JPS61274768A - Method for controlling thickness of coating film on strip - Google Patents

Abstract

PURPOSE:To make it possible to easily control the thickness of a film in the lateral direction of a strip in reduced equipment cost, by inclining the axis of a squeeze roll in accordance with the bending of said roll. CONSTITUTION:An excessive coating solution is adhered to a running strip 10 from sprays 2 arranged above and below said strip 10 and the excessive solution is removed by a pair of upper and lower squeeze rolls 14A, 14B and the formed coating films are dried and baked in a catenary type baking furnace 16. In this process, the adjustment of a film thickness as a whole is performed by using load detectors 22A, 22B and press-down force control motors 20A, 20B so that the average value of all of film thicknesses detected by film thickness detectors 28A-28C is made constant. Further, the control of the film thickness in the lateral direction corresponding to the difference between the film thickness at the central part and the average film thickness at the edge parts is performed by inclining the axis of the upper squeeze roll 14A to the horizontal direction by chock position determining motors 26A, 26B.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a method for controlling the coating thickness of a strip, and in particular, to a method for controlling the coating thickness of a metal strip uniformly on-line. This invention relates to an improvement in a preferred method for controlling the coating film thickness of a strip, in which an excess coating liquid is applied to the surface of a running strip, and then the excess is removed by a squeeze roll to adjust the coating thickness to a set thickness. □ [Conventional technology] In general, electrical steel sheets used in electric motors, transformers, etc. are coated with insulation, but the coating thickness is coated to a certain level according to customer requirements. It is necessary to control the film within the target range.If the film thickness is too thick, the electromagnetic properties may deteriorate due to a decrease in the space factor, or the welding may occur due to blowholes occurring during welding after lamination. This may result in reduced efficiency or increased costs due to large consumption of coating chemicals.
On the other hand, if the film thickness is too thin, triples such as poor insulation and poor punching properties occur. In addition, it is necessary to uniformly control not only the longitudinal direction of the strip but also the widthwise direction of the strip. However, in the conventional squeeze roll type TengV device, squeeze roll reduction is performed using chocks at both ends of the roll. As a result, the deflection of the squeeze roll caused a film thickness distribution in the width direction of the strip.A roll sheeter method has already been proposed as a method to uniformly cover this film thickness distribution in the width direction. The equipment cost is higher than that of the squeeze roll type, and the width cannot be returned from a narrow width to a wide width, so it is rarely used. (Problem to be Solved by the Invention 1) However, the method of attaching a crown to a squeeze roll core has the problem that it cannot completely respond to changes in coating conditions. In other words, in order to keep the deflection of the squeeze roll constant, it is not possible to significantly change the reduction blade, and therefore, when changing the coating film thickness, the concentration of the coating liquid must be adjusted. However, in order to change the reduction blade by adjusting the spray of the coating liquid, it is necessary to adjust the specific gravity of the coating liquid more than necessary.
- There is a problem that it is necessary to reduce the amount of water, which increases the loss of heat of evaporation of water, leading to an increase in the energy consumption rate. On the other hand, a method of using a squeeze roll iron core as a variable crown roll may also be considered, but this would not only complicate the equipment and increase equipment costs, but also require time and effort to replace the rolls. [Objective of the Invention 1] The present invention has been made to solve the above-mentioned conventional problems. It is an object of the present invention to provide a method for controlling the coating film thickness of a lip. [Means for solving the problem 1] The present invention involves applying an excess coating liquid to the surface of a running strip, and then squeezing out the excess coating liquid. In a method for controlling the coating film thickness of a strip in which the coating thickness is adjusted to a set thickness by removing it with a roll, the film thickness in the width direction of the strip is controlled by tilting the axis according to the deflection of the squeeze roll. Accordingly, the above object has been achieved. In an embodiment of the present invention, the squeeze roll tilting the axis is a squeeze roll on the upper side of the strip. After depositing excess coating liquid on the surface of the strip, remove the excess with a squeeze roll and adjust to the set film thickness. Therefore, the influence of the deflection of the squeeze roll on the thickness in the width direction of the strip is offset, and the film thickness in the width direction can be easily increased with low equipment costs. By using the tilting squeeze roll as the squeeze roll on the upper side of the strip, the strip coated with the coating liquid on the surface is run in the catenary furnace, and the coating film is continuously dried and baked in the catenary furnace. Meandering of the strip can be prevented. [Example] With reference to the drawings below, the application of the strip according to the present invention will be explained.
An embodiment of a metal strip coating equipment employing the A-thickness control method will be described in detail. In this embodiment, as shown in FIG.
The sprayer 12 disposed above and below the strip 10 is used to apply excess coating liquid to the strip 10, and the excess coating liquid adhering to the front and back surfaces of the strip 10 is removed by a pair of squeeze rolls 14A and 14B. It is removed using a horizontal squeeze roll, and then baked in a baking furnace 16 with a catenary set.
The present invention is applied to coating equipment for strips 10 which are dried and baked in a vacuum cleaner. Both ends of the ship's subordinate squeeze roll 14B are rotatably supported by a pair of lower squeeze roll chocks 18A and 18B. This lower squeeze roll chock 18A, 1
8B includes rolling force adjustment motors 20A and 20B for adjusting the rolling blades of the lower squeeze roll 14B, respectively;
Load detector 2 such as a load cell for detecting the rolling blade applied to the lower squeeze roll chocks 18A, 18B
2A122B is installed. Both ends of the upper squeeze roll 14A are rotatably supported by a pair of t-squeeze roll chocks 24A and 24B. Upper squeeze roll chock 24A
, 24B are each pair of chock positioning motors 26A.
, 26B, the left and right chock positions can be changed. On the outlet side of the baking furnace 16, there is a film +1 for detecting the coating film thickness at the center in the width direction and near both ends of the strip surface.
i output devices 28A, 28B, and 28C are provided. The film thickness detectors 28A to 28C all have a known configuration, and the film thickness detector 28A detects the film thickness at the right end in the strip traveling direction, and the film thickness detector 28B detects the film thickness at the center of the strip. The film thickness is detected, and the film thickness at the end portion in the strip advance direction 11 is detected by a film thickness detector 28G. Note that the membrane 1 detectors 28A to 28G may be of individual fixed type as in the example of this embodiment, or may be of a strip type 710.
A single IIA bank ratio detector strip 100 disposed on the surface of the strip 100 may be measured while moving in the width direction. The control device 30 for controlling the squeeze rolls 14A and 14B according to the outputs of the film thickness detectors 28A to 280 includes an average value calculation circuit that calculates the average value of the outputs of the film thickness detectors 28A and 280. 30A and the average value operator circuit 3
a difference calculation circuit 30B that measures the difference between the center film thickness between the 0A output and the film thickness detector 28B output; and the difference calculation circuit 3.
A chock position calculation circuit 30C calculates the chock position of the upper squeeze roll 14A so that the film thickness at the center and end portions is uniform according to the output of 0B; In order to set the left and right upper squeeze roll chocks 24A, 24B at predetermined horizontal positions, the chock positioning motor 2
It mainly includes chock position command circuits 130D and 30E which output commands to 6A and 26B, respectively. Although not shown, the load detectors 22A, 22B and the rolling force adjustment motors 20A, 20B are installed so that the average value of the total film thickness detected by the mw@output devices 28A to 28G is constant.
Of course, the overall film thickness can also be adjusted using . The operation of the embodiment will be explained below. First, the load detectors 22A, 22B and the rolling force adjustment motors 2OA, 2
The overall film thickness has been adjusted using 0B. In this embodiment, furthermore, the film thickness in the width direction is controlled by the chock positioning motors 26A and 26B on the axis of the upper squeeze roll 14A in accordance with the difference between the film thickness at the center and the average film 19 at the ends. It is done by tilting the mind horizontally. Here, the reason why the upper squeeze roll 14A is moved is because if the lower squeeze roll 14B is moved, it has a catenary in the baking furnace 16 after the squeeze roll, so meandering of the strip 10 is likely to occur. It's for a reason. In this way, not only the overall film thickness but also the film thickness distribution in the width direction can be adjusted to be uniform. The end I! is formed by a squeeze roll using a crowned iron core roll proposed by the applicant in Utility Model Application No. 59-143921. The results of uniformly controlling the shore and central portion lI~ and the results of the control according to this example are shown in FIG. 2 in comparison. 1. In FIG. These are control results according to this embodiment. As is clear from the figure, a squeeze roll using a crowned iron core roll cannot cope with large changes in the rolling blade of the coating roll, but this example can sufficiently cope with the change. In the above embodiments, the coating film thickness in the strip width direction was controlled to be uniform, or the method of applying the present invention is not limited to this. It is clear that the method can be applied in a net-like manner even when the distance is large. In addition, in the above embodiment, the present invention is applied to the metal strip in which baking is dried after painting 111! However, the present invention is not limited to this. Effects of the Invention 1 As explained above, according to the present invention, the film Jp in the strip width direction can be easily controlled with low equipment costs and without depending on changes in the rolling blade. Therefore, it has an excellent effect in that it is easy to make the film thickness uniform in the width direction of the strip.

[Brief explanation of the drawing]

FIG. 1 is a perspective view, including a partial block diagram, showing the structure of an embodiment of a coated step tooth of a metal strip, in which the method for controlling the coating VA thickness of a strip according to the present invention is adopted, and FIG. FIG. 3 is a diagram comparing and showing control results according to the embodiment and the conventional example. 10...Squeeze 1~lip, 12...Spray, L4A...Upper squeeze roll, 24A, 24B...Chock for upper squeeze roll, 2
6A, 26B...Chock positioning motor, 28 small, 28B, 28Q...film thickness detector, 30...Fist @1 device.

Claims (2)

[Claims] (1) In a strip coating film thickness control method in which an excess coating liquid is deposited on the surface of a running strip and then the excess is removed by a squeeze roll to adjust the film thickness to a set thickness, the deflection of the squeeze roll A method for controlling the coating film thickness of a strip, characterized in that the film thickness in the width direction of the strip is controlled by tilting the axis according to the width of the strip. (2) The method for controlling the coating film thickness of a strip according to claim 1, wherein the squeeze roll whose axis is tilted is a squeeze roll on the upper side of the strip.