JPS63104814A - Resin temperature control device for extruder - Google Patents

Abstract

PURPOSE:To enhance safety of control by providing cylinder control blocks equipped with a heater and temperature sensing components and a sensing section of temperature of extruded resin, and utilizing the temperature of a cylinder control block selected optionally as the controlled variable of a resin temperature control loop. CONSTITUTION:A cylinder section 1 is divided into a plurality of cylinder control blocks 3a-3e, and said blocks are equipped with block heaters 4a-4e and temperature sensing components 5a-5e respectively, and at an outlet 1a of the cylinder section 1, a resin temperature sensing section 6 sensing directly the temperature of extruded resin is provided. When a control instruction of resin temperature is issued from a keyboard 13, the block heater 4a-4c are ON, and when the resin temperature is confirmed to have risen up to within starting deviation DELTART, a specified resin tempera ture control loop is selected and a given temperature control loop is formed up. The same judges whether the cylinder temperature after forming the control loop is within the range of given upper and lower limit values, and if not, an alarm for the abnormal situation is issued to an indicating section corresponding to said temperature control loop, or if it is within said range, abnormal output is turned OFF and the cycle is completed.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a resin temperature control device in an extruder.

(Prior Art) Conventionally, as described in, for example, Japanese Unexamined Patent Application Publication No. 49-11952, a heater provided at the tip of the cylinder of an extruder is controlled at different temperatures when the extruder is in operation and when the extruder is at rest. Temperature control methods have been proposed that form control loops. In other words, according to this temperature control method, when the extruder is operating, a temperature control loop is formed based on the temperature value of the extruded resin, and when the extruder is not operating, a temperature control loop is formed based on the temperature value detected at the tip of the cylinder part. are doing.

(Problem to be Solved by the Invention) However, in this type of temperature control method, although the cylinder section is provided with a plurality of heaters, the temperature is controlled only for the heater at the tip of the cylinder outlet. Since a control loop is formed, depending on the structure and characteristics of the extruder, it may be more preferable to form a temperature control loop for other heaters than for the heater at the tip of the cylinder outlet, which increases versatility. There was a problem that there was a lack of

In addition, if a temperature control loop based on the resin temperature value is not formed, the detected temperature will not be detected until a certain period of time has passed after the molten resin passes through the resin temperature due to the influence of the heat capacity of this detection part. Because the resin temperature is lower than the desired temperature,
Immediately after the start of extrusion, the temperature at the tip of the cylindrical part became abnormally high, which sometimes resulted in poor product yield immediately after the start of extrusion.

Further, in the conventional temperature control method, no measures are taken when the control deviation of the temperature control loop for the heater becomes large, so that the temperature of the cylinder section sometimes becomes abnormally high.

(Means for Solving the Problems) The resin temperature control device in the extruder according to the present invention is provided by dividing the cylinder section of the extruder into a plurality of locations along the length direction, and is provided with a heater and a temperature control device. A cylinder control block equipped with a detection body and a resin temperature detection section that directly detects the temperature of the extruded resin are provided, and the temperature detected by the temperature detection body of an arbitrarily selected cylinder control block is the temperature of the resin. This is the control amount of the resin temperature control loop. Further, the resin temperature control loop is formed after the resin temperature detected by the resin temperature detection section falls within a predetermined deviation, and furthermore, the temperature detected by the temperature detection element of the cylinder control block falls within a predetermined upper and lower limit. The configuration is such that it is compared with a threshold value and the comparison result is output to the outside.

(Function) The resin temperature control loop is formed not only for the heater at the end of the outlet of the cylinder section but also for the heater of an arbitrarily selected cylinder control block, and can be changed as appropriate depending on the structure and characteristics of the extruder to make it universal. Give it sex. Further, the resin temperature control loop is formed after the resin temperature detected by the resin temperature detection section falls within a predetermined deviation, thereby reducing the influence of the heat capacity of the resin temperature detection section, and furthermore, the cylinder control loop is formed after the resin temperature detected by the resin temperature detection section is within a predetermined deviation. When the temperature detected by the temperature detector exceeds the predetermined upper and lower thresholds, an external output such as an alarm is issued, improving control safety.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram showing a cylinder section 1 of an extruder.

A main screw 2 is provided within the cylinder portion 1 and is rotationally driven by an extrusion motor (not shown). The cylinder section 1 is divided into a plurality of cylinder control blocks 3a to 3e along the length direction. The cylinder M4Il blocks 3a to 3e each have block heaters 4a to 4e arranged along the outer wall of the cylinder part l,
For example, it includes temperature sensing bodies 5a to 5e that are fitted into the cylinder portion l. The block heaters 4a to 4
Each of e is connected to a relay 73 and a power supply 8a, and this relay 7a is 0N10FF duty-controlled by a control signal output from a digital input/output board 17 based on a command from a CPU/memory board 12, which will be described later. In the drawing, a relay 73 and a power supply 8a are illustrated for the cylinder control block 3a, but relays 7b to 7e are also provided for the other cylinder control blocks 3b to 3e.

Chip-shaped molding material introduced into the cylinder portion 1 from a raw material hopper (not shown) is melted at a predetermined temperature and extruded by the operation of the block heaters 4a to 4e. Further, a resin temperature detection section 6 that directly detects the extruded resin temperature YR is provided at the outlet 1a of the cylinder section 1, and the resin temperature YII detected by the resin temperature detection section 6 is set to a preset value. It is controlled to be R(1).

FIG. 2 shows a block diagram of a resin temperature control device according to the present invention.

In FIG. 2, the set value R (R) is changed by switching the software switches 10a to 10e to the PID calculation units 9a to 10e.
9e, and based on the calculation results, PID calculation control is performed to control the block heaters 4a to 4e of the cylinder control blocks 33 to 3e. The temperatures YC and -YcS detected by the temperature detectors 5a to 5e of each cylinder control block 3a to 3e are added and the cylinder process 11
make it work. What is obtained by the operation of this cylinder process 11 is the resin temperature Yll. This resin temperature Y is subtracted from the set value R (11) to obtain the resin temperature deviation.
One of the software switches 10e to 10e (software switch 10b in the drawing) is switched from terminal a to the terminal side according to a switching instruction from the CPU/memory board 12, and the temperature detected by each temperature detector 5a to 5e is R
A resin temperature control loop is formed with CI to Rcs as control variables.

When this resin temperature control loop is formed, this loop performs PID calculation using the resin temperature deviation as input, and outputs a control signal from the digital input/output board 17 to the selected block heaters 4a to 4e. Note that this resin temperature control loop is designated when the resin temperature detected by the resin temperature detection section 6 falls within a predetermined starting deviation ΔRT. Further, the temperature values detected by the temperature detectors 5a to 5e of each cylinder control block 3a to 3e are compared with predetermined upper and lower thresholds, and when the temperature values are outside the range of the upper and lower thresholds, the digital input/output board 17 An alarm will be output.

FIG. 3 shows a case where the hardware of the resin temperature control device in the extruder according to the present invention is constituted by various basic boards.

The CPU/memory board 12 is a board that plays a central role in controlling various input/output interface circuits, and has a built-in resin temperature control program.
It houses LSIs such as key controllers. This C
The PU/memory board 12 controls a keyboard 13 equipped with various keys and a CRT display 14, as well as an analog input board 16 that inputs analog signals and a digital input/output board that inputs and outputs digital signals via the motherboard 15. It controls 17. The set value of the resin temperature and the value of the starting deviation ΔRT are set and input using the keyboard 13. Further, the temperature detection bodies 5a to 5
e and the temperature detected by the resin temperature detection section 6 are input from the analog input board 16. Furthermore, from this digital input/output board 17, the block heaters 4a to
A control signal for controlling the 0N10FF of 4e and an alarm signal are output when the values detected by the temperature detectors 5a to 5e exceed a predetermined upper and lower threshold range.

FIG. 4 is a flowchart showing the control procedure of the resin temperature control program built into the CPU/memory board 12. This flowchart exemplifies the case where one resin temperature control loop is formed.

When the resin temperature control command is operated from the keyboard 13 in step (2), the cylinder control blocks 3a to 3
The block heaters 4a to 4e of e are respectively turned on.

When it is confirmed that the resin temperature has risen to within the starting deviation ΔRT (step knob ■), the designated resin temperature control loop is selected in step ■, and a predetermined resin temperature control loop is formed in step ■. do. In step (2), it is determined whether the cylinder temperature after the control loop is formed is within the predetermined upper and lower thresholds, and if it is not, an alarm is issued on the display section (not shown) corresponding to the temperature control loop. Notify of abnormality (step ■).

If it is within the range of the upper and lower thresholds, the abnormal output is turned off and the process ends (step ■). Furthermore, if there is no resin temperature control command in step (2) and if the resin temperature does not fall within the starting deviation ΔRT in step (2), the resin temperature control loop is canceled and the process ends in step (2).

In addition, in the above-mentioned embodiment, the case where the number of cylinder control blocks is five is illustrated, but of course the number is not limited to this. More than one may be formed at the same time.The combination of these may be arbitrarily determined by the temperature control program.

Note that the upper and lower thresholds are determined by each cylinder control block 3a to
The same value or different values may be set for 3e.

(Effects of the Invention) As described above, according to the present invention, since the resin temperature control loop can be arbitrarily selected, it can be universally adapted to the structure and characteristics of the extruder. Furthermore, since the resin temperature control loop is not formed until the resin temperature falls within a predetermined starting deviation, detection errors due to the heat capacity of the resin temperature detection section can be reduced. Furthermore, since upper and lower thresholds are provided for each cylinder control block, control safety is improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the cylinder section of an extruder, Fig. 2 is a block diagram illustrating the resin temperature control loop in the resin temperature control device according to the present invention, and Fig. 3 shows the hardware configured by various basic boards. A block diagram showing the case where
FIG. 4 is a flowchart showing the flow of the resin temperature control program. 1... Cylinder parts 3a to 3e... Cylinder control blocks 42 to 4e...
・Block heaters 5a to 5e...Temperature detectors 108 to 10e...Software switch Patent applicant Representative of Sekisui Chemical Co., Ltd. Hiroshi 1) Kaoru Figure 1 1 ¥ 2 Figure 13

Claims (1)

[Claims] 1) The cylinder section of the extruder is divided into a plurality of sections along the length, and includes a cylinder control block equipped with a heater and a temperature sensor, and a cylinder control block equipped with a heater and a temperature sensor, and A resin temperature detection section that directly detects the temperature is provided, and the temperature detected by the temperature detection element of the arbitrarily selected cylinder control block is used as the control amount of the resin temperature control loop that controls the resin temperature. Resin temperature control device for extruder. 2) The resin temperature control device for an extruder according to claim 1, wherein the resin temperature control loop is formed after the resin temperature detected by the resin temperature detection section falls within a predetermined deviation. 3) The resin temperature control device for an extruder according to claim 1, wherein the temperature detected by the temperature detector of the cylinder control block is compared with predetermined upper and lower thresholds, and the comparison result is outputted to the outside.