Molding machine system, torque derivation system, torque derivation method, and program

Abstract

To alleviate dimensional restrictions for mounting torque detection devices on molding machines.SOLUTION: A molding machine system 100 comprises: a molding machine 1 having a cylinder 2, a first screw 31 and a second screw 32 incorporated in the cylinder 2, and a motor 4a for rotary-driving the first screw 31 and the second screw 32; a torque detection apparatus (10 and 83) for detecting a torque of the motor 4a as an example of feature quantity related to an operation condition of the molding machine 1; a torque detection device 11 mounted on a rotary shaft 71 of the first screw 31 to detect a torque of the first screw 31; and a torque derivation apparatus 85 for deriving a torque of the second screw 32 on the basis of the torque of the motor detected by the torque detection apparatus (10 and 83) and the torque of the first screw 31 detected by the torque detection device 11.SELECTED DRAWING: Figure 7

Description

Technical Field

[0006] , , , , ,

[0007] ,

[0001] The present invention relates to a molding machine system, a torque derivation system, a torque derivation method, and a program therefor.

Background Art

[0002] A molding machine kneads, transports, and melts raw materials introduced into a cylinder by rotating a screw in the cylinder.

[0003] In a molding machine, the screw may be damaged due to some abnormality during use. When the screw is damaged, replacement of the screw and interruption of product production are inevitable. Therefore, it is important to grasp the state of the screw, particularly the torque generated in the screw, during use of the molding machine.

[0004] Based on the above-described background, a technique for detecting the torque generated in a screw by attaching a torque detection device to the axis of the screw is described in Patent Document 1.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Among molding machines, there is a type having a plurality of screws. When applying the technique of Patent Document 1 to this type of molding machine, a device is attached to the axis of each screw.

[0007] However, when a device is attached to each screw, the volume occupied by the device increases, and dimensional constraints occur in the attachment of the device.

Means for Solving the Problems

[0008] A molding machine system according to one embodiment comprises a molding machine, a feature identification device, a torque detection device, and a torque derivation device. The molding machine is configured to rotate a first screw and a second screw, which are built into a cylinder, using a motor. The feature identification device identifies feature quantities related to the operating state of the molding machine, such as the torque of the motor. The torque detection device is mounted on the rotation axis of the first screw. The torque derivation device derives the torque of the second screw based on the identified feature quantities and the detected torque of the first screw. [Effects of the Invention]

[0009] According to one embodiment, the dimensional constraints on mounting a torque detection device can be relaxed in a molding machine having multiple screws. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows the hardware configuration of the molding machine system according to Embodiment 1. [Figure 2] This is a side view of the molding machine. [Figure 3] This is a top view of the molding machine. [Figure 4] This is a partially enlarged top view of the molding machine. [Figure 5] This is a partially enlarged cross-sectional view of a molding machine. [Figure 6] This diagram shows the hardware configuration of the control and monitoring device. [Figure 7] This diagram shows the functional block configuration of the control and monitoring device. [Figure 8] This is a diagram that simulates a function table. [Figure 9] This flowchart shows the operation of the molding machine system. [Modes for carrying out the invention]

[0011] An embodiment will be described. Each of the embodiments described below is an example for realizing the invention and does not limit the technical scope of the invention.

[0012] In addition, in each of the following embodiments, components having the same function are denoted by the same reference numerals, and repeated descriptions are omitted unless particularly necessary.

[0013] (Embodiment 1) A molding machine system according to Embodiment 1 will be described. Note that the molding machine according to the present embodiment is a molding machine having two screws, and a two-screw extruder for resin molding is assumed. As other examples of the molding machine, for example, an injection molding machine, a granulator, a film manufacturing machine, a blow molding machine, etc. can be considered.

[0014] <Overview of the Molding Machine System> The molding machine system according to Embodiment has a molding machine including a cylinder, two screws built in the cylinder, and a motor for rotationally driving the two screws. Further, the molding machine system includes a feature quantity specifying device for specifying a feature quantity related to the operating state of the molding machine, and a torque detecting device attached to the rotation shaft of one of the screws for detecting the torque of the one screw. The molding machine system further includes a torque deriving device for deriving the torque of the other screw based on the feature quantity specified by the feature quantity specifying device and the torque of the one screw detected by the torque detecting device.

[0015] <Configuration of the Molding Machine System> The hardware configuration of the molding machine system according to Embodiment will be described.

[0016] FIG. 1 is a diagram showing the hardware configuration of the molding machine system according to Embodiment 1. As shown in FIG. 1, the molding machine system 100 includes a molding machine 1 and a control and monitoring system 90. The molding machine 1 and the control and monitoring system 90 are connected so that communication of control signals and data is possible. The connection may be wired or wireless.

[0017] The configuration of the molding machine 1 will be described. As shown in FIG. 1, the molding machine 1 is disposed on a support base 6. The molding machine 1 includes a cylinder 2, a screw 3, a rotation drive mechanism 4, a die (mold) 5, and a temperature adjustment unit 13.

[0018] The cylinder 2 is configured such that the screw 3 is built therein. An opening is formed on the upper surface of the cylinder 2 to allow the introduction of raw materials into the cylinder 2. A temperature adjustment unit 13 for adjusting the temperature of the cylinder 2 is installed on the outer surface of the cylinder 2.

[0019] The screw 3 is arranged and supported in the cylinder 2 so as to be rotatable about a rotation axis parallel to the longitudinal direction of the screw 3. By rotating in the cylinder 2, the screw 3 kneads, transports, and melts the raw materials introduced into the cylinder 2. A rotation drive mechanism 4 is connected to the screw 3.

[0020] The rotation drive mechanism 4 includes a motor 4a and a transmission 4b. The transmission 4b is connected to the motor 4a. The transmission 4b is interposed between the motor 4a and the screw 3. The transmission 4b has a function of changing the rotation speed of the motor 4a to a rotation speed suitable for the screw 3. The joint 8 is a member that connects the output shaft 7 of the transmission 4b and the screw 3. The motor 4a and the transmission 4b are connected by a motor output shaft 9, and the tip of the output shaft 7 of the transmission 4b and the rear end of the screw 3 are connected by the joint 8.

[0021] The rotational motion of the motor 4a is transmitted to the screw 3 via the motor output shaft 9 of the motor 4a, the transmission 4b, and the output shaft 7 of the transmission 4b, causing the screw 3 to rotate. That is, when the rotational motion of the motor 4a is transmitted to the transmission 4b, the output shaft 7 of the transmission 4b rotates at the same or different rotational speed as the rotational speed of the motor 4a, and the screw 3 connected to the output shaft 7 rotates at the same rotational speed as the output shaft 7.

[0022] The die 5 is mounted at the tip of the cylinder 2, that is, at the end in the direction from the rotary drive mechanism 4 toward the screw 3. The die 5 functions to shape and extrude the molten resin being pushed out from the cylinder 2 into a predetermined cross-sectional shape. In this embodiment, the die 5 is a mold for extrusion molding.

[0023] The temperature control unit 13 is located on the outer surface of the cylinder 2. The temperature control unit 13 has the function of adjusting the temperature of the cylinder 2. The temperature control unit 13 includes, for example, a heater.

[0024] The molding machine 1 is equipped with a motor torque meter (an example of a feature identification device) 10, a telemeter (an example of a torque detection device) 11, and a base unit 12 as components of the control and monitoring system 90. Details of the motor torque meter 10, telemeter 11, and base unit 12 will be described later.

[0025] Figure 2 is a side view of the molding machine, and Figure 3 is a top view of the molding machine. As shown in Figures 2 and 3, the screw 3 includes a screw (an example of a first screw) 31 and a screw (an example of a second screw) 32. The output shaft 7 of the transmission 4b includes an output shaft 71 and an output shaft 72. Here, screw 31 will be referred to as the left screw, and screw 32 as the right screw. Similarly, output shaft 71 will be referred to as the left output shaft, and output shaft 72 as the right output shaft. The left screw 31 and the right screw 32 are arranged to mesh with each other within the cylinder 2. The left screw 31 rotates around its axis of rotation, and the right screw 32 rotates around its axis of rotation.

[0026] The left screw 31 and the right screw 32 are housed within the cylinder 2, but portions of the left screw 31 and the right screw 32 protrude from the upstream end of the cylinder 2. The portion of the left screw 31 protruding from the cylinder 2 is connected to the left output shaft 71 of the transmission 4b via a coupling 8. Similarly, the portion of the right screw 32 protruding from the cylinder 2 is connected to the right output shaft 72 of the transmission 4b via a coupling 8. Note that the portion of the left screw 31 protruding from the cylinder 2, the coupling 8, and the left output shaft 71 of the transmission 4b are examples of the rotation shafts of the first screw in this invention.

[0027] <Configuration of the control and monitoring system> Next, the configuration of the control monitoring system 90 will be described. As shown in Figure 1, the control monitoring system 90 includes a motor torque meter 10, a telemeter 11, a base unit 12, and a control monitoring device 80.

[0028] The motor torque meter 10 is connected to the motor 4a and measures the motor torque (an example of motor torque) MT, which is the torque generated at the motor output shaft 9 of the motor 4a. Specifically, a sensor for detecting strain is attached to the motor output shaft 9 of the motor 4a. The strain of the motor output shaft 9 is detected by this sensor, and the motor torque MT is measured based on the degree of strain. The motor torque meter 10 continuously measures the motor torque MT at predetermined time intervals, for example, intervals of about 0.1 milliseconds to 10 milliseconds. In this embodiment, the motor torque meter 10 measures the motor torque MT at 1-millisecond intervals. The motor torque meter 10 is connected to the control monitoring device 80. The motor torque meter 10 sequentially outputs the measured motor torque MT data to the control monitoring device 80.

[0029] Figure 4 is a partially enlarged top view of the molding machine. Figure 4 shows a top view of section 1a, which includes the area from the transmission 4b to the cylinder 2. Figure 5 is a partially enlarged cross-sectional view of the molding machine. Figure 5 shows a cross-sectional view at the position of line AA in Figure 4.

[0030] As shown in Figure 4, the telemeter 11 is attached to the left output shaft 71 of the transmission 4b. The left output shaft 71 is connected to the left screw 31 by a coupling 8, and the telemeter 11 detects or senses conditions related to fluctuations or deformations of the left screw 31.

[0031] As the telemeter 11, for example, the telemeter disclosed in the patent document International Publication No. 2021 / 074964 can be used. The telemeter 11 has, for example, a sensor that outputs a signal corresponding to the degree of deformation or strain of an object. The sensor includes, for example, an element whose electrical resistance changes due to the deformation or strain of the object.

[0032] When the left screw 31 rotates and torque is applied to it, the left screw 31 itself deforms slightly. Along with the deformation of the screw, the element also deforms, and the electrical resistance of the element changes. By reading the electrical resistance of this element, the degree of deformation and its change over time can be determined. Using this principle, the condition of the screw can be detected by determining the direction and extent of deformation.

[0033] The telemeter 11 can detect torsional strain, bending strain, thermal strain, torque, bending, degree of deformation, deformation mode, vibration, degree of vibration, vibration mode, or fatigue due to the accumulation of these, degree of fatigue, etc., as conditions of the left screw 31.

[0034] In this embodiment, the telemeter 11 detects at least the left screw torque (an example of the torque of the first screw) T1 occurring in the left screw 31. The telemeter 11 continuously detects the left screw torque T1 at predetermined time intervals, for example, intervals of about 0.1 milliseconds to 10 milliseconds. In this embodiment, the telemeter 11 detects the left screw torque T1 at 1-millisecond intervals.

[0035] The mounting position of the telemeter 11 is not limited to the above position. For example, the telemeter 11 may be mounted on the part of the left screw 31 that protrudes from the cylinder 2, or on the joint 8 that connects the left output shaft 71 and the left screw 31. Alternatively, the telemeter 11 may be built into the joint 8.

[0036] As shown in Figure 5, the base portion 12 is positioned on the support base 6. The base portion 12 is positioned opposite the telemeter 11 attached to the left screw 31, with a predetermined spatial gap between them. The telemeter 11 rotates together with the left screw 31 when the left screw 31 and the right screw 32 rotate.

[0037] The base unit 12 can supply power to the telemeter 11 via wireless power transmission using a coil. Wireless communication devices are also built into both the telemeter 11 and the base unit 12. The base unit 12 is wirelessly connected to the telemeter 11, enabling them to send and receive data. The base unit 12 sequentially receives the left-side screw torque T1 detected by the telemeter 11. As shown in Figure 1 or Figure 4, the base unit 12 is connected to the control monitoring device 80. The base unit 12 sequentially outputs the data of the left-side screw torque T1 detected by the telemeter 11 to the control monitoring device 80.

[0038] <Hardware configuration of the control and monitoring device> Figure 6 shows the hardware configuration of the control and monitoring device.

[0039] As shown in Figure 6, the control and monitoring device 80 includes a storage 80a, a memory 80b, a processor 80c, a display 80d, an operation unit 80e, and an interface 80f. The storage 80a to the interface 80f are connected to a bus 80g, which is a data transmission path, and can send and receive signals or data from each other. The control and monitoring device 80 is composed of, for example, a computer, or a computer and peripheral devices connected to the computer.

[0040] Storage 80a stores various programs and data. These programs include, for example, operating systems, device drivers, and control / monitoring programs. The data includes, for example, data used when executing control / monitoring programs. Storage 80a is comprised of, for example, SSDs (Solid State Drives), HDDs (Hard Disk Drives), eMMCs (embedded Multi Media Cards), UFS (Universal Flash Storage), SD (Secure Digital) cards, USB (Universal Serial Bus) flash drives, and optical discs.

[0041] Memory 80b temporarily stores data processed by processor 80c. Memory 80b is composed of semiconductor memory, such as RAM (Random Access Memory).

[0042] The processor 80c performs various arithmetic and data processing. By executing programs stored in the storage 80a using memory 80b, it functions as various functional blocks. The processor 80c is composed of components such as an MPU (Micro-Processing Unit) and a CPU (Central Processing Unit).

[0043] The display 80d displays images or text information on its screen. The display 80d is composed of, for example, a liquid crystal display, an organic electro-luminescence (OLED) display, or a touch panel display.

[0044] The control unit 80e accepts various operations from the user. The control unit 80e is composed of, for example, a keyboard, mouse, touch panel, etc.

[0045] Interface 80f is connected to external devices and performs data transmission and reception. In this embodiment, interface 80f is connected to the base unit 12 and the motor torque meter 10. Interface 80f receives data corresponding to the left screw torque T1 detected by the telemeter 11, which is acquired by the base unit 12. Interface 80f also receives data corresponding to the motor torque MT measured by the motor torque meter 10. Interface 80f stores the received data in memory 80b or in storage 80a.

[0046] <Functional block configuration of the control and monitoring device> Figure 7 shows the functional block configuration of the control and monitoring device.

[0047] As shown in Figure 7, the control monitoring device 80 includes an operating condition setting unit 81, an operating control unit 82, a motor torque acquisition unit (an example of a feature quantity identification device) 83, a left screw torque acquisition unit (an example of a first screw torque acquisition device) 84, a right screw torque derivation unit (a torque derivation device, an example of a second screw torque derivation device) 85, a torque display unit (an example of a display unit) 86, and an alert notification unit (an example of a notification unit) 87. Each part constituting the control monitoring device 80 is realized by the processor 80c executing a control monitoring program stored in the storage 80a.

[0048] The operating condition setting unit 81 sets the operating conditions of the molding machine 1 based on user input. Possible operating conditions include, for example, the raw materials introduced into the molding machine 1 (main material, main additives, etc.), the mixing ratio of the materials constituting the raw materials, cylinder diameter, cylinder length, cylinder temperature, screw rotation speed, processing amount per unit time, transmission gear ratio, screw configuration, etc.

[0049] The operation control unit 82 controls the motor 4a, the transmission 4b, and the temperature control unit 13 based on the set operating conditions. The operation control unit 82 also controls the on / off operation of the motor 4a in response to user operations. For example, the operation control unit 82 sets the current supplied to the motor 4a or the gear ratio of the transmission 4b so that the rotational speed of the output shaft 7 of the transmission 4b becomes the set screw rotational speed. For example, it controls the temperature control unit 13 so that the temperature of the cylinder 2 becomes the set cylinder temperature. The operation control unit 82 may also control the motor 4a to turn off the rotational drive in response to the reception of an alert signal, which will be described later.

[0050] The motor torque acquisition unit 83 acquires the motor torque MT, which is the torque generated at the motor output shaft 9 of the motor 4a. In this embodiment, the torque measured by the motor torque meter 10 provided on the motor output shaft 9 of the motor 4a is acquired as the motor torque MT. The motor torque meter 10 measures the motor torque MT as described above, for example at 1-millisecond intervals, and sequentially outputs a signal representing the measurement result. The motor torque acquisition unit 83 sequentially receives the signal output from the motor torque meter 10 and acquires the motor torque MT of the motor 4a, which is the measured value.

[0051] The motor torque acquisition unit 83 may acquire the estimated torque MT based on the motor current supplied to the motor 4a. It is generally known that the torque of a motor is approximately proportional to the motor current supplied to the motor. Therefore, the motor torque MT can be estimated by multiplying the motor current by a predetermined coefficient. When estimating the motor torque from the motor current, it is not necessary to attach the motor torque meter 10 to the motor 4a, thus enabling space saving, and reducing installation and maintenance costs.

[0052] The left screw torque acquisition unit 84 is connected to the base unit 12. The left screw torque acquisition unit 84 acquires the left screw torque T1 generated in the left screw 31 detected by the telemeter 11 via the base unit 12. As described above, the telemeter 11 measures the left screw torque T1 at intervals of, for example, 1 millisecond and sequentially outputs a signal representing the measurement result. The base unit 12 sequentially acquires the left screw torque T1 output from the telemeter 11 and outputs it to the left screw torque acquisition unit 84. The left screw torque acquisition unit 84 sequentially acquires the left screw torque T1 output from the base unit 12.

[0053] The right-side screw torque derivation unit 85 derives the right-side screw torque (an example of the torque of the second screw) T2, which is the torque generated in the right-side screw 32, based on the acquired motor torque MT, the left-side screw torque T1, and a function determined according to the set operating conditions. The derivation of the right-side screw torque T2 is performed each time the motor torque MT and the left-side screw torque T1 are acquired. The right-side screw torque derivation unit 85 stores the function used to derive the right-side screw torque T2. The function is stored as a table obtained by associating the operating conditions of the molding machine 1 with the function that should be used when the molding machine 1 is operated under those operating conditions. The function is determined in advance for each operating condition based on the results of actual tests, simulations, etc. Details of the method for deriving the right-side screw torque T2 will be described later.

[0054] The torque display unit 86 has the function of displaying the motor torque MT, the left screw torque T1, and the right screw torque T2 in near real time. The torque display unit 86 also has the function of displaying a graph showing the time change of the left screw torque T1 and the right screw torque T2 on the same time axis. The torque display unit 86 can independently control each of the above functions on or off in response to user operation. When each of the above functions is on, the torque display unit 86 displays each torque value or graph at predetermined time intervals.

[0055] In this embodiment, the torque display unit 86 displays each torque value or a graph representing the time change of torque on the display 80d of the control monitoring device 80. As another example, each torque value or graph information may be transmitted to a monitoring system located in a separate room from the manufacturing room where the molding machine 1 is installed, and displayed on the display of the monitoring system. Alternatively, each torque value or graph information may be transmitted via a server to a management system installed in a remote control center, and displayed on the display of the management system.

[0056] The alert notification unit 87 outputs an alert if at least one of the motor torque MT, left screw torque T1, and right screw torque T2 meets a predetermined condition, for example, a condition deemed abnormal. When outputting an alert, the alert notification unit 87 may also output an alert signal to the operation control unit 82 to turn off the drive of the motor 4a.

[0057] The alert notification unit 87 outputs an alert, for example, when the average or peak value of the motor torque MT per unit time exceeds the threshold THm. The alert notification unit 87 also outputs an alert, for example, when the average or peak value of the left screw torque T1 per unit time exceeds the threshold TH1. The alert notification unit 87 also outputs an alert, for example, when the average or peak value of the right screw torque T2 per unit time exceeds the threshold TH2.

[0058] When the alert notification unit 87 outputs an alert, it displays the alert information on the display 80d of the control monitoring device 80. If the control monitoring device 80 is equipped with a speaker, it may also output an alert sound to the speaker. As another example, an alert signal may be sent to a monitoring system located in a separate room from the manufacturing room where the molding machine 1 is installed, causing the alert to be displayed on the monitoring system's display or speaker. Alternatively, an alert signal may be sent to a management system installed in a remote control center, causing the alert to be displayed on the management system's display or speaker.

[0059] <Method for deriving the right-side screw torque> Here, we will detail the method for deriving the right-side screw torque T2.

[0060] Based on measurement results from an actual molding machine 1, the applicant found a correlation between motor torque MT, left screw torque T1, and right screw torque T2. The found correlation is expressed by the following formula 1.

[0061] T2 = f(MT, T1) …(Equation 1) Here, f(MT,T1) is a function that takes motor torque MT and left screw torque T1 as input parameters and outputs right screw torque T2. The function f may be a linear function or a nonlinear function; that is, it may be a first-order function or a second-order or higher function.

[0062] As a simple example of a function f, it can be expressed as, for example, equation 2 below.

[0063] T2 = f(MT, T1) = MT × k - T1 + t …(Equation 2) Here, k is a coefficient multiplied by the motor torque MT, and t is a constant added to the term that includes the left screw torque T1.

[0064] It is known that the function f suitable for calculating the right-side screw torque T2 is not always the same, but differs depending on the configuration of the molding machine 1 and the operating conditions, including the raw materials introduced. Therefore, in practice, the function f to be used for each operating condition is determined based on the results of various actual machine measurements with different operating conditions.

[0065] For example, after determining the function f to be used for each operating condition, a table (hereinafter referred to as the function table) is created in advance by associating the operating condition with the function f to be used when the molding machine 1 is operated under that operating condition. The created function table is then stored in the right-side screw torque derivation unit 85.

[0066] Figure 8 is a diagram illustrating a function table. As shown in Figure 8, a function table is created by associating each operating condition with the function f that should be used when the molding machine 1 is operated under that operating condition. In the function table shown in Figure 8, for example, operating condition C1 is associated with function f1, and operating condition C2 is associated with function f2. In other words, when operating condition C1 is set, function f1 is used as the torque derivation function, and when operating condition C2 is set, function f2 is used as the torque derivation function.

[0067] When the operating conditions are set by the operating condition setting unit 81, the right-side screw torque derivation unit 85 reads a function f corresponding to the set operating conditions by referring to the function table. The read-out function f is determined as the torque derivation function. Then, the acquired left-side screw torque T1 and motor torque MT are input as parameters to the determined torque derivation function, and the right-side screw torque T2 is output and derived.

[0068] The operating conditions consist of numerous items. While it is possible to determine a function f for each combination of items that constitute the operating conditions, this would require a considerable amount of time to determine the function f for each operating condition, i.e., to create a function table.

[0069] Therefore, in practice, it is best to identify the items that make up the operating conditions and contribute relatively significantly to the determination (composition) of function f, and then find a suitable function f for each combination of the identified items. This is just one example, but for instance, one could find a suitable function f for each combination of "cylinder diameter," "cylinder length," and "screw rotation speed."

[0070] The torque derivation function may also be determined by calculating the coefficients or constants that make up the function using a formula based on the elements that constitute the operating conditions.

[0071] <Operation flow of the molding machine system> The operation of the molding machine system 100 will be described.

[0072] Figure 9 is a flowchart showing the operation of the molding machine system. As shown in Figure 9, in step S1, the process of setting the operating conditions is executed. Specifically, the operating condition setting unit 81 executes the process of setting the operating conditions of the molding machine 1 in response to user operations. As mentioned above, the operating conditions include items such as the raw materials introduced into the molding machine 1 (main material, main additives, etc.), the mixing ratio of the materials constituting the raw materials, cylinder diameter, cylinder length, cylinder temperature, screw rotation speed, processing amount per unit time, transmission gear ratio, and screw configuration.

[0073] In step S2, the function reading process is executed. Specifically, the right-side screw torque derivation unit 85 reads and determines the function to be used to derive the right-side screw torque T2 based on the set operating conditions. Here, it refers to the function table to read the function corresponding to the set operating conditions and determines the read function as the torque derivation function.

[0074] In step S3, a process is executed to determine whether or not a command to prepare for operation has been issued. Specifically, the operation control unit 82 executes a process to determine whether or not a command to prepare for operation has been entered by the user. If it is determined that a command to prepare for operation has been entered (S3:Yes), the process proceeds to step S4. If it is determined that a command to prepare for operation has not been entered (S3:No), the process returns to step S3.

[0075] In step S4, preparation processing for operation is performed. Specifically, the operation control unit 82 performs various processes to prepare the molding machine 1 for operation. For example, it sets the gear ratio of the transmission 4b so that the screw 3 rotates at the set screw rotation speed. Also, for example, it starts controlling the temperature control unit 13 so that the cylinder 2 reaches the set temperature.

[0076] In step S5, a process is executed to determine whether or not a command to start operation has been issued. Specifically, the operation control unit 82 performs a process to determine whether or not a command to start operation has been entered by the user. If it is determined that a command to start operation has been entered (S5:Yes), the process proceeds to step S6. If it is determined that a command to start operation has not been entered (S5:No), the process returns to step S5.

[0077] In step S6, the operation process is executed. Specifically, the operation control unit 82 performs various processes for operating the molding machine 1. For example, it starts supplying current to the motor 4a and drives the motor 4a.

[0078] In step S7, the motor torque and left screw torque acquisition process is performed. Specifically, the motor torque acquisition unit 83 performs the process of sequentially acquiring the motor torque MT measured by the motor torque meter 10. In addition, the left screw torque acquisition unit 84 performs the process of sequentially acquiring the left screw torque T1 detected by the telemeter 11.

[0079] In step S8, the right-side screw torque derivation process is performed. Specifically, the right-side screw torque derivation unit 85 takes the motor torque MT and the left-side screw torque T1 as inputs to the torque derivation function determined in step S2 and performs a process to sequentially calculate the right-side screw torque T2.

[0080] In step S9, torque display processing is performed. Specifically, the torque display unit 86 performs processing to sequentially update and display the left screw torque T1 or a numerical value based on the left screw torque T1 and the right screw torque T2 or a numerical value based on the right screw torque T2 on the screen of the display 80d. The torque display unit 86 also performs processing to update and display a graph on the same screen at regular time intervals, showing the time change of the left screw torque T1 or a numerical value based on the left screw torque T1 and the right screw torque T2 or a numerical value based on the right screw torque T2 on the same time axis. The torque display unit 86 may further perform processing to display the motor torque MT or a numerical value based on the motor torque MT, or the time change of the motor torque MT or a numerical value based on the motor torque MT.

[0081] In step S10, a torque threshold determination process is performed. Specifically, the alert notification unit 87 performs a process to determine whether the average value of the motor torque MT, left screw torque T1, and right screw torque T2 over a certain period of time exceeds the threshold set for each. If it is determined that any of the torques exceeds the threshold (S10: Yes), the process proceeds to step S11. If it is determined that none of the torques exceed the threshold (S10: No), the process proceeds to step S12.

[0082] In step S11, the alert output process is executed. Specifically, the alert notification unit 87 executes the process of displaying alert information on the screen of the display 80d. At this point, the alert notification unit 87 also executes the process of outputting an alert signal to the operation control unit 82.

[0083] In step S12, a process for determining whether to stop operation is executed. Specifically, the operation control unit 82 performs a process to determine whether or not to stop operation. For example, it determines whether a command to stop operation has been input by the user or whether an alert signal has been received. If a command to stop operation has been input or an alert signal has been received, it is determined that operation should be stopped. If it is determined that operation should be stopped (S12:Yes), the process proceeds to step S13. If it is determined that operation should not be stopped (S12:No), the process returns to step S7 and operation continues.

[0084] In step S13, the operation stop process is executed. Specifically, the operation control unit 82 performs various processes to stop the operation. For example, the operation control unit 82 stops supplying current to the motor 4a. Also, for example, if the operation control unit 82 receives an alert signal, it also stops supplying current to the temperature control unit 13.

[0085] The order of the processes in each of the above steps may be changed as long as it does not interfere with the operation and monitoring of the molding machine 1.

[0086] According to Embodiment 1 with the above configuration, it is not necessary to attach a torque detection device to all screws. Therefore, the dimensional constraints on attaching torque detection devices can be relaxed in a molding machine having multiple screws. For example, even if the distance between the axes of two screws is short and it is difficult to attach a torque detection device to each screw, the device only needs to be attached to one of the screws, thus relaxing the dimensional constraints on device attachment. In addition, the torque detection device and its maintenance costs can be reduced.

[0087] Furthermore, in Embodiment 1, the torque generated in all screws can be understood and appropriately managed and monitored without having to attach torque detection devices to all screws. For example, in a molding machine, screw wear or damage may occur due to some abnormality during use. If these are minor, operation can continue, but the risk of abnormal quality in molded products may increase. If the degree of abnormality increases, screw replacement may be necessary, forcing a disruption of product manufacturing. Therefore, by understanding the condition of the screws, especially the torque generated in the screws, during the use of the molding machine, the condition of the molding machine or molded products can be appropriately managed.

[0088] Furthermore, in Embodiment 1, since the torque display unit 86 described above is provided, the user can visually check the torque generated on the motor or screw shaft and intuitively understand whether there is any abnormality.

[0089] Furthermore, in Embodiment 1, since the alert notification unit 87 described above is provided, an alert is issued when an abnormality is detected in the torque of the motor or screw. Therefore, the user can be notified of the torque abnormality early and take immediate action to minimize the extent of damage or crisis. In addition, it is possible to automatically stop the operation of the molding machine when an abnormality is detected in the torque of the motor or screw. Therefore, even if the user is not near the molding machine, the extent of damage or crisis can be minimized.

[0090] (Embodiment 2) In Embodiment 1, the right-side screw torque T2 is derived using a function, but in Embodiment 2, the right-side screw torque T2 is determined using a model created by machine learning.

[0091] The right-side screw torque derivation unit 85 uses a model created using a generative system model through machine learning to determine the right-side screw torque T2. Specifically, a model is created using machine learning that takes the operating conditions, motor torque MT, and left-side screw torque T1 as inputs and outputs the right-side screw torque T2. In machine learning, data such as operating conditions and torque obtained from actual machine measurements with various operating conditions are used as training data. Then, by inputting the set operating conditions, the measured motor torque MT, and the acquired left-side screw torque T1 into the created model, the right-side screw torque T2 is obtained as the output.

[0092] Even in the above-described embodiment 2, the right-side screw torque T2 can be derived, and the same effects as in embodiment 1 can be obtained.

[0093] (Embodiment 3) In Embodiment 1, the molding machine 1 is assumed to be a twin-screw extruder in which two screws are housed in a cylinder. In Embodiment 3, the molding machine 1 is assumed to be a multi-screw extruder in which three or more screws are housed in a cylinder.

[0094] In this embodiment, torque detection devices are attached to (N-1) of the N screws. Then, based on the torques generated on the (N-1) detected screws and the motor torque MT, the torques generated on the screws that do not have torque detection devices attached are derived. For the derivation, a function obtained from actual machine measurement or a model created by machine learning can be used.

[0095] Even in the above-described embodiment 3, it is not necessary to attach torque detection devices to all screws, thus easing the dimensional constraints on the mounting locations of torque detection devices in the molding machine. Furthermore, the torque detection devices and their maintenance costs can be reduced.

[0096] In the embodiments described above, motor torque is specified as a feature quantity related to the motion state of the molding machine, but the feature quantity is not limited to this. For example, the feature quantity may be the extrusion amount, the rotation speed of the motor or screw, etc. Alternatively, the motor torque may be estimated based on the extrusion amount, the rotation speed of the motor or screw, etc.

[0097] Furthermore, in each of the above embodiments, the method for deriving the right-side screw torque involves determining the motor torque based on operating information, and then determining the right-side screw torque based on the motor torque and the left-side screw torque obtained by the device. However, as an alternative derivation method, a method of directly estimating the right-side screw torque based on the operating information and the left-side screw torque obtained by the device is also conceivable.

[0098] (Embodiment 4) A program to be executed by a computer, which derives the torque of the screws constituting a molding machine, or a computer-readable recording medium on which such a program is recorded, is also an example of an embodiment.

[0099] The above program causes the computer to perform the following steps: a feature acquisition step, a left screw torque acquisition step, and a right screw torque derivation step. The molding machine has a cylinder, a left screw and a right screw built into the cylinder, and a motor that rotates the left screw and the right screw. The feature acquisition step is a step of acquiring feature quantities identified by a feature identification device that identifies feature quantities related to the operating state of the molding machine. The left screw torque acquisition step is a step of acquiring the torque of the left screw detected by a torque detection device attached to the rotation axis of the left screw. The right screw torque derivation step is a step of deriving the torque of the right screw based on the acquired feature quantities and the torque of the left screw.

[0100] Here, the left-side screw torque derivation step may also be a step in which the torque of the right-side screw is derived using a torque derivation function that outputs the torque of the right-side screw when the feature quantity and the torque of the right-side screw are input.

[0101] Furthermore, the right-side screw torque derivation step may also be a step in which the torque derivation function is determined according to the operating conditions of the molding machine.

[0102] Furthermore, the right-side screw torque derivation step may also involve referring to a table that associates operating conditions with the functions to be used when the molding machine is operated under those operating conditions, identifying a function corresponding to the set operating conditions, and determining the identified function as the torque derivation function.

[0103] Furthermore, the table may be a table that associates combinations of multiple items, such as the raw materials introduced into the molding machine, the mixing ratio of the materials constituting the raw materials, the diameter of the cylinder, the length of the cylinder, the temperature of the cylinder, the rotational speed of the left screw and the right screw, the processing amount per unit time, the gear ratio of the transmission interposed between the motor and the left screw and the right screw, and the configuration of the left screw and the right screw, with a function corresponding to each combination.

[0104] Furthermore, the right-side screw torque derivation step may be a step in which the torque of the right-side screw is derived using a model generated by machine learning. The feature quantity may also be the motor torque.

[0105] By having a computer execute the program described in Embodiment 4, the same effects as in Embodiment 1 can be obtained.

[0106] In embodiments 1 to 4, the right screw torque is derived based on characteristic quantities related to the operating state of the molding machine, such as motor torque and left screw torque obtained by a device attached to the left screw. However, of course, the left screw torque may also be derived based on characteristic quantities related to the operating state of the molding machine, such as motor torque and right screw torque obtained by a device attached to the right screw.

[0107] Although various embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications are included. Furthermore, the embodiments described above are described in detail for the purpose of explaining the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. In addition, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Moreover, the numbers and messages included in the text and figures are merely examples, and using different ones will not impair the effects of the present invention.

[0108] Furthermore, it is possible to add, delete, or replace some of the configurations in each embodiment with other configurations. Also, some or all of the above configurations, functions, processing units, processing means, etc., may be implemented in hardware, for example, by designing them as integrated circuits. Alternatively, the above configurations, functions, etc., may be implemented in software by a processor such as an MPU or CPU interpreting and executing a program that implements each function. Furthermore, the scope of functions implemented by software is not limited, and hardware and software may be used in combination. Information such as programs, tables, and files that implement each function can be stored in memory, a recording device such as a hard disk or SSD, or a recording medium such as an IC card, SD card, or DVD. [Explanation of Symbols]

[0109] 1...Molding machine, 2...Cylinder, 3...Screw, 31...Left screw, 32...Right screw, 4...Rotation drive mechanism, 4a...Motor, 4b...Transmission, 5...Die, 6...Support base, 7...Output shaft, 71...Left output shaft, 72...Right output shaft, 8...Coupling, 9...Motor output shaft, 10...Motor torque meter, 11...Telemeter, 12...Base unit, 13...Temperature control unit, 80...Control and monitoring device, 81...Operating condition setting unit, 82...Operation control unit, 83...Motor torque acquisition unit, 84...Left screw torque acquisition unit, 85...Right screw torque output unit, 86...Torque display unit, 87...Alert notification unit, 90...Control and monitoring system, 100...Molding machine system

Claims

1. A molding machine having a cylinder, a first screw and a second screw built into the cylinder, and a motor that rotates the first screw and the second screw, A feature quantity identification device for identifying feature quantities related to the operating state of the molding machine, A torque detection device is attached to the rotating shaft of the first screw and detects the torque of the first screw, A torque derivation device that derives the torque of the second screw based on the feature quantities identified by the feature quantity identification device and the torque of the first screw detected by the torque detection device, Equipped with, The torque derivation device derives the torque of the second screw using a torque derivation function that outputs the torque of the second screw when the characteristic quantity and the torque of the first screw are input, and the torque derivation function is determined according to the operating conditions of the molding machine. Molding machine system.

2. In the molding machine system according to claim 1, The torque derivation device stores a table which associates the operating conditions with the functions to be used when the molding machine is operated under those operating conditions, and the molding machine system refers to the table to identify the function corresponding to the set operating conditions and determines the identified function as the torque derivation function.

3. In the molding machine system according to claim 2, A molding machine system, wherein the table associates combinations of multiple items, such as the raw materials to be introduced, additives to the raw materials, the mixing ratio of the materials constituting the raw materials, the diameter of the cylinder, the length of the cylinder, the temperature of the cylinder, the rotational speed of the first screw and the second screw, the processing amount per unit time, the gear ratio of the transmission interposed between the motor and the first screw and the second screw, and the configuration of the first screw and the second screw, with a function corresponding to each combination.

4. In the molding machine system according to claim 1, The torque derivation device is a molding machine system that derives the torque of the second screw using a model generated by machine learning.

5. In the molding machine system according to claim 1, A molding machine system comprising a display unit that displays the torque of the first screw or a numerical value based on the torque of the first screw, and the torque of the second screw or a numerical value based on the torque of the second screw.

6. In the molding machine system according to claim 1, A molding machine system comprising a notification unit that outputs an alert when the torque of the first screw or the torque of the second screw meets predetermined conditions.

7. In the molding machine system according to claim 1, The feature identification device is a torque meter connected to the motor, and the molding machine system detects the torque of the motor as the feature.

8. In the molding machine system according to claim 1, The feature identification device is a molding machine system that estimates the torque of the motor as the feature based on a measured value representing the operating state of the molding machine or the current supplied to the motor.

9. A torque derivation system for deriving the torque of a screw that constitutes a molding machine, Feature identification device, First screw torque acquisition device, It is equipped with a second screw torque extraction device, The molding machine comprises a cylinder, a first screw and a second screw built into the cylinder, and a motor that rotates the first screw and the second screw. The feature identification device identifies feature quantities related to the operating state of the molding machine, The first screw torque acquisition device acquires the torque of the first screw detected by a torque detection device attached to the rotating shaft of the first screw. The second screw torque derivation device derives the torque of the second screw based on the acquired torque of the motor and the torque of the first screw. The second screw torque derivation device derives the torque of the second screw using a torque derivation function that outputs the torque of the second screw when the characteristic quantity and the torque of the first screw are input, and the torque derivation function is determined according to the operating conditions of the molding machine. Torque derivation system.

10. In the torque derivation system according to claim 9, The second screw torque derivation device stores a table which associates the operating conditions with the functions to be used when the molding machine is operated under those operating conditions, for each type of operating condition. The device refers to the table to identify a function corresponding to the set operating conditions and determines the identified function as the torque derivation function.

11. In the torque derivation system according to claim 10, The aforementioned table is a torque derivation system in which a combination of multiple items, such as the raw materials introduced into the molding machine, the mixing ratio of the materials constituting the raw materials, the diameter of the cylinder, the length of the cylinder, the temperature of the cylinder, the rotational speed of the first screw and the second screw, the processing amount per unit time, the gear ratio of the transmission interposed between the motor and the first screw and the second screw, and the configuration of the first screw and the second screw, is associated with a function corresponding to each combination.

12. In the torque derivation system according to claim 9, The second screw torque derivation device is a torque derivation system that derives the torque of the second screw using a model generated by machine learning.

13. In the torque derivation system according to claim 9, A torque derivation system in which the aforementioned feature quantity is the torque of the motor.

14. A torque derivation method for deriving the torque of a screw constituting a molding machine, Feature acquisition step, The first screw torque acquisition step, Torque derivation function determination step, The second screw torque extraction step is included, The molding machine comprises a cylinder, a first screw and a second screw built into the cylinder, and a motor that rotates the first screw and the second screw. In the feature acquisition step, a process is performed to acquire the feature identified by a feature identification device that identifies feature values ​​related to the operating state of the molding machine. In the first screw torque acquisition step, a process is performed to acquire the torque of the first screw detected by a torque detection device attached to the rotation shaft of the first screw. In the second screw torque derivation step, a process is performed to derive the torque of the second screw based on the acquired feature quantities and the torque of the first screw. The process for deriving the torque of the second screw is a process for deriving the torque of the second screw using a torque derivation function that outputs the torque of the second screw when the feature quantity and the torque of the first screw are input. In the torque derivation function determination step, a process is performed to determine the torque derivation function according to the operating conditions of the molding machine. Torque derivation method.

15. In the torque derivation method according to claim 14, The torque derivation method, in the second screw torque derivation step, involves referring to a table that associates the operating conditions with the functions to be used when the molding machine is operated under those operating conditions, identifying a function corresponding to the set operating conditions, and determining the identified function as the torque derivation function.

16. In the torque derivation method according to claim 15, A torque derivation method, wherein the table associates combinations of multiple items, such as the raw materials introduced into the molding machine, the mixing ratio of the materials constituting the raw materials, the diameter of the cylinder, the length of the cylinder, the temperature of the cylinder, the rotational speed of the first screw and the second screw, the processing amount per unit time, the gear ratio of the transmission interposed between the motor and the first screw and the second screw, and the configuration of the first screw and the second screw, with a function corresponding to each combination.

17. In the torque derivation method according to claim 14, A torque derivation method comprising the second screw torque derivation step, in which the torque of the second screw is derived using a model generated by machine learning.

18. In the torque derivation method according to claim 14, A torque derivation method wherein the aforementioned feature quantity is the torque of the motor.

19. A program for deriving the torque of the screws that make up a molding machine, Feature acquisition step, The first screw torque acquisition step, Torque derivation function determination step, The second screw torque deriving step is performed by the computer, The molding machine comprises a cylinder, a first screw and a second screw built into the cylinder, and a motor that rotates the first screw and the second screw. The feature acquisition step is a step of acquiring the feature identified by a feature identification device that identifies feature values ​​related to the operating state of the molding machine, The first screw torque acquisition step is a step of acquiring the torque of the first screw detected by a torque detection device attached to the rotation shaft of the first screw, The second screw torque derivation step is a step of deriving the torque of the second screw based on the acquired feature quantities and the torque of the first screw, The step of deriving the torque of the second screw is to derive the torque of the second screw using a torque derivation function that outputs the torque of the second screw when the feature quantity and the torque of the first screw are input. The torque derivation function determination step is a step of determining the torque derivation function according to the operating conditions of the molding machine. program.

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