SU1328409A1 - Apparatus for controlling the process of electrochemical etching of microwire - Google Patents

Abstract

The invention can be used in ferrous and non-ferrous metallurgy in the automation of electrochemical etching processes. The purpose of the invention is to improve the accuracy of stabilization of the diameter of the microwire. The deviation of the microwire diameter t t 9 from the given one is measured at the exit of the etching bath 1 (BT) by a capacitive transducer 4, the output of which is smoothed by an inertial link consisting of the comparison element (EC) and the integrator 6, at the output of which the average signal is generated the deviation of the diameter of the microwire from the given one, which comes to the input of the block 7 is proportional-integral-differential (PID) control. Depending on the magnitude and sign of this signal, the control unit 7 forms at its output according to the PID law a signal that controls the amplifier 9, which regulates the etching current. The development of the accuracy of the stabilization of the diameter of the microwire is achieved by introducing into the device a control unit and a comparator unit. 2 Il. (L with N9 OO 4 P CO az.f

Description

The invention relates to electroplating and can be used, for example, in ferrous and non-ferrous metallurgy in automating the process of electrolytic etching. The purpose of the invention is to improve the accuracy of stabilization of the diameter of the microwire,

. Fig. „1 shows a schematic of the proposed device; in fig. 2 is a block diagram of a proportional-integral-differential control unit.

The device comprises an etching bath 1 with electrodes, a power transformer 2, a rewind mechanism 3, a transducer 4 deviating the output diameter of the microwire from a given one, a comparison unit 5, an integrator 6, a proportional-integral-disper- sional adjustment block 7, a summation block 8, the amplifier 9, a current sensor 10, a scaling element 11, and the device for scaling summing device 12 made as a scaling element 11 and a summing unit 8.

The device works as follows.

The microwire is pulled through the etching bath 1 in an electric

 the field between the electrodes, where n 5 is the change in its diameter due to the anodic dissolution of the surface metal layers. The movement of the wire is ensured by the rewinding mechanism 3. The relative deviation of the diameter of the microwire from the etching bath specified at the output of bath 1 is measured by a capacitive transducer 4, the signal from which is fed to the input of the inertial link performed on the comparison element 5 and the integrator 6 with a configurable integration time. The integrator operates in the mode of tracking the signal coming from converter 4, with simultaneous averaging. The averaged signal from integrator 6 is fed to the input of block 7 by proportional-and-integral-differential control, which, depending on the magnitude and sign of the input signal, generates a signal that controls amplifier 9, which regulates the current in the etching circuit 1. The principle of the amplifier is based on amplification and conversion.

 a direct current signal from a proportional-integral-differential control unit to an output AC voltage used to power the electrodes of the bath. The amplifier is covered by negative current feedback flowing in the circuit of the bath electrodes.

The feedback factor is adjusted by an 11-scale element, made in the form of a conventional voltage divider. Negative feedback stabilizes the etching current when the voltage drops in the AC network and the electrical conductivity fluctuations of the electrolyte in the etching bath 1. Due to the effect of negative current feedback, the output signal of amplifier 9 depends only on the level of the signal from block 7 and does not depend on the difference

voltage in the alternating current network and fluctuations in the electrical conductivity of the electrolyte in the bath 1. Any change in the voltage of the network or the electrical conductivity of the electrolyte in the bath causes a change in the current in the electrode circuit and, consequently, in the negative feedback signal, which affects the operation of the amplifier in such a way that its output signal, o, is unchanged. The disturbance introduced in the process of rewinding by an increase in the speed of movement of the wire due to an increase in its winding radius on the receiving reel is weakly expressed, since it is monotonous and therefore easily localized by the diameter stabilization circuit.

The delay in the transmission channel of the signal of the diameter deviation introduced by the inertial link is compensated to a certain extent by the differential component of block 7. Comparing element 5 compares the signal of the microwire from the predetermined diameter from the converter 4, and the same signal

but integrated by integrator 6 over a certain period of time for an average value. Depending on the sign of the signal at the output of the comparison element 5, the integrator 6 integrates this signal in the direction of its increase or decrease. When at time t: t, the integrator output is compared. In the element comparison

By the input signal from converter D, the integrator switches to the storage mode and its output signal corresponds to the average value of the monitored parameter (deviation of the micro wire diameter from the specified one), which it has at t t | .

The storage of information at the integrator output is based on its property of storing information at the moment of time when its input is disabled or input. the signal is zero. Thus, the ine () link, consisting of the comparison element 5 and the integrator 6, makes it possible to obtain at its output an averaged signal of deviations of the diameter of the microwire from the given one and to eliminate the oscillation of the signal in

The measuring channel of block 7, which makes the latter stable, does not cause a swing of its output signal, and therefore, allows improving the quality of regulation and increasing the accuracy of stabilizing the diameter of the microwire on the drive from the etching bath.

In the proposed device, an inertial element consisting of a comparison element 5 and an integrator 6 allows, with a suitable integration time in the integrator, to suppress signal ripples in the measuring channel of block 7, while the adjustment elements of the latter (proportionality factor, integration time, differentiation time) the process is tuned for optimum control quality with minimum overshoot and static error and maximum attenuation,

Consequently, an inertial link consisting of a comparison element 5 and an integrator 6 ensures stable operation of block 7 and eliminates at its input and output a signal oscillation due to unevenness of the initial diameter of the microwire, which improves the quality of regulation and accuracy of stabilization of the diameter of the microwire at the exit of the etching bath. .

The signal Y (Fig. 2) of the deviation of the controlled variable from the predetermined value is applied to the inverting input of the operational amplifiers A2 and A3. the differential component of the law

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control is formed by the operational amplifier A1, in the input circuit of which the capacitor KQ is switched on.

The operational A-amplifier A3 is the adder of the proportional (P) and differential (D) components of the law of regulation. In the common feedback circuit, 1Q positive feedback of A1 and A3 amplifiers connected in series

capacitor C is turned on to suppress output noise. The time constant of this link is set

potentiometer K.

The integrating link is made on the operational amplifier A2, in the negative feedback circuit of which a capacitor C is connected. In the automatic control mode, the integrator forms an integral AND component of the law of regulation on the input signal YC.

The outputs of the amplifiers A2 and A3 are connected to the operational amplifier A5. The transmission coefficient of the amplifier A5 is regulated, its value determines the proportionality coefficient Kp of the regulating unit. In this way,

the output signal of operational amplifier A5 is the sum of the P, I, D components, and the dynamic tuning parameters of the control unit are independent.

In the negative feedback circuit, the A2 and A5 operational amplifiers are connected in series with a capacitor Cp. The integrating link thus formed

used to effect a smooth switching of the control mode. The control unit is switched to the manual, remote control input signal.

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In the manual control mode at P1, the inverting input of the op-amp A2 of the integrator is connected to the common bus and the integrator is controlled by the non-inverting input by the signals Pg and P. Depending on which of them, the output of the control unit is changed in the direction of its increase or decrease. In the absence of control signals P5 and P, the output signal of the control unit is held at a constant level by a drift compensator (CD),

The regulator output limiter is made on the operational amplifier Ab (FIG. 2), in the feedback circuit of which two null-organs A7 and A8 are connected. When the output signal of the amplifier A6 reaches the upper (lower) set limit level Xg and (XK) the corresponding null organ, at the output of which a signal appears that compensates the input signal and supports the output signal of the amplifier A6 equal to the corresponding level of the limit. Similar limiting

The output signal affects the integrator with the 5th sensor of the deviation of the diameter of the micro-operation amplifier A4.

The economic effect of the introduction of the device is achieved by reducing waste and rejecting the irregularity of the microwire in diameter.

Claims (1)

Invention Formula Process control unit 25 for electrochemical etching of a microwire, comprising an etching bath with electrodes, a supply transformer, a current sensor, a rewinding mechanism, the generator of deviation of the output diameter from a given one, the integrator, the amplifier included in the primary winding circuit of the supply transformer, a scaling summing device made as a scaling element and a summing unit, characterized in that, in order to improve the accuracy of stabilization of the diameter of the microwire, it is equipped with a proportional-integral unit - differential regulation by the comparison unit, the first input of the comparison unit is connected to the converter from the predetermined one, the second input is connected to the output the integrator and the input of the proportional-integral-differential control unit, and the output to the integrator input, the output of the proportional and integral-differential control unit is connected to the first input of the summation unit, the second input of which is connected to the output of the current sensor, connected to the secondary circuit of the supply transformer and the electrodes of the etching bath, and the output is connected to the input of the amplifier, Yu Rt .. A8 Ying VNIILI Order 3455/30 Circulation 612 Subscription Random polygons pr-tie, Uzhgorod, st. Project, 4 Subscription