JPS59167242A - Controlling method of temperature of resin in plastic molding machine - Google Patents

Abstract

PURPOSE:To attain the increase in the amount of resin to be discharged, the reduction of scorching, and saving of energy by a method in which measured temperature of a cylinder is added by a correcting temperature from at least three or more parameters including room temperature and the revolving number of screw to estimate the temperature of molten resin, and on the basis of the deviation of the temperature from a desired temperature, the temperature of the resin is controlled. CONSTITUTION:Thermocouples C1-C4 to measure the temperatures of each zone in a cylinder 2, a tachometer generator 9 to detect the revolving number of a screw 8, and a temperature-sensing resistor 10 to measure the ambient temperature of an extruder 1 are provided. A correcting temperature calculated from at least three or more parameters including room temperature and screw revolving number among the parameters such as room temperature, screw revolving number, screw shape, set temperature, the kinds of resins, etc., to vary the temperatures of resin is added to the measured temperature of the cylinder 2 to estimate the temperature of the resin. The deviation between the estimated temperature and a desired temperature is obtained, and on the basis of the deviation, the temperature of the resin is controlled.

Description

Detailed Description of the Invention This invention provides resin temperature control in a plastic molding machine to control the resin temperature in the molding machine to the optimum temperature for molding, in addition to molding plastic using a plastic molding machine such as extrusion rate. Regarding the method.

In the case of extruded acid type plastics, etc., controlling the humidity and temperature of each zone in the cylinder of the extruder to a temperature suitable for the feed fat for the housing increases the extrusion amount, reduces scorch, reduces energy costs, Furthermore, it has a very important meaning from the point of view of improving electrical layer properties as an insulating material for electrofusion/cables, etc.

Conventional extrusion-like resin temperature control involves drilling a plurality of temperature-measuring holes 3 in the cylinder 2 of an extruder 1 that do not penetrate the cylinder 2, as shown in FIG. Insert temperature measuring element 4... into each temperature measuring zone of cylinder 2,
Measure the temperature of CI,c,103,c, and
These temperatures are input to the temperature controller 5..., and the heating device 6, such as a band heater or embedded heater, provided on the outside of the cylinder 2, and the cooling device 7, such as a cooling blower.
This is done by controlling the temperature, lil, and 11-section shuchu resistance.

However, it has become clear that this method has the following problems. That is, in the above control method, the temperature measuring element 4
There is a difference between the measured temperature by The temperature difference (△T,) or each temperature measurement zone (C2r
03 r 04), and ■ Also, due to the change in the rotation speed of the screw 80 of the extruder 1 when the resin is poured into the extruder 1, the actual resin temperature and cylinder 2 as shown in FIG.
The temperature difference between the temperature and the temperature is further increased by T2 minutes.

Therefore, it was found that due to these influences, the temperature of the molten resin in the cylinder 2 was heated to a temperature higher than the desired temperature, and energy was wasted.

(In addition, 02, C3+ 0 in Figures 2 and 3
4 represents the temperature measurement position of the cylinder 2, which corresponds to each temperature measurement zone of C2+C3+04 shown in each temperature controller 5... in FIG. ) Furthermore, according to recent studies, the temperature of the bath melted fat in the cylinder 2 is determined by not only the electromagnetic and screw rotation speeds as mentioned above, but also the set temperature of the extruder 1, the shape and structure of the screw, and the temperature of the extruder 1. It has become clear that it is influenced by the four different grades of resin (including differences in grades of the same resin). For example, when extruding polyethylene resin, the set temperature of the heating leg 5 is set to 120°C, and the temperature measured by the thermometer 4 is set to 1.
Even at 20°C, the actual bath melting temperature IJTh recommendation is 130°C.
The temperature has reached ~140℃.

In the past, it was impossible to accurately determine the temperature waves of the resin in the sun's bath by simply measuring the temperature using the temperature measurement hole 3.

Therefore, as an improvement to this type of Jubei Banshiki, the special
A resin temperature control device for an extruder has been proposed as shown in Japanese Patent No. 121042. This temperature control device is installed at a position outside the inner wall surface of the cylinder of the extruder, and includes a first temperature detector which is output as a temperature detection signal at position d, and a temperature sensor located outside the outside wall surface of the cylinder of the extruder. A second temperature sensor is installed at a position in the sea or inside, and outputs a detection signal as a 'fJjhlli detection signal at the team position, and a target temperature signal at the position where the droplet IE detector is installed is set as the output. The temperature setting device of the heat l and F? a second temperature setter whose set output is a target temperature signal at a position where the second temperature detector is installed; a temperature signal detected by the first temperature detector;
A first ratio soft operation gain that performs a ratio soft calculation on the first target temperature signal from the first temperature setting device, the temperature signal detected by the second temperature detector written in MiJ, and the first ratio a second comparison device that performs a soft calculation to compare the correction signal of the second target temperature signal from the setting device to the second temperature based on the soft calculation device output signal;
The present invention includes an output device that selectively adjusts the amount of heat of the heating/cooling device according to the output signal of the second ratio controller.

Then, when the temperature near the inner capsule surface of the cylinder is lower than the set temperature of the first temperature setting device, the first ratio softener sends an output signal to stop, and this signal is sent from the setting device to the temperature of @2. The target temperature signal is added to the target temperature signal and sent to the second ratio softener, and the heating/cooling device is heated based on the output signal from the second ratio softener, increasing the temperature near the inner bottom surface of the cylinder. It will be done. Conversely, if the temperature near the inner six surfaces of the cylinder is higher than the target temperature, the heating/cooling device is operated for cooling. Similarly, if the temperature near the outer surface of the cylinder is lower than the target temperature of the second temperature setter, which is corrected by the output signal of the tenth ratio, the second ratio w is heated via the second temperature setter. The cooling device is heated. Conversely, if the temperature near the outer surface of the cylinder is higher than the revised target temperature, the heating/cooling device is operated for cooling. However, even with this conventional resin temperature control device, the temperature of the cylinder is simply controlled by measuring the temperature of the cylinder wall, so as mentioned above, there is a difference between the set temperature and the actual resin temperature. Since there is a large temperature difference depending on the parameters, even such a temperature control device has the disadvantage that the actual resin temperature cannot be accurately controlled.

Therefore, in order to overcome the shortcomings of the two conventional resin temperature control methods mentioned above, the inventors of the present invention directly contact the molten resin with the temperature-sensing part of the temperature element on the inner surface of the cylinder or the outer surface of the screw. We have proposed a method of directly measuring the temperature of the molten resin in the cylinder by setting it up as a thermometer, but in these methods, the temperature sensing part of the thermometer is constantly in direct contact with the resin in the bath molten state, so it is difficult to trace the temperature. The temperature sensing part of the temperature sensor is prone to wear and resin retention, and the temperature sensor must be replaced frequently, which poses problems in the long-term continuous operation of the extruder. The publication also revealed that cylinders with through-holes have problems such as crank formation around the through-holes due to long-term use.

Therefore, a temperature control method that includes means for correcting fluctuations in resin temperature due to molding machine screw rotation speed and room temperature has been developed.
It has been proposed in Japanese Patent Application No. 191906/1986 in four volumes of misfires.

This method measures the temperature of the cylinder, and corrects the temperature value calculated from the room temperature, the rotary speed of the screw (9), and other variables that reduce the temperature of the melted resin in the cylinder. The wave is predicted, the deviation between the predicted resin temperature and the desired resin temperature is found, and the temperature of the molten la resin in the cylinder is controlled based on this deviation. It was impossible to control 'jf8 fat temperature with waves.

This invention was made in view of the above circumstances, and it is possible to accurately predict the temperature of the bath melted resin in the cylinder, to maintain the resin temperature at the desired temperature, to increase the amount of resin discharged, and to reduce scorch. The purpose of the present invention is to provide a resin temperature control method for a plastic molding machine that saves energy, does not wear out the temperature measuring element, and can operate an extruder etc. continuously during the -bC period. Measure the temperature of the cylinder, and adjust this temperature to room temperature, screw rotation speed,
Screw shape, temperature setting, resin value classification Kasa's general melting resin temperature I
Change the lever? The temperature of the melted resin in the cylinder is predicted by adding the corrected temperature from at least three parameters including the temperature, room temperature, and rotational speed of the screw, and the deviation between this predicted temperature and the desired resin temperature is calculated. is determined, and the temperature of the bath f8i resin in the cylinder is controlled based on this deviation.

Hereinafter, this invention will be explained in detail with reference to Figure Wj.

Figure 4 shows an example of the configuration of an extruder whose temperature is controlled by applying the temperature control method of the present invention, and is the same as Figure 1.
Parts are given the same reference numerals and the 7th line is omitted. Each zone of the cylinder 2 of the extruder 1 is provided with a heat which determines the temperature of each zone of the cylinder 2. c) As shown in FIG. 5, the thermocouple C is inserted into the hot water 3, which is drilled from the inner surface of the cylinder 2, leaving a thickness of about 10 mF. In addition,
The depth of the temperature measurement hole 3... should be selected by considering the extruder 1, extrusion conditions, etc. In addition, at the base of the screw 80,
A rotary generator 9 is installed to measure the rotational speed of the screw 80, and a resistance temperature detector 10 is provided to measure the room temperature around the extruder 1. The outputs from the thermocouple C9 rotary generator 9 and the temperature suppressor 10 are sent to a processing system suitable for the temperature control method of the present invention shown in FIG. That is, thermocouple C! 2,
03, C! 4 and the room temperature resistance thermometer 10 are input to the linearizer 11... and linearized.

Then, this linearized signal is sent to the scanner 12, which sequentially sends it to the A/D converter 14 based on a scan command from the microprocessor 13.
The data is input to the microprocessor 13, digitized, and further input to the microprocessor 13. Further, the signal from the screw rotation generator 9 is manually input to another A/D converter 14, digitized, and input to the microprocessor 13.

At the same time, the microprocessor 13 is also input with information regarding parameters for varying the temperature of the melted resin, such as the shape of the screw 8, the type of resin (which also accounts for differences in grade within the same resin), and the set temperature. . In addition, the above-mentioned linearizer 11, t: U A/D converter 1
4 becomes unnecessary when each detection means is incorporated in each detection means.

Then, the microprocessor 13 calculates the room temperature and the screw rotation speed based on the relationship between the room temperature and ΔT1 and the relationship between the screw rotation speed and ΔT shown in FIGS. 2 and 3 which are stored in advance. , △T1 and △T at each temperature measurement position
, and from the above parameters, a corrected temperature determined by these parameters determined by a program stored in advance is calculated. clearly,
At the above △TI+△T2 and correction temperature, thermocouple C2°C
! The temperatures corresponding to the respective side temperatures of the cylinder 2 measured in step 3.04 are added, and the resin temperature inside the cylinder 2 is predicted for each temperature measurement zone.

Further, these predicted resin temperatures are compared with the desired resin temperature I and the separately stored desired resin temperature, the deviation thereof is determined, and the set temperature of the temperature controller 5 is calculated based on this deviation. This set temperature is sent from the microprocessor 13 to the ski scanner 15 on the output side, and is sequentially sent to the D/A converters 16 . . . based on a scan command from the microprocessor 1. Except for this, the set temperature of each zone is set corresponding to that zone.
The temperature is input to the temperature controller 5, converted into an analog signal, and sent to the temperature controller 5 provided corresponding to each zone. In addition, this set temperature can be set using a thermocouple ('2 + 03 r 04
The signals are sent to the temperature controllers 5, .

Temperature controller 5... has a separate thermocouple 02.
+08 A signal from +04 is input, and this signal is compared with the above-mentioned set temperature to operate the heating device 6 such as a band heater or embedded heater or the cooling device 7 such as a cooling prower to cool down each thermoelectric element. Make the measured temperature k at pair C match the set temperature. In this way, the temperature of the bath melted resin in the cylinder 2P'3 comes to match the desired resin temperature.

According to such a temperature control method, parameters such as the rotation speed of the screw 8, room temperature, the shape of the screw 8, the set temperature, and the type of resin that vary the resin temperature of the bath melted resin in the cylinder 2 are changed. Also, the amount of variation in resin temperature that occurs due to this change is determined by the microprocessor 13,
This vibration proof is always taken into consideration, and the temperature is carefully set.
The temperature controller 5 controls the resin temperature, and the 1JA degree of resin in the cylinder 2 quickly matches the desired resin temperature and is maintained at an appropriate temperature.

In the above example, the temperature control method described in the present invention is applied only to the thermocouple C2+CB+"4 corresponding to the temperature measurement zone on the extruder 1, but This temperature control method may be similarly applied to OI.

However, in normal extrusion operations, temperature control in three zones, C2+C3+C4, is sufficient. In addition, heating of cylinder 2,
The cooling means is not limited to the above example, and for example, silicone
/ Heating and cooling means using a fluid heat medium such as oil may be used.

Hereinafter, a specific explanation will be given by showing examples.

〔Example〕

Screw diameter 50 kokum, L/D=20, cylinder thickness N-2
51nz, heater capacity c, 2.2kW, C! 2
+OsrC40,7kW, PTD Extrusion mode equipped with a temperature controller was used to extrude low density polyethylene containing a crosslinking agent by applying the temperature control method of the present invention.

(1) Place the set temperature thermocouple at a distance of 10 mN from the inner surface of the cylinder, fix C1 to 120°C, and issue commands from the microprocessor to C2+ ”, + C4, and so on. by.

(2) Desired resin temperature for each zone E C,... Not specified C2...126°G (3) Resin temperature prediction formula % formula % y: Cylinder temperature measured by thermocouple C △T,: Correction temperature according to room temperature △T2: Correction temperature according to screw rotation speed △T, 2 set temperature correction temperature ΔT4: Correction temperature according to screw shape △T,: Correction temperature according to resin type (4) Control method: A method is adopted in which a precise set temperature is calculated using a formula and then commanded to the temperature controller 5.

Cultivation setting temperature expansion = Current setting temperature - (y - z) It is good, but if it is 1, the desired resin temperature may be exceeded.

Under the above conditions, the screw rotation speed was set to 3011311.6
The actual 8A temperature A was measured by changing it to 0rll11.70A, and the difference with the desired resin temperature ME was compared. Table 1 is
After the push-opening starts, the cylinder temperature y1 of each zone after two to four set temperature change commands, the predicted resin temperature iY, the actual resin temperature fJtA, the desired resin temperature E, and A-E are shown.

The actual resin temperature Iwh was measured by drilling a through hole in each zone of the cylinder and inserting a temperature measuring element until it came into contact with the bath melted resin.

From Table 1, the deviation IA-El between the actual resin temperature A and the desired resin temperature E is approximately 2.0° C. at most, and the temperature deviation is significantly smaller than in the conventional method described below.

Next, a conventional example to which a conventional temperature control method is applied will be shown.

[Conventional Example 1] Extrusion work was carried out in the same manner as in the example except that the same extruder as in the example was used, and each zone was adjusted to 120°C using a regular PrD temperature controller for temperature control. I did it.

This temperature control method is a conventional general extension-like temperature control method shown in FIG. Table 2 shows cylinder temperature y1 actual resin temperature A1 desired resin temperature E and A-K.

Table 2 From Table 2, it can be seen that the deviation IA-El between the removed resin temperature A and the desired resin temperature wave E is about 8° C. at maximum. Na2,
If the screw rotation speed is further increased during this one shift, the deviation (A-E) may exceed 10°C. In such a state where there is a large temperature deviation, problems arise in terms of the quality of the extruded product.

[Conventional Example 2] Extrusion work was carried out in exactly the same manner as in Example 1, except for the winter melon, using the following equation as the pattern fat absorption prediction equation.

This method is shown in Japanese Patent Application No. 191906/1982.
c is an example of a temperature control method.

Y = y + △T1 + ∆Tt Y: Predicted resin temperature y: 11M1 of the cylinder by thermocouple C △T1: Corrected temperature by temperature △T2: Persimmon positive temperature suction by screw rotation speed Table 3 shows the cylinder in the valley zone. Regards, Yoike"Resin temperature Y1 Actual Kizuki Umenmaru A1 Hopeful month □ Go Onsaka E and A-E are shown.

The deviation IA-El between the temperature A of the resin and the desired resin temperature E is approximately 4.5°C at maximum, which is smaller than that of Conventional Example 1. , the temperature control of the tree J1i cannot be said to be yet dense.

As explained above, the resin temperature control method for the plastic molding machine of the present invention involves measuring the hot liquid in the twin cylinders for plastic molding, and adjusting the temperature to the room temperature, screw rotation speed,
Among the parameters that fluctuate the resin temperature, such as screw shape, set temperature wave, and resin wires, calculate the resin by adding the corrected temperature calculated from at least three parameters including room temperature and screw rotation speed. The resin temperature is controlled based on the deviation between the predicted resin temperature and the desired resin temperature. Therefore, with this temperature control method, even if the above-mentioned parameters change, the temperature of the desired resin IA can always be maintained at a high circulation rate. Therefore, by increasing the discharge amount, reducing scorch, and saving thermal energy, high-quality molded products can be manufactured at low cost. In addition, compared to the method of directly contacting the temperature measuring element with the thermoplastic resin, there is almost no need to replace the temperature measuring element.
Furthermore, troubles such as damage to cylinders and screws are eliminated, and long-term continuous operation during molding is possible.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the extrusion method applied to the conventional side fat temperature control method, Figure 2 is a graph showing the IA relationship between room temperature and △T1, Figure 3 is a graph showing the relationship between screw rotation speed and △T, Figure 4 is a schematic configuration diagram showing an example of an extruder to which the temperature control method of this invention is applied, and Figure 5 is a diagram showing the relationship between
FIG. 6 is a schematic cross-sectional view showing the mounting state of the temperature measuring element shown in the figure, and FIG. 6 is a block diagram showing an example of a control system used in this temperature control method. ■...Extruder, 2...Cylinder, 5...Temperature controller, 6...Heating device, 7...Q cooling device, C...Hot basket cutting, 9...Rotary power generation Machine, 10... Temperature measuring resistor, 1
3...Microprocessor. Applicant Fujikura Electric Wire Co., Ltd. Figure 1 [ Figure 2 111--→-'1jiF'C] Figure 3 Inside Fujikura Electric Wire Co., Ltd., 5-1 Kiba-chome, Koto-ku, Tokyo.

Claims (1)

[Claims] The temperature of the cylinder of a plastic molding machine is measured, and the information includes room temperature, screw rotation speed, and screw shape. Bath M resin temperature in the cylinder is determined by adding correction temperature from at least 3 or more parameters including room temperature and screw rotation speed among the parameters that fluctuate the bath RA resin temperature such as setting temperature and other types of resin. A resin preservation control method for a plastic molding machine that involves predicting the temperature, determining the deviation between the predicted temperature and the rough mold resin temperature, and controlling the temperature of the molten resin in the cylinder based on this deviation. .