Injection molding machine

Abstract

To provide an injection molding machine capable of appropriately correcting a plasticizing condition.SOLUTION: An injection molding machine includes a plasticizing process of plasticizing a granular resin supplied to a heating cylinder through a hopper according to a plasticizing condition by moving a screw backward while rotating the screw, a purging process of discharging a molten resin plasticized in the plasticizing process by moving the screw forward in the heating cylinder separated from a mold, and a control unit configured to control the screw so that waveform data indicating a change in a physical quantity acquired in a process of discharging the molten resin in the purging process approaches an ideal state. A correction process of causing a pre-learned learned model to correct a plasticizing condition and an injection process of injecting a molten resin plasticized by a plasticizing process into a cavity by moving a screw forward in a heating cylinder in contact with a mold clamped are executed.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an injection molding machine that appropriately corrects plasticization conditions. [Background technology]

[0002] In order to stabilize the quality of molded products produced by injection molding machines, it is necessary to properly manage the plasticized state of the resin inside the heating cylinder. Melting To bring the resin closer to its ideal state, Melting Resin resin There is a technique for adjusting the temperature of a heater so that the viscosity falls within a predetermined range (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-035459 Summary of the Invention [Problem to be solved by the invention]

[0004] however, Melting Resin resin There are limitations to optimizing the plasticization conditions by simply referring to the instantaneous viscosity value. resin Simply adjusting the heater temperature to keep the viscosity within a specified range is not enough. , tree There is a limit to how close the plasticization state of fat can be to the ideal state.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an injection molding machine that can appropriately correct plasticization conditions. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides a mold clamping device that opens, closes, and clamps a mold, and a mold cavity that is clamped. MeltingIn an injection molding machine comprising an injection device for injecting resin, and a control device for controlling the mold clamping device and the injection device, the injection device comprises a heating cylinder whose tip is moved toward and away from the mold clamped, a screw that moves back and forth inside the heating cylinder, and a hopper that supplies granular resin to the heating cylinder, and the control device performs a plasticization process in which the granular resin supplied to the heating cylinder through the hopper is plasticized according to plasticization conditions by rotating and retracting the screw, and a control device for controlling the granular resin plasticized in the plasticization process by moving the screw forward inside the heating cylinder separated from the mold. Melting a purging process for discharging the resin; Melting A correction process is performed to correct the plasticization conditions in a trained model that has been trained in advance so that waveform data indicating changes in physical quantities obtained in the process of discharging the resin approaches an ideal state, and the screw is advanced within the heating cylinder that is in contact with the clamped mold, thereby correcting the plasticization conditions. Melting and performing an injection process of injecting a resin into the cavity. [Effects of the Invention]

[0007] According to the present invention, the plasticization conditions can be appropriately corrected. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a side view of an injection molding machine according to an embodiment of the present invention. [Figure 2] FIG. 2 is a hardware configuration diagram of an injection molding machine. [Figure 3] 10 is a flowchart of an injection control process. [Figure 4] FIG. 10 is a diagram showing an example of a plurality of waveform data. [Figure 5] 10 is a flowchart of a plasticization condition correction process. [Figure 6] FIG. 1 is a diagram illustrating a neural network included in a trained model. [Figure 7]FIG. 10 is a diagram illustrating the relationship between input data and output data of a predictive learned model. [Figure 8] FIG. 10 is a diagram showing the relationship between the position in the heating cylinder and the number of shots. DETAILED DESCRIPTION OF THE INVENTION

[0009] An injection molding machine 10 according to the present invention will be described below with reference to the drawings. The injection molding machine 10 is a device that injects a measured amount of molding material into a mold to form a molded product (hereinafter referred to as "injection molding").

[0010] [Configuration of injection molding machine 10] Fig. 1 is a side view of an injection molding machine 10 according to this embodiment. Fig. 2 is a hardware configuration diagram of the injection molding machine 10. As shown in Figs. 1 and 2, the injection molding machine 10 mainly includes a mold clamping unit 20, an injection unit 30, and a control unit 60.

[0011] The mold clamping device 20 opens, closes, and clamps the mold 21. Specifically, the mold clamping device 20 mainly includes a fixed die plate 23 that supports a fixed-side mold 22, and a movable die plate 25 that supports a movable-side mold 24. The fixed-side mold 22 and the movable-side mold 24 are supported so as to face each other in the left-right direction (horizontal direction) of the injection molding machine 10.

[0012] The movable die plate 25 moves left and right along the tie bars 27 as the driving force of the die opening / closing motor 28 is transmitted through the toggle link mechanism 26. When the movable die plate 25 moves leftward, the fixed die 22 and the movable die 24 move apart. On the other hand, when the movable die plate 25 moves rightward, the fixed die 22 and the movable die 24 come into contact with each other, forming a cavity (internal space) inside the die 21. Then, when pressure is further applied in a direction that moves the movable die plate 25 rightward, the fixed die 22 and the movable die 24 are clamped.

[0013] The injection unit 30 plasticizes, measures, and injects the molding material. The injection unit 30 according to this embodiment is disposed facing the mold clamping unit 20 in the horizontal direction (to the right of the mold clamping unit 20). The injection unit 30 mainly includes a heating cylinder 31, a screw 32, a hopper 33, and a hopper block 34.

[0014] The heating cylinder 31 is a cylindrical member extending in the left-right direction of the injection molding machine 10. The heating cylinder 31 mainly includes a resin passage 35 and a nozzle 36. In addition, a band heater 39 that heats the heating cylinder 31 is attached to the outer circumferential surface of the heating cylinder 31.

[0015] The resin passage 35 is a cylindrical space extending in the axial direction (longitudinal direction) inside the heating cylinder 31. The resin passage 35 communicates with the outside of the heating cylinder 31 (the cavity of the mold 21) through a nozzle 36 provided at the tip (front end) of the heating cylinder 31. In other words, the resin passage 35 is a space extending from the nozzle 36 along the axial direction.

[0016] The screw 32 is a cylindrical member. A groove (hereinafter referred to as a "spiral groove") extending spirally along the longitudinal direction of the screw 32 is formed on the outer circumferential surface of the screw 32. The screw 32 is housed in the internal space of the heating cylinder 31 in a state in which it can move left and right (hereinafter referred to as "forward and backward") and rotate in the injection molding machine 10. The screw 32 in the heating cylinder 31 is configured to be replaceable. In other words, screws 32 with different specifications (for example, material, shape of the spiral groove, volume of the spiral groove) can be inserted into the heating cylinder 31.

[0017] The screw 32 advances and retreats when the driving force of the injection motor 37 is transmitted thereto, and rotates when the driving force of the metering motor 38 is transmitted thereto. More specifically, when the injection motor 37 is rotated forward, the screw 32 moves (advances) toward the tip end of the heating cylinder 31 (i.e., the nozzle 36). On the other hand, when the injection motor 37 is rotated reversely, the screw 32 moves (retreats) toward the base end of the heating cylinder 31 (i.e., the side opposite the nozzle 36).

[0018] Hereinafter, within the range that the tip position of the screw 32 can reach within the heating cylinder 31, the position closest to the nozzle 36 will be referred to as the "forward limit," and the position farthest from the nozzle 36 will be referred to as the "rear limit." Furthermore, the terms "forward rotation" and "reverse rotation" of the injection motor 37 do not specify an absolute direction of rotation, but merely specify a relative relationship (i.e., forward rotation and reverse rotation are rotations in opposite directions).

[0019] The hopper 33 is a funnel-shaped member that stores granular resin as a raw material. The hopper block 34 is a member that supports the heating cylinder 31 and the hopper 33. The hopper 33 is connected to a resin passage 35 through the hopper block 34 on the base end side of the tip of the heating cylinder 31. The granular resin stored in the hopper 33 is supplied to the resin passage 35 of the heating cylinder 31 through an opening provided at the bottom end. The granular resin used in this injection molding machine 10 is, for example, so-called "pellets" molded into a cylindrical shape.

[0020] In the injection device 30, the screw 32 rotates and moves backward by rotating the injection motor 37 in the reverse direction and rotating the metering motor 38. As a result, the pellets supplied through the hopper 33 are plasticized and filled (metered) into the resin passage 35 ahead of the screw 32. In addition, in the injection device 30, the screw 32 moves forward by rotating the injection motor 37 in the forward direction.

[0021] Further, the driving force of the nozzle touch motor 40 is transmitted to the heating cylinder 31, and the nozzle 36 can be moved toward and away from the clamped mold 21. When the screw 32 is advanced in a state where the nozzle 36 is in contact with the clamped mold 21 (nozzle touch), the plasticized material ahead of the screw 32 is melted. Melting The resin is injected into the cavity of the mold 21 through the nozzle 36. On the other hand, when the screw 32 is advanced with the nozzle 36 spaced apart from the mold 21, the plasticized resin in front of the screw 32 is injected into the cavity of the mold 21. Melting The resin is discharged (purged) to the outside through the nozzle 36 .

[0022] Resins of different types (e.g., different degrees of plasticization) are supplied to the hopper 33 depending on the molded product. The particle size (size of particles) of the pellets supplied to the hopper 33 varies depending on the raw material supply device (not shown) that supplies raw material to the hopper 33. In addition to pellets, recycled resin may also be supplied to the hopper 33. Recycled resin refers to unnecessary parts (runners) separated from the molded product, resin discharged (purged) from the heating cylinder 31, etc. The ratio of pellets and recycled resin supplied to the hopper 33 gradually changes during the injection control process, which will be described later with reference to FIG. 3.

[0023] [Configuration of control device 60] 2, the control device 60 includes a CPU (Central Processing Unit) 61 and a memory 62. The memory 62 is configured, for example, with a ROM (Read Only Memory), a RAM (Random Access Memory), an HDD (Hard Disk Drive), or a combination of these. The control device 60 realizes the processing described below by having the CPU 61 read and execute program code stored in the ROM or HDD. The RAM is used as a work area when the CPU 61 executes the program.

[0024] However, the specific configuration of the control device 60 is not limited to this, and may be realized by hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array).

[0025] The control device 60 controls the overall operation of the injection molding machine 10. More specifically, the control device 60 controls the mold opening / closing motor 28, the injection motor 37, the metering motor 38, the band heater 39, the nozzle touch motor 40, and a communication IF (Interface) 68 based on various signals output from a rotary encoder 64, a load cell 65 (pressure sensor), a plurality of temperature sensors 66a, 66b, 66c, and a display / input device 67.

[0026] The mold opening / closing motor 28, the injection motor 37, the metering motor 38, and the nozzle touch motor 40 are servo motors that generate driving forces to open and close the mold 21, to move the screw 32 back and forth, to rotate the screw 32, and to move the heating cylinder 31 (nozzle 36) toward and away from the mold 21, for example, under the control of a servo amplifier (not shown).

[0027] The rotary encoder 64 is a sensor that detects the speed and tip position of the screw 32. More specifically, the rotary encoder 64 outputs pulse signals corresponding to the rotation of the injection motor 37 to the control device 60. The control device 60 then determines the speed of the screw 32 based on the number of pulse signals output per unit time. The control device 60 also determines the tip position of the screw 32 based on the cumulative value of the pulse signals.

[0028] The load cell 65 is a sensor that detects the pressure applied to the screw 32. More specifically, the load cell 65 outputs a pressure signal (voltage value) corresponding to the pressure applied to the screw 32 to the control device 60. Then, the control device 60 identifies the pressure applied to the screw 32 based on the pressure signal output from the load cell 65.

[0029] The temperature sensors 66a, 66b, and 66c detect the temperatures of each longitudinal region of the heating cylinder 31 (for example, the distal region A, the intermediate region B, and the proximal region C), and output temperature signals indicating the detected temperatures to the control device 60. That is, the band heater 39 is configured so that the temperatures of the distal region A, the intermediate region B, and the proximal region C can be set individually. The temperature sensors 66a, 66b, and 66c detect the temperatures of the distal region A, the intermediate region B, and the proximal region C, respectively.

[0030] The rotary encoder 64, the load cell 65, and the temperature sensors 66a to 66c are connected to the heating cylinder 31. Melting It is a physical quantity sensor that detects physical quantities (for example, speed, pressure, temperature) during the process of injecting or discharging the resin. Melting During the process of injecting or discharging the resin, changes in physical quantities (for example, changes due to the position of the screw 32, changes over time) are continuously detected, and a physical quantity signal indicating the detected physical quantity is output to the control device 60. However, specific examples of physical quantities that can be detected by the physical quantity sensor are not limited to the above examples, and Melting Resin resin Changes in viscosity, Melting It may also be a change in the density of the resin.

[0031] The display input device 67 is a user interface that includes a display (display device) that displays various information to be notified to the operator, and buttons, switches, dials, etc. (input devices) that accept input operations by the operator. The display input device 67 may include a touch panel superimposed on the display. The display input device 67 accepts input operations by the operator and outputs an input signal corresponding to the accepted input operation to the control device 60.

[0032] The communication IF 68 is an interface for communicating with the AI ​​server 50 via a communication network. The communication network may be, for example, the Internet, a public line, a wired LAN, a wireless LAN, or a combination of these. The control device 60 can instruct the AI ​​server 50 to perform the process of step S33 in FIG. 5 via the communication IF 68, and can receive the results of the process executed by the AI ​​server 50 via the communication IF 68. Details of the AI ​​server 50 will be described later with reference to FIGS. 6 and 7. Note that the functions of the AI ​​server 50 may be implemented in the control device 60.

[0033] The control device 60 may also communicate with the raw material supply device through the communication IF 68. More specifically, the control device 60 may receive the type of resin, the particle size of the pellets, and the proportion of recycled resin supplied to the hopper 33 from the raw material supply device through the communication IF 68. As another example, the control device 60 may accept, through the display / input device 67, an input operation by an operator to input the type of resin, the particle size of the pellets, and the proportion of recycled resin supplied to the hopper 33.

[0034] [Information set in memory 62] The memory 62 stores molding conditions for injection molding. The molding conditions are operating conditions of the injection molding machine 10 that molds the molded product. In the injection control process of FIG. 3, the control device 60 operates the injection molding machine 10 in accordance with the molding conditions stored in the memory 62. The molding conditions according to this embodiment include multiple parameters (e.g., mold opening / closing speed, cooling time, removal time, injection speed, injection stroke, heater temperature, screw rotation speed, and screw back pressure). However, the parameters included in the molding conditions are not limited to these.

[0035] The parameter "mold opening / closing speed" is the speed (mm / s) at which the mold 21 switches from one of the mold open state and mold clamped state to the other. The parameter "cooling time" is the waiting time (sec) until the mold 21 is opened after the molten resin is injected into the mold 21. The molten resin injected into the cavity of the mold 21 solidifies during this cooling time to become a molded product. The parameter "removal time" is the time (sec) required for a robot arm (not shown) to remove the molded product from the open mold 21.

[0036] The parameter "injection speed" is the forward speed (mm / s) of the screw 32 during the injection process. The parameter "injection stroke" is the forward distance (mm) of the screw 32 during the injection process. The parameter "heater temperature" is the temperature (°C) of the band heater 39 that heats the heating cylinder 31. The parameter "screw rotation speed" is the rotation speed (rpm) of the screw 32 during the plasticization process. The parameter "screw back pressure" is the pressure (MPa) applied to the screw 32 as it retracts while rotating during the plasticization process.

[0037] Among the above molding conditions, the parameters "heater temperature," "screw rotation speed," and "screw back pressure" are examples of "plasticization conditions" that plasticize the resin in the plasticization process. In other words, the plasticization conditions are part of the molding conditions. The plasticization conditions are parameters that affect the plasticization state of the resin (pellets, recycled resin) supplied through the hopper 33. For example, the higher the parameter "heater temperature," the easier it is for the resin to melt; the slower the parameter "screw rotation speed," the easier it is for the resin to melt; and the higher the parameter "back pressure," the easier it is for the resin to melt. However, the specific parameters included in the plasticization conditions are not limited to the above examples.

[0038] [Injection control processing] FIG. 3 is a flowchart of the injection control process. MeltingThis is a process for molding a molded product by injecting resin into the cavity of the clamped mold 21. The control device 60 starts the injection control process in response to, for example, a molding instruction being input through the display input device 67. The molding instruction includes, for example, the number of molded products to be molded (hereinafter referred to as the "molding number").

[0039] At the start of the injection control process, the mold 21 is opened, the nozzle 36 comes into contact with the mold 21, and the next injection material is injected into the space ahead of the screw 32 of the heating cylinder 31. Melting The resin is measured, and the resin (pellets, Semi-molten resin, Melting Resin) is filled.

[0040] In addition, before starting the injection control process, test molding of a molded product is carried out to determine the molding conditions, molding conditions (plasticization conditions) suitable for the molded product to be molded in the mold 21 are determined, and the molding conditions are input through the display input device 67 and stored in the memory 62.

[0041] First, the control device 60 closes and clamps the mold 21 by rotating the mold opening / closing motor 28 in accordance with the molding condition "mold opening / closing speed" (S11). This forms a cavity in the mold 21. The processing of step S11 is an example of mold clamping processing.

[0042] Next, after the mold clamping process (S11) is completed, the control device 60 rotates the injection motor 37 forward in accordance with the molding conditions "injection speed" and "injection stroke" to advance the screw 32 (S12). Melting Resin is injected into the cavity of the mold 21. The process of step S12 is an example of an injection process.

[0043] Furthermore, the control device 60 acquires waveform data indicating changes in pressure detected by the load cell 65 during the execution of the injection process (S12). More specifically, the control device 60 acquires waveform data indicating changes in pressure (vertical axis) according to the position (horizontal axis) of the nozzle 36 within the heating cylinder 31, as shown in FIG. 4, for example. This waveform data is characterized by reaching a peak immediately after the screw 32 starts to move forward, then stabilizing, and then oscillating near the forward limit. The control device 60 then stores the acquired waveform data in the memory 62.

[0044] Furthermore, if this is the first injection process after the execution of the plasticization condition correction process (S20) described later (S13: Yes), the control device 60 stores the waveform data acquired in step S12 as master data in the memory 62 (S14). On the other hand, if this is not the first injection process after the execution of the plasticization condition correction process (S20) described later (S13: No), the control device 60 skips the processing of step S14.

[0045] The waveform data stored as master data is data that indicates the change in physical quantity immediately after the plasticization conditions are corrected in the plasticization condition correction process (S20). That is, the waveform data stored as master data is Melting This is data showing the change in physical quantity when the plasticized state of the resin is close to the ideal state.

[0046] Next, after the injection process (S12) is completed, the control device 60 rotates and moves the screw 32 backward, thereby plasticizing the granular resin supplied to the heating cylinder 31 through the hopper 33, and then injecting the plasticized resin into the space in front of the screw 32 of the heating cylinder 31. Melting The resin is weighed (S15). The process of step S15 is an example of a plasticizing process.

[0047] After the injection process (S12) is completed, the control device 60 controls the cooling time in the cavity in accordance with the molding condition "cooling time" in parallel with the plasticization process (S15). Melting The resin is cooled (S16). MeltingThe resin is cooled to form a molded product. At this time, the control device 60 may circulate cooling water through cooling water channels provided in the mold 21. The process of step S16 is an example of a cooling process.

[0048] Next, when both the plasticizing process (S15) and the cooling process (S16) are completed (S16: Yes), the control device 60 opens the mold 21 by rotating the mold opening / closing motor 28 in accordance with the molding condition "mold opening / closing speed," and causes the robot arm to remove the molded product from the opened mold 21 in accordance with the molding condition "removal time" (S17). The process of step S17 is an example of the removal process.

[0049] Next, the control device 60 determines whether the number of molded articles molded in the injection control process has reached the molding quantity specified in the molding command (S18). If the number of molded articles has not reached the molding quantity (S18: No), the control device 60 executes the processes of steps S19 to S20, and then executes the processes of step S11 and subsequent steps again. That is, the control device 60 repeatedly executes the processes of steps S11 to S17 and S19 to S20 until the number of molded articles reaches the molding quantity.

[0050] As an example, the control device 60 skips the process of step S20 and repeatedly executes the processes of steps S11 to S17 until the injection process (S12) has been executed a predetermined number of times (predetermined number of times) (S19: No). Then, when the injection process (S12) has been executed a predetermined number of times (S19: Yes), the control device 60 executes the plasticization condition correction process (S20) and executes the processes of step S11 and subsequent steps in accordance with the plasticization conditions corrected in the plasticization condition correction process. Details of the plasticization condition correction process will be described later with reference to FIG. 5.

[0051] As another example, the control device 60 may execute the plasticization condition correction process (S20) when the variation in the waveform data acquired in the repeatedly executed injection process (S12) becomes equal to or greater than a threshold value (S19: Yes). Fig. 4 is a diagram showing an example of multiple waveform data. In Fig. 4, the multiple waveform data are distinguished by the thickness of the lines.

[0052] In the process of repeatedly executing the processes of steps S11 to S17, if the lot of pellets fed into the raw material supply device is replaced, the particle size and shape of the pellets may change. Also, recycled resin may be supplied to the hopper 33 in addition to the pellets. The ratio of pellets and recycled resin supplied to the hopper 33 gradually changes during the injection control process. As a result, when the plasticization process (S15) is repeatedly executed under the same plasticization conditions, , tree The plasticization state of the resin changes gradually, resulting in variations in the waveform data acquired in the repeatedly executed injection process (S12), as shown in FIG.

[0053] Therefore, the control device 60 may execute the plasticization condition correction process (S20) when the difference between the maximum pressure Pmax and the minimum pressure Pmin in the latter part (near the forward limit) of the plurality of waveform data becomes equal to or greater than a threshold value (S19: Yes), as shown in the enlarged view of Fig. 4. Alternatively, the control device 60 may execute the plasticization condition correction process (S20) when the area (integrated value) of the region surrounded by the latter part (near the forward limit) of the plurality of waveform data shown in the enlarged view of Fig. 4 becomes equal to or greater than a threshold value (S19: Yes). The latter part of the waveform data refers to, for example, the section on the forward limit side of the predetermined position of the nozzle 36.

[0054] Furthermore, the control device 60 ends the injection control process when the number of molded articles reaches the molding quantity (S18: Yes). As another example, the control device 60 may end the injection control process when an operator's operation to instruct the end of the injection control process is received through the display input device 67 (S18: Yes).

[0055] [Plasticization condition correction process] FIG. 5 is a flowchart of the plasticization condition correction process. The plasticization condition correction process is a process for correcting the plasticization conditions so that the waveform data acquired in the purging process approaches an ideal state. "The waveform data approaches an ideal state" means, for example, that the waveform data obtained in the purging process approaches an ideal state. Melting This means that when the resin is injected into the mold 21, the waveform data approaches the desired state (the state when the resin in the heating cylinder 31 is uniformly plasticized).

[0056] As one example, the plasticization condition correction process is a process that causes the trained model 51 to correct the plasticization conditions so that the waveform data acquired by the repeatedly executed purge process (S32) approaches the master data. As another example, it is a process that causes the trained model 51 to correct the plasticization conditions so that the variation in multiple waveform data acquired by the repeatedly executed purge process (S32) is reduced.

[0057] First, the control device 60 drives the nozzle touch motor 40 to move the nozzle 36 away from the mold 21 (S31). Next, the control device 60 rotates the injection motor 37 forward to move the screw 32 forward (S32). As a result, the measured amount of the injection material is delivered to the region in front of the screw 32 in the heating cylinder 31. Melting The resin is discharged (purged) to the outside of the injection molding machine 10 through the nozzle 36 separated from the mold 21. The process of step S32 is an example of a purging process.

[0058] Note that some or all of the operating conditions (e.g., injection speed, injection stroke) of the purging process (S32) may be the same as those of the injection process (S12). That is, the control device 60 may execute the purging process in accordance with at least some of the molding conditions. As another example, the control device 60 may execute the purging process in accordance with conditions (purging conditions) different from the molding conditions. In this case, the purging conditions are input via the display / input device 67 and stored in the memory 62.

[0059] Furthermore, the control device 60 acquires waveform data indicating changes in pressure detected by the load cell 65 during the execution of the purge process (S32). Then, the control device 60 stores the acquired waveform data in the memory 62. The basic shape of the waveform data acquired in the purge process (i.e., changes in pressure depending on the position of the nozzle 36) is common to the waveform data acquired in the injection process. On the other hand, in the purge process, Melting The resin is not affected by the internal shape (more specifically, the shape of the cavity) of the mold 21. Therefore, the waveform data acquired in the purging process may have a different absolute value of pressure or a different vibration pattern in the latter half compared to the waveform data acquired in the injection process.

[0060] Next, the control device 60 causes the trained model 51 to correct the plasticization conditions (S33) so that the waveform data acquired in the purge process (S32) approaches an ideal state. That is, the control device 60 inputs the current plasticization conditions into the trained model 51 and acquires the corrected plasticization conditions from the trained model 51. The process of step S33 is an example of the correction process. The specific contents of the correction process will be described later with reference to FIGS. 6 to 9.

[0061] Next, the control device 60 determines whether the purging process (S32) and the correction process (S33) have been performed a predetermined number of times (S34). If the control device 60 determines that the purging process and the correction process have been performed less than the predetermined number of times (S34: No), the control device 60 rotates and retracts the screw 32, thereby plasticizing the granular resin supplied to the heating cylinder 31 through the hopper 33. Melting The resin is weighed (S35). The process of step S35 is an example of a plasticizing process, and is common to step S15. That is, the control device 60 repeatedly executes the processes of steps S32 to S35 a predetermined number of times.

[0062] The predetermined number of times may be set to, for example, the number of times step S32 is executed (i.e., the number of shots) required from when the granular resin enters the heating cylinder 31 until it is discharged. However, the specific value of the predetermined number of times is not limited to the number of shots. Furthermore, the predetermined number of times is not limited to a fixed value. In other words, the control device 60 may repeatedly execute the processes of steps S32 to S35 until it can be evaluated that the plasticization conditions have approached the ideal state.

[0063] Next, when the control device 60 determines that the number of times steps S32 to S35 have been executed reaches a predetermined number (S34: Yes), it drives the injection motor 37 to repeatedly advance and retreat (suck back) the screw 32 (S36). Melting This is a process for discharging the resin. After the suck back is completed, the control device 60 drives the nozzle touch motor 40 to bring the nozzle 36 into contact with the mold 21 (S37).

[0064] [AI Server 50 Processing] Fig. 6 is a diagram showing a neural network included in the trained model 51. Fig. 7 is a diagram showing the relationship between input data and output data of the predictive trained model 51.

[0065] The AI ​​server 50 is realized by, for example, a workstation or a general-purpose computer such as a personal computer. The AI ​​server 50 realizes AI (Artificial Intelligence) including a trained model 51. The AI ​​installed in the AI ​​server 50 processes input data and outputs output data. The AI ​​installed in the AI ​​server 50 also outputs output data from the input data using, for example, a neural network shown in FIG. 6. The AI ​​server 50 according to this embodiment includes, for example, a trained model 51 that executes a correction process (S33).

[0066] As shown in Figure 6, the neural network is composed of an input layer L1 consisting of multiple nodes I1, I2, and I3, a hidden layer L2 consisting of multiple nodes H1, H2, H3, and H4, and an output layer L3 consisting of multiple nodes O1, O2, and O3. In the example of Figure 6, the number of nodes in the input layer L1 and the output layer L3 is the same, but the number of nodes in the input layer L1 and the output layer L3 may be different. The neural network may also have multiple hidden layers L2. Furthermore, Figure 6 shows a fully connected neural network in which multiple nodes in each layer L1, L2, and L3 are connected to all nodes in adjacent layers, but the structure of the neural network is not limited to this.

[0067] The trained model 51 is generated by inputting a plurality of pieces of training data, including input data and correct answer data, into a pre-training model (hereinafter referred to as the "pre-training model"). The input data refers to the data input into the pre-training model. The correct answer data refers to the data that should be output when the input data is input. Then, by inputting a plurality of pieces of training data into the pre-training model, the neural network is optimized to become the trained model 51. The training data is generated based on, for example, the results of an experiment, a simulation, or injection molding performed by the injection molding machine 10. This process is an example of a training process in which the weight coefficients and biases of each node are adjusted so that correct answer data is output from the output layer L3 when input data is input into the input layer L1.

[0068] For example, waveform data is used as input data, and training data is input to the pre-training model, with the correct data being plasticization conditions (e.g., heater temperature, screw rotation speed, and some or all of screw back pressure) that bring this waveform data (more specifically, the plasticization state identified from the waveform data) closer to the ideal state, thereby generating the trained model 51. The input data may further include some or all of the plasticization conditions, master data, resin type, pellet particle size, and recycled resin proportion.

[0069] Furthermore, the learning process may be performed not only on the pre-learning model but also on the trained model 51. Furthermore, the AI ​​does not need to learn using the input data and correct answer data actually used in the present invention, but may learn using general-purpose learning data. Furthermore, the learning process performed by the AI ​​is not limited to "supervised learning" in which input data and correct answer data are input, but may also be "unsupervised learning" in which correct answer data is not input, or may be reinforcement learning, transfer learning, or the like.

[0070] The AI ​​server 50 also generates and outputs output data by inputting input data into the neural network of the trained model 51. This process is an example of a generation process in which input data input to the input layer L1 is processed using weighting coefficients and biases adjusted in advance for each node, and output data is output from the output layer L3.

[0071] For example, in step S33, the control device 60 inputs the plasticization conditions stored in the memory 62 and the waveform data acquired in step S32 as input data, and outputs, as output data, plasticization conditions corrected so that the waveform data approaches an ideal state. Then, the control device 60 overwrites the plasticization conditions stored in the memory 62 with the corrected plasticization conditions acquired from the trained model 51.

[0072] As an example, in the repeatedly executed correction process (S33), the control device 60 may cause the trained model 51 to correct the plasticization conditions so that the waveform data acquired in the most recent purge process (S32) approaches the master data. More specifically, in the repeatedly executed correction process (S33), the control device 60 inputs the plasticization conditions and master data stored in the memory 62 and the waveform data acquired in the most recent purge process (S32) as input data, and outputs the plasticization conditions corrected so that the waveform data approaches the master data as output data.

[0073] As another example, the control device 60 may cause the trained model 51 to correct the plasticization conditions in the repeatedly executed correction process (S33) so as to reduce the variation in the waveform data acquired in the multiple purge processes (S32). More specifically, in the Nth (N is an integer of 2 or more) correction process (S33), the control device 60 inputs the plasticization conditions stored in the memory 62 and the waveform data acquired in the first to (N-1)th purge processes (S32) as input data, and outputs the corrected plasticization conditions as output data so as to reduce the variation in the (N-1) waveform data.

[0074] The input data to be input to the trained model 51 is not limited to the above-mentioned examples. For example, in the correction process (S33), the control device 60 may further input at least one of the type of resin supplied to the hopper 33, the particle size of the granular resin supplied to the hopper 33, and the proportion of recycled resin supplied to the hopper 33 to the trained model 51 as input data.

[0075] 8 is a diagram showing the relationship between the position in the heating cylinder 31 and the number of shots. As shown in FIG. 8, the heating cylinder 31 has a plurality of shots (six shots in the example of FIG. 8). Melting Then, in the first purge process (S32), the first shot of resin is filled in the area ahead of the screw 32. Melting The resin is purged. In addition, in the plasticization process (S35) performed according to the plasticization conditions corrected in step S33, the second to sixth shots are Melting The resin moves forward, and new resin is supplied from the hopper 33. Furthermore, by repeatedly executing the processes of steps S32 to S35, the resin of each shot Melting The resin is purged in turn.

[0076] Here, for example, for the second shot Melting The resin is purged after the correction process (S33) is performed once. Melting The resin is purged after the correction process (S33) is performed five times. Melting The resin is the sixth shot. Melting Compared to resin, the effect of the plasticization conditions corrected by the correction process is small. Melting If the plasticization conditions are corrected significantly based on the waveform data obtained during the resin purging process, the conditions may actually become less ideal.

[0077] Therefore, the control device 60 may further input information indicating the number of purge processes in which the waveform data was acquired (the number of purges) as input data to the trained model 51. Then, in the repeatedly executed correction process, the trained model 51 may decrease the amount of correction of the plasticization conditions as the number of purges decreases, and increase the amount of correction of the plasticization conditions as the number of purges increases.

[0078] [Effects of the embodiment] According to the above embodiment, the plasticization conditions are corrected so that the waveform data acquired in the purging process approaches an ideal state. Melting Resin resin By correcting the plasticization conditions using two-dimensional values ​​that indicate changes in physical quantities instead of instantaneous values ​​(one-dimensional values) such as viscosity, the waveform data (in other words, the plasticization state) can be brought closer to the ideal state.

[0079] Furthermore, by correcting the plasticization conditions using waveform data obtained when the nozzle 36 is separated from the mold 21 (i.e., purging process) rather than waveform data obtained when the nozzle 36 is in contact with the mold 21 (i.e., injection process), the waveform data (in other words, the plasticization state) can be brought closer to the ideal state, regardless of the shape of the mold 21 (cavity).

[0080] Furthermore, how to correct multiple parameters included in the plasticization conditions (e.g., heater temperature, screw rotation speed, screw back pressure) to bring the waveform data closer to the ideal state is extremely complicated. Therefore, by correcting the plasticization conditions using a trained model 51 that has been trained in advance, it is possible to optimize the plasticization conditions, in which multiple parameters interact in a complex manner.

[0081] Furthermore, in the above embodiment, the waveform data immediately after the correction process can be evaluated as being close to the ideal state, so this can be stored as master data, and by correcting the plasticization conditions in the next correction process so that the waveform data approaches the master data, the plasticization state can be brought closer to the ideal state.

[0082] Furthermore, variations in the waveform data indicate that the resin is not uniformly plasticized in the heating cylinder 31. Therefore, as in the above embodiment, by correcting the plasticization conditions so as to reduce variations in the waveform data obtained by repeatedly executing the purging process, , tree The plasticization state of the fat can be brought closer to the ideal state.

[0083] Furthermore, in order to perform the purging process and the correction process, it is necessary to temporarily suspend injection molding, which causes downtime for the injection molding machine 10. Therefore, by performing the purging process and the correction process at a timing when the variation in the waveform data acquired in the injection process becomes large, as in the above embodiment, it is possible to maintain an ideal plasticized state while preventing a decrease in the throughput of the injection molding machine 10.

[0084] Furthermore, changes in the plasticization state occur, for example, due to the timing of switching the pellet lot fed into the raw material supply device, or due to changes in the ratio of pellets and recycled resin fed to the hopper 33. Therefore, if the timing of executing the purge process and correction process is determined based on the number of shots (the number of times the injection process is executed), as in the above embodiment, the load of data processing for evaluating variations in waveform data can be reduced.

[0085] Furthermore, reducing the number of types of input data allows the trained model 51 to be simplified, while increasing the number of types of input data allows the plasticization state to be brought closer to the ideal state. Therefore, as in the above embodiment, by setting the waveform data acquired in the purging process and the latest plasticization conditions as required input data and setting at least one of the type of resin supplied to the hopper 33, the particle size of the granular resin supplied to the hopper 33, and the proportion of recycled resin supplied to the hopper 33 as optional input data, these can be balanced.

[0086] Furthermore, there is a close relationship (for example, a positive correlation or proportionality) between the pressure applied to the advancing screw 32 and the plasticization state of the resin in the heating cylinder 31. Therefore, as in the above embodiment, by correcting the plasticization conditions based on the waveform data of the pressure change, the plasticization state can be made even closer to the ideal state.

[0087] The above-described embodiments are merely illustrative examples of the present invention, and are not intended to limit the scope of the present invention to these embodiments. Those skilled in the art can implement the present invention in various other forms without departing from the spirit of the present invention. [Explanation of symbols]

[0088] 10...injection molding machine, 20...mold clamping device, 21...mold, 22...fixed side mold, 23...fixed die plate, 24...movable side mold, 25...movable die plate, 26...toggle link mechanism, 27...tie bar, 28...mold opening / closing motor, 30...injection unit, 31...heating cylinder, 32...screw, 33...hopper, 34...hopper block, 35...resin passage, 36...nozzle, 37...injection motor, 38...metering motor, 39...band heater, 40...nozzle touch motor, 50...AI server, 51...trained model, 60...control device, 61...CPU, 62...memory, 64...rotary encoder, 65...load cell, 66a, 66b, 66c...temperature sensor, 67...display input device, 68...communication IF

Claims

1. a mold clamping device that opens, closes, and clamps the mold; an injection device that injects a plasticized resin into the cavity of the clamped mold; an injection molding machine including the mold clamping device and a control device that controls the injection device, The injection device a heating cylinder whose tip is brought into contact with and separated from the clamped mold; a screw that moves back and forth inside the heating cylinder; a hopper that supplies granular resin to the heating cylinder, The control device a plasticization process in which the granular resin supplied to the heating cylinder through the hopper is plasticized according to plasticization conditions by retracting the screw while rotating; a purging process in which the plasticized resin plasticized in the plasticizing process is discharged by advancing the screw within the heating cylinder spaced apart from the mold; a correction process for correcting the plasticization conditions in a trained model that has been trained in advance so that waveform data indicating changes in physical quantities acquired in the process of discharging the plasticized resin in the purging process approaches an ideal state; and performing an injection process in which the plasticized resin plasticized in the plasticizing process is injected into the cavity by advancing the screw within the heating cylinder in contact with the clamped mold.

2. 2. The injection molding machine according to claim 1, The control device The waveform data acquired in the first injection process after the correction process is executed is stored as master data, Repeating the correction process, the plasticization process according to the plasticization conditions corrected by the correction process, and the purging process; In the correction process that is repeatedly executed, the trained model corrects the plasticization conditions so that the waveform data acquired in the most recent purge process approaches the master data.

3. 2. The injection molding machine according to claim 1, The control device Repeating the correction process, the plasticization process according to the plasticization conditions corrected by the correction process, and the purging process; In the correction process that is repeatedly executed, the trained model corrects the plasticization conditions so that variation in the waveform data acquired in multiple purge processes is reduced.

4. 2. The injection molding machine according to claim 1, The control device executes the purge process and the correction process when variation in the waveform data acquired during the repeatedly executed injection process reaches or exceeds a threshold value.

5. 2. The injection molding machine according to claim 1, The control device executes the purge process and the correction process when the injection process has been executed a predetermined number of times.

6. 2. The injection molding machine according to claim 1, In the correction process, the control device The waveform data acquired in the purging process and the latest plasticization conditions are input as input data into the trained model; An injection molding machine characterized in that the corrected plasticization conditions are obtained as output data from the trained model.

7. 7. The injection molding machine according to claim 6, The control device is characterized in that, in the correction process, it further inputs at least one of the type of resin supplied to the hopper, the particle size of the granular resin supplied to the hopper, and the proportion of recycled resin supplied to the hopper into the trained model as input data.

8. 2. The injection molding machine according to claim 1, The control device acquires the waveform data indicating a change in pressure applied to the advancing screw during the purging process.

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