JPS606426A - Non-interacting controlling apparatus of injection molder heating cylinder - Google Patents

Abstract

PURPOSE:To perform the electric power control of a heating source and the control of the temperature, by collecting informations of resin temperatures at two or more temperature detecting points, for example, heat interexchange in a heating cylinder layer, heating-up due to shearing by a rotating kneading screw, etc. and making them non-interactive. CONSTITUTION:Temperature detecting means Sc1-Sc3 (cylinder temperature detecting elements) and Sr1-Sr3 (resin temperature detecting elements) that are in number of (m) (m>=2) are provided in a heating cylinder 1 longitudinally thereby detecting the temperatures theta'c1, theta'c3, theta'r1-theta'r3 of the cylinder and the resin. The detected quantities are converted to digital quantities by an analog- digital converter 5 and are inputted into an arithmetic circuit 6. The operation in the arithmetic circuit 6 is excecuted in a non-interacting control algorithm. The operated results are outputted from a digital-analog converter 9 as analog quantities and are led into power control apparatuses 101-103 to feed electric power to hand heaters 21-23 thereby controlling the temperature of the resin in the cylinder 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature control device for a heating cylinder for heating, melting and kneading resin in an injection molding machine.

Injection molding machines supply resin into a heating cylinder, heat it, melt it, and knead it before injecting it.At this time, the properties of the resin change depending on the amount of heating.
It is necessary to keep the temperature of the resin constant.

Traditionally, injection molding machine heating cylinder temperature control is.

The temperature of the heating cylinder was measured and the power supplied to a heating source such as a band heater was turned on and off to control the heating cylinder to maintain a constant temperature. However, this temperature control measures the temperature of the outer surface of the heating cylinder, does not take into account the heat lag in the radial direction of the heating cylinder, and does not accurately measure the temperature of the resin melted and kneaded in the heating cylinder. Temperature control was not possible. In addition, 1 For example, 2 Patent application No. 57-6 filed by the inventor on April 26, 1982
Although it is possible to accurately detect the temperature of the resin by using the method described in No. 8704 entitled "Temperature/mother turn detection method for injection molding machines, etc.", it is possible to accurately detect the temperature of the resin. Since this is not taken into consideration, it merely controls the power supplied to the band heater.

This was not sufficient to provide accurate temperature control of the resin.

SUMMARY OF THE INVENTION An object of the present invention is to provide a heating cylinder temperature control device for an injection molding machine that can solve the above-mentioned conventional drawbacks and accurately control the temperature of resin.

According to the present invention, in a device for controlling the temperature of a heating cylinder of an injection molding machine, m(
m〉2) means for detecting the temperature of the resin in the heating cylinder, and receiving m outputs of the temperature detecting means;
means for performing calculations using a non-interfering control algorithm;
An injection molding machine heating cylinder non-interference control device is obtained, which is controlled by m outputs of the calculation means and has means for supplying electric power to a heating source of the injection molding machine.

In the present invention, effects such as heat exchange within the heating cylinder layer, heat flow due to the movement of the molten resin that is injected and shattered while being heated, and shear heat generated within the resin as the kneading screw rotates are considered. The power of the heating source is controlled by treating it as a mutual interference system and making the mutual interference system non-interfering.

The characteristics of the injection molding machine system will be explained below with reference to FIG. In the figure, 1 is a cylinder.

2 indicates a heater, 3 indicates a resin, and 4 indicates a glue.

Injection molding [-Cylinder temperature θ in zone i when divided into zones in the axial direction as shown in FIG. 1 [
℃] and the resin temperature θ, □[℃].

It is expressed by the following differential equation.

Margin below ・-ha to Q′′　2　-- given name Pa Q "Kake" Here, each symbol is 〇: Nucle groove cross-sectional area [m2].

A Nijilinda cross-sectional area C, m2:] + BO Nijilinkinner surface area [m2], B1 Nijilinda outer surface area [m2]
], ΔX: axial length of one zone [m], a density of Nijilinda [kJ/m3], Cc specific heat of Nijilinda (: J
k・℃].

Thermal conductivity of λ Nijilinda [W/m・℃], αi: Heat radiation coefficient [W/m2・℃], β,: Transfer coefficient between the cylinder and the cylinder (W/m2・℃L q4, 4: Amount of heat supplied (J/m2) (heating force per area of 9), θa: Ambient temperature [°C].

The specific heat of [J/! ,・℃), V: Resin flow rate (m/5)
(v-2πr60) 1 n: Nucle rotation speed [r
pm]+r: screw radius [m], Qdi: shear calorific value per volume [W/m''].

Therefore, in the case of three zones, the differential equations of equations (1) and (2) -@i=1,2,3 can be reduced to the state equation corresponding to the system diagram shown in Figure 2.

Remainder 6 Cross=AX+Bu+W y=Cx ×=(θ・.10'c2θ'o5θ'yl ``β2ginii'(4)''= (qhI J, 2qh3)'y-(θ'r10',,2θ' r6)′w=(000q
41 Qd2 Qd3)', each element of matrix A is.

The following is Kinpaku all"" CKai+, λ4+, β1)' a12=
to λ1' a14= to β1'a21- to λ2・a22
=-(Kα2+2 to λ2+ to β2)・a23= to λ2
・β252 to β2(6) ``52''Kλ5' a+3-CKa5+ to λ5+ 83
)” a56= to β3a412 to β1'a21u to βr
1 a52"Kβr2"54=Kv2' a55= (K
f? r2+Kv2) β65=KBr5' ``65-Kv
5''66- (Kl?r3+Kv3).Here, ()' indicates the transposed matrix.

θ′c1″″θc1−θa・θ′c2=θc2−θa
・θ'c3=θC"θa(7) θ'r1=θr1-08・θ'r2=θr2-08.θ
'r5-θr3-08.

For such a system, the condition under which non-interference is possible is expressed as, where each element of D is 1? with reference to equation (6). r
It is composed of i. K7? ri is cylinder 1 and resin 3
Since it is a coefficient related to heat transfer and satisfies the condition of equation (8), non-interference is always possible.

As shown in Figure 3 for the above system.

u=Kx10Lv ””(’1 ’2 ’3)・　°゛ Deinterference is achieved by applying three-state feedback.

Here, each element in the feedback matrix is an element of A.

k12″-β121 to 21 knees (a54a41/a52
) - β211 to 23 knees 24 = a54 (a22+ to 22 - β44) / 'a521 to 32 - (85286)'
63) ``32 (1])ksa--a511a65/
a63. k3s-β65(85+ks5a55)/a
It is expressed as u. Note + kll + k22
In r k55 + k14 + k25 +, S is set to obtain predetermined characteristics.

It is recommended to perform non-interference as described above.

One input V・(1≦1
≦3) is one output θ'ri(
'≦i≦3).

Further, one output θ'r1 is influenced by only one input V. As a result, in injection molding machines.

A control system can be configured for each zone according to the state of the resin, making it possible to increase the granularity of temperature control.

In the present invention, the new vector V is as shown in FIG.

Let r ”” (r 1r 2 r 3 )'. Here, r indicates the target value of the system, that is, the set temperature.

FIG. 5 is a block diagram showing an embodiment of the present invention to which the above-described non-interference is applied. In fig.

1 is the heating cylinder of the injection molding machine, and is made of thick iron and has a cylindrical shape. Three band heaks 21 to 23, which serve as heating sources, are wound around the outside of the heating cylinder 1. Sr1 to Sr5 are the temperature of the resin 3 θ7. Temperature detection terminals +Sc+ to Sc5 for detecting temperatures .theta.'1.3 are temperature detection terminals for detecting temperatures .theta.'c1 to .theta.'c5 of the cylinder 1. Among these, the temperature detection terminals Sr1 to Sr3 are based on the description in the above-mentioned Japanese Patent Application No. 1987-68704, which has already been filed by the present inventor. It consists of a thermocouple inserted deeply toward the heating cylinder 1, and the temperature θ′r] (1<
output an electromotive force commensurate with i<3).

This xA=(θ-1"c2 θ'c6θ-4"f2
The electromotive force of "j3) is converted into a digital quantity xD by the analog/zotal converter 5 and inputted to the arithmetic circuit 6. The arithmetic circuit 6 executes the arithmetic operation based on the above-mentioned non-interference control algorithm. That is, XD is input to matrix calculation units 61 and 62. Matrix calculation unit 32 inputs C
Execute the calculation of xD and find the detected temperature yD=(θ71θ′r2
0'r3)' is output. This detected temperature yD is displayed on the display 7 and is input to the subtracter 63. On the other hand, the desotal amount corresponding to the set temperature rD inputted from the input device 8 is inputted to the subtracter 63.

The subtracter 63 executes 'DVD' and calculates vD-(v1v2v
6) Output '. VD is input to the matrix calculator 64. KXD and LvD output from the +Jx calculation units 61 and 64, respectively, are added together by an adder 65 and output from the calculation circuit 6 as uD. The desotal quantity uD outputted from the arithmetic circuit 6 is input to the digital-to-analog converter 9, which outputs the analog quantity uA. This signal is input as a control signal to the power control devices 101 to 103, and the power control devices 101 to 103 supply power according to this control signal to the band heaters 21 to 23, respectively. Here, power control devices 101 to 103. The control object consisting of the band heaters 21 to 23 degrees and the heating cylinder 1 corresponds to the part surrounded by the dotted line in Fig. 3, and uA is input and the temperature detection terminals Sri to Sr3 and Sci to S are Outputs XA.

Note that when a microcomputer is used as the arithmetic circuit 6, the value of K of the matrix arithmetic unit 61 may be calculated by this microcomputer, and the determined constant value may be stored therein.

The value of K is calculated in advance by another calculator.

Only the constant value may be stored in the memory of the microconbeater. In any case, during operation, online control is performed by a microcomputer using these constant values. ! ,Ta. Even if the heating cylinder 1 of the injection molding machine is replaced, there is sufficient room in the storage device of the microconbeater, so the above constant values for the scheduled heating cylinders should be stored in the storage device in advance. You can also do it.

According to one aspect of the present invention, as is clear from the above description.

Collect information on resin temperature at at least two or more temperature detection points,
The clever application of decoupling has the effect of precisely controlling the temperature of the resin.

[Brief explanation of drawings]

Figure 1 is a diagram for explaining the characteristics of the system of an injection molding machine to which the present invention is applied, Figure 2 is a system diagram of an injection molding machine using the state space method, and Figure 3 is an injection molding machine using the state space method. Figure 4 is a diagram of a non-interference control system to which the present invention is applied for an injection molding machine using the state space method, and Figure 5 is an implementation of the present invention to which the non-interference of Figure 4 is applied. FIG. 2 is a block diagram illustrating an example. DESCRIPTION OF SYMBOLS 1... Heating cylinder, 2.21-23... Band heater, 3... Resin, 4... Screw, 5... Analog-digital converter, 6... Arithmetic circuit, 61, 62
．． 64...Ma) IJ calculation unit, 63...Subtractor, 6
5...Adder. 7... Display device, 8... Input device, 9... Digital analog converter, 101-103... Power control device. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. In a device for controlling the temperature of a heating cylinder of an injection molding machine, a means provided on the m (m>2) side in the axial direction of the heating cylinder and detecting the temperature of the resin in the heating cylinder; An injection molding machine comprising means for receiving m outputs of the means and performing calculations according to a non-interfering control algorithm, and means controlled by the m outputs of the calculation means for supplying power to a heating source of the injection molding machine. Molding machine heating cylinder non-interference control device.