JP3240898B2 - Control method of continuous plating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling continuous electroplating, which detects a coating weight formed on a strip surface in a plating tank and sets the coating weight to a target coating weight. The present invention relates to a current control method for a plating bath.

[0002]

2. Description of the Related Art Conventionally, as a current control method for a plating bath of this type, there is a plating current control method disclosed in Japanese Patent Application Laid-Open No. 6-41795.

In this method, a strip from a strip insertion point of a plating tank to a plating adhesion amount detection point is tracked at a predetermined length pitch, a strip width W, a line speed V, and a total plating current It, and the tracking data is obtained. And the instantaneous value CW _{1 of the} actual adhesion amount and the average value CW _{3 of the} adhesion amount in the width direction, the instantaneous plating cathode efficiency η ₁ and the average plating cathode efficiency η ₃ are obtained from the following equations (3) and (1), and The instantaneous value plating cathode efficiency η ₁ and the average value plating cathode efficiency η ₃ are calculated as N, and among the calculation results, the minimum cathode efficiency η _{1 mIN} , η of the minimum value of the efficiency η ₁ and the efficiency η _{3
For applications} where _{3 mIN} is selected _individually and the guarantee of the coating weight after plating is strictly required, the total plating current set value Ip is calculated by the following equation (4).
For applications in which it is only necessary to ensure the average coating weight in the width direction of the strip to guarantee the coating weight after the plating process (hereinafter referred to as “guaranteed average value of multiple points in the width direction”), the following formula (5) is used. The plating current set value Ip of the above is calculated, and the total plating current set value Ip calculated from the above formulas (4) and (5) is given as a set value of the plating current flowing in the current of the plating bath. This is a current control method.

[0004]

(Equation 3)

[0005]

(Equation 4)

[0006]

(Equation 5)

[0007]

(Equation 6)

[0008]

However, the above-described plating current control method has the following problems.

In the case of a product in which the coating weight after plating is guaranteed at an average value of a plurality of points in the width direction, the calculated N efficiency η
By using the minimum value of 3, the amount of adhesion may be over-guaranteed in some cases. Over-guarantee of the adhesion amount as mentioned above occurs,
As a result, the basic unit of current increases, and a non-uniform deposition amount occurs in the longitudinal direction of the strip.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides a method for controlling continuous plating capable of obtaining a uniform deposition amount in the longitudinal direction of a strip and reducing a basic unit of current. With the goal.

[0011]

According to the present invention, a strip to be plated is inserted into a plating bath and run, a plating layer is formed on the surface of the strip, and the plating layer forming strip is pulled out of the plating bath. In the method of detecting the amount of plating on the plating layer forming strip and controlling the current of the plating tank so that the amount of plating becomes the target amount of plating, the amount of coating is detected from the strip insertion point of the plating tank. The strip up to the point is tracked at a predetermined length pitch, the strip width W, the line speed V, and the total plating current It, respectively.
3 obtains the average value plating cathode efficiency eta ₃ of the following formula (1) from, and the cathode efficiency eta ₃ of the plurality of points and the N calculated average cathode efficiency eta _{3 AVE} of cathode efficiency eta ₃ from the calculated value A total plating current set value Ip is calculated by the following equation (2) using a value that satisfies 90 to 110, and the total plating current set value Ip is calculated as the plating current of the plating tank. This is a control method of continuous plating characterized by being provided as a set value.

[0012]

(Equation 7)

[0013]

(Equation 8)

According to the present invention, since the above configuration is used, the average value of the calculated N efficiencies η ₃ is used, and the averaged η _{3 AVE} is set with upper and lower limits, so that the amount of adhesion is constant. , And over-guarantee is reduced.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall system diagram of a continuous electroplating apparatus for implementing the control method of the present invention.

In FIG. 1, reference numeral 1 denotes a plating tank (this embodiment)
In the example, electrogalvanizing) ₁~ 2_nIs to be plated
The electrodes are arranged so as to sandwich a strip as a material.
3₁~ 3_nIs 2₁~ 2_nRectification to apply plating current to
It is a vessel.

The plating current electrode 2 from the rectifier 3 ₁ to 3 _n
1 to 2 _n, the strip 5, the plating solution 6, conductive rolls 4 ₁
And a loop back to the rectifier 3 ₁ to 3 _n through ~4 _{(n +1).} 11 is a dam roll.

The strip 5 plated in the plating tank 1 is run by bridle rolls 7, pulled out of the final plating tank, and its adhesion is measured by an adhesion meter 8.

Here, the processing device 10 is a rectifier 3₁~ 3_n
From each plating current It₁~ It _nThe line control equipment
The sheet width W and the line speed V from the setting 9 and the adhesion amount from the adhesion amount meter 8
Average value of actual results CW_ThreeAnd perform the operation described below.
No, each rectifier 3₁~ 3_nSet the plating current.

FIG. 2 is a flow chart of the operation in the processing device 10 of FIG. The processing device 10 collects the total current actual value It (= ΣIt _i ), the plate thickness W, and the line speed V at a certain pitch of the strip, for example, a pitch of 10 m (S1).

Then, it is determined whether the state is an excessive state during acceleration / deceleration or when the setting of the target adhesion amount CW or the like is changed (S2). If not, the data up to the adhesion amount meter 8 is tracked (S3).

In S2, if it is determined that the state is excessive during acceleration / deceleration or when the setting of the target adhesion amount CW or the like is changed, the data is deleted and is not used (S2).
4).

When the data tracked in S3 reaches the adhesion meter 8, the average cathode efficiency η ₃ is calculated by the equation (1) using the average value CW3 measured by the adhesion meter 8 at that time (S5). It is calculated (S6).

[0025]

(Equation 9)

[0026]

(Equation 10)

The calculated average cathode efficiency η ₃ is always buffered in the latest N pieces of data, for example, 20 pieces of data in the input order. When the new average cathode efficiency η ₃ is newly calculated, 20 pieces of data are obtained. The oldest cathode efficiency is erased and updated.

Further, the average cathode efficiency η _{3 AVE} is determined (S
7). And the average cathode efficiency η _{3 AV E} is 90 or more and 110
It is determined whether or not the data is below (S8). If not, the data is deleted and is not used (S8).
9). The average cathode efficiency η _{3 AVE} is 90 or more and 110
If this is the case, in the case of a product in which the adhesion amount is the average value of a plurality of points in the width direction, the average cathode efficiency η3 calculated from the average value of the adhesion amount
_{Using AVE} , set the total plating current set value I from equation (2).
seeking p (S10), is distributed to each of the rectifier 3 ₁ ~3 _n (S11).

Here, the reason why the average cathode efficiency η _{3 AVE} is limited to 90 or more and 110 or less is that the adhesion amount is excessively or deficient due to local abnormality of the shape or the like (warpage) of the steel plate, and the value outside this range is set. This is because the use of the compound increases the variation in the amount of adhesion. The above processing is performed every time the strip advances 10 m.

According to the method of the present invention, as shown in FIG. 3 (a), in the case of a product in which the adhesion amount is the average value of a plurality of points in the width direction, the average of 20 η ₃ is defined as η _{3 AVE} , _{3 With} the upper and lower limits of _AVE set to 90 and 110, respectively, the total plating current set value is calculated from the above equation (2), and when plating is performed using this Ip, the error with respect to the target adhesion amount in coil units becomes a standard deviation. Halved than before.

(B) is a comparative example according to the prior art. As is clear from FIGS. 3A and 3B, the variation was large in the past, and therefore, +
However, in the present invention, since the variation is small in the present invention, it is sufficient to attach the coating with a minimum height on the + side with respect to the tolerance range of the target amount of adhesion, and the power consumption is about 3
%, And a reduction in zinc basic unit of about 3%.

[0032]

As described above, according to the present invention, it is possible to prevent the adhesion amount from being over-guaranteed, to reduce the uniform adhesion amount in the longitudinal direction of the strip, and to reduce the basic unit of current.

[Brief description of the drawings]

FIG. 1 is an overall system diagram of a continuous electroplating apparatus for implementing a control method of the present invention.

FIG. 2 is a calculation flowchart of the present invention.

FIG. 3 is a diagram illustrating a state of an adhesion amount error with respect to a target adhesion amount according to the present invention.

[Explanation of symbols]

1 plating tank 2 ₁ to 2 _n electrode 3 ₁ to 3 _n rectifier 4 ₁ ~4 _{(n + 1)} conductive rolls 5 strip 6 plating solution 7 bridle roll 8 attached meter 9 line controller 10 processor 11 Damuroru

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C25D 21/12 C25D 7/06

Claims (1)

(57) [Claims] 1. A strip to be plated is inserted into a plating bath and allowed to run, a plating layer is formed on the surface of the strip, and a plating layer forming strip is pulled out of the plating bath, and plating of the plating layer forming strip is performed. In the method of detecting the amount of coating and controlling the current of the plating tank so that the amount of plating becomes the target amount of plating,
The strip width W, the line speed V, and the total plating current It are respectively tracked at a predetermined length pitch from the strip insertion point to the adhesion amount detection point of the plating tank, and the tracking data and the width of the actual adhesion amount are tracked. the average value plating cathode efficiency eta ₃ of the following formula (1) from the direction adhesion amount average CW _3, and the cathode efficiency eta ₃ of the plurality of points and the N calculated, the cathode efficiency eta ₃ from the calculated value
Of the average cathode efficiency η _{3 AVE} of
A total plating current set value Ip is calculated by the following equation (2) using a value satisfying 10 or less, and the total plating current set value Ip is given as a plating current set value of the plating tank. A method for controlling continuous plating, characterized by: (Equation 1) (Equation 2)