JPH0675908B2 - Film thickness control device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an automatic die lip control device applied to extrusion or cast molding production of a film or sheet production apparatus.

[Conventional technology]

In an extrusion molding or casting apparatus for producing a sheet or film, it is necessary to produce a product in which the thickness of the sheet or film is kept at a predetermined value. An example of a conventional device is shown in FIGS.
It will be described with reference to the drawings.

The resin melted by the extruder 1 is sent to the die 2. The molten resin is spread in the longitudinal direction of the slot by the manifold 3, hangs down from the discharge port 5 of the slot of the die lip 4, cooled by the cooling roller 6, solidified into a film 7, and wound on the winder 10. The thickness meter 11 measures the thickness shape of the film 7. As the adjusting mechanism of the die lip 4, as shown in FIG. 10, a large number of heaters 12 are distributed and arranged in order to change the discharge amount of the resin along the longitudinal direction of the slot of the die lip. Has been done. The heater 12 is embedded in the die lip 4, and by changing the heat generated by the heater, it is possible to change the resin discharge amount by changing the viscosity of the resin at that location and changing the flow velocity. Therefore, the thickness of the film 7 can be automatically controlled by changing the heat generated by the heater 12. FIG. 11 shows a block diagram of thickness control for one operating end of the heater 12. The difference between the film thickness at a certain position measured by the thickness gauge 11 and its set value is input to the controller 13. The controller 13 calculates and outputs the required heat generation of the heater 12 corresponding to the thickness and the portion measured by the total 11. When the heat generated by the heater 12 changes, the amount of resin discharged in the die lip 4 changes, and the film thickness at the corresponding portion of the heater 12 changes so that the thickness can be controlled. The thickness control over the entire film width could be performed by preparing the control loop of FIG. 11 for the number of locations where the thickness control is performed.

[Problems to be solved by the invention]

The conventional control system shown in FIG. 11 has the following problems.

(1) A large number of thickness gauges 11 cannot be installed because they are expensive. Therefore, since the thickness meter 11 measures the thickness by reciprocating in the width direction of the film 7, the thickness of the film 7 at the position corresponding to one of the heaters 12 is obtained every tens of seconds. . Using this thickness measurement value, one heat generation amount command of the heater 12 at the corresponding position can be updated only every tens of seconds. Therefore, there is a limit to the rapid response of the thickness control.

(2) Since the current thickness meter 11 uses the radiation caused by the natural decay of radioactive substances, it is inevitable that the thickness measurement value inevitably has a statistical variation and the thickness measurement value includes an error. Therefore, using the thickness measurement value of the thickness gauge 11 as the feedback signal of the control system inevitably causes performance deterioration of the control system due to an error in the measurement value.

(3) The thickness gauge 11 is installed on the downstream side of the cooling roller 6. Therefore, there is a "dead time delay" until the film 7 reaches the position of the thickness gauge 11 after the heater 12 is operated until the thickness change of the film 7 is measured. Since this dead time delay is a non-negligible amount, it causes performance deterioration of the control system.

[Means for solving problems]

 The present invention takes the following means to solve the above problems.

In an extrusion molding or casting molding apparatus having a plurality of heaters for adjusting the discharge amount of the molten resin along the longitudinal direction of the die slot, a thermometer is provided near the discharge port of the downstream die slot corresponding to each heater. and, setting value signal _{ri (tk +1) ≡ri (k} + 1) ( variable k + 1 follows the signal indicates tk ₊₁₎ of the discrete time tk ₊₁ any of the above thermometer i is the addition input,
A subtractor into which the signal yi (k + 1) from the sampler described later is subtracted and input, an integrator into which the output of the subtractor is input, and the output x _I (k + 1) of the integrator is input as one input. A heater generated heat controller, a die lip temperature process to which the output (k + 1) of the heater generated heat controller (→ indicates a vector and the same below) is input, and an output (vector) of the same die lip temperature process are connected. The thermometer and the output (vector) of the thermometer are input, and its own output (k +
Sampler for subtracting yi (k + 1) from 1) into the subtractor, and output (k + 1) of the heater generation heat controller
, The output of the same memory (k) and the output of the sampler (k + 1) are input A film thickness control apparatus comprising a plurality of basic control systems each including an integrator for inputting as a second input to the heater generation heat controller.

[Action]

In the above means, the subtractor is set to the temperature set value ri (k + 1)
From the signal (k + 1) passing through the sampler of the thermometer described later, the signal yi (k + 1) corresponding to the same thermometer is subtracted.
The integrator integrates the output of the subtractor. The next heater generated heat controller is the output from the integrator x _I (k + 1) and the output from the observer described later. In response to this, a heater generated heat command (k + 1) is issued. The die lip signal process receives the heat generation command (k + 1) from the heater and outputs the die lip temperature. The thermometer receives the die lip temperature, passes through the sampler, and outputs its signal (k + 1).
To the observer. The memory receives the heater generated heat command (k + 1) and outputs the memory output (k) of the time tk before that. The observer receives the output (k) of the memory and the output (k + 1) of the sampler and estimates the value. Is sent to the heater generation heat controller. The above operation is sequentially repeated for each discrete time. It is possible to perform highly accurate thickness control over the entire width of the film formed by the plurality of basic control systems that operate in this way.

The amount of resin discharged at a certain location along the longitudinal direction of the slot of the die lip 4 is substantially proportional to the temperature of the die lip itself at that location. Therefore, if the temperature of the die lip 4 at a certain portion is raised, the amount of resin discharged at that portion is increased and the film thickness at that portion is increased. From this, by controlling the temperature of the die lip 4, the thickness of the film 7 can be set to a predetermined profile. That is, the film thickness control can be replaced with the temperature control of the die lip 4. FIG. 4 shows the heat generation amount of all the heaters arranged along the longitudinal direction of the slot of the die lip.
Surface temperature in the vicinity of the discharge part 5 of the slot of the die lip 4 when lowered from 13 W to 6.5 W (hereinafter referred to as die lip temperature) (temperature at the position indicated by X in FIG. 2) (FIG. 4 (1)) , And the resin discharge amount of the entire die lip ((2) in the same figure) and the film thickness ((3) in the same figure) are shown as simulation results. Experimental results are also shown for the die lip temperature. FIG. 4 shows the results of dynamic heat-fluid analysis inside the die lip. As can be seen from the figure, as the die lip temperature decreases, the resin discharge amount of the die lip decreases, and the film thickness decreases accordingly. From this, it can be confirmed that the die lip temperature and the film thickness have a substantially proportional relationship. Thus, by replacing the film thickness control with the die lip temperature control, the following can be performed.

(1) By using a generally inexpensive thermometer instead of the thickness gauge 11, a large number of thermometers can be installed for measuring the die lip surface temperature along the width direction of the die lip, so that the temperature signal is continuous. It can be obtained in time or at very short time intervals. Therefore, the heat generation amount command of the heater 12 can also be updated at short time intervals, and the responsiveness of the film thickness control is improved.

(2) In order to measure the surface temperature of the die lip, not only contact type thermometers such as thermocouples but also non-contact type thermometers are possible. However, both methods are currently inexpensive and highly accurate. You can get a total. Therefore, in any of the temperature measuring methods, the performance of the control system is not deteriorated by the measurement signal including a statistical error as in the thickness gauge.

(3) The thermometer, which is the detecting end, is the heater 12 which is the operating end.
Since the temperature of the die lip itself in which is embedded is measured and output as a feedback signal, there is no intervening dead time due to film flow delay as in the case of a thickness gauge. Therefore, the performance of the control system is not deteriorated due to the dead time at the detection end.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS.

Extruder 1 (Fig. 2), die 2 attached to the extruder 1,
A die lip 4 having a slot discharge port 5 is provided below the die 2, and a plurality of heaters 12 (FIG. 3) are arranged above the discharge port 5 along the longitudinal direction of the slot. In the vicinity of 5, a plurality of thermometers 30 are arranged at downstream positions corresponding to the respective heaters 12 described above. A cooling roller 6 is arranged downstream of the die 2, and a winding machine 10 is arranged beside the cooling roller 6. Further, a controller of one embodiment of the present invention, which will be described later, for controlling the heater 12 by the thermometer 30 is provided.

In order to make the description easy to understand, the idea leading to the present embodiment will be described first, and finally the configuration and operation will be described.

In order to make the explanation concrete, five heaters h1 to h5 shown in FIG. 5 among a plurality of heaters 12 and thermometers 30 arranged on the die lip 4 and the temperature of the die lip corresponding to each heater position are shown. total s1~s5 of using the measured value the thermometer s3 temperature (hereinafter die lip temperature hereinafter) is controlled y ₃ (t) to a predetermined value considering the "basic control system". Consider the same temperature y ₃ two neighboring two heaters h1 besides heater h3 to control (t), h2 and heater h4, h5, the heater h1 to temperatures y ₃ (t), h2 and heater h4, This is because the control system is designed in consideration of h5 interference. If there are five or more heaters 12, the heaters outside the heaters h1 and h5 have a small effect on the temperature 3 and are ignored. The heat generated by the heaters h1 to h5 is respectively u ₁ (t), u ₂ (t), u ₃ (t), u
₄ (t), u ₅ (t), and the die lip temperature is y ₁
Let (t), y ₂ (t), y ₃ (t), y ₄ (t), y ₅ (t).
Let Ui (s) and Yi (s) (i = 1 to 5) be the Laplace transforms of ui (t) and yi (t) (i = 1 to 5).
(S) and Yi (s) are related by the following transfer function matrix G (s). Y (s) = G (s) U (s) That is, g ₁ (s) is a transfer function that considers the time change of the die lip temperature y ₃ (t) when changing only the heater h 3, for example.
g ₂ (s) is a transfer function that gives the time variation of the same temperature y ₃ (t) when only the heater h2 or the heater h4 is changed. g
₃ (s) is a transfer function which gives the time variation of the same temperature y ₃ (t) when only the heater h1 or the heater h5 is changed.
The asymmetric term of the transfer function matrix G (s) of the equation (1) represents the interference of the adjacent heater with the die lip temperature.

Input Ui (s) and output Yi (s) of equation (1) (i = 1 to 5)
The following equation of state, which is convenient for control system design, is used to express the relationship between.

(T) = Ax (t) + Bu (t) (2) y (t) = Cx (t) (3) where x is a state vector and u is an input vector u (t) = [u ₁
(T), u ₂ (t), u ₃ (t), u ₄ (t), u ₅ (t)] ^T , (T
Represents transposition), y is an output vector, and y (t) =
[Y ₁ (t), y ₂ (t), y ₃ (t), y ₄ (t), y ₅ (t)] ^T
Is. Equations (2) and (3) are controllable and observable. From the expressions (2) and (3), the relationship between the input u (t) (heat generated by the heater) and the output y (t) (detection value of die lip temperature) is shown in FIG. Die lip temperature y ₃ (t)
In order to avoid the influence of disturbance due to heat conduction from the adjacent heater to control the set value to the set value, the detected value y ₃ (t) of the die lip thermometer s3 and the set value r ₃ (t) are used as the disturbance compensation.
Introducing an integrator for the deviation ε (t) = r ₃ (t) −y ₃ (t). In the following, the setting r ₃ (t)
= 0. The integrator time-integrates the control deviation ε (t) up to the current time t. The output x _I (t) of the integrator is represented by the following equation.

C ₃ represents the third row of the C matrix in equation (3). (4) _I (t) from the equation = - from _{C 3 x (t) ...... (} 5) (2) (5) formula, enlarged system state equation as follows is obtained.

State vector of expanded system (t) = [x _I (t), x (t)]
^{Using T} , the equation (6) is expressed as follows.

In reality, since the die lip temperature y (t) is obtained in discrete time, the heater generated heat u (t) is also updated in discrete time. Therefore, equation (7) is displayed as a discrete time system. For example, when the state (t) at time t = tk is represented by (k), the equation (7) is represented by the following equation.

(K + 1) = x (k) + u (k) (9), corresponds to the matrix in the discrete time system.

The state feedback gain matrix for equation (9) is
If [k ₁ , K ₂ ], then the input u (k) is k ₁ represents the first column of the matrix and K ₂ represents the second and subsequent columns.

In the equation (10), the state x _I (k) can be actually obtained as the output of the integrator, but the state x (k) can be obtained by the observer described later. At this time, if the feedback gain matrix is determined so that all the eigenvalues of the matrix (−) are in the stable region (within the circle having the center at the original rotation and the radius of 1), the die lip temperature y ₃ (k ) Can be stably controlled to a predetermined value. Moreover, in the present embodiment, since the thermometer is used instead of the thickness gauge, the discrete time interval T = tk _{+ 1} -tk can be arbitrarily reduced, and the quick response of the control system is restricted from the discrete time interval T. It will not be done.

Next, an observer is used to obtain the state feedback amount x (k) in equation (10). Observer is die lip temperature y (k)
To output an estimate of the state x (k) from. Next, design the observer.

Equations (2) and (3) are converted into the following discrete time system.

x (k + 1) = Fx (k) + Gu (k) …… (11) y (k) = Cx (k) …… (12) The estimated value of the state x (k) at t = tk. Express with.

Estimated value at t = tk ₊₁ Is calculated as follows. An estimate of the expected at t = tk ₊₁ at the beginning of the (k + 1) at t = tk Is calculated from Eq. (11) as follows.

Estimated value at t = tk ₊₁ Is calculated from the following equation using the predicted value (k + 1).

Where L is the feedback gain matrix of the observer, and the estimated value Is set so as to converge to a correct value.

(13), (14) According to the equation, t = state x at tk ₊₁ die lip temperature y (k + 1) at the same time is inputted t = tk ₊₁
(K + 1) can be estimated. Estimation error at this time Can be expressed by the following equation.

Therefore, if the gain matrix L of the observer is determined so that all the eigenvalues of the matrix (F-LCF) are in the stable region (within the circle with the center at the origin and having a radius of 1), the estimation error becomes smaller with the passage of time. be able to. Therefore, the state x (k) in equation (10) is the estimated value of the observer. Can be replaced with At this time, the heater generated heat command value u (k) is expressed by the following equation.

In this embodiment, since the thermometer is used instead of the thickness gauge,
Since the detection value y (k) does not include dead time and the discrete time interval can be arbitrarily reduced, it is possible to design an observer with fast convergence. Furthermore, the detection signal y
Since (k) is obtained from the thermometer, the accuracy is good, and the die lip temperature control can be performed with high accuracy.

From the above, the configuration of the control device (FIG. 1) including the "basic control system" for performing die lip temperature control instead of film thickness control will be described below. The double line in FIG. 1 indicates the vector quantity.

From the signal r ₃ (k + 1) of the die lip temperature set value a to the signal (k + 1) from the sampler 21 described later, y ₃ (k + 1)
Subtractor 22 for subtracting, an integrator 23 for inputting the output of the subtractor 22, an output x _I (k + 1) of the integrator 23, and an observer described later.
24 outputs Heater generated heat controller 25 for inputting, die lip temperature process 26 for inputting the output (k + 1) of the heater generated heat controller 25, thermometer 20 for inputting the output of the die lip temperature process 26, output of the thermometer 20 , A memory 27 for inputting the output (k + 1) of the heater generated heat controller 25, an output (k) of the memory 27 and the sampler 21.
Output signal in response to the output (k + 1) of To the heater generation heat controller 25. The output of the die lip temperature process 26 is the die lip temperature b. The above is the configuration of the basic control system that mainly controls the heater h3. Therefore, a plurality of similar products are provided. The action is as follows.

(1) time t = new temperature detection value of the die lip in _{tk +1 y (k + 1)} (y 1 (k + 1), y 2 (k + 1), y 3 (k +
1), y ₄ (k + 1), y ₅ (k + 1)) includes a thermometer 20 and a sampler 21 including the temperature sensors s1 to s5.
Obtained through.

(2) Of the die lip temperature detection values y (k + 1), y ₃
(K + 1) is input to the subtractor 22, which subtracts a temperature deviation ε (k + 1) from the die lip temperature set value r ₃ (k + 1) =
r ₃ (k + 1) −y ₃ (k + 1) is output.

(3) The integrator 23 receives the temperature deviation ε (k + from the subtractor 22
1) is input and the time integral value of the temperature deviation is output from the following equation.

x _I (k + 1) = x _I (k) +0.5 (tk ₊₁ −tk) (ε (k)
+ Ε (k + 1)) (17) where ε (k): Previous die lip temperature was detected (time t =
temperature deviation x _I (k) at tk): The output of integrator 23 at time t = tk
It acts as a disturbance compensator that compensates the disturbance heat that fluctuates the die lip temperature y ₃ with the heat generated by the heater so that the die lip temperature y ₃ always matches the set value.

(4) From the above equations (13) and (14) To calculate. That is, the heater generated heat u (k) and the die lip temperature detection value y (k + 1) calculated at time t = tk are input to the observer 24, and the state estimation value at time tk _{+ 1} is estimated. Is output.

(5) for calculating the expression (16) from time t = tk ₊₁ after new heater heat generated command u (k + 1). That is, the output of the integrator 23 x _I (k + 1) and the output of the observer 24 Is input to the heater generation heat controller 25, and the heater generation heat command value u (k + 1) is output according to the equation (16).

(6) above control operation, the time t = to tk ₊₂ next die lip temperature detection value y (k + 2) is performed for each obtained from the sampler 21.

As a specific example, the transfer functions g ₁ (s), g ₂ (s), of the equation (1),
The simulation result of the die lip temperature control according to the present embodiment when g ₃ (s) is given by the following equation is shown.

ui (t) (i = 1 to 5) indicates the amount of change in heat generated by each heater [unit kcal / s], and yi (t) (i = 1 to 5) indicates the temperature change of the die lip corresponding to each heater position. (° C) is shown.

Equations (18) to (20) consisting of g ₁ (s), g ₂ (s), and g ₃ (s) are controllable and observable equations of state that represent the input-output relationship of equation (1), (2) , (3) is obtained. As a result, the 23rd order equation of state was obtained.

(7) Determination of state feedback bag gain matrix (10)
The state feedback gain matrix of the equation is obtained as a solution of the optimal regulator problem for the extended equation (9). The discrete time interval T was T = 10 seconds. As a result of obtaining the state feedback gain matrix using an appropriate evaluation function, the following values are mainly obtained as the eigenvalues of the matrix (-).

0.957, 0.855 ± 0.089j, 0.85 ± 0.089j, 0.823 ± 0.16j, 0.82
± 0.16j Eigenvalues other than the above are not listed because their absolute values are small and attenuation is fast. All eigenvalues are radius 1 centered on the origin
You can see that stable control is possible because it is inside the circle. Since the eigenvalue with the slowest decay is 0.957, if the settling time Ts is defined with a control error of 1%, (0.957) ¹⁰⁵ ≈0.01
The settling time Ts can be predicted to be about 17.5 minutes as follows.

Ts = T × 105/60 = 10 × 105/60 = 17.5 minutes (8) Determination of the observer feedback gain L (14)
The feedback gain matrix L of the observer of the equation is (11),
It was calculated for equation (12). The matrix L is a matrix {F ^T − (CF)
^We obtained the solution of the optimal regulator problem so that ^T L ^T } has a stable eigenvalue. As a result of obtaining the gain matrix L using an appropriate evaluation function, the following values are mainly obtained as the eigenvalues of the matrix (F-LCF).

0.914, 0.895, 0.879 ± 0.093j, 0.537 ± 0.022j Eigenvalues other than the above are not listed because their absolute values are small and their attenuation is fast. Since all the eigenvalues are within the circle with the radius of 1 centered on the origin, it can be seen that the estimation error decreases with the passage of time. Since the slowest eigenvalue of the time To required for the estimation error to decay to 1% of the initial value is 0.914, it can be predicted as follows from (0.914) ⁵¹ ≈0.01.

To = T × 51/60 = 10 × 51/60 = 8.5 minutes FIG. 7 shows a simulation example of the control result obtained by performing the control calculation using the gain matrix obtained from the above. Figure 7 (a) shows the die lip temperature y ₃ (t).
The time course of changes in the _five die lip temperatures y _{1 to} y 5 when the set value (hereinafter abbreviated as y ₃ ) is changed stepwise by 5 ° C. is shown. Similarly, FIG. 7 (b) shows the change over time in the amount of heat generated from each heater u ₁ (t) to u ₅ (t) (hereinafter abbreviated as u _{1 to} u ₅ ) at that time, and FIG. c) shows the change over time in the thickness variation of the film at the corresponding position. It is shown from the change of the set value until 11 minutes later. The control deviation of the lip temperature y ₃ after 11 minutes is about 0.23 degree, which is a deviation of 4.6% with respect to the set value change of 5 ° C. . From the slowest eigenvalue 0.957,
(0.957) From ⁷⁰ ≈ 0.046, the time Ts until the control deviation becomes 4.6% is predicted to be Ts = T × 70/60 = 700/60 = 11.7.
It is possible to support the control result of FIG. Die lip temperature than Figure 7 (a) is changed substantially symmetrically with respect to the die lip temperature y _3. When the die lip temperature y ₃ is changed by 5 ° C, the adjacent lip temperature also rises. When actually applying the control according to the present embodiment, by applying the same "basic control system" as applied to the die lip temperature _{y 1, y 2, y 4} , the die lip temperature y ₃ with respect to y _5, It suffices to cancel out such an interference effect. The die lip temperature y ₃ that has changed substantially symmetrically from raising 5 ° C. with respect to FIG. 7 (b) a heater generating heat even heater generating heat u ₃ than, of course, the heater h ₃
Heat generated u ₂ of the change in the generated heat u ₃ is the largest heater h2 h4
And u ₄ have the next largest change, the heat generated by heaters h 1 and h ₅ u ₁ and u ₅
Has the smallest change. From FIG. 7 (a) (b), increasing the die lip temperature y ₃ it can be seen that are performed by increasing lip temperature y _{1 around, y 2, y 4, y} 5 together. 7th
FIG. 7 (c) shows the elapsed time of the film thickness at the corresponding position when the heat generated by the heater changes as shown in FIG. 7 (b). It can be seen that the film thickness at the position corresponding to the heater h3 has increased by about 23μ after 11 minutes. Comparing FIGS. 7 (a) and 7 (c), it can be seen that the film thickness can be controlled by controlling the die lip temperature. FIG. 8 shows the control result when 4.2 W of disturbance heat is added to the heater h3 in steps. Figure 8 (a) is a die lip temperature y ₁ ~y ₅
Shows the lapse of time in the amount of change, and FIG. 8 (b) shows the lapse of time in the amount of change of the heater generated heats u _{1 to} u ₅ . In FIG. 8, a feedback gain matrix that emphasizes disturbance compensation is used. The slowest eigenvalue is 0.931, and the settling time until the control deviation becomes 1% is about 11 minutes.

As shown in FIG. 8 (a), the die lip temperature y ₃ is once increased by the disturbance heat of the heater h3, but the heat generated by the heaters h1 to h5 is increased.
By changing u _{1 to} u ₅ , the die lip temperature y ₃ returns to the original setting value. It can be seen that the introduction of the integrator in this "basic control system" provides excellent disturbance compensation. As can be seen from FIG. 8 (a), and disturbance heat enters the heater h3, die lip temperature y ₃ is the die lip temperature y _{1 around, y 2, y 4, y} 5 is lowered increases, the disturbance heat It can be seen that the die lip temperature y ₃ is returned to the set value by letting it escape to the surrounding die lip.

Heat generated u ₃ of the heater h3 from FIG. 8 (b) is naturally lowered. In addition, the heat generated by the heaters in the surroundings u ₁ , u in order to lower the ambient lip temperature around the die lip temperature y ₃ and allow external heat to escape
Initially, ₂ , u ₄ and u ₅ dropped. The generated heat u ₁ and u ₅ of the heaters h 1 and h ₅ has the largest decrease amount, and the generated heat u ₃ of the heater h 3 has the next largest decrease amount. Heat generated by heaters h2 and h4 u ₂ and u
_{For 4} , the amount of heat generated is gradually restored. From the above, the influence of the disturbance heat applied to the heater h3 is
It is extinguished by the decrease in the amount of heat generated by h3 itself and the loss of heat to the die lip around the heater h3. The decrease in the die lip temperature around the die lip temperature y ₃ caused by the temperature control of the die lip temperature y ₃ against the disturbance heat is as follows for each die lip temperature y ₁ , y ₂ , y ₄ , y ₅ . The same “basic control system” as that applied to y ₃ may be applied to cancel such interference effect. FIG. 8 (c) shows the temporal change of the film thickness at the corresponding position when the disturbance heat enters the heater h3 and the heat generated by the heater changes as shown in FIG. 8 (b). It can be seen that the film thickness at the position corresponding to the heater h3 has returned to the set value. By comparing FIGS. 8 (a) and 8 (c), it can be seen that the film thickness can be controlled by controlling the die lip temperature. The operation of one basic control system has been described above, but the same applies to other basic control systems. As described above, the thickness control over the entire width of the film can be improved by measuring the temperature of the die lip without measuring the film thickness, which is difficult to measure, and by receiving a plurality of "basic control systems".

〔The invention's effect〕

 The present invention has the following effects.

Highly accurate and highly accurate die lip temperature by detecting the temperature of the die lip itself that can improve accuracy, shorten the data sampling time interval and prevent dead time compared to the film thickness measurement value and use it as a feedback signal It is possible to control the film thickness, so that the film thickness control can be highly accurate and the responsiveness can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing the structure of a controller of one embodiment of the present invention, but showing the structure for a heater h3, FIG. 2 is a diagram showing the conceptual structure of a film manufacturing plant of the same embodiment, and FIG. A heater arrangement diagram embedded in the die lip of the figure, FIG. 4 is a simulation result diagram showing changes of the die lip temperature, the resin discharge amount, and the film thickness with respect to the change of the heat generation amount of the heater of the embodiment, and FIG. FIG. 6 is a diagram showing the correspondence between heater positions of a set and five sets of die lip temperature detection positions. FIG. 6 is a block diagram showing a dynamic mathematical model of the die lip temperature of the same embodiment. FIG. 7 is a simulation result of the same embodiment (die lip FIG. 8 is a diagram of a simulation result of the same embodiment (when disturbance heat is applied to the heater), and FIG. 9 is a conventional film manufacturing plant. Conceptual configuration diagram, Fig. 10 is a heater arrangement diagram embedded in the die lip of Fig. 9, Fig. 11 is a block diagram of the control device of Fig. 9, 1 ... Extruder, 2 ... Die, 3 ... … Manifold, 4 …… Die lip, 5 …… Die lip slot discharge port, 6 …… Cooling roller, 7 …… Film, 10 …… Winder, 11 …… Thickness gauge, 12
...... Heater, 13 ...... Controller, 30 ...... Thermometer, l ...... Longitudinal direction of die lip slot, a ...... Die lip temperature set value, b ...... Die lip temperature, 20 ...... Thermometer, 21 ... … Sampler, 22 …… Subtractor, 23 …… Integrator, 24 …… Observer, 25 …… Heater generation heat controller, 26 …… Die lip temperature process, 27…
… Memory, p …… Set value of film thickness, q …… Film thickness.

Claims (1)

[Claims] 1. An extrusion molding or casting molding apparatus comprising a plurality of heaters for adjusting the discharge amount of molten resin along the longitudinal direction of a die slot, in a downstream position corresponding to the heater near the discharge port of the die slot. A thermometer is installed at the set value signal ri (tk ₊₁ ) of the discrete time tk ₊₁ of the above thermometer i.
≡ri (k + 1) (hereinafter the variable k + 1 of each signal indicates tk ₊₁₎ is input summing the signal yi (k from below sampler
+1) is subtracted and input, an integrator to which the output of the subtractor is input, a heater generation heat controller to which the output x ₁ (k + 1) of the integrator is input as one input, The die lip temperature process to which the output (k + 1) of the heater generated heat controller (→ indicates a vector) is input, the thermometer to which the output (vector) of the die lip temperature process is connected, and the thermometer of the thermometer. A sampler for inputting an output (vector) and subtracting yi (k + 1) of its own output (k + 1) into the subtractor, a memory for inputting the output (k + 1) of the heater generation heat controller, and the same memory Output (k) and output of the sampler (k + 1)
Is input and self output A film thickness control apparatus comprising a plurality of basic control systems each including an integrator for inputting as a second input to the heater generation heat controller.