JPH0655614A - Device and method for measuring thickness of sheet-shaped component - Google Patents

Abstract

PURPOSE:To find out the thickness of a sheet-shaped component without measurement error by measuring the distance to the surface of the sheet-shaped component on a roll, also measuring the distance to the roll surface and finding the difference between them. CONSTITUTION:A receptor 12 of a transmitting laser type sensor 4 outputs a signal representing the power of the laser beam emitted from a projector 11 proportioned to the laser beam amount passing a slide 12a, and the signal is proportioned to the distance (s) to a knife edge 13 and the surface of a sheet A. An eddy-current type sensor 5 is installed on an installing basket 3 on the position just next to the knife edge 13, and at the time when the sensor is moving, the relative positions of the eddy-current type sensor 5 and the knife edge 13 are not varied. The distance D between the knife edge 13 and the end face of the eddy-current sensor 5 is constant at all times.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thickness measuring device and a thickness measuring method for a sheet-shaped member.

[0002]

2. Description of the Related Art In equipment for manufacturing sheet-shaped members such as sheets and films, sheet-shaped members are continuously manufactured by drawing molten resin from a die. Is controlled so that the thickness of the sheet-shaped member falls within a predetermined range, and in order to control the thickness, it is necessary to measure the thickness of the sheet-shaped member.

Conventionally, this thickness measurement is performed by using a laser sensor provided on a traverse table that is provided so that a sheet-like member that passes through the surface of a rotating roll (also referred to as a base roll) is movable along the width direction. Using it, its thickness was being measured.

For example, when the thickness of a sheet-shaped member is measured by this laser type sensor, in order to improve the measurement accuracy, it is necessary to cancel the variation in the distance between the sensor and the roll when the traverse table is moved. ing.

That is, without the sheet-like member, the traverse table is moved to measure the distance between the sensor and the roll surface, and the measured value is stored in the computer.
When actually measuring the thickness of the sheet-shaped member, the thickness of the sheet-shaped member was obtained by subtracting the above-mentioned measured value stored in the calculator from the actual measured value.

Further, as a laser type measuring method other than the above measuring method, there is a method of measuring the thickness by measuring the amount of laser light passing between the knife edge provided on the side of the traverse and the sheet. is there.

In this measuring method, a laser beam projector is provided on the upstream side (or the downstream side) in the direction orthogonal to the axis of the roll, that is, in the drawing direction of the sheet-shaped member, and the downstream side (upstream side). A gap between the sheet-shaped member surface and the knife edge is measured by arranging a photoreceiver that receives the laser light that has passed between the knife edge and the sheet-shaped member surface through a slit, and measuring the amount of laser light that has passed through the slit. Is a method of measuring the thickness of the sheet-shaped member.

Also in this measuring method, the variation in the distance between the sensor and the roll, which occurs when the traverse is moved, is canceled by the same method as described above.

[0009]

By the way, according to each of the above-described measuring methods, it is possible to cancel the variation in the distance between the sensor and the roll surface, which occurs when the traverse table is moved, but an error due to its reproducibility, that is, the sheet. The problem that the error that occurs because the measurement state when there is no shaped member and the state at the time of actual measurement, and the measurement state that is not always the same each time measurement is performed, cannot be canceled was there.

Therefore, an object of the present invention is to provide a thickness measuring device and a thickness measuring method for a sheet-shaped member which can solve the above problems.

[0011]

In order to solve the above-mentioned problems, the first means of the present invention is a sheet-like member which is moved on a roll rotatably supported in a direction orthogonal to the axis of rotation. Is a thickness measuring device for measuring the thickness of the sheet along the width direction thereof, the moving body that is movable in the width direction along the roll surface, the distance to the surface of the sheet-like member moving on the roll. It is a thickness measuring device for a sheet-shaped member provided with a laser sensor for measuring and an eddy current sensor for measuring a distance to a roll surface.

In order to solve the above-mentioned problems, the second means of the present invention is to set the thickness of a sheet-like member which is moved on a roll supported rotatably in a direction orthogonal to the axis of rotation thereof. A thickness measuring method for measuring along the width direction, up to the surface of a sheet-like member moving on the roll by a laser sensor provided on a movable body that is movable in the width direction along the roll surface. In addition to measuring the distance, the distance to the roll surface is measured by the eddy current sensor provided on the moving body, and the difference between these two measured distances is calculated to measure the thickness of the sheet-shaped member. This is a method for measuring the thickness of a member.

Furthermore, in order to solve the above-mentioned problems, the third means of the present invention is the same as the above-mentioned second means, in which the laser type sensor and the eddy current type sensor are used in the state where the sheet-shaped member is not arranged on the roll in advance. Is a method for measuring the thickness of the sheet-shaped member, in which the initial displacement difference between the two measurement distances is obtained and the initial displacement difference is subtracted from the thickness of the sheet-shaped member obtained by the second means.

[0014]

According to the thickness measuring device and the thickness measuring method for a sheet-shaped member described above, the distance to the surface of the sheet-shaped member on the roll is measured by the laser sensor and the distance to the roll surface is measured by the eddy current sensor. Is measured, and the difference between these two measurement distances is obtained to measure the thickness of the sheet-shaped member without error.

Further, in a state where the sheet-like member is not arranged on the roll in advance, the difference between the measurement distances of the laser type sensor and the eddy current type sensor, that is, the initial displacement difference is obtained in advance,
By subtracting this initial displacement difference from the thickness of the sheet-shaped member obtained on the basis of both sensors, when the moving body moves in the width direction of the roll, its movement path is tilted with respect to the rotation axis of the roll. Even when there is an error, it is possible to cancel the error caused by the inclination of the moving path.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2, reference numeral 1 denotes a roll for guiding a sheet-like member (hereinafter, simply referred to as a sheet) A formed by drawing molten resin from a lip of a die, and is rotatably supported, In addition, a moving body (also referred to as a traverse table) 2 moves along the rotation axis of the roll 1, that is, along the width direction of the sheet A, in the upper portion (side portion or lower portion) of the roll 1. It is provided freely. Of course, the moving body 2 is reciprocally movable by a moving device (a screw mechanism or the like driven by an electric motor) not shown.

A mounting bracket 3 is provided on the movable body 2 above the rotation axis of the roll 1 in parallel with the moving direction of the sheet A. The mounting bracket 3 is mounted on the roll 1. A transmissive laser sensor 4 for measuring the distance to the surface of the sheet A with a laser beam,
An eddy current type sensor 5 for measuring the distance to the surface of the roll 1 is mounted side by side along the axis of rotation of the roll 1.

The transmission type laser sensor 4 is mounted on the upstream side (or the downstream side) of the mounting bracket 3 in the sheet moving direction and also on the downstream side (or the upstream side) of the laser beam projector 11. Laser light receiver 1
2 and a knife edge 13 arranged between the light projector 11 and the light receiver 12 and at the top of the roll 1 to block a part of the laser light a.

A slit 12a having a predetermined width is provided on the light receiver 12 side of the laser light, and the light projector 11 is also provided.
The knife edge 13 has one end (the upper end in this embodiment) in the longitudinal direction of the slit 12a blocked by the knife edge 13 and the other end (the lower end in this embodiment) blocked by the roll 1. Is attached to.

The light receiver 12 of the transmission laser sensor 4
Is the laser beam emitted from the projector 11
It outputs a signal proportional to the amount of laser light that has passed through a (that is, the light transmission area of the slit 12a), and therefore the distance (s) between the knife edge 13 and the surface of the sheet A.
A signal proportional to is output.

The eddy current sensor 5 is mounted on the mounting bracket 3 at a position immediately adjacent to the knife edge 13.
Therefore, the relative positions of the eddy current sensor 5 and the knife edge 13 with respect to each other do not change during the movement thereof. That is, the distance (D) between the knife edge 13 and the end surface of the eddy current sensor 5 is always constant.

Now, the principle of measuring the thickness of the sheet A using the transmission laser sensor 4 and the eddy current sensor 5 will be described. As described above, the eddy current sensor 5 causes the eddy current sensor 5 to move from the surface of the roll 1.
The distance (d) to the measurement end face of is measured.

Therefore, assuming that the thickness of the sheet A is (t), this thickness can be obtained by the following equation. t = D + ds -... Thus, the thickness (t) of the sheet A is calculated from the distance to the surface of the roll 1 obtained based on the value detected by the eddy current sensor 5, and the transmission laser sensor. Since it is obtained by subtracting the distance to the surface of the roll 1 detected by 4, even when the distance between the transmission laser sensor 4 and the roll 1 changes when the moving body 2 is moved, It is always possible to obtain the correct thickness of the sheet A with the change removed.

Of course, although not shown, the above-mentioned sensors 4 and 5 are also provided.
A calculation device for calculating the thickness of the sheet A by inputting a signal from By the way, in the above description, the transmission laser sensor 4 and the eddy current sensor 5 are described as being arranged on a straight line parallel to the axis of the roll A, but the arrangement state of the both is the roll 1. If it is slightly inclined with respect to the rotation axis of
As the sensors 4 and 5 themselves deviate from the initial positions as the sensor moves, there is an error in the distance (s) to the surface of the sheet A and the measurement distance (d) to the surface of the roll 1 by the sensors 4 and 5. Occurs, and thus correction is performed in such a case.

That is, the moving body 2 is moved in the width direction of the roll 1 without the sheet A, and the distances to the surface of the roll 1 are measured by the both sensors 4 and 5, and the both sensors 4 and 5 are measured. The difference between the distances measured by 5 is obtained as an initial displacement difference, that is, an initial error, for example, at predetermined intervals and stored in the arithmetic unit.

Then, when the actual thickness of the sheet A is measured, even if the moving body 2 is subtracted by subtracting a preliminarily obtained initial error from the difference between the distances measured by the sensors 4 and 5.
Even if the movement path of the above is inclined with respect to the rotation axis of the roll 1, the measurement error due to the inclination can be canceled.

Next, a second embodiment of the present invention will be described with reference to FIG. In the first embodiment, the slit 12 provided in the light receiver 12 of the transmission laser sensor 4 is used.
Although a has been described as being provided perpendicularly to the rotation axis of the roll 1 as shown in FIG. 3A, in the second embodiment, as shown in FIG. , Slit 1
2a is inclined at a predetermined angle (θ) with respect to the rotation axis of the roll 1.

As described above, when the slit 12a is tilted, the sensitivity (gain) of measurement is improved as compared with the case where the slit 12 having the same width is not tilted. That is, the slit 1
When 2a is perpendicular to the axis of rotation of the roll 1, the output signal from the light receiver 12 is proportional to the light-transmitting area of the slit 12a of 1 mm x 5 mm, and the total light-shielding state to the whole light-transmitting state is obtained. assuming that 4V changed, position the sheet a on the roll 1, when the thickness is 1mm change area 1mm ²
Change. Therefore, the output signal is 4 × 1/5 =
It will change by 0.8V.

On the other hand, the slit 12a has the roll 1
When the thickness of the sheet A changes by 1 mm when the sheet is tilted at an angle (θ) with respect to the axis of rotation of, the change dV of the output signal is proportional to the light passing area of the slit 12a. Calculated by the formula.

DV = 4 × (1 / sin θ) /5=0.8/sin θ ... From the equation, since θ is smaller than 90 degrees, sin θ becomes a value smaller than 1, and dV> 0. It becomes 8V.

Therefore, a larger output change can be obtained for the same thickness change, and the measurement resolution is improved. That is, the measurement accuracy can be improved.

By the way, in each of the above-mentioned embodiments, the laser type sensor used is a transmissive type which obtains the amount of passing laser light and obtains the distance. However, for example, the reflection time of the laser light is measured to determine the distance. It is also applicable to the case where the required reflection type laser sensor is used.

[0033]

As described above, according to the thickness measuring device and the thickness measuring method of the sheet-shaped member of the present invention, the distance to the surface of the sheet-shaped member on the roll is measured by the laser type sensor, and the eddy current sensor is used. Thus, the distance to the roll surface is measured at the same time, and the thickness of the sheet-shaped member is obtained by calculating the difference between these two measured distances. Unlike the case where the thickness of the sheet-shaped member is obtained by subtraction, the measurement error can be eliminated.

Further, the initial displacement difference between the measurement distances of the laser sensor and the eddy current sensor, that is, the initial error is obtained in advance without arranging the sheet member on the roll, and this initial error is measured by both sensors. By subtracting from the thickness of the sheet-shaped member obtained based on the above, even if the moving path of the moving body to which both sensors are attached is tilted with respect to the rotation axis of the roll, the error due to the tilt is eliminated. You can cancel.

[Brief description of drawings]

FIG. 1 is a schematic side view of a thickness measuring device for a sheet-shaped member according to a first embodiment of the present invention.

FIG. 2 is a view corresponding to the arrow B-B in FIG. 1 showing an arrangement state of each sensor in the first embodiment.

FIG. 3 is a front view of a slit for explaining a method of measuring the thickness of a sheet-shaped member according to a second embodiment of the present invention.

[Explanation of symbols]

 A sheet-like member 1 roll 2 moving body 4 transmission type laser sensor 5 eddy current type sensor 11 light emitter 12 light receiver 13 knife edge

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sakuhiro Sakane 1-4-70 Jomi Chuo-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Industry Co., Ltd.

Claims (3)

[Claims] 1. A thickness measuring device for measuring the thickness of a sheet-shaped member, which is moved on a roll rotatably supported in a direction orthogonal to the axis of rotation of the roll, along the width direction thereof. Provided on the movable body that is movable in the width direction along the surface, a laser sensor for measuring the distance to the surface of the sheet-like member moving on the roll and an eddy current sensor for measuring the distance to the surface of the roll. A thickness-measuring device for a sheet-shaped member. 2. A thickness measuring method for measuring the thickness of a sheet-shaped member, which is moved on a roll rotatably supported in a direction orthogonal to the axis of rotation thereof, along the width direction thereof. A laser sensor provided on a moving body that is movable in the width direction along the surface measures the distance to the surface of the sheet-like member moving on the roll, and the eddy current provided on the moving body. A method for measuring the thickness of a sheet-shaped member, which comprises measuring the distance to the roll surface with a linear sensor and calculating the difference between the two measured distances to measure the thickness of the sheet-shaped member. 3. The method for measuring the thickness of a sheet-shaped member according to claim 2, wherein a difference in initial displacement between the laser-type sensor and the eddy-current-type sensor is not measured in advance when the sheet-shaped member is not placed on the roll. Is calculated and the initial displacement difference is subtracted from the thickness of the sheet-shaped member obtained according to claim 2.