JPS60128296A - Device for automatic control of plating current - Google Patents

Abstract

PURPOSE:To improve electrode efficiency and to maintain a constant coating weight of plating by generating electrode efficiency by a function from a line speed and plating current density so that overall current reference can be compensated. CONSTITUTION:A titled device is provided with calculation circuits 10, 12, a function generating circuit 13 which determines electrode efficiency by the prescribed function with the current density from said circuit and the line speed of a strip 1 as variables and a compensation circuit 14. The circuits 10, 12 calculate the current density of plating cells 3a-d from the total sum of the plating current. The circuit 14 compensates the 1st current reference by the above- described electrode efficiency and generates the 2nd current reference. The circuit controls the current according to the total sum of the plating current and the 1st current reference compensated so as to obtain the plating current density in a prescribed range in accordance with the line speed of the strip 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an apparatus for controlling plating current density within a certain range, and particularly for compensating for excess or deficiency in the amount of plating that occurs when changing the number of metx cells.

[Prior art]

Conventionally, this type of control device mainly controlled the total current of the Metx cell without strictly controlling the plating current density. The plating current density is calculated from the current value of each mesh cell, its electrode length and plate width, and the total current is calculated from the target amount, plate width, electrode efficiency and line speed. As long as these plating conditions do not change, the total current is controlled to be constant, and the amount of plating deposited is controlled to be constant. However, in the latest plating processes, it has become necessary to control the plating current to a constant value and to control the plating current density within a certain range. According to K, this is due to the need for improved gloss on the plated surface, improved electrode efficiency, and improved corrosion resistance.

FIG. 1 is a block diagram of a conventional automatic plating current control device. Reference numeral 1 denotes a strip to be plated which advances in the direction of the arrow shown in the figure, 2 a detector for detecting the line speed of the strip 1, 3a to 3dV'i a metsuki cell for plating the strip 1, and 43 to 4d supplied to the metsuki cells 32 to 3d. 5a to 5d are rectifiers that supply the plating current; 6a to 6dii are controllers that control the current supplied to the mesh cells 33 to 3 dK to a predetermined value through the rectifiers 5a to 5d; 7a to 7 dU plating current detectors; A distributor that distributes the current and supplies it to the controllers 63 to 6d; 8 is an adder that adds up the plating current according to the outputs of the detectors 4a to 4d; 9 is a PI (proportional, integral) controller;
The output signal is supplied to distributors 7a-7d. 10 is a calculation circuit which calculates the difference between the line speed of the strip l obtained via the detector 2 and the current reference and supplies it to the adder 10a.

The adder 10a calculates the difference between the total plating current of the adder 8 and the output of the calculation circuit 10, and supplies the difference to the PI controller 9. This is a current reference circuit that calculates a total current reference from the 11Vi basis weight, plate width, electrode efficiency, and line speed, and supplies this to the calculation circuit 10.

Next, the operation will be explained. The plating currents supplied to each of the mesh cells 3a to 3d are detected by detectors 43 to 4dK, and added by an adder 8. The sum of the plating currents thus determined is calculated by an adder 10a as a difference from the total current reference of the calculation circuit 10, and is supplied to the controller 9.

The PI controller O supplies the current reference distributed based on the difference provided by the adder 10a to the distributors 73-7d. The distributors 7a to 7d distribute the plating current to each controller 6.
a to 5d, rectifiers 53 to 5d, and rectifiers 4a to 4d to Metxcells 3a to 3d.

The line speed of the strip 1 detected by the detector 2 is input to the calculation circuit 10, and the calculation circuit 10 increases or decreases the total current reference set by the current reference circuit 11 in accordance with the increase or decrease in the line speed. For example, when the line speed increases, the total current reference is increased.

In this way, the conventional control device determines the total current of the plating current in accordance with the moving speed of the strip, and changes the current density of each mesh cell according to this, so that the plating current density is adjusted to a predetermined eight reconnaissance value. had the disadvantage that it could not be controlled by ffi.

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and focused on the fact that the plating electrode efficiency varies depending on the line speed and plating current density. It is an object of the present invention to provide an automatic plating current control device that compensates the overall current standard of a metal cell by considering the plating electrode efficiency with respect to the density, and controls the plating current so that the amount of plating on a strip is constant.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. In Fig. 2, parts with the same symbols as in Fig. 1 indicate the same parts, and the output power of the 12Vi adder 8 and the plating current density are expressed as follows. A calculation circuit 13 calculates the plating electrode efficiency by referring to a predetermined plating electrode efficiency function using the plating current density calculated by the calculation circuit 12 as a variable; 14 a plating electrode efficiency of the function generation circuit 13; This is a compensation circuit that performs final compensation on the total current reference supplied from the calculation circuit 10 and supplies it to the adder 10a.

Next, the operation will be explained. The calculation circuit 12 includes an adder 8
The shimging current density is calculated based on the output, the known total length and plate width of the plating electrode, and is supplied to the function generating circuit 13. The function generation list 13 uses the plating current density and the line speed from the detector 2 to generate the plating electrode efficiency EF according to a function f expressed by the following equation, and supplies it to the compensation circuit 14.

Ef = c0f (DF, VF) However, EF... plating electrode efficiency, DF... plating current density, VF... line speed, C... constant.

The compensation circuit 14 multiplies the total current reference corrected by the plating electrode efficiency E used to set the current reference circuit 11 and the line speed vF supplied from the function generation circuit 13 and the t-4 calculation circuit 10. A final correction is made by using the signal, and the resultant signal is supplied to the adder 10a. The operations below the adder 10a are as explained in FIG.

〔Effect of the invention〕

As described above, according to the present invention, plating electrode efficiency is generated as a function of line speed and plating current density,
Since the total current reference is compensated for by K, optimum electrode efficiency control can be obtained and the amount of plating deposited can be kept constant.

[Brief explanation of drawings]

Figure 1 is a block diagram of a conventional automatic plating current control device.
FIG. 2 is a block diagram of an automatic plating control device according to an embodiment of the present invention. 1... Strip, 2.4a-4d... Detector, 3
a to 3d...Metsuki cell, 53 to 5d...rectifier,
63-6d...Controller, 7a-7d...Distributor, 8.108...Adder, 9...PI controller, 10.12...Calculation circuit, 11...Current reference circuit, 13...Function generation circuit, 14...Compensation circuit. In addition, in the figures, the same reference numerals indicate the same parts. Procedural amendment (voluntary) Ill "S'-57EI" 9E1 1. Indication of case Japanese Patent Application No. 58-2137712 2. Issue + 1 JI O name fa; Plating current automatic control device 3 Person making the amendment 5, Details subject to amendment Detailed Explanation of the Invention 6 and Statement of Contents of the Amendment are amended as follows.

Claims (1)

[Claims] Each of the plating currents is controlled according to the sum of the plating currents supplied to the plurality of Metsuki cells and a first current reference compensated to obtain a plating current density in a predetermined range corresponding to the line speed of the strip to be plated. In the automatic plating current control device, there is a calculation circuit that calculates the plating current density of the Metsuki cell from the sum of the above plating currents, and a predetermined function that uses the plating current density from this calculation circuit and the above line speed as variables to control the plating electrode. An automatic plating current control device comprising: a function generation circuit for determining efficiency; and a compensation circuit for generating a second current reference by compensating the first current reference based on the plating electrode efficiency.