JPH073326B2 - Roll surface crater shape measurement method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for measuring a crater shape on a roll surface.

<Prior Art> Generally, work rolls used for rolling mills such as steel plates, stainless steel plates, and aluminum plates are roughly classified into bright rolls and dull rolls according to their peripheral surface configurations. The former is polished and finished, and the metal plate rolled by this roll has a gloss finish. On the other hand, the latter dull roll
The surface is made uneven by shot blasting or electric discharge machining, and the metal plate rolled by this has a satin finished surface.

By the way, recently, a method using a laser beam to manufacture a dull roll has been attracting attention. This method is, for example, as described in JP-A-55-94790, by pulsing a laser beam by a mechanical chopper while rotating a roll to be processed, or by electrically generating a pulse beam, This is a technique in which the roll surface is partially irradiated with a pulse beam one after another so that the roll surface is partially melted to provide unevenness.

FIG. 4 and FIG. 5 schematically show the roll surface obtained by processing in this way. In the figure,
Reference numeral 1 is a crater formed by one pulse of a laser pulse beam, and reference numeral 2 is a ring portion formed by rising of the molten base metal. Incidentally, 4 is a flat portion where the surface of the roll 3 is left unprocessed.
Further, in this case, the ring portion 2 can be eliminated by adjusting the processing conditions.

The concavo-convex pattern of the surface formed in this way has a characteristic that it is very regular, whereas it is obtained by shot blasting or electric discharge machining is random,
The dull metal sheet rolled by using this laser dull roll has various excellent properties.

<Problems to be Solved by the Invention> Normally, when a roll is dull processed by a laser pulse beam, the size of the craters and the distance between the craters are changed according to the type and application of the metal plate to be rolled. That is, the concavo-convex pattern on the surface is changed by adjusting the output of the laser beam or the irradiation time, or by controlling the rotational speed of the mechanical chopper or the rotational speed of the roll to be processed.

However, there is no effective means for inspecting whether or not the concavo-convex pattern after processing has a predetermined shape, and it is particularly difficult to grasp the size of the crater. That is, the size of the crater is usually about 10 to 400 μm, and the conventional mechanical roughness meter cannot measure because of its large pickup. Also, although there is an optical roughness meter, the roll surface cannot be directly observed because of the large size of the apparatus, and the present situation is that a replica is usually taken for measurement. Further, as a method of directly observing the roll surface, there is a method of using an optical microscope, but there is a disadvantage that the rotation of the roll has to be stopped during that time, which is inefficient and the load on the operator is heavy.

The present invention has been made to solve the above problems, and an object thereof is to provide a crater shape measuring method for a roll surface, which can directly and easily measure the surface shape of a laser-dulled roll. To do.

<Means for Solving Problems> The present invention is a method for measuring a crater shape which is regularly dull-processed in a circumferential direction of a roll surface by a laser beam, and is used for a roll surface rotated at a constant speed. Irradiating a laser beam at a predetermined angle, receiving reflected light from the roll surface at a predetermined angle, comparing the received signal level with a predetermined threshold value and exceeding the threshold value. The step of extracting only the signal with a limiter, the step of measuring the time interval of the signal passing through this limiter, the diameter of the crater is calculated based on the measurement result of this time interval and the roll rotation speed, and the diameter of this crater. The width of the ring portion is calculated based on the above, and the depth of the crater is uniquely obtained based on the relational characteristics between the crater diameter and the crater depth given in advance. A method for measuring a crater shape on a roll surface, the method comprising:

<Operation> According to the present invention, the surface of the roll is continuously irradiated with the laser beam, the intensity of the reflected light is converted into an electric signal, and a small electric signal is regarded as a signal corresponding to the crater portion and cut. By doing so, it is possible to automatically and easily measure the size of the crater and further the size of the flat portion.

<Examples> Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is an explanatory view schematically showing an embodiment of the method of the present invention.

In the figure, 5 is a laser oscillator, and a laser beam 6
Is irradiated onto the surface of the roll 3 at an incident angle θ. During this time, since the roll 3 is rotating in the F direction shown by the arrow, the laser beam 6
Scans in the circumferential direction of the roll 3 (for example, the direction of arrow A in FIG. 4). Reference numeral 8 is a photodetector for detecting the reflected pulse beam 7 reflected on the surface of the roll 3, and outputs an electric signal 9 having a magnitude proportional to the amount of received light. This light receiver 8
Are arranged so that the light receiving angle θ is the same as the incident angle θ of the laser beam 6. Reference numeral 10 denotes a limiter for setting a predetermined threshold value, which cuts signals smaller than the threshold value out of the signals output from the photodetector 8 and passes signals 11 larger than the threshold value. Reference numeral 12 is a timer, which measures the time when there is no signal from the limiter 10 based on the input signal 11. This measurement result is input to the calculator 14 as a signal 13,
Now calculate the size of the crater and use the result as signal 15
Output as.

FIG. 2 shows an example of a signal pattern in each part when the vicinity of the crater 1 on the surface of the roll 3 rotated at a constant speed is measured by using the surface shape measuring device configured as described above.

First, the output pattern of the laser beam 6 emitted from the laser oscillator 5 has a constant value as shown in FIG.
The reflected pulse beam 7 from the surface of the roll 3 is detected by the photodetector 8. The flat portion 4 is formed because the roll 3 is polished and then irradiated with the laser beam 6 to form the crater 1. While the reflectance at 1 is extremely high, the surface of the crater 1 is oxidized and is not flat, so the amount of light received by the light receiver 8 is small, as shown in FIG. 2 (b). The reflected pulse beam 7 is converted into an electric signal 9 by the light receiver 8, and this pattern is the same as that in FIG. 2 (b). Further, the electric signal 9 is cut by a limiter 10 to reduce a low output signal, and the electric signal 9 is shown in FIG.
The pattern is as shown in.

Therefore, the timer 12 starts time measurement when the input signal becomes zero, stops the time measurement when there is an input signal, and outputs the elapsed time T to the calculator 14 as the signal 13.
The timer 12 is reset to prepare for the next measurement.

The calculator 14 performs the following calculation based on the input signal 13.

That is, assuming that the peripheral speed of the roll 3 is v (mm / sec) and the time measured by the timer 12 is T (sec), the crater diameter D (mm) is calculated by the following equation.

D = v · T (1) Note that the ring portion 2 is also included in the crater here.

Also, here, the width of the ring portion 2 is B (mm) (see FIG. 5).
Then, there is a relation of B≈0.15D (2), and if the crater depth is H (mm) (see FIG. 5), the depth H and the diameter D are Since it is known that there is a relation as shown in FIG. 3, the shape of the crater can be grasped if the diameter D of the crater is obtained by the equation (1).

In the above embodiment, the case of measuring the diameter of the crater has been described, but the size of the flat portion can be measured by using the same means. However, in this case, it is necessary to reversely use the pattern shown in FIG. 2C as the trigger signal for starting the timing. That is, the measurement is started when there is an output, and the measurement is ended when the output becomes zero.

As the laser beam source for measurement, a part of the laser beam for dull processing may be extracted and used.

Further, the timer 12 does not have to be provided separately, and may be built in the arithmetic unit 14.

<Effects of the Invention> As described above, according to the present invention, the surface shape of a dull-processed roll can be easily measured by using a laser beam, and automation of the measurement can be achieved. Therefore, it greatly contributes to product quality assurance.

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing an embodiment of the method of the present invention,
FIG. 2 is a characteristic diagram showing each signal pattern, FIG. 3 is a characteristic diagram showing the relationship between the diameter and depth of the crater, FIG. 4 is a plan view schematically showing the roll surface, and FIG. FIG. 3 is a cross-sectional view schematically showing the roll surface. 1 ... Crater, 2 ... Ring part, 3 ... Roll, 4 ... Flat part, 5 ... Laser oscillator, 6 ... Laser beam, 7 ... Reflected pulse beam, 8 ... Photoreceiver, 9 ... Electrical signal, 10 ... Limiter, 11, 13,15 ... Signal, 12 ... Timer, 14 ... Calculator

Claims (1)

[Claims] 1. A method for measuring a crater shape which is regularly dull-processed in the circumferential direction of a roll surface by a laser beam, wherein the roll surface rotated at a constant speed is irradiated with the laser beam at a predetermined angle. A step, a step of receiving the reflected light from the roll surface at a predetermined angle, a step of comparing the received signal level with a predetermined threshold value, and extracting only a signal exceeding the threshold value with a limiter The step of measuring the time interval of the signal passing through the limiter, the diameter of the crater is calculated based on the measurement result of the time interval and the roll rotation speed, and the width of the ring portion is calculated based on the diameter of the crater. And a step of uniquely calculating the depth of the crater based on a predetermined relational characteristic between the crater diameter and the crater depth. Crater shape measuring method of the roll surface to.