Plasticization condition diagnostic device for injection molding machines

Abstract

To achieve compactness while avoiding complexity by optimizing space utilization in limited installation areas, by reducing manufacturing man-hours and costs.SOLUTION: In constituting a plasticizing state diagnostic device 1 for an injection molding machine M, which diagnoses the plasticizing state of molding material R supplied from a material supply section 4 provided at the rear of a heating cylinder 2 heated by a heating section 3f and plasticized within said heating cylinder 2 by rotation of a screw 5, the device comprises an AE sensor 6 integrally provided with a temperature sensor 9 mounted on the heating cylinder 2 to detect the heating temperature of said heating cylinder 2, and a diagnostic processing unit 7 that diagnoses the plasticization state of the molding material R based on the detection results of the AE sensor 6.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a plasticization state diagnosis device for an injection molding machine that is suitable for use when plasticizing a molding material supplied to the inside of a heating barrel by rotation of a screw. [Background technology]

[0002] Generally, the injection unit of an injection molding machine has a function of plasticizing, by the rotation of a screw, molding material (pellets, etc.) supplied into the heating barrel from a material supply unit located at the rear of the heating barrel heated by a heating unit. For this reason, accurately understanding the plasticization state of the molding material inside the heating barrel is important from the viewpoint of avoiding molding defects and ensuring high molding quality, and various monitoring devices have been proposed to understand the plasticization state.

[0003] A known example of this type of monitoring device is a material monitoring device for an injection molding machine proposed by the present applicant and described in Patent Document 1. The material monitoring device described in Patent Document 1 aims to quickly identify the cause of a poor melting state and take countermeasures, as well as to prevent poor plasticization and achieve an ideal plasticization process. Specifically, the material monitoring device includes an acoustic emission wave sensor that detects acoustic emission waves generated when the molding material is deformed or sheared inside the heating barrel by the rotation of a screw, and converts the acoustic emission waves into an electric signal; an acoustic emission detection unit that detects quantitative acoustic emission data related to the deformation or shear of the molding material from the electric signal; and a material response processing function unit that performs predetermined material response processing based on the acoustic emission data. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-111091 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the material monitoring device described in the above-mentioned Patent Document 1 has the following problems to be solved.

[0006] That is, by placing it at the rear of the heating barrel, an acoustic emission wave detection sensor (AE sensor) is used which senses the acoustic emission waves generated when the molding material is deformed or sheared inside the heating barrel and converts them into an electrical signal. This has the advantage of being able to detect quantitative acoustic emission data related to the deformation or shearing of the molding material from this electrical signal, but because the detection is quantitative and localized, it has the drawback that it is not necessarily sufficient from the perspective of obtaining more specific and practical information, such as where in the heating barrel the sound is being generated or what the cause of the sound is.

[0007] For this reason, there was room for further improvement in terms of securing plasticization information from a planar (three-dimensional) and even qualitative perspective for the heating barrel, and realizing a more practical, convenient, and easy-to-use monitoring device (plasticization state diagnosis device).

[0008] SUMMARY OF THE INVENTION An object of the present invention is to provide a plasticization state diagnosis device for an injection molding machine that solves the problems present in the background art. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the present invention provides a plasticization state diagnosis device 1 for an injection molding machine M that diagnoses the plasticization state of a molding material R supplied from a material supply section 4 provided at the rear of a heating barrel 2 heated by heating sections 3f... into the interior of the heating barrel 2 when the molding material R is plasticized by the rotation of a screw 5. The device is characterized by comprising an AE sensor 6 that detects AE waves We and is integrally provided with a temperature sensor 9 that detects the heating temperature of the heating barrel 2 and is attached to the heating barrel 2, and a diagnostic processing section 7 that diagnoses the plasticization state of the molding material R based on the detection results of the AE sensor 6.

[0010] Furthermore, according to a preferred embodiment of the present invention, the temperature sensor 9 is provided with a sensor mounting portion 11 that is attached to the outer peripheral surface 2x of the heating barrel 2, and an insertion hole 11h is formed in this sensor mounting portion 11, and the tip 11ms of the waveguide rod 11m that supports the AE sensor 6 can be inserted into this insertion hole 11h for installation. In this case, the AE sensor 6 includes a first AE sensor 6r and a second AE sensor 6f, and the first AE sensor 6r can be disposed at a first position Xr on the rear side of the heating barrel 2, and the second AE sensor 6f can be disposed at a second position Xf that is forward of the first position Xr. On the other hand, the diagnostic processing unit 7 may be provided with a data processing unit 7 having a position calculation processing unit Ex that determines position data Dx related to the generation position of the AE wave We based on the arrival times tf, tr of the AE wave We obtained from each AE sensor 6f, 6r, an attack number calculation processing unit Ea that determines the number of times that the AE wave signals Sre, Sfe related to the AE wave We generated during a predetermined sampling period Tp and for each predetermined piece of position data Dx... exceed a predetermined threshold L as attack number data Da..., and an event counting processing unit Ee that determines the number of AE wave components Sp... that exceed the predetermined threshold L as event count data De.... Furthermore, the diagnostic processing unit 7 may be provided with a graphic display unit 8 that displays the occurrence pattern Ps of the attack number data Da... and the event count data De... for the position data Dx... in a graphical format. [Effects of the Invention]

[0011] The plasticization state diagnosis device 1 for the injection molding machine M according to the present invention provides the following significant effects.

[0012] (1) The AE sensor 6 that detects AE waves We is provided integrally with the temperature sensor 9 that is attached to the heating barrel 2 and detects the heating temperature of the heating barrel 2, and the diagnostic processing unit 7 that diagnoses the plasticization state of the molding material R based on the detection result of the AE sensor 6, so the AE sensor 6 can be provided integrally with the temperature sensor 9. As a result, the multiple temperature sensors 9... that are provided on the outer peripheral surface of the heating barrel 2 save space in the limited installation space, making it possible to reduce the size and further avoid complexity, and also to reduce the number of manufacturing steps and manufacturing costs.

[0013] (2) In a preferred embodiment, the temperature sensor 9 is provided with a sensor mounting portion 11 that is attached to the outer peripheral surface 2x of the heating cylinder 2, and an insertion hole 11h is formed in this sensor mounting portion 11. The tip 11ms of the waveguide rod 11m that supports the AE sensor 6 is inserted into this insertion hole 11h. This allows the sensor mounting portion 11 to be used as a single component that can be used to mount both the AE sensor 6 and the temperature sensor 9. This ensures the integrity of the component and also contributes to improved positional accuracy.

[0014] (3) In a preferred embodiment, the AE sensor 6 is composed of a first AE sensor 6r and a second AE sensor 6f, and the first AE sensor 6r is disposed at a first position Xr on the rear side of the heating barrel 2, and the second AE sensor 6f is disposed at a second position Xf in the heating barrel 2 that is forward of the first position Xr. This makes it possible to detect accurate positional information such as the location in the heating barrel 2 where the AE wave We is generated, and also makes it possible to detect a series of states from when the solid state of pellets or the like changes to when the solid state ...

[0015] (4) In a preferred embodiment, when configuring the diagnostic processing unit 7, the data processing unit 7 includes a position calculation processing unit Ex that calculates position data Dx related to the generation position of the AE wave We based on the arrival times tf, tr of the AE wave We obtained from each AE sensor 6f, 6r, an attack number calculation processing unit Ea that calculates the number of times that the AE wave signals Sre, Sfe related to the AE wave We generated during a predetermined sampling period Tp and for each predetermined position data Dx... exceed a predetermined threshold L as attack number data Da..., and an event counting calculation processing unit Ee that calculates the number of AE wave components Sp... that exceed the predetermined threshold L as event count data De.... This makes it possible to accurately obtain information from a planar (three-dimensional) perspective of the heating cylinder 2, as well as from a qualitative perspective, such as the cause of the AE wave We. This makes it possible to realize a more practical, convenient, and easy-to-use plasticization state diagnostic device 1, and to perform accurate and reliable pass / fail diagnosis and trouble judgment of the plasticization state.

[0016] (5) In a preferred embodiment, if the diagnostic processing unit 7 is provided with a graphic display unit 8 that displays the occurrence pattern Ps of the attack number data Da... and the event count data De... for the position data Dx... in a graphical format, it becomes possible to display the graphic by combining general-purpose graphs such as bar graphs and line graphs, so that the plasticization state and the trouble occurrence state can be easily and quickly grasped from the generated occurrence pattern Ps. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view showing the mounting structure of an AE sensor and a temperature sensor provided in a plasticization state diagnosis device according to a preferred embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing the exterior of the plasticization state diagnosis device, in which an AE sensor is attached to a heating barrel; [Figure 3] A functional block diagram showing the overall configuration (system) of the plasticization state diagnosis device; [Figure 4] FIG. 2 is a perspective view showing a state in which the AE sensor provided in the plasticization state diagnosis device is attached to a heating barrel; [Figure 5] FIG. 2 is a perspective view showing the internal structure of an AE sensor mounting mechanism provided in the plasticization state diagnosis device; [Figure 6] An explanatory diagram of a method for installing an AE sensor and a temperature sensor provided in the plasticization state diagnosis device. [Figure 7] FIG. 4 is a cross-sectional view showing a modified example of the mounting structure of the AE sensor and the temperature sensor provided in the plasticization state diagnosis device. [Figure 8] A flowchart showing a processing procedure of the plasticization state diagnosis device using the plasticization state diagnosis device; [Figure 9] FIG. 2 is a signal waveform diagram illustrating a method for determining the location of AE wave generation using the AE wave signal obtained from the plasticization state diagnostic device; [Figure 10] 1 is a signal waveform diagram for explaining a method for determining the number of attacks and event counts using AE wave signals obtained from the plasticization state diagnostic device; [Figure 11] FIG. 2 is a diagram showing a display screen of a graphic display unit provided in the plasticization state diagnosis device; [Figure 12] FIG. 10 is a diagram showing an example of a generated pattern displayed by the graphic display unit; [Figure 13] FIG. 10 is a display screen diagram showing another example of the generation pattern displayed by the graphic display unit; [Figure 14] FIG. 10 is a display screen diagram showing another example of the generation pattern displayed by the graphic display unit; [Figure 15] FIG. 10 is a display screen diagram showing another example of the generation pattern displayed by the graphic display unit; DETAILED DESCRIPTION OF THE INVENTION

[0018] Next, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0019] First, the overall schematic configuration of an injection molding machine M equipped with a plasticization state diagnosis device 1 according to this embodiment will be described with reference to FIG.

[0020] The injection molding machine M includes an injection unit Mi shown in Fig. 2 and a mold clamping unit (not shown). The injection unit Mi is installed on the upper surface of a movable table 21 that is movable in the front-to-back direction Fs by a nozzle touch drive unit. Reference numeral 22 denotes a front support platen fixed to the front upper surface of the movable table 21, and reference numeral 23 denotes a rear support platen fixed to the rear upper surface of the movable table 21. Four guide shafts 24 are installed between the front support platen 22 and the rear support platen 23, and slide units 25 are slidably mounted on the guide shafts 24.

[0021] The rear end of the heating barrel 2 is attached to the front surface of the front support plate 22, causing the front side of the heating barrel 2 to protrude forward. The heating barrel 2 is equipped with an injection nozzle 2n at its front end and a hopper 2h at its upper rear end. The supply port at the bottom of the hopper 2h is connected to the interior of the heating barrel 2 via a vertical material supply path 26, and this material supply path 26 and the hopper 2h form the material supply section 4. Furthermore, on the outer circumferential surface of the heating barrel 2, including the injection nozzle 2n, multiple heating sections 3f, 3m, and 3r using band heaters for heating the heating barrel 2 are attached sequentially from the front to the rear in the front-to-rear direction Fs. Each heating section 3f... is attached independently and is equipped with multiple temperature sensors 9... that detect the heating temperature of each heating zone, and the molding machine controller 41 performs feedback control of the heating temperature.

[0022] A screw 5 is inserted into the heating barrel 2, and the rear end of the screw 5 extends to the rear of the front support plate 22 through an opening provided in the front support plate 22. A driven pulley 27f is rotatably attached to the front surface of the slide unit 25, and the rear end of the screw 5 is connected to the center of the driven pulley 27f. A servomotor 28 for rotating the screw is fixed to the upper surface of the slide unit 25. A drive pulley 27d is fixed to the rotating shaft of the servomotor 28, and a timing belt 27b is stretched between the drive pulley 27d and the driven pulley 27f to form a rotation transmission mechanism. A rotary encoder 30 for detecting the rotation (number of rotations) of the servomotor 28 is attached to the servomotor 28.

[0023] On the other hand, a servo motor 31 for advancing and retreating the screw is fixed to the rear surface of the rear support platen 23. In addition, the rear end of a screw portion 32s that constitutes a ball screw mechanism 32 is rotatably attached to the front surface of the rear support platen 23, and the rotating shaft of the servo motor 31 is coupled to the rear end of the screw portion 32s. A rotary encoder 33 that detects the rotation (number of rotations) of the servo motor 31 is attached to this servo motor 31. Furthermore, the front end of a nut portion 32n that constitutes the ball screw mechanism 32 is fixed to the rear surface of the slide unit 25, and the front end side of the screw portion 32s is screwed into the nut portion 32n.

[0024] On the other hand, reference numeral 41 denotes a molding machine controller that is responsible for overall control of the injection molding machine M, and has hardware such as a CPU, memory, etc., as well as computer functions having processing programs (software) for executing various control processes including various arithmetic processes and sequence control. Therefore, the above-mentioned servo motors 28, 31 and each heating section 3f... are connected to the output port of the molding machine controller 41, and the above-mentioned rotary encoders 30, 33, and further the temperature sensors 9... provided corresponding to each heating section 3f... are connected to the input port of the molding machine controller 41. The above is the basic configuration of the injection unit Mi.

[0025] Next, the configuration of the plasticization state diagnosis device 1 according to this embodiment will be specifically described with reference to FIGS.

[0026] As shown in Figures 1 to 6, the plasticization state diagnosis device 1 is equipped with a plurality of AE sensors (acoustic emission wave detection sensors) 6r, 6f using piezoelectric ceramic elements or the like to detect AE (acoustic emission) waves We, which are arranged at a plurality of different positions Xr, Xf (two in the example) in the forward / backward direction Fs in the heating cylinder 2.

[0027] In this example, two AE sensors 6r, 6f, a first AE sensor 6r and a second AE sensor 6f, are provided, which are disposed at two positions, i.e., a first position Xr and a second position Xf. In this case, as shown in Fig. 4, the first AE sensor 6r is disposed at the first position Xr near the rear end of the rear heating section 3r on the rear side of the heating barrel 2, and the second AE sensor 6f is disposed at the second position Xf in the heating barrel 2 which is forward of the first position Xr, i.e., the second position Xf near the front of the heating section 3m in the middle of the heating barrel 2.

[0028] In this case, the first position Xr near the rear end is a position where a temperature sensor 9 is placed to detect the heating temperature by the heating section 3r at the rear of the heating barrel 2, and the front position Xf is a position where a temperature sensor 9 is placed to detect the heating temperature by the heating section 3m at the middle of the heating barrel 2.

[0029] The two AE sensors 6r, 6f according to this embodiment are provided integrally with the temperature sensor 9 attached to the heating barrel 2 and detecting the heating temperature of the heating barrel 2. In this way, by configuring the AE sensor 6 with the first AE sensor 6r and the second AE sensor 6f, and by arranging the first AE sensor 6r at a first position Xr on the rear side of the heating barrel 2 and arranging the second AE sensor 6f at a second position Xf in the heating barrel 2 that is forward of the first position Xr, it is possible to detect accurate positional information such as the location in the heating barrel 2 at which the AE wave We is generated, and it is also possible to detect a series of states from when the solid state of pellets or the like changes to when the solid state changes to when the melted state occurs, and it is possible to grasp the plasticization state in the heating barrel 2 in a sufficient and optimal state.

[0030] 5 shows an AE sensor unit 6u that houses the sensor main body 6rm of the first AE sensor 6r (the same applies to the second AE sensor 6f). This AE sensor unit 6u includes a cylindrical sensor holder 52. The cylindrical sensor main body 6rm is disposed at the bottom of the interior of this sensor holder 52, and the connection leads 6rc of this sensor main body 6rm extend from the peripheral surface of the sensor holder 52 to the outside. The sensing surface 6rms, which forms the lower end surface of the sensor main body 6rm, faces the outside from the lower end of the sensor holder 52. Meanwhile, a plunger 53 is disposed at the upper side of the interior of the sensor holder 52 so as to be displaceable in the axial direction, and a coil spring 51 is attached to bias this plunger 53 downward (toward the sensor main body 6rm). As a result, the sensor main body 6rm is fixed in place by the pressure of the tip of the plunger 53, enabling stable measurements to be performed. An alumina sheet 54 is interposed between the tip of the plunger 53 and the upper end surface of the sensor main body 6rm, and an alumina sheet 55 is attached to the lower end surface of the sensor main body 6rm, thereby reducing electrical noise.

[0031] The first AE sensor 6r (and the second AE sensor 6f) can be attached to the heating barrel 2 as shown in FIGS.

[0032] 6, a mounting hole 56 having a predetermined depth is formed in the outer peripheral surface 2x of the heating barrel 2 at the first position Xr described above. Then, the block-shaped sensor mounting portion 11 is coaxially fixed in this mounting hole 56. Thereafter, the rod-shaped sensor main body 9s of the temperature sensor 9 is inserted in the direction of arrow F1, i.e., inserted through the inner hole of the sensor mounting portion 11 and accommodated in the mounting hole 56, and the sensor main body 9s of the temperature sensor 9 is fixed to the sensor mounting portion 11.

[0033] 1, the temperature sensor 9 includes a housing 61 constituting a sensor main body 9s having a hollow space Sp therein, and a thermocouple 62 housed in the hollow space Sp, with the tip of the thermocouple 62 exposed to the outside from the tip of the housing 61. The sensor main body 9s extends from the middle of the housing 61 toward the tip, and the sensor attachment section 11 is fixed to the middle of the housing 61. In addition, in the temperature sensor 9, 63 denotes a cap-shaped cover that covers the upper opening of the housing 61, 64 denotes a spring that urges the thermocouple 62 downward, and 65 denotes a lead-out cable for the thermocouple 62.

[0034] 1, the first AE sensor 6r is composed of the above-mentioned AE sensor unit 6u and waveguide rod unit 66. The waveguide rod unit 66 includes a single round rod-shaped waveguide rod 11m and a disk-shaped mounting plate 11c fixed integrally to the upper end (rear end) of this waveguide rod 11m, and the lower surface 52d of the sensor holder 52 of the AE sensor unit 6u is fixed to the upper surface of this mounting plate 11c. As a result, the sensing surface 6rms, which is the lower end surface of the sensor main body 6rm, abuts against the upper surface of the mounting plate 11c via the above-mentioned alumina sheet 55.

[0035] 6, an insertion hole 11h is formed at a predetermined angle on the side surface (outer peripheral surface) of the sensor mounting portion 11, and the tip 11ms of the waveguide rod 11m is inserted into this insertion hole 11h, i.e., inserted in the direction of arrow F2 and fixed. In this way, by providing the temperature sensor 9 with a sensor mounting portion 11 to be mounted on the outer peripheral surface 2x of the heating barrel 2, forming an insertion hole 11h in this sensor mounting portion 11, and inserting the tip 11ms of the waveguide rod 11m supporting the AE sensor 6 into this insertion hole 11h, the sensor mounting portion 11 can be used as a single component that can be used to mount both the AE sensor 6 and the temperature sensor 9, which makes it easy to ensure the integrity of the component and also contributes to improving positional accuracy.

[0036] The mounting example in Fig. 6 is just one example, and other configurations are also possible, such as that shown in Fig. 7. Fig. 7 is the same as Fig. 1 in that the AE sensor 6 is provided integrally with the temperature sensor 9 attached to the heating barrel 2, but in Fig. 7, a cylindrical fixed barrel 11e that covers the outer peripheral surface of the sensor main body 9s is attached to the sensor main body 9s of the temperature sensor 9, and a waveguide rod 11m that extends integrally from this fixed barrel 11e is provided, and the lower surface 52d of the sensor holder 52 in the AE sensor unit 6u shown in Fig. 5 is fixed to the upper end surface of this waveguide rod 11m.

[0037] 3, the first AE sensor 6r and the second AE sensor 6f connect the controller in the molding machine controller 41 to a sensor port of the main body 42 via preamplifiers 43r and 43f, respectively, and the above-mentioned temperature sensors 9... are also connected to a sensor port of the controller main body 42 via preamplifiers 44.... The controller main body 42 has built-in hardware such as a CPU, and functions as a main part of a computer system that performs various types of calculation processing and various types of control processing.

[0038] Although the example shows the case where the molding machine controller 41 is used, it is also possible to prepare a separate high-speed processing computer and provide the outputs of the first AE sensor 6r and the second AE sensor 6f to the high-speed processing computer, thereby performing the necessary analysis processing using a separate processing system.

[0039] In addition, the internal memory 42m includes a program area 42mp that stores various processing programs (software) for executing various arithmetic processing and various control processing (sequence control), as well as a data area 42md that can store various types of data (databases), and in particular, the program area 42mp includes a diagnostic processing program for implementing the plasticization state diagnosis device of this embodiment.

[0040] As a result, the molding machine controller 41 including the internal memory 42m and the controller main body 42 functions as a main part of the plasticization state diagnosis device 1, that is, as a data processing unit 7 that processes the AE wave signals Sre, Sfe obtained from each of the AE sensors 6r, 6f as shown in Fig. 3. That is, the data processing unit 7 functions as having: a position calculation processing unit Ex that determines position data Dx relating to the generation position of the AE wave We based on the arrival times tr, tf of the AE waves We obtained from each of the AE sensors 6r, 6f using a diagnosis processing program; an attack number calculation processing unit Ea that determines the number of times that the AE wave signals Sre, Sfe relating to the AE waves We generated during a predetermined sampling period Tp and for each predetermined position data Dx... exceed a predetermined threshold L as attack number data Da...; and an event counting calculation processing unit Ee that determines the quantity of AE wave components Sp... that exceed the predetermined threshold L as event counting data De....

[0041] Furthermore, the controller main body 42 is equipped with a display 42d. The display 42d comprises a display main body 42dm and a touch panel 42dt attached to the display main body 42dm. Therefore, various setting operations, selection operations, etc. can be performed using the touch panel 42dt. The display 42d constitutes a graphic display unit 8 that at least graphically displays the occurrence pattern Ps of the attack number data Da... and the event count data De... for the position data Dx....

[0042] 11 shows an example of a display screen 71 of the display 42d including the graphic display section 8. This display screen 71 has a screen configuration in which a setting section 8s is displayed on the upper side of the screen and the graphic display section 8 is displayed on the lower side of the screen.

[0043] In this case, the setting unit 8s includes a threshold setting unit 72 that sets the threshold L, a time interval setting unit 73 that sets the time interval, a data display unit 74 that displays various data values, and a switch key 75. The threshold setting unit 72 can set the thresholds L for the AE wave signals Sre and Sfe obtained from the AE sensors 6r and 6f (see FIG. 10). In this case, the thresholds L can be set to the same or different values. In this way, the thresholds L can be set to the same or different values, allowing for flexible and reliable detection of the AE wave We corresponding to different installation positions of the AE sensors 6r and 6f.

[0044] Furthermore, the threshold setting section 72 can set each threshold value L for detecting the attack number data Da and the event count data De. When setting, the display can be switched using the switch key 75. In this case, too, each threshold value L can be set to the same or different. In this way, since each threshold value L can be set to the same or different, it is possible to set a flexible and optimal threshold value L corresponding to each of the attack number data Da and the event count data De, and it is possible to obtain accurate attack number data Da and event count data De for AE waves We.

[0045] Furthermore, the sampling period Tp can be set using a value between "0" and "10" (10 seconds) in the time window setting section 73. The data display section 74 displays the bandpass frequency (frequency band), event count value, attack value, and other set and calculated values ​​used in filtering processing, and various display and setting functions can be switched using the switch key 75.

[0046] On the other hand, the graphic display unit 8 has a function to at least graphically display the occurrence pattern Ps of the attack number data Da and the event count data De relative to the position data Dx. The illustrated graphic display unit 8 is able to display in a graph format by marking the position data Dx in the front-to-rear direction Fs of the heating barrel 2 on the horizontal axis and marking the event count data De and the attack number data Da on the vertical axis. Specifically, the attack number data Da is displayed as a bar graph Ga... and the event count data De is displayed as a line graph Gs...

[0047] In this way, when constructing the graphic display unit 8, if the occurrence pattern Ps of the attack number data Da... and the event count data De... for the position data Dx... are displayed in a graphical format, a graphic display can be made by combining general-purpose graphs such as bar graphs and line graphs, and the plasticization state and trouble occurrence state can be easily and quickly grasped from the generated occurrence pattern Ps.

[0048] The methods for obtaining the position data Dx, the attack number data Da, and the event count data De will be specifically explained together with the processing procedure of the plasticization state diagnosis device 1, which will be described later.

[0049] On the other hand, the screw rotation servomotor 28 described above is connected to an output port of the controller main body 42 via a motor driver (servo amplifier) ​​45, and the rotation speed (rotational speed) of the screw rotation servomotor 28 is detected by a rotary encoder 30, and the detected rotation speed signal is given to the motor driver 45 and the controller main body 42. In addition, each of the band heaters in the heating sections 3f, 3m, 3r described above is connected to an output port of the controller main body 42 via a heater driver 46.

[0050] Next, the operation (function) of the plasticization state diagnosis device 1 according to this embodiment, including the operation of the injection unit Mi in the injection molding machine M, will be explained according to the flowchart shown in Figure 8, with reference to Figures 1 to 5 and Figures 9 to 15.

[0051] First, various setting processes required for the plasticization state diagnostic device 1 are performed using the setting section 8s on the display screen 71 of the display 42d shown in FIG. 11 (step S1).

[0052] Specifically, the threshold setting unit 72 is used to set a threshold L for the AE wave signal Sre obtained from the first AE sensor 6r displayed in CH1, and a threshold L for the AE wave signal Sfe obtained from the second AE sensor 6f displayed in CH2. The thresholds L may be the same or different. It is also possible to set a threshold L for only one of CH1 and CH2. In the example shown in FIG. 10, the threshold L is set to around 0.2 V.

[0053] The sampling period Ts is set by the counting time interval setting unit 73. In this example, it is set to about 10 seconds. Furthermore, by using the selector key 75 to select and display a setting screen, various setting values ​​can be set, such as the bandpass frequency of the bandpass filter (e.g., 20-80 kHz (plastic breakdown)) and the ON / OFF setting of a noise cancellation waveform (e.g., a registered waveform measured in advance).

[0054] Once the setting process is complete, the operation of the injection molding machine M, i.e., the molding process, is started (step S2). The molding machine controller 41 monitors the molding process while the injection molding machine M is in operation, and once the plasticizing process has started, the controller main body 42 performs an acquisition process of detection signals based on the AE waves We obtained from each of the AE sensors 6r, 6f (steps S3, S4). In this case, the detection signals obtained from each of the AE sensors 6r, 6f are amplified by preamplifiers 43r, 43f, respectively, and then sent to the controller main body 42 (step S5).

[0055] The controller main body 42 performs noise removal processing on the amplified detection signal (step S6). The noise removal processing removes noise components Np that are not related to the plasticization state inside the heating barrel 2. In this case, preset noise frequency components may be removed, or the operating sounds of the injection molding machine M may be measured in advance and registered as noise components Np..., thereby performing noise component cancellation processing. Note that, as necessary, it is possible to select a type related to the noise components Np, or to switch them on and off.

[0056] In this way, by performing noise removal processing on the detection signals obtained from the AE sensors 6r, 6f, treating the mixed signals other than those generated in conjunction with the plasticization process by the heating barrel 2 as noise components Np..., it is possible to eliminate ambient environmental noise, i.e., unnecessary noise components Np... (disturbances) other than the AE wave signals Sre, Sfe generated in conjunction with the plasticization of the molding material R, and therefore obtain more accurate AE wave signals Sre, Sfe.

[0057] The detection signal after noise removal is subjected to a filtering process that passes only the set bandpass frequency Bs (step S7). This makes it possible to extract detection signals related to specific frequencies Bs, such as the frequency band (20-80 kHz) at which the molding material R breaks or the frequency band (200-350 kHz) at which metals collide. In the example, the bandpass frequency Bs is set, but it may also be set as a bandpass frequency band having a predetermined bandwidth.

[0058] In this way, by performing a filtering process on the detection signals obtained from the AE sensors 6r, 6f, which passes only a set specific frequency Bs or a set specific frequency band, it becomes possible to identify and detect the AE wave signals Sre, Sfe obtained as the molding material R plasticizes, specifically the AE wave We when the molding material R breaks and the AE wave We when the molding material R collides with metal, thereby making it possible to more accurately diagnose the plasticization state and the occurrence of trouble.

[0059] 9 and 10 show the signal waveforms of the AE wave signals Sre and Sfe after noise removal and filtering. These signal waveforms can be displayed on a separate screen by switching the switch key 75 (steps S8 and S9).

[0060] The detection signals after the filtering process function as AE wave signals Sre and Sfe, and therefore undergo calculations related to diagnostic data processing by the data processing unit 7 shown in Fig. 3 (step S10). In this case, the calculations are performed over the sampling period Ts set by the time interval setting unit 73, which is 10 seconds in this example.

[0061] Now, let us consider a case where an AE wave We with a relatively large amplitude exceeding a threshold L occurs during a sampling period Ts, as shown in Fig. 10. In this case, first, the attack number calculation processing unit Ea performs attack number calculation processing (step S11). That is, the magnitude of the amplitude of the AE wave signal Sre (Sfe) is determined based on the threshold L, and if it exceeds the threshold L, it is determined that an attack has occurred, and the attack number data Da is "1".

[0062] Next, the event counting calculation processing unit Ee counts the number of waveform components Sp... that exceed the threshold L, and performs event counting calculation processing to obtain the event count data De (step S12). The quantity obtained by counting becomes the event count data De.

[0063] Furthermore, based on the obtained AE wave signals Sre and Sfe, the position calculation processor Ex performs calculation processing to obtain position data Dx (step S13). The position calculation processor Ex obtains position data Dx relating to the generation position of the AE wave We based on the arrival times tr and tf of the AE waves We obtained from each of the AE sensors 6r and 6f. That is, as shown in Fig. 9, a time difference Δt occurs between the AE wave signals Sre and Sfe obtained from each of the AE sensors 6r and 6f due to delay in the arrival times tr and tf. Therefore, the generation position of the AE wave We is obtained as position data Dx based on the arrangement positions Xr and Xf of each of the AE sensors 6r and 6f, the time difference Δt, and the speed of sound. Note that the longitudinal frequency of iron is used for the speed of sound.

[0064] This series of data processing links the attack number data Da, event count data De, and position data Dx together, and so temporary registration is performed in this linked state. The above is the data processing when one attack occurs. After this, even if the next attack occurs during the sampling period Ts, the attack number data Da, event count data De, and position data Dx are obtained by the same processing procedure (steps S14, S10, etc.). This series of data processing is performed until the set sampling period Ts ends.

[0065] Then, when the sampling period Ts ends, the linked attack number data Da..., event count data De..., and position data Dx... during the sampling period Ts are counted (step S15). The counted attack number data Da..., event count data De..., and position data Dx... are graphically displayed by the graphic display unit 8 as shown in Fig. 11 (step S16).

[0066] The illustrated graphic display is in the form of a graph, with the horizontal axis representing the position of the heating barrel 2 in the forward / backward direction Fs, for example, with a position range set sequentially at intervals of 20 mm. If there is position data Dx that falls within this position range, the aggregated value of the attack count data Da... corresponding to that position data Dx is displayed as a bar graph Ga, and the aggregated value of the event count data De... is displayed as a line graph Gs.

[0067] This results in the display of the generation pattern Ps using the bar graph Ga and the line graph Gs. The operator or AI (artificial intelligence) can then perform a predetermined diagnostic process on the display of this generation pattern Ps, including determining whether the plasticization state is good or bad (step S17).

[0068] Examples of various generation patterns Ps are shown in Figures 12 to 15. In this case, Figures 12 and 13 show the generation pattern Ps when "GPPS (general-purpose polystyrene) resin" is used as the molding material R and the bandpass frequency Bs is set to 50-60 [kHz], and Figure 12 shows the case when the heating temperature is set to "low temperature 170 [°C]", while Figure 13 shows the case when the heating temperature is set to "optimum temperature 200 [°C]".

[0069] The bandpass frequency Bs of 50-60 kHz is the frequency at which plastic destruction is expected. As is clear from the occurrence patterns Ps shown in Figures 12 and 13, Figure 13 shows that the attack number data Da and event count data De temporarily increase in the early stage of plasticization, indicating a normal state of plasticization, whereas Figure 12 shows that the occurrence numbers of the attack number data Da and event count data De increase and occur over a wide range in the front-to-rear direction Fs of the heating barrel 2, especially near the front end of the heating barrel 2, indicating an insufficient state of plasticization.

[0070] In addition, Figure 14 shows the occurrence pattern Ps when the basic conditions are the same as those in Figure 13, but the heating temperature is set to "high temperature 240 [°C]." As is clear from Figure 14, it can be confirmed that there is not much difference in the plasticization state compared to the "optimum temperature 200 [°C]" case shown in Figure 13.

[0071] Furthermore, in the case of Figure 15, the basic conditions are the same as in Figure 14, but the bandpass frequency Bs is set to 220 kHz. The set frequency of 200-350 kHz is the frequency at which metal-to-metal contact is expected to occur. As is clear from Figure 15, unmelted molding material R comes into contact with the screw 5 at the rear of the heating barrel 2, generating attack number data Da and event count data De, but it can be confirmed that there are almost no further occurrences, confirming that the molding material is in a normal plasticized state.

[0072] In this way, it can be confirmed that the occurrence pattern Ps displayed graphically by the graphic display unit 8 reflects the plasticization state as a pattern. Therefore, an operator or AI can perform diagnostic processing to determine whether the plasticization state is good or not, or whether a problem has occurred based on the occurrence of abnormal sounds, and further, by accumulating the occurrence patterns Ps as big data and having them learn, the diagnostic accuracy can be further improved.

[0073] The result of this diagnosis can be displayed on the display screen of the display 42d as a diagnosis result of whether the plasticization state is good or bad, or as a result of an abnormality, or can be output as a control command for necessary stop control or operation control (step S18).

[0074] Therefore, the plasticization state diagnosis device 1 for the injection molding machine M according to this embodiment basically comprises an AE sensor 6 that detects AE waves We by being provided integrally with a temperature sensor 9 that is attached to the heating barrel 2 and detects the heating temperature of the heating barrel 2, and a diagnosis processing unit 7 that diagnoses the plasticization state of the molding material R based on the detection result of the AE sensor 6, so that the AE sensor 6 can be provided integrally with the temperature sensor 9. As a result, by providing a plurality of temperature sensors 9 on the outer peripheral surface of the heating barrel 2, space can be saved in the limited installation space, making it possible to reduce the size and complexity, and also to reduce the number of manufacturing steps and manufacturing costs.

[0075] Furthermore, with the plasticization state diagnosis device 1 according to this embodiment, it is possible to accurately obtain information from a planar (three-dimensional) perspective of the heating cylinder 2, as well as from a qualitative perspective, such as where in the heating cylinder 2 the AE waves We are generated and what is the cause of the AE waves We. This makes it possible to realize a plasticization state diagnosis device 1 that is more practical, convenient, and easy to use, and enables accurate and reliable quality diagnosis and trouble determination of the plasticization state.

[0076] Although the preferred embodiment has been described in detail above, the present invention is not limited to such an embodiment, and the detailed configuration, shape, quantity, etc. can be changed, added, or deleted as desired within the scope that does not deviate from the gist of the present invention.

[0077] For example, the specific configuration in which the AE sensor 6 is integrally provided with the temperature sensor 9 can be implemented in various forms as long as it has the same function and produces the same effect. Furthermore, while the AE sensors 6r... are disposed at two locations, the rear and front, of the heating barrel 2, in the above example, the AE sensors 6r... can generally be disposed at two or more different locations. Furthermore, the rear and front sides of the heating barrel 2 on which the AE sensors 6r, 6f are disposed indicate relative positions, not absolute positions. Therefore, the "front" position means being forward of the "rear" position, and does not necessarily mean being at the front of the heating barrel 2 as an absolute position; it may be located in the middle or rear of the heating barrel 2. Meanwhile, noise removal and filtering are desirable but not essential components. Furthermore, while the graphic display unit 8 preferably displays the occurrence pattern Ps of the attack count data Da... and the event count data De... relative to the position data Dx... in a graphical format, various other graphic formats are possible as long as the occurrence pattern Ps can be visualized graphically. [Industrial Applicability]

[0078] The plasticization state diagnosis device according to the present invention can be used in various injection molding machines that plasticize molding material supplied to the inside of a heating barrel by rotation of a screw. [Explanation of symbols]

[0079] 1: plasticization state diagnosis device, 2: heating barrel, 2x: outer surface of heating barrel, 3f...: heating section, 4: material supply section, 5: screw, 6: AE sensor, 6r: first AE sensor, 6f: second AE sensor, 7: diagnosis processing section, 8: graphic display section, 9: temperature sensor, 11: sensor mounting section, 11h: insertion hole section, 11m: waveguide rod, 11ms: tip of waveguide rod, R: molding material, M: injection molding machine, We: AE wave, Xr: first position, Xf: second position, tr: arrival time, tf: arrival time, Ex: position calculation processing section, Sre: AE wave signal, Sfe: AE wave signal, L: threshold, Ea: attack number calculation processing section, Ee: event count calculation processing section, Ps: occurrence pattern

Claims

1. A plasticization state diagnosis device for an injection molding machine that diagnoses the plasticization state of a molding material when the molding material is supplied into the interior of a heating barrel from a material supply unit provided at the rear of the heating barrel, which is heated by a heating unit, and is plasticized by the rotation of a screw, is characterized in that it comprises: an AE sensor that detects AE waves and is provided integrally with a temperature sensor that is attached to the heating barrel and detects the heating temperature of the heating barrel; and a diagnosis processing unit that diagnoses the plasticization state of the molding material based on the detection result of the AE sensor.

2. 2. The plasticization state diagnosis device for an injection molding machine according to claim 1, wherein the temperature sensor comprises a sensor mounting portion to be attached to the outer peripheral surface of the heating barrel, an insertion hole portion is formed in the sensor mounting portion, and a tip of a waveguide rod having the AE sensor is inserted into the insertion hole portion for installation.

3. 4. The plasticization state diagnosis device for an injection molding machine according to claim 3, wherein the AE sensor comprises a first AE sensor and a second AE sensor, the first AE sensor being disposed at a first position on the rear side of the heating barrel, and the second AE sensor being disposed at a second position on the heating barrel that is forward of the first position.

4. 4. The plasticization state diagnosis device for an injection molding machine according to claim 3, wherein the diagnosis processing section comprises a data processing section having a position calculation processing section which determines position data relating to the generation position of the AE wave based on the arrival time of the AE wave obtained from each AE sensor, an attack number calculation processing section which determines the number of times that an AE wave signal relating to the AE wave generated during a predetermined sampling period and for each predetermined piece of position data exceeds a predetermined threshold as attack number data, and an event count calculation processing section which determines the number of the AE wave components which exceed a predetermined threshold as event count data.

5. 5. The plasticization state diagnosis device for an injection molding machine according to claim 4, wherein the diagnosis processing unit includes a graphic display unit that displays the occurrence pattern of the attack number data and the event count data relative to the position data in a graph format.

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