JPH08150655A - Extrusion amount measuring device in extruder - Google Patents

Abstract

PURPOSE: To measure the accurate extrusion amt. in a die head part by measuring a static extrusion amt. and a dynamic extrusion amt. CONSTITUTION: In an extruder 10 wherein the polymeric material charged in a hopper 11 is melted to be extruded to a die head part 15 through a cylinder 12, a static extrusion amt. is calculated from the material flow rate detected by a weighting sensor 20 by an operation part 26. The material temp., the cylinder temp. the number of rotations of a screw, the change quantities of resin pressure in the cylinder and the die head detected by heat sensors 21, 22, a rotation sensor 24 and pressure sensors 23, 25 are set to variables and a dynamic extrusion amt. is calculated on the basis of an auto-regressive exogenous model by an operation part 27 and an actual extrusion amt. is calculated from the static and dynamic extrusion amts. by an operation part 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extruder that melts a polymer material and extrudes it into a die, and more particularly to an extrusion rate measuring device for an extruder that measures the extrusion rate of a resin material.

[0002]

2. Description of the Related Art Conventionally, in this type of extrusion amount measurement, for example, JP-A-3-261539 and JP-A-5-32991.
As described in Japanese Patent Publication No. 6, the average extrusion rate is calculated from the material weight of the hopper, and the target extrusion rate is calculated based on the dimensions (width, thickness) of the created film, the take-up speed and the density of the material. In some cases, the average extrusion rate was adjusted to the target extrusion rate.

In addition, in order to stabilize the extrusion rate, there has been a method in which a gear pump is provided in the die head section and the extrusion rate is calculated backward from the discharge rate.

[0004]

As shown in FIG. 3, the actual extrusion amount F is a steady state which shows a static movement of the normal extrusion amount.

[0005]

[Outside 1]

It is composed of a dynamic extrusion amount ΔF which shows the movement of the extrusion amount, but in the extrusion amount measurement of the above publication, only the static extrusion amount can be calculated, and the dynamic extrusion amount cannot be calculated. There was a problem. Further, in the above extrusion rate measurement, since the material weight on the hopper side is detected, even if the flow rate changes on the hopper side, it takes at least several minutes until the change reaches the die head portion. Due to the existence of such dead time, the extrusion amount measured on the hopper side is not the instantaneous value of the extrusion amount on the die head side at that time, so that there is a problem that the extrusion amount control lacks accuracy. Furthermore, because the size of the created film is detected, it takes a long time to measure the extrusion rate, and it is difficult to measure in a short span, and more material is wasted, which increases the cost of creating the film. There was also a problem.

Further, in the extrusion rate measurement provided with a gear pump, a temperature rising phenomenon often appears in the pump, so that the molten material is pyrolyzed or another mutation phenomenon (for example, in the case of a material containing a foaming agent, a foaming phenomenon occurs). However, there is a problem in that it cannot be commercialized. The present invention has been made in view of the above problems, and an object thereof is to provide an extrusion rate measuring device of an extruder capable of measuring a static extrusion rate and a dynamic extrusion rate and measuring an accurate extrusion rate in a die head. And

[0008]

In order to achieve the above-mentioned object, according to a first aspect of the present invention, in an extruder in which a polymer material charged in a hopper is melted and extruded to a die head through a cylinder, the material is charged into the hopper. A charge amount detecting means including a weighing sensor for detecting the charge amount of the polymer material, a first temperature detecting means including a heat sensor for detecting the temperature of the material, and a heat sensor for detecting the temperature of the cylinder. A first temperature detection means for detecting the rotation speed of a screw provided in the cylinder, a rotation speed detection means for detecting the rotation speed of a screw provided in the cylinder, and a pressure sensor for detecting the pressure of the polymer material in the cylinder. A second pressure detecting means including a pressure detecting means and a pressure sensor for detecting the pressure of the polymer material in the die head, and an average extrusion amount based on the detected charging amount. A minute calculation amount is calculated on the basis of the first calculation means including a calculation unit for outputting, the detected material temperature, the cylinder temperature, the screw rotation speed, and the change amount of the polymer material pressure in the cylinder and the die head. An extruder provided with a second calculation unit including a calculation unit and a third calculation unit including a calculation unit that calculates an extrusion rate of the extruder based on the calculated average extrusion rate and minute time extrusion rate. An extrusion rate measuring device is provided.

According to a second aspect of the present invention, in an extruder in which a polymer material charged in a hopper is melted and extruded through a cylinder to a die head, first temperature detecting means including a heat sensor for detecting the temperature of the material, Second temperature detecting means including a heat sensor for detecting the temperature of the cylinder, rotation speed detecting means including a rotation sensor for detecting the rotation speed of a screw provided in the cylinder, and a polymer material in the cylinder. Based on the detected screw rotation speed, and a first pressure detection means including a pressure sensor for detecting the pressure of No. 1, a second pressure detection means including a pressure sensor for detecting the pressure of the polymer material in the die head, Calculating means for calculating an average extrusion rate by means of a first calculating means, the detected material temperature, cylinder temperature, screw rotation speed, in-cylinder and die head Second calculating means including an arithmetic unit for calculating the minute time extrusion amount based on the change amount of the polymeric material pressure, and the actual extrusion of the extruder based on the calculated average extrusion amount and minute time extrusion amount. And a third calculation unit including a calculation unit that calculates the amount.

In the third aspect, the second calculating means calculates the minute time extrusion rate based on the autoregressive exogenous model using the variation of each event in consideration of the characteristics of the extruder as a variable.

[0011]

[Function] The static extrusion rate is calculated from the detected material input rate, and the dynamic extrusion rate is calculated from the detected changes in material temperature, cylinder temperature, screw rotation speed, and polymer material pressure in the cylinder and die head. Is calculated, and the actual extrusion rate is obtained from the static extrusion rate and the dynamic extrusion rate.

According to a second aspect of the present invention, the static extrusion rate is calculated from the detected screw rotation rate instead of the material input rate, and the detected material temperature, cylinder temperature, screw rotation rate, in-cylinder and in die head. The dynamic extrusion rate is calculated from the change in the pressure of the polymer material, and the actual extrusion rate is calculated from the static extrusion rate and the dynamic extrusion rate. According to the third aspect, the dynamic extrusion rate is estimated by the autoregressive exogenous model with the variables of the material temperature, the cylinder temperature, the screw rotation number, and the pressure of the polymer material in the cylinder and the die head as variables.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an extrusion rate measuring device for an extruder according to the present invention will be described with reference to the drawings of FIGS. The inventors of the present application, in creating the present invention, the temperature of the polymer material in the hopper, for example, the polyethylene material, the temperature of the cylinder, the rotation speed of the screw provided in the cylinder, the resin in the cylinder Pressure (melting polymer material in the cylinder) and resin pressure in the die head provided at the outlet of the cylinder (hereinafter referred to as "extrusion pressure").
It was detected that such events affect the extrusion rate.

Therefore, in the present invention, the static extrusion rate is calculated from the flow rate of the polymer material, and the material temperature,
The dynamic extrusion rate is calculated from the cylinder temperature, the screw rotation speed, the resin pressure in the cylinder and the die head, and the actual extrusion rate is calculated from the static extrusion rate and the dynamic extrusion rate. FIG. 1 is a block diagram showing the configuration of an extrusion rate measuring device according to the present invention. In the figure, a hopper 11 of the extruder 10 is provided with a metering sensor 20 such as a load cell to measure the flow rate of a polymer material, and a heat sensor 21 such as a thermocouple is provided to provide a material.

[0015]

[Outside 2]

1 is connected to the ΔF calculation unit 27,
Data of the measured material temperature Tm is output to the ΔF calculation unit 27. The cylinder 12 has a thermal sensor 22 such as a thermocouple.
Is provided to measure the cylinder temperature, and the pressure sensor 23 is provided to measure the resin pressure in the cylinder 12. Further, a rotation sensor 24 is provided in a screw motor 14 that rotationally drives the screw 13 in the cylinder 12, and the number of rotations of the screw 13 is measured. The heat sensor 22, the pressure sensor 23, and the rotation sensor 24 are connected to the ΔF calculation unit 27, respectively, and measure the measured cylinder temperature Tc,
Each data of the resin pressure Pc and the screw rotation speed N is output to the ΔF calculation unit 27.

In measuring the cylinder temperature, as shown in FIG.
When the screw 13 in the cylinder 12 is formed in a tapered shape whose diameter gradually increases in the resin flow direction, the compression zone of the extruder 10 starts, that is, the screw 13 begins to taper. Then, it was detected by experiment that the temperature change at this position had a great influence on the extrusion rate, because the material began to melt in a full-scale and became a melt. Therefore, in this embodiment, the thermal sensor 22 is arranged at a position where the taper portion of the screw 13 starts.

Further, in measuring the resin pressure in the cylinder 12, when the screw 13 is formed in a tapered shape as shown in FIG. 1, the starting position of the metering zone of the extruder, that is, the taper of the screw 13 is measured. The part is over,
Since the resin flow is stable at the position where the flat part starts, it was detected by experiment that the pressure change at this position has a large effect on the extrusion rate. Therefore, in this embodiment, the pressure sensor 23 is arranged at the position where the taper portion of the screw 13 ends.

Since the cylinder temperature and the resin pressure are affected by the shape of the screw as described above, it is desirable to detect the optimum arrangement position by experiments or the like according to the shape of the screw. Further, a pressure sensor 25 is provided in the die head portion 15 at the outlet of the cylinder 12 to measure the extrusion pressure in the die head portion 15. The pressure sensor 25 is ΔF
It is connected to the calculation unit 27 and outputs the measured data of the extrusion pressure Pd to the ΔF calculation unit 27.

[0020]

[Outside 3]

Flow rate data FH output from the sensor 20
The following formula (1)

[0022]

[Equation 1]

[0023]

[Outside 4]

That is, it is output to the F calculation unit 28 as a static extrusion amount. The ΔF calculation unit 27 includes the thermal sensors 21, 22 and
Five variables output from the pressure sensor 23, the rotation sensor 24, and the pressure sensor 25 (material temperature Tm, cylinder temperature Tc, resin pressure Pc, screw rotation speed N, and extrusion pressure P).
The time series data of d) is taken in, and the autoregressive exogenous (hereinafter referred to as “ARX”) model is calculated using these time series data by the following formula (2).

[0025]

[Equation 2]

[0026]

[Outside 5]

28 can be constituted by a CPU. Next, the parameters a1, b1, c1, d1, e1, and f1 are estimated by the following 5-input 1-output primary system. First, ΔF (i) = a1ΔF (i-1) + b1ΔTc (i-1) + c1ΔTm (i-
1) + d1ΔPc (i-1) + e1ΔPd (i-1) + f1ΔN (i-1) + V
(i)

[0028]

(Equation 3)

## EQU1 ## here,

[0030]

[Equation 4]

Then, the equation (3) becomes

[0032]

(Equation 5)

And the estimated value is

[0034]

(Equation 6)

[0035] The error V is

[0036]

(Equation 7)

When this is multiplied by the transpose V ^T of V,

[0038]

(Equation 8)

It becomes The error can be minimized by minimizing the V ^T V. Therefore, each parameter a
Partial differentiation is performed on 1, b1, c1, d1, e1, and f1. Since the above partial differentiation is the same for each parameter, the case of a1 and f1 is shown here as a representative.

[0040]

[Equation 9]

It becomes Expanding equation (4),

[0042]

[Equation 10]

-(Y-a1z1-b1z2-c1z3-d1z4
^{-E1z5-f1z6) T z1 + (} y-a1z1-b1z2-c1
z3-d1z4-e1z5-f1z6) ^T (-z1) = 0, and therefore the above formula becomes (y-a1z1-b1z2-c1z3-d1z4-e1z5-f1z6) ^T z1 = 0 (6). Similarly, the parameters b1, c1, d1, e1, f1
The partial differential with respect to, (y-a1z1-b1z2- c1z3-d1z4-e1z5-f1z6) T z2 = 0 ... (7) (y-a1z1-b1z2-c1z3-d1z4-e1z5-f1z6) T z3 = 0 ... (8 ) (y-a1z1-b1z2- c1z3-d1z4-e1z5-f1z6) T z4 = 0 ... (9) (y-a1z1-b1z2-c1z3-d1z4-e1z5-f1z6) T z5 = 0 ... (10) (y- a1z1-b1z2-c1z3-d1z4- e1z5-f1z6) T z6 = 0 ... it is (11). Next, when these expressions (6) to (11) are combined,

[0044]

[Equation 11]

It becomes Here, when transposition is performed with [z1 ... z6] = z, the above equation (12) becomes

[0046]

(Equation 12)

It becomes Here, since z and y are experimental data, the parameters a1, b1, c1, d1, e1 and f1 can be calculated. Also, the first-order and higher-order parameters (ai, bi, ci, di, ei, fi, where i> 1) shown in the equation (2) can be calculated by the same method. The estimation of the above parameters is generally known in the ARX model.

[0048]

[Outside 6]

Next, the operation of the extrusion rate measuring device shown in FIG. 1 will be described with reference to the flow chart of FIG. First, A
The parameters and order of the RX model are set, and the sampling time of the static extrusion rate and the sampling time of the dynamic extrusion rate are set (step 101). Since the sampling time of the static extrusion rate is usually longer than the sampling time of the dynamic extrusion rate, it is set to a multiple.

Next, it is judged whether or not the above parameters are reset (step 102). This is because, for example, in the case of measuring the extrusion amount of materials having different materials, the accuracy of extrusion amount measurement becomes higher if parameters are newly set according to the materials. Here, when resetting the above parameters, the process returns to step 101 and is reset.

[0051]

[Outside 7]

The F calculator 27 starts sampling each data and determines whether or not the set sampling time has been reached (step 103). Then, each time the set sampling time is reached, each sensor 20-25

[0053]

[Outside 8]

If the pulling time has not been reached, F
The calculation unit 28 calculates the actual extrusion amount F from the dynamic extrusion amount ΔF input from the ΔF calculation unit 27. In addition, the above-described operation of measuring the extrusion amount is repeatedly performed until, for example, the operator gives an instruction to finish. Therefore, in this embodiment,
Since the extrusion amount at the die head part is calculated from the static extrusion amount which is the average value of the extrusion amount and the dynamic extrusion amount for every minute time, the actual extrusion amount can be accurately measured.

Further, in the present embodiment, since the extrusion amount is measured by using the time series data of a plurality of variables that affect the extrusion amount, the change in the extrusion amount can be measured at any time, and the measurement wastes. You can save time. Further, in this embodiment, since the extrusion amount is obtained using the ARX model, the causal relationship between the past state of each variable (the past state not only one step before but several steps before) and the extrusion amount is shown. Can be detected.

In this embodiment, the static extrusion rate is calculated from the flow rate of the material, but the present invention is not limited to this, and the static extrusion rate can be calculated from the screw rotation speed N, for example. In this case, the expression

[0057]

(Equation 13)

From this, the static extrusion rate can be calculated.

[0059]

As described above, according to the first aspect of the present invention, in the extruder in which the polymer material charged into the hopper is melted and extruded through the cylinder to the die head, the polymer material charged into the hopper is charged. Charge amount detecting means for detecting the amount, first temperature detecting means for detecting the temperature of the material, second temperature detecting means for detecting the temperature of the cylinder, and rotation of a screw provided in the cylinder. A rotation speed detecting means for detecting the number, a first pressure detecting means for detecting the pressure of the polymer material in the cylinder, and a second pressure detecting means for detecting the pressure of the polymer material in the die head. First calculating means for calculating an average extrusion amount based on the detected input amount, and the detected material temperature, cylinder temperature, screw rotation speed, polymer material pressure in the cylinder and die head It is provided with a second calculating means for calculating a minute time extrusion amount based on the change amount, and a third calculating means for calculating an extrusion amount of the extruder based on the calculated average extrusion amount and minute time extrusion amount. Therefore, the static extrusion rate and the dynamic extrusion rate can be measured to measure the accurate extrusion rate at the die head.

According to a second aspect of the present invention, in an extruder in which a polymer material charged in a hopper is melted and extruded through a cylinder to a die head, first temperature detecting means for detecting the temperature of the material, and temperature of the cylinder. Temperature detecting means for detecting the rotation speed, rotation speed detecting means for detecting the rotation speed of the screw provided in the cylinder, and first pressure detecting means for detecting the pressure of the polymer material in the cylinder. Second pressure detecting means for detecting the pressure of the polymer material in the die head, first calculating means for calculating an average extrusion rate based on the detected screw rotation speed, and the detected material temperature , Second temperature calculation means for calculating the minute time extrusion amount based on the amount of change in the polymer temperature in the cylinder, the screw rotation speed, the cylinder, and the die head, and the calculated average extrusion. And a third calculation means for calculating the actual extrusion rate of the extruder based on the minute time extrusion rate,
Since the static extrusion rate is calculated from the detected screw rotation number instead of the material input rate, the accurate extrusion rate in the die head can be measured in this case as well.

In the third aspect, the second calculating means calculates the minute time extrusion rate based on the autoregressive exogenous model using the variation of each event considering the characteristics of the extruder as a variable. Can be measured at any time.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an extrusion rate measuring device according to the present invention.

FIG. 2 is a flowchart for explaining the operation of the extrusion rate measuring device shown in FIG.

FIG. 3 is a diagram showing changes over time in the actual extrusion rate.

[Explanation of symbols]

 10 Extruder 11 Hopper 12 Cylinder 13 Screw 14 Screw Motor 15 Die Head Part 20 Weighing Sensor 21,22 Thermal Sensor 23,25 Pressure Sensor 24 Rotation Sensor 26-28 Calculation Unit

Claims (3)

[Claims] 1. An extruder for melting a polymeric material loaded into a hopper and pushing it out to a die head through a cylinder, and a loading amount detecting means for detecting a loading amount of the polymeric material loaded into the hopper, First temperature detecting means for detecting the temperature of the material; second temperature detecting means for detecting the temperature of the cylinder; rotational speed detecting means for detecting the rotational speed of a screw provided in the cylinder; First pressure detecting means for detecting the pressure of the polymeric material in the cylinder, second pressure detecting means for detecting the pressure of the polymeric material in the die head, and average extrusion based on the detected charging amount. A first calculation means for calculating the amount, and a minute time extrusion based on the detected material temperature, cylinder temperature, screw rotation speed, and the amount of change in the polymer material pressure in the cylinder and die head. Extrusion, comprising: a second calculating means for calculating the actual extrusion rate of the extruder on the basis of the calculated average extrusion rate and minute time extrusion rate. Extruder output measuring device. 2. An extruder in which a polymer material charged in a hopper is melted and extruded through a cylinder to a die head, and a first temperature detecting means for detecting a temperature of the material and a temperature of the cylinder are detected. Second temperature detection means, rotation speed detection means for detecting the rotation speed of a screw provided in the cylinder, first pressure detection means for detecting the pressure of the polymer material in the cylinder, and the die head Second pressure detecting means for detecting the pressure of the polymer material in the inside, first calculating means for calculating an average extrusion rate based on the detected screw rotation speed, the detected material temperature, cylinder temperature A second calculation means for calculating a minute time extrusion amount based on the amount of change in the screw rotation speed, the pressure of the polymer material in the cylinder and the die head, and the calculated average extrusion amount and the minute amount. Extrusion rate measuring apparatus of an extruder, characterized in that a third calculation means for calculating the actual extrusion rate of the extruder based on the time the extrusion rate. 3. The second calculating means calculates the minute time extrusion rate based on an autoregressive exogenous model, with the variation of each event considering the characteristics of the extruder as a variable. Item 3. An extrusion rate measuring device for an extruder according to Item 1 or 2.