses a hydraulic pump, and this hydraulic drive mechanism is also controlled by a system control device 32, which will be described later.

[0019] The tie bars 13 are provided near the four corners of the fixed platen 11. Furthermore, insertion holes, through which the tie bars 13 are inserted, are provided near the four corners of the movable platen 12, and the tie bars 13 are inserted into these insertion holes. The movable platen 12 is provided so as to be movable in the left-right direction in the drawing by a movable platen moving mechanism 17. Furthermore, a mold 15 is removably fixed to the movable platen 12. The molds 14 and 15 are attached to an area sandwiched between the fixed platen 11 and the movable platen 12. Furthermore, a half nut lock mechanism 18 is attached to the surface of the movable platen 12 opposite to the surface to which the mold 15 is attached. The half nut lock mechanism 18 has half nuts that fit into grooves engraved on the outer peripheral surfaces of the tie bars 13, and by fitting these half nuts into the grooves of the tie bars 13, the movable platen 12 is substantially integrated with the tie bars 13.

[0020] 1, the clamping cylinder 19 is a hydraulic cylinder. The clamping cylinder 19 has a piston fixed to the tie bar 13, and moves the piston in a direction in which the fixed platen 11 and the movable platen 12 approach each other (hereinafter referred to as the clamping direction), thereby moving the tie bar 13 in the clamping direction. In the example shown in FIG. 1, the half nut lock mechanism 18 also includes a hydraulic cylinder, and has a cylinder that moves the piston inside the hydraulic cylinder to move the half nut in a direction to engage with the tie bar 13 or in a direction to release the engagement. In addition, for the movable platen moving mechanism 17, a hydraulic cylinder may be used instead of an electric mechanism.

[0021] As described above, the injection molding machine 10 incorporates many hydraulic cylinders that hydraulically operate various components. In the injection molding machine 10, components operated by hydraulic cylinders and components operated by electric mechanisms are combined in consideration of operational accuracy, operational speed, energy consumption, and device cost, and hydraulic oil is used to drive these hydraulic cylinders. The molding apparatus 1 according to the first embodiment is provided with many pipes for supplying and discharging the hydraulic oil to and from the hydraulic cylinders in the injection molding machine 10, and these pipes are equipped with valves and oil pumps. Specifically, the molding apparatus 1 according to the first embodiment includes an oil distribution flow path and an oil storage tank 20 in addition to the injection molding machine 10. The oil distribution flow path includes hydraulic cylinders (multiple hydraulic cylinders provided in the injection molding machine 10, including the clamping cylinder 19) and a hydraulic oil path between the hydraulic cylinders and the oil storage tank 20. The oil distribution path is equipped with various devices, including an oil supply pump 21, a check valve 22, a pressure control valve 23, and a directional control valve 24.

[0022] Here, the hydraulic oil piping that forms part of the oil distribution flow path, and the valves and oil feed pump 21 that are arranged on the piping will be described in detail. As shown in FIG. 1, in the molding apparatus 1 according to the first embodiment, piping is provided to connect an oil storage tank 20 to each of a plurality of hydraulic cylinders. The piping is provided with a plurality of valves that switch the path through which the hydraulic oil flows and control the flow rate of the hydraulic oil, and at least one oil feed pump 21 that pressurizes the hydraulic oil. In the example shown in FIG. 1, only the oil feed pump 21 is shown on the piping that forms the hydraulic oil path, but there may also be other pumps that receive power from an AC power source 30 (described later) and are controlled by a system control device 32.

[0023] Here, the valves shown in FIG. 1 will be described. The check valve 22 is a check valve that prevents hydraulic oil delivered from the oil feed pump 21 from flowing back from the cylinder side to the oil feed pump 21 side. The pressure control valve 23 is located closer to the hydraulic cylinder than the check valve 22 and controls the pressure of the hydraulic oil in the piping on the cylinder side. The directional control valve 24 switches between sending and discharging hydraulic oil to the hydraulic cylinder. While FIG. 1 only shows the directional control valve 24 provided for the illustrated mold clamping cylinder 19, a directional control valve 24 can be provided for each of multiple cylinders. The directional control valve 24 switches the hydraulic oil flow path, and this is performed by the system control device 32. Note that the supply of hydraulic oil to the hydraulic cylinder can also be controlled by using a cartridge valve or the like instead of the directional control valve 24. The pressure control valve may be provided at the point where hydraulic oil is discharged from the oil feed pump 21 to measure the pump's source pressure, or it may be provided in each piping that delivers hydraulic oil to each mold clamping cylinder 19.

[0024] As shown in FIG. 1, in the molding apparatus 1 according to the first embodiment, power is supplied from an AC power source 30 to the oil feed pump 21. In the molding apparatus 1, the destination of the power supply from the AC power source 30 is not limited to the oil feed pump 21, but the power is supplied from the AC power source 30 to the entire interior of the molding apparatus 1. In the molding apparatus 1 according to the first embodiment, the amount of power supplied from the AC power source 30 to the entire molding apparatus 1 is acquired by a power monitor 31. In the molding apparatus 1 according to the first embodiment, the operation of the molding apparatus 1 is controlled using a system control device 32. In FIG. 1, a hydraulic control device 33 that controls the rotation speed of the motor included in the oil feed pump 21 is shown as part of the system control device 32. Also shown is an interface that provides the system control device 32 with information such as molding conditions and control patterns stored in the hydraulic control device 33, as well as operational instructions for the molding apparatus 1, and a display unit 34 that serves as an interface that displays the operational status of the molding apparatus 1 to the operator.

[0025] In the molding apparatus 1 according to the first embodiment, one of its features lies in the configuration and operation of the hydraulic control device 33, and therefore the hydraulic control device 33 will be described in more detail below. In the molding apparatus 1 according to the first embodiment, it is also possible to control the motor using a control pattern that defines the state in which the motor is controlled over time during molding operations. This control pattern may, for example, define the time-series change in the rotation speed of the motor, define the time-series change in the torque of the motor, or define the time-series change in the hydraulic pressure output by the pump. In the following explanation, the molding apparatus 1 will be described using an example in which the control pattern defines the time-series change in the rotation speed of the motor (an example in which the control pattern is a rotation speed control pattern that indicates the rotation speed of the motor).

[0026] Fig. 2 shows a diagram for explaining the relationship between motor rotation speed control and hydraulic pressure in the molding apparatus 1 according to the first embodiment, and Fig. 3 shows a diagram for explaining the relationship between motor rotation speed and overall efficiency of the pump in the molding apparatus according to the first embodiment. Control patterns will be explained using Fig. 2 and Fig. 3. Note that Fig. 2 and Fig. 3 explain control patterns only for the portion related to the mold clamping operation in one molding cycle.

[0027] In Figure 2, the lower graph shows a control pattern that defines the time-series changes in the motor's rotational speed, while the upper graph shows the changes in hydraulic oil pressure associated with pump operation. In the control pattern shown in the lower graph of Figure 2, the pump starts before mold clamping begins, and the motor's rotational speed is set to a specified speed or higher to coincide with the start of mold clamping. Then, after the half nut contacts the tie bar, high pressure is applied to the cylinder to increase the clamping pressure. During this period of increasing the clamping pressure, if the hydraulic oil pressure rises, even if a rotation command value above the rated rotational speed is output, the motor may become overloaded. This reduces the overall efficiency of the pump relative to the rotational speed. Therefore, the rotational speed is slightly lower than before the half nut contacts the tie bar. However, this does not completely rule out using the pump at a speed above the rated rotational speed for short periods of time. After the time to maintain the mold clamping state is reached, the motor's minimum rotational speed is maintained to maintain hydraulic pressure. Alternatively, the motor's rotational speed is stopped and the motor is turned on only when the pressure drops. In the control pattern, the motor's rotational speed is specified, for example, every 0.1 seconds. In FIG. 2, some of the motor rotational speeds defined for every 0.1 seconds are shown as timings a to g.

[0028] Here, reference is made to Figure 3. Figure 3 shows the overall efficiency curve of the pump when the pressure applied to the hydraulic fluid by the pump is a first pressure (e.g., 15 MP), and the overall efficiency curve of the pump when the pressure applied to the hydraulic fluid by the pump is a second pressure (e.g., 5 MP) lower than the first pressure. As such, the overall efficiency of the pump tends to be higher when a high hydraulic pressure is generated, particularly in the high rotational speed range. Also, as shown in Figure 3, the overall efficiency of the pump tends to be higher when the motor is rotated at a rotational speed lower than the rated rotational speed but above a certain rotational speed.

[0029] Furthermore, Figure 3 shows the overall efficiency of the pump at times a to g shown in Figure 2. As shown in Figure 3, in relation to the rotation speed, the rated rotation speed is exceeded between times b, c, and d, but when full-scale pressure increase begins, where the oil pressure rises significantly, the rotation speed command value becomes the rated rotation speed or slightly lower. In this case, it is better to extend the pump operation time when the pump overall efficiency is high as much as possible in order to reduce power consumption.

[0030] Therefore, in the molding apparatus 1 according to the first embodiment, multiple control patterns are prepared in advance, each of which varies over time with the rotational speed of the motor. For example, a first control pattern sets the rotation speed at 1,000 rpm at timing a, 2,000 rpm at timings b through d, and 1,800 rpm at timings e through g. A second control pattern sets the rotation speed at 1,500 rpm at timing a, 2,000 rpm at timings b through c, 1,800 rpm at timings d through f, and 1,600 rpm at timing g. While these multiple control patterns may be input by an operator, in the first embodiment, multiple rule-based control patterns are prepared in the control program of the system control device 32 or its hydraulic control device 33. Furthermore, the number of control patterns prepared by the rule base is narrowed down or their values ​​are changed during multiple detections of productivity indicators, such as power consumption and the time required for molding operations. These control patterns may be reviewed using techniques using machine learning, such as reinforcement learning and backpropagation. Therefore, the present invention is not limited to executing control patterns based on a preset rule base, but may also involve using a neural network to estimate control patterns that are likely to be improved, and then trying out the control patterns in order, starting with the control pattern estimated to be the best.

[0031] In the molding apparatus 1 according to the first embodiment, a molding cycle is performed a predetermined number of times or for a predetermined time using different control patterns, and a productivity index is calculated that includes at least the power consumption when the molding cycle is performed according to each control pattern and the time required for the molding operation. By using this productivity index, it is possible to increase productivity when using the molding apparatus 1. There are various viewpoints for this productivity, but in the first embodiment, an example focusing on production profit as one type of productivity will be described.

[0032] Next, the hydraulic control device 33 according to the first embodiment will be described in detail. Fig. 4 shows a block diagram of the hydraulic control device 33 according to the first embodiment. In Fig. 4, processing blocks related to the hydraulic control device 33 are also shown to provide a better understanding of the hydraulic control device 33.

[0033] Specifically, in addition to the system control device 32, FIG. 4 shows an AC power supply 30, a power monitor 31, an oil feed pump 21, and a display unit 34. The AC power supply 30 supplies power to the entire molding apparatus 1. The power monitor 31 measures at least the power consumed by the motor. Note that the power consumption measured by the power monitor 31 may be only the power supplied to the servo motor 42 included in the oil feed pump 21, or may be the total power supplied to one or more upstream components other than the servo motor 42. By measuring the power of the upstream components of the injection molding machine 10, it is possible to take into account the negative factor of extra power consumption in other components when the molding cycle time is extended.

[0034] The oil feed pump 21 shown in FIG. 4 is one example of a pump configuration, and the configuration of the oil feed pump 21 is not limited to this. In the example shown in FIG. 4, the oil feed pump 21 has a servo amplifier 41, a servo motor 42, and a pump mechanism 43. The servo amplifier 41 controls the rotation speed of the servo motor 42 based on a command value given from the hydraulic control device 33. The servo motor 42 drives the pump mechanism 43. A rotary encoder (not shown) of the servo motor 42 measures the rotation speed of the servo motor and feeds it back to the servo amplifier 41. This allows the oil feed pump to achieve closed-loop control according to the command value. The pump mechanism 43 sends out hydraulic oil to an oil distribution path on the injection molding machine 10 side.

[0035] As shown in Fig. 4, the hydraulic control device 33 is implemented as part of the system control device 32. The system control device 32 and the hydraulic control device 33 can be configured with dedicated hardware, or can be configured with a computing device such as a computer having a computing unit capable of executing programs and a memory for storing data. Below, an example will be described in which the system control device 32 and the hydraulic control device 33 are configured with a computer that executes a control program. Furthermore, each process of the processing blocks described below may be performed by a single computer, or may be distributed among multiple computers connected via a network.

[0036] 4, the system control device 32 has a hydraulic control device 33 and a sequence control unit 35. In addition to the hydraulic control device 33 and the sequence control unit 35, the system control device 32 also includes various processing blocks for controlling parts of the molding apparatus 1 other than the oil feed pump 21, but these are not shown in FIG.

[0037] The sequence control unit 35 instructs each block in the system control device 32 on the overall operation sequence of the molding apparatus 1 during a molding cycle. The sequence control unit 35 instructs the hydraulic control device 33 on the timing of the mold closing operation, mold clamping operation, and mold opening operation. The hydraulic control device 33 then issues operation instructions to the oil feed pump 21 in accordance with the operation instructions for the mold closing operation, mold clamping operation, and mold opening operation that it has received. In addition, if the pump mechanism 43 uses a bidirectional rotary pump and is capable of backflowing hydraulic oil to the oil storage tank 20, when the hydraulic oil in the clamping cylinder 19 is depressurized after mold clamping is completed, the hydraulic oil is returned to the oil storage tank 20 via the pump mechanism 43. At this time, regenerative power is recovered using the servo motor 42, but a machine learning device may be used to generate and control command values ​​for depressurization so as to maximize the regenerative power.

[0038] The hydraulic control device 33 controls the motor based on one control pattern selected from multiple motor control patterns stored in the memory unit using a rule base predetermined by the machine learning device, thereby controlling the hydraulic pressure, including the flow rate. The hydraulic control device 33 also performs a power monitoring process (steps S1 to S5, described later with reference to FIG. 5 ) in which a molding cycle is performed to control the pump based on the control pattern and the power consumption during the molding cycle is measured using the power monitor 31. The hydraulic control device 33 also performs a productivity index calculation process (step S6, described later with reference to FIG. 5 ) in which a productivity index including at least the power consumption during a predetermined number of molding cycles or a predetermined time period and the time required to perform the predetermined number of molding cycles and / or a predetermined time period is calculated. Finally, the control pattern verification process (step S7, described later with reference to FIG. 5 ) in which the power monitoring process and the productivity index calculation process are performed for each of the multiple control patterns is performed. It goes without saying that the term "during a molding cycle" in the above does not refer only to a molding cycle divided into separate cycles for molding a molded product. For example, the term "during a molding cycle" may refer only to the mold clamping process, which is part of the molding cycle. Furthermore, the term "during a molding cycle" may refer to multiple molding cycles or a molding cycle over a predetermined period of time.

[0039] The productivity index calculation process in step 6 also involves the sales profit per molded product, or the sales amount and raw material costs. Therefore, these values ​​must also be input in advance as necessary. After the productivity indexes for all control patterns are collected, the hydraulic control device 33 according to the first embodiment selects a control pattern that maximizes the production profit per product, calculated based on the production quantity per unit time and power consumption, by referring to each productivity index, and continues molding operations in a production profit priority mode in which the pump is controlled using the selected control pattern.

[0040] The productivity index may also take into account the degree of deterioration due to differences in how the injection molding machine 10, including the oil feed pump 21, is used. Specifically, operating the oil feed pump 21 at a speed above its rated speed for a predetermined period of time may cause the motor to overload and deteriorate, or the rotating parts of the pump mechanism 43 to deteriorate. Therefore, the time the pump is operated at a speed above its rated speed, as well as the rotation speed, motor torque, and current value sent to the motor, may also be used to calculate the productivity index. Furthermore, the productivity index may also take environmental factors into account. Specifically, when selecting a control pattern, the reduction in power consumption during the molding cycle may be given greater weight than the fluctuation in profit due to changes in the number of molded pieces. This allows for the selection of a control pattern that further contributes to power consumption reduction, i.e., carbon neutrality.

[0041] An example of a configuration for carrying out the above-described operations is the configuration of the hydraulic control device 33 shown in Fig. 4. In the example shown in Fig. 4, the hydraulic control device 33 has a storage unit 51, a control pattern selection unit 52, a command value generation unit 53, a pattern evaluation unit 54, and a timer 55. The hydraulic control device 33 and its control program may be provided in the control device of the oil feed pump 21, in addition to the control device of the injection molding machine 10. Alternatively, the hydraulic control device 33 and its control program may be provided in a server or the like provided in a location remote from the injection molding machine 10.

[0042] The memory unit 51 stores multiple control patterns automatically and / or manually created by a user. The control pattern selection unit 52 selects one control pattern from the multiple control patterns stored in the memory unit 51 and provides it to the command value generation unit 53. This control pattern selection unit 52 selects a control pattern according to predetermined rules while executing a control pattern verification process, and selects the control pattern that maximizes production profits after the control pattern verification process is completed. The command value generation unit 53 provides a control command value (e.g., a rotation speed command value) to the servo amplifier 41 according to the control pattern provided by the control pattern selection unit 52. The pattern evaluation unit 54 obtains the power consumption measured by the power monitor 31, the time measured by the timer 55, and the number of molding cycles that can be determined from the start and end of the molding cycle provided by the sequence control unit 35 during the period when molding operations are performed based on the same control pattern, and calculates a productivity index. The timer 55 associates this productivity index with the control pattern and stores it in the memory unit 51.

[0043] Here, the productivity index includes the sum of the power consumption measured in the molding cycles repeatedly performed during a certain period of time, and at least one of the actual operation time when the predetermined number of molding cycles are performed and the number of molding cycles repeatedly performed during the certain period of time. That is, when the productivity index is first index information, the productivity index includes the sum of the power consumption measured in the predetermined number of molding cycles and the actual operation time when the predetermined number of molding cycles are performed. When the productivity index is second index information, the productivity index includes the sum of the power consumption measured in the molding cycles repeatedly performed during the certain period of time and the number of molding cycles repeatedly performed during the certain period of time. When the productivity index is third index information, the productivity index includes the sum of the power consumption measured in the predetermined number of molding cycles, the actual operation time when the predetermined number of molding cycles are performed, and the number of molding cycles repeatedly performed during the certain period of time. The actual operation time mentioned above is related to the increase in power consumption of other parts of the injection molding machine 10 and the number of molded products produced. Furthermore, the number of molding cycles is related to the number of molded products produced, and the number of products produced is directly linked to production profits.

[0044] The control pattern selection unit 52 in the first embodiment selects the control pattern that maximizes production profit by taking into consideration the profit amount per molded product and the electricity price in addition to the productivity index.

[0045] Next, we will explain the operation of the molding apparatus 1 having the hydraulic control device 33. Fig. 5 shows a flowchart explaining the operation of the molding apparatus 1 according to the first embodiment. In Fig. 5, n is the control pattern number, N is the number of control patterns prepared in advance, m is the number of molding cycles, and M is a cycle repetition setting value for repeating the molding cycle in the control pattern verification process.

[0046] As shown in FIG. 5, the molding apparatus 1 according to the first embodiment starts power monitoring and productivity index calculation when the hydraulic oil temperature reaches a manufacturer-recommended or predetermined set temperature through multiple molding cycles after molding begins. To perform the power monitoring and productivity index calculation, the control pattern number n is first initialized to 1 (step S0). The control pattern selection unit 52 then selects control pattern [1] and provides the selected control pattern [n] to the command value generation unit 53 (step S1). The hydraulic control device 33 then initializes the number of molding cycles m to 1 (step S2). The system control device 32 then instructs the molding apparatus 1 to perform the molding operation (step S3). After the molding operation in step S3 is completed, the control pattern selection unit 52 and the pattern evaluation unit 54 determine whether the number of molding cycles m matches a preset value M, which is a predetermined number of molding cycles to be repeated (step S4). Then, in step S4, the system control device 32 performs molding work while incrementing the number of molding cycles m by one (step S5) until the number of molding cycles m matches the cycle repetition set value M. The set value M may be a predetermined time.

[0047] The time measured by the pattern evaluation unit 54 is the time from the start to the end of the processing of steps S2 to S5. However, the time during which the molding operation is temporarily interrupted for a break or the like before the processing of steps S2 to S5 is completed, and the time during which the operation is interrupted when the processing of steps S2 to S5 is carried out across two days, may be excluded from the time to be measured. Furthermore, the power consumption measured by the pattern evaluation unit 54 may also exclude the power consumption during the period excluded from the measurement time.

[0048] Next, the pattern evaluation unit 54 calculates the productivity index when the molding operation is performed using the control pattern [n] (for example, during the period when the processes of steps S2 to S5 are being performed) (step S6). Then, the control pattern selection unit 52 determines whether the control pattern number n matches the control pattern number N (step S7). The hydraulic control device 33 repeats the processes of steps S1 to S8 while increasing the control pattern number n by one until the control pattern number n matches the control pattern number N (step S8). Then, after the control pattern number n matches the control pattern number N, the pattern evaluation unit 54 refers to the productivity indexes linked to each control pattern and switches to an operation for performing the molding operation in which the control pattern with the highest productivity index is selected. Note that in the first embodiment, the highest productivity index is the productivity index that maximizes production profit.

[0049] As explained above, the molding apparatus 1 according to the first embodiment generates a productivity index that serves as a criterion for determining productivity for each of a plurality of control patterns that have different motor control sequences. Then, the generated productivity index can be referenced to identify the control pattern that provides the highest productivity (for example, the highest production profit). This allows the molding apparatus 1 according to the first embodiment to easily operate with high productivity.

[0050] In the above explanation, the power monitor 31 is used to grasp the power consumption, but it is also possible to use a monitor device that measures only the current consumption or only the output voltage output by the AC power supply 30, and grasp the power consumption from the value acquired from the monitor device.

[0051] Embodiment 2 In the second embodiment, a hydraulic control device 33a will be described, which is another embodiment of the hydraulic control device 33. In the description of the second embodiment, the same components as those described in the first embodiment will be assigned the same reference numerals as in the first embodiment, and the description thereof will be omitted.

[0052] Fig. 6 shows a block diagram of a hydraulic control device 33a according to the second embodiment. In the example shown in Fig. 6, a system control device including the hydraulic control device 33a is shown as a system control device 32a. In addition, the hydraulic control device 33 according to the second embodiment has the control pattern selection unit 52 replaced with a control pattern selection unit 52a. The control pattern selection unit 52 has a function of transmitting a mode designated by a user from the display unit 34 as a mode selection instruction, and selecting an optimal control pattern in the mode designated by the mode selection instruction.

[0053] This mode includes, for example, the production profit priority mode described in the first embodiment. Furthermore, it is also conceivable to set, for example, a production volume priority mode or an energy efficiency priority mode in addition to the production profit priority mode. It is also conceivable that the production volume priority mode or the energy efficiency priority mode may be applied to the control pattern selection unit 52 of the first embodiment instead of the production profit priority mode. However, the control pattern selection unit 52a has at least one mode selected from the production profit priority mode, the production volume priority mode, and the energy efficiency priority mode for minimizing power consumption. Furthermore, in the first embodiment, at least two modes selected from the production profit priority mode, the production volume priority mode, and the energy efficiency priority mode for minimizing power consumption are provided, and the mode selected can be switched to the mode appropriate for the molding operation based on an external instruction.

[0054] The production volume priority mode is a mode in which the pump is controlled using a control pattern that maximizes the production volume per unit time. However, the upper limit of the operating pattern is limited by preventing overload and wear and tear on the equipment. The energy efficiency priority mode is a mode in which the pump is controlled using a control pattern that minimizes power consumption. However, even in the energy efficiency priority mode, processing of productivity indicators including time is not completely ignored; an upper limit is set for the time element. Furthermore, the optimal value for the energy efficiency priority mode does not exclude values ​​that are determined solely based on the energy efficiency of the oil feed pump 21, but it is desirable to determine the optimal value by taking into account the correlation with the increase in energy consumption of other parts of the molding apparatus 1 when the molding cycle time is extended by changing the control pattern of the oil feed pump 21.

[0055] It is also possible to provide various modes that pursue productivity indices that are subdivided according to the degree between the production volume priority mode, production profit priority mode, and energy efficiency priority mode, and to adjust the modes.As described above, by using the hydraulic control device 33a according to the second embodiment, it is possible to flexibly respond to efficiency improvements in terms of the molding quantity of molded products and energy efficiency.

[0056] Embodiment 3 In the third embodiment, a hydraulic control device 33b will be described, which is another embodiment of the hydraulic control device 33. In the description of the second embodiment, the same components as those described in the first embodiment will be assigned the same reference numerals as in the first embodiment, and the description thereof will be omitted.

[0057] FIG. 7 shows a block diagram of a hydraulic control device 33b according to the third embodiment. In the example shown in FIG. 7, a system control device including the hydraulic control device 33b is shown as a system control device 32b. Furthermore, the molding apparatus 1 according to the third embodiment has an oil feed pump 21b instead of the oil feed pump 21. The oil feed pump 21b is obtained by adding a motor control unit 44 to the oil feed pump 21. The motor control unit 44 uses, for example, AI (Artificial Intelligence) technology to issue an operation instruction to the servo amplifier 41 so as to minimize the power consumption of the oil feed pump 21b while satisfying the request given by the hydraulic control device 33b (for example, the oil pressure realized based on the rotation speed command value). The above can also be realized by an edge AI attached to the oil feed pump 21b.

[0058] However, even if the power consumption of the oil feed pump 21b alone can be reduced, the power consumption of other parts of the molding apparatus 1 may increase due to reasons such as an extension of the molding time. Therefore, in the hydraulic control device 33b according to the third embodiment, when the power consumption obtained from the power monitor 31 included in the molding apparatus 1 indicates an increasing trend, the hydraulic control device 33b corrects the control pattern so that the power consumption will tend to decrease, and issues a request to the motor control unit 44. An example of the configuration of the hydraulic control device 33b for performing such an operation is shown in FIG. 7.

[0059] 7, the hydraulic control device 33b is obtained by adding a command value correction instructing unit 56 to the hydraulic control device 33 and replacing the command value generating unit 53 with a command value generating unit 53b. When the power consumption obtained from the power monitor 31 indicates an increasing trend, the command value correction instructing unit 56 calculates a correction amount for the rotation speed command value for the servo motor 42 that drives the pump mechanism 43 at each stage in accordance with a predetermined rule and transmits the correction amount to the command value generating unit 53b. The command value generating unit 53b corrects the rotation speed instructed by the control pattern with the correction amount provided by the command value correction instructing unit 56 and then provides the rotation speed command value to the motor control unit 44.

[0060] From the above explanation, in the molding apparatus 1 having the hydraulic control device 33b according to the third embodiment, even if the power consumption of the entire molding apparatus increases due to the power saving control of the oil feed pump 21b, it is possible to suppress the power consumption of the entire molding apparatus.

[0061] The present invention is not limited to the above-described embodiments, and modifications and combinations of examples are possible without departing from the spirit and scope of the present invention. The present invention is not limited to any particular pump type, and may include a vane pump, gear pump, piston pump (including an axial piston pump), screw pump, plunger pump, or the like. The pump may have a fixed discharge volume per revolution or a variable discharge volume. Furthermore, the motor driving the pump is not limited to a servomotor, as long as its rotation speed can be controlled and varied. While the first to third embodiments describe an example in which a single pump is provided, the molding apparatus may also be equipped with multiple pumps of the same or different capacities. In this case, multiple pumps may be provided, and at least one pump may be operated only when a large amount of hydraulic oil is required, such as for moving or pressurizing the clamping cylinder during mold clamping. When controlling the number of pumps, each pump is provided with its own control pattern. Combining these control patterns often results in a large number of control patterns. Therefore, it is preferable to use a machine learning device to select the optimal control pattern using a rule-based or other learning model.

[0062] Furthermore, the fluidity of the hydraulic oil used in the injection device 1 varies depending on the temperature and degree of deterioration of the hydraulic oil, and the efficiency of the pump also varies. Therefore, the pump may be operated based on a control pattern selected from multiple control patterns for each hydraulic oil temperature, and a control pattern verification process may be pursued to optimize the productivity index. Furthermore, even after an optimal control pattern for the pump has been created, the process for verifying the optimal control pattern for the pump may be performed again as the hydraulic oil deteriorates. [Explanation of symbols]

[0063] 1 Molding equipment 10 injection molding machine 11 Fixed plate 12 Movable plate 13 Tie bar 14 Mold 15 Molds 16 Injection nozzle 17 Movable platen movement mechanism 18 Half nut lock mechanism 19 Mold clamping cylinder 20 Oil storage tank 21 Oil pump 22 Check valve 23 Pressure Control Valve 24 Directional Control Valve 30 AC power supply 31 Power Monitor 32 System Control Unit 33 Hydraulic control device 34 Display section 35 Sequence control section 41 Servo amplifier 42 Servo motor 43 Pump mechanism 44 Motor control unit 51 Storage section 52 Control pattern selection section 53 Command value generation unit 54 Pattern Evaluation Section 55 Timer 56 Command value correction instruction section

Claims

1. A molding device including a hydraulic mechanism that drives a mechanism by hydraulic pressure, At least one pump having a motor with a variable rotation speed; a hydraulic control device that controls the motor based on one control pattern selected from a plurality of control patterns for the motor stored in a storage unit to control the hydraulic pressure; a power monitor that measures power consumption by at least the motor; The hydraulic control device includes: a power monitor process for performing a molding cycle in which the pump is controlled based on the control pattern and measuring the power consumption during the molding cycle by the power monitor; a productivity index calculation process for calculating a productivity index including at least the power consumption during the molding cycle and the time required for the molding cycle; a control pattern verification process for performing the power monitoring process and the productivity index calculation process for each of the plurality of control patterns;

2. 2. The molding apparatus according to claim 1, wherein the productivity index includes the sum of the power consumption measured in the molding cycles repeatedly performed during a certain period of time, and at least one of the actual working time when the molding cycles are performed a predetermined number of times and the number of molding cycles repeatedly performed during the certain period of time.

3. the pump has a motor control unit that controls the motor so as to satisfy the requirements from the hydraulic control device and minimize the power consumption of the motor, The molding device described in claim 1, wherein when the power consumption obtained from the power monitor included in the molding device shows an increasing trend, the hydraulic control device corrects the control pattern so that the power consumption shows a decreasing trend and makes a request to the motor control unit.

4. The hydraulic control device includes: a production volume priority mode in which the pump is controlled using the control pattern that maximizes the production volume per unit time; a production profit priority mode in which the pump is controlled using the control pattern that maximizes the production profit per product calculated based on the production quantity per unit time and the power consumption; an energy efficiency priority mode in which the pump is controlled using the control pattern that minimizes the power consumption; 2. The molding apparatus according to claim 1, having at least one of the following modes:

5. The molding device according to claim 4, wherein the hydraulic control device has at least two modes: the production volume priority mode, the production profit priority mode, and the energy efficiency priority mode, and switches the mode applied to the molding operation based on an external instruction.

6. The molding apparatus according to claim 1 , wherein the control pattern is a rotation speed control pattern that indicates the rotation speed of the motor.

7. A control method for a molding apparatus including a hydraulic mechanism that drives a mechanism by hydraulic pressure, the control method including: at least one pump equipped with a motor whose rotation speed is variable; a hydraulic control device that controls the motor based on one control pattern selected from a plurality of control patterns for the motor stored in a storage unit to control the hydraulic pressure; and a power monitor that measures at least the power consumed by the motor, The hydraulic control device a power monitor process for performing a molding cycle in which the pump is controlled based on the control pattern and measuring the power consumption during the molding cycle by the power monitor; a productivity index calculation process for calculating a productivity index including at least the power consumption during the molding cycle and the time required for the molding cycle; a control pattern verification process for performing the power monitoring process and the productivity index calculation process for each of the plurality of control patterns;

8. A molding apparatus including a hydraulic mechanism that drives a mechanism by hydraulic pressure, the hydraulic mechanism including at least one pump equipped with a motor whose rotation speed can be changed, a hydraulic control device that controls the motor based on one control pattern selected from a plurality of control patterns for the motor stored in a storage unit to control the hydraulic pressure, and a power monitor that measures at least the power consumed by the motor, the hydraulic control device comprising: a control program executed by a calculation unit in the hydraulic control device; a power monitor process for performing a molding cycle in which the pump is controlled based on the control pattern and measuring the power consumption during the molding cycle by the power monitor; a productivity index calculation process for calculating a productivity index including at least the power consumption during the molding cycle and the time required for the molding cycle; a control program for a molding device that performs a control pattern verification process in which the power monitoring process and the productivity index calculation process are performed for each of the plurality of control patterns;

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