SU889754A1 - Device for automatic control of current density in electroplating bath - Google Patents

Description

(iJif) DEVICE FOR AUTOMATIC REGULATION OF CURRENT DENSITY, 8 GALVANIC BATH

one

The invention relates to electroplating and can be used to automatically regulate cathode current density during deposition of electroplating.

The closest to the invention in technical essence and the achieved result is a device for automatic control of current density in a galvanic bath containing electrochemical degreasing baths and a working, connected in series measuring electrode permanently installed in an electrochemical degreasing bath, power supply units equipped with shunts, additional resistance and controlling the computational complex Tl.

However, with significant changes in the total area of the parts loaded into the bath, this device has low accuracy of current density control due to current redistribution between the measuring electrode and the suspension with the details in the electrochemical degreasing bath.

The purpose of the invention is to increase the accuracy of current density control .:

This goal is achieved by the fact that the device for automatic measurement and density control

10 current containing electrochemical degreasing baths and a working, calibrated area plate installed in an electrochemical degreasing bath, adjustable

IS bath power supply units equipped with shunts, a control computer complex, the first input of which is connected to the measuring output of the power supply unit of the working bath, and the first output - to the regulating input of this block, a voltage setpoint detector, a detector zero, a circuit comparing, three keys, a trigger, a loading gauge galvanoautomat, an electrochemical degreasing bath load cell connected in series, an inverter and an And circuit, the second input of which is connected to the galavanoavtomat loading gauge and the output to the first trigger input, The input of which is connected to the output of the zero detector and the output to the control inputs of all keys, the measuring output of the power supply unit of the electrochemical degreasing bath is connected to the input of the first key, the first output of which is connected to the second input of the control computer complex, and the second output to the first input comparison circuits, the second input of which is connected to the second output of the control you. the numerical complex, and the output with the detector zero input and through the second key to the input of the voltage supply, the output of which is connected to the regulating input of the power supply unit of the electrochemical degreasing bath, the negative bus of which is connected to the input of the third key, the first output of which is connected to a calibrated area plate, and the second output is with the cathode circuit of the electrochemical degreasing bath.

The drawing shows a structural diagram of devices for automatically controlling current density in a galvanic bath.

The device contains electrochemical degreasing baths 1 and a working 2 with anodes installed in them 3. suspension C with parts, plate 5 of the calibrated area, power supply unit 6 for the electrochemical degreasing bath, power supply unit 7 for the working bath, voltage setting unit 8, keys 9, 10 and 11, detector 12 zero, comparison circuit 13, trigger 14, circuit 15 And, inverter 16, galvanoautomator loading sensor 17, electrochemical degreasing bath loading sensor 18, control computer complex converters 19-22, power amplifier 23, control yusch th computing machine (CFM) 24.

The electrochemical degreasing bath loading sensor 18 is connected via an inverter 16 to the first input of circuit 15 I, the second input of which is connected to the galvanic automatic loading sensor 17, and the output to the first trigger input 14. The second trigger input 14 is connected to the output of the detector 12

the zero and the output are from the control inputs of the keys 9 10 and 11. The measuring output of the power supply unit 6 of the electrochemical degreasing bath is connected to the input of the key 10. The first output of the key 10 is connected through the converter 20 of the control unit 21 to the first input of the control device 24 and the input of the comparison circuit 13, the second input of which is connected to the converter 19 of the control unit, and the output through the switch 9 with the input of the voltage setting device 8. The output of the voltage setting device 8 is connected to the control input of the power supply unit 6 of the electrochemical degreasing bath, the negative bus of which through the key 11 can be connected to a calibrated plate 5 or to the suspension 4 with details. The measuring output of the power supply unit 7 of the working bath through the converter 22 of the control unit is connected to the second input of the control unit 24, the first output of which is connected to the converter unit 19. The control unit 21 and the second output through the converter 21 control unit power amplifier 23. The output of the power amplifier 23 is connected to the control input of the power supply unit 7 of the working bath.

The device works as follows.

Suspension 4 with parts from the loading position of the galvanoautomat enters the electrochemical degreasing bath 1, where the total covered area of the parts is determined, and then into the working bath 2.

The power supply unit 6 of the electrochemical degreasing bath operates in the mode of stabilization of the current density and is tuned to the current-voltage characteristic of the bath,

The device has two modes of operation: Adjustment and Regulation

Due to the change in the technological parameters of the electrochemical degreasing bath 1 (temperature of the concentration of components, etc.), its volt-ampere characteristic may change. The power supply of the electrochemical degreasing bath at the same time is not tuned to the nominal current density, which leads to an adjustment error. To overcome this drawback, the Adjustment mode has been introduced.

In this mode, the device functions immediately before loading the bath of electrochemical degreasing, when the suspension 4 with the parts is in the loading position of the galvaioautomat and the bath 1 of the electrochemical degreasing is not loaded. In this case, the loading sensor 1 of the gelvioavtomat works, and a high potential appears at its output, a low potential at the output of the electrochemical degreasing bath loading sensor 18, a low potential at the output of circuit 15 And, trigger 1.

The high potential at the output of the trigger 1 switches the keys 9, Yu and 11 to the position corresponding to the Adjustment mode. In this mode, the key 9 is closed, the measuring output of the electrochemical degreasing bath power supply unit 6 is connected with the key 10 to the first input of the comparison circuit 13, and its minus bus with the key 11 to the calibrated plate 5. The current input is supplied to the second input of the comparison circuit 13.

When the voltage-current characteristics of power supply unit 6 and bath 1 are mismatched, the current of plate 5 is different from the rated current by Zn which should be ensured by a properly configured power supply unit 6 of the electro-hygienic degreasing bath. The current information of the plate 5 of the calibrated area is supplied from the measurement output of the power supply unit 6 through the switch 10 to the comparison circuit 13, the output signal of which is proportional to the difference of this value. The value of 3 cr is calculated by the PSU 2 by the formula

.9X0

ECHO

..NOM-k.NOM. P

where is the nominal current density in the bath of electrochemical degreasing; S is the plate area of 5 calibrated area.

The imbalance signal from the output of the comparison circuit 13 through the closed key 9 is supplied to the voltage selector 8, which is connected via a regulating input to the winding of the voltage setpoint of the magnetic amplifier of the electrochemical degreasing bath supply unit 6. The current through this winding changes until the current of the measuring plate 5 becomes equal to the nominal one. In this case, the signal at the output of the comparison circuit 13 is equal to zero, and the current-voltage characteristic of the power supply unit 6 is combined with the current-voltage characteristic of the electrochemical degreasing bath 1.

The presence of a zero at the output of the comparison circuit 13 leads to the fact that

A high potential is formed at the output of detector 12 zero. The trigger 1 is switched, a low potential appears at its output, and all the keys are switched to the position corresponding to the Regulation mode.

In this case, the key 9 is open, the measuring output of the power supply unit 6 of the electrochemical degreasing bath with the key 10 is connected to the second input

UVK, and its minus bus key 11k cathode circuit of the electrochemical degreasing bath.

In the regulation mode, the device operates as follows.

Upon receipt of the suspension C with details from the position of loading the galvanoautomat in the electrochemical bath. degreasing its power unit 6, operating in stabilization mode

current density, exposes the current through E U L

bath 71, proportional to the area S boot. Information about the magnitude of this current comes from the measuring output of the power supply unit 6 through the key 10 and the converter 20 to the ACU 2.

UVM 2 calculates the total undercover area of parts by the formula

, 9x0

55X0

H.HQNV where K is a coefficient depending on.

forms the workpieces, and remembers it. Upon receipt of the same suspension C in the working bath 2, the ACM 2t calculates the amount of current Z0 needed to obtain a quality coating and, according to the formula

R.V.

Sd

Jo- 5-1.Н01А

where is the cathode current density

in the working bath 2. The setting value of the current DO of the working bath 2 is supplied from the output of the high voltage amplifier 2 through the converter 21 to the input of the power amplifier 23 whose load is the control winding of the magnetic amplifier (not shown) of the unit 7. Simultaneously with the measuring output of the unit 7 The power supply of the working bath through the converter 22 to the second input of the ACU 2k receives information {zmatsi about the actual value of the current of the working bath 2. The current through the working bath 2 is corrected by the ACU 2 to

as long as it becomes equal to the rated current.

For any suspension with details, the current density in the working bath 2 is kept constant and equal to the nominal value, which ensures a coating of the required quality.

Claims (1)

1. USSR author's certificate If 600217, cl. C 25 D 21/12, 1976 ..