JP2010012675A - Temperature controllling method of die and its temperature regulator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To heighten the accuracy of the temperature controlling of the porion of a die lip at the tip of a die. <P>SOLUTION: In order to heighten the accuracy of the temperature control of the portion of the die lip, a secondary loops, which determine controlling outputs MV to heaters from detected temperatures PVs near the heaters, which are detected with heater temperature detecting sensors 12, and target temperatures SPs for in and around the heaters, and primary loops which determine target temperatures SPs for in and around the heaters to the secondary loops from detected temperatures PVm near the die lip detected with die lip temperature detecting sensors 13 and target temperatures SPm for in and around the die lip are constituted so as to perform a cascade control between the primary loops and the secondary loops. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method and a temperature controller for controlling the temperature of a T die (flat die) used for forming a sheet or film made of a thermoplastic resin or the like.

As a method of manufacturing a thermoplastic resin film or sheet, there is a wide T-die method in which a molten resin is extruded and discharged from a T-die having a slit-shaped die lip, formed into a film or sheet, and solidified with a cooling roll and taken up. (For example, refer patent document 1).
Japanese Patent No. 3533101

  The T-die has a wide plate shape for forming films and sheets, and the molten resin flowing in from the extruder flows in the width direction through the manifold and is discharged from the slit-shaped die lip at the tip. The

  The temperature of the T die is closely related to the viscosity of the molten resin, and thus the flow of the molten resin. For this reason, the heater and the die are arranged so that the thickness in the width direction of the film or the like discharged from the T die is uniform. A plurality of temperature sensors are installed along the width direction of the T die to control the temperature of the T die.

  However, a flow path such as a manifold is formed in the T die so that the molten resin flowing from the extruder spreads in the width direction uniformly, and a temperature sensor or the like is attached to the die lip portion at the tip. For this reason, it is not preferable to process the mounting holes and the like, so that the installation position of the heater and the temperature sensor is restricted, and the temperature control is performed by installing the heater and the temperature sensor away from the tip die lip.

  For this reason, even if temperature control at a position away from the die lip is normally performed, the temperature distribution of the die lip portion at the tip becomes non-uniform, and the thickness in the width direction of the film or the like discharged from the die lip is reduced. There is a problem of causing variation.

  In addition, since a plurality of heaters and a plurality of temperature sensors are installed in the width direction of the T die and temperature control is performed, that is, so-called multiple channel temperature control, the amount of heat generated by a heater of a certain channel is changed. Further, there is an issue that interference between adjacent channels changes, and stable temperature control is not easy.

  The present invention has been made in view of the above points, and an object of the present invention is to improve the accuracy of temperature control of a die lip portion at the tip of a die.

(1) The die temperature control method of the present invention is a method for controlling the temperature of a die that is provided with a heater and that discharges molten resin from the die lip. Is used to control the die temperature.

  According to the die temperature control method of the present invention, the temperature of the die is controlled by detecting the temperature of the die near the die lip or the resin near the die lip, so the temperature of the die is detected by detecting the temperature at a position away from the die lip. Compared to the conventional example, the accuracy of temperature control in the vicinity of the die lip can be increased, and thereby the variation in the thickness of the film-like or sheet-like resin discharged from the die lip can be reduced.

  (2) In one embodiment of the die temperature control method of the present invention, the temperature of the die near the die lip is detected by a temperature sensor detachably attached to the die lip in the vicinity of the die lip.

  According to this embodiment, the temperature in the vicinity of the die lip can be easily attached to the existing die without applying processing for forming a mounting hole for attaching the temperature sensor in the vicinity of the die lip. Can be detected.

  As another embodiment, instead of heat-resistant tape, a heat-resistant adhesive or the like may be used to attach or detach, or the existing screw holes provided on the die may be used for attachment / detachment. It may be possible to attach it, and it is preferable that the die is detachably attached without any special processing.

  (3) In another embodiment of the die temperature control method of the present invention, the temperature of the resin discharged from the die lip is detected by a radiation thermometer.

  According to this embodiment, the temperature of the resin near the die lip can be detected in a non-contact manner without installing a contact-type temperature sensor near the die lip.

 (4) According to the die temperature control method of the present invention, a plurality of heaters and a plurality of heater temperature detection sensors for detecting the temperature in the vicinity of each heater are disposed, and the temperature of the die that discharges molten resin from the die lip. A plurality of die lip temperature detection sensors are disposed in the vicinity of the die lip, based on a detected temperature in the vicinity of the heater detected by the heater temperature detection sensor and a target temperature in the vicinity of the heater. Based on the secondary loop for determining the control output for the heater, the detected temperature in the vicinity of the die lip detected by the sensor for detecting the die lip temperature, and the target temperature for the vicinity of the die lip, The main loop for determining the target temperature is configured to perform cascade control.

  According to the die temperature control method of the present invention, the target temperature for the heater vicinity is determined by the main loop so that the detected temperature in the vicinity of the die lip matches the target temperature for the die lip vicinity. Since the heater is controlled so that the detected temperature matches the target temperature for the heater vicinity determined by the main loop, it becomes possible to control the detected temperature near the die lip to the target temperature for the die lip, Compared to the conventional example that controls the temperature of the die by detecting the temperature at a position away from the die lip, the temperature in the vicinity of the die lip can be controlled more accurately, and as a result, a film-like or sheet-like resin discharged from the die lip Variation in thickness can be reduced.

  (5) In one embodiment of the die temperature control method of the present invention, the die lip temperature detection sensor is detachably attached to the vicinity of the die lip with a heat-resistant tape.

  According to this embodiment, the temperature in the vicinity of the die lip can be easily attached to the existing die without applying processing for forming a mounting hole for attaching the temperature sensor in the vicinity of the die lip. Can be detected.

  (6) In the embodiment of the above (5), an adjustment step of performing the cascade control for each molding condition of the resin to determine a target temperature for the vicinity of the heater and storing it in a storage means; and the die lip temperature An operation step of removing the detection sensor and performing temperature control only by the sub-loop using the stored target temperature in the vicinity of the heater.

  According to this embodiment, in the adjustment step, a heater for performing cascade control for each molding condition such as resin type and resin feed rate so that the detected temperature near the die lip coincides with the target temperature near the die lip. The target temperature for the vicinity is determined and stored in the storage means. In the subsequent operation process, the die lip temperature detection sensor is removed, and the heater at a position away from the die lip and the heater temperature detection sensor are used as in the past. Thus, the temperature in the vicinity of the die lip can be controlled by controlling the temperature only by the sub-loop so that the detected temperature in the vicinity of the heater matches the stored target temperature in the vicinity of the heater.

  (7) In another embodiment of the die temperature control method of the present invention, the controller of at least one of the main loop and the sub-loop uses a plurality of detection temperatures of the temperature detection sensor as a plurality of detection temperatures. The gradient temperature and the representative representative temperature are converted into the representative temperature, and the gradient temperature and the representative temperature are controlled as control amounts.

  The representative temperature refers to a temperature that typically represents the temperature of the detection target, such as an average temperature of the detection target, a temperature at a certain position (for example, a central position), or the like.

  The gradient temperature refers to a temperature gradient, that is, a temperature difference.

  According to this embodiment, gradient temperature control is performed in which the gradient temperature and the representative temperature are controlled as control amounts, so that interference can be suppressed and the temperature near the die lip can be uniformly controlled as will be described later.

  (8) In another embodiment of the die temperature control method of the present invention, the die is a T-die.

  According to this embodiment, the temperature in the vicinity of the die lip of the T die that is long in the width direction can be accurately controlled, and variations in the thickness direction of the film-like or sheet-like resin discharged from the die lip can be reduced.

  (9) The temperature controller of the present invention is provided with a plurality of heaters and a plurality of heater temperature detection sensors for detecting the temperature in the vicinity of each heater, and controls the temperature of the die that discharges the molten resin from the die lip. And a target temperature for the vicinity of the heater so that the detected temperature near the die lip detected by the sensor for detecting the die lip disposed in the vicinity of the die lip becomes the target temperature for the vicinity of the die lip. A main controller to determine, and a sub-controller to determine a control output for the heater so that a detected temperature in the vicinity of the heater detected by the heater temperature detection sensor becomes a target temperature in the vicinity of the heater from the main controller At least one of the controllers.

  When the temperature controller includes only the main controller or only the sub controller, it is preferable to perform cascade control by connecting two temperature controllers each including each controller.

  According to the temperature controller of the present invention, the target temperature near the heater is determined by the main controller so that the detected temperature near the die lip matches the target temperature near the die lip, and the sub controller detects the vicinity of the heater. Cascade control is performed to control the heater so that the temperature matches the target temperature near the heater determined by the main loop, so that the detected temperature near the die lip can be controlled to the target temperature near the die lip. Compared to the conventional example in which the temperature at the position away from the die lip is detected to control the temperature of the die, the temperature near the die lip can be controlled with high accuracy. Variation in the thickness of the resin can be reduced.

  (10) In one embodiment of the temperature controller of the present invention, the controller includes a sub-controller of the controllers, and storage means for storing the target temperature for the vicinity of the heater determined by the main controller. The sub-controller determines a control output for the heater so that the detected temperature in the vicinity of the heater detected by the heater temperature detection sensor becomes the target temperature for the vicinity of the heater stored in the storage means. It is.

  The target temperature in the vicinity of the heater determined by the main controller is preferably determined for each molding condition such as the type of resin and the feed rate of the resin, and is preferably stored in the storage means for each molding condition.

  According to this embodiment, after the main controller determines the target temperature near the heater for matching the temperature near the die lip with the target temperature near the die lip and stores it in the storage means, the die lip temperature detection sensor is As before, using the heater and heater temperature detection sensor at a position away from the die lip, the temperature only by the sub-controller is set so that the detected temperature near the heater matches the stored target temperature near the heater. By performing the control, the temperature near the die lip can be controlled.

  According to the present invention, the temperature of the die or the resin in the vicinity of the die lip is detected to control the temperature of the die. Therefore, compared with the conventional example in which the temperature at a position away from the die lip is detected to control the temperature of the die. The accuracy of temperature control in the vicinity can be increased, and thereby the variation in the thickness of the film-like or sheet-like resin discharged from the die lip can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram of a film manufacturing apparatus according to one embodiment of the present invention, and FIG. 2 is a diagram showing a T die viewed from the direction of arrow A in FIG.

  The molten resin melted and extruded by the extruder 1 is supplied to the T-die 2 through the supply path 20, spread in the width direction (left-right direction in FIG. 2) by the manifold 3, and the slit-shaped die lip 4 at the tip. As shown in FIG. 1, the discharged film 5 is cooled on both the front and back surfaces by a pair of cooling rollers 6 and 7, and is wound on a winder 10 through subsequent rolls 8 and 9. It is done.

  FIG. 3 is a diagram showing the arrangement of the heaters and temperature sensors of the T-die 2 of this embodiment, and corresponds to FIG.

  A plurality of temperature sensors 12 such as three heaters 11 and three thermocouples are arranged in the T-die 2 along the width direction (longitudinal direction of the T-die). Temperature control is performed. The heater 11 and the temperature sensor 12 are respectively attached to attachment holes (not shown) at positions away from the die lip 4 at the tip of the T die 2 as in the conventional case.

  Thus, conventionally, since the heater 11 and the temperature sensor 12 are arranged at a position away from the die lip 4 at the tip to control the temperature, even if the temperature control is normal, The temperature distribution in the portion of the die lip 4 becomes non-uniform so that the thickness in the width direction of the film 5 varies.

  Therefore, in order to reduce the thickness variation, the die temperature control method of this embodiment includes an adjustment step and an operation step. In the adjustment step, each heater is placed in the vicinity of the die lip 4 of the T die 2 in advance. 11, three temperature sensors 13 are detachably attached using, for example, a heat-resistant tape (not shown), and cascade control is performed as described later to uniformly control the temperature distribution in the vicinity of the die lip 4. An appropriate target temperature is determined for each molding condition such as the type of film and the film feed speed, and in the subsequent operation process, the temperature sensor 13 near the die lip 4 is removed and determined in advance for each molding condition. The same control as before is performed so that the target temperature is reached.

  FIG. 4 is a block diagram showing a configuration of cascade control performed for obtaining in advance the target temperature for uniformly controlling the temperature in the vicinity of the die lip 4 for each adjustment step, that is, for each molding condition.

  In the temperature controller of this embodiment, during cascade control, the operation amount is controlled based on the detected temperature PVm from the temperature sensor 13 that detects the temperature in the vicinity of the die lip 4 and the target temperature SPm in the vicinity of the die lip. (Sub-controller) Primary loop controller (main controller) 14 given as a target temperature SPs in the vicinity of the heater 15, detection temperature PVs of the temperature sensor 12 detecting the temperature in the vicinity of the heater 11 of the T die 2, and the primary loop controller 14 And the secondary loop controller 15 that provides a control output MV for controlling the energization of the heater 11 of the T die 2 based on the target temperature SPs for the vicinity of the heater. The primary loop controller 14 and the secondary loop controller 15 are configured by, for example, a microcomputer.

  In this embodiment, the primary loop controller 14 and the secondary loop controller 15 are previously proposed by the present applicant as, for example, Japanese Patent No. 3278807, in order to reduce the influence of interference by the heaters 11 of adjacent channels. Control method, that is, a plurality of detected temperatures corresponding to a plurality of control points are converted into a representative temperature, for example, an average temperature of the plurality of detected temperatures, and a gradient temperature that is a temperature difference based on the plurality of detected temperatures. And a method of controlling the temperature using the average temperature and the gradient temperature as control amounts (hereinafter also referred to as “gradient temperature control”).

  FIG. 5 is a block diagram of the primary loop controller 14.

  The primary loop controller 14 converts the three detected temperatures PVm from the temperature sensor 13 that detects the temperature in the vicinity of the die lip of the T die 2 into one representative temperature and two gradient temperatures according to the following mode conversion matrix Gm. 1 mode conversion unit 16, a second mode conversion unit 21 that converts three target temperatures SPm near the die lip into one target representative temperature and two target gradient temperatures according to the mode conversion matrix Gm, and both modes Based on the deviation between each temperature from the conversion units 16 and 21 and each target temperature, the three PID control units 17 to 19 for PID calculation and the operation amounts from the PID control units 17 to 19 are distributed as described later. The distribution is performed according to the pre-compensation matrix Gc that is a ratio matrix, and the effect of the control by each PID control unit on the control by other PID control units The eliminating or distributed to as small, and a pre-corrector 20 to give a set temperature SPs for secondary loop controller 15.

  Each mode conversion unit 16, 21 performs conversion according to the following mode conversion matrix Gm that converts the three temperatures PVm, SPm into one representative temperature and two gradient temperatures, respectively.

すなわち、３つの温度を、３つの温度の平均温度である１つの代表温度と、隣接する検出点の温度差である２つの傾斜温度とに変換する。

That is, the three temperatures are converted into one representative temperature that is an average temperature of the three temperatures and two gradient temperatures that are temperature differences between adjacent detection points.

  In this gradient temperature control, the PID control unit 17 among the three PID control units 17 to 19 calculates an operation amount based on a deviation between the representative temperature (average temperature) and the target representative temperature (target average temperature). The PID control unit for the representative temperature is used, and the PID control units 18 and 19 are the PID control unit for the gradient temperature that calculates the operation amount based on the deviation between the gradient temperature and the target gradient temperature.

  In this embodiment, the target tilt temperature is controlled to be a uniform temperature, and is thus converted to “0 ° C.”.

  Determination of the PID constants of the PID control units 17 to 19 and the prefix that is a matrix of the distribution ratio of how the operation amount from each PID control unit 17 to 19 is distributed to each channel by the precompensation unit 20 The determination of the compensation matrix Gc will be described later.

  FIG. 6 is a block diagram of the secondary loop controller 15.

  The secondary loop controller 15 converts the three detected temperatures PVs from the temperature sensor 12 that detects the temperature in the vicinity of the heater 11 of the T die 2 into one average temperature and two gradient temperatures according to the mode conversion matrix Gm. The third mode converter 22 and the fourth mode converter 23 that converts the three target temperatures SPs from the primary loop controller 14 into one target average temperature and two target gradient temperatures according to the mode conversion matrix Gm. And, based on the deviations between the temperatures from the mode conversion units 22 and 23 and the target temperatures, the three PID control units 24 to 26 that perform PID calculation, and the operation amounts from the PID control units 24 to 26, respectively. The distribution is performed according to a pre-compensation matrix Gc which is a matrix of a distribution ratio described later, and control by each PID control unit is performed by other PID control units. And a predistortion unit 27 before giving control output MV to the heater 11 and distributed so that the influence to eliminate or reduce the give us to.

  Here, the distribution ratio of how the operation amount is distributed to each channel by the determination of the PID constants of the PID control units 17 to 19 and 24 to 6 of the controllers 14 and 15 and the precompensation units 20 and 27. The determination of the pre-compensation matrix Gc that is a matrix of will be described.

  First, the primary loop controller 14 is stopped, and the PID constant and the pre-compensation matrix of the secondary loop controller 15 are performed by the same auto-tuning of the gradient temperature control as in the prior art.

  For example, as described in Japanese Patent Application Laid-Open No. 200-265447, the gradient temperature control auto-tuning is performed with stepwise operation amounts MV1 to MV3 of 100% for each channel, as shown in FIGS. As shown in (c), the step response waveforms PV1 to PV3 of each channel shown in FIGS. 7D to 7F are measured in order, and the dead time and the maximum inclination of each channel are measured. The temperature rise value ΔPV is measured.

  The degree of interference of each channel is measured based on the temperature change ΔPV of each channel corresponding to this stepwise manipulated variable input, and the amount of manipulated variable distribution in the pre-compensation unit 17 based on the degree of interference. The pre-compensation matrix Gc, which is a matrix of

Specifically, as disclosed in the above publication, Gp is a matrix indicating the degree of interference of the control target obtained by measuring the temperature change ΔPV of the step response waveform of each channel, and the above-described mode conversion matrix is Assuming Gm, the pre-compensation matrix Gc of the pre-compensation unit 27 is
Gc = (Gm · Gp) ⁻¹
Can be obtained as

  Further, the PID constants of the PID control units 24 to 26 are calculated by the Ziegler & Nichols method from the dead time L and the maximum slope R of the step response waveform typically shown in FIG.

  After the auto-tuning of the gradient temperature control of the secondary loop controller 15 is completed as described above, the tuned secondary loop controller 15 is put into an operating state, and the auto-tuning of the gradient temperature control is similarly performed for the primary loop controller 14. Then, the PID constants of the PID control units 17 to 19 of the primary loop controller 14 and the pre-compensation matrix of the pre-compensation unit 20 are determined.

  In this embodiment, the primary loop controller 14 converts the detected temperature PVm in the vicinity of the die lip 4 into a gradient temperature that is a temperature difference between the average temperature and the detected temperature of the adjacent channel, and the average temperature and the gradient temperature are the target average. The operation amount is calculated so as to match the temperature and the target gradient temperature, and is distributed as the target temperature SPs for each channel.

  The secondary loop controller 15 converts the detected temperature PVs in the vicinity of the heater 11 into an average temperature and a gradient temperature, and matches the target average temperature and the target gradient temperature based on the target temperature SPs from the primary loop controller 14. The operation amount is calculated and distributed as the operation amount (control output) for the heater 11 of each channel.

  Thus, cascade control is performed so that the temperature in the vicinity of the die lip 4 becomes the target temperature SPm for the vicinity of the die lip.

  This cascade control is performed for each molding condition such as the type of thermoplastic resin and the feed rate of the thermoplastic resin, and the vicinity of the heater with respect to the secondary loop controller 15 for setting the temperature in the vicinity of the die lip 4 to the target temperature SPm for the vicinity of the die lip. Target temperature SPs, that is, the output of the primary loop controller 14 is obtained. Then, the heater target temperature SPs, which is the output of the primary loop controller when the temperature PVm near the die lip 4 is stabilized at the target temperature SPm near the die lip, is stored in a bank as a storage means.

  FIG. 9 is a block diagram showing a configuration in a normal operation process after storing the heater vicinity target temperature SPs for the secondary loop controller 15 in the bank through the above adjustment process.

  In this operation process, the temperature sensor 13 for detecting the temperature in the vicinity of the die lip 4 is removed, the temperature in the vicinity of the heater 11 of the T die 2 is detected by the temperature sensor 12, and the detected temperature PVs and the cascade control are obtained. The gradient temperature control is performed by the secondary loop controller 15 based on the target temperature SPs near the heater from the target temperature bank 28 in which the target temperature SPs near the heater is stored for each molding condition.

  In the target temperature bank 28, the target temperature SPs for the vicinity of the heater for uniformly controlling the temperature in the vicinity of the die lip 4 is stored in advance as described above. Therefore, the gradient temperature control is performed so that the target temperature SPs becomes the target temperature SPs. By performing the above, the vicinity of the die lip 4 can be controlled to a uniform temperature without detecting the temperature near the die lip 4.

  FIG. 10 is a flowchart showing the procedure of the above-described die temperature control method.

  In this embodiment, first, the temperature sensor 13 described above is installed near the die lip 4 of the T die 2 with heat-resistant tape or the like (step n1), and cascade control is performed for each molding condition (step n2). The target temperature for the heater vicinity of the secondary loop is stored in the bank 28 for each molding condition (step n3). These steps n1 to n3 are the adjustment process described above.

  Next, in the operation process, it is determined whether a new molding condition has occurred or has changed over time (step n4), and when a new molding condition has occurred or has changed over time, the process returns to step n1. .

  When no new molding condition has occurred and the aging has not changed, only the secondary loop is controlled using the target temperature SPs for the vicinity of the heater stored in the bank 28 (step n5).

  As described above, in the adjustment process, cascade control is performed to obtain the heater vicinity target temperature SPs for uniformly controlling the temperature in the vicinity of the die lip 4 and store it in the bank 28. In the operation process, in the vicinity of the heater. The detected temperature PVs is controlled to be the target temperature SPs for the vicinity of the heater stored in the bank 28, so that the temperature at a position away from the die lip 4 is detected to control the die temperature. Thus, the temperature in the vicinity of the die lip can be controlled with high accuracy, thereby reducing variations in the thickness direction of the film or sheet discharged from the die lip.

  In cascade control for obtaining the target temperature for the secondary loop controller 15, the temperature sensor 13 is detachably attached to the vicinity of the die lip 4 with heat-resistant tape. The present invention can be easily applied without processing.

(Other embodiments)
In the above-described embodiment, the temperature sensor 13 is attached in the vicinity of the die lip 4 to detect the temperature. However, as another embodiment of the present invention, as shown in FIG. The temperature at each of the five measurement points 29 may be detected by a radiation thermometer (not shown) or the like and cascade controlled.

  In the above-described embodiment, the loop controllers 14 and 15 perform the gradient temperature control. However, as another embodiment of the present invention, at least one of the loop controllers 14 and 15 replaces the gradient temperature control for each channel. Individual PID control may be performed.

  In the above-described embodiment, cascade control is performed to obtain the target temperature for the secondary loop controller 15 and the result is stored in the storage means. Thereafter, only the secondary loop controller 15 is controlled. As a form, the temperature in the vicinity of the die lip 4 may always be detected to perform cascade control. In this case, the T die 2 is processed to provide a temperature sensor mounting hole and the like, and a temperature sensor for detecting the temperature in the vicinity of the die lip 4 is attached to the mounting hole and the temperature of the T die 2 near the die lip 4 is adjusted. You may make it always detectable.

     Further, the temperature near the die lip 4 may be constantly detected without performing cascade control, and the detected temperature near the die lip may be controlled to be the target temperature near the die lip.

  Although the temperature controller of the above-described embodiment includes the primary loop controller 14 and the secondary loop controller 15, as another embodiment of the present invention, the temperature controller is configured to include either one of the controllers. In this case, the temperature controller including the primary loop controller 14 and the temperature controller including the secondary loop controller 15 are communicably connected to perform the cascade control described above, and the obtained heater The target temperature for the vicinity may be stored in the storage means of the temperature controller including the secondary loop controller, and thereafter, control by only the temperature controller including the secondary loop controller may be performed.

  In the above-described embodiment, the present invention is applied to the T die. However, the present invention is not limited to the T die but can be applied to an inflation die.

  The present invention is useful for temperature control of a die used for forming a film, a sheet or the like.

It is a schematic block diagram of the film manufacturing apparatus which concerns on one embodiment of this invention. It is a figure which shows T-die of FIG. It is a figure which shows arrangement | positioning of the heater and temperature sensor of T-die. It is a block diagram which shows the structure of the cascade control in an adjustment process. FIG. 5 is a block diagram of the primary loop controller of FIG. 4. It is a block diagram of the secondary loop controller of FIG. It is a time chart of the operation amount at the time of auto tuning of inclination temperature control, and detected temperature. It is a figure which shows the maximum inclination and dead time of the step response waveform of FIG. It is a block diagram which shows the structure of the temperature control in an operation process. It is a flowchart with which operation | movement description is provided. It is a figure which shows the temperature detection of the T-die of other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Extruder 2 T die 4 Die lip 5 Film 11 Heater 12 Temperature sensor (For heater vicinity temperature detection)
13 Temperature sensor (for detecting temperature near die lip)
14 Primary loop controller (main controller)
15 Secondary loop controller (sub controller)

Claims (10)

A method of controlling the temperature of the die that discharges the molten resin from the die lip while the heater is disposed,
A die temperature control method comprising: detecting a die temperature near a die lip or a resin temperature to control the die temperature.   The die temperature control method according to claim 1, wherein the temperature of the die in the vicinity of the die lip is detected by a temperature sensor detachably attached to the vicinity of the die lip with a heat-resistant tape.   The die temperature control method according to claim 1, wherein the temperature of the resin discharged from the die lip is detected by a radiation thermometer. A plurality of heaters and a plurality of heater temperature detection sensors for detecting the temperature in the vicinity of each heater are disposed, and a method for controlling the temperature of a die that discharges molten resin from a die lip,
A plurality of die lip temperature detection sensors are disposed in the vicinity of the die lip,
A sub-loop that determines a control output for the heater based on a detection temperature in the vicinity of the heater detected by the heater temperature detection sensor and a target temperature in the vicinity of the heater, and a die lip detected by the die lip temperature detection sensor A die temperature characterized by comprising a main loop for determining a target temperature for the heater vicinity for the sub-loop based on a detection temperature in the vicinity and a target temperature for the die lip, and performing cascade control Control method.   The die temperature control method according to claim 4, wherein the die lip temperature detection sensor is detachably attached to the vicinity of the die lip with a heat-resistant tape. For each molding condition of the resin, an adjustment step of performing the cascade control, determining a target temperature for the vicinity of the heater, and storing it in a storage unit;
An operation step of removing the die lip temperature detection sensor and performing temperature control only by the sub-loop using the stored target temperature in the vicinity of the heater,
A temperature control method for a die according to claim 5.   The controller of at least one of the main loop and the sub loop converts a plurality of detected temperatures of the temperature detection sensor into a gradient temperature and a representative representative temperature based on the plurality of detected temperatures, and the gradient temperature and The die temperature control method according to claim 4, wherein the representative temperature is controlled as a control amount.   The die temperature control method according to claim 1, wherein the die is a T die. A plurality of heaters and a plurality of heater temperature detection sensors for detecting the temperature in the vicinity of each heater, and a temperature controller for controlling the temperature of a die that discharges molten resin from a die lip,
A main controller for determining a target temperature for the vicinity of the heater so that a detection temperature in the vicinity of the die lip detected by a die lip temperature detection sensor disposed in the vicinity of the die lip becomes a target temperature for the vicinity of the die lip; and At least one controller of a sub-controller that determines a control output to the heater so that a detected temperature in the vicinity of the heater detected by the heater temperature detection sensor becomes a target temperature in the vicinity of the heater from the main controller. A temperature controller characterized by that. A storage means for storing the target temperature for the vicinity of the heater determined by the main controller, as well as the sub controller of the two controllers;
The sub controller determines a control output to the heater so that a detected temperature in the vicinity of the heater detected by the heater temperature detection sensor becomes a target temperature in the vicinity of the heater stored in the storage unit. 9. The temperature controller according to 9.

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