JPS6049914A - Simulator for pressure control system - Google Patents

Abstract

PURPOSE:To easily confirm whether or not the pressure control function of a process controller works normally by sending a simulator output signal corresponding to pressure to the process controller for pressure control, provided to molding and processing machines for metals, resins, etc. CONSTITUTION:A simulator 70 consists of an adding and reducing machine 72, a rectifier 74, an amplifier 76 and a voltage-current converter 78, including an electric circuit 52 to synthesize the output of the pressure control system of a processor on the basis of drive output command signals for processor, derived from a process controller to control the molding process of the processor. By introducing the synthesized output signals of the pressure control system into the process controller 48, whether or not the pressure control function of the process controller 48 is normal is confirmed. Since the pressure signals of resin in an extruder can be obtained by the simulator 70, whether the control system of the pressure of resin in the controller 48 is normal can be easily checked without the needs to drive the actual extruder when testing or adjusting the process controller 48.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a simulator, and more specifically to a process controller that controls the molding process in a processing machine that heats and melts raw materials such as metal thermoplastic resins and molds them into a certain shape. On the other hand, the present invention relates to a pressure control system simulator for providing a signal corresponding to the pressure of the raw material to be molded and processing, and for checking whether the pressure control function of the process controller is sufficiently exerted.

In an extruder, an injection molding machine, or the like, a heating device attached thereto melts a belent-like thermoplastic resin and molds it into a desired shape under a predetermined pressure. It can be said that controlling the resin pressure during the operation of an extruder, etc. in this manner is essential in order to obtain molded products of uniform quality and also to prevent defective molded products from being produced. In reality, the resin pressure is detected by a pressure sensor such as a strain gauge, and this detection signal is introduced to the process controller 1-roller to control the drive system of the feeder screw, main screw, etc. to achieve the desired purpose. Achieved.

By the way, the resin pressure signal introduced into the process controller as described above can only be obtained by actually installing a pressure sensor in an extruder or the like. Therefore, if the extruder equipped with the pressure sensor is not actually driven during testing or adjustment at the time of shipment from the factory or delivery to the customer, the resin pressure control system of the process controller that controls the molding process may not work properly. It was extremely inconvenient as it was impossible to determine whether it was functioning or not. In addition, there are cases where a continuous function test of the process controller is carried out by attaching a sensor for convenience, but this is only an open-loop confirmation method that is possible as long as pressure is detected, and the pressure detection signal is used to test the process controller's function. It has not been possible to control the output signal of the resin pressure control system.

Therefore, as a result of repeated studies, the present inventors focused on the fact that in extruders and the like that gradually transport thermoplastic synthetic resin through the rotation of a screw, the resin pressure generally increases as the screw rotation speed increases. However, by preparing an electric circuit capable of supplying a voltage corresponding to the screw rotation speed, that is, a voltage corresponding to the strain gauge, and configuring the output to be introduced to the process controller 1-roller, the resin pressure control system of the process controller can be controlled. It was found that it was easy to check whether the function was working properly.

Therefore, the present invention provides a simulator output signal corresponding to the pressure to a process controller that is attached to a processing machine that heats and melts raw materials such as metal thermoplastic synthetic resin and molds them into a fixed shape and controls the pressure. It is an object of the present invention to provide a pressure control system simulator for easily confirming whether the pressure control function of the controller works normally.

In order to achieve the above object, the present invention is attached to a processing machine that melts metal, resin, etc. and molds it into a predetermined shape, and is connected to a process controller that controls the molding process of the processing machine, and is connected to a process controller that controls the molding process of the processing machine. It includes an electric circuit that synthesizes the pressure control system output of the processing machine based on the drive output command signal for the processing machine derived from the controller, and the process is controlled by introducing the synthesized pressure control system output signal into the process controller. The present invention is characterized in that it is configured to confirm whether or not the pressure control function of the controller is available.

Next, the pressure control system simulator according to the present invention will be described in detail below with reference to the accompanying drawings, citing preferred embodiments in relation to the extruder to which it is attached.

Therefore, the relationship between a conventional extruder and its process controller is shown in FIGS. 1 to 3.

FIG. 1 shows a so-called single-screw extruder unit (SE machine), and in the figure, reference numeral 1o indicates the extruder main body,
This extruder main body 1o basically consists of a cylinder part 14 that heats and plasticizes thermoplastic resin and continuously extrudes it to the die 12 side.
and a feeder section 16 for feeding thermoplastic synthetic resin as a raw material to the cylinder section 14. In the feeder portion 16, a feeder screw 2o is rotatably supported inside a barrel 18 constituting the feeder portion 16, and a bomber 22 is disposed with a portion thereof opened. Note that the rotational drive shaft 24 of the screw 2o is connected to the barrel 1.
8 protrudes from one end and is connected to the rotation shaft of the feeder motor 26.

On the other hand, the other bent end of the barrel 18 is connected to the opening 28 of the silling portion 14 . That is, cylinder part 1
The other bent end of the nozzle 18 is connected to an opening 28 passing through the barrel 30 and the lining 32 forming the nozzle 4. A heater 34 for heating the barrel 30 is wound around the peripheral wall of the barrel 30, and a main screw 36 is rotatably supported adjacent to the inside of the peripheral wall of the lining 32. . Lord Skriko, -
The rotating shaft 38 of 36 protrudes from the tail end of the cylinder portion 14 and is connected to the rotating shaft of the screw motor 40 . A filter 42 is disposed in front of the main screw 36, and a cover 2 is mounted further in front of the filter 42.

The feeder motor 26 is connected to a feeder motor driver 44, while the main screw motor 40 is connected to a main screw motor driver 46. The feeder motor dryer 44 and the main screw motor driver 46 are energized by a feeder morph output command signal and a main screw motor output command signal from the process controller 48, respectively. , these output command signals are controlled by pressure detection signals from a pressure sensor (strain gauge) 50 attached to the front of the filter 42. In addition, reference number 5 in the figure
2 is a high-power circuit including a switch circuit for starting the extruder.

Next, FIG. 2 shows a single screw extruder with a gear pump. In this case, the same reference numerals as those in FIG. 1 indicate the same components.

Therefore, in this single-screw extruder with a gear pump, a gear pump 54 is especially installed between the pressure sensor 50 and the die 12,
This gear pump 54 is configured to be rotated by a gear pump motor 56. In addition, in FIG. 2, reference numeral 58 is
This is a motor driver that receives an output command signal from the process controller 48 and urges the gear pump motor 56 to rotate.

Furthermore, FIG. 3 shows a tandem single screw extruder.

In this case as well, the same reference numerals as those in FIG. 1 indicate the same components.

As can be understood from the figure, this tandem single-screw extruder further includes a second cylinder section 60 between the die 12 and the discharge side of the filter 42.

Therefore, the rotating shaft 62 of the main screw protruding from the shipper section 60 is connected to the rotating shaft of the main screw motor 64, and the main screw motor 64 receives an output command signal from the process controller 48 which is sent to the mode driver 66. energized by.

Therefore, the operation of the single screw extruder configured as above will be explained.

First, in the embodiment shown in FIG. 1, after filling the extruder 100 homper 22 with pelletized thermoplastic synthetic resin raw material, if the extruder 10 is started via the high-voltage circuit 52, the process controller 48 The feeder motor drive unit 44 is energized by the output command signal, and the feeder motor 26 rotates accordingly. As a result, the resin raw material is transported forward via the feeder screw 20 and falls into the cylinder section 14 from the opening 28.

At this time, the main screw motor 40 is also rotationally driven under the bias of the main screw motor drive unit 46, so that the raw material is gradually conveyed forward in the same manner. During this time, the heater 34 is energized, and therefore,
The raw material is heated and melted, and is forcibly conveyed from the filter 42 toward the die 12 while being pressed. As can be understood from the figure, the outlet port of the die 12 is considerably constricted, so the increased resin pressure is detected by the pressure sensor 50 and sent to the process controller 48. The process controller 48 controls the output command signal to the feeder motor drive unit 44 and the output command signal to the main screw motor drive unit 46 using the resin pressure signal to obtain an optimum molding process.

By the way, as can be understood from the above description of the operation, in a single-screw extruder, the pressure of the resin being conveyed increases as the number of rotations of the main screw increases. On the other hand, although the rotational speed of the feeder screw 20 has relatively little influence on the detected resin pressure, if the rotational speed of the feeder screw 20 increases, the resin pressure also increases. That is, the rotation command of the feeder screw 20 has a small gain, but works as an additive factor for the resin pressure detected in conjunction with the rotation command signal of the main screw 36.

Next, a single screw extruder equipped with a gear pump, i.e.
The operation of the axle extruder with gear pump shown in FIG. 2 will be explained. This operation is also substantially the same as that of the extruder shown in the first embodiment. However, in this embodiment, the gear pump drive unit 5 from the process controller 48
The output command signal to 8 acts as a subtraction factor. That is, when an output command signal is sent from the process controller 48 to the gear pump drive unit 58, the gear pump 54 forcibly moves the molten resin to the die 12 via the filter 42. Therefore, the resin pressure detected by the pressure sensor 50 is reduced by that amount compared to when the gear pump 54 is not energized.

Furthermore, the operation of a tandem single-screw extruder (see FIG. 3) in which single-screw extruders are arranged in tandem will be explained. The operation of this single-screw extruder is substantially the same as that of a single-screw extruder with a gear pump, especially in terms of resin pressure detection. In other words, the output command signal for the feeder screw 20 and the output command signal for the main screw 36 are added together as an additive factor.Meanwhile, the main screw motor drive unit d6 is energized by the output command signal from the process controller 48, As a result, when the main screw in the second cylinder part 60 rotates, the resin raw material of the melting method sent out through the filter 42 is further forcibly sent out in the direction of the die 12 by the main screw. ,
The resin pressure detected by the resin pressure sensor 50 disposed between the filter 42 and the second cylinder 60 is detected without any residual force being forcibly sent out by the second cylinder section 60. That is, the output command signal of the second cylinder section 60 functions as a subtraction factor here.

Therefore, in the present invention, in particular, the resin pressure sensor 50
Instead, a resin pressure simulator is used, and this output signal is introduced into the process controller 48 to make it possible to check whether the control system related to resin pressure detection of the controller 48 is functioning sufficiently. FIG. 4 shows an example thereof.

The simulator 70 is configured as follows.

That is, a rectifier 74 is connected to the output side of the adder/subtractor 72, and an amplifier 76 is connected to the output side of the rectifier 74. The output side of the amplifier 76 is directly connected to the process controller 48 on one side, but is branched off and connected to the voltage-current converter 78 on the other side, and the output side of the voltage-current converter 78 is connected to the process controller 48. . Note that conductive wires 80° 82 and 84 are led out from the process controller 48 and connected to the adder/subtractor 7, respectively.
Connect it to the input side of 2.

To explain the operation of the simulator 7o configured as above, first, the feeder output command signal derived from the process controller 48 is introduced to the adder/subtractor 72 via the conductor 80, and is similarly derived from the process controller 48. The main screw output command signal to be output is also connected to the conductor 8.
2 to the adder/subtracter 72. If the process controller 48 is for the single screw extruder, there is no subtraction factor when detecting the resin pressure. Therefore, in this case, the conducting wire 84 is preferably grounded. On the other hand, when the process controller 48 controls the single screw extruder with a gear pump, 1. A gear pump drive unit output command signal is output from the process controller 48. Since this serves as a subtraction factor, it is introduced into the adder/subtractor 72 via a conductor 84. Further, when the process controller 48 controls the tandem extruder, an output command signal related to the second main screw is output from the process controller 48. Since this also functions as a subtraction factor, it is introduced into the adder/subtractor 72 via the conductive wire 84.

Therefore, in the adder/subtractor 72, if there is the subtraction element, it is subtracted from the sum of the feeder output command signal and the main screw output command signal, which are addition elements, and is output to the rectifier 74.

In this case, if the rectifier 74 is configured not to output when the sum of the addition elements is smaller than the subtraction element, it is possible to create a simulator that outputs an output signal that is more similar to the actual circuit configuration. Therefore, when the output of the rectifier 74 is introduced into the voltage amplifier 76, the output of the rectifier 74 is amplified by the amplifier 76 to a fi pressure corresponding to the output of the actual strain gauge, and is introduced into the process controller 48. On the other hand, the voltage amplifier 7
The branched output signal from 6 is introduced into a voltage-to-current converter 78 where it is converted to a corresponding current and introduced into the process controller 48 . In this case, the output of the amplifier 76 is in the range of about mV, and the output of the voltage-current converter 78 is preferably in the range of about 4 to 20 mA, which is approximately the same as the output of the actual device.

Therefore, when the output of the simulator 70 is introduced into the process controller 48, the process controller 1 roller 48 derives the feeder output command signal and the main screw output command signal based on the output signal, and the so-called closed loop resin pressure control is performed. Simulation 1 will be held. In addition,
During this time, whether abnormal values are found in the feeder output command signal and the main screw output command signal is determined to confirm whether the process controller 4 functions normally.

As described above, according to the present invention, it is possible to determine whether or not the resin pressure control system of the process controller is functioning normally without particularly energizing the resin pressure detection sensor.

That is, in an extruder, the resin pressure signal can be obtained by the simulator according to the present invention, so when testing or adjusting the process controller, the resin pressure signal of the process controller can be measured without preparing an actual extruder and actually driving it. You can easily check whether the control system is functioning properly. As a result, it is possible to reduce operating costs, reduce man-hours, and save energy consumption.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to the embodiments related to this extruder, and includes not only multi-screw extruders but also injection molding machines, compression molding machines, It can be applied to transfer molding machines, blow molding machines, etc., and it can also be used in processing machines that melt and mold metal, and various modifications can be made without departing from the spirit of the present invention. Of course.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the relationship between a conventional single-screw extruder, a process controller, and a resin pressure control system;
The figure is an explanatory diagram showing the relationship between a conventional single screw extruder with a gear pump and a resin pressure control system, and Figure 3 shows the relationship between a conventional tandem type single screw extruder and a resin pressure control system. The explanatory diagram shown in FIG. 4 is a block circuit diagram showing the interrelationship between the simulator and the process controller according to the present invention. 10... Extruder body 12... Goo 14... Cylinder part 16... Feeder part 18... Barrel 20... Screw 22... Homper 24... Rotation drive shaft 26... Feeder motor 28... Opening part 30. - Barrel 32... Lining 34... Heater 36... Main screw 38... Rotating shaft 40... Screw motor 42... Filter 44... Feeder motor driver 46... Main screw motor driver 48... Process controller 50 ...Pressure sensor 52...High-power circuit 54...Gear pump 56...Gear pump motor 58...Motor driver 60...Cylinder section 62...Rotary shaft 64...Main screw motor 66...Motor driver 70...Simulator 72・
- Adder/subtractor 74... Rectifier 76... Amplifier 78... Voltage-current converter 80.82.
84...Conductor patent applicant Toshiba Machine Co., Ltd.

Claims (1)

[Scope of Claims] fl) A process controller attached to a processing machine that melts metal, resin, etc. and forms it into a predetermined shape, and that controls the molding process of the processing machine, and is connected to a process controller derived from the process controller. It includes an electric circuit that synthesizes the pressure control system output of the processing machine based on the drive output command signal for the processing machine, and controls the pressure control function of the process controller by introducing the synthesized pressure control system output signal into the process controller. A simulator for a pressure control system, characterized in that it is configured to confirm whether or not it is possible. (2) In the apparatus according to claim 1, the simulator is a pressure control system simulator having at least an adder/subtractor and an amplifier. (3) A simulator for a pressure control system in the apparatus according to claim 2, in which a rectifier is connected to an adder/subtractor constituting the simulator. (4) A pressure control system simulator comprising the apparatus according to claim 2, in which a voltage-current converter is connected to an amplifier. (5) In the apparatus described in claim 1, the processing machine includes an extruder that molds metal, resin, etc. by rotating a screw, and the simulator receives a screw output command signal from the process controller as an output command signal. Simulator for pressure control system.