Control device and program for injection molding machine

Abstract

Provided is a control device and program for an injection molding machine that can improve the accuracy of an estimated surface temperature of a heater. A control device for an injection molding machine that has a cylinder and a heater disposed around the cylinder, the control device for the injection molding machine being configured to estimate a surface temperature of the heater at a prescribed time, the control device for the injection molding machine including: an operation information acquisition section that acquires a heater output of the heater and a set temperature of the heater in a prescribed period immediately before the prescribed time as operation information; a surface temperature acquisition section that acquires a surface temperature of the heater in the prescribed period included in the acquired operation information; an actual performance information acquisition section that acquires an actual performance of a change in a ratio of the surface temperature to the set temperature of the heater with respect to a change in the heater output of the heater as actual performance information; and an estimation section that estimates the surface temperature of the heater at the prescribed time based on the operation information, the actual performance information, and the acquired surface temperature.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a control device and a program of an injection molding machine. BACKGROUND

[0002] Conventionally, an injection molding machine is known which melts pellets added to a hopper and injects the pellets into a mold. A heater is arranged on the outer periphery of a cylinder of the injection molding machine. The cylinder is heated by the heater to melt the pellets.

[0003] It is useful to monitor the surface temperature of the heater to monitor the state of the heater and to calculate the amount of heat emission. Therefore, measures such as providing a temperature measuring sensor on the surface of the heater, performing temperature measurement by thermography, and estimating the surface temperature using an equation are implemented. In addition, as the estimation of the surface temperature using an equation, for example, a display device is proposed which calculates the surface temperature of the heater based on an operation command value of the heater and a temperature detection value from a temperature sensor (for example, refer to Patent Literature 1).

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: International Publication No. 2008 / 149742 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] In the estimation of the surface temperature using an equation, the temperature of an arbitrary position in the axial direction and the radial direction of the cylinder is estimated using the temperature of a detection point obtained by an additional sensor or the like of a temperature control point. On the other hand, in an actual cylinder, there are holes for sensors, openings, and the like. Therefore, the surface temperature of the cylinder does not become a uniform distribution. Thus, an error can occur between the estimated temperature and the actual temperature. Therefore, it is preferable if the accuracy of the estimated surface temperature of the heater can be improved.

[0009] SOLUTION TO THE PROBLEM

[0010] (1) The present disclosure relates to a control device of an injection molding machine having a cylinder and a heater arranged around the cylinder, the control device of the injection molding machine being configured to estimate a surface temperature of the heater at a prescribed time, the control device of the injection molding machine including: an operation information acquisition section configured to acquire a heater output of the heater and a set temperature of the heater in a prescribed period immediately before the prescribed time as operation information; a surface temperature acquisition section configured to acquire a surface temperature of the heater in the prescribed period included in the acquired operation information; an achievement information acquisition section configured to acquire an achievement of a change in a ratio of the surface temperature to the set temperature of the heater with respect to a change in the heater output of the heater as achievement information; and an estimation section configured to estimate the surface temperature of the heater at the prescribed time based on the operation information, the achievement information, and the acquired surface temperature.

[0011] (2) In addition, the present disclosure relates to a program that causes a computer to function as a control device of an injection molding machine having a cylinder and a heater arranged around the cylinder, the control device of the injection molding machine being configured to estimate a surface temperature of the heater at a prescribed time, the program causing the computer to function as: an operation information acquisition section configured to acquire a heater output of the heater and a set temperature of the heater in a prescribed period immediately before the prescribed time as operation information; a surface temperature acquisition section configured to acquire a surface temperature of the heater in the prescribed period included in the acquired operation information; an achievement information acquisition section configured to acquire an achievement of a change in a ratio of the surface temperature to the set temperature of the heater with respect to a change in the heater output of the heater as achievement information; and an estimation section configured to estimate the surface temperature of the heater at the prescribed time based on the operation information, the achievement information, and the acquired surface temperature.

[0012] Effects of the Invention

[0013] According to the present disclosure, it is possible to provide a control device of an injection molding machine and a program that can improve the accuracy of an estimated surface temperature of a heater. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a schematic view that shows an injection molding machine including a control device according to one embodiment of the present disclosure.

[0015] Figure 2 is a table that shows an example of achievement information learned by the control device according to one embodiment.

[0016] Figure 3is a block diagram showing the structure of a control device of one embodiment.

[0017] Figure 4 is a summary view of an example of action information of a control device of one embodiment.

[0018] Figure 5 is a summary view of an example of achievement information of a control device of one embodiment.

[0019] Figure 6 is a screen view showing a screen displayed on a display portion of a control device of one embodiment.

[0020] Figure 7 is a flowchart showing the flow of actions of a control device of one embodiment.

[0021] Figure 8 is a screen view showing a screen displayed on a display portion involved in a control device of a modification example.

[0022] Figure 9 is a screen view showing a screen displayed on a display portion of a control device of another modification example.

[0023] Figure 10 is a screen view showing a screen displayed on a display portion of a control device of another modification example. DETAILED DESCRIPTION

[0024] One embodiment of the present disclosure will be described below with reference to Figures 1 to 10 a control device 1 and a program of an injection molding machine.

[0025] First, an injection molding machine 10 controlled by the control device 1 of the present embodiment will be described.

[0026] The injection molding machine 10 is a device that performs molding by injecting a molten pellet into a mold (not shown). As shown in Figure 1 , the injection molding machine 10 includes, for example, a cylinder 101, a heater 102, and a safety cover 103.

[0027] The cylinder 101 is, for example, a cylindrical body. One end of the cylinder 101 in the axial direction is tapered toward the end. The inside of the cylinder 101 has a screw (not shown) along the axial direction. The screw moves the molten pellet toward one end side of the cylinder 101 while stirring it.

[0028] The heater 102 is arranged around the cylinder 101. For example, a plurality of heaters 102 are arranged in the axial direction of the cylinder 101. Specifically, the plurality of heaters 102 are arranged from the nozzle portion at the axial front end of the cylinder 101 to the base end. In the present embodiment, five heaters 102 are arranged in the axial direction, and each heater 102 is arranged so as to cover the outer periphery of the cylinder 101. The heater 102, for example, heats the cylinder 101 to 200 degrees or more.

[0029] The safety cover 103 is a concave body arranged around the heater 102. The safety cover 103 is arranged in order to avoid contact with the heater 102, which becomes a high temperature.

[0030] According to the above injection molding machine 10, the pellets are melted in the inside of the cylinder 101 heated to 200 degrees or more by the heater 102. The screw injects the melted pellets from one end of the cylinder 101 into a mold. Thus, the injection molding machine 10, for example, performs molding of a plastic product.

[0031] Here, the safety cover 103 is arranged around the heater 102, and thus the surface temperature of the heater 102 is not easily measured directly from the outside. On the other hand, it is known that there is a correlation between the actual surface temperature of the heater 102, the set temperature set to the heater 102, and the heater output of the heater 102. Specifically, it is known that there is a correlation between the ratio of the surface temperature of the heater 102 to the set temperature and the average heater output of the heater 102. For example, as shown in Figure 2 the set temperature of the heater 102 and the rotation speed of the screw are set to (1) 220 degrees, 50 rpm; (2) 180 degrees, 100 rpm; and (3) 180 degrees, 50 rpm. As a result, the surface temperature / set temperature is 1.19, 0.792, and 0.919, respectively, and the average heater output is 46.6%, 6.62%, and 14.5%, respectively. As a result, the correlation coefficient of the surface temperature / set temperature and the heater output is 0.991. Thus, it is known that there is a strong correlation between the surface temperature / set temperature and the heater output. Furthermore, in the following embodiments, the heater output is described as an instruction value from a controller (not shown) that controls the heater 102, which indicates the amount of operation of the heater 102. In addition, as an example, the controller determines the instruction value based on the detection value of the temperature control point.

[0032] The control device 1 of the injection molding machine 10 according to the embodiment below uses the above-described correlation to estimate the surface temperature of the heater 102 from the outside. Thus, the control device 1 of the injection molding machine 10 according to the embodiment below can estimate the surface temperature of the heater 102 with higher precision than when the surface temperature of the heater 102 is estimated using an equation from a temperature control point and a detection point of an additional sensor or the like. Further, in the embodiment below, "in operation" refers to the instant at which the injection molding machine 10 is now operating. In addition, in the embodiment below, "a prescribed time" refers to the time at which the surface temperature of the heater 102 is to be estimated.

[0033] Next, the control device 1 of the injection molding machine 10 according to one embodiment of the present disclosure will be described with reference to Figures 1 to 7

[0034] The control device 1 is a device that controls the injection molding machine 10. Specifically, the control device 1 is a device that controls the molding conditions of the injection molding machine 10. As shown in Figure 1 , the control device 1 is connected to the injection molding machine 10, for example. The control device 1 specifies and controls the molding conditions of the injection molding machine 10, such as the speed, pressure, temperature of the cylinder 101, mold temperature, and injection amount of the molten pellets. The control device 1 in the present embodiment can also estimate the surface temperature of the heater 102 at a prescribed time. As shown in Figure 3 , the control device 1 includes an operation information storage section 11, an operation information acquisition section 12, an actual performance information storage section 13, an actual performance information acquisition section 14, a surface temperature acquisition section 15, a calculation section 16, an estimation section 17, an output section 18, and an output control section 19.

[0035] The operation information storage section 11 is a recording medium such as a hard disk, for example. The operation information storage section 11 stores operation information related to the set temperature of the heater 102 of the injection molding machine 10 and the heater output of the heater 102 in operation. In addition, the operation information storage section 11 stores the content of the instruction related to the operation of the injection molding machine 10 as operation information, for example. The operation information storage section 11 stores the above-described molding conditions as operation information, for example. As shown in Figure 4 , the operation information storage section 11 sets 0 at the start of the operation and T at the prescribed time, for example, and stores the heater outputs y0, y1,... yT-1 every sampling period t1 (s) until t_T-1 immediately before the prescribed time. In addition, the operation information storage section 11 stores S (°C) as the set temperature.

[0036] ​The operation information acquisition section 12 is realized by, for example, the CPU operating. The operation information acquisition section 12 acquires the heater output of the heater and the set temperature of the heater in a prescribed period immediately before a prescribed time as operation information. In the present embodiment, the operation information acquisition section 12 acquires the operation information from the operation information holding section 11. The operation information acquisition section 12, for example, acquires the heater output of the heater 102 and the set temperature of the heater 102 in a period from the start of the operation of the injection molding machine 10 to immediately before the prescribed time as operation information. The operation information acquisition section 12, for example, acquires the heater output expressed in a predetermined sampling period until immediately before the prescribed time.

[0037] The performance information holding section 13 is, for example, a recording medium such as a hard disk. The performance information holding section 13 holds the performance of the ratio of the surface temperature of the heater 102 to the set temperature in relation to the progress of the heater output of the heater 102 as performance information. The performance information holding section 13, for example, holds the progress of the heater output of the heater 102 measured in advance as input data, and holds the progress of the ratio of the surface temperature of the heater 102 to the set temperature of the heater 102 (surface temperature / set temperature) measured at the same time as performance information. The performance information holding section 13 holds the performance information obtained in advance by learning the teaching data with the heater output as input. The performance information holding section 13, for example, can also hold the performance information obtained by learning the relationship between the heater output and the surface temperature as shown in FIG. 6 using a temperature sensor (not shown) that comes into contact with the surface of the heater 102 in advance. The performance information holding section 13, for example, holds a plurality of performances as performance information. As shown in FIG. 7, the performance information holding section 13, for example, holds the performance information with the measurement number set to M (M is a natural number), the measurement start time (operation start time) set to 0, and the time at which the heater output is acquired set to t_N (N is a natural number) for each measured performance. Figure 2 Figure 5 The performance information holding section 13 is, for example, a recording medium such as a hard disk. The performance information holding section 13 holds the performance of the ratio of the surface temperature of the heater 102 to the set temperature in relation to the progress of the heater output of the heater 102 as performance information. The performance information holding section 13, for example, holds the progress of the heater output of the heater 102 measured in advance as input data, and holds the progress of the ratio of the surface temperature of the heater 102 to the set temperature of the heater 102 (surface temperature / set temperature) measured at the same time as performance information. The performance information holding section 13 holds the performance information obtained in advance by learning the teaching data with the heater output as input. The performance information holding section 13, for example, can also hold the performance information obtained by learning the relationship between the heater output and the surface temperature as shown in FIG. 6 using a temperature sensor (not shown) that comes into contact with the surface of the heater 102 in advance. The performance information holding section 13, for example, holds a plurality of performances as performance information. As shown in FIG. 7, the performance information holding section 13, for example, holds the performance information with the measurement number set to M (M is a natural number), the measurement start time (operation start time) set to 0, and the time at which the heater output is acquired set to t_N (N is a natural number) for each measured performance.

[0038] The performance information acquisition section 14 is realized by, for example, the CPU operating. The performance information acquisition section 14 acquires the performance information from the performance information holding section 13. The performance information acquisition section 14, for example, acquires the performance of the ratio of the surface temperature of the heater 102 to the set temperature in relation to the progress of the heater output of the heater 102 as performance information. Specifically, the performance information acquisition section 14 acquires the ratio of the past set temperature to the past surface temperature (surface temperature / set temperature) as performance information for each past heater output.

[0039] ​The surface temperature acquisition section 15 is realized by, for example, a CPU acting. The surface temperature acquisition section 15 acquires the surface temperature of the heater 102 in a prescribed period included in the acquired operation information. The surface temperature acquisition section 15 acquires, for example, the surface temperature estimated by the estimation section 17 in the prescribed period included in the acquired operation information. In addition, the surface temperature acquisition section 15 acquires a measured or externally provided surface temperature instead of the estimated surface temperature. The surface temperature acquisition section 15 acquires, for example, the surface temperature TP_A (°C) (A = 1, 2,... t - 1) every other sampling period t_1.

[0040] The calculation section 16 is realized by, for example, a CPU acting. The calculation section 16 calculates the progression of the ratio of the surface temperature to the set temperature with respect to the progression of the heater output included in the operation information, based on the acquired operation information and the acquired surface temperature. The calculation section 16 calculates, for example, the value of the surface temperature / set temperature for each heater output included in the operation information. In the present embodiment, the calculation section 16 calculates (TP_A / S) (A = 1, 2,... t - 1) every other sampling period t_1.

[0041] The estimation section 17 is realized by, for example, a CPU acting. The estimation section 17 estimates the surface temperature of the heater 102 at a prescribed time, based on the operation information, the performance information, and the acquired surface temperature. Specifically, the estimation section 17 estimates the surface temperature at a prescribed time using a performance included in the performance information that is similar or identical to the progression of the operation information and the calculated progression of the ratio. The estimation section 17 estimates the surface temperature at a prescribed time from the ratio of the set temperature to the surface temperature at a time corresponding to the prescribed time shown by the performance that is similar or identical to the progression. The estimation section 17 determines, for example, a performance in a period that is similar or identical to the progression of the heater output and the progression of the ratio of the set temperature to the surface temperature included in the operation information in a predetermined period immediately before the prescribed time from the performance information. The estimation section 17 acquires the ratio of the set temperature to the surface temperature at the next time (corresponding to the prescribed time) after the similar or identical period included in the determined performance. Then, the estimation section 17 estimates the surface temperature at the prescribed time by multiplying the acquired ratio by the set temperature included in the operation information. Furthermore, the estimation section 17 estimates the surface temperature at a prescribed time using, for example, the performance with the highest degree of agreement (kappa coefficient or the like) of the progression as the performance similar to the progression.

[0042] The output section 18 is, for example, a display device such as a display. The output section 18 outputs the estimated surface temperature to the outside. As shown in FIG. 1, the output section 18 displays, for example, the position of the heater 102 with respect to the cylinder 101, the set temperature, the heater output, and the current surface temperature. Figure 6 The output section 18 is, for example, a display device such as a display. The output section 18 outputs the estimated surface temperature to the outside. As shown in FIG. 1, the output section 18 displays, for example, the position of the heater 102 with respect to the cylinder 101, the set temperature, the heater output, and the current surface temperature.

[0043] The output control section 19 is realized by, for example, a CPU acting. The output control section 19 causes the output section 18 to output the estimated surface temperature.

[0044] Next, the flow of the process performed by the control device 1 will be described with reference to Figure 7

[0045] First, the performance information acquisition section 14 acquires performance information (step S1). The performance information acquisition section 14 acquires, for example, a plurality of pieces of performance information from the performance information storage section 13.

[0046] Next, the action information acquisition section 12 acquires action information (step S2). The action information acquisition section 12 acquires, for example, action information that is stored in advance in the action information storage section 11.

[0047] Next, the surface temperature acquisition section 15 acquires a surface temperature corresponding to the action information (step S3).

[0048] Next, the calculation section 16 calculates a change in the ratio of the surface temperature to the set temperature with respect to a change in the heater output included in the action information, on the basis of the acquired action information and the acquired surface temperature (step S4). Next, the estimation section 17 estimates the surface temperature of the heater 102 from the action information, the surface temperature, and the performance information (step S5).

[0049] In step S6, the output control section 19 outputs the estimated surface temperature to the output section 18. The output section 18 displays, for example, the estimated surface temperature.

[0050] Next, it is determined whether or not the estimation of the surface temperature is repeated (step S7). In the case where the estimation is repeated (step S7: YES), the process returns to step S2. On the other hand, in the case where the estimation is ended (step S7: NO), the process of the present flow is ended.

[0051] Next, the program of the present embodiment will be described.

[0052] Each structure included in the control device 1 of the injection molding machine 10 can be realized by hardware, software, or a combination thereof, respectively. Here, the meaning of being realized by software is that it is realized by a computer reading and executing a program.

[0053] ​The program can be stored and supplied to a computer using various types of non-transitory computer readable media. The non-transitory computer readable media include various types of tangible storage media having physical patterns of tracks. Examples of the non-transitory computer readable media include a magnetic recording medium (e.g., a floppy disk, a tape, a hard disk drive), an opto-magnetic recording medium (e.g., a magneto-optical disk), a CD-ROM (Read Only Memory), a CD-R, a CD-R / W, a semiconductor memory (e.g., a mask ROM, a PROM (Programmable ROM), an EPROM (Erasable PROM), a flash ROM, a RAM (Random Access Memory)). In addition, the program can be supplied to a computer by various types of transitory computer readable media. Examples of the transitory computer readable media include an electrical signal, an optical signal, and an electromagnetic wave. The transitory computer readable media can supply the program to a computer via a wired communication path, such as an electrical wire and an optical fiber, or a wireless communication path.

[0054] According to the control device 1 and the program of the injection molding machine 10 according to one embodiment, the following effects can be obtained.

[0055] (1) The injection molding machine 10 has a cylinder 101 and a heater 102 arranged around the cylinder 101, and the control device 1 of the injection molding machine 10 is configured to estimate the surface temperature of the heater 102 at a prescribed time. The control device 1 of the injection molding machine 10 includes an operation information acquisition section 12 configured to acquire, as operation information, the heater output of the heater 102 and the set temperature of the heater 102 in a prescribed period immediately before the prescribed time, a surface temperature acquisition section 15 configured to acquire, as the surface temperature of the heater 102 in the prescribed period, the surface temperature included in the acquired operation information, an actual performance information acquisition section 14 configured to acquire, as actual performance information, the change in the ratio of the surface temperature to the set temperature of the heater with respect to the change in the heater output of the heater, and an estimation section 17 configured to estimate the surface temperature of the heater at the prescribed time on the basis of the operation information, the actual performance information, and the acquired surface temperature.

[0056] Further, the program causes the computer to function as the control device 1 of the injection molding machine 10 having the cylinder 101 and the heater 102 arranged around the cylinder 101, the program causes the computer to estimate the surface temperature of the heater at the prescribed time, the program causes the computer to function as the operation information acquisition section 12 that acquires the heater output of the heater 102 and the set temperature of the heater 102 in the prescribed period immediately before the prescribed time as operation information, the surface temperature acquisition section 15 that acquires the surface temperature of the heater 102 in the prescribed period included in the acquired operation information, the actual achievement information acquisition section 14 that acquires the actual achievement of the ratio of the surface temperature to the set temperature of the heater 102 with respect to the progress of the heater output of the heater 102 as actual achievement information, and the estimation section 17 that estimates the surface temperature of the heater 102 at the prescribed time based on the operation information, the actual achievement information, and the acquired surface temperature.

[0057] Thus, the accuracy of the estimated surface temperature of the heater 102 can be improved regardless of the shape (unevenness) of the surroundings of the cylinder 101. Further, a physical sensor or the like does not need to be provided on the surface of the heater 102, so the cost can be suppressed. Thus, the heat release amount from the surface of the heater 102 to the air can be calculated with further high accuracy. As a result, the heater is long-lived, and the power of the injection molding machine is saved by setting the operation and molding conditions that minimize the heat release amount.

[0058] (2) The control device 1 of the injection molding machine 10 further has the calculation section 16 that calculates the progress of the ratio of the surface temperature to the set temperature with respect to the progress of the heater output included in the operation information based on the acquired operation information and the acquired surface temperature, and the estimation section 17 estimates the surface temperature at the prescribed time using the actual achievement similar to or identical to the progress of the ratio of the operation information and the calculated ratio included in the actual achievement information. Thus, the surface temperature can be easily estimated by acquiring the heater output and the set temperature.

[0059] (3) The surface temperature acquisition section 15 acquires the surface temperature of the heater 102 in the form of the ratio of the surface temperature to the set temperature of the heater 102, and the estimation section 17 estimates the surface temperature at the prescribed time using the actual achievement similar to or identical to the progress of the ratio of the operation information and the acquired ratio included in the actual achievement information. Thus, the surface temperature can also be easily estimated by directly acquiring the ratio of the set temperature to the surface temperature.

[0060] (4) The estimation unit 17 estimates the surface temperature of the prescribed time from the ratio of the surface temperature of the time corresponding to the prescribed time to the set temperature shown by the performance similar or identical to the push and the set temperature. Thereby, since the surface temperature is estimated based on the past performance, it is possible to improve the precision of the estimated surface temperature.

[0061] The above describes the preferred embodiments of the control device and program of the injection molding machine of the present disclosure, but the present disclosure is not limited to the above-described embodiments, and can be appropriately changed.

[0062] For example, in the above-described embodiments, as shown in Figure 8 The output control unit 19 can also cause the output unit 18 to display the measurement position at the time of the learning performance information of the surface temperature of the heater 102. The performance information storage unit 13 stores the performance information including the measurement position. The estimation unit 17 estimates the surface temperature of the heater 102 for each measurement value included in the performance information. Thereby, it is possible to improve the visibility of the surface temperature of the heater 102.

[0063] In addition, in the above-described embodiments, as shown in Figure 9 The output control unit 19 can also cause the output unit 18 to display the scatter plot obtained by summarizing the surface temperature of the heater 102 for each prescribed time. Thereby, it is possible to display the surface temperature of the heater 102 in time series, so it is possible to easily monitor the abnormality of the surface temperature of the heater 102.

[0064] In addition, in the above-described embodiments, as shown in Figure 10 The output control unit 19 can also cause the output unit 18 to display the surface temperature of the heater 102 in a list for each prescribed time. The output control unit 19 can also cause the output unit 18 to display, for example, the maximum value (temperature), the minimum value (temperature), the average value, the difference between the maximum value and the minimum value, and the standard deviation for each heater 102.

[0065] In addition, in the above-described embodiments, it is assumed that the action information acquisition unit 12 acquires the action information after the performance information acquisition unit 14 acquires the performance information, but it is not limited thereto. It can also be configured such that the action information acquisition unit 12 acquires the action information before the performance information acquisition unit 14 acquires the performance information.

[0066] In addition, in the above-described embodiments, the injection molding machine 10 can be any one of the coaxial reciprocating screw type and the plunger type. In addition, in the above-described embodiments, the surface temperature of the heater 102 included in the performance information can be a temperature measured by a temperature sensor (not shown) as a direct method, or a temperature measured by a thermal imaging (radiation thermometer, not shown) as an indirect method.

[0067] In addition, in the above-described embodiment, the output section 18 can also be configured independently of the control device 1 (injection molding machine 10). In addition, the control device 1 can also manage a plurality of injection molding machines 10.

[0068] In addition, in the above-described embodiment, the estimation section 17 can also be configured to estimate at a prescribed time such as every unit time or every cycle time. In addition, in the above-described embodiment, the estimation section 17 can also be configured to estimate an average value for every fixed time or to estimate the surface temperature at a specific time.

[0069] In addition, in the above-described embodiment, the operation information acquisition section 12 can also use a detected temperature (or an estimated surface temperature) detected at the temperature control point in place of the set temperature. In addition, in the above-described embodiment, the estimation section 17 can also estimate the surface temperature of the heater 102 at the start of the operation of the injection molding machine 10 as E% (E is an arbitrary constant or variable) of the detected temperature of the control point of the heater 102. The estimation section 17 can also estimate the surface temperature as a variable E such as E = 95 when the detected temperature is below 50°C and E = 90 when the detected temperature is 50°C or higher, for example.

[0070] In addition, in the above-described embodiment, the prescribed time is not limited to the current time and can also be a past or future time. When the prescribed time is in the past, the operation information acquisition section 12 acquires the heater output and the set information for a prescribed period immediately before the prescribed time. In addition, when the prescribed time is in the future, the operation information acquisition section 12 acquires the assumed heater output and the set information for a prescribed period immediately before the prescribed time.

[0071] In addition, in the above-described embodiment, the surface temperature acquisition section 15 can also acquire a ratio of the set temperature to the surface temperature in place of the surface temperature. In this case, the control device 1 can also not have the calculation section 16.

[0072] Explanation of Reference Numerals

[0073] 1: control device; 10: injection molding machine; 12: operation information acquisition section; 14: performance information acquisition section; 15: surface temperature acquisition section; 16: calculation section; 17: estimation section; 101: cylinder; 102: heater; 103: safety cover.

Claims

1. A control device of an injection molding machine that has a cylinder and a heater disposed around the cylinder, the control device of the injection molding machine being configured to estimate a surface temperature of the heater at a prescribed time, the control device of the injection molding machine comprising: an action information acquisition section configured to acquire a heater output of the heater and a set temperature of the heater in a prescribed period immediately before the prescribed time as action information; a surface temperature acquisition section configured to acquire a surface temperature of the heater in the prescribed period included in the acquired action information; an actual performance information acquisition section configured to acquire an actual performance of a change in a ratio of the surface temperature to the set temperature of the heater with respect to a change in the heater output of the heater as actual performance information; an estimation section configured to estimate the surface temperature of the heater at the prescribed time based on the action information, the actual performance information, and the acquired surface temperature; and a calculation section configured to calculate a change in the ratio of the surface temperature to the set temperature with respect to a change in the heater output included in the action information based on the acquired action information and the acquired surface temperature, the estimation section estimating the surface temperature at the prescribed time using an actual performance included in the actual performance information that has the highest degree of coincidence with the change in the action information and the calculated ratio.

2. The control device of the injection molding machine according to claim 1, wherein the surface temperature acquisition section acquires the surface temperature of the heater in the form of a ratio of the surface temperature to the set temperature of the heater, the estimation section estimating the surface temperature at the prescribed time using an actual performance included in the actual performance information that has the highest degree of coincidence with the change in the action information and the acquired ratio.

3. The control device of the injection molding machine according to claim 1 or 2, wherein the estimation section estimates the surface temperature at the prescribed time from a ratio of the surface temperature to the set temperature of the heater at a time corresponding to the prescribed time indicated by the actual performance that has the highest degree of coincidence with the change.

4. A computer-readable medium that is a non-transitory computer-readable medium that stores a program that causes a computer to function as a control device of an injection molding machine that has a cylinder and a heater disposed around the cylinder, the control device of the injection molding machine being configured to estimate a surface temperature of the heater at a prescribed time, the program causing the computer to function as: an action information acquisition section configured to acquire a heater output of the heater and a set temperature of the heater in a prescribed period immediately before the prescribed time as action information; a surface temperature acquisition section configured to acquire a surface temperature of the heater in the prescribed period included in the acquired action information; an actual performance information acquisition section configured to acquire an actual performance of a change in a ratio of the surface temperature to the set temperature of the heater with respect to a change in the heater output of the heater as actual performance information; ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ an estimating section that estimates the surface temperature of the heater at the prescribed time based on the operation information, the performance information, and the acquired surface temperature; and a calculating section that calculates the change in the ratio of the surface temperature to the set temperature with respect to the change in the heater output included in the operation information based on the acquired operation information and the acquired surface temperature, the estimating section estimates the surface temperature at the prescribed time using the performance included in the performance information that has the highest degree of correspondence with the change in the calculated ratio.

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