JP2022102286A - Shrinkage estimation device, shrinkage estimation method, program, storage medium, and method of manufacturing extrusion molded products - Google Patents

Abstract

To estimate a shrinkage rate of an extrusion molded product during extrusion.SOLUTION: A shrinkage rate estimation device comprises a shrinkage rate estimation unit 305 configured to estimate a shrinkage rate of an extrusion molded product based on a torque current of a motor provided in an extruder and extrusion conditions of the extruder.SELECTED DRAWING: Figure 10

Description

The present invention relates to a shrinkage rate estimation technique for estimating the shrinkage rate of an extruded product.

Japanese Unexamined Patent Publication No. 2020-44695 (Patent Document 1) describes a technique for detecting a torque generated in a rotating screw of a rubber extruder and estimating the viscosity of a rubber material based on the detected torque data. Have been described.

Japanese Unexamined Patent Publication No. 2020-44695

For example, a cable, which is a typical extruded product, has a structure in which a conductor is coated with a resin in order to ensure insulation, and the resin covering the conductor is formed by, for example, an extrusion molding technique. After that, an annealing treatment is performed on the resin formed by the extrusion molding technique, and it is known that the cable shrinks after the annealing treatment. For example, if the resin shrinks in the longitudinal direction of the cable, the outer diameter of the cable may increase and the outer diameter may fluctuate, or the lead wire (core wire) may be exposed from the end of the cable. For this reason, it is desired to reduce the shrinkage rate of the cable.

Regarding this point, at present, the shrinkage rate (dimensions after annealing treatment) of an extruded product containing a resin extruded from an extruder as a constituent material cannot be grasped at the time of extrusion. For this reason, defects occur after the annealing treatment, which leads to a decrease in manufacturing yield and an increase in lead time. Therefore, from the viewpoint of improving the productivity of extruded products, a technique capable of estimating the shrinkage rate at the time of extrusion is desired.

The shrinkage rate estimation device in one embodiment includes a shrinkage rate estimation unit that estimates the shrinkage rate of the extruded product based on the torque current of the motor provided in the extruder and the extrusion conditions of the extruder.

The shrinkage rate estimation method in one embodiment includes a shrinkage rate estimation step for estimating the shrinkage rate of the extruded product based on the torque current of the motor provided in the extruder and the extrusion conditions of the extruder.

This shrinkage rate estimation method can be realized by causing a computer to execute a process of estimating the shrinkage rate of the extruded product by using a program. For example, this program includes a shrinkage rate estimation process that estimates the shrinkage rate of an extruded product based on the torque current of a motor provided in the extruder and the extrusion conditions of the extruder. The program in one embodiment can be recorded, for example, on a computer-readable recording medium.

The method for manufacturing an extruded product according to an embodiment includes a shrinkage rate monitoring step for monitoring the shrinkage rate of the extruded product in real time based on the torque current of the motor provided in the extruder and the extrusion conditions of the extruder. Further, the method for manufacturing the extruded product according to the embodiment includes a shrinkage rate estimation step for estimating the shrinkage rate of the extruded product in real time based on the torque current of the motor provided in the extruder and the extrusion conditions of the extruder. It includes an extrusion condition adjusting step of adjusting the extrusion conditions based on the shrinkage ratio, and a molding step of extruding the resin under the adjusted extrusion conditions.

According to one embodiment, the shrinkage rate of the extruded product can be estimated at the time of extrusion. Further, this can improve the productivity of the extruded product.

It is a schematic diagram explaining the extrusion molding process which covers the outer periphery of a conducting wire with resin. It is a schematic diagram which shows the state of covering a conducting wire with resin extruded from a die. It is a graph which shows the measurement result (experimental data) which measured the temperature of a resin. It is a graph which shows the time dependence of the viscosity calculated based on experimental data, and the time dependence of the torque current output from an extruder together. It is a figure explaining the validity that there is a correlation between "torque current" and shrinkage rate of an extruded article. It is a figure which shows the procedure which performs the formulation of the correlation between "torque current" and shrinkage rate. It is a schematic diagram explaining "strain rate". It is a figure which plotted the measured data. It is a figure which shows an example of the hardware composition of the shrinkage rate estimation apparatus. It is a functional block diagram which shows the functional composition of the shrinkage rate estimation apparatus. It is a figure explaining the machine learning which determines a temperature coefficient and a viscosity index. It is a figure explaining the machine learning which determines the constant of (formula VIII). It is a flowchart explaining the basic operation of the shrinkage rate estimation apparatus. It is a flowchart explaining the basic operation of the shrinkage rate estimation apparatus. It is a flowchart explaining the application operation of the shrinkage rate estimation apparatus. It is a flowchart explaining a part of the manufacturing process of an extruded product. It is a flowchart explaining a part of the manufacturing process of an extruded product.

In all the drawings for explaining the embodiments, the same members are designated by the same reference numerals in principle, and the repeated description thereof will be omitted. In addition, in order to make the drawing easier to understand, hatching may be added even if it is a plan view.

<Cable manufacturing method>
In the present embodiment, in the method for manufacturing a cable in which the conductor is coated with resin, a step of coating the outer periphery of the conductor with resin by using an extrusion molding technique will be described.

FIG. 1 is a schematic diagram illustrating an extrusion molding process in which the outer periphery of a conducting wire is coated with a resin.

In FIG. 1, when the raw material pellets 10 which are the raw materials of the coating material are put into the extruder 11 and kneaded, the molten resin is extruded from the die 13 via the crosshead 12. The extruded resin is coated on the surface of the conductor 14 that moves along the traveling line. Then, the resin coated on the surface of the conducting wire 14 is air-cooled immediately after being extruded from the die 13, and then water-cooled in the water tank 15. In this way, the resin extruded from the die 13 is solidified in the cooling process by air cooling and water cooling. Here, the conducting wire 14 is composed of a stranded copper wire or the like. The raw material pellet (plastic material) 10 is made of a thermoplastic polyurethane resin or the like.

After that, an annealing treatment is performed on the extrusion-molded product containing the resin formed by the extrusion molding technique as a constituent material, but it is known that the extrusion-molded product shrinks after the annealing treatment. Since the shrinkage of the extruded product adversely affects the quality of the extruded product, it is desirable to reduce the shrinkage rate of the extruded product.

Regarding this point, for example, if the shrinkage rate (dimensions after annealing treatment) of the extruded product can be grasped in real time during extrusion molding of the extruded product, it is considered that the manufacturing yield can be improved and the lead time can be reduced. .. That is, from the viewpoint of improving the productivity of extruded products, a technique capable of estimating the shrinkage rate in real time is desired.

<Basic idea in the embodiment>
The basic idea in the present embodiment is not to directly estimate the shrinkage rate itself but to focus on the physical quantity that correlates with the shrinkage rate in order to estimate the shrinkage rate of the extruded product in real time. The idea is to indirectly estimate the contraction rate by estimating. In particular, if a physical quantity that can be grasped in real time as a physical quantity that correlates with the shrinkage rate can be found, it is considered that the shrinkage rate can be estimated in real time based on this physical quantity.

This basic idea has, for example, the following advantages.

For example, in order to estimate the shrinkage rate itself with high accuracy, it is necessary to consider both the extrusion conditions and the material properties of the resin. However, with the shrinkage rate estimation technique that formulates the shrinkage rate itself, it is not only difficult to formulate the shrinkage rate itself in consideration of both the extrusion conditions and the material properties of the resin, but also the measurement of "crystallinity" is possible. It also includes the required parameters. As a result, it is difficult to introduce the technique for formulating the shrinkage rate itself in real time in the manufacturing process of the extruded product.

On the other hand, according to the basic idea, it is not necessary to formulate the shrinkage rate itself, and if a physical quantity that correlates with the shrinkage rate can be formulated, the shrinkage rate can be indirectly estimated from the formulated physical quantity. can. At this time, if it is easy to consider both the extrusion conditions and the material properties of the resin in the formulation of the physical quantity, and if the formulation can be performed without including the parameter that requires measurement of "crystallinity", the shrinkage rate can be determined. In addition to being able to estimate with high accuracy, it can also be introduced in real time in the manufacturing process of extruded products. In other words, if a physical quantity that can be grasped in real time as a physical quantity that correlates with the shrinkage rate and that can be formulated in consideration of extrusion conditions and material properties is found, the shrinkage rate can be estimated with high accuracy. It can also be introduced in real time in the manufacturing process of extruded products.

Therefore, the present inventor has focused on a physical quantity called "torque current" as a result of diligent studies to find such a physical quantity, and therefore, "torque current" will be described below.

<"Torque current">
An extruder is used in the extrusion process. In the extruder, the raw material pellets, which are the raw materials for the coating material, are kneaded with a rotating screw. Then, by extruding the kneaded molten resin from the outlet of the die, the outer circumference of the conducting wire is covered with the resin. Here, the screw is rotated by a motor provided in the extruder. At this time, the load current flowing through the motor that rotates the screw is the "torque current". The present inventor has newly found that this "torque current" is a physical quantity that correlates with the shrinkage rate of the extruded product. In particular, the "torque current" is the current flowing through the motor that rotates the screw that kneads the resin, and the extruder is configured to detect abnormal rotation of the screw by constantly monitoring this "torque current". Has been done. From this, the "torque current" is a physical quantity that can be grasped in real time in the extrusion molding process. Therefore, if the "torque current" correlates with the shrinkage rate of the extruded product, it is possible to estimate the shrinkage rate of the extruded product in real time from the "torque current".

Here, it is not clear that there is a correlation between the "torque current" and the shrinkage of the extruded product. Therefore, in the following, first, it will be qualitatively explained that there is a correlation between the “torque current” and the shrinkage rate of the extruded product.

<Qualitative understanding of correlation>
<< Explanation of "pulling stress">>
The "pulling stress" plays an important role in explaining the existence of a correlation between the "torque current" and the shrinkage of the extruded product. Therefore, "pulling stress" will be described.

FIG. 2 is a schematic view showing how the conductor is covered with the resin extruded from the die.

In FIG. 2, the molten resin 20 extruded from the outlet of the die 13 is covered with the surface of the conducting wire 14 moving at a constant linear velocity. Then, the molten resin 20 coated on the surface of the conducting wire 14 is cooled in the water tank 15 and crystallized. At this time, as shown in FIG. 2, the molten resin 20 extruded from the outlet of the die 13 is pulled by the conducting wire 14 moving along the traveling line. As a result, the stress applied diagonally to the molten resin 20 from the time it is extruded from the outlet of the die 13 to the time it is covered with the conductor 14 is the “pull-down stress σ”.

The present inventor speculates that this "pulling stress" correlates with the shrinkage of the extruded product. In this regard, the reason why the present inventor has come to speculate that there is a correlation between the “pulling stress” and the shrinkage rate will be described. The present inventor speculates that there is a correlation between the "pulling stress" and the shrinkage rate, as a result of understanding the shrinkage mechanism shown below.

Therefore, the contraction mechanism grasped by the present inventor will be described.

In the extrusion molding technique, a molten resin extruded from a die is stretched to produce a product (extruded product) having a desired size. At this time, due to the "pulling stress" applied to the extruded molten resin, the polymer chains of the polymer, which is a constituent material of the molten resin, are elongated, and the molten resin is water-cooled in a state where the polymer chains are elongated. After that, when the resin is exposed to a high temperature again by the annealing treatment, the "pulling stress" applied to the resin is eliminated, and as a result, the resin shrinks. The resin shrinks due to the above mechanism. Therefore, according to this mechanism, it can be seen that the "pulling stress" contributes to the shrinkage of the extruded product containing the resin as a constituent material. In consideration of this, the present inventor has come to speculate that there is a correlation between the "pulling stress" and the shrinkage rate.

<< Relationship between "pulling stress" and viscosity >>
Next, it will be explained that the "pulling stress" correlates with the viscosity. According to the mechanism described above, the polymer chain of the polymer, which is a constituent material of the molten resin, is elongated due to the “pulling stress” applied to the extruded molten resin. Therefore, it can be considered that the "pulling stress" is affected by the material properties of the resin. In particular, since the "pulling stress" is considered to be greatly affected by the fluidity of the resin, it is presumed that the "pulling stress" has a correlation with the viscosity representing the fluidity of the resin. For example, it is understood that as the viscosity increases qualitatively, the "pulling stress" also increases, so it is reasonable to speculate that there is a correlation between the "pulling stress" and the viscosity.

<< Relationship between viscosity and "torque current">>
Subsequently, it will be explained that the viscosity correlates with the "torque current". For example, the kneading of the resin is performed by rotating the screw with a motor. At this time, if the viscosity of the resin is high, the energy for rotating the screw to knead the resin is large. This means that a large load is applied to the motor that rotates the screw, which increases the "torque current" for rotating the motor. On the other hand, when the viscosity of the resin is small, the load applied to the motor for kneading the resin is small. This means that the "torque current" becomes smaller. Therefore, it can be considered reasonable that there is a correlation between viscosity and "torque current".

In the following, the experimental results showing that there is a correlation between viscosity and "torque current" will be described. First, the viscosity is calculated. Specifically, since the viscosity can be expressed by (Formula I) described later, the viscosity can be calculated based on this (Formula I). For example, based on the resin used in the experiment and the extrusion conditions of the extruder, the “viscosity constant η ₀ ” included in (Formula I) is 9/11 × 10 ¹¹ (Pa · ^sn ), and the “temperature coefficient α”. Is 8.42 × 10 ² (1 / ° C.), and the “viscosity index n” is 0.225.

Here, in the case of the viscosity of the resin extruded from the extruder to the outside and stretched, the “strain rate” is used as (dγ / dt) included in (Formula I). On the other hand, in the case of the viscosity of the resin kneaded inside the extruder, the "shear rate" is used for (dγ / dt) included in (Formula I).

Then, assuming that the "shear velocity" is constant inside the extruder and regarded as a constant, the viscosity η can be calculated from the temperature T of the resin based on (Formula I).

Therefore, the temperature of the resin extruded from the extruder is measured. Specifically, a thermocouple was inserted into a hole made in the tip of the extruder to measure the temperature of the resin. FIG. 3 is a graph showing measurement results (experimental data) of measuring the temperature of the resin.

Subsequently, the viscosity is calculated by substituting the experimental data shown in FIG. 3 into (Formula I). FIG. 4 is a graph showing the time dependence of the viscosity calculated based on the experimental data (indicated in black) and the time dependence of the torque current output from the extruder (indicated in gray).

As shown in FIG. 4, focusing on the peak position surrounded by a circle, it can be read that there is a correlation between the calculated viscosity value and the torque current value. From the above experimental results, it is considered appropriate that there is a correlation between the viscosity and the "torque current".

The above can be summarized in FIG. FIG. 5 is a diagram illustrating the validity of the existence of a correlation between the “torque current” and the shrinkage rate of the extruded product. In FIG. 5, from the above-mentioned qualitative explanation, it is presumed that there is a correlation (first correlation) between the “pulling stress” and the shrinkage rate. It is presumed that there is a correlation (second correlation) between the "pulling stress" and the viscosity, and there is also a correlation (third correlation) between the viscosity and the "torque current". Is presumed to exist. Therefore, when these first correlations, second correlations, and third correlations are comprehensively considered, there may be a correlation between the "torque current" and the shrinkage rate of the extruded product. Guessed. That is, considering the first correlation, the second correlation, and the third correlation, it can be inferred that the "torque current" and the shrinkage rate have a correlation with each other through the viscosity and the "pulling stress". Can be done. In this way, it is qualitatively understood that there is a correlation between the "torque current" and the shrinkage of the extruded product.

<Formulation of correlation>
Furthermore, the present inventor is trying to formulate the correlation one step further from the qualitative understanding of the "torque current" and the shrinkage rate and the correlation of the extruded product, and this point will be described.

FIG. 6 is a diagram showing a procedure for formulating the correlation between the “torque current” and the shrinkage rate.

As shown in FIG. 6, first, as a first step, the correlation between the viscosity and the "torque current" is formulated. Then, as the second step, the correlation between the "pulling stress" and the "torque current" is formulated, and then as the third step, the correlation between the shrinkage rate and the "torque current" is formulated.

In the following, it will be described that the correlation between the shrinkage rate and the “torque current” can be finally formulated according to the procedure shown in FIG.

<< First stage: Formulation of the correlation between viscosity and "torque current">>
Generally, the viscosity is expressed by the following formula (I).

here,
t: Time η: Viscosity η ₀ : Viscosity constant α: Temperature coefficient T: Resin temperature dγ / dt: Strain rate n: Viscosity index

<< Explanation of strain rate >>>
Here, the "strain rate" included in (Formula I) will be described.

FIG. 7 is a schematic diagram illustrating the “strain rate”.

In FIG. 7, the cross-sectional area of the outlet of the die 13 is indicated by “S _d ”. The molten resin 20 is extruded from the outlet of the die 13. At this time, the average flow velocity of the molten resin 20 extruded from the outlet of the die 13 is “v _d ”. The molten resin 20 extruded from the outlet of the die 13 at an average flow velocity “v _d ” is stretched by the addition of a linear velocity “v _f ”. Here, “S _f ” shown in FIG. 7 is a cross-sectional area of a molded product made of a conducting wire coated with the molten resin 20. Further, "L" shown in FIG. 7 is a distance from the outlet of the die 13 to the water tank 15.

In such a configuration, the "strain rate" is represented by the following (Formula II).

here,
dγ / dt: strain rate v _d : average flow velocity of molten resin at the outlet of the die v _f : linear velocity L: distance from the outlet of the die to the water tank

That is, the "strain rate" is defined as a physical quantity obtained by dividing the difference between the average flow velocity "v _d " and the linear velocity "v _f " by the distance "L" from the outlet of the die 13 to the water tank 15. The "strain rate" defined in this way becomes zero if, for example, the average flow velocity "v _d " and the linear velocity "v _f " are equal. That is, the fact that the average flow velocity “v _d ” and the linear velocity “v _f ” are equal is a physical quantity related to the strain of the molten resin 20 because it can be qualitatively considered that the molten resin 20 is not strained. It is understandable that the "strain rate" becomes zero. Further, since it can be considered that the strain applied to the molten resin increases as the difference between the average flow velocity “v _d ” and the linear velocity “v _f ” increases, the “strain rate” is expressed by (Formula II). That is reasonable.

<<< Assumption of linearity >>>
Next, in formulating the correlation between the viscosity represented by the above-mentioned (Formula I) and the "torque current", the linearity between the viscosity and the "torque current" is assumed. This assumption is valid, for example, because it agrees with the qualitative understanding that the "torque current" increases as the viscosity increases. Based on this assumption, the viscosity is expressed by the following (Formula III).

here,
t: time η: viscosity a: constant τ: torque current b: constant

According to the study of the present inventor, when the "torque current" is changed, the average flow velocity (v _d ) of the molten resin at the outlet of the die, the linear velocity (v _f ), and the distance from the outlet of the die to the water tank (L). ), The temperature (T), the temperature coefficient (α), and the viscosity index (n) of the resin are almost constant, while the viscosity constant (η ₀ ) of the resin mainly changes. ..

Based on this finding, the linearity of the viscosity and the "torque current" expressed by (Equation III) is almost equivalent to expressing the viscosity constant (η ₀ ) by the following (Equation IV).

here,
t: time η ₀ : viscosity constant a ₀ : constant τ: torque current b ₀ : constant

As described above, the correlation between the viscosity and the "torque current" can be formulated.

<< Second stage: Formulation of the correlation between "pulling stress" and "torque current">>
Next, the formulation of the correlation between the "pulling stress" and the "torque current" will be described.

The correlation between "pulling stress" and viscosity is expressed by the following (formula V).

here,
t: Time σ: Withdrawal stress η: Viscosity dγ / dt: Strain rate η ₀ : Viscosity constant α: Temperature coefficient T: Resin temperature n: Viscosity index

For example, the formulation of "pulling stress σ" (formula V) includes "viscosity η", which represents the relationship of "pulling stress σ" ∝ "viscosity η". In this way, the "pulling stress" is formulated (Formula V) in consideration of the material property of resin viscosity and the extrusion conditions including temperature and strain rate, and when the viscosity increases qualitatively, the "pulling stress" is obtained. It can be said that the formulation by (Equation V) is in line with the qualitative understanding.

The formulation of "pulling stress" (Formula V) has the following usefulness.

(1) (Formula V) is a relational expression that takes into consideration both the material property of the viscosity of the resin and the extrusion conditions of the temperature and strain rate of the resin. This makes it possible to estimate the "pulling stress" with higher accuracy than the formulation that considers only the material properties and the formulation that considers only the extrusion conditions. This means that if the "pulling stress" and the "shrinkage rate" of the extruded product have a high correlation, the "shrinkage rate" can be estimated with high accuracy in consideration of both material properties and extrusion conditions. means. From this, the significance of the formulation by (Formula V) is great.

(2) Next, the formula (formula V) for formulating the "pulling stress" does not include the "crystallinity". This is because, as shown in FIG. 2, the resin extruded from the die 13 (for example, the temperature of the resin is 180 ° C. to 200 ° C.) is the molten resin 20, and the molten resin 20 is cooled in the water tank 15 and crystallized. To become. Therefore, before reaching the water tank 15, the resin is in a molten state and it is not necessary to consider the “crystallinity”. That is, the "pulling stress" has great significance in that the "crystallinity" is not included as a parameter. That is, since the “pull-down stress” is focused on and the “pull-down stress” is formulated (formula V), the parameter “crystallinity” that needs to be measured is not included, so that the extruded product is manufactured. It can be said that it has great significance in that it can be easily introduced in real time in the process.

Next, by substituting the relationship of (Formula IV) with respect to the viscosity constant (η ₀ ) included in (Formula V) representing "pulling stress", the following (Formula VI) is obtained.

here,
t: Time σ: Withdrawal stress a ₀ : Constant τ: Torque current b ₀ : Constant α: Temperature coefficient T: Resin temperature dγ / dt: Strain rate n: Viscosity index

As described above, the correlation between "pulling stress" and "torque current" can be formulated.

<< Third stage: Formulation of the correlation between shrinkage rate and "torque current">>
Next, the formulation of the correlation between the shrinkage rate and the "torque current" will be described.

As mentioned above, the shrinkage rate is presumed to correlate with the "pull stress". Therefore, the present inventor proposes to assume linearity in the correlation between the shrinkage rate and the "pulling stress". For example, according to the shrinkage mechanism, the polymer chain of the polymer, which is a constituent material of the molten resin, is elongated by the “pulling stress”. The degree of this elongation is considered to increase as the "pulling stress" increases. Considering that when the resin is exposed to a high temperature by the annealing treatment, the "pulling stress" applied to the resin is eliminated and the resin shrinks, the shrinkage rate increases as the degree of elongation increases. It is understood that it will grow. In other words, it is considered that the larger the "pulling stress" is, the larger the shrinkage rate of the extruded product containing the resin as a constituent material. Therefore, it is not possible to assume linearity between the "pulling stress" and the shrinkage rate of the extruded product. It makes sense.

Therefore, assuming this linearity, the correlation between the "pulling stress" and the shrinkage rate is expressed by the following (formula VII).

here,
t: time ε: shrinkage rate A: constant σ: withdrawal stress C: constant

Then, by substituting the "pulling stress" represented by (Formula VI) into (Formula VII), the following (Formula VIII) is obtained.

here,
t: Time ε: Shrinkage rate A ₀ = Aa ₀ : Constant τ: Withdrawal stress B ₀ = Ab ₀ : Constant α: Temperature coefficient T: Resin temperature dγ / dt: Strain rate n: Viscosity constant C: Constant

As described above, the correlation between the shrinkage rate and the "torque current" can be formulated. According to the formula VIII thus formulated, if the constant A ₀ , the constant B ₀ , the constant C, the temperature coefficient α and the viscosity constant n are known, the temperature (T) and the strain rate (dγ) of the resin are known. The shrinkage factor (ε) of the extruded product can be estimated based on the extrusion condition consisting of / dt) and the “torque current”.

<Correlation verification results>
In the following, the verification results supporting the inventor's insight that the shrinkage rate of the extruded product and the "torque current" have a correlation are described. That is, the verification results supporting the existence of a high correlation between the shrinkage rate and the "torque current" will be described.

In order to verify the correlation between the shrinkage rate and the "torque current", for example, an extrusion experiment is performed using an extrusion molding system having the configuration shown in FIG. Specifically, in the extrusion experiment, a thermoplastic polyurethane resin is used, and the temperature and strain rate of the resin are adopted as the extrusion conditions.

Specifically, an extruded product (cable) with an outer diameter of 1.5 mm is attached to an extruder equipped with a full flight screw with a screw outer diameter of 40 mm, and a die with a hole diameter of 2.25 mm is used. A string-shaped sample made of the material was produced at a linear speed of 20 m / min. At this time, the temperature of the crosshead and the die (corresponding to the temperature of the resin) was changed to 185 ° C., 190 ° C., and 195 ° C., and the "torque current" at the time of extrusion was recorded every second with a data logger. As a result, it is possible to obtain data of a string-shaped sample in which the viscosity is changed by changing the temperature of the resin. The contraction rate was measured using the string-shaped sample thus obtained.

Specifically, a string-shaped sample was taken every 600 seconds at the time of extrusion and cut into about 500 mm. Then, the length of the cut string-shaped sample after being annealed at 130 ° C. for 3 hours is measured, and the shrinkage ratio is measured by dividing the length after the annealing treatment by the initial length. did. As described above, it is possible to obtain actual measurement data showing the relationship between the shrinkage rate and the "torque current".

FIG. 8 is a graph plotting the measured data.

In FIG. 8, the horizontal axis represents the “torque current” (A), while the vertical axis represents the shrinkage rate (%). The ◯ mark shown in FIG. 8 is the data of the resin temperature of 185 ° C., the diamond-shaped mark is the data of the resin temperature of 190 ° C., and the cross mark is the data of the resin temperature of 195 ° C.

As shown in FIG. 8, the correlation coefficient (R) between the “torque current” and the shrinkage rate is “0.89”, and considering that the closer the correlation coefficient is to 1, the higher the correlation is, “ It can be seen that there is a high correlation between "torque current" and shrinkage. In particular, since it can be seen that the measured data has a linear relationship generally shown by a broken line, it can be seen that the formulation of the correlation between the shrinkage rate and the "torque current" by (Equation VIII) is appropriate. ..

From the above-mentioned experimental results, it is confirmed that there is a high correlation between "torque current" and shrinkage rate, and there is a high correlation between "torque current" and shrinkage rate. It has been confirmed that the inventor's guess that this is true is correct. Therefore, the technical idea of estimating the shrinkage of an extruded product based on the "torque current" formulated in (Formula VIII) is that it considers both material properties and extrusion conditions, and that it is extruded. It turns out that it is very useful in that it can be introduced in real time in the manufacturing process of the product.

Taking, for example, an insulating resin that covers a conducting wire as an extruded product as an example, the fact that the shrinkage rate of the insulating resin can be estimated in real time means that the shrinkage rate of the insulating resin extruded from the extruder in the longitudinal direction is sequentially grasped. It means that you can do it.

<Structure of shrinkage rate estimation device>
In the following, a shrinkage rate estimation device that embodies the above-mentioned technical idea will be described.

<< Hardware configuration >>
First, the hardware configuration of the shrinkage rate estimation device in the present embodiment will be described.

FIG. 9 is a diagram showing an example of the hardware configuration of the shrinkage rate estimation device 100 according to the present embodiment. The configuration shown in FIG. 9 is merely an example of the hardware configuration of the shrinkage rate estimation device 100, and the hardware configuration of the shrinkage rate estimation device 100 is not limited to the configuration shown in FIG. Other configurations may be used.

In FIG. 9, the shrinkage rate estimation device 100 includes a CPU (Central Processing Unit) 101 that executes a program. The CPU 101 is electrically connected to, for example, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, and a hard disk device 112 via a bus 113, and controls these hardware devices. It is configured as follows.

The CPU 101 is also connected to an input device and an output device via the bus 113. Examples of the input device include a keyboard 105, a mouse 106, a communication board 107, a scanner 111, and the like. On the other hand, examples of the output device include a display 104, a communication board 107, a printer 110, and the like. Further, the CPU 101 may be connected to, for example, a removable disk device 108 or a CD / DVD-ROM device 109.

The shrinkage rate estimation device 100 may be connected to, for example, a network. For example, when the shrinkage rate estimation device 100 is connected to another external device via a network, the communication board 107 constituting a part of the shrinkage rate estimation device 100 may be a LAN (local area network) or a WAN (wide area network). It is connected to the network) or the Internet.

The RAM 103 is an example of a volatile memory, and the recording medium of the ROM 102, the removable disk device 108, the CD / DVD-ROM device 109, and the hard disk device 112 is an example of the non-volatile memory. The storage device of the shrinkage rate estimation device 100 is configured by these volatile memories and non-volatile memories.

The hard disk device 112 stores, for example, an operating system (OS) 201, a program group 202, and a file group 203. The program included in the program group 202 is executed by the CPU 101 while using the operating system 201. Further, in the RAM 103, at least a part of the program of the operating system 201 or the application program to be executed by the CPU 101 is temporarily stored, and various data necessary for processing by the CPU 101 are stored.

The BIOS 102 (Basic Input Output System) program is stored in the ROM 102, and the boot program is stored in the hard disk device 112. When the shrinkage rate estimation device 100 is started, the BIOS program stored in the ROM 102 and the boot program stored in the hard disk device 112 are executed, and the operating system 201 is started by the BIOS program and the boot program.

The program group 202 stores a program that realizes the function of the shrinkage rate estimation device 100, and this program is read and executed by the CPU 101. Further, in the file group 203, information, data, signal values, variable values and parameters indicating the result of processing by the CPU 101 are stored as each item of the file.

The file is recorded on a recording medium such as a hard disk device 112 or a memory. Information, data, signal values, variable values and parameters recorded in a recording medium such as a hard disk device 112 or a memory are read into a main memory or a cache memory by the CPU 101, and are extracted, searched, referenced, compared, calculated, processed, and processed. It is used for the operation of the CPU 101 represented by editing, output, printing, and display. For example, during the operation of the CPU 101 described above, information, data, signal values, variable values and parameters are temporarily stored in the main memory, registers, cache memory, buffer memory and the like.

The function of the shrinkage rate estimation device 100 may be realized by the firmware stored in the ROM 102, or only the software, only the hardware represented by the element, the device, the board, and the wiring, and the software and the hardware. It may be realized in combination, and further in combination with firmware. The firmware and software are recorded as a program on a recording medium typified by a hard disk device 112, a removable disk, a CD-ROM, a DVD-ROM, or the like. The program is read and executed by the CPU 101. That is, the program causes the computer to function as the shrinkage rate estimation device 100.

As described above, the shrinkage rate estimation device 100 includes a CPU 101 as a processing device, a hard disk device 112 and a memory as a storage device, a keyboard 105 as an input device, a mouse 106, a communication board 107, a display 104 as an output device, and a printer 110. , A computer including a communication board 107. The function of the shrinkage rate estimation device 100 is realized by using a processing device, a storage device, an input device, and an output device.

<< Functional block configuration >>
Next, the functional block configuration of the shrinkage rate estimation device 100 will be described.

FIG. 10 is a functional block diagram showing a functional configuration of the shrinkage rate estimation device.

In FIG. 10, the shrinkage rate estimation device 100 according to the present embodiment has a first known data group input unit 301, a second known data group input unit 302, a first constant determination unit 303, and a second constant determination unit 304. It has a shrinkage rate estimation unit 305, a determination unit 306, a conformity condition search unit 307, an output unit 308, and a data storage unit 309.

The first known data group input unit 301 is configured to input, for example, the first known data group. Here, the "first known data group" is a data group in which the combination of the temperature and strain rate of the resin and the viscosity are associated with each other, and is defined as a data group in which the temperature, strain rate and viscosity of the resin are known. Will be done. These "first known data groups" are input to the first known data group input unit 301 and then stored in the data storage unit 309.

The second known data group input unit 302 is configured to input, for example, the second known data group. Here, the "second known data group" is a data group in which the combination of the torque current and the extrusion conditions and the shrinkage rate of the extruded product are associated with each other, and the torque current, the extrusion conditions and the shrinkage rate of the extruded product are associated with each other. Is defined as a known set of data. Specifically, in the present embodiment, since the extrusion condition is composed of a combination of the temperature of the resin and the strain rate, the “second known data group” is the torque current, the temperature of the resin, and the strain rate. It is a data group in which the combination and the shrinkage rate of the extruded product are related, and is defined as a data group in which the torque current, the temperature of the resin, the strain rate, and the shrinkage rate of the extruded product are known. These "second known data groups" are input to the second known data group input unit 302 and then stored in the data storage unit 309.

Next, the first constant determination unit 303 is based on the first known data group stored in the data storage unit 309 and (formula I), and the "temperature coefficient α" and the "viscosity index" included in (formula I). It is configured to determine "n". Specifically, as shown in FIG. 11, the first constant determination unit 303 uses, for example, a neural network in which the first known data group is used as training data, the input is the temperature and strain rate of the resin, and the output is the viscosity. It is configured to determine the temperature coefficient and viscosity index by training. At this time, for the strain rate, for example, using (Formula II), the average flow velocity (v _d ) and linear velocity (v _f ) of the molten resin at the outlet of the die and the distance from the outlet of the die to the water tank (L). ) Can be obtained. The first constant determination unit 303 is not only configured to determine the temperature coefficient and the viscosity index by using the above-mentioned machine learning, but also, for example, by the minimum square method with respect to the first known data group. It may be configured to determine the temperature coefficient and viscosity index by applying a representative statistical analysis technique. The temperature coefficient and the viscosity index determined in this way are stored in the data storage unit 309.

Subsequently, the second constant determination unit 304 substitutes the second known data group stored in the data storage unit 309, and the temperature coefficient and viscosity index determined by the first constant determination unit 303 (Formula VIII). Based on this, it is configured to determine the constant A ₀ , the constant B ₀ , and the constant C contained in (Formula VIII). Specifically, as shown in FIG. 12, for example, the second constant determination unit 304 uses the second known data group as teacher data and inputs the extrusion conditions (resin temperature and strain rate) and "torque current". It is configured to determine the constant A ₀ , the constant B ₀ , and the constant C by learning a neural network whose output is the shrinkage ratio of the extruded product. At this time, for the strain rate, for example, using (Formula II), the average flow velocity (v _d ) and linear velocity (v _f ) of the molten resin at the outlet of the die and the distance from the outlet of the die to the water tank (L). ) Is required.

The second constant determination unit 304 is not only configured to determine the constant A ₀ , the constant B ₀ , and the constant C by using the machine learning described above, but also for, for example, the second known data group. It may be configured to determine the constant A ₀ , the constant B ₀ and the constant C by applying a statistical analysis technique represented by the least square method. The constant A ₀ , the constant B ₀ , and the constant C determined in this way are stored in the data storage unit 309.

In the above, among the five constants included in (Formula VIII), the temperature coefficient and the viscosity index are determined by the first constant determination unit 303 based on the first known data group, and the constant A ₀ , the constant B ₀ and the constant C are determined. Is described by the second constant determination unit 304 based on the second known data group.

However, the configuration for determining the five constants included in (Formula VIII) is not limited to this, and can be realized by the configuration shown below. That is, a configuration is also conceivable in which the second constant determination unit 304 determines all of the five constants included in (Equation VIII) based on the second known data group. In this case, it is possible to obtain the advantage that it is not necessary to measure the viscosity itself included in the first known data group with a rheometer or the like. Here, when determining five constants by this configuration, it is desirable to use machine learning that is superior to the fitting by the least squares method in fitting a nonlinear function from the viewpoint of improving the fitting accuracy.

Next, the shrinkage rate estimation unit 305 is configured to estimate the shrinkage rate of the extruded product based on the "torque current" of the motor provided in the extruder and the extrusion conditions of the extruder. Specifically, the shrinkage rate estimation unit 305 substitutes the temperature coefficient and the viscosity index determined by the first constant determination unit 303, and the constants A ₀ , the constant B ₀ , and the constant C determined by the second constant determination unit. Based on the above (Formula VIII), the shrinkage ratio of the extruded product is estimated from the extrusion conditions consisting of temperature and strain rate and the "torque current".

Subsequently, the determination unit 306 is configured to determine whether or not the contraction rate estimated by the contraction rate estimation unit 305 is equal to or less than a preset “threshold value”.

The conformity condition search unit 307 is included in (Formula VIII) when the determination unit 306 determines that the contraction rate estimated by the contraction rate estimation unit 305 is not equal to or less than a preset “threshold value”. Change the extrusion conditions (resin temperature and strain rate) to re-estimate the shrinkage of the extruded product, and search for extrusion conditions (conformity conditions) where the re-estimated shrinkage is less than or equal to the "threshold value". It is configured.

The output unit 308 is configured to output, for example, the shrinkage rate estimated by the shrinkage rate estimation unit 305 and the extrusion conditions searched by the matching condition search unit 307.

As described above, the shrinkage rate estimation device 100 according to the present embodiment is configured.

<Operation of shrinkage rate estimation device (shrinkage rate estimation method)>
Subsequently, the operation of the shrinkage rate estimation device 100 in the present embodiment will be described.

<< Basic operation >>
13 and 14 are flowcharts illustrating the basic operation of the shrinkage rate estimation device.

In FIG. 13, first, when the first known data group is input to the first known data input unit 301 (S101), the input first known data group is stored in the data storage unit 309.

Next, the first constant determination unit 303 determines the temperature coefficient and the viscosity index related to the material properties (viscosity) included in (Formula I) based on the first known data group stored in the data storage unit 309. (S102).

On the other hand, when the second known data group is input to the second known data group input unit 302 (S103), the input second known data group is stored in the data storage unit 309. Next, the second constant determination unit 304 substitutes the second known data group stored in the data storage unit 309, and the temperature coefficient and viscosity index determined by the first constant determination unit 303 (Formula VIII). Based on this, the constant A ₀ , the constant B ₀ , and the constant C included in (Formula VIII) are determined (S104). In this way, the relational expression between the "torque current" and the shrinkage rate can be obtained.

In FIG. 14, the shrinkage rate estimation unit 305 has a temperature coefficient and a viscosity index determined by the first constant determination unit 303 when the extrusion conditions (resin temperature and strain rate) and “torque current” are input (S201). The shrinkage rate of the extruded product is estimated based on the constant A ₀ , the constant B ₀ , and the constant C determined by the second constant determination unit 304 (Formula VIII) (S202). Then, the shrinkage rate estimated by the shrinkage rate estimation unit 305 is output from the output unit 308. In this way, the basic operation of the shrinkage rate estimation device 100 is carried out. As a result, according to the shrinkage rate estimation device 100, the shrinkage rate can be estimated in real time based on the "torque current".

<< Applied operation >>
Further, in the shrinkage rate estimation device 100, in addition to the above-mentioned basic operation, the following applied operation can be performed. FIG. 15 is a flowchart illustrating the application operation of the shrinkage rate estimation device. In FIG. 15, when the shrinkage rate of the extruded product is estimated by carrying out the above-mentioned basic operation (S301), then the determination unit 306 presets the shrinkage rate estimated by the shrinkage rate estimation unit 305. It is determined whether or not it is equal to or less than the set "threshold value" (S302). When the shrinkage rate estimated by the shrinkage rate estimation unit 305 is equal to or less than the “threshold value”, the output unit 308 outputs that the shrinkage rate is equal to or less than the “threshold value” (S305). On the other hand, when the shrinkage rate estimated by the shrinkage rate estimation unit 305 is not less than or equal to the “threshold value”, the matching condition search unit 307 changes the extrusion conditions (resin temperature and strain rate) included in (Formula VIII). Then, the shrinkage rate of the extruded product is re-estimated, and the extrusion condition (conformity condition) in which the re-estimated shrinkage rate is equal to or less than the “threshold value” is searched for (S303). Then, the extrusion conditions searched by the conformity condition search unit 307 are output from the output unit 308 (S304). In this way, the applied operation in the shrinkage rate estimation device 100 is carried out. As a result, according to the shrinkage rate estimation device 100, even if the shrinkage rate estimated by the shrinkage rate estimation unit 305 does not satisfy the predetermined condition, the extrusion conditions for the shrinkage rate to satisfy the predetermined condition are presented. can.

By operating the shrinkage rate estimation device 100 as described above, the shrinkage rate estimation method according to the present embodiment is realized.

<Modification example>
When the contraction rate estimation device 100 performs not only the basic operation but also the applied operation, the contraction rate estimation unit 305 needs to be configured to estimate the contraction rate based on (Formula VIII). This is because (Formula VIII) includes "torque current" and extrusion conditions (resin temperature and strain rate) as variables for estimating the shrinkage rate, so the shrinkage rate should be estimated by changing the extrusion conditions. Is possible.

Here, for example, it is conceivable to fix the extrusion conditions of the extruder and perform only the operation of estimating the shrinkage rate of the extruded product under the fixed extrusion conditions. That is, it is conceivable that only the basic operation is performed in the shrinkage rate estimation device 100. In this case, the shrinkage rate estimation unit 305 can be configured to estimate the shrinkage rate based on a relational expression that simplifies (Formula VIII). This is because, when the extrusion conditions are fixed, the term (e ^−αT | dγ / dt | ⁿ ) becomes a constant term. This relational expression is expressed by the following (formula IX).

here,
t: Time ε: Shrinkage rate A ₁ : Constant τ: Torque current B ₁ : Constant

In this case, the first known data group and the first constant determination unit become unnecessary. Further, as the second known data group, it is sufficient to acquire the data group in which the "torque current" changes under the condition that the extrusion conditions are fixed, and the data acquisition becomes easy. Then, the second constant determination unit 304 can be configured to determine the constant A ₁ and the constant B ₁ by applying the least squares method to the second known data group, for example. As described above, according to this modification, the shrinkage rate of the extruded product can be estimated from the "torque current" while simplifying the configuration of the shrinkage rate estimation device 100.

<Shrinkage rate estimation program>
The shrinkage rate estimation method carried out by the shrinkage rate estimation device 100 described above can be realized by a shrinkage rate estimation program that causes a computer to execute a shrinkage rate estimation process.

For example, in the shrinkage rate estimation device 100 composed of a computer shown in FIG. 9, the shrinkage rate estimation program according to the present embodiment can be introduced as one of the program group 202 stored in the hard disk device 112. Then, by causing the computer which is the shrinkage rate estimation device 100 to execute this shrinkage rate estimation program, the shrinkage rate estimation method in the present embodiment can be realized.

A shrinkage rate estimation program that causes a computer to perform each process for creating data related to the shrinkage rate estimation process can be recorded and distributed on a computer-readable recording medium. The recording medium includes, for example, a magnetic storage medium typified by a hard disk or a flexible disk, an optical storage medium typified by a CD-ROM or a DVD-ROM, a hardware device typified by a non-volatile memory such as a ROM or EEPROM, and the like. Is included.

<Effect in the embodiment>
According to the technical idea in the present embodiment, instead of directly estimating the shrinkage rate of the extruded product, focusing on the "torque current" newly found to have a correlation with the shrinkage rate. The shrinkage rate is indirectly estimated based on this "torque current". This not only makes it possible to estimate the shrinkage rate with high accuracy by easily considering both material properties and extrusion conditions, but also it is not necessary to consider the parameter that requires measurement called "crystallization degree", but it is grasped in real time. Since it uses a possible "torque current", it has great technical significance in that it can provide a shrinkage rate estimation technique that can be introduced in real time in the manufacturing process of an extruded product.

<Manufacturing method of extruded products>
For example, until now, there was no shrinkage rate estimation technique that could be introduced in real time in the manufacturing process of extruded products. Therefore, the shrinkage rate should be reduced by adjusting the extrusion conditions based on the experience of the workers. Was being done. In this regard, according to the technical idea in the present embodiment, it is possible to introduce an objectively accurate shrinkage rate estimation technique into the manufacturing process (manufacturing line) of the extruded product without relying on the experience of the worker. can. As a result, according to the present embodiment, it is possible to reduce the amount of waste of the resin material and the extruded product (for example, the cable) and improve the production efficiency. That is, the technical idea in the present embodiment makes it possible to introduce the shrinkage rate estimation technique into the production line of the extruded product in real time, and as a result, obtains a remarkable effect that the production yield of the extruded product can be improved. be able to. Therefore, in the following, a manufacturing process of an extruded product using the technical idea in the present embodiment will be described.

<< Specific Example 1 >>
For example, in Specific Example 1, a method of manufacturing an extruded product including a shrinkage rate monitoring step of monitoring the shrinkage rate of the extruded product in real time based on the torque current of a motor provided in the extruder will be described.

FIG. 16 is a flowchart illustrating a part of the manufacturing process of the extruded product.

In FIG. 16, first, the extrusion conditions in the extruder are initially set (S401), the resin is kneaded under the initially set extrusion conditions, and the molten resin is extruded from the outlet of the die. The kneading of the resin at this time is performed by rotating the screw with a motor provided in the extruder.

Here, in order to grasp the rotation abnormality of the screw, the "torque current" for driving the motor is constantly monitored. In Specific Example 1, the shrinkage rate of the extruded product is estimated in real time based on this "torque current", and whether or not the estimated shrinkage rate of the extruded product is within a predetermined threshold value. (S402) Then, if the estimated shrinkage of the extruded product is within the threshold range, it is determined that the shrinkage is "OK" (S403), and the extruder is operated. Continue to monitor the shrinkage of the extruded product. On the other hand, if the estimated shrinkage of the extruded product is out of the threshold range, it is determined that the shrinkage is "NG" (S403), and the operation of the extruder is stopped (S404). .. This makes it possible to prevent the production of defective products.

<< Specific Example 2 >>
In Specific Example 2, extrusion conditions are adjusted based on the result of real-time estimation of the shrinkage rate of the extruded product based on the torque current of the motor provided in the extruder, and the extruded product is manufactured under the adjusted extrusion conditions. A method for manufacturing a molded product will be described.

FIG. 17 is a flowchart illustrating a part of the manufacturing process of the extruded product.

In FIG. 17, first, the extrusion conditions are initially set (S501). Next, the shrinkage rate estimation technique in the present embodiment is used. Specifically, for example, five constants consisting of "temperature coefficient α", "viscosity index n", "constant A ₀ ", "constant B ₀ " and "constant C" were determined (formula VIII). Then, by substituting the “torque current” monitored in real time and the preset extrusion conditions into this (formula VIII), the shrinkage rate of the extruded product is estimated (S502). At this time, the above-mentioned basic operation and applied operation are carried out.

As a result, if the estimated shrinkage is less than or equal to the "threshold", the default extrusion conditions are maintained. On the other hand, if the estimated shrinkage rate is not less than or equal to the threshold value, the condition is changed to the conforming condition (extrusion condition) presented in the applied operation (S503).

Then, the resin is extruded under the maintained extrusion conditions or the changed extrusion conditions (S504). Then, the resin is annealed (S505), and after a predetermined period has elapsed (1 to 2 days later), the shrinkage rate is measured (S506). At this time, when the shrinkage ratio is not more than a predetermined value (OK) (S507), an extruded product as a non-defective product is manufactured. On the other hand, when the shrinkage rate is not less than or equal to a predetermined value (NG), the constant included in (Formula VIII) is redetermined in consideration of this NG data (S508). For example, the constant included in (Formula VIII) is redetermined by retraining the neural network by adding the above-mentioned NG data. In this way, the method for manufacturing an extruded product according to the present embodiment is realized.

According to the method for manufacturing an extruded product according to the present embodiment, the shrinkage rate estimation technique is introduced into the production line to estimate the shrinkage rate of the extruded product in real time, so that the manufacturing yield of the extruded product is improved. Can be made to. Furthermore, even if the estimated shrinkage rate is "OK", if the finally measured shrinkage rate is "NG", the constant included in (Formula VIII) should be redetermined based on this NG data. Therefore, the estimation accuracy of the shrinkage rate can be improved.

Although the invention made by the present inventor has been specifically described above based on the embodiment thereof, the present invention is not limited to the embodiment and can be variously modified without departing from the gist thereof. Needless to say.

For example, the "torque current" of a motor provided in an extruder differs depending on the type of motor and the shape of the screw, but if a value is determined under the standard extrusion conditions (molding conditions), the relative value of the extruded product will be used. It is possible to grasp the increase or decrease in the shrinkage rate. From this, it is possible to apply the technical idea in the above embodiment to any kind of extruder as long as the reference conditions of the extruder are known. However, in the full flight screw, since the structure of the screw is simple, it is easy to apply the technical idea in the embodiment.

The technical idea in the above embodiment is applicable to a wide variety of resins including plastics and rubbers, and is not limited to, for example, thermoplastic polyurethane resins. Further, the technical idea in the above embodiment can be applied to a wide range of extrusion modes regardless of tube extrusion, wire extrusion, or die shape. Further, the extruded product (product) manufactured by the method for manufacturing an extruded product to which the technical idea in the above embodiment is applied may be in any shape or type such as a sheet shape, an irregular shape, or a cable (electric wire).

10 Raw material pellets 11 Extruder 12 Crosshead 13 Die 14 Conductor 15 Water tank 20 Molten resin 100 Shrinkage rate estimation device 101 CPU
102 ROM
103 RAM
104 Display 105 Keyboard 106 Mouse 107 Communication board 108 Removable disk device 109 CD / DVD-ROM device 110 Printer 111 Scanner 112 Hard disk device 201 Operating system 202 Program group 203 File group 301 First known data group Input unit 302 Second known data group Input unit 303 1st constant determination unit 304 2nd constant determination unit 305 Shrinkage rate estimation unit 306 Judgment unit 307 Conformity condition search unit 308 Output unit 309 Data storage unit

Claims (15)

A shrinkage rate estimation device that estimates the shrinkage rate of an extruded product containing a resin extruded from an extruder as a constituent material.
The shrinkage rate estimation device is a shrinkage rate estimation device including a shrinkage rate estimation unit that estimates the shrinkage rate of the extruded product based on the torque current of the motor provided in the extruder and the extrusion conditions of the extruder. In the shrinkage rate estimation device according to claim 1,
The shrinkage rate estimation unit is a shrinkage rate estimation device that estimates the shrinkage rate of the extruded product based on the following mathematical formula 1.

here,
t: Time ε (t): Shrinkage rate A ₀ : Constant τ (t): Torque current B ₀ : Constant α: Temperature coefficient T: Resin temperature dγ / dt: Strain rate n: Viscosity index C: Constant In the shrinkage rate estimation device according to claim 2,
The strain rate is a shrinkage rate estimation device represented by the mathematical formula 2 shown below.

here,
dγ / dt: strain rate v _d : average flow velocity of molten resin at the outlet of the die v _f : linear velocity L: distance from the outlet of the die to the water tank In the shrinkage rate estimation device according to claim 3,
The temperature coefficient and the viscosity index included in the formula 1 are included in the formula 3 shown below, which is a shrinkage rate estimation device.

here,
t: Time η: Viscosity η ₀ : Viscosity constant α: Temperature coefficient T: Resin temperature dγ / dt: Strain rate n: Viscosity index In the shrinkage rate estimation device according to claim 4,
The shrinkage rate estimation device is
A first known data group input unit for inputting a first known data group in which the combination of the temperature and the strain rate and the viscosity are associated with each other.
A first constant determination unit that determines the temperature coefficient of the viscosity and the viscosity index based on the first known data group input from the first known data group input unit and the mathematical formula 3.
A second known data group input unit for inputting a second known data group in which a combination of the torque current, the temperature, and the strain rate and the shrinkage rate of the extruded product are associated with each other.
The above is based on the second known data group input from the second known data group input unit, the formula 1 in which the temperature coefficient of the viscosity and the viscosity index determined by the first constant determination unit are substituted. A second constant determination unit for determining the constant A ₀ , the constant B ₀ , and the constant C included in the equation 1 and the like.
Have,
The shrinkage rate estimation unit includes the temperature coefficient and the viscosity index determined by the first constant determination unit, and the constant A ₀ , the constant B ₀ , and the constant C determined by the second constant determination unit. A shrinkage coefficient estimation device that estimates the shrinkage rate of the extruded product from the extrusion condition consisting of the temperature and the strain rate and the torque current based on the formula 1 in which the above is substituted. In the shrinkage rate estimation device according to claim 5,
The first constant determination unit uses the first known data group as teacher data, and trains a neural network in which the input is the temperature and the strain rate and the output is the viscosity, thereby causing the temperature coefficient and the viscosity. A shrinkage estimator that determines the exponent. In the shrinkage rate estimation device according to claim 5,
The second constant determination unit is a shrinkage rate estimation device that determines the constant A ₀ , the constant B ₀ , and the constant C by applying the least squares method to the second known data group. In the shrinkage rate estimation device according to claim 5,
The second constant determination unit learns a neural network in which the second known data group is used as teacher data, the input is the extrusion condition and the torque current, and the output is the shrinkage ratio of the extruded product. , The contraction rate estimation device for determining the constant A ₀ , the constant B ₀ , and the constant C. A shrinkage rate estimation device that estimates the shrinkage rate of an extruded product containing a resin extruded from an extruder as a constituent material.
The shrinkage rate estimation device is a shrinkage rate estimation device including a shrinkage rate estimation unit that estimates the shrinkage rate of the extruded product based on the torque current of a motor provided in the extruder. In the shrinkage rate estimation device according to claim 9,
The shrinkage rate estimation unit is a shrinkage rate estimation device that estimates the shrinkage rate of the extruded product based on the mathematical formula 4 shown below.

here,
t: Time ε: Shrinkage rate A ₁ : Constant τ: Torque current B ₁ : Constant It is a shrinkage rate estimation method that estimates the shrinkage rate of an extruded product containing a resin extruded from an extruder as a constituent material.
The shrinkage rate estimation method is a shrinkage rate estimation method including a shrinkage rate estimation step for estimating the shrinkage rate of the extruded product based on the torque current of a motor provided in the extruder and the extrusion conditions of the extruder. A program that causes a computer to execute a process of estimating the shrinkage rate of an extruded product containing a resin extruded from an extruder as a constituent material.
The program includes a shrinkage rate estimation process for estimating the shrinkage rate of the extruded product based on the torque current of the motor provided in the extruder and the extrusion conditions of the extruder. A computer-readable recording medium on which the program according to claim 12 is recorded. A method for manufacturing an extruded product containing a resin extruded from an extruder as a constituent material.
The method for manufacturing an extruded product is a method for manufacturing an extruded product, comprising a shrinkage rate monitoring step for monitoring the shrinkage rate of the extruded product in real time based on the torque current of a motor provided in the extruder. A method for manufacturing an extruded product containing a resin extruded from an extruder as a constituent material.
A shrinkage rate estimation step that estimates the shrinkage rate of the extruded product in real time based on the torque current of the motor provided in the extruder and the extrusion conditions of the extruder.
An extrusion condition adjusting step of adjusting the extrusion conditions based on the estimated shrinkage rate, and
A molding step of extruding the resin under the adjusted extrusion conditions, and
A method for manufacturing an extruded product.

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