SU1341255A1 - Device for measuring cathode area in electroplating bath - Google Patents

Abstract

The invention relates to equipment for electroplating and can be used to measure the area of parts made of electrically conductive materials. The purpose of the invention is to improve the accuracy of measuring the cathode area. The device contains an electrolytic bath 1 in which the anode 2 is immersed, an additional electrode 3, the cathode 4. The anode 2 is directly connected to the output of a pulsed current generator 5, and the cathode 4 is connected through a shunt 6. The input of the generator current measurement unit 7 is connected to shunt 6. The rectifier input 8 is connected to an additional electrode 3, and the output is connected to the input of a smoothing filter 9, the output of which is connected to the second input of the summing device 10. The outputs of the comparison circuits 11.12 are connected to the separate inputs of the trigger 13. The measurement accuracy is improved by introducing into this device a generator current measurement unit, a smoothing filter, a summing device, two comparison circuits and a trigger. 3 il. with S (L

Description

The invention relates to equipment for electroplating and can be used to measure the assembly of parts made from electrically conductive materials.

The purpose of the invention is to improve the accuracy of measuring the cathode area.

Figure 1 shows the diagram of the device; figure 2 is the equivalent circuit of the galvanic bath with alternating current; on fig.Z - timing diagrams. deactivating the device.

A device for measuring the cathode area in a galvanic bath contains an electrolytic bath 1 in which the anode 2 is immersed, an additional electrode 3 and cathode 4. The anode 2 is directly connected to the output of a pulsed current generator 5, the cathode 4 is connected to the second pole of the generator 5 through a shunt 6 To the shunt 6 is connected the input of the generator current measurement unit 7, the input of the rectifier 8 is connected to the additional electrode 3, and the output of the rectifier 8 is connected to the input of the smoothing filter 9, the output of which is connected to the second input of the summing device a 10. The output of the summing device 10 is connected to one input of the comparison circuit 11, and the output of the rectifier 8 is connected to the second inputs of both the 11 and 12 comparison circuits. The outputs of the comparison circuits 11 and 12 are connected to the divided inputs of the trigger 13 at the output of which pulses are formed, the duration of which is proportional to the measured cathode area.

Figure 2 shows the equivalent circuit of the galvanic bath with alternating current, where indicated;

Cd and C are the capacity of the electrical double layer, respectively, the anode-electrolyte 45 and the cathode-electrolyte;

R and Rj are the equivalent electrolyte resistances between the anode and the auxiliary electrode and the cathode 50 and the auxiliary electrode;

A, E, K - anode, additional electrode and cathode.

Fig. 3 shows temporary diagrams that explain the operation of the device:

  the shape of the pulse current through the bath;

15 (i 5 0 jg

0

five

0

five

lljl J - voltage taken

with an additional electrode; - output voltage

rectifier;

HC) is the level of the average value of rectified voltage;

CT is the level of voltage supplied to the adder from the output of the generator current measurement unit; waveform generated by the trigger output. The device works as follows.

The impulse of different current fields generated by the generator 5 causes the voltage to appear on the electrodes of the bath, and on the additional electrode 3 with respect to the cathode 4 this voltage has a trapezoidal shape. According to the bath replacement scheme (Fig. 2), the voltage on the additional electrode when the current through the bath 1 is equal to

Ug (t) loRj +,

where t is the time after the appearance of the current pulse 1o.

The voltage form Ujlt) is shown in FIG. The voltage Ie (1) is rectified by rectifier 8 and is fed to one of the inputs of the comparison circuit II. At the same time, the rectified voltage is smoothed by filter 9 and its average value goes to one of the inputs of the summing device 10 and the second control circuit 12. At the instant of equality of the instantaneous voltage value at the output of the rectifier 8 and the average value of this voltage, the comparison circuit 12 is triggered and flips trigger 13 in one state. The trigger 13 returns to its initial state by a signal from the first comparison circuit 11, to the input of which voltage is supplied from the output of the summing device 10. In this device, a voltage proportional to the current through the bath created by the additional electrode is added to the average value of the voltage on the auxiliary electrode. The generator 5. For this purpose, the device has a shunt 6 connected to which the input of the generator current measurement unit 7 is connected. Thus, from the output of the summing device 10, the voltage is + KTo, where Ucp is the average value of the voltage on the additional electrode, K is the transmission coefficient of the generator current measurement unit, To is the current value through the bath. This voltage is greater than Ucp, so the comparison circuit II operates later than the circuit 12. If you take the timing of the comparison circuit 12 as the time reference, then the response torque of the comparison circuit 11 can be found from the ratio

1o - K1o, whence t KS.

and

Thus, the duration of the pulses received at the output of the flip-flop 13 in this device is proportional to the capacitance of the electrical double layer, and hence to the cathode area. Moreover, the duration t does not depend on the magnitude of the current through the bath, nor on the frequency of the latter.

Claims (1)

Invention Formula A device for measuring the cathode area in a galvanic bath containing A WH one five A generator of current of direct current, connected between the anode and the cathode, an additional electrode and a measuring unit connected between the cathode and an additional electrode, is required by the fact that, in order to improve the measurement accuracy, it equipped with a generator current measurement unit, a smoothing filter, a summing thinner, two comparison circuits and a trigger, and the measuring unit is designed as a rectifier, its output is connected to the inputs of the first and second comparison circuits and to the input of a smoothing filter whose output is connected To the second input of one of the comparison circuits on one of the inputs of the totalizer of the lean device, the output of the generator current measurement unit, the input of which is connected to the shunt connected into the cathode circuit of the bath, the output of the summing device is connected to the second input of the second comparison circuit, and the outputs of each of the comparison circuits are connected to the separate inputs of the trigger. FIG. 2 Cj neither u, (t} Compiled by S.Ponomarev Editor A.Dolinich Tehred I.Popovich Proofreader I. Erdeyi Order 4405/33 Circulation: 612; Subscription VYSLETS of the USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4 Fig.z