JPH03275325A - Temperature control device of t-die - Google Patents

Abstract

PURPOSE:To make it possible to control the temperature at the deep position of a T-die by following up to temperature set point by a method wherein temperature set point is corrected on the basis of the temperature difference between a first and a second temperature detection signals and the controlling of energizing amount supplied to heaters is performed on the basis of the deviation between the corrected temperature set point and the first detected temperature indicated by a first temperature detection signal. CONSTITUTION:With a second temperature sensor 16, which is newly provided near a resin rich area so as to measure the temperature of a T-die 11, second detected temperature is sampled with a predetermined period after the counting for the predetermined setting time under the given temperature set point of the T-die so as to calculate the rate of change of sampled value. When said rate of change is below set point, a compensated temperature value is calculated on the basis of the difference between a first and a second detected temperatures with a compensator 18 of set point in order to obtain a corrected temperature value by summing up the compensated temperature value and the temperature set point. Next, the energizing amount to heaters 14 is controlled on the basis of the deviation between the corrected temperature value obtained as mentioned above and the first detected temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a temperature control device for controlling the temperature of a T-die used in an extrusion molding machine such as a laminator.

(Prior art) In general, laminators for forming film-like molded products are not used! WT die is used.

This T-die has an inlet port to which molten resin is supplied, a resin reservoir where the molten resin is temporarily stored, and a film-like resin connected to the resin reservoir (hereinafter simply referred to as a film).
This gap extends in the longitudinal direction of the T-die.

In such a T-die, it is necessary to control the T-die temperature to a preset temperature in order to improve the accuracy of the thickness of the film taken out from the gap.

Conventionally, when controlling the temperature of a T-die, a plurality of heating heaters are provided on the T-die surface along the extending direction of the gap, and a plurality of temperature heaters are provided in the T-die close to the heating heater. A sensor is provided to compare the set temperature value and the detected temperature value to control the amount of electricity supplied to the heating heater.

At this time, the position where the temperature sensor is provided (temperature measurement point) is selected to be a shallow position close to the heating heater as described above so that it can immediately respond to heat transfer from the heating heater.

As mentioned above, the influence of resin temperature on film thickness in a laminator is extremely large, so when the T-die temperature (temperature field) is stabilized by conventional temperature control based on the detected temperature value and the set temperature value, it has been empirically shown that the T-die temperature Other parts of (
Production operations are conducted taking into consideration the temperature stabilization time at the deep position of the T-die (near the resin reservoir).

(Problem to be solved by the invention) However, as mentioned above, since the production operation is started after determining the stabilization time of the deep position of the T-die, the resin temperature fluctuates due to various disturbances etc. during the production operation. In this case, there is a problem that it is difficult to control the temperature at a deep position of the T-die to follow the set temperature value.

Furthermore, since the resin temperature in the vicinity of the resin reservoir is not considered, temperature unevenness tends to occur in the longitudinal direction (width direction) of the T-die, which adversely affects the thickness of the film taken out from the gap, resulting in uneven thickness. There is.

An object of the present invention is to provide a T-die temperature control device that can control the temperature at a deep position of the T-die in accordance with a set temperature value.

Another object of the present invention is to provide a T-die temperature control device that does not cause uneven thickness of the film.

(Means for Solving the Problems) According to the present invention, a molten resin is supplied, a resin reservoir portion for storing the molten resin, and a gap connected to the resin reservoir portion and extending in a predetermined direction are formed, It is used to control the temperature of the T-die from which the film-shaped resin is taken out from this gap, and there is a heater installed in the T-die to control the heating of the T-die, and a heater installed close to the heater to measure the temperature of the T-die. a first temperature sensor that measures the temperature of the T-die and outputs a second temperature detection signal, which is provided near the resin reservoir and outputs a second temperature detection signal; The set temperature value of the T-die is input, and when a predetermined set time has elapsed after inputting the set temperature value, the second detected temperature indicated by the second temperature detection signal is sampled at a predetermined period, and the rate of change of the sample value is measured. The first step is to calculate
and determining a corrected temperature value based on the difference between the first detected temperature and the second detected temperature, which are indicated by the first temperature detection signal when the rate of change becomes equal to or less than a preset value. a second means; a third means for obtaining a corrected temperature value by adding the corrected temperature value and the set temperature value; and a third means for calculating the corrected temperature value by adding the corrected temperature value and the set temperature value; There is obtained a T-die temperature control device characterized in that it has a temperature control means for controlling the amount of current applied to the heater based on the deviation.

(Function) In the present invention, a second temperature sensor for measuring the temperature of the T-die is newly provided near the resin reservoir, and when the temperature setting value of the T-die is given, a predetermined setting time is counted. Thereafter, the second detected temperature is sampled at a predetermined period and the rate of change of these sample values is determined. Then, when this rate of change becomes less than the set value, a corrected temperature value is calculated based on the difference between the first detected temperature and the second detected temperature, and the corrected temperature value is calculated by adding this corrected temperature value and the set temperature value. seek.

Next, using this corrected temperature value, the amount of electricity applied to the heater is controlled based on the deviation between the corrected temperature value and the first detected temperature.

In this way, since the heater energization amount is controlled using the corrected temperature value, that is, in consideration of the second detected temperature, T
The temperature at the deep position of the die can be controlled to follow the set temperature value, and uneven thickness of the film will not occur.

(Example) The present invention will be explained below with reference to Examples.

Referring to FIG. 1, the T-die 11 includes a T-die main body 12, and the T-die main body 12 is provided with an entry boat 13 to which molten resin is supplied.

The T-die main body 12 has a first resin passage 12a as shown in the figure.
is formed, and this first resin passage 12a is connected to a resin reservoir portion 12b that extends in the longitudinal (lateral) direction. Further, this resin reservoir portion 12b is connected to a second resin passage 12c extending in the longitudinal direction of the T-die, and a gap 12d extending in the longitudinal direction is formed at the lower end of the T-die main body 12.

As shown in the figure, the T-die main body 12 is divided into a plurality of (N) segments, and as is well known, the gap dimension (thickness) can be adjusted for each segment. A plurality of heaters 14 are arranged on the surface of the T-die main body 12. For example, heating heater 14
is arranged for each segment. In this case, a total of N heaters 14 will be provided. Furthermore, a first temperature sensor (for example, a thermocouple) 15 is embedded in each segment in the T-die main body 12 (referred to as a first temperature measurement point) near the heating heater 14, and The temperature is measured and a first temperature detection signal is output. Also, in the vicinity of the resin reservoir portion 12b (
A second temperature sensor (for example, thermocouple) 1 is installed in each segment in the T-die body 12 (referred to as a second temperature measurement point).
6 is embedded, and measures the temperature of the T-die and outputs a second temperature detection signal.

Each heater 14 is connected to a temperature regulator 17, and the temperature regulator 17 controls the energization as described later. That is, each heating heater 14 is independently controlled to be energized. The first and second temperature sensors 15 and 16 are connected to a set value correction device 18 and also to a display device (not shown), and the set value correction device 18 includes an adder 18a and a set value correction calculation section 18b. ing. Further, the first temperature sensor 15 is connected to a temperature regulator 17.

Here, referring also to Fig. 2, when driving the laminator, first the resin temperature value (TA) is set by the operator.
is given to the set value correction device 18. At this point, there is no output from the set value correction calculation section 18b, and the set temperature value (T
A) is input to the temperature controller 17 via the adder 18a. The temperature regulator 17 then sets the set temperature value (TA) and the first detected temperature value (ta) indicated by the first temperature detection signal.
) is used to control the amount of electricity supplied to the heating heater 14.

By supplying heat from the heating heater 14, first the first detected temperature (ta) at the first temperature measurement point increases,
Follows the set temperature value (TA). The heat from the heating heater 14 is also transmitted to the second temperature measurement point, and the second detected temperature also gradually increases.

Generally, the first detected temperature (t
a) and the second detected temperature (tb) reach an equilibrium state.

That is, the first detected temperature is balanced to the set temperature value (TA), and the second detected temperature is balanced to a temperature lower than the set temperature value (TA).

In the present invention, the set value correction device 18 adjusts the set temperature value (TA)
When received, a preset time (waiting time) is counted. This set time is set based on the shape and heat capacity of the T-die.

When the above set time has elapsed, the set value correction calculation section 18b
samples the second temperature detection signal at a predetermined period (for example, every 10 seconds), calculates the difference between the current sample value and the previous sample value, and uses this difference as the rate of change (change value). . When this change value becomes less than a predetermined value (for example, when the steady state is reached, in Figure 2, the period from the elapse of the waiting time until the above predetermined value is reached is the steady state monitoring section), the set value The correction calculation unit 18b determines that the second detected temperature has reached a steady state, and adjusts the first detected temperature (ta).
The corrected temperature value ΔTA is calculated from the second detected temperature (tb) using the following equation (1).

ΔT A −K X (t a −t b ) ・=
(1) Here, K is a parameter, expressed as K - f (ta) as a function regarding the first detected temperature (ta), and is determined based on the shape and heat capacity of the T-die.

Furthermore, in practice, K is the production temperature in the laminator,
For example, a plurality of angles are prepared between 200 and 350 degrees. This parameter is stored in advance in the set value correction calculation section 18b. Therefore, as shown in Figure 3, the horizontal axis is (ta-
tb), and the vertical axis is ΔTA, then ΔTA−KX (t
a-t b) is represented by a straight line whose slope differs depending on the parameter K.

The corrected temperature value ΔTA calculated as described above is given to the adder 18g, where it is added to the set temperature value TA, and a corrected set temperature value (T-TA+ΔTA) is output. This corrected set temperature value (T) is given to the temperature regulator 17, and the temperature regulator 17 determines the amount of heater operation by, for example, PID control based on the deviation between the first detected temperature and the corrected set temperature value (T). is determined, and heating heater 1 is determined based on this operation amount.
Controls the amount of electricity supplied to 4.

As a result, as shown in FIG. 2, the first detected temperature is balanced to a temperature higher than the set temperature value (TA), and the second detected temperature is balanced to the set temperature (TA').

Here, when the set temperature value is changed from TA to TB, the set value correction calculation unit 18b stops leaving the corrected temperature value ΔTA. Then, the set value correction device t18 starts counting the set time (waiting time). After the set time has elapsed,
As described above, the set value correction calculation unit 18b samples the second temperature detection signal at a predetermined period (for example, every 10 seconds) to determine the rate of change. When this rate of change becomes equal to or less than a predetermined value, a corrected temperature value ΔTB is calculated from the first detected temperature (ta) and the second detected temperature (tb) based on equation (1) and is sent to the adder 18a. give. As a result, the adder 18a outputs the corrected set temperature value T"(T'--"r
B+ΔTs) is applied to the temperature controller 17. Temperature controller 1
7 is this corrected set temperature value T' and the first detected temperature (ta)
The amount of electricity supplied to the heating heater 14 is controlled based on the deviation from the above.

As a result, as shown in Figure 2, the first detected temperature once equilibrates to the set temperature value (Ts), and then
) will result in a higher temperature. On the other hand, the second detected temperature once becomes lower than the set temperature value (TB), and then equilibrates to the set temperature value (Ts).

(Effects of the Invention) As explained above, in the present invention, the set temperature value is corrected based on the temperature difference between the first and second temperature detection signals, and the set temperature value is indicated by the corrected set temperature value and the first temperature detection signal. Since the amount of electricity applied to the heater is controlled based on the deviation from the first detected temperature, the temperature at the deep position of the T-die can be controlled to follow the set temperature value, and the thickness of the film can be controlled. This has the effect that uneven thickness does not occur.

A diagram showing an example; FIG. 2 is a diagram for explaining the temperature control operation of the T-die temperature control device shown in FIG. 1; FIG. 3 is a diagram showing the relationship between the corrected temperature value ΔTA and the temperature difference (ta-tb) FIG.

11...T-die, 12...T-die body, 13...
Inlet port, 14... Heating heater 15... First temperature sensor 16... Second temperature sensor 1
7... Temperature controller, 18... Set value correction device.

[Brief explanation of drawings]

Claims (1)

[Claims] 1. A T-die to which a molten resin is supplied, a resin reservoir for storing the molten resin, a gap connected to the resin reservoir and extending in a predetermined direction, and a film-like resin is taken out from the gap. A heater that is used when performing temperature control and is provided on the T-die to control heating of the T-die, and a heater that is provided close to the heater and measures the temperature of the T-die to generate a first temperature detection signal. a second temperature sensor that is installed near the resin reservoir and measures the temperature of the T-die and outputs a second temperature detection signal, and a set temperature of the T-die. When the value is input and a predetermined set time has elapsed after inputting the set temperature value, the second detected temperature indicated by the second temperature detection signal is sampled at a predetermined period and the rate of change of the sampled value is calculated. and a correction temperature based on the difference between the first detected temperature indicated by the first temperature detection signal and the second detected temperature when the rate of change becomes equal to or less than a preset value. a second means for calculating a value; and a third means for calculating a corrected temperature value by adding the corrected temperature value and the set temperature value.
and temperature adjustment means for receiving the corrected temperature value and controlling the amount of current applied to the heater based on the deviation between the first detected temperature and the corrected temperature value. Control device.