Device for controlling or regulating an injection molding machine

Abstract

A technology is provided that allows the relationship between transferred heat and shear heat to be easily obtained as an indicator of molding conditions in an injection molding machine. This control device 10Control of an injection molding machine 1 comprises: an operation information acquisition unit 11 which acquires operation information related to the operation of each of heaters 24a to 24d and a screw 23; a characteristic information acquisition unit 12 which acquires characteristic information related to the characteristics of the injection molding machine 1; a heater heat generation amount calculation unit 13 which calculates the amount of heat generated by the heaters 24a to 24d based on the acquired operation information and characteristic information; a heater heat transfer amount calculation unit 14 which calculates the amount of heat transferred from the heaters 24a to 24d to a resin based on the amount of heat generated by the heaters 24a to 24d during molding in a state where a cylinder 22 is heated to a prescribed target temperature orset temperature, and the amount of heat generated by the heaters 24a to 24d when molding is stopped in a state where the cylinder 22 is maintained at the prescribed set temperature; a shear heat amount calculation unit 15 that calculates the amount of shear heat due to rotation of the screw 23; a plasticization index calculation unit 16 that calculates a plasticization-related index based on the amount of heat transferred from the heaters as calculated by the heater heat amount calculation unit 14 and the amount of shear heat as calculated by the shear heat amount calculation unit 15; and an output unit 20 that outputs the result of the calculation performed by the plasticization index calculation unit 16.

Description

TECHNICAL FIELDThe present disclosure relates to a control device for an injection molding machine.BACKGROUND ARTIn the related art, an injection molding machine is known in which pellets placed in a hopper are melted in a cylinder and injected into a mold. A heater is disposed on an outer periphery of the cylinder of the injection molding machine. The heater heats the cylinder to melt the pellets (molding material). Further, by rotating the screw disposed in the cylinder, the molding material is kneaded and plasticized. In this manner, the molding material is plasticized by transferred heat from the heater and shear heat generated by the shearing action during screw rotation.As a control method of such an injection molding machine, a method of detecting a temperature difference between a heating cylinder temperature at a certain amount of heat generated by the heater and a cylinder temperature measured in advance as temperature information due to shear heat has been proposed (see, for example, Patent Document 1).List of InstructionsPatent DocumentPatent Document 1: Japanese Unexamined Patent Application, Publication No. 2001-225372DISCLOSURE OF THE INVENTIONProblems to be Solved by the InventionIncidentally, the relationship between the transferred heat and the shear heat applied to the molding material is closely related to the melt state (quality) of the plasticized molding material. In general, it is said that molded material of good quality can be obtained when plasticizing is performed mainly by transferred heat. On the other hand, when plasticizing is performed mainly by shear heat, plasticizing can be performed efficiently.In Patent Document 1, the energy amounts of transferred heat and shear heat are not specifically calculated. Therefore, it is difficult to use transferred heat and shear heat as aids in determination of molding conditions. Since the relationship between transferred heat and shear heat is a trade-off relationship between quality and efficiency, it is preferable that the relationship between transferred heat and shear heat can be easily obtained as an index of molding conditions.The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide a technique capable of easily obtaining a relationship between transferred heat and shear heat as an index of molding conditions in an injection molding machine.Means for Solving the ProblemsThe present disclosure is directed to a control device for an injection molding machine, including: a cylinder; at least one heater provided around the cylinder; and a screw provided inside the cylinder. The control device includes: an operation information acquisition unit that acquires operation information related to an operation of the heater and the screw; a characteristic information acquisition unit that acquires characteristic information related to characteristics of the injection molding machine; a heater generation heat amount calculation unit that calculates a heater generation heat amount based on acquired operation information and acquired characteristic information; a heater transferred heat amount calculation unit that calculates a heat amount transferred from the heater to a resin based on a heat amount generated by the heater at a time of performing molding in a state where the cylinder is maintained at a predetermined set temperature and a heat amount generated by the heater at a time of stopping molding in a state where the cylinder is maintained at a predetermined set temperature; a shear heat amount calculation unit that calculates a shear heat amount due to rotation of the screw; a plasticizing index calculation unit that calculates a plasticizing index based on an amount of transmitted heat calculated by the heat amount calculation unit from the heater and an amount of shear heat calculated by the shear heat amount calculation unit; and an output unit that outputs a calculation result of the plasticizing index calculation unit.Effects of the InventionAccording to the present disclosure, it is possible to provide a technique capable of easily obtaining a relationship between transferred heat and shear heat as an index of molding conditions in an injection molding machine.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a schematic view illustrating a configuration of an injection molding machine according to a first embodiment; FIG. 2 is a perspective view illustrating a heating device disposed in a cylinder according to the first embodiment; FIG. 3 is a functional block diagram of a control device of the injection molding machine according to the first embodiment; FIG. 4 is a schematic diagram for illustrating a heat balance at the time of performing shaping according to the first embodiment; FIG. 5 is a schematic diagram for illustrating a heat balance at the time of stopping forming according to the first embodiment; FIG. 6 is a schematic diagram illustrating the energy balance around a cylinder; FIG. 7 is a flowchart illustrating an example of the flow of processing by the control device of the injection molding machine according to the first embodiment; FIG. 8 is a schematic diagram for illustrating a heat balance at the time of performing shaping according to a second embodiment; FIG. 9 is a schematic diagram for illustrating a heat balance at the time of stopping shaping according to the second embodiment; FIG. 10 is a functional block diagram of a control device of an injection molding machine according to the second embodiment; FIG. 11 is a flowchart illustrating an example of the flow of processing by the control device of the injection molding machine according to the second embodiment; and FIG. 12 is a functional block diagram of a control device of an injection molding machine according to a third embodiment.PREFERRED MODE FOR IMPLEMENTING THE INVENTIONHereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the description of the second and subsequent embodiments, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate.[First Embodiment]FIG. 1 is a schematic view illustrating a configuration of an injection molding machine 1 according to a first embodiment. FIG. 2 is a perspective view illustrating heaters 24 ato 24 ddisposed in a cylinder 22 of the injection molding machine 1 according to the first embodiment. The injection molding machine 1 of the first embodiment includes an injection unit 2, a mold clamping unit 3, a control device 10, and a display device 6.The injection unit 2 is an injection device including a hopper 21, a cylinder 22, a scroll 23, and a cooling jacket 26. The cylinder 22 is, for example, a cylindrical body. The resin stored in the hopper 21 is supplied to the cylinder 22. The screw 23 is disposed inside the cylinder 22, and conveys the resin to the distal end of the cylinder 22 by rotation. the cooling jacket 26 is a device that cools the inside of the cylinder 22 (for example, a portion adjacent to the root inside the cylinder 22) and in which the cooling water circulates.For example, as illustrated in FIG. 2, a plurality of heaters 24 ato 24 dare arranged along the axial direction of the cylinder 22. Specifically, a plurality of heaters 24 ato 24 dare arranged from a nozzle portion 25 located at the distal end of the cylinder 22 in the axial direction to the proximal end. The number of the heaters 24 ato 24 dis not particularly limited.In the present embodiment, four heaters 24 ato 24 dare arranged along the axial direction so as to cover the outer periphery of the cylinder 22. The heater 24 ais one of the distal end side heaters disposed on the nozzle portion 25. The heaters 24 bto 24 dare located on the upstream side of the nozzle portion 25 in the conveyance direction of the pellets. Among these heaters, the heater 24 bis one of the distal-end side heaters that is closest to the nozzle portion 25. The heater 24d is located farthest from the nozzle portion 25, and the heater 24c is located between the heater 24b and the heater 24d.When the cylinder 22 is heated by the heaters 24a to 24d, the pellets are melted. The molten pellets are conveyed to the nozzle portion 25 by the screw 23 and injected into the mold 5.The mold clamping unit 3 is a device that clamps the mold 5. The mold clamping unit 3 molds the mold 5 by clamping to produce the molded product.Next, the control device 10 will be described. FIG. 3 is a functional block diagram of the control device 10 of the injection molding machine 1 according to the first embodiment. The control device 10 of the injection molding machine 1 according to the first embodiment is configured using, for example, a computer including a memory such as ROM (Read Only Memory) or RAM (Random Access Memory), a CPU (Control Processing Unit), and a communication control unit connected to each other via a bus. The functions and operations of the functional units of the control device 10 described below are realized by cooperation of a CPU, a memory, and a control program stored in the memory, which are mounted on the computer.The control device 10 includes, as functional units, an operation information acquisition unit 11, a characteristic information acquisition unit 12, a heater generated heat amount calculation unit 13, a heater transmitted heat amount calculation unit 14, a shear heat amount calculation unit 15, a plasticizing index calculation unit 16, and an output unit 20.The operation information acquisition unit 11 acquires operation information related to the operation of each of the heaters 24 ato 24 d. The operation information regarding each of the heaters 24 ato 24 drefers to an operation ratio of each of the heaters 24 ato 24 din the present embodiment. The duty ratio is, for example, an index of an operation state indicated as 0 to 100%. The duty ratio is determined based on, for example, an output such as a voltage of each of the heaters 24 ato 24 d.Further, the operation information acquisition unit 11 also acquires information related to the operation of the scroll 23 as operation information. The information related to the operation of the worm 23 is, for example, a motor electric current at the time of metering, a rotational angular speed of the worm 23, or the like.The characteristic information acquisition unit 12 acquires characteristic information indicating characteristics of the injection molding machine 1. The characteristic information is, for example, the capacity of each of the heaters 24 ato 24 d. The capacity of each of the heaters 24 ato 24 dis a rated capacity that is 1500 W at 200 V.Further, the characteristic information acquisition unit 12 also acquires information related to the characteristics of the scroll 23 as characteristic information. The information related to the characteristics of the worm 23 is, for example, a reduction ratio or a mechanical efficiency between the worm 23 and a motor that rotates the worm 23, a torque constant of the rotation motor that rotates the worm 23, or the like.The heater generation amount calculation unit 13 calculates the amount of heat generation by each of the heaters 24 ato 24 dbased on the acquired operation information and characteristic information. The heater generation amount calculation unit 13 calculates, for example, the amount of heat generated by each of the heaters 24 ato 24 din a state where the cylinder 22 is maintained at a preset temperature in a predetermined period of time. The heater generated heat amount calculation unit 13 may calculate the generated heat amount by performing compensation based on the difference between the rated voltages of the heaters 24 ato 24 dand the actual power supply voltage of the injection molding machine 1.An example of a method of calculating the amount of heat generated by the heater generation amount calculation unit 13 will be described. The amount of heat generated can be calculated by, for example, the following expression (1). In the expression (1), E Hi represents a generated heat amount, t 1 represents a calculation start time, t 2 represents a calculation end time, W i represents a heater capacity, and r i represents a heater duty ratio. [Expression 1]The heater-transmitted heat amount calculation unit 14 calculates the heat amount transmitted from each of the heaters 24 ato 24 dto the resin based on the calculation result of the heater-generated heat amount calculation unit 13. An example of a method of calculating the amount of transferred heat by the heater-transferred heat amount calculation unit 14 will be described. The amount of heat transferred from the heaters 24a to 24d to the resin is denoted by E Ti. When the generated heat quantity at the time of performing forming is defined as E Hi and the generated heat quantity at the time of stopping forming is defined as E' Hi in a state where the cylinder 22 is maintained at a predetermined target temperature, the amount of transferred heat is expressed by the following expression (2). As represented in the following expression (2), it is possible to calculate the amount of transferred heat E Ti based on the difference between the generated heat amount E Hi at the time of performing shaping and the generated heat amount E' Hi at the time of stopping shaping. [Expression 2]Expression (2) will be described with reference to FIGS. 4 and 5. FIG. 4 is a schematic diagram for illustrating a heat balance at the time of performing shaping. FIG. 5 is a schematic diagram for illustrating a heat balance at the time of stopping forming. As illustrated in FIG. 4, in consideration of the heat balance at the time of performing shaping, the amount of heat E Hi, generated at the time of performing shaping, at which the cylinder 22 is maintained at the target temperature, may be regarded as the sum of the amount of transferred heat E Ti and various types of heat dissipation. Here, the various kinds of heat dissipation are the sum of the amount of heat transferred toward the front side (adjacent to the nozzle portion 25), the amount of heat transferred toward the rear side (opposite side of the nozzle portion 25), and the amount of heat dissipated from the surface of the heater 24 b, among the amounts of heat applied to the heater 24 b.On the other hand, considering the heat balance at the time of stopping molding, unlike at the time of performing molding, the screw 23 inside the cylinder 22 is stopped to be in a lead state in which the resin does not flow. In this state, since it can be assumed that the resin temperature is equal to the temperature of the cylinder 22, the amount of heat generated by the heater 24 bis not transmitted to the resin. Therefore, as illustrated in FIG. 5, it can be assumed that the generated heat quantity E' Hi at the time of stopping forming in which the cylinder 22 is maintained at the target temperature is equal to various kinds of heat dissipation. Since various kinds of heat dissipation can be considered to be equal to that at the time of performing shaping, the amount of transferred heat E Ti can be obtained by subtracting the generated heat amount E' Hi from the generated heat amount E Hi to exclude the various kinds of heat dissipation.The heater-transmitted heat amount calculation unit 14 of the present embodiment calculates the total amount of transmitted heat, which is the sum of the amount of transmitted heat from the heaters 24 ato 24 d, based on the above-described concept. The sum of the amount of heat transferred from the heaters 24a to 24d to the resin is defined as the total amount of transferred heat E T. When the amount of heat generated by each of the heaters 24a to 24d at the time of performing molding is defined as E Hi and the amount of heat generated by each of the heaters 24a to 24d at the time of stopping molding is defined as E' Hi in a state where the cylinder 22 is maintained at a predetermined target temperature, the total amount of transferred heat can be expressed by the following expression (3). In Expression (3), I=0, 1, 2,..., k. [Expression 3]Next, the shear heat amount calculation unit 15 will be described. The shear heat amount calculation unit 15 calculates the shear heat amount due to the rotation of the scroll 23 based on the operation information acquired by the operation information acquisition unit 11 and the characteristic information acquired by the characteristic information acquisition unit 12. The shear heat amount refers to a shear heat amount caused by a shear action due to the rotation of the screw 23.An example of a method of calculating the shear heat amount by the shear heat amount calculation unit 15 will be described. The amount of shear heat can be calculated by, for example, the following expression (4). In Expression (4), Es represents the shear heat of the screw, K T represents the torque constant of the rotating motor that rotates the screw, r represents the motor current at the time of metering, R represents the reduction ratio between the motor and the screw, ω represents the rotational angular speed of the screw, and η represents the mechanical efficiency. [Expression 4]Next, the plasticizing index calculation unit 16 will be described. The plasticizing index calculation unit 16 calculates a total amount of transferred heat from the entire cylinder 22, and calculates a plasticizing related index such as a total plasticizing state (quality) and an energy efficiency inside the cylinder 22 using the total amount of transferred heat.FIG. 6 is a schematic diagram illustrating the energy balance around the cylinder 22. As illustrated in FIG. 6, when the total amount of heat absorbed by the resin material is defined as E M the total amount of heat E M can be expressed by the following expression (5) based on the total amount of transferred heat E T and the shear heat amount Es. [Expression 5]As the amount of heat dissipated to the atmosphere, the amount of heat dissipated to the air E Ri, the amount of heat dissipated by the cooling water flowing through the cooling jacket 26, and the amount of heat dissipated to the engine main body E 0 may be considered. As described above, when the amount of heat E generated by each of the heaters 24 ato 24 dis assumed to be Hi the total amount of transferred heat E T of all the heaters 24 ato 24 dmay be expressed by the following expression (6). [Expression 6]Here, an index representing the plasticized state will be described. E T: E S is the ratio between the amount of shear heat and the amount of transferred heat, i.e., the division of the total amount of heat E M. absorbed by the resin material. Under the condition that there is a relationship in which the amount of transferred heat is dominant, the energy efficiency is poor, but the melt quality of the resin is good. Under the condition that there is a relationship in which the shear heat is dominant, the energy efficiency is good, but the melt quality is poor. If the total amount of heat E transferred from the heaters 24 ato 24 dto the resin T can be calculated, the ratio between the amount of transferred heat and the amount of shear heat can also be calculated. Therefore, E T: E S is an index indicating the plasticized state.The plasticizing index calculation unit 16 of the present embodiment calculates the ratio (E T: E S) of the amount of transferred heat to the amount of shear heat as a plasticizing related index based on the information of the total amount of transferred heat E T calculated by the heater-transferred heat amount calculation unit 14 and the amount of shear heat Es calculated by the shear heat amount calculation unit 15. In addition, the plasticizing index calculation unit 16 may calculate the plasticizing-related energy efficiency using the amount of heat transferred from the heater.The output unit 20 will be described. The output unit 20 outputs the plasticizing related index calculated by the plasticizing index calculation unit 16. In the present embodiment, the processing of displaying the "ratio between the amount of transferred heat and the amount of shear heat (E T: E S)" and the "energy efficiency" which are calculation results of the plasticizing index calculation unit 16 is executed on the display device 6 of the injection molding machine 1. The output unit 20 may be configured to output the determination result of the plasticizing index calculation unit 16 to an external computer that is connected to the injection molding machine 1 and is different from the display device 6 of the injection molding machine 1.The display device 6 is, for example, an output device such as a liquid crystal display or a touch panel display. In addition, the calculation result of the plasticizing index calculation unit 16 may be output by a sound generation device that outputs sound instead of the display device 6.Next, a flow of processing for calculating the amount of transferred heat E Ti will be described with reference to FIG. 7. FIG. 7 is a flowchart illustrating an example of the flow of processing by the control device 10 of the injection molding machine 1 according to the first embodiment.When the processing for calculating the amount of transferred heat E Ti is started, the characteristic information acquisition unit 12 acquires characteristic information indicating the characteristic of the injection molding machine 1 (step S 10), and the operation information acquisition unit 11 acquires the operation ratio related to the operation of the heaters 24 ato 24 das operation information (step S 11). The operation information and the characteristic information are acquired from, for example, various sensors, a storage unit (not illustrated) of the control device 10, an external computer (not illustrated), or the like.The heater generation amount calculation unit 13 calculates the heater generation amount generated by the heaters 24 ato 24 dbased on the acquired operation information and characteristic information (step S 12). The heater generation amount calculation unit 13 calculates the amount of heat generated by each of the heaters 24 ato 24 din a state where the cylinder 22 is maintained at a predetermined target temperature, for example, based on the operation ratios of the heaters 24 ato 24 dand the capacities of the heaters 24 ato 24 d.Next, the heater-transmitted heat amount calculation unit 14 calculates the heater-transmitted heat amount from the heaters 24 ato 24 dto the resin (step S 13). The heater-transmitted heat amount calculation unit 14 substitutes, for example, the heat amount E Hi generated by the heaters 24a to 24d at the time of performing molding and the heat amount E' Hi generated by the heaters 24a to 24d at the time of stopping molding into the above expression (2), and calculates the amount of heat E Ti. transmitted from the heaters 24a to 24d to the resin. Then, the heater transferred heat amount calculation unit 14 calculates the total amount of transferred heat E T from all the heaters 24 ato 24 das shown in Expression (3).Next, the shear heat amount calculation unit 15 acquires the shear heat amount based on the operation information acquired by the operation information acquisition unit 11 and the characteristic information acquired by the characteristic information acquisition unit 12 (step S 14).Next, the plasticizing index calculation unit 16 calculates an index indicating the plasticized state based on the total amount of transferred heat E T calculated by the heater-transferred heat amount calculation unit 14 and the shear heat amount Es calculated by the shear heat amount calculation unit 15 (step S 15).When the calculation result of the plasticizing index calculation unit 16 is output, the output unit 20 outputs the calculation result (step S 16). For example, the output unit 20 performs processing of displaying a numerical value, a character, a symbol, a diagram, an image, a combination thereof, or the like as the calculation result of the plasticizing index calculation unit 16 on the display device 6.After the processing by the output unit 20 in step S 15, when the forming process is continued, the control device 10 returns the processing to step S 11 and executes the processing of step S 11 and the subsequent steps again (step S 17; Yes). On the other hand, upon detecting the stop of the forming processing, the control device 10 performs processing for stopping the forming and ends the process (step S 17; No). Whether to continue or stop the forming process is determined by the control device 10 based on, for example, an operation of the user or whether the plasticized state satisfies a predetermined condition.According to the control device 10 of the injection molding machine 1 according to the above-described first embodiment, the following advantageous effects are obtained. That is, the injection molding machine 1 includes the cylinder 22, heaters 24 ato 24 ddisposed around the cylinder 22, and the screw 23 disposed inside the cylinder 22. The control device 10 of the injection molding machine 1 includes the operation information acquisition unit 11 that acquires operation information related to the operations of the heaters 24 ato 24 dand the screw 23, the characteristic information acquisition unit 12 that acquires characteristic information related to the characteristics of the injection molding machine 1, the heater generated heat amount calculation unit 13 that calculates a heat amount generated by the heaters 24 ato 24 dbased on the acquired operation information and characteristic information, the heater transmitted heat amount calculation unit 14 that calculates the heater transmitted heat amount transmitted from the heaters 24 ato 24 dto the resin based on the heat amount generated by the heaters 24 ato 24 dat the time of performing molding in a state, in which the cylinder 22 is maintained at a predetermined target temperature and a quantity of heat generated by the heaters 24 ato 24 dat the time of stopping molding in a state where the cylinder 22 is maintained at a predetermined target temperature, the shear heat amount calculation unit 15 calculating a shear heat amount due to rotation of the screw 23, the plasticizing index calculation unit 16 calculating a plasticizing index based on a quantity of transferred heat calculated by the heater transferring heat amount calculation unit 14 and a shear heat amount calculated by the shear heat amount calculation unit 15, and the output unit 20 outputting the calculation result of the plasticizing index calculation unit 16. With such a configuration, it is possible to obtain an index indicating the plasticized state of the resin in consideration of the shear heat due to the rotation of the screw 23, so that it is possible to easily obtain the relationship between the transferred heat and the shear heat as an index of the molding condition, and it is possible to set an appropriate and efficient molding condition based on the index. In addition, since the dispensing unit 20 dispenses a plasticizing index, it is possible for the user to accurately recognize the plasticized state of the resin without requiring any special sensor even during continuous molding. In addition, the information output by the output unit 20 may also be used to examine the cause of a molding error.In addition, according to the control device 10 of the injection molding machine 1 of the present embodiment, the plasticizing index calculation unit 16 calculates the ratio between the amount of heat transferred to the resin from the heaters 24 ato 24 dand the amount of shear heat as the plasticizing index. Thus, it is possible for the user to recognize the plasticizing quality of the resin based on the relationship between the amount of transferred heat and the amount of shear heat. For example, when the transferred heat is relatively high, it is seen that the energy efficiency is low, but the melt state of the resin is good. On the other hand, when the shear heat is relatively high, the energy efficiency is high, but the melt state is not good.[Second Embodiment]In the second embodiment, control is performed in consideration of the amount of heat dissipated from the heaters 24 ato 24 d. The heat balance in consideration of the dissipated heat amount of the second embodiment will be described with reference to FIGS. 8 and 9. FIG. 8 is a schematic diagram for illustrating a heat balance at the time of performing shaping according to the second embodiment, and FIG. 9 is a schematic diagram for illustrating a heat balance at the time of stopping shaping according to the second embodiment.Even in a state where the cylinder 22 is maintained at a predetermined target temperature, the operation ratios indicating the operation states of the heaters 24 ato 24 dare different between the time of performing shaping and the time of stopping shaping. When the operating ratios of the heaters 24 ato 24 dare different, the surface temperatures of the heaters 24 ato 24 dare also different, and the amount of heat dissipated from the surfaces of the heaters 24 ato 24 dis also different. For example, the dissipated heat quantity E Ri at the time of performing shaping shown in FIG. 8 is different from the dissipated heat quantity E' Ri at the time of stopping shaping (heat dissipation quantity E ri ≠ (non-symbol) heat dissipation quantity E' Ri). shown in FIG. 9. Therefore, the amount of transferred heat can be calculated more accurately by compensating the difference between the amount of heat dissipated from the heaters 24 ato 24 dat the time of performing shaping and at the time of stopping shaping.As illustrated in FIG. 8, the generated heat amount E Hi at the time of performing shaping may be regarded as a value obtained by adding the dissipated heat amount E Ri and other heat dissipation except the dissipated heat amount E Ri of various types of heat dissipation to the amount of transferred heat E Ti. Here, the other heat dissipation refers to the amount of heat transfer forward (toward the nozzle portion 25) and the amount of heat transfer rearward (toward the opposite side of the nozzle portion 25) among the amounts of heat applied to the heater 24 b.The heat dissipation from the heater surface is divided into two types, convection and radiation, and the dissipated amount of heat can be calculated from the sum of the two types of convection and radiation. In the second embodiment, the dissipated heat amount is calculated using the heater surface area, the heat transfer coefficient, the emissivity, and the Stefan-Boltzmann coefficient acquired by the characteristic information acquisition unit 12 together with the heater surface temperature and the ambient temperature acquired by the operation information acquisition unit 11. In this calculation, the calculation may be performed on the assumption that the cylinder 22 has a simple cylindrical shape. The ambient temperature and the temperature of the heater surface are obtained, for example, using a detection value of a temperature sensor (not illustrated) or by estimating by a predetermined function.An example of a method for calculating the dissipated heat amount will be described. The heater convection heat dissipation amount may be calculated using, for example, the following expression (7). Further, the heater radiation heat dissipation amount may be calculated using the following expression (8), for example. In the expression, E rci represents the heater convection heat dissipation amount, T Hi represents the heater surface temperature, T C represents the ambient temperature, A i represents the heater area, h represents the heat transfer coefficient, E Rri represents the heater radiation heat dissipation amount, ε represents the emissivity, and σ represents the Stephan-Boltzmann coefficient. [Expression 7] [Expression 8]It is assumed that the amount of heat transferred from a certain heater 24 to adjacent zones such as the front zone and the rear zone in the axial direction of the cylinder 22 hardly changes when the target temperature of the cylinder 22 is the same. In the examples of FIGS. 8 and 9, the amount of heat transferred to the heater 24 aand the heater 24 czone adjacent to the heater 24 bdoes not change. Therefore, it can be assumed that the other heat dissipation excluding E Ri among the various heat dissipations at the time of performing shaping becomes equal to the other heat dissipation excluding E' Ri among the other heat dissipations at the time of stopping shaping. In the second embodiment, the amount of transferred heat is calculated using the following expression (9). [Expression 9]The total amount of transferred heat, which is the sum of the amount of transferred heat from the heaters 24 ato 24 d, is calculated based on the above-described concept. The sum of the amount of heat transferred from the heaters 24a to 24d to the resin is defined as the total amount of transferred heat E T. In a state where the cylinder 22 is maintained at a predetermined target temperature, the amount of heat generated by each of the heaters 24 ato 24 dat the time of performing molding is defined as E Hi and the dissipated amount of heat is defined as E Ri. In addition, in a state where the cylinder 22 is maintained at a predetermined target temperature, the amount of heat generated by each of the heaters 24a to 24d at the time of stopping forming is defined as E' Hi and the dissipated amount of heat is defined as E' Ri. The total amount of transferred heat can then be expressed by the following expression (10). [Expression 10]Next, a specific example of the control device 10 aof the second embodiment will be described. FIG. 10 is a functional block diagram of the control device 10 aof the injection molding machine 1 according to the second embodiment. FIG. 11 is a flowchart illustrating an example of the flow of processing by the control device 10 aof the injection molding machine 1 according to the second embodiment.As illustrated in FIG. 10, the control device 10 aaccording to the second embodiment is different from the control device 10 of the injection molding machine 1 according to the first embodiment in that a heater dissipated heat amount calculation unit 17 is further provided, and regarding the transferred heat amount calculation processing E Ti and the other configuration is the same as that of the first embodiment.When the processing for calculating the amount of transferred heat E Ti is started, as illustrated in FIG. 11, the characteristic information acquisition unit 12 acquires the shapes of the heaters 24 ato 24 dand the constants related to heat dissipation from the heaters 24 ato 24 das the characteristic information in addition to the capacities of the heaters 24 ato 24 dand the information related to the scroll 23 (step S 20).In addition, the operation information acquisition unit 11 acquires a heater surface temperature and an ambient temperature as the operation information in addition to the operation ratios of the heaters 24 ato 24 dand the information related to the scroll 23 (step S 21). The constant related to heat dissipation is, for example, a heat transfer coefficient, an emissivity, a Stefan-Boltzmann coefficient, or the like.Similarly to the first embodiment, the heater generation amount calculation unit 13 calculates the heater generation amount by the heaters 24 ato 24 dbased on the acquired operation information and characteristic information (step S 22).The heater dispersed heat amount calculation unit 17 calculates the heater dispersed heat amount of each of the heaters 24 ato 24 dbased on the operation information acquired by the operation information acquisition unit 11 and the characteristic information acquired by the characteristic information acquisition unit 12 (step S 23). The amount of heat dissipated from each of the heaters 24 ato 24 drefers to a dissipated amount of heat in a state where the cylinder 22 is maintained at a predetermined target temperature.After the heat dissipated amount calculation processing by the heater dissipated amount calculation unit 17, the heater transferred amount calculation unit 14 calculates the heat transferred amount E from the heaters 24 ato 24 dto the resin Ti( step S 24). For example, the heater-transmitted heat amount calculation unit 14 calculates the amount of heat E transmitted from the heaters 24 ato 24 dto the resin Ti, by substituting the generated heat amount E Hi and the heat amount E Ri dissipated from the heaters 24 ato 24 dat the time of performing molding, and the generated heat amount E' Hi and the heat amount E' Ri dissipated from the heaters 24 ato 24 dat the time of stopping molding into the above expression (9). Then, the heater transferred heat amount calculation unit 14 uses the calculated calculation results of the heaters 24 ato 24 dto calculate the total transferred heat amount E T of all the heaters 24 ato 24 das shown in Expression (10).The shear heat amount calculation unit 15 acquires the shear heat amount based on the operation information acquired by the operation information acquisition unit 11 and the characteristic information acquired by the characteristic information acquisition unit 12 (step S 25).The plasticizing index calculation unit 16 calculates an index indicating the plasticized state based on the total amount of transferred heat E T calculated by the heater-transferred heat amount calculation unit 14 and the shear heat amount Es calculated by the shear heat amount calculation unit 15 (step S 26). The output unit 20 performs output processing based on the calculation result of the plasticizing index calculation unit 16 (step S 27). The processing of step S 28 is the same as the processing of step S 17 in FIG. 7.According to the control device 10 aof the injection molding machine 1 according to the second embodiment described above, the following advantageous effects are obtained.The control device 10 aof the injection molding machine 1 according to the present embodiment further includes the heater dissipated heat calculation unit 17 that calculates the heater dissipated heat amount from the heaters 24 ato 24 dbased on the operation information and the characteristic information, and the heater-transmitted heat amount calculation unit 14 calculates the heat amount transmitted from the heaters 24 ato 24 dto the resin based on a heat amount generated by the heaters 24 ato 24 dat the time of performing molding and a dissipated heat amount calculated by the heater-dissipated heat amount calculation unit 17, as well as the heat amount generated by the heaters 24 ato 24 dat the time of stopping molding and the dissipated heat amount calculated by the heater-dissipated heat amount calculation unit 17. With such a configuration, the amount of heat dissipated from the surface of the heaters 24 ato 24 dis compensated for, in which the difference between the time of performing shaping and the time of stopping shaping is large, and the influence on the calculation of the amount of transferred heat is large. Therefore, it is possible to calculate the amount of transferred heat more efficiently and accurately.[Third Embodiment]FIG. 12 is a functional block diagram of a control device 10 bof the injection molding machine 1 according to the third embodiment. As illustrated in FIG. 12, the control device 10 baccording to the third embodiment is different from the control device 10 of the injection molding machine 1 according to the first embodiment in that a cooling water discharged heat amount calculation unit 18 is further provided, and regarding the transferred heat amount calculation processing E, Ti, and the other configurations are the same as those of the first embodiment.In the third embodiment, the operation information acquisition unit 11 acquires the flow rate, the inlet temperature, and the outlet temperature of the cooling water in the cooling jacket 26 as the operation information in addition to the operation rates of the heaters 24 ato 24 d. In addition to the capacities of the heaters 24 ato 24 d, the characteristic information acquisition unit 12 acquires the density and specific heat of the cooling water flowing through the cooling jacket as characteristic information.Based on the operation information acquired by the operation information acquisition unit 11 and the characteristic information acquired by the characteristic information acquisition unit 12, the cooling water discharged heat amount calculation unit 18 calculates the cooling water discharged heat amount as the inner energy increase amount of the cooling water. An example of a method of calculating the amount of heat dissipated by the cooling water by the cooling water dissipated heat calculation unit 18 will be described. The amount of heat removed by the cooling water can be calculated using the following expression (11), for example. In the expression (11), E w represents the amount of heat removed by the cooling water, ρ represents the density of the cooling water, c represents the specific heat of the cooling water, Q represents the flow rate of the cooling water, T in represents the inlet temperature of the cooling water, and T out represents the outlet temperature of the cooling water. [Expression 11]The heater-transmitted heat amount calculation unit 14 calculates the amount of heat transmitted to the resin from the heaters 24 ato 24 dbased on the total amount of heat generated by the heater-generated heat amount calculation unit 13 and the cooling water-discharged heat amount calculated by the cooling water-discharged heat amount calculation unit 18. In a state where the cylinder 22 is maintained at a predetermined target temperature, the amount of heat generated by each of the heaters 24 ato 24 dat the time of performing molding is defined as E Hi and the amount of heat removed by the cooling water is defined as Ew. In addition, in a state where the cylinder 22 is maintained at a predetermined target temperature, the amount of heat generated by each of the heaters 24a to 24d at the time of stopping forming is defined as E' Hi and the amount of heat removed by the cooling water is defined as E' w. Then, the total amount of transferred heat E T can be calculated using the following expression (12). [Expression 12]According to the control device 10 of the injection molding machine 1 according to the third embodiment described above, the following advantageous effects are obtained. In the present embodiment, the control device 10 further includes the cooling water discharged heat amount calculation unit 18 that calculates the heat amount discharged by the cooling water of the cooling jacket 26 based on the operation information and the characteristic information including the information related to the cooling jacket 26 included in the injection molding machine 1, and the heater-transmitted heat amount calculation unit 14 calculates the heat amount transmitted from the heaters 24 ato 24 dto the resin based on the heat amount generated by the heaters 24 ato 24 dat the time of performing molding and the heat amount discharged by the cooling water-discharged heat amount calculation unit 18, the heat amount generated by the heaters 24 ato 24 dat the time of stopping molding and the heat amount discharged by the cooling water-discharged heat amount calculation unit 18. Even in a state where the cylinder 22 is maintained at a predetermined target temperature, the operating state of the cooling jacket 26 differs between the time of performing forming and the time of stopping forming. In this regard, according to the configuration of the third embodiment, it is possible to calculate the amount of heat transferred more accurately because the difference in the amount of heat dissipated by the cooling water between the time of performing shaping and the time of stopping shaping is compensated.[Fourth Embodiment]A control device 10 according to the fourth embodiment has the same configuration as the control device 10 of the injection molding machine 1 according to the first embodiment. In the fourth embodiment, the calculation processing of the plasticizing index calculation unit 16 is different from that of the first embodiment.In the fourth embodiment, the plasticizing index calculation unit 16 calculates the ratio between the sum of the amount of heat generated by the heaters 24 ato 24 dand the amount of shear heat, and the sum of the amount of heat transferred from the heaters and the amount of shear heat. Further, the plasticizing index calculation unit 16 acquires the energy efficiency by further calculating the ratio between a quantity of heat generated by the heaters 24 ato 24 dand the quantity of heat transmitted from the heaters 24 ato 24 d.As a plasticizing index, the output unit 20 outputs the ratio between the sum of a heat amount generated by the heaters 24 ato 24 dand the shear heat amount and the sum of the heat amount transmitted by the heaters and the shear heat amount together with the ratio between a heat amount generated by the heaters 24 ato 24 dand the heat amount transmitted by the heaters to the display device 6.According to the control device 10 of the injection molding machine 1 of the fourth embodiment, the plasticizing index calculation unit 16 calculates the ratio between the sum of a quantity of heat generated by the heaters 24 ato 24 dand the amount of shear heat and the sum of the quantity of heat transferred from the heaters 24 ato 24 dand the amount of shear heat as the plasticizing index. With such a configuration, the plasticizing energy efficiency indicating how much of the energy used by the injection molding machine 1 for plasticizing the resin is transferred to the resin is calculated. Therefore, it is possible for the user to determine the molding conditions after determining whether the efficiency is good or poor using the plasticizing energy efficiency.In the fourth embodiment, the plasticizing index calculation unit 16 calculates the ratio between the amount of heat generated by the heaters 24 ato 24 dand the amount of heat transmitted by the heaters from the heaters 24 ato 24 das a plasticizing index. With such a configuration, the energy efficiency of the heaters 24 ato 24 dthat indicates how much of the amount of heat generated by the heaters is transferred to the resin is calculated. Therefore, it is possible for the user to determine the molding condition after determining whether the efficiency is good or poor using the energy efficiency of the heaters 24 ato 24 d.[Fifth Embodiment]A control device 10 according to the fifth embodiment has the same configuration as the control device 10 of the injection molding machine 1 according to the first embodiment. In the fifth embodiment, the method of calculating the amount of heat transferred from the heaters by the heater transfer amount calculation unit 14 is different from that of the first embodiment.In the fifth embodiment, the operation information acquisition unit 11 acquires the target temperature of each control point of the cylinder 22 as the operation information. An actually measured temperature at each control point can be detected. In addition, the characteristic information acquisition unit 12 acquires a preset regression expression together with the capacities of the heaters 24 ato 24 das the characteristic information. The regression expression is acquired from, for example, a storage unit (not illustrated) of the control device 10.The heater-transmitted heat amount calculation unit 14 calculates the generated heat amount necessary for the heaters 24 ato 24 dto keep the cylinder 22 at the target temperature without using the calculation result of the heater-generated heat amount calculation unit 13. The amount of transferred heat in the forming stop state is a heat amount necessary to maintain the cylinder 22 at the target temperature. Therefore, the amount of heat generated in the forming stop state can be uniquely determined by the target temperature of the control point of the cylinder 22 in the forming stop state.In the fifth embodiment, the amount of generated heat is estimated using a regression expression indicating the relationship between the target temperature of the cylinder 22 acquired in advance and the amount of generated heat. With such a configuration, it is possible to omit the cost of obtaining the generated heat amount by actual measurement every change in the target temperature of the cylinder 22. Since heat moves in the axial direction when the target temperatures of the adjacent heaters 24 ato 24 dare different, it is desirable to use not only the target heater but also the value of the heater adjacent to that adjacent as the explanatory variable of the regression expression. Further, in the fifth embodiment, the ambient temperature around the cylinder 22 may also be added to the explanatory variable.[Sixth Embodiment]A control device 10 according to the sixth embodiment has the same configuration as the control device 10 aof the injection molding machine 1 according to the second embodiment. In the sixth embodiment, a method of calculating the amount of heat transferred from the heaters of the heater-transferred heat amount calculation unit 14 is different from that of the first embodiment.In the sixth embodiment, the operation information acquisition unit 11 acquires the target temperature of each control point of the cylinder 22 as the operation information. An actually measured temperature at each control point can be detected. In addition, the characteristic information acquisition unit 12 acquires a preset regression expression together with the capacities of the heaters 24 ato 24 das the characteristic information. The regression expression is acquired from, for example, a storage unit (not illustrated) of the control device 10.The surface temperature of the heaters 24 ato 24 din the molding stop state is uniquely determined by the target temperature of the cylinder. Therefore, in the ninth embodiment, the surface temperatures of the heaters 24 ato 24 dare estimated based on the regression expression indicating the relationship between the temperature of the cylinder 22 and the surface temperatures of the heaters 24 ato 24 d, and the amount of heat dissipated in the molding stop state is calculated. With such a configuration, it is possible to omit the operation of obtaining the dissipated heat amount by actual measurement every change in the target temperature of the cylinder 22. The ambient temperature around the cylinder may be added as an explanatory variable of the regression expression.Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, division strokes, and the like can be made to these embodiments without departing from the gist of the present disclosure or the gist of the present disclosure that arises from the contents described in the claims and their equivalents. These embodiments may also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are illustrated as an example, and are not limited thereto. The same applies to the case where numerical values or numerical expressions are used in the description of the above-described embodiment.The following follow-ups are further disclosed with respect to the above-described embodiments and modifications.(Follow-up 1)A control device (10, 10a, 10b) for an injection molding machine (1) comprising: the cylinder (22); the heater (24a to 24d) provided around the cylinder (22); and the screw (23) provided inside the cylinder (22). The control device (10, 10a, 10b) includes: the operation information acquisition unit (11) that acquires operation information related to operation of the heater (24a to 24d) and the screw (23); the characteristic information acquisition unit (12) that acquires characteristic information related to characteristics of the injection molding machine (1); the heater generated heat amount calculation unit (13) that calculates a heat amount generated by the heater (24a to 24d) based on acquired operation information and acquired characteristic information; the heater-transmitted heat amount calculation unit (14) that calculates a heat amount transmitted from the heater (24 ato 24 d) to a resin based on a heat amount generated by the heater (24 ato 24 d) at a time of performing molding in a state where the cylinder (22) is maintained at a predetermined target temperature and a heat amount generated by the heater (24 ato 24 d) at a time of stopping molding in a state where the cylinder (22) is maintained at a predetermined target temperature; a shear heat amount calculation unit (15) that calculates a shear heat amount due to rotation of the screw (23); a plasticizing index calculation unit (16) that calculates a plasticizing index based on an amount of transmitted heat calculated by the heater transmitted heat amount calculation unit (14) and a shear heat amount calculated by the shear heat amount calculation unit (15); and the output unit (20) that outputs a calculation result of the plasticizing index calculation unit (16).(Follow-up 2)The above-mentioned control device ( 10, 10 a, 10 b) for an injection molding machine ( 1) further includes the heater dissipated heat amount calculation unit ( 17) that calculates a heater dissipated heat amount from the heater ( 24 ato 24 d) based on the operation information and the characteristic information. The heater-transmitted heat amount calculation unit (14) calculates a heat amount transmitted from the heater (24a to 24d) to the resin based on a heat amount generated by the heater (24a to 24d) and a dissipated heat amount calculated by the heater-dissipated heat amount calculation unit (17) at the time of performing molding, and a heat amount generated by the heater (24a to 24d) and a dissipated heat amount calculated by the heater-dissipated heat amount calculation unit (17) at the time of stopping molding.(Lecture 3)The above-mentioned control device ( 10, 10 a, 10 b) for an injection molding machine ( 1) further includes the cooling water discharged heat amount calculation unit ( 18) that calculates a cooling water discharged heat amount based on the operation information and the characteristic information including information related to the cooling jacket included in the injection molding machine ( 1). The heater-transmitted heat amount calculation unit (14) calculates a heat amount transmitted from the heater to the resin based on a heat amount generated by the heater (24a to 24d) at the time of performing molding and a heat amount calculated by the cooling water-discharged heat amount calculation unit (18), and a heat amount generated by the heater (24a to 24d) at the time of stopping molding and a heat amount calculated by the cooling water-discharged heat amount calculation unit (18).(Follow-up 4)In the above-mentioned control device (10, 10a, 10b) for an injection molding machine (1), the plasticizing index calculation unit (16) calculates a ratio between the amount of heat transferred from the heater (24a to 24d) to the resin and the amount of shear heat as a plasticizing-related index.(After-Support 5)In the above-mentioned control device ( 10, 10 a, 10 b) for an injection molding machine ( 1), the plasticizing index calculation unit ( 16) calculates a ratio between a sum of a heat amount generated by the heater ( 24 ato 24 d) and the shear heat amount and a sum of the heat amount transmitted from the heater ( 24 ato 24 d) and the shear heat amount as the plasticizing related index.(Follow-up 6)In the above-mentioned control device ( 10, 10 a, 10 b) for an injection molding machine ( 1), the plasticizing index calculation unit ( 16) calculates a ratio between a heat amount generated by the heater ( 24 ato 24 d) and a heat amount transmitted from the heater ( 24 ato 24 d) as a plasticizing related index.List of reference characters1 Injection molding machine 10, 10 a, 10 bcontrol device 11 operation information acquisition unit 12 characteristic information acquisition unit 13 heater generation heat amount calculation unit 14 heater transfer heat amount calculation unit 15 shear heat amount calculation unit 16 plasticizing index calculation unit 17 heater dissipation heat amount calculation unit 18 cooling water removal heat amount calculation unit 20 output unitReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedJP 2001-225372

[0004]

Claims

A control device for an injection molding machine, comprising: a cylinder; at least one heater provided around the cylinder; and a screw provided inside the cylinder, wherein the control device comprises: an operation information acquisition unit that acquires operation information related to an operation of the heater and the screw; a characteristic information acquisition unit that acquires characteristic information related to characteristics of the injection molding machine; a heater generation heat amount calculation unit that calculates a heater generation heat amount based on acquired operation information and acquired characteristic information; a heater transferred heat amount calculation unit that calculates a heat amount transferred from the heater to a resin based on a heat amount generated by the heater at a time of performing molding in a state where the cylinder is maintained at a predetermined set temperature and a heat amount generated by the heater at a time of stopping molding in a state where the cylinder is maintained at a predetermined set temperature; a shear heat amount calculation unit that calculates a shear heat amount due to rotation of the screw; a plasticizing index calculation unit that calculates a plasticizing index based on an amount of transmitted heat calculated by the heat amount calculation unit from the heater and an amount of shear heat calculated by the shear heat amount calculation unit; and an output unit that outputs a calculation result of the plasticizing index calculation unit.The control device for an injection molding machine according to claim 1, further comprising a heater dissipated heat amount calculation unit that calculates a heater dissipated heat amount based on the operation information and the characteristic information, wherein the heater transferred heat amount calculation unit calculates a heater transferred heat amount to the resin based on a heater generated heat amount and a dissipated heat amount calculated by the heater dissipated heat amount calculation unit at the time of performing molding, and a heater generated heat amount and a dissipated heat amount calculated by the heater dissipated heat amount calculation unit at the time of stopping molding.The control device for an injection molding machine according to claim 1, further comprising a cooling water removed heat amount calculation unit that calculates a cooling water removed heat amount based on the operation information and the characteristic information including information related to the cooling jacket included in the injection molding machine, wherein the heating means transferred heat amount calculation unit calculates a heating amount transferred from the heating means to the resin based on a heating amount generated by the heating means at the time of performing molding and a cooling water removed heat amount calculated by the cooling water removed heat amount calculation unit, and a heating amount generated by the heating means at the time of stopping molding and a cooling water removed heat amount calculated by the cooling water removed heat amount calculation unit.The control device for an injection molding machine according to any one of claims 1 to 3, wherein the plasticizing index calculation unit calculates a ratio between the amount of heat transferred from the heater to the resin and the amount of shear heat as the plasticizing related index.The control device for an injection molding machine according to any one of claims 1 to 3, wherein the plasticizing index calculation unit calculates a ratio between a sum of a heat amount generated by the heater and the shear heat amount and a sum of the heat amount transmitted from the heater and the shear heat amount as a plasticizing related index.The control device for an injection molding machine according to claim 5, wherein the plasticizing index calculation unit calculates a ratio between a heat amount generated by the heater and a heat amount transmitted from the heater as a plasticizing related index.

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