Kneading state evaluation device for extrusion molding machine and kneading state evaluation method

Abstract

A kneading state evaluation device (10) evaluates a kneading state when a filler that imparts a prescribed physical property to a raw material is added and kneading is performed with a dual-shaft extrusion molding machine (30), the kneading state evaluation device comprising: a temperature distribution selection unit (61) that, on the basis of physical properties that are acquired in advance and correspond to a kneaded material kneaded at each of a plurality of temperature distributions of a barrel (32) of the dual-shaft extrusion molding machine, selects a temperature distribution of the barrel that will allow a kneaded material with desirable physical properties according to the amount of the added filler to be obtained; a temperature distribution setting unit (62) that sets the temperature distribution of the barrel to the selected temperature distribution; a kneading control unit (63) that performs kneading at the set temperature distribution of the barrel; an AE signal detection unit (64) that, when kneading is performed, detects the strength of a signal output by an AE sensor (20) installed on the surface of the barrel; and a kneading state assessment unit (65) that, if the AE signal detection unit has detected a signal strength of a prescribed value, assesses that kneading is being performed in an appropriate manner.

Description

Device and method for evaluating the mixing state of an extruder

[0001] The present invention relates to an apparatus and method for evaluating the kneading state of an extruder.

[0002] Conventionally, the mixing state of raw materials in an extruder has been determined based on, for example, the elapsed time from the start of mixing, the measurement value of a pressure sensor that measures the internal pressure of the extruder, the measurement value of a temperature sensor that measures the internal temperature of the extruder, the torque fluctuation value of the motor that drives the extruder, the current value flowing through the motor, etc. (see Patent Documents 1, 2 and 3).

[0003] Special table 2019-513177 publication JP 8-258114 publication JP 10-100235 publication

[0004] All of these conventional determination methods indirectly monitor the mixing state of the raw materials, and do not directly monitor the mixing state while the production line is in operation, i.e., in-line.

[0005] The present invention has been made in view of the above, and aims to provide an apparatus and method for evaluating the kneading state of an extruder that can directly determine the kneading state of raw materials in-line.

[0006] In order to solve the above-mentioned problems and achieve the object, the kneading state evaluation device of the present invention is a kneading state evaluation device that evaluates the kneading state when a kneaded product is produced by kneading a resin raw material and a filler that imparts predetermined physical properties to the resin raw material in an extruder, and includes a temperature distribution selection unit that selects a temperature distribution of the barrel that will give a kneaded product with desired physical properties according to the amount of filler to be added, based on physical properties corresponding to the kneaded products kneaded in each of a plurality of different patterns of temperature distribution of the barrel of the extruder, which are acquired in advance; the extrusion molding machine is characterized by comprising: a temperature distribution setting unit that sets the cloth to the temperature distribution selected by the temperature distribution selection unit; a kneading control unit that kneads the resin raw material and the filler in a state in which the temperature distribution of the barrel has been set by the temperature distribution setting unit; an AE signal detection unit that detects the signal intensity output by an AE sensor that is installed on the surface of the barrel and detects elastic waves generated inside the extrusion molding machine while the kneading control unit is kneading the resin raw material and the filler; and a kneading state determination unit that determines that proper kneading is being performed when the AE signal detection unit detects a signal intensity of a predetermined value.

[0007] In addition, the method for evaluating the mixing state of an extruder according to the present invention is characterized by comprising: a physical property measurement step of setting the temperature distribution of the barrel of the extruder to a plurality of patterns and measuring physical properties corresponding to the mixed product kneaded at each of the set plurality of temperature distributions; a kneading step of kneading the resin raw material and the filler at a desired temperature distribution determined from the distribution of physical properties measured in the physical property measurement step; an AE signal acquisition step of acquiring the signal intensity output by an AE sensor installed on the surface of the barrel in the kneading step for detecting elastic waves generated inside the extruder; and a kneading state determination step of determining that proper mixing is being performed if the signal intensity acquired in the AE signal acquisition step is a predetermined value.

[0008] According to the device and method for evaluating the kneaded state of an extruder of the present invention, the kneaded state of raw materials can be directly determined in-line.

[0009] FIG. 1 is an explanatory diagram of acoustic emission. FIG. 2 is a schematic structural diagram of an AE sensor. FIG. 3 is a schematic structural diagram showing an example of a twin-screw extruder. FIG. 4 is an A-A cross-sectional view of the output shaft of the twin-screw extruder. FIG. 5 is a B-B cross-sectional view of the output shaft of the twin-screw extruder. FIG. 6 is a hardware block diagram showing an example of the hardware configuration of a mixing state evaluation device for a twin-screw extruder according to an embodiment. FIG. 7 is a diagram showing an example of setting the temperature distribution of the barrel in a twin-screw extruder. FIG. 8 is a diagram showing an example of measurement results of the thermal conductivity of a kneaded product obtained when a resin raw material and a filler are kneaded at different temperature distributions. FIG. 9 is a diagram showing an example of AE signal intensity generated when a resin raw material and a filler are kneaded at different temperature distributions. FIG. 10 is a functional block diagram showing an example of the functional configuration of a mixing state evaluation device for a twin-screw extruder according to an embodiment. FIG. 11 is a flowchart showing an example of the flow of processing performed by the mixing state evaluation device for a twin-screw extruder according to an embodiment.

[0010] (Explanation of Acoustic Emission (AE)) Before describing the embodiments, acoustic emission (hereinafter referred to as AE) used to detect the mixing state of an extruder during operation will be described. AE is a phenomenon in which, for example, when resin raw material (pellets) is mixed in an extruder, resin pellets, which are solid materials, are crushed, and accumulated strain energy is released as sound waves (elastic waves, AE waves). By detecting and analyzing the AE waves generated as the pellets are crushed, it is possible to evaluate the mixing state of the pellets and filler introduced into the extruder. The frequency band of AE waves is said to be on the order of several tens of kHz to several MHz, a frequency band that cannot be detected by general vibration sensors or acceleration sensors. Therefore, a dedicated AE sensor is used to detect AE waves. AE sensors will be described in detail later.

[0011] Fig. 1 is an explanatory diagram of acoustic emission. As shown in Fig. 1, when pellets are crushed at point P inside a twin-screw extruder 30, AE waves W are generated. The AE waves W spread radially from point P and penetrate into the housing (barrel) of the twin-screw extruder 30. The AE waves W that have penetrated into the barrel then propagate inside the barrel of the twin-screw extruder 30.

[0012] The AE wave W propagated inside the barrel of the twin-screw extruder 30 is detected by the AE sensor 20 installed on the surface of the barrel of the twin-screw extruder 30. The AE sensor 20 outputs a detection signal D. Since the detection signal D is a signal representing vibration, it is an AC signal having positive and negative values ​​as shown in Figure 1. Since it is difficult to handle the detection signal D (AE wave W) as it is when performing various calculations, it is common to handle it as a rectified waveform in which the negative portion of the detection signal D is half-wave rectified.

[0013] The propagation speed of AE waves W differs between longitudinal waves and shear waves (longitudinal waves are faster than shear waves), but considering the size (propagation distance) of the twin-screw extruder 30, this difference can be ignored. Therefore, in this embodiment, the AE waves W detected within a specified time are used as the measurement signal for analysis, regardless of whether they are longitudinal waves or shear waves.

[0014] Fig. 2 is a schematic structural diagram of an AE sensor. As shown in Fig. 2, the AE sensor 20 is enclosed in a shield case 20a and is installed at the tip of a waveguide rod 21 (waveguide) that is installed in contact with the surface of a barrel 32 of a twin-screw extruder 30, which is the detection target. The waveguide rod 21 is made of ceramic or stainless steel, and transmits the AE wave W that has propagated inside the barrel 32 to the AE sensor 20.

[0015] A heater 39 for melting pellets is attached to the outer peripheral surface of the barrel 32 of the twin-screw extruder 30, and because the temperature reaches a high level of approximately 200°C, the AE sensor 20 cannot be installed directly on the barrel 32. For this reason, the AE sensor 20 is installed via a waveguide rod 21. A magnet 22 is attached to the tip of the waveguide rod 21 on the twin-screw extruder 30 side, and the waveguide rod 21 is fixed to the surface of the barrel 32 of the twin-screw extruder 30 by the magnet 22, avoiding the position of the heater 39. Alternatively, the tip of the waveguide rod 21 may be fixed to the surface of the barrel 32 by a screw.

[0016] The other end of the waveguide rod 21 is connected to the wave-receiving surface 20b of the AE sensor 20. Note that grease may be applied to the wave-receiving surface 20b of the AE sensor 20 to improve adhesion between the AE sensor 20 and the waveguide rod 21. A vapor-deposited film 20c made of copper or the like is formed on the upper part of the wave-receiving surface 20b. A piezoelectric element 20d made of lead zirconate titanate (PZT) or the like is disposed on top of the vapor-deposited film 20c. The piezoelectric element 20d receives the AE waves W transmitted through the inside of the waveguide rod 21 via the wave-receiving surface 20b and outputs an electrical signal corresponding to the AE waves W. The electrical signal output by the piezoelectric element 20d is output as a detection signal D via the vapor-deposited film 20e and connector 20f. Note that because the detection signal D is weak, a preamplifier (not shown) may be disposed inside the AE sensor 20 to pre-amplify the detection signal D before outputting it in order to suppress the influence of noise contamination.

[0017] Hereinafter, embodiments of the device for evaluating the kneading state of an extruder according to the present disclosure will be described in detail with reference to the drawings. However, the present invention is not limited to these embodiments. Furthermore, the components in the following embodiments include those that are replaceable and easily conceivable by a person skilled in the art, or those that are substantially the same.

[0018] An embodiment of the present disclosure is an example of a twin-screw extruder mixing state evaluation device that determines the mixing state of a resin raw material and a filler. Note that the twin-screw extruder is just one example, and the present embodiment is applicable to all extruders, such as single-screw extruders and multi-screw extruders.

[0019] (Schematic Structure of Twin-Screw Extruder) First, the schematic structure of the twin-screw extruder 30 in this embodiment will be described with reference to Figures 3, 4, and 5. Figure 3 is a schematic structural diagram showing an example of a twin-screw extruder. Figure 4 is an A-A cross-sectional view of the output shaft of the twin-screw extruder. Figure 5 is a B-B cross-sectional view of the output shaft of the twin-screw extruder.

[0020] The twin-screw extruder 30 is driven according to the output of the gearbox 40. More specifically, the gearbox 40 reduces the rotational drive force of the motor 24 to rotate two output shafts 42 of the twin-screw extruder 30 in the same direction. A screw 44 and a kneading disk 46, which will be described later, are mounted on the outer periphery of the output shaft 42. The twin-screw extruder 30 plasticizes and melts the input resin raw material (resin pellets) in accordance with the rotation of the output shaft 42, kneading and molding the material, and also mixes and kneads a filler into the resin raw material to impart predetermined physical properties to the resin raw material. In this embodiment, an example is described in which boron nitride (BN) is mixed and kneaded into resin pellets (polypropylene, hereinafter referred to as PP) to produce a kneaded material with high thermal conductivity. The twin-screw extruder 30 is an example of an extruder in this disclosure.

[0021] In the twin-screw extruder 30, the two output shafts 42 are arranged parallel to each other along the X axis, with a fixed inter-shaft distance C between them, inside the cylindrical barrel 32 of the twin-screw extruder 30.

[0022] 4 is a cross-sectional view taken along line A-A of the twin-screw extruder 30. As shown in FIG. 4, the output shaft 42 is inserted into a spline hole 43 formed in the screw 44. The output shaft 42 then engages with the spline hole 43, thereby rotating the screw 44 inside the insertion hole 34.

[0023] Fig. 5 is a cross-sectional view taken along the line B-B of the twin-screw extruder 30. As shown in Fig. 5, the output shaft 42 is inserted into a spline hole 43 formed in the kneading disc 46. The output shaft 42 then engages with the spline hole 43, thereby rotating the kneading disc 46 inside the insertion hole 34.

[0024] The screws 44 rotate at a speed of, for example, 300 revolutions per minute, thereby transporting the resin raw material fed into the twin-screw extruder 30 and the filler mixed in the resin raw material to the downstream side of the twin-screw extruder 30. The screws 44 provided on each output shaft 42 also mesh with each other to promote the transport of the resin raw material and the filler.

[0025] A heater 39 is provided along the X-axis on the outer circumferential surface of the barrel 32. The heater 39 sets the temperature of the barrel 32 to a temperature that corresponds to the position in the X direction. As a result, the resin raw material fed into the twin-screw extruder 30 is melted by the heat generated by the heater 39 as it is transported downstream.

[0026] The kneading disc 46 has a structure in which multiple elliptical discs are arranged in a direction perpendicular to the output shaft 42, with the orientation of adjacent discs offset along the output shaft 42. By arranging adjacent discs in an offset manner, the flow of the resin raw material is divided between the discs, thereby promoting kneading of the transported resin raw material and filler. That is, the kneading disc 46 is heated by the heater 39, and imparts shear energy to the resin raw material transported by the screw 44, thereby completely melting the resin raw material.

[0027] The barrel 32 has an insertion hole 34 through which each output shaft 42 is inserted. The insertion hole 34 is a hole provided along the longitudinal direction (X direction) of the barrel 32, and has a shape of two cylinders partially overlapping each other. This allows the screw 44 and the kneading disk 46 to be inserted into the insertion hole 34 in a state of meshing with each other.

[0028] 3 , one end of the barrel 32 in the longitudinal direction (X direction) is provided with a supply port 36a for feeding pellet-shaped resin raw material to be kneaded into the insertion holes 34. Then, a filler is fed from a supply port 36b provided in a side feeder 37 downstream of the supply port 36a. Note that the direction in which the raw material is fed through the supply ports 36a and 36b is not limited to the example shown in FIG.

[0029] The other end of the barrel 32 in the longitudinal direction (X direction) is provided with a discharge port 38 for discharging the material kneaded while passing through the insertion hole 34 .

[0030] In the example of Fig. 3, the output shaft 42 of the twin-screw extruder 30 is provided with two screws 44 and one kneading disc 46, but the number of screws 44 and kneading discs 46 is not limited to the example shown in Fig. 3. For example, kneading discs 46 may be provided at multiple locations to knead the resin raw material and the filler.

[0031] The AE sensor 20 is installed by a magnet 22 via a waveguide rod 21 on the surface of the barrel 32 of the twin-screw extruder 30 in the vicinity of the kneading disk 46. The output of the AE sensor 20 is input to the kneading state evaluation device 10. The configuration and function of the AE sensor 20 are as described above.

[0032] The kneading state evaluation device 10 analyzes the intensity (power) of the AE waves W output by the AE sensor 20 to determine whether the kneading state of the resin raw material and filler fed into the twin-screw extruder 30 is good. A specific method for determining the kneading state will be described later.

[0033] (Hardware Configuration of Mixing State Evaluating Device) The hardware configuration of the mixing state evaluating device 10 will be described with reference to Fig. 6. Fig. 6 is a hardware block diagram showing an example of the hardware configuration of the mixing state evaluating device for a twin-screw extruder according to an embodiment.

[0034] The kneading state evaluation device 10 is used in connection with a twin-screw extruder 30. The kneading state evaluation device 10 includes a control unit 11, a storage unit 12, and an I / O controller .

[0035] The control unit 11 controls the overall operation of the kneading state evaluation device 10. The control unit 11 includes a CPU (Central Processing Unit) 11a, a ROM (Read Only Memory) 11b, and a RAM (Random Access Memory) 11c. The CPU 11a is connected to the ROM 11b and the RAM 11c via a bus line 13. The CPU 11a reads out a control program 12a stored in the storage unit 12 and loads it into the RAM 11c. The CPU 11a operates in accordance with the control program 12a loaded into the RAM 11c, thereby controlling the operation of the control unit 11. In other words, the control unit 11 has the configuration of a general computer that operates based on the control program 12a.

[0036] The control unit 11 is further connected to a storage unit 12 and an I / O controller 14 via a bus line 13 .

[0037] The storage unit 12 is configured with a nonvolatile memory such as a flash memory, which retains stored information even when the power is turned off, or a hard disk drive (HDD), etc. The storage unit 12 stores a control program 12 a, physical property measurement data 12 b, and AE signal measurement data 12 c.

[0038] The control program 12a controls the overall operation of the kneading state evaluation device 10. The control program 12a may be provided by being pre-installed in the ROM 11b. Alternatively, the control program 12a may be provided by being recorded on a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, or a digital versatile disk (DVD) in a format that can be installed or executed by the control unit 11. Furthermore, the control program 12a may be provided by being stored on a computer connected to a network such as the Internet and downloaded via the network. Alternatively, the control program 12a may be provided or distributed via a network such as the Internet.

[0039] The physical property measurement data 12b is data obtained by measuring the physical properties of a kneaded product produced by kneading a resin raw material and a filler in each of a plurality of temperature distribution patterns set in advance inside the barrel 32 of the twin-screw extruder 30. In this embodiment, the physical property measurement data 12b is data obtained by measuring the thermal conductivity of a kneaded product produced when BN is mixed and kneaded into PP. The physical property measurement data 12b will be described in detail later (see FIG. 8).

[0040] The AE signal measurement data 12c is data indicating the intensity of the AE waves W detected by the AE sensor 20 during kneading, measured at each of a plurality of temperature distributions in which PP and BN were kneaded when measuring the physical property measurement data 12b. The AE signal measurement data 12c will be described in detail later (see FIG. 9).

[0041] The I / O controller 14 controls input and output of information required when the control unit 11 of the kneading state evaluating device 10 operates according to the control program 12a.

[0042] The I / O controller 14 is connected to an AE sensor 20 , a barrel temperature controller 15 , an extruder controller 16 , and an alarm device 17 .

[0043] The AE sensor 20 is as described above.

[0044] The barrel temperature controller 15 is a controller that controls the temperature distribution of a heater 39 that is installed along the X-axis in Fig. 3 on the outer periphery of the barrel 32. The barrel temperature controller 15 controls the temperature distribution of the heater 39 in response to instructions from the control unit 11, thereby controlling the temperature of the barrel 32 of the twin-screw extruder 30 to a predetermined temperature distribution. This will be described in detail later (see Fig. 7).

[0045] The extruder controller 16 receives instructions from the control unit 11 and controls the operation of the twin-screw extruder 30 by controlling the rotation speed of the output shaft 42 and the like via the motor 24 and the gearbox 40 .

[0046] The notification device 17 notifies the evaluation result of the kneading state of the kneaded material in response to an instruction from the control unit 11. The notification device 17 may be a visual display device such as a display, or an audio display device such as a speaker or a buzzer.

[0047] (Example of Setting Temperature Distribution of Barrel) An example of setting the temperature distribution of the barrel 32 of the twin-screw extruder 30 will be described with reference to Fig. 7. Fig. 7 is a diagram showing an example of setting the temperature distribution of the barrel in the twin-screw extruder.

[0048] As described above, the twin-screw extruder 30 is provided with a heater 39 along the X-axis on the outer circumferential surface of the barrel 32. The heater 39 sets the temperature distribution of the barrel 32 along the X-axis in accordance with instructions from the barrel temperature controller 15. The barrel temperature controller 15 can set the set temperature of the heater 39 independently for each portion along the X-axis. Although not shown, the temperature of the barrel 32 is detected by temperature sensors installed at multiple positions along the X-axis. The barrel temperature controller 15 controls the output of the heater 39 for each portion along the X-axis so that the temperature distribution measured by the temperature sensor approaches the set temperature distribution.

[0049] FIG. 7 shows an example in which the temperature distribution of the barrel 32 is set in five different ways in the twin-screw extruder 30 of the embodiment.

[0050] The heater 39 provided in the twin-screw extruder 30 can independently set the temperature at, for example, 14 positions (positions C1 to C14 in FIG. 7) along the X axis.

[0051] Under condition 1 of the temperature distribution shown in Fig. 7, in the vicinity of the supply port 36a through which PP is introduced, the barrel temperature is set to 30°C at position C1, 100°C at position C2, and 150°C at position C3. The barrel temperature is set to 195°C from position C4 to position C14. Therefore, under the temperature setting under condition 1, the PP introduced through the supply port 36a reaches the kneading disc 46 in a completely molten state. The PP is then kneaded by the kneading disc 46 together with the BN introduced through the supply port 36b.

[0052] In contrast, under condition 5 of the temperature distribution shown in Fig. 7, the barrel temperature is set to 30°C between positions C1 and C9. Then, the barrel temperature is set to 100°C at position C10, 150°C at position C11, and 195°C from positions C12 to C14. Therefore, under the temperature setting of condition 5, the PP introduced through the supply port 36a reaches the kneading disc 46 in a state where it is not completely melted. Then, the PP is kneaded by the kneading disc 46 together with the BN introduced through the supply port 36b.

[0053] Conditions 2, 3, and 4 shown in FIG. 7 differ in the length of the region where the barrel temperature is set to 195°C. Specifically, the length of the region where the barrel temperature is set to 195°C is shorter under condition 3 than under condition 2. Furthermore, the length of the region where the barrel temperature is set to 195°C is shorter under condition 4 than under condition 3. Therefore, the amount of PP that reaches the kneading disc 46 in an unmelted state is greater under condition 3 than under condition 2. Furthermore, the amount of PP that reaches the kneading disc 46 in an unmelted state is greater under condition 4 than under condition 3.

[0054] In other words, the viscosity of the PP at the position of the kneading disc 46 increases in the order of condition 1, condition 2, condition 3, condition 4, and condition 5.

[0055] (Measurement of physical properties of kneaded product) The physical properties of the kneaded product kneaded by the twin-screw extruder 30 will be described with reference to Fig. 8. Fig. 8 is a diagram showing an example of the measurement results of the thermal conductivity of the kneaded product obtained when the resin raw material and the filler are kneaded at different temperature distributions.

[0056] In this embodiment, the kneaded material produced by the twin-screw extruder 30 is polypropylene (PP) to which boron nitride (BN) has been added.

[0057] The inventors of the present invention kneaded PP and BN under the same kneading conditions for the temperature distribution of the barrel 32 under conditions 1 to 5, as explained in Fig. 7. In these experiments, the amounts of BN added were set to 10 wt % and 45 wt %.

[0058] The inventors then measured the thermal conductivity of the obtained kneaded material. Fig. 8 shows an example of physical property measurement data 12b obtained as a result of the measurement. As a result of the measurement, it was found that when the amount of BN added was 10 wt%, the thermal conductivity of the kneaded material was highest when the temperature distribution of the barrel 32 was condition 3.

[0059] On the other hand, when the amount of BN added is 45 wt %, it was found that the thermal conductivity of the kneaded material was highest when the temperature distribution of the barrel 32 was condition 2 or condition 3.

[0060] Moreover, it was found that under any temperature distribution conditions, the thermal conductivity was higher when the amount of BN added was 45 wt % than when the amount of BN added was 10 wt %.

[0061] Although the case where two amounts of BN are added, 10 wt % and 45 wt %, have been described here, the amount of BN added is not limited to these. The amount of BN added may be a weight percentage different from that exemplified in Fig. 8, or more than two amounts may be added.

[0062] The kneading state evaluating device 10 of this embodiment stores the physical property measurement data 12b shown in FIG. 8 in the storage unit 12 (see FIG. 6).

[0063] (Measurement of AE signal intensity generated during kneading) The intensity of the AE signal generated during kneading in the twin-screw extruder 30 will be described with reference to Fig. 9. Fig. 9 is a diagram showing an example of the AE signal intensity generated when the resin raw material and the filler are kneaded at different temperature distributions.

[0064] The inventors of the present invention measured the intensity of the AE signal generated when PP and BN were mixed under the same mixing conditions for each of the temperature distributions of the barrel 32 under conditions 1 to 5 described in FIG. 7 .

[0065] The AE signal intensity was calculated by frequency analysis of the signal measured by the AE sensor. More specifically, the signal measured by the AE sensor was first A / D converted at a predetermined sampling frequency to convert it into a digital signal. Then, the A / D converted digital signal was passed through a bandpass filter that cuts off signals in a frequency band caused by vibrations and the like generated by the kneading operation of the twin-screw extruder 30. The characteristics of the bandpass filter were set in advance through experiments, etc. Next, a discrete Fourier transform (DFT) was performed on the signal that had been bandpass filtered to calculate a power spectrum. The integrated value of the power spectrum was then used as the AE signal intensity. Note that the AE signal intensity shown in FIG. 9 was calculated by repeatedly measuring the AE signal to increase reliability, and the average value of the AE signal intensity calculated each time was plotted.

[0066] 9, different AE signal intensities are obtained depending on the temperature distribution conditions of the barrel 32. It is also apparent that the AE signal intensity differs depending on the amount of BN added, even under the same temperature distribution conditions.

[0067] The kneading state evaluating device 10 of this embodiment stores the AE signal measurement data 12c shown in FIG. 9 in the storage unit 12 (see FIG. 6).

[0068] 8 and the AE signal measurement data 12c shown in Fig. 9, it can be seen that in order to impart a thermal conductivity to PP according to the amount of BN added, the intensity of the AE signal generated during kneading should be the value shown in the AE signal measurement data 12c. In other words, the physical property measurement data 12b and the AE signal measurement data 12c are reference data for evaluating the kneading state when kneading is performed in the twin-screw extruder 30.

[0069] (Functional Configuration of the Mixing State Evaluation Device) The functional configuration of the mixing state evaluation device 10 of the twin-screw extruder 30 of the embodiment will be described with reference to Fig. 10. Fig. 10 is a functional block diagram showing an example of the functional configuration of the mixing state evaluation device of the twin-screw extruder of the embodiment.

[0070] The control unit 11 of the kneading state evaluation device 10 loads the control program 12a into the RAM 11c and operates it, thereby realizing, as functional units, a temperature distribution selection unit 61, a temperature distribution setting unit 62, a kneading control unit 63, an AE signal detection unit 64, a kneading state determination unit 65, and a kneading state notification unit 66 shown in Fig. 10. Note that some or all of these functional units may be realized by dedicated hardware.

[0071] The temperature distribution selection unit 61 selects a temperature distribution of the barrel 32 that will produce a kneaded product with desirable physical properties according to the amount of filler (BN in this embodiment) to be added, based on the physical properties of the kneaded products kneaded in each of a plurality of different patterns of previously acquired temperature distribution of the barrel 32 of the twin-screw extruder 30. Specifically, the temperature distribution selection unit 61 displays the physical property measurement data 12b on a display device not shown in Fig. 6 and accepts an operation by the operator to select conditions that indicate an appropriate temperature distribution of the barrel 32.

[0072] The temperature distribution setting unit 62 sets the temperature distribution of the barrel 32 of the twin-screw extruder 30 to the temperature distribution selected by the temperature distribution selection unit 61. Specifically, the temperature distribution setting unit 62 realizes the temperature distribution of the barrel 32 selected by the temperature distribution selection unit 61 by controlling the barrel temperature controller 15.

[0073] The kneading control unit 63 kneads the resin raw material and the filler in a state in which the temperature distribution of the barrel 32 of the twin-screw extruder 30 has been set by the temperature distribution setting unit 62 .

[0074] The AE signal detection unit 64 detects the signal intensity output by the AE sensor 20, which is installed on the surface of the barrel 32 and detects elastic waves generated inside the twin-screw extruder 30, while the kneading control unit 63 is kneading the resin raw material and the filler. As described above, the signal intensity is calculated as the integral value of the power spectrum calculated by applying a band-pass filter to the A / D converted output signal of the AE sensor 20 and then performing a discrete Fourier transform.

[0075] The kneading state determination unit 65 determines that proper kneading is being performed when the AE signal detection unit 64 detects a signal intensity of a predetermined value. Furthermore, the kneading state determination unit 65 determines that proper kneading is not being performed when the AE signal detection unit 64 does not detect a signal intensity of the predetermined value. The predetermined value is a value based on the signal intensity output by the AE sensor 20 when PP and BN are kneaded in the temperature distribution selected by the temperature distribution selection unit 61 in the AE signal measurement data 12c acquired in advance. More specifically, the predetermined value may be the AE signal intensity itself under conditions indicating the temperature distribution during kneading in the AE signal measurement data 12c, or may be a value within a predetermined range including the value read from the AE signal measurement data 12c.

[0076] The kneading state notification unit 66 notifies the notification device 17 that the kneading state determination unit 65 has determined that proper kneading is being performed, or that proper kneading is not being performed. Specifically, the kneading state notification unit 66 notifies the notification device 17 of the evaluation result of the kneading state of the kneaded material.

[0077] (Flow of processing performed by the kneading state evaluation device) The flow of processing performed by the kneading state evaluation device 10 of the embodiment will be described with reference to Fig. 11. Fig. 11 is a flowchart showing an example of the flow of processing performed by the kneading state evaluation device for a twin-screw extruder of the embodiment.

[0078] The kneading state determination unit 65 acquires the AE signal measurement data 12c measured in advance (step S11). As described above, the AE signal measurement data 12c is data obtained by measuring the AE signal intensity observed when the barrel 32 is set to a plurality of temperature distributions and the PP and BN are kneaded.

[0079] The temperature distribution selection unit 61 acquires physical property measurement data 12b indicating the physical property of the kneaded material measured in advance (step S12). As described above, the physical property measurement data 12b is data indicating the physical property (thermal conductivity in this embodiment) of the kneaded material formed by setting the barrel 32 to a plurality of temperature distributions and kneading PP and BN.

[0080] The temperature distribution selector 61 selects an appropriate temperature distribution for kneading PP and BN from the physical property measurement data 12b based on the operator's selection (step S13). At this time, the operator selects a temperature distribution that produces a kneaded product with the highest thermal conductivity according to the weight percent of BN added to PP. For example, in the case of the physical property measurement data 12b shown in Figure 8, condition 3 is selected when the amount of BN added is 10 weight percent, and condition 2 or condition 3 is selected when the amount of BN added is 45 weight percent.

[0081] The temperature distribution setting unit 62 instructs the barrel temperature controller to realize the temperature distribution of the barrel 32 selected in step S13 (step S14).

[0082] The kneading control unit 63 kneads the PP resin raw material and the BN filler in a state where the temperature distribution of the barrel 32 of the twin-screw extruder 30 has been set (step S15).

[0083] The AE signal detection unit 64 measures the output of the AE sensor 20 installed on the surface of the barrel 32 while the kneading control unit 63 is instructing the kneading of the resin raw material and the filler (step S16).

[0084] The AE signal detection unit 64 then calculates the AE signal strength (step S17) based on the measured output of the AE sensor 20. The method for calculating the AE signal strength is as described above.

[0085] The kneading state determination unit 65 determines whether the AE signal intensity calculated by the AE signal detection unit 64 is equal to the AE signal intensity generated when kneading is performed in the previously acquired AE signal measurement data 12c at the same temperature distribution as the temperature distribution of the barrel 32 set in step S14 (step S18). If it is determined that the AE signal intensity is equal to the AE signal intensity (step S18: Yes), the process proceeds to step S19. On the other hand, if it is not determined that the AE signal intensity is equal to the AE signal intensity (step S18: No), the process proceeds to step S20. Note that in step S18, if the AE signal intensity calculated by the AE signal detection unit 64 is within a predetermined threshold range with respect to the AE signal intensity in the previously acquired AE signal measurement data 12c, the AE signal intensity may be determined to be equal to the AE signal intensity.

[0086] If it is determined in step S18 that the AE signal intensities are equal, the mixing state notification unit 66 issues a notification that the mixing state of the twin-screw extruder 30 is good (step S19). Thereafter, the mixing state evaluation device 10 ends the process.

[0087] If it is not determined in step S18 that the AE signal intensities are equal, the mixing state notification unit 66 issues a notification that the mixing state of the twin-screw extruder 30 is poor (step S20). Thereafter, the mixing state evaluation device 10 ends the processing. Note that when a notification is issued that the mixing state of the twin-screw extruder 30 is poor, the manager of the mixing operation checks the twin-screw extruder 30, investigates the cause of the poor mixing, and takes measures.

[0088] In this embodiment, an example has been shown in which thermal conductivity is increased by adding BN to PP, but in general, various physical properties can be imparted to the resin raw material depending on the type of filler added to the resin raw material.

[0089] For example, adding calcium carbonate, talc, clay, etc. to the resin raw material can increase the amount of resin. Adding fibers (GF, CF), mica, silica, etc. to the resin raw material can improve the strength of the resin raw material. Adding CB, carbon fiber, graphite, metal powder, etc. to the resin raw material can impart electrical conductivity to the resin raw material. Adding ferrite, magnetic oxide, etc. to the resin raw material can impart magnetism to the resin raw material. Adding antimony oxide, aluminum hydroxide, magnesium hydroxide, etc. to the resin raw material can impart flame retardancy to the resin raw material. Adding glass balloons, chemical foaming agents, etc. to the resin raw material can provide insulation and weight reduction to the resin raw material. Adding wood flour, starch, recycled paper, etc. to the resin raw material can reduce the environmental impact.

[0090] Furthermore, depending on the type of additive, various functions such as piezoelectricity, vibration damping, sound insulation, sliding properties, abrasion resistance, antiblocking properties, and antibacterial properties can be added to the resin raw material.

[0091] The kneading state evaluation device 10 of this embodiment can be used for general purposes to evaluate the kneading state when these various additives are added.

[0092] (Operation and Effect of the Embodiment) As described above, the kneaded state evaluation device 10 of the embodiment is a kneaded state evaluation device that evaluates the kneaded state when a kneaded product is produced by kneading a resin raw material and a filler that imparts predetermined physical properties to the resin raw material in a twin-screw extruder 30 (extrusion molding machine), and includes a temperature distribution selection unit 61 that selects a temperature distribution of the barrel 32 that will obtain a kneaded product with desired physical properties according to the amount of filler to be added, based on physical properties corresponding to the kneaded products kneaded in each of a plurality of different patterns that have been acquired in advance, and a temperature distribution selection unit 62 that selects a temperature distribution of the barrel 32 that will obtain a kneaded product with desired physical properties according to the amount of filler to be added, based on physical properties corresponding to the kneaded products kneaded in each of the different patterns. to the temperature distribution selected by the temperature distribution selection unit 61, a kneading control unit 63 that kneads the resin raw material and the filler in a state in which the temperature distribution of the barrel 32 has been set by the temperature distribution setting unit 62, an AE signal detection unit 64 that detects the signal intensity output by an AE sensor 20 that is installed on the surface of the barrel 32 and detects elastic waves generated inside the twin-screw extruder 30 while the kneading control unit 63 is kneading the resin raw material and the filler, and a kneading state determination unit 65 that determines that appropriate kneading is being performed when the AE signal detection unit 64 detects a predetermined value of signal intensity. Therefore, the kneading state of the raw material can be directly determined in-line (in a state where the extruder is incorporated into a production line).

[0093] In the kneading state evaluation device 10 according to the embodiment, the predetermined value is a value based on the signal intensity output by the AE sensor 20 when the resin raw material and the filler are kneaded in a temperature distribution previously acquired and selected by the temperature distribution selection unit 61. Therefore, by using the previously acquired AE signal measurement data 12c as reference data, the kneading state can be easily evaluated.

[0094] The kneading state evaluation device 10 of the embodiment further includes a kneading state notification unit 66 that notifies the user that the kneading state determination unit 65 has determined that proper kneading is being performed or that proper kneading is not being performed. Therefore, the kneading state of the resin raw material and the filler in the twin-screw extruder 30 can be immediately monitored.

[0095] Although the embodiments of the present invention have been described above, these embodiments are merely examples and are not intended to limit the scope of the invention. This novel embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments are included within the scope and spirit of the invention, and are also included in the inventions described in the claims and their equivalents.

[0096] 10... kneading state evaluation device, 12a... control program, 12b... physical property measurement data, 12c... AE signal measurement data, 15... barrel temperature controller, 16... extruder controller, 17... notification device, 20... AE sensor, 30... twin-screw extruder (extruder), 32... barrel, 36a, 36b... supply port, 39... heater, 42... output shaft, 44... screw, 46... kneading disc, 61... temperature distribution selection unit, 62... temperature distribution setting unit, 63... kneading control unit, 64... AE signal detection unit, 65... kneading state determination unit, 66... ​​kneading state notification unit, D... detection signal, W... AE wave

Claims

1. A mixing state evaluation device for evaluating the mixing state when a resin raw material and a filler that imparts predetermined physical properties to the resin raw material are mixed in an extruder to produce a mixed product, the device comprising: a temperature distribution selection unit that selects a temperature distribution of the barrel of the extruder that will produce a mixed product with desired physical properties according to the amount of filler to be added, based on physical properties corresponding to the mixed products kneaded in each of a plurality of different patterns of temperature distribution of the barrel obtained in advance; a temperature distribution setting unit that sets the temperature distribution of the barrel to the temperature distribution selected by the temperature distribution selection unit; a mixing control unit that kneads the resin raw material and the filler in a state in which the temperature distribution of the barrel has been set by the temperature distribution setting unit; an AE signal detection unit that detects the signal strength output by an AE sensor that detects elastic waves generated inside the extruder, which is installed on the surface of the barrel, while the kneading control unit is kneading the resin raw material and the filler; and a kneading state determination unit that determines that proper mixing is being performed when the AE signal detection unit detects a predetermined value of signal strength. An apparatus for evaluating the kneading state of an extruder comprising:

2. The extruder mixing state evaluation device described in claim 1, wherein the predetermined value is a value based on the signal strength output by the AE sensor when the resin raw material and the filler are mixed using a temperature distribution selected by the temperature distribution selection unit, which has been acquired in advance.

3. The mixing state evaluation device for an extruder according to claim 1 or claim 2, further comprising a mixing state notification unit that notifies the user that the mixing state determination unit has determined that proper mixing is being performed, or that proper mixing is not being performed.

4. A method for evaluating a mixing state when a resin raw material and a filler that imparts predetermined physical properties to the resin raw material are mixed in an extruder to produce a mixed product, the method comprising: a physical property measurement step of setting the temperature distribution of the barrel of the extruder to a plurality of patterns and measuring physical properties corresponding to the mixed product kneaded at each of the set plurality of temperature distributions; a kneading step of kneading the resin raw material and the filler at a desired temperature distribution determined from the distribution of physical properties measured in the physical property measurement step; an AE signal acquisition step of acquiring the signal intensity output by an AE sensor that is installed on the surface of the barrel and detects elastic waves generated inside the extruder during the kneading step; and a kneading state determination step of determining that proper mixing is being performed when the signal intensity acquired in the AE signal acquisition step is a predetermined value.

5. The kneading state evaluation method according to claim 4, wherein the predetermined value is a value based on the signal intensity output by the AE sensor when the resin raw material and the filler are kneaded at the desired temperature distribution acquired in advance.

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