Injection molding system, oil temperature control program, and oil temperature control method

Abstract

To provide a solution to a problem with a conventional injection molding system in that the temperature raising operation cannot be optimized in response to changes in operating conditions such as oil temperature, environmental temperature, and idle time of an injection molding machine before temperature raising starts.SOLUTION: An injection molding system according to an embodiment of the present invention comprises: an oil distribution channel; an oil storage tank for storing a hydraulic oil used in a hydraulic cylinder; a hydraulic oil temperature raising mechanism for raising the temperature of the hydraulic oil in the oil storage tank; and a control device for controlling each of a drive mechanism for driving the hydraulic cylinder and a hydraulic oil temperature raising mechanism. The control device sets a heating target temperature defined as a parameter that can be set to an arbitrary value in a temperature range equal to or higher than an operation start temperature, and performs a temperature raising operation of the hydraulic oil with the heating target temperature as the upper limit at least before continuous operation.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] Some injection molding machines use a hydraulic mechanism to generate a pressure force. Such hydraulic mechanisms move a piston by supplying hydraulic oil to a cylinder, but in order for the hydraulic mechanism to function properly, it is required that the hydraulic oil be used within a certain temperature range. Therefore, in injection molding machines having a hydraulic mechanism, the temperature of the hydraulic oil is raised to a predetermined temperature range before starting continuous operation. An example of such a technique is disclosed in Patent Document 1.

[0003] The hydraulic oil heating method described in Patent Document 1 is a hydraulic oil heating method for a molding machine in which, when operating a hydraulic drive unit equipped with a hydraulic pump that is rotationally driven by a drive motor, the hydraulic pump is operated when the temperature of the hydraulic oil is lower than a target temperature, and the hydraulic oil discharged from the hydraulic pump is passed through a specific flow path section that has a greater flow resistance than at least the oil distribution pipe section, thereby generating heat and raising the temperature of the hydraulic oil.The method is characterized in that, as the hydraulic pump, a variable discharge type hydraulic pump is used that can control at least the discharge flow rate of the hydraulic oil by variably controlling the rotation speed of the drive motor, and a target load amount is set for the drive motor in advance, and the rotation speed of the drive motor is variably controlled so that the load amount of the drive motor becomes the target load amount when the temperature of the hydraulic oil reaches the target temperature. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-126107 A Summary of the Invention [Problem to be solved by the invention]

[0005] The hydraulic oil temperature increasing method described in Patent Document 1 is capable of increasing the temperature of the hydraulic oil, but has a problem in that it is not possible to optimize the temperature increasing operation in response to changes in operating conditions such as the oil temperature before the start of the temperature increase, the environmental temperature, and the downtime of the injection molding machine.

[0006] The present invention has been made in consideration of the above circumstances, and aims to optimize the hydraulic oil temperature raising process performed at least before continuous operation in an injection molding system, regardless of the operating conditions. Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0007] An injection molding system according to one embodiment includes an oil distribution flow path including a hydraulic cylinder and a hydraulic oil path between the hydraulic cylinder and an oil storage tank, an oil storage tank for storing hydraulic oil used in the hydraulic cylinder, a hydraulic oil heating mechanism for heating the temperature of the hydraulic oil in the oil storage tank, and a control device for controlling each of a drive mechanism for driving the hydraulic cylinder and the hydraulic oil heating mechanism, wherein a heating target temperature is set in the control device, the heating target temperature being defined as a parameter that can be set to any value within a temperature range equal to or higher than an operation start temperature, and during a preparation period before the hydraulic cylinder is operated continuously, The system performs a temperature rise instruction process that instructs the hydraulic oil heating mechanism to perform a heating operation to heat the hydraulic oil stored in the oil storage tank to the heating target temperature, a dry operation instruction process that instructs the drive mechanism to perform a dry operation to mix the hydraulic oil held in the oil distribution flow path with the hydraulic oil in the oil storage tank, and a re-heating loop instruction process that instructs the hydraulic oil heating mechanism and the drive mechanism to perform at least the heating operation of the heating operation and the dry operation when the temperature of the hydraulic oil in the oil storage tank after the dry operation is lower than a predetermined operation start temperature.

[0008] A temperature increase control program according to one embodiment is an oil temperature control program executed by a processor in a control device in an injection molding system having a hydraulic cylinder, an oil distribution flow path including a hydraulic oil path between the hydraulic cylinder and an oil storage tank, an oil storage tank for storing hydraulic oil used in the hydraulic cylinder, a hydraulic oil heating mechanism for heating the temperature of the hydraulic oil in the oil storage tank, and a control device for controlling each of a drive mechanism for driving the hydraulic cylinder and the hydraulic oil heating mechanism, the oil temperature control program being configured to include a heating target temperature defined as a parameter that can be set to any value within a temperature range equal to or higher than an operation start temperature, During a preparation period before the hydraulic cylinder is operated continuously, a temperature increase instruction process is performed to instruct the hydraulic oil temperature increase mechanism to perform a temperature increase operation to increase the temperature of the hydraulic oil stored in the oil storage tank to the heating target temperature, a dry operation instruction process is performed to instruct the drive mechanism to perform a dry operation to mix the hydraulic oil held in the oil distribution flow path with the hydraulic oil in the oil storage tank, and a re-heating loop instruction process is performed to instruct the hydraulic oil temperature increase mechanism and the drive mechanism to perform at least the temperature increase operation of the temperature increase operation and the dry operation when the temperature of the hydraulic oil in the oil storage tank after the dry operation is lower than a predetermined operation start temperature.

[0009] A temperature rise control method according to one embodiment is an oil temperature control method for controlling the temperature rise of the hydraulic oil using a computer in an injection molding system having an oil distribution flow path including a hydraulic cylinder and a hydraulic oil path between the hydraulic cylinder and an oil storage tank, an oil storage tank for storing the hydraulic oil used in the hydraulic cylinder, a hydraulic oil heating mechanism for adjusting the temperature of the hydraulic oil in the oil storage tank, and a control device for controlling each of a drive mechanism for driving the hydraulic cylinder and the hydraulic oil heating mechanism, the method defining a heating target temperature as a parameter that can be set to an arbitrary value within a temperature range equal to or higher than an operation start temperature, and During a preparation period before the start of operation, the computer is caused to perform a temperature increase instruction process that instructs the hydraulic oil heating mechanism to perform a heating operation to heat the hydraulic oil stored in the oil storage tank to the heating target temperature, a dry operation instruction process that instructs the drive mechanism to perform a dry operation to mix the hydraulic oil held in the oil distribution flow path with the hydraulic oil in the oil storage tank, and a re-heating loop instruction process that instructs the hydraulic oil heating mechanism and the drive mechanism to perform at least the heating operation of the heating operation and the dry operation when the temperature of the hydraulic oil in the oil storage tank after the dry operation is lower than a predetermined operation start temperature.

[0010] In the injection molding system, oil temperature control program, and oil temperature control method according to one embodiment, the heating target temperature is defined as a parameter that can be set to any value within a temperature range above the operation start temperature, and a heating operation corresponding to this heating target temperature is performed. Effect of the Invention

[0011] According to the injection molding system, the oil temperature control program, and the oil temperature control method according to one embodiment, at least the hydraulic oil temperature raising process performed before continuous operation in the injection molding system can be optimized regardless of the operating conditions. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a configuration diagram for explaining an outline of an injection molding system according to a first embodiment. [Diagram 2] 4 is a flowchart illustrating a flow of a hydraulic oil temperature increasing step performed before a continuous operation in the injection molding system according to the first embodiment. [Diagram 3] 5 is a timing chart illustrating the operation of a first example of a hydraulic oil temperature increasing step performed before a continuous operation in the injection molding system according to the first embodiment. [Figure 4] 6 is a timing chart illustrating the operation of a second example of a hydraulic oil temperature increasing step performed before a continuous operation in the injection molding system according to the first embodiment. [Diagram 5] 13 is a timing chart illustrating the operation of a third example of a hydraulic oil temperature increasing step performed before a continuous operation in the injection molding system according to the first embodiment. [Figure 6] 13 is a flowchart illustrating a first example of the flow of a hydraulic oil temperature increasing step performed before a continuous operation in the injection molding system according to the second embodiment. [Figure 7] 10 is a timing chart illustrating the operation of a first example of a hydraulic oil temperature increasing step performed before a continuous operation in the injection molding system according to the second embodiment. [Figure 8] 13 is a flowchart illustrating a second example of the flow of a hydraulic oil temperature increasing step performed before a continuous operation in the injection molding system according to the second embodiment. [Figure 9] 13 is a timing chart illustrating the operation of a second example of a hydraulic oil temperature increasing step performed before a continuous operation in the injection molding system according to the second embodiment. [Figure 10] 13 is a flowchart illustrating the flow of a first example of a temperature rise start condition determination process in the injection molding system according to the third embodiment. [Figure 11] 13 is a flowchart illustrating a flow of a second example of a temperature rise start condition determination process in the injection molding system according to the third embodiment. [Figure 12] 13 is a flowchart illustrating a flow of a third example of a temperature rise start condition determination process in the injection molding system according to the third embodiment. [Figure 13]13 is a flowchart illustrating the flow of a hydraulic oil temperature increasing step performed before a continuous operation in the injection molding system according to the fourth embodiment. [Figure 14] 4 is a timing chart illustrating a temperature increase schedule in the injection molding system according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] In order to clarify the description, the following description and drawings are omitted and simplified as appropriate. In addition, 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, can be realized by a program loaded into memory. Therefore, it is understood by those skilled in the art that these functional blocks can be realized in various forms by hardware alone, software alone, or a combination thereof, and are not limited to any one of them. In addition, the same elements are given the same symbols in each drawing, and duplicated explanations are omitted as necessary.

[0014] Moreover, the above-mentioned program includes a set of instructions (or software code) for making the computer perform one or more functions described in the embodiment when the program is read into the computer. The program may be stored in a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, the computer-readable medium or the tangible storage medium includes 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) disk or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The program may be transmitted on a transitory computer-readable medium or a communication medium. By way of example and not limitation, the transitory computer-readable medium or the communication medium includes electrical, optical, acoustic, or other forms of propagating signals.

[0015] First embodiment Fig. 1 shows a configuration diagram for explaining an outline of an injection molding system 1 according to the first embodiment. As shown in Fig. 1, the injection molding system 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, a cross section of a part that cannot be seen from the outside of the injection molding machine 10 is shown within a hatched area.

[0016] As shown in Fig. 1, an injection molding machine 10 includes a fixed platen 11, a movable platen 12, tie bars 13, molds 14 and 15, an injection nozzle 16, a movable platen moving mechanism 17, a half nut lock mechanism 18, and a mold clamping cylinder 19. The components of the injection molding machine 10 shown in Fig. 1 are the main components of the injection molding machine 10, and the illustrated components may be included. Furthermore, the molds 14 and 15 are often not included in the injection molding machine 10 at the distribution stage.

[0017] The fixed platen 11 is fixed to a base, and the mold 15 is removably fixed thereto. In the example shown in Fig. 1, a hole through which the injection nozzle 16 is inserted is formed in the fixed platen 11, and the injection nozzle 16 can abut against a nozzle touch portion of the fixed mold 14 through the hole in the fixed platen 11. The injection nozzle 16 is configured to inject resin through the nozzle touch hole toward a cavity formed between the mold 14 and the mold 15. The injection nozzle 16 is configured to move back and forth by, for example, a nozzle touch cylinder (not shown). The fixed platen 11 is also provided with a mold clamping cylinder 19.

[0018] The tie bars 13 are provided at the four corners of the fixed platen 11. Furthermore, the movable platen 12 has insertion holes at its four corners, through which the tie bars 13 are inserted, and the tie bars 13 are inserted into the 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 a half nut that fits into a groove engraved in the tie bar 13, and the half nut is fitted into the groove of the tie bar 13 to substantially integrate the movable platen 12 with the tie bar 13.

[0019] Here, in the example shown in Fig. 1, the mold clamping cylinder 19 is a hydraulic cylinder. The mold 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 mold clamping direction) to move the tie bar 13 in the mold 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 in 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. Also, for the movable platen moving mechanism 17, a hydraulic cylinder may be used instead of an electric mechanism.

[0020] In this way, many hydraulic cylinders that operate various parts by hydraulic pressure are incorporated in the injection molding machine 10. Hydraulic oil is used to drive these hydraulic cylinders. In the injection molding system 1 according to the first embodiment, many pipes are provided to supply and discharge this hydraulic oil to and from the hydraulic cylinders in the injection molding machine 10.

[0021] The injection molding system 1 according to the first embodiment supplies and recovers hydraulic oil, and has a configuration for managing the temperature of the hydraulic oil. Specifically, the injection molding system 1 according to the first embodiment has an oil distribution flow path, an oil storage tank 20, a hydraulic oil heating mechanism 21, a control device 22, and an oil temperature sensor 23 in addition to the injection molding machine 10. Although not shown, the injection molding machine 10 also has an oil cooler for keeping the temperature of the hydraulic oil during operation from rising above a temperature to be maintained during continuous molding.

[0022] 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. This hydraulic oil path includes piping that serves as a hydraulic oil flow path, valves on the piping, various devices on the path through which the hydraulic oil flows, such as a pump 31, etc.

[0023] The hydraulic oil temperature raising mechanism 21 stores hydraulic oil used in the hydraulic cylinder. The control device 22 controls both the drive mechanism that drives the hydraulic cylinder and the hydraulic oil temperature raising mechanism 21. The drive mechanism includes a pump 31 that sends the hydraulic oil to piping and pressurizes the hydraulic oil, and valves that switch the flow path of the hydraulic oil and control the pressure. The control device 22 also measures the temperature of the hydraulic oil stored in the oil storage tank 20 using an oil temperature sensor 23. The functions of the control device 22 will be described in more detail later.

[0024] Here, the piping for hydraulic oil, which is a part of the oil distribution flow path, and the valves and pump 31 arranged on the piping will be described in detail. As shown in FIG. 1, in the injection molding system 1 according to the first embodiment, piping is provided to connect the oil storage tank 20 and the plurality of hydraulic cylinders, respectively. The piping is provided with a plurality of valves for switching the path through which the hydraulic oil flows and for controlling the flow rate of the hydraulic oil, and at least one pump 31 for pressurizing the hydraulic oil. In the example shown in FIG. 1, the pump 31, the directional control valve 32, the relief valve 33, the check valve 34, the pressure control valve 35, and the directional control valve 36 are shown on the piping that is the path for the hydraulic oil. Note that the directional control valve 32 is not essential.

[0025] The pump 31 delivers the hydraulic oil stored in the oil storage tank 20 to the hydraulic cylinder side. The directional control valve 32 and the relief valve 33 are provided on a path that circulates the hydraulic oil in the oil storage tank 20 through a flow path separate from the oil distribution flow path. The directional control valve 32 switches whether or not to deliver at least a part of the hydraulic oil delivered from the pump 31 to the relief valve 33. The relief valve 33 has a function of preventing the pressure of the piping connected to the primary side from exceeding a certain level by delivering the hydraulic oil to the secondary side when the pressure of the piping on the primary side of the valve exceeds a certain level. The set pressure for the relief valve 33 to flow the hydraulic oil in the primary piping to the secondary side can be adjusted by the control device 22 described later. In addition, the injection molding system 1 uses the mechanisms of the pump 31 and the relief valve 33 to heat the hydraulic oil, which will be described in detail later.

[0026] The check valve 34 is a check valve that prevents hydraulic oil discharged from the pump 31 from flowing back from the cylinder side to the pump 31 side. The pressure control valve 35 is provided closer to the hydraulic cylinder than the check valve 34, and controls the pressure of the hydraulic oil in the piping on the cylinder side. The directional control valve 36 switches between sending and discharging the hydraulic oil to the hydraulic cylinder. Although only the directional control valve 36 provided for the illustrated mold clamping cylinder 19 is shown in FIG. 1, the directional control valve 36 is provided for each of the multiple cylinders. The flow path of the hydraulic oil is switched by the directional control valve 36 by the control device 22. It is possible to control the supply of hydraulic oil to the hydraulic cylinder by using a cartridge valve or the like instead of the directional control valve 36.

[0027] In the injection molding system 1 according to the first embodiment, the hydraulic oil heating mechanism 21 is configured with a pump 31, a directional control valve 32, and a relief valve 33. The pump 31 included in the hydraulic oil heating mechanism 21 also functions as a drive mechanism for driving the clamping cylinder 19. In other words, the pump 31 is shared by both the drive mechanism and the hydraulic oil heating mechanism 21.

[0028] In the hydraulic oil temperature raising mechanism 21 using the relief valve 33, the pump 31 raises the pressure of the hydraulic oil in the primary piping of the relief valve 33 to a set pressure or higher, and when the relief valve 33 opens, the hydraulic oil is heated by frictional heat when passing through the narrow passage of the valve, thereby raising the temperature of the hydraulic oil stored in the oil storage tank 20. When performing the temperature raising operation by the hydraulic oil temperature raising mechanism 21, the control device 22 issues an operation instruction to the pump 31 and controls the set pressure of the relief valve 33. At this time, the set pressure of the relief valve 33 may be variably controlled. As an example, the set pressure of the relief valve 33 may be lowered for a predetermined time from the start of rotation of the pump 31 and then raised after a certain time, or the set pressure of the relief valve 33 may be lowered while the temperature of the hydraulic oil is below a certain temperature and then raised when the temperature of the hydraulic oil becomes higher than the certain temperature.

[0029] 1, a relief valve 33 is used as the hydraulic oil temperature raising mechanism 21, but a heater that raises the temperature of the hydraulic oil in the oil storage tank or the hydraulic oil path may be used as the hydraulic oil temperature raising mechanism 21. Examples of the heater include a cartridge heater that directly heats the hydraulic oil stored in the oil storage tank 20, an induction heating device (induction heater) in which a heater is wrapped around a pipe, and a heating device that passes a heat medium pipe through the oil storage tank 20 and raises the temperature of the hydraulic oil, which is provided separately from the oil storage tank.

[0030] One of the features of the injection molding system 1 according to the first embodiment is the method of controlling the temperature rise of the hydraulic oil by the control device 22. The control device 22 may be dedicated hardware that realizes the control method described below, or may be a computer having a calculation unit that executes an oil temperature management program. Therefore, the control device 22 of the injection molding system 1 may be a device other than that attached to the injection molding machine 10.

[0031] The control device 22 has, as parameters for controlling the temperature of the hydraulic oil, an operation start temperature Top and a heating target temperature Tt shown in Fig. 3. These parameters may be values ​​stored in a memory in the control device 22, or may be values ​​input to the control device 22 by an operator.

[0032] In the control device 22, a heating target temperature Tt is set, which is defined as a parameter that can be set to any value within a temperature range equal to or higher than the operation start temperature Top. Here, the operation start temperature Top is a temperature at which the injection molding machine 10 can be operated continuously when the oil temperature control program of this embodiment is executed. The control device 22 performs temperature management of the hydraulic oil so that the temperature of the hydraulic oil is maintained within a predetermined temperature range with respect to the operation start temperature Top during the period in which the injection molding machine 10 is operated continuously.

[0033] The operation start temperature Top is a temperature designated by regulations set by the hydraulic oil supplier, the injection molding system 1 supplier, and the factory that uses the injection molding machine 10, and is a temperature for making hydraulic mechanisms such as hydraulic cylinders function efficiently with the hydraulic oil. The heating target temperature Tt is set with the recommended use temperature designated by regulations set by the hydraulic oil supplier, the injection molding machine 10 supplier, and the factory that uses the injection molding machine 10 as its upper limit. This recommended use temperature is a temperature intended to suppress the deterioration of the hydraulic oil. The operation start temperature Top may be the same temperature as the maintenance temperature during continuous molding, or may be set to a temperature lower than the maintenance temperature in anticipation of the temperature rise of the hydraulic oil during continuous molding.

[0034] The heating target temperature Tt is set as an arbitrary value, and the setting method can be one of the first to third examples. In the first example, the supplier of the injection molding system 1 sets the temperature as an arbitrary fixed value before the shipment of the injection molding system 1. In the second example, the customer can change the temperature to an arbitrary value according to the hydraulic oil and air temperature conditions after the shipment of the injection molding system 1. In the third example, the control device 22 automatically changes the temperature to an arbitrary value according to the hydraulic oil temperature detected by the oil temperature sensor 23. In the explanation of the first embodiment, an example will be explained in which the heating target temperature Tt is set according to the first to third examples and is maintained constant at least during the period of the hydraulic oil temperature increase step before the start of continuous operation.

[0035] In the injection molding system 1 according to the first embodiment, a pre-continuous operation hydraulic oil heating step is performed in a preparation period before the injection molding machine 10 including the hydraulic cylinder is continuously operated. In the pre-continuous operation hydraulic oil heating step, the control device 22 operates the hydraulic oil heating mechanism 21 and the drive mechanism that drives the hydraulic cylinder, thereby efficiently heating the hydraulic oil to a temperature equal to or higher than the operation start temperature.

[0036] In the hydraulic oil heating process before continuous operation, the control device 22 performs a temperature increase instruction process, a dry operation instruction process, and a re-heating loop instruction process. In the temperature increase instruction process, an instruction is given to the hydraulic oil heating mechanism to perform a heating operation to heat the hydraulic oil stored in the oil storage tank 20 to the heating target temperature Tt.

[0037] In the dry operation instruction process, an instruction is given to the drive mechanism to perform dry operation in which the hydraulic oil held in the oil distribution passage is mixed with the hydraulic oil in the oil storage tank 20. In this dry operation, the hydraulic cylinder provided in the injection molding machine 10 is driven to return the hydraulic oil that has not been sufficiently heated in the hydraulic cylinder and the oil distribution passage to the oil storage tank 20. In the dry operation, the hydraulic cylinder is moved, and although it is not impossible to perform this in a state in which the half nuts of the half nut lock mechanism 18 are engaged with the tie bar 13 in the injection molding machine 10, it is preferable to perform this with the half nuts in an unengaged state with the tie bar 13. By performing the dry operation with the half nuts in an unengaged state with the tie bar 13, dry operation without movement of the movable platen 12 is possible. Therefore, the dry operation in this invention does not only refer to a dry operation of a molding cycle in which resin is not injected from the injection device, but rather refers to an operation in which the piston of a hydraulic cylinder such as the clamping cylinder 19 is moved back and forth within its stroke range to mix the hydraulic oil held in the oil distribution flow path including the clamping cylinder 19 with the hydraulic oil in the oil storage tank 20.

[0038] Although there are many restrictions on performing dry operation involving opening and closing of the movable platen 12 of the injection molding machine 10 in an unmanned factory, such as at night, the tolerance for operating the injection molding machine 10 in an unmanned state is increased by, for example, locking the movable platen moving mechanism 17 and keeping the movable platen 12 and the mold 15 stationary, and operating the clamping cylinder 19, tie bar 13, pump 31, and other parts in a limited manner, as in embodiment 1. Furthermore, it is also desirable to use a combination of a safety mat and a photocell that detects the intrusion of a worker into the operating area of ​​the injection molding machine 10 in order to increase the tolerance for operating the movable parts of the injection molding machine 10.

[0039] In the re-heating loop instruction process, when the temperature of the hydraulic oil in the oil storage tank 20 after dry operation is lower than a preset operation start temperature Top, an instruction is given to the hydraulic oil temperature raising mechanism and the drive mechanism to perform at least the temperature raising operation out of the temperature raising operation and the dry operation. Note that, when only the temperature raising operation is to be performed as a result of the re-heating loop instruction process, the control device 22 instructs the hydraulic oil temperature raising mechanism to perform the temperature raising operation and instructs the drive mechanism not to perform the operation.

[0040] The above-mentioned operation will be described with reference to a flowchart. Fig. 2 shows a flowchart for explaining the flow of the hydraulic oil temperature increasing step performed before the continuous operation in the injection molding system according to the first embodiment.

[0041] 2, when the pre-continuous operation hydraulic oil temperature raising process is started, the control device 22 first reads the heating target temperature Tt and the operation start temperature Top (step S1). The parameter reading process in step S1 may be, for example, a process in which the control device 22 loads the heating target temperature Tt and the operation start temperature Top from a memory, or a process in which an operator inputs the heating target temperature Tt and the operation start temperature Top to the control device 22.

[0042] Thereafter, the control device 22 performs a temperature increase instruction process to instruct the hydraulic oil temperature increase mechanism 21 to perform a temperature increase operation to increase the temperature of the hydraulic oil stored in the oil storage tank 20 to the heating target temperature Tt (steps S2, S3).

[0043] After the hydraulic oil in the oil storage tank 20 reaches the heating target temperature Tt, the control device 22 performs a dry operation instruction process to instruct the drive mechanism to perform a dry operation in which the hydraulic oil held in the oil distribution flow path is mixed with the hydraulic oil in the oil storage tank 20 (step S4). This dry operation may move the piston of a hydraulic cylinder such as the mold clamping cylinder 19 one-way stroke from one end of the cylinder chamber to the other end, a reciprocating stroke, or even multiple reciprocating strokes. The dry operation may be performed for a period of a predetermined length, or may be performed until the temperature of the hydraulic oil in the oil storage tank 20 drops. The dry operation may be performed simultaneously for each mold clamping cylinder 19, or may be performed individually and sequentially for each mold clamping cylinder 19.

[0044] After the dry operation (step S4) is completed, the control device 22 measures the temperature To of the hydraulic oil in the oil storage tank 20, and if the temperature To has not reached the preset operation start temperature Top, performs a re-heating loop instruction process that instructs the hydraulic oil heating mechanism 21 and the drive mechanism to perform a heating operation and dry operation (step S5). On the other hand, the control device 22 measures the temperature To of the hydraulic oil in the oil storage tank 20, and if the temperature To has reached the preset operation start temperature Top, ends the hydraulic oil heating process before continuous operation.

[0045] Next, the hydraulic oil temperature raising process before continuous operation of the injection molding system 1 according to the first embodiment will be described using a timing chart. In the following description, three examples of the hydraulic oil temperature raising process before continuous operation of the injection molding system 1 according to the first embodiment will be described. FIG. 3 is a timing chart for explaining the operation of a first example of the hydraulic oil temperature raising process performed before continuous operation in the injection molding system according to the first embodiment. The first example in FIG. 3 explains the operation of the hydraulic oil temperature raising process before continuous operation of the injection molding system 1 when the continuous operation of the injection molding system 1 has been stopped for a long time and the temperature of the hydraulic oil has dropped significantly compared to the operation start temperature Top.

[0046] In the first example shown in FIG. 3, when the hydraulic oil heating process before continuous operation is started, a heating operation is performed by the hydraulic oil heating mechanism 21 to heat the hydraulic oil in the oil storage tank 20 until the temperature of the hydraulic oil reaches the heating target temperature Tt. Then, when the temperature of the hydraulic oil reaches the heating target temperature Tt at timing T1, the heating operation to heat the hydraulic oil in the oil storage tank 20 is stopped, and dry operation is started. As a result, the relatively low-temperature hydraulic oil stored in the mold clamping side oil chamber and mold opening side oil chamber of the mold clamping cylinder 19 and the oil distribution flow path is returned to the oil storage tank 20 side through valves such as the directional control valve 36 and the return side oil distribution flow path, and the temperature of the hydraulic oil in the oil storage tank 20 is reduced. After that, since the temperature of the hydraulic oil in the oil storage tank 20 at the time when the dry operation is ended at timing T2 is lower than the operation start temperature Top, a heating operation to heat the hydraulic oil in the oil storage tank 20 is performed again. Then, when the temperature of the hydraulic oil reaches the heating target temperature Tt at timing T3, the temperature raising operation for raising the temperature of the hydraulic oil in the oil storage tank 20 is stopped, and dry operation is started. This causes the temperature of the hydraulic oil in the oil storage tank 20 to drop. After that, since the temperature of the hydraulic oil in the oil storage tank 20 at the time when the dry operation is ended at timing T4 is lower than the operation start temperature Top, the temperature raising operation for raising the temperature of the hydraulic oil in the oil storage tank 20 is performed again. Then, when the temperature of the hydraulic oil reaches the heating target temperature Tt at timing T5, the temperature raising operation for raising the temperature of the hydraulic oil in the oil storage tank 20 is stopped, and dry operation is started. This causes the temperature of the hydraulic oil in the oil storage tank 20 to drop. After that, since the temperature of the hydraulic oil in the oil storage tank 20 at the time when the dry operation is ended at timing T6 is higher than the operation start temperature Top, the control device 22 ends the hydraulic oil heating process before continuous operation. Then, at the start of molding, the operator operates the injection molding machine 10 by manual molding, and after performing the dry operation of the molding cycle or trial molding in which resin is injected, continuous operation is started. Alternatively, the continuous operation is started immediately after the completion of the hydraulic oil temperature raising process before the continuous operation. Therefore, at least the hydraulic oil temperature raising process needs to be completed before the continuous operation is started.

[0047] Next, FIG. 4 shows a timing chart for explaining the operation of a second example of the hydraulic oil heating process performed before the continuous operation in the injection molding system according to the first embodiment. The second example in FIG. 4 explains the operation of the hydraulic oil heating process before the continuous operation of the injection molding system 1 when the time during which the continuous operation of the injection molding system 1 is stopped is short and the amount of decrease in the temperature of the hydraulic oil relative to the operation start temperature Top is small. In the example shown in FIG. 4, the heating target temperature Tt is set to a temperature lower than that in the example shown in FIG. 3. In the second example shown in FIG. 4, the temperature of the hydraulic oil is higher than the operation start temperature Top by only performing one cycle of the heating operation and the dry operation. In this way, by arbitrarily setting the heating target temperature Tt to a low value according to the hydraulic oil in the oil storage tank 20 at the time of starting the hydraulic oil heating process before the continuous operation, the temperature of the hydraulic oil can be brought closer to the operation start temperature Top, while shortening the time required for heating and reducing the energy consumed.

[0048] Next, FIG. 5 shows a timing chart for explaining the operation of a third example of the hydraulic oil heating process performed before the continuous operation in the injection molding system according to the first embodiment. In the first example of FIG. 3, the hydraulic oil heating operation and the dry operation are exclusively controlled, but in the third example of FIG. 5, the heating operation of the hydraulic oil in the oil storage tank 20 is continued even during the dry operation. That is, in the third example, the control device 22 performs the heating operation using the hydraulic oil heating mechanism in parallel with the dry operation during at least a part of the period during which the dry operation is performed. By performing such a heating operation, in the third example, it is possible to complete the hydraulic oil heating process before the continuous operation in a shorter time than in the first example. As an example of the hydraulic oil heating mechanism when performing the heating operation in parallel, a heater that heats the hydraulic oil provided in the above-mentioned oil storage tank or hydraulic oil path may be used. Furthermore, while performing the dry operation using a pump that sends hydraulic oil to an oil distribution flow path using a plurality of pumps, the heating operation may be performed using a hydraulic oil heating mechanism by another pump.

[0049] From the above description, in the injection molding system 1 according to the first embodiment, the heating target temperature Tt, which is a temperature control parameter of the hydraulic oil in the hydraulic oil heating process before continuous operation, is defined as a parameter that can be set to any value within a temperature range equal to or higher than the operation start temperature Top. As a result, in the injection molding system 1 according to the first embodiment, it is possible to achieve high efficiency in the hydraulic oil heating process before continuous operation, such as shortening the time of the hydraulic oil heating process before continuous operation or reducing the energy consumed in the hydraulic oil heating process before continuous operation.

[0050] In addition, in the injection molding system 1 according to the first embodiment, the heating target temperature Tt is defined as a parameter that can be set to any value within a temperature range equal to or higher than the operation start temperature Top, thereby increasing the degree of freedom in the time to start the hydraulic oil heating process before continuous operation. For example, since the temperature in the factory in which the injection molding machine 10 is installed varies depending on the season, the temperature of the hydraulic oil in the oil storage tank 20 at the time of starting the hydraulic oil heating process before continuous operation varies greatly. However, in the injection molding system 1 according to the first embodiment, the heating target temperature Tt is adjusted according to the temperature of the day, so that the injection molding machine 10 can start continuous operation at the same time regardless of the temperature of the day.

[0051] Embodiment 2 In the second embodiment, another embodiment of the method for increasing the temperature of hydraulic oil implemented by the control device 22 will be described. In the description of the second embodiment, the same components as those described in the first embodiment will be denoted by the same reference numerals as in the first embodiment, and the description thereof will be omitted. In the second embodiment, two examples will be described.

[0052] Fig. 6 shows a flow chart for explaining a first example of the flow of the hydraulic oil heating process performed before continuous operation in the injection molding system according to the second embodiment. As shown in Fig. 6, in the first example of the second embodiment, when the control device 22 starts the hydraulic oil heating process before continuous operation, it first reads the heating target temperature Tt, the final heating judgment temperature Te, and the operation start temperature Top (step S11). Here, the final heating judgment temperature Te is the temperature of the hydraulic oil in the oil storage tank 20 at which it is assumed that there is no problem in skipping the dry operation after the heating operation.

[0053] In the second example of the second embodiment, before starting a temperature increase operation (step S13) similar to the temperature increase operation (steps S2 and S3) of the first embodiment, it is determined whether or not the hydraulic oil temperature To in the oil storage tank 20 is lower than the final temperature increase judgment temperature Te (step S12). If it is determined in this determination in step S12 that the hydraulic oil temperature To is lower than the final temperature increase judgment temperature Te, a temperature increase operation to re-temperature increase loop instruction process (steps S13 to S16) corresponding to the process from the temperature increase operation to the re-temperature increase loop instruction process (steps S2 to S5) of the first embodiment is performed. On the other hand, if it is determined in the determination in step S12 that the hydraulic oil temperature To is equal to or higher than the final temperature increase judgment temperature Te, the control device 22 at least performs a temperature increase operation (steps S17 and S18) for increasing the temperature of the hydraulic oil in the oil storage tank 20 to the heating target temperature Tt. Then, in the first example of the second embodiment, after the temperature increase operation (steps S17, S18) is completed, the control device 22 measures the temperature To of the hydraulic oil in the oil storage tank 20, and if the temperature To has not reached the preset operation start temperature Top, the control device 22 makes the judgment of step S12 again (step S16).

[0054] Next, the operation of the injection molding system based on the first example of the second embodiment will be described using a timing chart. FIG. 7 shows a timing chart for explaining the operation of the first example of the hydraulic oil temperature increase process performed before the continuous operation in the injection molding system according to the second embodiment. As shown in FIG. 7, in the first example of the second embodiment, the temperature increase operation is performed until timing T11 after the start of the hydraulic oil temperature increase process before the continuous operation, and the temperature of the hydraulic oil is below the final temperature increase judgment temperature Te when the dry operation is completed thereafter. Therefore, one cycle of the temperature increase operation and the dry operation is performed again (period from timing T12 to T14). Then, at timing T14, the temperature of the hydraulic oil is equal to or higher than the final temperature increase judgment temperature Te. Therefore, the control device 22 ends the hydraulic oil temperature increase process before the continuous operation without performing the dry operation after the temperature increase operation is performed at timings T14 to T15. That is, when the temperature of the hydraulic oil in the oil storage tank 20 after the dry operation is lower than the preset operation start temperature Top, a re-heating loop instruction process is performed to instruct the hydraulic oil temperature raising mechanism 21 and the drive mechanism to perform at least the temperature raising operation out of the temperature raising operation and the dry operation. In this first example, the temperature of the hydraulic oil drops during the continuous operation performed after timing T15, but the amount of decrease in the temperature of the hydraulic oil at this time is small and the temperature is sufficiently maintained at or above the operation start temperature Top.

[0055] In the first example of the second embodiment, the dry operation can be reduced by one time compared to the first embodiment, so that the time and energy required for one dry operation can be reduced.

[0056] Next, the operation of the second example of the second embodiment will be described. FIG. 8 shows a flowchart for explaining the flow of a second example of the hydraulic oil heating process performed before continuous operation in the injection molding system according to the second embodiment. As shown in FIG. 8, in the second example according to the second embodiment, the control device 22 autonomously changes the value of the heating target temperature Tt during the hydraulic oil heating process before continuous operation in response to the fact that the difference between the temperature of the hydraulic oil in the oil storage tank 20 and the operation start temperature Top becomes small. More specifically, in the second example of the second embodiment, the heating target update temperature Tch is used. Specifically, in the second example of the second embodiment, the heating target update temperature Tch is set, and at the point in time when the difference between the temperature of the hydraulic oil in the oil storage tank 20 after dry operation and the operation start temperature Top becomes smaller than the difference between the operation start temperature Top and the heating target update temperature Tch, the temperature set as the heating target temperature Tt is updated from the initial first heating target temperature Ta to a second heating target temperature Tb set to a temperature lower than the first heating target temperature Ta.

[0057] As shown in FIG. 8, in the second example of the second embodiment, when the control device 22 starts the hydraulic oil temperature increasing process before the continuous operation, first, the control device 22 reads the heating target temperature Tt, the heating target update temperature Tch, and the operation start temperature Top (step S21). The heating target temperature Tt read in step S21 is the first heating target temperature Ta. Then, in the second example of the second embodiment, the control device 22 performs a process from the temperature increasing operation to the dry operation (steps S22 to S24) corresponding to the process from the temperature increasing operation to the dry operation (steps S2 to S4) in the first embodiment. Then, after the dry operation (step S24) is completed, the control device 22 judges whether the hydraulic oil temperature To in the oil storage tank 20 is equal to or higher than the heating target update temperature Tch (step S25). Then, in the judgment of step S25, if it is judged that the hydraulic oil temperature To in the oil storage tank 20 is lower than the heating target update temperature Tch, the control device 22 performs the process from the temperature increasing operation to the dry operation (steps S22 to S24) again. On the other hand, if it is determined in step S25 that the hydraulic oil temperature To in the oil storage tank 20 is equal to or higher than the heating target update temperature Tch, the control device 22 determines whether or not the hydraulic oil temperature To in the oil storage tank 20 is equal to or higher than the operation start temperature Top (step S26). If it is determined in step S26 that the hydraulic oil temperature To in the oil storage tank 20 is lower than the operation start temperature Top, the control device 22 updates the value to be applied as the heating target temperature Tt to the second heating target temperature Tb (step S27) and performs the processes from the temperature increase operation to the dry operation (steps S22 to S24) again. On the other hand, if it is determined in step S26 that the hydraulic oil temperature To in the oil storage tank 20 is equal to or higher than the operation start temperature Top, the control device 22 ends the hydraulic oil temperature increase process before continuous operation. In addition, in the hydraulic oil heating process before continuous operation, the control shown in Figure 6 in which only the heating operation is performed one last time and dry operation is omitted, and the control shown in Figure 8 in which the heating target temperature Tt during the final heating operation is set to a temperature Tb lower than the temperature Ta may be executed in combination.

[0058] Next, the operation of the injection molding system based on the second example of the second embodiment will be described using a timing chart. FIG. 9 shows a timing chart for explaining the operation of the second example of the hydraulic oil heating process performed before the continuous operation in the injection molding system according to the second embodiment. As shown in FIG. 9, in the second example of the second embodiment, since the temperature of the hydraulic oil after the start of the hydraulic oil heating process before the continuous operation is lower than the heating target update temperature Tch, the heating operation of the first cycle is performed with the first heating target temperature Ta as the heating target temperature Tt. Then, since the temperature of the hydraulic oil at the time when the dry operation of the first cycle is completed (timing T22) is lower than the heating target update temperature Tch, the heating operation is also performed with the first heating target temperature Ta as the heating target temperature Tt until the timing T23 of the second cycle. After that, at the time when the dry operation of the second cycle is completed (timing T24), the temperature of the hydraulic oil becomes higher than the heating target update temperature Tch. Therefore, the heating operation performed until the timing T25 of the third cycle is performed with the second heating target temperature Tb as the heating target temperature Tt. Thereafter, when the temperature of the hydraulic oil at the end of the third cycle dry operation (timing T26) becomes equal to or higher than the operation start temperature Top, the hydraulic oil warming step before continuous operation is ended, and continuous operation is started.

[0059] In a second example of the second embodiment, when the hydraulic oil temperature To approaches the operation start temperature Top, the heating target temperature Tt to be applied to the subsequent heating operation is updated to a second heating target temperature Tb, which is an arbitrary temperature value lower than the initially applied first heating target temperature Ta. As a result, in the second example of the second embodiment, it is possible to reduce the energy required for the heating operation and shorten the time required for the hydraulic oil heating process before continuous operation, compared to the first embodiment.

[0060] Third embodiment In the third embodiment, a method for determining parameters used in the hydraulic oil heating process before continuous operation, including at least the start time of the temperature increase instruction process (for example, the start time of the hydraulic oil heating process before continuous operation) and the heating target temperature Tt and the operation start temperature Top, will be described. In the description of the third embodiment, the same components as those described in the first embodiment will be assigned the same reference numerals as those in the first embodiment, and the description thereof will be omitted.

[0061] In the third embodiment, the control device 22 determines a temperature rise start condition that defines at least one of the start time of the temperature rise instruction process and the heating target temperature based on temperature fluctuation factor information obtained during the period from after the previous continuous operation was stopped to the current preparation period (for example, the start time of the hydraulic oil temperature rise process before the continuous operation). In the third embodiment, three examples of the method for determining the temperature rise start condition will be described.

[0062] Here, the temperature fluctuation factor information includes at least one of the temperature in the area where the oil distribution line and the oil storage tank 20 are installed, the temperature inside the factory building in which the oil distribution line and the oil storage tank are installed, the temperature of the hydraulic oil in the oil distribution line, the temperature of the hydraulic oil in the oil storage tank, the length of time the hydraulic cylinder is idle, and the ratio between the volume of the hydraulic oil in the oil storage tank 20 and the volume of the hydraulic oil in the oil distribution line.

[0063] First, Fig. 10 shows a flow chart for explaining a first example of the flow of the temperature rise start condition determination process in the injection molding system according to the third embodiment. In the first example shown in Fig. 10, before the control device 22 starts the hydraulic oil temperature rise process before continuous operation, it acquires temperature fluctuation factor information (step S31). Next, the control device 22 refers to table information prepared in advance using the temperature fluctuation factor information acquired in step S31 as a key (step S32). Then, the control device 22 applies the temperature rise start condition corresponding to the key derived from the table information as a parameter of the hydraulic oil temperature rise process before continuous operation (step S33).

[0064] Here, the table information includes, for example, a plurality of table information prepared for each combination of the temperature in the area where the oil distribution line and the oil storage tank 20 are installed and the temperature in the factory building in which the oil distribution line and the oil storage tank are installed, and each of the plurality of table information may define the start time of the temperature increase instruction process and the heating target temperature Tt for each relationship between the temperature of the hydraulic oil in the oil distribution line and the length of the rest time of the hydraulic cylinder.

[0065] Next, Fig. 11 shows a flow chart for explaining the flow of a second example of the temperature rise start condition determination process in the injection molding system according to the third embodiment. In the second example shown in Fig. 11, before the control device 22 starts the hydraulic oil temperature rise process before continuous operation, it acquires temperature fluctuation factor information (step S41). Next, the control device 22 applies the temperature fluctuation factor information acquired in step S41 to a temperature rise start condition generation formula using the temperature fluctuation factor information as a variable to calculate an arbitrary value that defines the temperature rise start condition (step S42). Then, the control device 22 applies the temperature rise start condition calculated in step S42 to the hydraulic oil temperature rise process before continuous operation (step S43).

[0066] Here, the temperature rise start condition generating formula is at least one formula including at least one of the values ​​included in the temperature fluctuation factor information. Also, it is preferable that one temperature rise start condition generating formula is defined for each value included in the temperature rise start condition.

[0067] Next, FIG. 12 shows a flowchart for explaining the flow of a third example of the temperature rise start condition determination process in the injection molding system according to the third embodiment. As shown in FIG. 12, in the third example, the control device 22 includes a machine learning unit including a trained model. In the third example shown in FIG. 12, the control device 22 acquires temperature fluctuation factor information before starting the hydraulic oil temperature rise process before continuous operation (step S51). Next, the control device 22 provides the temperature fluctuation factor information acquired in step S51 as an input to the machine learning unit including the trained model to obtain the temperature rise start condition as an output (step S52). Then, the control device 22 applies the temperature rise start condition output from the machine learning unit in step S52 to the hydraulic oil temperature rise process before continuous operation (step S53).

[0068] Here, the machine learning unit of the control device 22 incorporates a trained model that has been trained to receive temperature fluctuation factor information as input and output a temperature rise start condition corresponding to a priority item including at least one of the time required for temperature rise and energy efficiency, and the priority item is defined as a value that can be specified by the user. The machine learning unit may also have a function of retraining the trained model using operation data that indicates the relationship between the temperature fluctuation factor information and the actual measured value of the time required for the hydraulic oil to reach the operation start temperature.

[0069] As described above, by determining the temperature rise start condition based on temperature fluctuation factor information, it is possible to maintain the start time of the hydraulic oil heating process before continuous operation constant regardless of the environment of the location where the injection molding system 1 is installed.

[0070] Furthermore, by using machine learning to generate a trained model from actual operation data, it is possible to generate a temperature rise start condition that takes into account the amount of heat absorbed by the clamping cylinder 19 and piping provided in the injection molding machine 10, whose accurate values ​​are difficult to calculate from the design information of the injection molding machine 10. By using the temperature rise start condition generated in this way, it is possible to further improve the prediction accuracy of the time required for the hydraulic oil temperature rise process before continuous operation and further reduce energy consumption.

[0071] As an example of the trained model of these machine learning methods, a neural network that performs deep learning is used. The neural network may be a convolutional neural network. It is also preferable that the agent retrains the learning model using operation data indicating the relationship between the temperature fluctuation factor information, the actual measured value of the time required for the hydraulic oil to reach the operation start temperature, data such as the amount of electric power, and the set conditions of the hydraulic oil temperature increase process as label data. In this case, backpropagation (backpropagation method) may be used to adjust the weight of the activation function of the neural network using the label data as a teacher, and reinforcement learning may be performed to give a reward to the neural network depending on the results of the label data (results of time reduction and energy saving).

[0072] Fourth embodiment In the embodiment 4, a method of using the temperature rise start condition described in the embodiment 3 will be described. In the description of the embodiment 4, the same components as those described in the embodiments 1 to 3 will be denoted by the same reference numerals as those in the embodiments 1 to 3, and the description thereof will be omitted.

[0073] Fig. 13 shows a flowchart for explaining the flow of the hydraulic oil temperature increasing process performed before continuous operation in the injection molding system according to the fourth embodiment. As shown in Fig. 13, in the hydraulic oil temperature increasing process performed before continuous operation in the injection molding system according to the fourth embodiment, the processes of steps S61 to S63 are added to the previous stage of the flowchart explained in Fig. 2.

[0074] As shown in Fig. 13, in the fourth embodiment, the control device 22 first measures the temperature of the hydraulic oil in the oil storage tank 20 (step S61). Next, the control device 22 sets the start time of the temperature increase instruction process derived using the temperature fluctuation factor information including the temperature of the hydraulic oil in the oil storage tank 20 measured in step S61 as the start time of the hydraulic oil temperature increase process (step S62). Then, when the current time reaches the start time set in step S62, the parameter reading process of step S1 is performed. Here, the heating target temperature Tt read in step S1 in the fourth embodiment is a value included in the temperature increase start condition described in the third embodiment.

[0075] As an example of setting the time to start the hydraulic oil temperature raising process (step S2) according to the situation, there is a case where the hydraulic oil is heated to the operation start temperature Top at a preset continuous operation start time. The preset continuous operation start time may have a predetermined range. This predetermined range is, for example, a range of several minutes.

[0076] In order to continuously operate the injection molding machine 10, not only the hydraulic oil but also a number of parts such as the mold and injection nozzle must be heated. Therefore, by matching the time when the temperature rise of the hydraulic oil is completed and the time when the heating of the parts that require heating is completed with the time when the continuous operation starts, it is possible to use the injection molding machine 10 more efficiently.

[0077] Here, the temperature rise time of each part when the parts necessary for continuously operating the injection molding system 1 are adjusted to the continuous operation start time will be described. FIG. 14 shows a timing chart for explaining the temperature rise schedule in the injection molding system according to the fourth embodiment. In the graph shown in FIG. 14, the horizontal axis is time and the vertical axis is temperature. FIG. 14 shows the temperature rise schedule of the heating cylinder, injection nozzle, mold temperature adjustment mechanism, and mold hot runner as parts that require heating. FIG. 14 also shows the temperature rise schedule of the hydraulic oil. Note that FIG. 14 shows that the temperature rise rate of the hydraulic oil in the oil storage tank is at a constant rate, but in reality, the temperature rises and falls as shown in FIG. 3 and the like.

[0078] As shown in FIG. 14, the temperature rise rate (temperature rise gradient) with respect to time for the parts requiring heating differs for each part. In the fourth embodiment, the temperature rise of each part is started with reference to this temperature rise gradient and the continuous operation start time. In the example shown in FIG. 14, the start time of the hydraulic oil temperature rise is also determined by taking into consideration the temperature rise gradient and the continuous operation start time, and the start timing of the hydraulic oil temperature rise process before continuous operation is determined. Note that the technical concept of the present invention also includes cases where the time to complete the temperature rise to a temperature suitable for continuous molding of the parts requiring heating in the actual temperature rise does not completely match.

[0079] By setting the heating target temperature Tt to an arbitrary value in this way, the predictability of the time to end the hydraulic oil heating process before continuous operation is improved, and the temperature of the hydraulic oil can be raised in accordance with the heating end time of other parts. By matching the heating completion time of the parts necessary for the operation of the injection molding machine 10 to the continuous operation start time, it is possible to reduce unnecessary heat retention time and improve energy efficiency. In addition, by matching the heating completion time of the parts necessary for the operation of the injection molding machine 10 to the continuous operation start time, it is possible to improve the manageability of the operation time of the injection molding machine 10. And by using the above-mentioned machine learning trained model, it is expected to improve the accuracy of matching the parts necessary for continuous operation of the injection molding system 1 to the continuous operation start time.

[0080] The present invention may also be combined with a hydraulic oil temperature drop suppression means that covers the oil storage tank 20 and the piping of the hydraulic oil flow path with a heat insulating material to prevent a sudden drop in the temperature of the hydraulic oil when the injection molding machine 10 is stopped. Alternatively, the present invention may be combined with a hydraulic oil temperature drop suppression means that uses exhaust heat from a heating cylinder, a temperature control device, etc. after the injection molding machine 10 is stopped to prevent a sudden drop in the temperature of the hydraulic oil. Furthermore, the present invention may be combined with a hydraulic oil temperature maintaining means provided in the oil storage tank 20 with a heater to maintain the temperature of the hydraulic oil at a constant temperature or to maintain the temperature so as not to drop suddenly.

[0081] In the case where the oil storage tank 20 or the like is provided with a hydraulic oil temperature drop suppression means or a hydraulic oil temperature maintenance means, the hydraulic oil temperature in the oil storage tank 20 at the start of the hydraulic oil heating process is kept at a relatively high temperature, and the temperature difference with the heating target temperature Tt is small. Therefore, there is an advantage that the amount of energy required to raise the hydraulic oil temperature to the heating target temperature Tt for the first time is small. However, even in the above case, the temperature of the hydraulic oil in the hydraulic cylinders such as the mold clamping cylinder 19 has dropped at the start of the hydraulic oil heating process, as in the above embodiment. Therefore, even when the injection molding machine 10 is provided with a hydraulic oil temperature drop suppression means or a hydraulic oil temperature maintenance means, it is necessary to perform dry operation as in the embodiment. In addition, the second and subsequent hydraulic oil heating and dry operation are also performed in the same manner as in the above embodiment.

[0082] The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0083] 1. Injection Molding System 10 injection molding machine 11 Fixed plate 12 Movable plate 13 Tie bar 14 Mold 15 Mold 16 Injection nozzle 17 Movable platen movement mechanism 18 Half nut lock mechanism 19 Clamping cylinder 20 Oil Storage Tank 21 Hydraulic oil temperature rise mechanism 22 Control device 23 Oil temperature sensor 31 Pump 32 Directional control valve 33 Relief valve 34 Check valve 35 Pressure Control Valve 36 Directional Control Valve

Claims

1. An oil distribution flow path including a hydraulic cylinder and a hydraulic oil path between the hydraulic cylinder and an oil storage tank; an oil storage tank for storing hydraulic oil used in the hydraulic cylinder; a hydraulic oil heating mechanism for heating the temperature of the hydraulic oil in the oil storage tank; A control device that controls each of the drive mechanism that drives the hydraulic cylinder and the hydraulic oil temperature raising mechanism, The control device has a heating target temperature defined as a parameter that can be set to any value within a temperature range equal to or higher than an operation start temperature, During a preparation period before the hydraulic cylinder is continuously operated, a temperature increase instruction process for instructing the hydraulic oil temperature increase mechanism to perform a temperature increase operation for increasing the temperature of the hydraulic oil stored in the oil storage tank to the heating target temperature; a dry operation instruction process for instructing the drive mechanism to perform a dry operation in which the hydraulic oil held in the oil distribution flow path and the hydraulic oil in the oil storage tank are mixed; and a re-heating loop instruction process that instructs the hydraulic oil heating mechanism and the drive mechanism to perform at least the heating operation of the heating operation and the dry operation when the temperature of the hydraulic oil in the oil storage tank after the dry operation is lower than a preset operation start temperature.

2. The injection molding system according to claim 1 , wherein the control device performs the temperature increasing operation in parallel with the dry operation during at least a portion of a period during which the dry operation is being performed.

3. The injection molding system according to claim 1 , wherein the heating target temperature is set with the recommended use temperature of the hydraulic oil as an upper limit value.

4. The injection molding system according to claim 1 , wherein the heating target temperature is autonomously changed by the control device in response to a decrease in a difference between the temperature of the hydraulic oil in the oil storage tank and the operation start temperature.

5. The injection molding system according to claim 1, wherein the control device determines a temperature rise start condition that defines at least one of a start time of the temperature rise instruction process and the heating target temperature based on temperature fluctuation factor information obtained during the period from the time the previous continuous operation was stopped until the current preparation period.

6. 6. The injection molding system of claim 5, wherein the temperature fluctuation factor information includes at least one of the following: the temperature in the area where the oil distribution line and the oil storage tank are installed, the temperature inside the factory building in which the oil distribution line and the oil storage tank are installed, the temperature of the hydraulic oil in the oil distribution line, the temperature of the hydraulic oil in the oil storage tank, the length of time the hydraulic cylinder is idle, and the ratio between the volume of the hydraulic oil in the oil storage tank and the volume of the hydraulic oil in the oil distribution line.

7. The control device incorporates a trained model that is trained to input the temperature fluctuation factor information and output the heating start condition corresponding to priority items including at least one of the time required for heating and energy efficiency, and the priority items are defined as values ​​that can be specified by the user.

8. The injection molding system of claim 7, wherein the control device re-learns the learned model using operational data indicating a relationship between the temperature fluctuation factor information and an actual measured value of the time required for the hydraulic oil to reach the operation start temperature.

9. 2. The injection molding system according to claim 1, wherein the hydraulic oil heating mechanism includes at least one of a relief valve provided in a path that circulates the hydraulic oil in the oil storage tank through a flow path separate from the oil distribution flow path, and a heater that heats the hydraulic oil in the oil storage tank or the hydraulic oil path.

10. The injection molding machine of the injection molding system has a heater corresponding to related components including a mold clamped by the hydraulic cylinder, a heating cylinder for heating an injection material, and an injection nozzle for injecting the injection material into a cavity formed by the mold; The control device has the heater as at least one of the objects to be controlled, The control device includes: Calculating the time required for each of the related components to reach a specified temperature set for each of them; 2. The injection molding system according to claim 1, wherein the temperature rise start time for each part is set so that the time at which each of the related components reaches the specified temperature and the time at which the hydraulic oil reaches the operation start temperature are within a certain range of a preset production start time.

11. an oil distribution flow path including a hydraulic cylinder and a hydraulic oil path between the hydraulic cylinder and an oil storage tank; an oil storage tank for storing hydraulic oil used in the hydraulic cylinder; a hydraulic oil heating mechanism for heating the temperature of the hydraulic oil in the oil storage tank; A control device for controlling each of a drive mechanism for driving the hydraulic cylinder and the hydraulic oil heating mechanism, comprising: The oil temperature control program The heating target temperature is defined as a parameter that can be set to any value within a temperature range equal to or higher than the operation start temperature, During a preparation period before the hydraulic cylinder is continuously operated, a temperature increase instruction process for instructing the hydraulic oil temperature increase mechanism to perform a temperature increase operation for increasing the temperature of the hydraulic oil stored in the oil storage tank to the heating target temperature; a dry operation instruction process for instructing the drive mechanism to perform a dry operation in which the hydraulic oil held in the oil distribution flow path and the hydraulic oil in the oil storage tank are mixed; An oil temperature control program that performs a re-heating loop instruction process that instructs the hydraulic oil heating mechanism and the drive mechanism to perform at least the heating operation of the heating operation and the dry operation when the temperature of the hydraulic oil in the oil storage tank after the dry operation is lower than a predetermined operation start temperature.

12. An oil distribution flow path including a hydraulic cylinder and a hydraulic oil path between the hydraulic cylinder and an oil storage tank; an oil storage tank for storing hydraulic oil used in the hydraulic cylinder; a hydraulic oil heating mechanism for adjusting the temperature of the hydraulic oil in the oil storage tank; A control device that controls each of a drive mechanism that drives the hydraulic cylinder and the hydraulic oil temperature raising mechanism, the control method comprising the steps of: The heating target temperature is defined as a parameter that can be set to any value within a temperature range equal to or higher than the operation start temperature, During a preparation period before the hydraulic cylinder is operated, a temperature increase instruction process for instructing the hydraulic oil temperature increase mechanism to perform a temperature increase operation for increasing the temperature of the hydraulic oil stored in the oil storage tank to the heating target temperature; a dry operation instruction process for instructing the drive mechanism to perform a dry operation in which the hydraulic oil held in the oil distribution flow path and the hydraulic oil in the oil storage tank are mixed; a re-heating loop instruction process for instructing the hydraulic oil heating mechanism and the drive mechanism to perform at least the heating operation of the heating operation and the dry operation when the temperature of the hydraulic oil in the oil storage tank after the dry operation is lower than a preset operation start temperature; An oil temperature control method in which the above is performed by a computer.

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