Control device of injection molding machine

Abstract

The invention provides a technology which enables a user to properly grasp the molten state of resin in an injection molding machine so as to effectively reduce poor molding. A control device (10) of an injection molding machine (1) is provided with: an operation information acquisition unit (11) that acquires operation information relating to the operation of heaters (24a-24d); a characteristic information acquisition unit (12) that acquires characteristic information relating to characteristics of the injection molding machine (1); a heater calorific value calculation unit (13) that calculates the calorific values of the heaters (24a-24d) on the basis of the acquired operation information and characteristic information; a heater heat transfer amount calculation unit (14) that calculates the amount of heat transferred from the heaters (24a-24d) to the resin on the basis of the amount of heat generated by the heaters (24a-24d) when molding is performed in a state in which the cylinder (22) is maintained at a predetermined set temperature, and the amount of heat generated by the heaters (24a-24d) when molding is stopped in a state in which the cylinder (22) is maintained at the predetermined set temperature; a molten state determination unit (15) that determines the molten state of the resin inside the cartridge (22) on the basis of the calculation result of the heater heat transfer amount calculation unit (14); and an output unit (20) that outputs the determination result of the molten state determination unit (15).

Description

Technical Field

[0001] The present disclosure relates to a control device for an injection molding machine. Background Art

[0002] Conventionally, in a control device for an injection molding machine, in a technique of controlling the heater output so as to maintain the control point temperature of a barrel at a set temperature, heat and temperature are estimated. (For example, refer to Patent Document 1, Patent Document 2, and Patent Document 3).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: International Publication No. 2008 / 149742

[0006] Patent Document 2: International Publication No. 2019 / 177040

[0007] Patent Document 3: Japanese Unexamined Patent Application Publication No. 2010 - 241034 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] In addition, even when controlling the heater output so as to maintain the control point temperature at the set temperature, when actually measuring the resin temperature, it is sometimes different from the set temperature. For example, there are the following situations: under the condition that the heat supply to the resin is insufficient, the resin temperature is significantly lower than the set temperature, and conversely, under the condition that excessive heat is given, the resin temperature is significantly higher than the set temperature. In a state where the resin temperature significantly deviates from the set temperature, the possibility of causing molding defects and breakage of components such as a screw and a barrel becomes high.

[0010] From the viewpoint of accuracy, it is preferable to directly control the resin temperature inside the barrel rather than the control point temperature, but directly measuring and controlling the temperature of the molten resin requires strict conditions such as the strength of the barrel, the strength of the sensor, and the cost. However, when a user observes that each control point temperature of the barrel is maintained at the set value, the user will think that the resin temperature inside the barrel has become the set temperature. There is room for improvement in the prior art in enabling the user to appropriately grasp the melting state (temperature) of the resin.

[0011] The present disclosure has been made in view of the above problems, and an object thereof is to provide a technique capable of enabling a user to appropriately grasp the melting state of resin in an injection molding machine to effectively reduce molding defects.

[0012] Means for Solving the Problems

[0013] The present disclosure relates to a control device for an injection molding machine, the injection molding machine including a barrel, a heater disposed around the barrel, and a screw disposed inside the barrel. The control device includes: an operation information acquisition unit that acquires operation information related to the operation of the heater; a characteristic information acquisition unit that acquires characteristic information related to the characteristics of the injection molding machine; a heater heat generation amount calculation unit that calculates the heat generation amount of the heater based on the acquired operation information and the characteristic information; a heater heat transfer amount calculation unit that calculates the heat transfer amount from the heater to the resin based on the heat generation amount of the heater during molding execution while maintaining the barrel at a specified set temperature and the heat generation amount of the heater during molding stop while maintaining the barrel at the specified set temperature; a melting state determination unit that determines the melting state of the resin inside the barrel based on the calculation result of the heater heat transfer amount calculation unit; and an output unit that outputs the determination result of the melting state determination unit.

[0014] Effects of the Invention

[0015] According to the present disclosure, a technique can be provided that enables a user to appropriately grasp the melting state of the resin in an injection molding machine and effectively reduce molding defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram showing the structure of an injection molding machine according to the first embodiment.

[0017] Figure 2 It is a perspective view showing the heater disposed on the barrel according to the first embodiment.

[0018] Figure 3 It is a functional block diagram of a control device for an injection molding machine according to the first embodiment.

[0019] Figure 4 It is a schematic diagram for explaining the heat balance during molding execution in the first embodiment.

[0020] Figure 5 It is a schematic diagram for explaining the heat balance during molding stop in the first embodiment.

[0021] Figure 6 It is a flowchart showing an example of the process performed by the control device of the injection molding machine according to the first embodiment.

[0022] Figure 7 It is a schematic diagram for explaining the heat balance during molding execution in the second embodiment.

[0023] Figure 8 It is a schematic diagram for explaining the heat balance during molding stop in the second embodiment.

[0024] Figure 9 is a functional block diagram of a control device for an injection molding machine according to a second embodiment.

[0025] Figure 10 is a flowchart showing an example of a process performed by a control device for an injection molding machine according to a second embodiment.

[0026] Figure 11 is a graph showing the relationship between the deviation of the resin temperature from the set temperature and the heat transfer amount of the metered resin.

[0027] Figure 12 is a graph for explaining a threshold value set in the control device for determining the relationship between the resin temperature and the set temperature.

[0028] Figure 13 is a graph for explaining a threshold value set in the control device for determining the degree of deviation of the resin temperature from the set temperature.

[0029] Figure 14 is a graph showing the change in the heat transfer amount in each calculation interval.

[0030] Figure 15 is a graph showing the relationship between the heat transfer amount of the heater and the deviation between the resin temperature and the set temperature. Detailed Embodiments

[0031] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In addition, in the description after the second embodiment, the same reference numerals are assigned to the structures common to the first embodiment, and the description thereof will be appropriately omitted.

[0032] [First Embodiment]

[0033] Figure 1 is a schematic diagram showing the structure of an injection molding machine 1 according to a first embodiment. Figure 2 is a perspective view showing heaters 24a to 24d of a barrel 22 disposed in an injection molding machine 1 according to a first embodiment. The injection molding machine 1 of the present embodiment includes an injection unit 2, a mold clamping unit 3, a control device 10, and a display device 6.

[0034] The injection unit 2 is an injection device including a hopper 21, a barrel 22, a screw 23, and a cooling jacket 26. The barrel 22 is, for example, a cylindrical body. Resin stored in the hopper 21 is supplied to the barrel 22. The screw 23 is disposed inside the barrel 22 and conveys the resin to the front end of the barrel 22 by rotation. The cooling jacket 26 is a device for cooling the inside of the barrel 22 (for example, a portion on the root side inside the barrel 22), and cooling water circulates in the cooling jacket 26.

[0035] As Figure 2 shown, for example, a plurality of heaters 24a to 24d are arranged along the axial direction of the cylinder 22. Specifically, a plurality of heaters 24a to 24d are arranged from the nozzle portion 25 at the front end in the axial direction of the cylinder 22 to the base end. In addition, the number of the heaters 24a to 24d is not particularly limited.

[0036] In the present embodiment, the four heaters 24a to 24d are arranged along the axial direction so as to cover the outer periphery of the cylinder 22. The heater 24a is a front-end side heater arranged at the front end side of the nozzle portion 25. The heaters 24b to 24d are located on the upstream side of the nozzle portion 25 in the particle conveyance direction. The heater 24b is one of the front-end side heaters located closest to the nozzle portion 25. The heater 24d is located at the position farthest from the nozzle portion 25, and the heater 24c is located between the heater 24b and the heater 24d.

[0037] The cylinder 22 is heated by the heaters 24a to 24d, whereby the particles are melted. The melted particles are conveyed toward the nozzle portion 25 by the screw 23 and injected into the mold 5.

[0038] The mold clamping portion 3 is a device for clamping the mold 5. The molded product is molded by clamping the mold 5 by the mold clamping portion 3.

[0039] Next, the control device 10 will be described. Figure 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 constituted by, for example, a computer, and the computer includes memories such as a ROM (read only memory) and a RAM (random access memory) connected to each other via a bus, a CPU (control processing unit), and a communication control unit. The functions and operations of the respective functional parts of the control device 10 described below are achieved by the cooperation of the CPU, the memory, and the control program stored in the memory mounted on the above computer.

[0040] The control device 10 includes an operation information acquisition unit 11, a characteristic information acquisition unit 12, a heater calorific value calculation unit 13, a heater heat transfer calculation unit 14, a melting state determination unit 15, and an output unit 20 as functional parts.

[0041] The operation information acquisition unit 11 acquires operation information related to the operations of heaters 24a to 24d. The operation information related to heaters 24a to 24d in this embodiment is the operation rate of each of heaters 24a to 24d. The operation rate is, for example, an index of the operation state expressed by 0% to 100%. The operation rate is determined based on the output such as the voltage of heaters 24a to 24d, for example.

[0042] The characteristic information acquisition unit 12 acquires characteristic information indicating the characteristics of the injection molding machine 1. The characteristic information is, for example, the capacity of heaters 24a to 24d. The capacity of heaters 24a to 24d described here is the rated capacity such as 1500 W at 200 V.

[0043] The heater heat generation amount calculation unit 13 calculates the heat generation amounts of heaters 24a to 24d based on the acquired operation information and characteristic information. The heater heat generation amount calculation unit 13 calculates, for example, the heat generation amount per unit time of each of heaters 24a to 24d in a state where the barrel 22 is maintained at a preset set temperature. The heater heat generation amount calculation unit 13 may also correct based on the difference between the rated voltage of heaters 24a to 24d and the power supply voltage of the actual injection molding machine 1, and then calculate the heat generation amount.

[0044] An example of the calculation method for calculating the heat generation amount by the heater heat generation amount calculation unit 13 will be described. The heat generation amount can be calculated, for example, by the following formula (1). In addition, P in formula (1) Hi represents the heat generation amount per unit time, t 1 represents the start time of calculation, t 2 represents the end time of calculation, W i represents the heater capacity, and r i represents the heater operation rate.

[0045] [Equation 1]

[0046]

[0047] The heater heat transfer amount calculation unit 14 calculates the heat transfer amounts from each of heaters 24a to 24d to the resin based on the calculation result of the heater heat generation amount calculation unit 13. An example of the calculation method for calculating the heat transfer amount by the heater heat transfer amount calculation unit 14 will be described. Let the heat transfer amount per unit time from heaters 24a to 24d to the resin be P Ti . When the heat generation amount per unit time during molding while maintaining the barrel 22 at a specified set temperature is set as P Hi and the heat generation amount per unit time when stopping molding while maintaining the barrel 22 at a specified set temperature is set as P' HiWhen the heat transfer amount is the relationship of the following formula (2). As shown in the following formula (2), the heat transfer amount P can be calculated by the heat generation amount P Hi during molding execution and the heat generation amount P' Hi at the stop of molding Ti .

[0048] [Equation 2]

[0049] P Ti = P Hi - P' Hi Equation (2)

[0050] Refer to Figure 4 and Figure 5 to explain Equation (2). Figure 4 is a schematic diagram for explaining the heat balance during molding execution. Figure 5 is a schematic diagram for explaining the heat balance at the stop of molding. As Figure 4 shown, when considering the heat balance during molding execution, it can be considered that the heat generation amount P Hi for maintaining the cylinder 22 at the set temperature during molding execution is Ti obtained by adding various heat dissipations to the heat transfer amount P. Here, the various heat dissipations are the sum of the heat transfer amount to the front (nozzle part 25 side), the heat transfer amount to the rear (the opposite side of the nozzle part 25), and the heat dissipation amount from the surface of the heater 24b among the heat applied to the heater 24b.

[0051] On the other hand, when considering the heat balance at the stop of molding, different from during molding execution, the inside of the cylinder 22 becomes a stagnant state where the screw 23 stops and the resin does not flow. In this state, it can be considered that the resin temperature becomes the same as the temperature of the cylinder 22, so the heat generation amount of the heater 24b is not transferred to the resin. Therefore, as Figure 5 shown, it can be considered that the heat generation amount P' Hi for maintaining the cylinder 22 at the set temperature at the stop of molding is Hi equal to various heat dissipations. It can be considered that the various heat dissipations are also the same as during molding execution. Therefore, by subtracting the heat generation amount P' Hi from the heat generation amount P Ti , the various heat dissipations are offset, and thus the heat transfer amount P

[0052] Next, return Figure 3 to explain the molten state determination unit 15. The molten state determination unit 15 determines the molten state of the resin inside the cylinder 22 based on the calculation result of the heater heat transfer amount calculation unit 14.

[0053] The heat transfer amount P TiThere is a close relationship with the resin temperature inside the barrel 22. For example, when the resin on the upstream side in the resin conveyance direction relative to a certain heater zone does not receive sufficient heat, the temperature of the resin conveyed to this zone becomes lower than the set temperatures of the heaters 24a to 24d. In this case, a large amount of heat moves from the heaters 24a to 24d to the resin, so the heat transfer amount P Ti becomes larger. On the contrary, when the resin on the upstream side in the resin conveyance direction relative to a certain heater zone receives excessive heat, the temperature of the resin conveyed to this zone becomes higher than the set temperatures of the heaters 24a to 24d, so the heat transfer amount P Ti becomes smaller. That is, there is a negative correlation between "the deviation of the resin temperature from the set temperatures of the respective heaters 24a to 24d" and "the heat transfer amount P Ti ".

[0054] The melting state determination unit 15 of the present embodiment calculates the melting state of the resin in the form of the degree of deviation from the heater set temperature by using the correlation between "the deviation of the resin temperature from the set temperatures of the respective heaters 24a to 24d" and "the heat transfer amount P Ti ".

[0055] The output unit 20 will be described. The output unit 20 outputs the determination result of the melting state determined by the melting state determination unit 15 so that the user can grasp the melting state. In the present embodiment, a process of causing the display device 6 of the injection molding machine 1 to display the determination result of the melting state determination unit 15 is executed. In addition, the output unit 20 may be configured to output the determination result of the melting state determination unit 15 to an external computer connected to the injection molding machine 1 and different from the display device 6 of the injection molding machine 1.

[0056] The display device 6 is, for example, an output device such as a liquid crystal display or a touch panel display. In addition, it may be configured that a sound output device that outputs sound is used instead of the display device 6 to output the determination result of the melting state determination unit 15.

[0057] Next, with reference to Figure 6 the process of the process for calculating the heat transfer amount P Ti will be described. Figure 6 is a flowchart showing an example of the process performed by the control device 10 of the injection molding machine 1 according to the first embodiment.

[0058] When used to calculate the heat transfer amount P TiAt the start of the processing, the characteristic information acquisition unit 12 acquires characteristic information indicating the characteristics of the injection molding machine 1 (step S10), and the operation information acquisition unit 11 acquires the operation rate related to the operations of the heaters 24a to 24d as operation information (step S11). The operation information and the characteristic information are acquired, for example, from various sensors, a storage unit (not shown) of the control device 10, an external computer (not shown), and the like.

[0059] The heater heat generation amount calculation unit 13 calculates the heat generation amounts of the heaters 24a to 24d based on the acquired operation information and characteristic information (step S12). The heater heat generation amount calculation unit 13 calculates, for example, the heat generation amount per unit time of each of the heaters 24a to 24d in a state where the barrel 22 is maintained at a prescribed set temperature based on the operation rates of the heaters 24a to 24d and the capacities of the heaters 24a to 24d.

[0060] Next, the heater heat transfer amount calculation unit 14 calculates the heat transfer amount from the heaters 24a to 24d to the resin (step S13). The heater heat transfer amount calculation unit 14, for example, substitutes the heat generation amount P Hi of the heaters 24a to 24d during molding execution and the heat generation amount P' Hi of the heaters 24a to 24d when molding is stopped into the above formula (2) to calculate the heat transfer amount P Ti .

[0061] Next, the molten state determination unit 15 determines the molten state based on the heat transfer amount P Ti which is the calculation result of the heater heat transfer amount calculation unit 14 (step S14). The molten state determination unit 15 outputs information indicating the degree of the molten state, for example, based on conditions preset using the negative correlation between "the deviation of the resin temperature from the set temperature of each of the heaters 24a to 24d" and "the heat transfer amount P Ti ". The information indicating the degree of the molten state can be a numerical value, or can be characters, symbols, charts, pictures, or a combination thereof indicating a state corresponding to the numerical value.

[0062] When the determination result of the molten state determination unit 15 is output, the output unit 20 outputs the determination result (step S15). The output unit 20 performs, for example, a process of causing the display device 6 to display a numerical value, characters, symbols, charts, pictures, or a combination thereof which is the determination result of the molten state determination unit 15.

[0063] When the control device 10 continues the molding process after the process performed by the output unit 20 in step S15, the process returns to step S11, and the processes after step S11 are executed again (step S16: "Yes"). On the other hand, when the control device 10 detects the stop of the molding process, it executes a process for stopping the molding and ends the process flow (step S16: "No"). In addition, the continuation or stop of the molding process is determined by the control device 10 based on, for example, a user operation, whether the melting state satisfies a predetermined condition, and the like.

[0064] According to the control device 10 of the injection molding machine 1 according to the first embodiment described above, the following effects are achieved. That is, the injection molding machine 1 includes a barrel 22, heaters 24a to 24d disposed around the barrel 22, and a screw 23 disposed inside the barrel 22. Moreover, the control device 10 of the injection molding machine 1 includes: an operation information acquisition unit 11 that acquires operation information related to the operations of the heaters 24a to 24d; a characteristic information acquisition unit 12 that acquires characteristic information related to the characteristics of the injection molding machine 1; a heater heat generation amount calculation unit 13 that calculates the heat generation amounts of the heaters 24a to 24d based on the acquired operation information and characteristic information; a heater heat transfer amount calculation unit 14 that calculates the heat transfer amount from the heaters 24a to 24d to the resin based on the heat generation amounts of the heaters 24a to 24d during molding execution in a state where the barrel 22 is maintained at a predetermined set temperature and the heat generation amounts of the heaters 24a to 24d when the molding is stopped in a state where the barrel 22 is maintained at a predetermined set temperature; a melting state determination unit 15 that determines the melting state of the resin inside the barrel 22 based on the calculation result of the heater heat transfer amount calculation unit 14; and an output unit 20 that outputs the determination result of the melting state determination unit 15. Thus, through the information on the melting state output by the output unit 20, even during continuous molding, the user can accurately grasp the melting state of the resin without the need for a special sensor. Since the melting state can be grasped, it is possible to know the quality of the molding conditions and appropriately adjust the molding conditions. In addition, the information output by the output unit 20 can also be flexibly used for identifying the cause in the case of molding defects or damage to components such as the screw 23 and the barrel 22.

[0065] [Second Embodiment]

[0066] In the second embodiment, control considering the heat dissipation of the heaters 24a to 24d is performed. Refer to Figure 7 and Figure 8 to describe the heat balance considering heat dissipation in the second embodiment. Figure 7 is a schematic diagram for explaining the heat balance during molding execution in the second embodiment, Figure 8This is a schematic diagram showing the heat balance at the time of molding stop in the second embodiment.

[0067] Even when the barrel 22 is maintained at a prescribed set temperature, the operation rates indicating the operation states of the heaters 24a to 24d are different between the molding execution time and the molding stop time. If the operation rates of the heaters 24a to 24d are different, the surface temperatures of the heaters 24a to 24d are also different, and thus the heat dissipation amounts from the surfaces of the heaters 24a to 24d are different. For example, Figure 7 the heat dissipation amount P per unit time during molding execution shown Ri and Figure 8 the heat dissipation amount P' per unit time during molding stop shown Ri are different (heat dissipation amount P Ri ≠ heat dissipation amount P' Ri ). Therefore, if the difference between the heat dissipation amounts of the heaters 24a to 24d during molding execution and the heat dissipation amounts of the heaters 24a to 24d during molding stop is corrected, the heat transfer amount can be calculated more accurately.

[0068] It can be considered that the heat generation amount P during molding execution Hi is obtained by adding the heat transfer amount P Ti to the heat dissipation amount P Ri and other heat dissipations obtained by removing the heat dissipation amount P Ri from various heat dissipations. Here, the other heat dissipations are the heat transfer amounts in the forward direction (toward the nozzle portion 25 side) and the heat transfer amounts in the backward direction (the opposite side of the nozzle portion 25) in the heat transfer amount applied to the heater 24b.

[0069] The heat dissipation from the heater surface is divided into two types: convection and radiation, and the heat dissipation amount can be calculated by their total. In the second embodiment, the heater surface area, heat transfer rate, emissivity, and Stefan - Boltzmann coefficient acquired by the characteristic information acquisition unit 12 are used together with the heater surface temperature and the atmosphere temperature acquired by the operation information acquisition unit 11 to calculate the heat dissipation amount. In this calculation, the barrel 22 may be assumed to have a simple cylindrical shape for calculation. The atmosphere temperature and the temperature of the heater surface are obtained, for example, by using the detection values of a temperature sensor (not shown) or by estimating through a prescribed function.

[0070] An example of the calculation method of the heat dissipation amount will be described. The heater convective heat dissipation amount can be calculated, for example, using the following formula (3). In addition, the heater radiative heat dissipation amount can be calculated, for example, using the following formula (4). Furthermore, in the formulas, P rci represents the heater convective heat dissipation amount, T Hi represents the heater surface temperature, T C represents the atmosphere temperature, and A irepresents the heater surface area, h represents the heat transfer rate, P Rri represents the radiant heat dissipation of the heater, ε represents the emissivity, and σ represents the Stefan - Boltzmann coefficient.

[0071] [Number 3]

[0072]

[0073] [Number 4]

[0074]

[0075] Regarding the heat transfer amount in adjacent regions such as the front and rear in the axial direction to the cylinder 22 in a certain heater 24, it is considered that if the set temperature of the cylinder 22 is the same, the heat transfer amount hardly changes. In Figure 7 、 Figure 8 's example, the heat transfer amounts to the regions of heater 24a and heater 24c adjacent to the region of heater 24b are unchanged. Therefore, it can be considered that other heat dissipations after removing P Ri from various heat dissipations during molding execution are equal to other heat dissipations after removing P′ Ri from various heat dissipations during molding stop. In the second embodiment, the following formula (5) is used to calculate the heat transfer amount.

[0076] [Number 5]

[0077] P Ti =(P Hi -P′ Hi )-(P Ri -P′ Ri ) Formula (5)

[0078] Next, a specific example of the control device 10a of the second embodiment will be described. Figure 9 is a functional block diagram of the control device 10a of the injection molding machine 1 according to the second embodiment. Figure 10 is a flowchart showing an example of the process performed by the control device 10a of the injection molding machine 1 according to the second embodiment.

[0079] As Figure 9 shown, compared with the control device 10 of the injection molding machine 1 according to the first embodiment, the control device 10a according to the second embodiment is different in that the control device 10a according to the second embodiment further includes a heater heat dissipation amount calculation unit 17, and the process for calculating the heat transfer amount P Ti is different, and other structures are common to the first embodiment.

[0080] When the process for calculating the heat transfer amount P Ti starts, as Figure 10As shown, the characteristic information acquisition unit 12 acquires, as characteristic information, the shapes of the heaters 24a to 24d and constants related to the heat dissipation of the heaters 24a to 24d, in addition to the capacities of the heaters 24a to 24d (step S20).

[0081] In addition, the operation information acquisition unit 11 acquires the surface temperature of the heaters and the atmosphere temperature as operation information, in addition to the operation rates of the heaters 24a to 24d (step S21). Constants related to heat dissipation are, for example, the heat transfer rate, the emissivity, the Stefan-Boltzmann coefficient, and the like.

[0082] In addition, the heater heat generation amount calculation unit 13 calculates the heat generation amounts of the heaters 24a to 24d based on the acquired operation information and characteristic information, in the same manner as in the first embodiment (step S22).

[0083] The heater heat dissipation amount calculation unit 17 calculates the heat dissipation amounts of the respective heaters 24a to 24d 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 S23). The heat dissipation amounts of the respective heaters 24a to 24d are the heat dissipation amounts per unit time in a state where the barrel 22 is maintained at a specified set temperature.

[0084] After the heat dissipation amount calculation process performed by the heater heat dissipation amount calculation unit 17, the heater heat transfer amount calculation unit 14 calculates the heat transfer amount P from the heaters 24a to 24d to the resin Ti (step S24). The heater heat transfer amount calculation unit 14, for example, substitutes the heat generation amount P Hi and the heat dissipation amount P Ri of the heaters 24a to 24d during molding execution, and the heat generation amount P' Hi and the heat dissipation amount P' Ri of the heaters 24a to 24d when molding stops into the above formula (5) to calculate the heat transfer amount P from the heaters 24a to 24d to the resin Ti .

[0085] The molten state determination unit 15 determines the molten state based on the heat transfer amount P that is the calculation result of the heater heat transfer amount calculation unit 14 Ti and the output unit 20 performs an output process based on the determination result of the molten state determination unit 15 (step S26). The process of step S27 is the same as Figure 6 the process of step S16 of

[0086] According to the control device 10a of the injection molding machine 1 according to the second embodiment described above, the following effects are achieved.

[0087] The control device 10a of the injection molding machine 1 according to this embodiment further includes a heater heat dissipation amount calculation unit 17 that calculates the heat dissipation amounts of the heaters 24a to 24d based on the operation information and the characteristic information. The heater heat transfer amount calculation unit 14 calculates the heat transfer amount from the heaters 24a to 24d to the resin based on the calorific values of the heaters 24a to 24d during molding execution and the heat dissipation amounts calculated by the heater heat dissipation amount calculation unit 17, and the calorific values of the heaters 24a to 24d when molding stops and the heat dissipation amounts calculated by the heater heat dissipation amount calculation unit 17. Thus, the heat dissipation amount from the surfaces of the heaters 24a to 24d, which has a large difference between molding execution and molding stop and thus has a large influence on the calculation of the heat transfer amount, is corrected, so that the heat transfer amount can be calculated more efficiently and accurately.

[0088] [Third Embodiment]

[0089] The structure of the control device 10 according to the third embodiment is common to the control device 10 of the injection molding machine 1 according to the first embodiment. In the third embodiment, the determination method of the molten state determination unit 15 is different from the determination method of the first embodiment.

[0090] What is most concerned about for the user is the molten state of the resin injected into the mold 5, in other words, the molten state of the metering resin to be metered. There is a negative correlation between it and the deviation of the resin temperature at the front end of the screw 23 from the set temperature of the heater 24a or the heater 24b located on the front end side of the barrel 22.

[0091] Figure 11 It is a graph showing the relationship between the deviation of the resin temperature from the set temperature and the heat transfer amount of the metered resin. Figure 11 The horizontal axis of the graph is the heat transfer amount of the heater 24b, and the vertical axis is the experimental result indicating the degree of deviation between the resin temperature and the set temperature. This experiment was conducted using the same molding machine, screw barrel, and resin material and changing various plasticizing conditions other than the metering stroke. According to Figure 11 the fitting line, it can also be known that there is a very strong negative correlation between the heat transfer amount of the heater 24b and the deviation between the resin temperature and the set temperature. That is, when the heat transfer amount is very large, insufficient heat is received in the supply part for supplying the resin and the compression part for compressing the resin, and the resin with a metering temperature lower than the set temperature may be metered, which may lead to poor filling and molding defects. In addition, when the resin temperature is low, the viscosity of the resin is high, so a large load is applied to the components at the front end part of the screw 23, and breakage may also occur. On the contrary, when the heat transfer amount is small, excessive heat may be given, resulting in the temperature of the metered resin becoming too high and thermal deterioration occurring.

[0092] Therefore, in the third embodiment, in order to highly accurately determine the molten state of the metering resin by using the correlation regarding the metering resin, the object to be determined by the molten state determination unit 15 is set to the heater 24a of the nozzle part 25 close to the metering resin or the heater 24b on the front end side of the cylinder 22.

[0093] In addition, the object to be determined can also be selected based on the relationship between the volume of the resin to be injected (the volume of one injection) and the internal volume of the nozzle part 25, for example. When it can be determined that the volume of the resin to be injected is large due to the internal volume of the nozzle part 25, the heater 24b on the cylinder 22 side is selected. On the contrary, when it can be determined that the volume of the resin to be injected is small, the heater 24a of the nozzle part 25 is selected. The size can be determined based on a threshold set according to experience or theory, for example. In other words, only the heater located on the front end side of the cylinder 22 becomes the determination object.

[0094] According to the control device 10 of the injection molding machine 1 according to the third embodiment described above, the following effects are achieved. In the present embodiment, the molten state determination unit 15 determines the molten state of the resin inside the cylinder 22 based on the operation result of the heater heat transfer amount operation unit 14 with the heater 24a or the heater 24b located on the front end side of the cylinder 22 as the operation object. Thus, since the heat transfer amount is calculated based on the heater 24a or the heater 24b located on the front end side of the cylinder 22, the molten state of the metering resin can be grasped, and the user can appropriately and accurately adjust the molding conditions to prevent molding defects and component breakage.

[0095] [Fourth Embodiment]

[0096] The structure of the control device 10 according to the fourth embodiment is common to the control device 10 of the injection molding machine 1 according to the first embodiment. In the fourth embodiment, the molten state determination unit 15 determines the molten state based on a threshold for the operation result of the heater heat transfer amount operation unit 14. The threshold is set to determine the relationship between the resin temperature and the input set temperature. For example, when the heat transfer amount of the heaters 24a to 24d is 0 or close to 0, the resin temperature will become close to the set temperature. In addition, if the heat transfer amount is large, the resin temperature will become lower than the set temperature, and on the contrary, if the heat transfer amount is small, the resin temperature will become higher than the set temperature. Therefore, the state of the resin can be determined by appropriately setting the threshold for the heat transfer amount.

[0097] Figure 12 It is a diagram for explaining the threshold set in the control device 10 to determine the relationship between the resin temperature and the set temperature. Figure 12 The horizontal axis shown represents the heat transfer amount P Ti。In the fourth embodiment, in order to determine the relationship between the resin temperature and the set temperature, a first threshold value that is a specified upper limit value in the + direction with 0 as the reference and a second threshold value that is a specified upper limit value in the - direction with 0 as the reference are set. The first threshold value is set to a value that can be judged as the resin temperature being lower than the set temperature based on experience or theory. The second threshold value is set to a value that can be judged as the resin temperature being higher than the set temperature based on experience or theory. The first threshold value and the second threshold value are stored, for example, in a storage unit (not shown) of the control device 10 and read out by the melting state determination unit 15.

[0098] In the fourth embodiment, the melting state determination unit 15 determines that the resin temperature is equal to or approximately equal to the set temperature when the heat transfer amount P, which is the operation result of the heater heat transfer amount operation unit 14, Ti is between the first threshold value and the second threshold value. The melting state determination unit 15 determines that the resin temperature is higher than the set temperature when the heat transfer amount P Ti is a value lower than the second threshold value. On the other hand, when the heat transfer amount P Ti is a value higher than the first threshold value, it is determined that the resin temperature is lower than the set temperature.

[0099] The output unit 20 outputs the determination result derived by the melting state determination unit 15. For example, when it is determined that the resin temperature has become lower than the set temperature, the output unit 20 outputs "The resin temperature has become lower than the set temperature" to the display device 6. In addition, when it is determined that the resin temperature has become higher than the set temperature, the output unit 20 outputs "The resin temperature has become higher" to the display device 6. In addition, it may be that when it is determined that the resin temperature is equal to the set temperature, the output unit 20 displays information such as "The resin temperature is consistent with the set temperature" on the display device 6. In addition, the output unit 20 may also cause the display device 6 to display Figure 12 the shown graph, and an image obtained by adding a symbol indicating the position corresponding to the current operation result to the graph shown in Figure 12 .

[0100] In addition, in the description of the fourth embodiment, two threshold values, the first threshold value and the second threshold value, are set and the determination result is three, but it is not limited to this. For example, the following structure may also be adopted: One threshold value is set to determine whether the resin temperature is high or low. In addition, a structure in which three or more threshold values are set to more finely determine the melting state may also be adopted.

[0101] The control device 10 of the injection molding machine 1 according to the fourth embodiment described above has the following effects. In the present embodiment, the molten state determination unit 15 determines the molten state based on a threshold value that is a reference for determining the relationship between the resin temperature and the input set temperature, and the calculation result of the heater heat transfer amount calculation unit 14. Thus, the user can grasp the relationship between the resin temperature and the set temperature during molding execution, and can more easily grasp the molten state of the resin.

[0102] [Fifth Embodiment]

[0103] The structure of the control device 10 according to the fifth embodiment is common to the control device 10 of the injection molding machine 1 according to the first embodiment. In the fifth embodiment, the molten state determination unit 15 determines the molten state based on a threshold value for the calculation result of the heater heat transfer amount calculation unit 14. The threshold value is set to determine whether the resin temperature deviates too much from the input set temperature. For example, when the heat transfer amount of the heaters 24a to 24d is too large, the resin temperature becomes too low beyond the normal range. On the contrary, when the heat transfer amount is too small, the resin temperature becomes too high beyond the normal range. When the heat transfer amount is outside the normal range like this, it cannot be considered that appropriate molding conditions are maintained.

[0104] Figure 13 It is a diagram for explaining the threshold value set in the control device for determining the degree of deviation of the resin temperature from the set temperature. Figure 13 The horizontal axis shown represents the heat transfer amount P Ti . In the fifth embodiment, in order to determine whether the resin temperature is within the normal range, a first threshold value that is a specified upper limit value in the + direction with 0 as the reference, and a second threshold value that is a specified upper limit value in the - direction with 0 as the reference are set. The first threshold value and the second threshold value are set to values that can judge the normal range based on experience or theory. The first threshold value and the second threshold value are stored in a storage unit (not shown) of the control device 10, for example, and read out by the molten state determination unit 15.

[0105] In the fifth embodiment, the molten state determination unit 15 determines that the resin temperature is within the normal range when the heat transfer amount P Ti as the calculation result of the heater heat transfer amount calculation unit 14 is between the first threshold value and the second threshold value. The molten state determination unit 15 determines that the resin temperature deviates from the set temperature by being significantly higher than the set temperature when the heat transfer amount P Ti is a value lower than the second threshold value. On the other hand, when the heat transfer amount P Ti is a value higher than the first threshold value, it is determined that the resin temperature deviates from the set temperature by being significantly lower than the set temperature.

[0106] The output unit 20 outputs the determination result derived by the melting state determination unit 15. For example, when the resin temperature deviates downward from the normal range, the output unit 20 outputs a warning message such as "The resin temperature has become too low compared to the set temperature" to the display device 6. In addition, when the resin temperature deviates upward from the normal range, a warning message such as "The resin temperature has become too high" is output to the display device 6. In addition, it may be that when the resin temperature is within the normal range, the output unit 20 outputs information such as "The resin temperature is normal" to the display device 6. In addition, the output unit 20 may also cause the display device 6 to display Figure 13 the figure shown in Figure 13 the figure shown, and an image obtained by adding a symbol indicating the position corresponding to the current operation result to the figure.

[0107] In addition, in the description of the fifth embodiment, two thresholds, namely the first threshold and the second threshold, are set and the determination result is set to three, but it is not limited to this. For example, the threshold may be set to one, or three or more thresholds may be set to more finely determine the melting state structure.

[0108] According to the control device 10 of the injection molding machine 1 according to the fifth embodiment described above, the following effects are achieved. In the present embodiment, the melting state determination unit 15 determines the melting state based on the threshold value that is the reference for determining whether the resin temperature deviates too much from the set temperature and the operation result of the heater heat transfer amount calculation unit 14. When it is determined that the resin temperature deviates too much from the set temperature, the output unit outputs a warning message. Thereby, the user can quickly and easily grasp whether the melting state of the resin has become inappropriate, and can change the molding conditions to more appropriate metering conditions when it is inappropriate.

[0109] [Sixth Embodiment]

[0110] The structure of the control device 10 according to the sixth embodiment is common to the control device 10 of the injection molding machine 1 according to the first embodiment. In the sixth embodiment, the melting state determination unit 15 compares the results of the heater heat transfer amount calculation unit 14 in different operation intervals to determine how the resin temperature has changed. In addition, in the following description, the operation interval is determined according to the number of injections.

[0111] The melting state determination unit 15 compares the heat transfer amounts that are the operation results of the heater heat transfer amount calculation unit 14 for each interval, and calculates the difference in heat transfer amount for each interval. Based on the difference in heat transfer amount for each interval and a preset threshold value, it is determined whether the resin temperature in different operation intervals has changed, such as "no change", "temperature rise", or "temperature drop". The threshold value is set based on theory or experience, for example, and is a determination reference for whether a change has occurred, and is stored in a storage unit (not shown) of the control device 10.

[0112] Figure 14 is a graph showing the change in heat transfer amount for each operation section. In Figure 14 the graph, the horizontal axis represents the number of injections, and the vertical axis represents the heat transfer amount. In this example, the average value of the heat transfer amount in section 1 is A, the average value of the heat transfer amount in section 2 is B, and the average value of the heat transfer amount in section 3 is C. A, B, and C are numerical values, and the magnitude relationship is A > C > B. In addition, the average value mentioned here is, for example, a representative value of the heat transfer amount for each injection in the same operation section.

[0113] In Figure 14 the example, the change in resin temperature is determined for section 2 and section 3. For section 2, A > B holds for the difference in the degree of change, so the melting state determination unit 15 determines the melting state as "temperature rise" indicating that the resin temperature has risen compared to section 1. For section 3 as well, C < B holds for the difference in the degree of change, so the melting state determination unit 15 determines the melting state as "temperature drop" indicating that the resin temperature has dropped compared to section 2.

[0114] The output unit 20 outputs the determination result derived by the melting state determination unit 15. For example, when it is determined that the resin temperature has risen, the output unit 20 outputs information indicating "temperature rise" to the display device 6. In addition, when it is determined that the resin temperature has dropped, information indicating "temperature drop" is output to the display device 6. In addition, it may be that when the resin temperature does not exceed the threshold value and it is determined that there is no change, the output unit 20 outputs information such as "no change" to the display device 6. In addition, the output unit 20 may also cause Figure 14 the graph shown and the information indicating the operation result to be displayed on the display device 6.

[0115] In addition, in the description of the sixth embodiment, it is assumed to be a structure that selects one determination result from three determination results, but it is not limited to this. For example, it may be determined whether a temperature change has occurred, or it may be a structure that sets a lot of threshold values and selects one determination result from four or more determination results.

[0116] According to the control device 10 of the injection molding machine 1 according to the sixth embodiment described above, the following effects are achieved. In the present embodiment, the melting state determination unit 15 compares the operation results of the heater heat transfer amount calculation unit 14 in different operation sections and determines the change in the resin temperature in the operation section based on the comparison result. As a result, the user can easily grasp conditions such as molding conditions and the temperature change of the resin when the molding state changes, and can perform effective adjustment of the molding conditions.

[0117] [Seventh Embodiment]

[0118] The control device 10 according to the seventh embodiment has the same structure as the control device 10 of the injection molding machine 1 according to the first embodiment. In the seventh embodiment, the molten state determination unit 15 uses the correlation between the heat transfer amount of the heaters 24a to 24d obtained in advance and the deviation of the resin temperature from the set temperature, and converts the heat transfer amount, which is the operation result of the heater heat transfer amount calculation unit 14, into the deviation (relative value) between the resin temperature and the set temperature.

[0119] Figure 15 It is a diagram showing the relationship between the heat transfer amounts of the heaters 24a to 24d and the deviation between the resin temperature and the set temperature. In Figure 15 the diagram, the horizontal axis represents the heat transfer amount of the heater, and the vertical axis represents the degree of deviation between the resin temperature and the set temperature. As Figure 15 shown, a regression formula representing the relationship between the heat transfer amount and the deviation between the resin temperature and the set temperature is derived in advance, and this regression formula is stored in a storage unit (not shown) of the control device 10 or the like.

[0120] The molten state determination unit 15 substitutes the heat transfer amount into the pre-set regression formula to calculate the degree of deviation representing the deviation between the resin temperature and the set temperature. In addition, the molten state determination unit 15 can also use the set temperatures of the heaters 24a to 24d to convert it into the absolute value of the resin temperature.

[0121] The output unit 20 outputs the determination result derived by the molten state determination unit 15. The output unit 20 outputs, for example, a numerical value representing the degree of deviation between the resin temperature and the set temperature, and the resin temperature based on the degree of deviation as the determination result of the molten state determination unit 15. In addition, the output unit 20 can also cause Figure 15 the diagram shown, the regression formula, and the information representing the operation result to be displayed on the display device 6 together.

[0122] According to the control device 10 of the injection molding machine 1 according to the seventh embodiment described above, the following effects are achieved. In the present embodiment, the molten state determination unit 15 outputs at least either the deviation amount between the resin temperature and the set temperature and the resin temperature (absolute value) calculated based on the deviation amount as the determination result based on the regression formula for pre-deriving the deviation degree between the resin temperature and the set temperature and the operation result of the heater heat transfer amount calculation unit. Thus, the user can quantitatively grasp the molten state of the resin.

[0123] [Eighth Embodiment]

[0124] The control device 10 according to the eighth embodiment has the same structure as the control device 10 of the injection molding machine 1 according to the first embodiment. In the eighth embodiment, the method for calculating the heat transfer amount of the heater heat transfer amount calculation unit 14 is different from that in the first embodiment.

[0125] In the eighth embodiment, the operation information acquisition unit 11 acquires the set temperatures of the respective control points of the cylinder 22 as operation information. It is also possible to acquire the measured temperatures at the respective control points. Further, the characteristic information acquisition unit 12 acquires a preset regression formula together with the capacities of the heaters 24a to 24d as characteristic information. The regression formula is acquired, for example, from a storage unit (not shown) of the control device 10.

[0126] The heater heat transfer amount calculation unit 14 calculates the heat generation amounts required for the heaters 24a to 24d to maintain the cylinder 22 at the set temperature without using the calculation results of the heater heat generation amount calculation unit 13. The heat generation amount in the molding stop state is the heat required to maintain the cylinder 22 at the set temperature. Therefore, the heat generation amount in the molding stop state can be uniquely determined from the set temperatures of the control points of the cylinder 22 in the molding stop state.

[0127] In the eighth embodiment, the heat transfer amount is estimated using a regression formula that represents the relationship between the set temperature of the cylinder 22 and the heat generation amount, which has been acquired in advance. Thereby, the labor of obtaining the heat transfer amount by measurement every time the set temperature of the cylinder 22 changes can be omitted. Further, when the set temperatures of the adjacent heaters 24a to 24d are different, heat moves in the axial direction. Therefore, it is desirable to use not only the value of the target heater but also the values of the adjacent heaters as explanatory variables in the regression formula. Also, in the eighth embodiment, the ambient temperature around the cylinder 22 may be added as an explanatory variable.

[0128] [Ninth Embodiment]

[0129] The structure of the control device 10 according to the ninth embodiment is common to the control device 10a of the injection molding machine 1 according to the second embodiment. In the ninth embodiment, the method for calculating the heat transfer amount by the heater heat transfer amount calculation unit 14 is different from that of the first embodiment.

[0130] In the ninth embodiment, the operation information acquisition unit 11 acquires the set temperatures of the respective control points of the cylinder 22 as operation information. It is also possible to acquire the measured temperatures at the respective control points. Further, the characteristic information acquisition unit 12 acquires a preset regression formula together with the capacities of the heaters 24a to 24d as characteristic information. The regression formula is acquired, for example, from a storage unit (not shown) of the control device 10.

[0131] The surface temperatures of heaters 24a to 24d in the molding stop state are uniquely determined according to the set temperature of the barrel. Therefore, in the ninth embodiment, the surface temperatures of heaters 24a to 24d are estimated based on a regression formula representing the relationship between the temperature of barrel 22 and the surface temperatures of heaters 24a to 24d, and the heat dissipation amount in the molding stop state is calculated. Thereby, the effort of obtaining the heat dissipation amount by actual measurement every time the set temperature of barrel 22 changes can be omitted. In addition, the ambient temperature around the barrel may be added as an explanatory variable of the regression formula.

[0132] The present disclosure has been described in detail, but the present disclosure is not limited to the above-described embodiments. These embodiments can be variously added, replaced, changed, partially deleted, etc. within the scope not departing from the gist of the present disclosure, or within the scope not departing from the gist of the present disclosure derived from the content described in the claims and its equivalents. In addition, these embodiments can also be implemented in a combined manner. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as an example and are not limited thereto. In addition, the same applies to the case where numerical values or mathematical formulas are used in the description of the above-described embodiments.

[0133] Regarding the above-described embodiments and modification examples, the following remarks are also disclosed.

[0134] (Remark 1)

[0135] A control device (10, 10a) of an injection molding machine (1), the injection molding machine (1) including a barrel (22), heaters (24a to 24d) disposed around the barrel (22), and a screw (23) disposed inside the barrel (22), the control device (10, 10a) of the injection molding machine (1) including:

[0136] An operation information acquisition unit (11) that acquires operation information related to the operation of the heaters (24a to 24d);

[0137] A characteristic information acquisition unit (12) that acquires characteristic information related to the characteristics of the injection molding machine (1);

[0138] A heater heat generation amount calculation unit (13) that calculates the heat generation amount of the heaters (24a to 24d) based on the acquired operation information and characteristic information;

[0139] A heater heat transfer amount calculation unit (14) that calculates the heat transfer amount from the heaters (24a to 24d) to the resin based on the calorific value of the heaters (24a to 24d) during molding execution while maintaining the barrel (22) at a specified set temperature, and the calorific value of the heaters (24a to 24d) when molding stops while maintaining the barrel (22) at the specified set temperature;

[0140] A molten state determination unit (15) that determines the molten state of the resin inside the barrel based on the calculation result of the heater heat transfer amount calculation unit (14); and

[0141] An output unit (20) that outputs the determination result of the molten state determination unit (15).

[0142] (Supplementary Note 2)

[0143] In the control devices (10, 10a) of the above injection molding machine (1),

[0144] A heater heat dissipation amount calculation unit (17) is further provided, and the heater heat dissipation amount calculation unit (17) calculates the heat dissipation amount of the heaters (24a to 24d) based on the operation information and the characteristic information.

[0145] The heater heat transfer amount calculation unit (14) calculates the heat transfer amount from the heaters (24a to 24d) to the resin based on the calorific value of the heaters (24a to 24d) during molding execution and the heat dissipation amount calculated by the heater heat dissipation amount calculation unit (17), and the calorific value of the heaters (24a to 24d) when molding stops and the heat dissipation amount calculated by the heater heat dissipation amount calculation unit (17).

[0146] (Supplementary Note 3)

[0147] In the control devices (10, 10a) of the above injection molding machine (1),

[0148] The molten state determination unit (15) determines the molten state of the resin inside the barrel based on the calculation result of the heater heat transfer amount calculation unit (14) with the heaters (24a to 24d) located on the front end side of the barrel as the calculation object.

[0149] (Supplementary Note 4)

[0150] In the control devices (10, 10a) of the above injection molding machine (1),

[0151] The molten state determination unit (15) determines the molten state based on a threshold value that is a reference for determining the relationship between the resin temperature and the input set temperature, and the calculation result of the heater heat transfer amount calculation unit (14).

[0152] (Supplementary Note 5)

[0153] In the control devices (10, 10a) of the injection molding machine (1) described above,

[0154] The molten state determination unit (15) determines the molten state based on a threshold value that is a reference for determining whether the resin temperature deviates too much from the set temperature, and the calculation result of the heater heat transfer amount calculation unit (14).

[0155] When it is determined that the resin temperature deviates too much from the set temperature, the output unit (20) outputs a warning message.

[0156] (Supplementary Note 6)

[0157] In the control devices (10, 10a) of the injection molding machine (1) described above,

[0158] The molten state determination unit (15) compares the calculation results of the heater heat transfer amount calculation unit (14) in different calculation intervals, and determines the change in the resin temperature in the calculation interval based on the comparison result.

[0159] (Supplementary Note 7)

[0160] In the control devices (10, 10a) of the injection molding machine (1) described above,

[0161] The molten state determination unit (15) outputs at least one of the deviation amount between the resin temperature and the set temperature and the resin temperature calculated based on the deviation amount as a determination result, based on a regression formula for previously deriving the deviation degree between the resin temperature and the set temperature, and the calculation result of the heater heat transfer amount calculation unit (14).

[0162] Explanation of Reference Numerals

[0163] 1: Injection molding machine; 10, 10a: Control devices; 11: Action information acquisition unit; 12: Characteristic information acquisition unit; 13: Heater heat generation amount calculation unit; 14: Heater heat transfer amount calculation unit; 15: Molten state determination unit; 17: Heater heat dissipation amount calculation unit; 20: Output unit.

Claims

1. A control device for an injection molding machine, the injection molding machine having a barrel, a heater disposed around the barrel, and a screw disposed inside the barrel, the control device for the injection molding machine comprising: An operation information acquisition unit that acquires operation information related to the operation of the heater; A characteristic information acquisition unit that acquires characteristic information related to the characteristics of the injection molding machine; A heater heat generation amount calculation unit that calculates the heat generation amount of the heater based on the acquired operation information and characteristic information; A heater heat transfer amount calculation unit that calculates the heat transfer amount from the heater to the resin based on the heat generation amount of the heater during molding execution in a state where the barrel is maintained at a specified set temperature and the heat generation amount of the heater during molding stop in a state where the barrel is maintained at the specified set temperature; A melting state determination unit that determines the melting state of the resin inside the barrel based on the calculation result of the heater heat transfer amount calculation unit; and An output unit that outputs the determination result of the melting state determination unit.

2. The control device for an injection molding machine according to claim 1, wherein, It further includes a heater heat dissipation amount calculation unit that calculates the heat dissipation amount of the heater based on the operation information and the characteristic information, The heater heat transfer amount calculation unit calculates the heat transfer amount from the heater to the resin based on the heat generation amount of the heater during molding execution and the heat dissipation amount calculated by the heater heat dissipation amount calculation unit, and the heat generation amount of the heater during molding stop and the heat dissipation amount calculated by the heater heat dissipation amount calculation unit.

3. The control device for an injection molding machine according to claim 1 or 2, wherein, The melting state determination unit determines the melting state of the resin inside the barrel based on the calculation result of the heater heat transfer amount calculation unit with the heater located on the front end side of the barrel as the calculation object.

4. The control device for an injection molding machine according to any one of claims 1 to 3, wherein, The melting state determination unit determines the melting state based on a threshold value that is a reference for determining the relationship between the resin temperature and the input set temperature and the calculation result of the heater heat transfer amount calculation unit.

5. The control device for an injection molding machine according to any one of claims 1 to 3, wherein, The melting state determination unit determines the melting state based on a threshold value that is a reference for determining whether the resin temperature deviates too much from the set temperature and the calculation result of the heater heat transfer amount calculation unit, When it is determined that the resin temperature deviates too much from the set temperature, the output unit outputs a warning message.

6. The control device for an injection molding machine according to any one of claims 1 to 3, wherein, The melting state determination unit compares the calculation results of the heater heat transfer amount calculation unit in different calculation ranges and determines the change in the resin temperature in the calculation range based on the comparison result.

7. The control device for an injection molding machine according to any one of claims 1 to 3, wherein, The molten state determination unit outputs, as a determination result, at least one of the deviation amount between the resin temperature and the set temperature and the resin temperature calculated based on the deviation amount, based on a regression formula for previously deriving the degree of deviation between the resin temperature and the set temperature and the calculation result of the heater heat transfer amount calculation unit.

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