SU1260419A1 - System for automatic monitoring of mean thickness of electrodeposited coating - Google Patents

Abstract

The invention relates to electrochemistry equipment and can be used to automate the plating process. The purpose of the invention is to improve the control accuracy by automating the process, which is achieved by introducing new units and functional connections, which allow automating the process of controlling the thickness of the electroplated coating. Sys- The automatic control of the average thickness of the electroplated coating contains an electroplating bath 1 with a cathode K and an anode A, a coating measurement sensor 2 placed in the bath, a thickness measuring device 3, shunt 4, a rectifying unit 5, a switch 6 signals, a computer 7, a timer 8, 9 current density regulator. The thickness measurement device 3 is connected to the sensor 2, one switch input of the signal 6 is connected to shunt 4, and the other is connected to the output of the device 3 for measuring the voltage. The input of the current density regulator 9 is connected to the output of the computer 7, and the output is connected to the vertical aggregate 5. The control accuracy is achieved by introducing a thickness measurement device, a signal switch, and a current density regulator into this system. I zp f-ly, 4 ill. i (L C go O5 O 4ib CO

Description

"

The invention relates to an equipment for electrochemistry and can be used to automate the processes of electroplating.

The purpose of the invention is to introduce precision control by automating the process,

FIG. 1 is a block diagram of an automatic coating thickness monitoring system; in fig. 2 is a block diagram of a measuring device that is thick during coating; in fig. 3 shows the dependence of the resistance of the metal to be coated on its thickness; FIG. 4 shows a block diagram of the algorithm for calculating the average thickness and current density in the coating process.

The system of automatic monitoring of coating thickness and regulation: current density in the bath contains (fig. Electroplating bath with cathode K and anode A, coating measurement sensor 2 placed in the bath, thickness measuring device 3 connected to the sensor, shunt 4 connected to the anode A, rectifier unit 5, connected to anode A and cathode K of the bath, switch 6 signals, one input of which is connected to the output of a thickness measuring device, and the other - shunt 4, computer 7) to which a switch is connected via an interface (not shown) 6 signals and t Aymer 8, the outputs of which are connected to the inputs of the thickness measurement device 3, the switch 6 and the computer 7, the current density controller 9, the input of which is connected to the computer and the output to the rectifier unit 3.

The system works as follows

The pulse signal from the thickness sensor 2 enters the device for measuring the thickness 3, turns into a binary code, and through the switch 6 enters the computer. To measure the active cathode cathode, the signal from the mount through an analog-to-digital converter (ADC) is not shown, the switch 6 is fed to the computer 7 at an appropriate time. Timer 8 controls the system according to the corresponding time diagram. To the input of the current density control unit 9, a correspondingly calculated binary code from the computer is fed through the interface, and its output gives a constant: 60419

the voltage required to regulate the current of the rectifier unit.

Thickness measurement device 3

5, the trg coil contains (FIG. 2) an electroplating bath 10, a resistor coating thickness sensor, which consists of two platinum resistors 1 1 and 12, the resistor 11 being connected to

 the cathode K and the metal on it are spun, the amplifiers 13 and 14, whose inputs are connected to platinum resistors I and 12, the differential amplifier 15, whose inputs are connected

. 5 to the outputs of amplifiers 13 and 14, the ADC 16, whose analog input is connected to the output of the differential amplifier, and the output to the switch 6 of the system (Fig.), A digital analog converter (DAC) 17, whose input

connected to the output of the ADC 6, the coating thickness indicator 18, which is connected to the digital laboratory display module 17 and which is connected to smooth the thickness readings

25, a capacitor 19, a pulse generator 20, one output of which is connected to the input of the DAC 17, the generator being synchronized from 8 (Fig. 1), an adjustable power amplifier 21,

 one input of which is connected to the second output of the generator, and the other adjustable input through the feedback circuit (not shown) to the output of the PAP 17, output of the power amplifier p35 via capacitors 22 and 23 to the resistors 24 and 25 of the load, and the latter are connected to platinum resistors 11 and 12p which are grounded through capacitors 26 and 27.

0 The thickness sensor works according to the principle of measuring the resistance when the metal grows on a thin (10 µm thickness 1 mm wide) platinum film coated on a dielectric, or

 fine platinum wire. With increasing tolcine of the growing metal, the resistance decreases. Measurement of the resistance, film in the bath during the coating process, but only in a pulsed manner, since it is necessary to separate galvanically the measuring and feeding circuits of the bath. The measurement of the resistance of the film is made by short (in-20 µs) pulse 55, which does not affect the change in the thickness of the coating. The dependence of the resistance on the increasing thickness is different for metals and

it is pre-entered into the permanent memory of the computer (for example, the dependence of the resistance change for zinc on the thickness is given in Fig. 3).

The resistance of the growing metal is measured periodically at intervals, set by the timer of the Interpolir systems, the data on the curves previously entered into the computer, the thickness of the coating is determined by the magnitude of the resistance.

Structurally, the sensor is made of a plastic box with holes in which are placed two rods of plastic coated with platinum windings. The resistor, which builds up the metal for a more uniform coating, is connected to the bath cathode at several points. Winding can also be made of platinum thin (UP micron) wire.

To determine the optimum average thickness of the coating on the cathode, the sensor location in the bath should be found empirically. After termination of the coating process at the cathode, the sensor is connected to the anode of the bath and thus the metal is removed from it, which is of great importance when coated with precious metals. Therefore, it is advisable to put two sensors in the bath, which are immersed through each coating cycle.

To increase the measurement range of the sensor and the accuracy of measurement with increasing thickness of the metal to be coated, the amplitude of the measurement pulse applied to the sensor increases. This is done using a controlled pulse power amplifier 21, which changes amplitude with feedback from a DAC 17 or from a computer output.

The system of automatic control of the coating works according to the following algorithm.

The following data is entered in advance in the permanent memory of the computer: specific. metal weight d (g / cm); Electrochemical equivalent of metal C (g / Ach) of the table of curves of the dependence of the resistance R (Ohm) on the coated thickness 1 (µm) of the sensor for each metal.

Resistance R is calculated from the amplitude of the pulse cp

ten

604194

given from the measurement device in A1SCH. At the beginning of the galvanic process, the following data is entered into the computer operating memory using a typewriter or display:

- required thickness of coating 1 (µm),

- approximate, the duration of the process T (h)

- growth rate table

thickness 1 at time T through periods n,

table of the dependence of the cathode area SK on the bath current ty through shunt S | -F (1y);

- current strength limits P., ... and

/, 7 MIN

ABOUT. ).

Algorithms work program cars

A galvanized coating system is shown in FIG. 4. In the first block, the covered cap 1 on the cathode is calculated by sensor data at certain time intervals n (for example, after 1 min), set by the timer.

In the second block, according to the second law, Farad calculates the time yield.

P

current "(%) at the moment

t, t / n:

The third unit checks the current density through the bath. The area of the Si-part is determined by the previously entered table of the dependence of the area on the current through the shunt connected in the bath. The initial current is determined by the recalibration unit calibration performed in advance.

For known areas, current density values are determined. The current density of the fitting units, such as VAKR and TE1, is automatically maintained with an accuracy of 1P%, and such accuracy for coating with precious metals is insufficient.

If the current density P through the vacuum is less than PC ;, „, then the computer issues a signal through the interface and the current density control unit increases the current through the bath to the rectifier unit, and with a larger D max it decreases.

The quarter block prints the current data at the moment of time the coating thickness is 1 (µm), the output is then-S1

y PE () f current pannas t ,, (, A) pggschts details S ,, (dm).

Fifth unit checks the metal build-up rate using tabulated data. If there is a mismatch, the rate of increase of the metal of the CMU changes the current of the bath 1.

The sixth block checks the magnitude of the increasing metal thickness by. the cathode. If the appropriate value of 1 is reached; l; The computer shuts off the current and the printout. The end of the work required, the data is 1p, s ,. J 1 and others. But if the thickness is not sufficient, a reduction occurs to the heading and the calculation process is repeated to those values. when the required thickness of the coating is reached.

Thus, the 1–1m image of the 5th pritcheney of the Dongle sensor, the THREATS of the coating in the auto-current ipi-i кл ч кл ™ system of the ZVM system, allows to increase the accuracy of the control of the galvanizing process. monitor the metal thickness to be increased and adjust the current density in the bath J, the system allows to control the setting -: - determine the main parameter - the average thickness: well, coating with an accuracy of 3-4% 5 and maintain the required density of the bath up to 5%,

. The sensor in the system mokhet byg-: used for all metals (except P71atiny), The use of this .chk-9v

CZ 3 automated system even allows to improve the accuracy of consumption of MCTgj-i.na scrap, improve the quality of the coating to the producers-usht ore.,

 ABOUT

with n and

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the input that is connected to, and to, zu, ;; goyust1 iyme reni toltypa, ret y, nto.kh: 1M dense current, current input, connected to the output of a computer., p, s: the main unit, Gigrich bbi; made short ;; БУУ; i

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new: ;; ri; a. sdtchikg. dug in, | class ;; : tsat i, i g: and golpi and dow / sa etching metal t

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- to A1, dl dl; sensor.

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Editor M. Dylyn

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FIG A

Compiled by S. Ponomarev

Tehred M. Khodanich. CorrectorsA.T. sko,

Order 5193/23 Circulation 615 Subscription

VNISHI USSR State Committee

inventions and discoveries 113P35, Moscow, F-35, Rautska nab., d. A / 5

Production and printing company, Uzhgorod, st. Project, 4

Claims (1)

Claim 1. The system of automatic monitoring of the average thickness of the galvanic coating, containing a working bath, a rectifier, a shunt connected to the anode, a cathode, a coating thickness sensor, which is stationary mounted in the bath, controls a computer, and does not I mean that, in order to improve the accuracy of control by automating the process, it is equipped with a measurement tool 20 toP1i -; s connected to the sensor tolzeiny, komyautgtorom signals, one input of which is connected to the shunt, and the other - to the output of the thickness measuring device controller dense • ^e ti current input connected to the output of a computer, i output to the rectifier, moreover, the thickness sensor is made of two spo-ISDG; χ resistors. ? ΰ 2. System according to l. 1 . On the other hand, the point is, 'Fri, d. ng-ye set the angle of the sensor. one of which is connected to Qatar to die · whether; ⁷ thicknesses, and the other to the anode for picking metals about the sensor; 126P419 FIG. 4