JPH07285163A - Control device of plastic extruder - Google Patents

Abstract

PURPOSE:To provide the control device of a plastic extruder capable of automatically setting the operation conditions of the extruder by simple input operation without almost requiring the knowledge about the plastic extruder. CONSTITUTION:When an operation condition selecting range estimated corresponding to a plastic raw material to be subjected to extrusion molding is set and inputted to an input means 103, operation conditions applying the optimum extrusion molding characteristics to a plastic extruder 101 are automatically calculated by the simulation calculation of an operation means 104 and the plastic extruder 101 is operated on the basis of the calculated operation conditions by a control means 104.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a plastic extruder.

[0002]

2. Description of the Related Art The operating conditions of a plastic extruder and the quality of molding process are closely related. In addition, since the influence of operating conditions on the molding quality is complicated, there are many factors due to experience and intuition. In the past, operating conditions were set based on the experience of a skilled operator, or various operating conditions were changed while operating an actual machine to select the optimum conditions by trial and error.

[0003]

Therefore, in the case of the control device conventionally applied to the plastic extruder,
The operation of setting the operating conditions of the plastic extruder is complicated, and it is extremely difficult for anyone other than a skilled person to become an operator.

The present invention has been made by paying attention to the above circumstances, and an object of the present invention is to provide a simple input operation and operating conditions of an extruder with almost no knowledge of a plastic extruder. It is an object of the present invention to provide a control device for a plastic extruder capable of automatically setting the temperature.

[0005]

To achieve the above object, as shown in FIG. 1, an extrusion molding operation in a plastic extruder 101 for kneading and melting a resin supplied in a barrel and extruding to obtain a plastic molded product. In the control device 102 of the plastic extruder for controlling, the input means 103 capable of setting and inputting the operating condition selection range defined according to the plastic molded product, and the operating condition selection range given by the input means 103 The plastic extruder 101 is changed by sequentially changing the operating condition values of the plastic extruder 101 on the basis of the machine data of the plastic extruder 101 and the raw material property data of the resin which are registered in advance. Calculated extrusion properties for the The operation means 104 for obtaining the operating condition giving the optimum extrusion molding characteristic from the characteristics, and the extrusion molding operation in the plastic extruder are controlled under the operating condition giving the optimum extrusion molding characteristic obtained by the arithmetic means 104. And a control means 105.

[0006]

With the control device for the plastic extruder according to the present invention, when the operating condition selection range expected according to the plastic molding raw material is set and input by the input means 103, the operating condition given by the input means 103 in the arithmetic means 104. Within the selected range, the values of the operating conditions of the plastic extruder 101 are sequentially changed based on the machine data of the plastic extruder 101 and the raw material property data of the resin which are registered in advance, and each simulation is performed to perform the simulation. And the operating conditions that give the optimum extrusion properties from the calculated plurality of extrusion properties.

When the operating conditions giving the optimum extrusion molding characteristics are obtained in this way, the control means 105 sets the operating conditions giving the optimum extrusion molding characteristics to the plastic extruder 101.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is a system configuration diagram showing an embodiment configuration of a control device for a plastic extruder according to the present invention.

As shown in FIG. 2, the plastic extruder 1
The resin (not shown) is kneaded and melted by the screw 4 in the barrel 3 heated by the heater 2 and extrusion molded to obtain a plastic molded product. In this case, the resin pressure gauge 5 detects the pressure of the molten resin, and the pulse generator (PG)
6 detects the rotation speed of the motor 7, and also a thermocouple (TC)
The barrel temperature and the resin temperature are detected by 8, and the detected value from this is fed back to the control device 10 via the input interface 9, and the control signal based on each detected value fed back in the control device 10 is output by the interface 1.
In addition to the heater 2 and the motor 7, the barrel temperature and the screw rotation speed are controlled via 1. Reference numeral 12 is a speed reducer.

The control device 10 operates as the input means, arithmetic means and control means in FIG. Therefore, it is possible to operate as an input means for setting and inputting the operating condition selection range expected according to the plastic molding raw material. Within the operating condition setting range given by the input means, the operating condition values in the plastic extruder 1 are sequentially changed based on the machine data of the plastic extruder 1 and the raw material physical property data of the resin which are registered in advance. Each of the simulations is performed to calculate an extrusion molding characteristic for the plastic extruder 1, and an operation as a calculation unit for obtaining an operating condition that gives an optimum extrusion molding characteristic from a plurality of calculated extrusion molding characteristics can be performed. Further, in this example, after the operating conditions that give the optimum extrusion molding characteristics were obtained, when the plastic extruder 1 underwent a trial operation under these operating conditions, the extrusion molding characteristics in this trial operation were measured and calculated. It includes an operation as a correction unit that compares the calculated value of the extrusion molding characteristic with the measured value of the extrusion molding characteristic in the trial run to correct the error in the simulation calculation. Furthermore,
When the test operation is performed as described above, it includes an operation as a second correction means for correcting the error in the simulation calculation based on the data of each state of heating and cooling for the barrel 2 during the test operation.

FIG. 3 is a flow chart showing an example of the flow of simulation calculation for obtaining extrusion molding characteristics.

As shown in FIG. 3, the extrusion molding characteristics of the extruder (resin temperature at the exit of the extruder, resin pressure, resin extrusion rate, etc.)
Is the physical property data (friction coefficient, specific heat, melt viscosity, etc.) of the material to be molded and machine data (screw type, screw diameter,
It can be calculated by simulation from the flight width, groove depth, etc.) and operating conditions (screw rotation speed, barrel temperature, etc.).

An example of the mathematical model used for the simulation is as follows.

A. Solid transport capacity Q _s

## EQU1 ## Q _s = π ² * N * H * D _b * (D _b −H) * tan (φ) * tan (θ _b ) / (tan (φ) + tan (θ _b )) * W / ( W + e) W = π / p * (D _b −H) * sin (θ) −e φ = tan ⁻¹ (V _p1 / π * N * D _b −V _p1 / tan (θ _b )) where N : screw rotational speed D _b: barrel inside diameter H: screw groove depth theta _b: helix angle of the screw p: number of threads of the flight of the screw e: screw flight width V _p1: solid plug velocity vector argument (coefficient of friction Function) B. Molten resin extrusion capacity Q _m

## EQU00002 ## Q _m = π * D _b * N * b * H / 2−b * H ³ * P _h / η / L / sin (θ _b ) / 12 where b: screw groove width P _h : Resin pressure at screw tip η: Viscosity of molten resin L: Screw length C. Power consumption E _m

## EQU3 ## E _m = η * V ² * b * L / sin (θ _b ) / H * (4 * (1 + tan ² (θ _b )) − 6 * Q _m / V / b / H) + η * V ² * e * L / sin (θ _b ) / δ / cos (θ _b ) V = π * D _b * N * cos (θ _b ) where, δ: Flight clearance of screw Book organized and explained Has been published in large numbers.
An example is as follows.

Example 1. Zehev Tadmor and Imrich Klein "E
ngineering Principles of Plasticating Extrusion "2. MJ Stevens" Extruder Principles and Operati
on "3. Kenkichi Murakami" Extrusion molding "The calculation accuracy has reached almost practical level by devising the boundary conditions of calculation by comparing the actual machine test results with the calculation results. [Table 1] shows a comparison between the calculation result and the test result based on the theory of Book Example 1 above.

[0016]

[Table 1] Here, raw material resin: polypropylene (MFR = 9) Extruder size: Toshiba Machine SE-90 (screw diameter = 9
0, L / D = 32) Screw speed: 100 rpm Next, the operation of this embodiment will be described with reference to the flowcharts of FIGS. 4 and 5.

In the present embodiment, a 32-bit CPU is used as the control device 10, and a control machine of this CPU is provided with an arithmetic machine. Therefore, an operating condition setting routine is provided in the control program. Become. Then, in the operating condition setting routine, as shown in the flowchart of FIG. 4, first, the operator interactively inputs the following data required for the simulation in the question displayed on the display screen of the control device.

A. Raw material brand code: Call the data of the raw material to be molded from the registered raw material database.

B. Operating condition selection range: Given a selectable range as operating conditions, change the combination of conditions within that range to calculate. C. Restriction condition: Specify the condition range that does not cause a problem in molding processing and judge whether the calculation result is accepted or rejected.

Upper and lower limits of resin temperature Trmax, Trmin (check resin deterioration and molding workability) Upper limit of power consumption Zmax (check overload of extruder driving motor) D. Operating condition number of steps: Specify how finely the operating condition is changed and calculated within the given operating condition selection range. In this routine, the physical property data for forming the common raw material and the screw shape / dimension machine The data is registered, and the simulation is sequentially executed in combination with the above-mentioned operating condition data given by the operator, and the following characteristics of the extruder are calculated.

Temperature of extruded resin Tr Power required to drive screw Z Degree of molten rabbit resin during extrusion X / W Extrusion amount Q Q When searching conditions for maximizing the extrusion amount in the plastic extruder 1, Of the extrusion amounts calculated from the combination of operating conditions, the operating conditions that give the maximum extrusion amount out of the cases where the limit conditions are not excluded are assigned to the specified variables, the routine is terminated, and the control is executed. Return to the main routine in the control device 10.

When checking the combination of operating conditions and the limiting conditions in the flow chart of FIG. 4, FIG.
First, K1 = 1, K2 = 1, ...
With Kn = 1, calculation starts from Kn + 1 = 1. The calculation results are T _r <T _rmax , T _r > T _rmin , X / W = 0,
Only those satisfying the condition of Z <Z _max are subject to the optimum condition search. In this example, in order to find the condition that gives the maximum value of Q, T _1set , T _2set , ... T _nset , N _sset are T ₁ , T only if the calculated Q exceeds the previous maximum Q.
Substitute the calculation conditions at that time into ₂ , ... T _n , N _s .

Next, the same calculation and retrieval are performed with Kn + 1 = 2. In this way, Kn + 1 = 1 to i, Kn
= 1 to i, ... K1 = 1 to i is repeatedly calculated.

In this way, according to this embodiment, the operating conditions that give the optimum extrusion molding characteristics can be automatically calculated by simply performing the data input operation without the experience and the setting of the operating conditions by trial and error. Can be set as desired.
Then, by operating the extruder under the determined operating conditions, a desired plastic molded product can be obtained.

[0025]

As described above, according to the present invention, the extrusion molding characteristics are repeated within the operating condition range given by the input operation by the operator by performing the simulation calculation for obtaining the extrusion molding characteristics in the operating condition setting routine. Calculation is performed, and the operating conditions for obtaining the optimum characteristics are searched for, and the plastic extruder is operated under these operating conditions. Therefore, according to the present invention, the operating conditions of the extruder can be automatically set with almost no need for knowledge about the plastic extruder, so that a good plastic molded product can be obtained without any expert. Obtainable. In addition, the operating conditions that give the maximum or optimum characteristics of the extruder can be set without trial and error of the actual operation, so that time and raw material costs can be saved.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to a claim of the present invention.

FIG. 2 is a system configuration diagram showing an example configuration of a control device for a plastic extruder according to the present invention.

FIG. 3 is a flowchart showing an example of a flow of simulation calculation for obtaining extrusion molding characteristics.

FIG. 4 is a flowchart showing an operating condition setting routine.

FIG. 5 is a flowchart showing a routine for checking a combination of operating conditions and a limiting condition.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 plastic extruder 2 heater 3 barrel 4 screw 5 resin pressure gauge 6 pulse generator (PG) 7 motor 8 thermocouple 9 input interface 10 control device 11 output interface 12 speed reducer 101 plastic extruder 102 control device 103 input means 104 computing means 105 control means

Claims (3)

[Claims] 1. A plastic extruder control device for controlling an extrusion molding operation in a plastic extruder for kneading, melting and extruding a resin supplied in a barrel to obtain a plastic molded article. Input means capable of setting and inputting the operating condition selection range defined by the above, and mechanical data of the plastic extruder and raw material physical properties of the resin registered in advance within the operating condition selection range given by the input means. Based on the data, the simulation of sequentially changing the operating condition value in the plastic extruder is performed to calculate the extrusion molding characteristics for the plastic extruder, and the optimum extrusion molding is performed from the calculated plurality of extrusion molding characteristics. Calculating means for obtaining the operating conditions given the characteristics, and the maximum value obtained by the calculating means. An apparatus for a plastic extruder, comprising: a control unit that controls an extrusion molding operation in the plastic extruder under an operating condition that gives suitable extrusion molding characteristics. 2. The computing means obtains operating conditions that give the optimum extrusion molding characteristics, and then performs a trial operation of controlling the extrusion molding operation of the plastic extruder by the control means under the operating conditions. A correction unit is included that measures the extrusion molding characteristics in the test run, and compares the calculated calculated extrusion molding characteristics with the measured extrusion molding characteristics in the test run to correct the error in the simulation calculation. The control device for a plastic extruder according to claim 1, wherein: 3. The calculation means obtains operating conditions that give the optimum extrusion molding characteristics, and then performs a trial operation of controlling the extrusion molding operation of the plastic extruder by the control means under the test operating conditions. The control device for a plastic extruder according to claim 1 or 2, further comprising a second correction unit that corrects an error in the simulation calculation based on data of each state of heating and cooling of the barrel during a test operation.