JPH04188009A - Thickness measurement method and device for cylindrical material - Google Patents

Abstract

PURPOSE:To precisely measure the thickness of a ceramic-made long cylindrical material by fixing laser sensors on the edge parts of two long rodlike measurement arms to use respectively. CONSTITUTION:A first laser sensor 12 is arranged on a vertical line through a center axis 35 of a material 34 to be measured while a second laser sensor 14 is set on the same vertical line of the material 34 to be measured. A measurement point 37 of the inner circumferential face of the material 34 to be measured is detected by a first laser sensor 12 and the distance l1 between the first laser sensor 12 and the measurement point 37 of the inner circumferential face is measured while a measurement point 38 of the outer peripheral face of the material 34 to be measured is detected by the second laser sensor 14 to measure the other distance between the second laser sensor 14 and the measurement point 38 of the outer peripheral face. The thickness (t) of the material 34 to be measured is calculated by subtracting said measurement values l1, l2 from the absolute distance L between the first and the second laser sensors previously measured.

Description

[Detailed description of the invention] C Industrial application field] The present invention relates to a soaking tube used in a semiconductor diffusion process.

Regarding the wall thickness measuring method and wall thickness measuring device of a cylindrical object suitably used for measuring the wall thickness of a ceramic cylindrical object such as a reaction tube, in more detail, it is a long cylindrical object and The present invention also relates to a wall thickness measuring method and a wall thickness measuring device for a cylindrical object, which can accurately measure the wall thickness at any point from the end to the deep penetration part.

[Conventional technology]

Conventionally, the wall thickness of long cylindrical objects has been measured using ultrasonic waves, but in materials such as ceramics, which have an extremely high Young's modulus, the speed of sound is high, making it difficult to separate the incident wave from the reflected wave. In practice, it is impossible to measure the wall thickness of a cylindrical object made of a material such as a difficult material or a composite material that causes diffuse reflection or absorption of ultrasonic waves due to a difference in composition within the material using ultrasonic waves. For this reason, for cylindrical objects whose wall thickness cannot be measured using ultrasonic waves, measuring the wall thickness at both ends with a micrometer or caliper is enough to measure the depth of the wall, which is difficult to reach with a micrometer or caliper. No wall thickness measurements were taken.

[Problems to be Solved by the Invention] However, for ceramic soaking tubes, reaction tubes, etc. used in the semiconductor manufacturing field, there are increasing demands for diversification of product shapes and uniformity of wall thickness. For quality assurance purposes, there is an increasing need to measure wall thickness not only at both ends but also at deep penetration parts.

For this reason, even for long cylindrical objects made of materials such as ceramics and composite materials that cannot be measured using ultrasonic waves, we have developed a wall thickness measurement method and wall thickness that can measure the wall thickness at the deep penetration part. Development of a thickness measuring device is desired.

The present invention was made in view of the above circumstances, and it is an object of the present invention to accurately measure the wall thickness at any part of a long ceramic cylinder such as a soaking tube or a reaction tube for a semiconductor diffusion furnace. An object of the present invention is to provide a method and apparatus for measuring the wall thickness of a cylindrical object.

[Means to solve the problem]

In order to achieve the above object, the inventors of the present invention have conducted intensive studies, and as a result, have arranged a pair of laser sensors inside and outside of a cylindrical object to be measured. By measuring the distance to the surrounding wall surface and subtracting the sum of these measured values from the absolute distance between both laser sensors, it is possible to accurately measure the wall thickness of the object to be measured, even if it is made of ceramics, composite materials, etc. The above laser sensors can be fixed to the tips of two long bar-shaped measuring arms arranged horizontally at a predetermined distance apart from each other, so that a pair of laser sensors can be placed at the same position. The laser sensor is placed on a vertical line, and the tip side of one measuring arm is inserted into the cylindrical object to be measured along the axial direction, and one laser sensor is placed inside the object to be measured, and the other laser sensor is placed inside the object to be measured. By placing a pair of laser sensors outside the object to be measured, even if the object is a long cylinder, a pair of laser sensors can be placed in the deep part of the object on the same vertical line with the peripheral wall of the object in between. The inventors have discovered that they can be arranged so as to face each other, and therefore the wall thickness of a long, cylindrical object to be measured can be accurately measured even at a deep penetration part, leading to the present invention.

Therefore, the present invention has a first measuring arm in the form of a long rod, the tip of which is fixed with a second laser sensor that detects the inner circumferential surface of the cylindrical object to be measured, and the tip of which is fixed to the outer circumferential surface of the object to be measured. along the horizontal direction so that the first and second laser sensors are located on the same vertical line with a second measurement arm in the form of a long rod fixed to a second laser sensor that detects the and inserting the distal end side of the first measurement arm into the cylindrical object to be measured along the axial direction to place the first laser sensor inside the object to be measured, and the second laser sensor. A first laser sensor is placed on the outside of the object to be measured, and a first laser sensor measures the distance between the first laser sensor and the inner circumferential surface of the object, and a second laser sensor measures the distance between the second laser sensor and the outer circumferential surface of the object. A method for measuring the wall thickness of a cylindrical object, characterized by measuring the distance between the two laser sensors and calculating the wall thickness of the object from these measured values and the absolute distance between the two laser sensors, and supporting the proximal end of the object. By supporting the long rod-shaped first measuring arm arranged horizontally, and by supporting the base end, the first measuring arm is arranged horizontally.
a second measurement arm in the form of an elongated bar placed horizontally at a predetermined distance from the measurement arm; and a second measurement arm fixed to the tip of the first measurement arm to detect the inner circumferential surface of the cylindrical object to be measured. 1
a laser sensor, a second laser sensor fixed to the tip of the second measurement arm and configured to detect the outer peripheral surface of the object to be measured, which is arranged on the same vertical line as the first laser sensor; A roller for rotatably supporting the object to be measured is disposed, and the roller is equipped with a cart that supports the object to be measured and is movable along the axial direction of the object. The object to be measured is rotatably placed on the rollers of the cart, and the cart is moved along the axial direction of the object to measure the thickness of the object at the first point.
and a second laser sensor, the first laser sensor measures the distance between the first laser sensor and the inner peripheral surface of the object to be measured, and the second laser sensor measures the distance between the second laser sensor and the outer peripheral surface of the object to be measured. Provided is a wall thickness measuring device for a cylindrical object, characterized in that the device is configured to measure the distance between the two laser sensors, and calculate the wall thickness of the object from these measured values and the absolute distance between both laser sensors. .

Here, when the first and second laser sensors are fixed to the distal ends of two long bar-shaped measurement arms that are arranged horizontally with a predetermined distance from each other by supporting their base ends, Since the measuring arm is in the shape of a long rod, the measuring arm may warp due to its own weight, causing the first and second laser sensors to deviate from the same vertical line and not facing each other accurately. In such a case, by attaching a weight balancer (weight) to the tip of both or one of the measuring arms and adjusting the degree of warpage, it is easy to position the measuring arms at a predetermined distance on the same vertical line. It can be corrected.

Further, the calculation operation for calculating the wall thickness of the object to be measured from the measured values by the first and second laser sensors and the distance between both laser sensors may be automatically performed using an appropriate calculation device. Furthermore, in the above measurement device, the rotation of the object to be measured and the movement of the cart are automatically performed using a drive motor that rotates and moves the roller and cart that support the object to be processed, respectively, and a computer that controls the drive motor. You can also do it in a specific manner.

[For production]

The method and device for measuring the thickness of a cylindrical object according to the present invention includes disposing a pair of laser sensors on the inside and outside of the cylindrical object so as to face each other across the circumferential wall of the object. Measure the distance from each laser sensor to the surrounding wall,
The thickness of the peripheral wall of the object to be measured is calculated from these measured values and the absolute distance between both laser sensors.

In this case, according to the measuring method and device of the present invention, since a laser sensor is used, the wall thickness can be measured satisfactorily even if the object to be measured is a ceramic or a composite.
In addition, a first laser sensor that detects the inner circumferential surface of the cylindrical object to be measured and a second laser sensor that detects the outer circumferential surface of the object to be measured are connected to the first and second long rod-shaped measurement arms, respectively. the first and second measuring arms are spaced apart from each other by a predetermined distance along the horizontal direction so that the first and second laser sensors are arranged on the same vertical line with a predetermined distance from each other. The tip side of the first measurement arm is inserted into the cylindrical object to be measured along the axial direction to place the first laser sensor inside the object to be measured, and the second laser sensor is placed inside the object to be measured. Since it is configured to be placed on the outside of the object, even if the object to be measured is long and cylindrical, both the first and second laser sensors can be placed on either side of the object, facing each other across the peripheral wall. Therefore, it is possible to accurately measure the wall thickness even in a deep part of a long cylindrical object. Furthermore, by rotating the object to be measured and moving it along its axial direction, the thickness of a desired portion of the object to be measured can be easily measured.

Furthermore, in the apparatus of the present invention, the cart supporting the object to be measured is movable along the axial direction of the object to be measured, and the object to be measured is supported by a plurality of objects arranged on the upper part of the cart. Since it is placed on a roller, the measurement point can be easily moved.Furthermore, by combining the drive motor and computer to rotate and move the roller and cart, the measurement point can be moved easily. Movement can be done automatically.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

〔Example〕

1 to 3 show an apparatus for measuring the wall thickness of a cylindrical object according to an embodiment of the present invention. It is suitably used to measure the wall thickness of a cylindrical object made of material.

This wall thickness measuring device includes a long rectangular base 1. At the center of one end of the base 1 in the width direction, there is a pedestal 2 fixed to the base 1, and a pedestal 2 is erected at a predetermined distance from each other along the length of the base 1. two pillars 3
, 3, and a thick plate-shaped stop plate 4 installed between the upper ends of the pillars 3, 3. Further, in the figure, reference numerals 6 and 7 are square block-shaped first and second arm supports arranged at a predetermined distance from each other. The stand body 5 is connected and fixed.
It is supported by the pillar 3.3 so as to be movable in the vertical direction.

The first and second arm supports 6 and 7 are moved by operating the lifting handle 9 and by the action of a drive gear (not shown) connected to the handle 9 and a guide gear IO meshing with the drive gear (not shown). It is designed to move up and down along the column 3.3.

In the figure, reference numeral 11 denotes a first measurement arm in the shape of a long rectangular bar made of a lightweight and high-rigidity material such as hard plastic or aluminum, and the base end of the first measurement arm 11 supports the first arm. The body is fitted and fixed into a support hole (not shown) drilled in one end face in the longitudinal direction and supported in a horizontal state, and a hole at the tip of the body is fitted to detect the inner peripheral surface of the object to be measured. 2 laser sensors 12 are fixed with their working surfaces facing upward. In addition, 13 in the figure is a long rectangular rod-shaped 211II made of the same material as the first measuring arm 11.
The base end of the arm is fitted and fixed into a support hole (not shown) drilled in one end face in the length direction of the second arm support 7, and the base end thereof is fixed to the upper part of the first measurement arm. They are spaced apart by a predetermined distance and are arranged and fixed along the horizontal direction. A second laser sensor 14 for detecting the outer peripheral surface of the object to be measured is fixed at the tip of the second measurement arm 13 with its working surface facing downward, and the first laser sensor 12 and this second laser Exists on the same vertical line as the sensor 14,
The respective working surfaces are arranged so as to face each other.゛Here, the first laser sensor 12 and the second laser sensor 14 are single-piece measuring arms 11.
．． 13 may not be able to be arranged on the same vertical line. That is, the laser sensor 12
．． Since the measuring arms 11 and 13 that support the laser sensors 12 and 24 are long rod-shaped, they may warp due to their own weight or the weight of the sensor, and both laser sensors 12 and 14 may deviate from the same vertical line. Therefore, in such a case, by attaching a weight balancer (weight) to both or one of the first and second laser and laser sensors 12.14 and adjusting the degree of warpage, both laser sensors 12.
14 are located on the same vertical line. Furthermore, the first and second laser sensors 12.14 can be attached to the first and second measurement arms 11.13 via appropriate dampers, thereby preventing small vibrations or vibrations of the arms 11.13. It can be absorbed and support the sensor more stably.

In the figure, reference numeral 15 denotes a trolley on which the object to be measured is placed. It is designed to be movable. This trolley 15 includes a pair of frame-shaped bases 174
The lower end surfaces of the substrates 17 and 7 are connected to each other by a substantially square bottom wall plate 18, and both ends of the upper end surfaces of these base bodies 17 and 17 are connected to each other by plate-like connecting plates 19 and 19. A cylindrical slip roller 21 is disposed on the upper end surface of the base body 17, 17 and is rotatably supported by bearings 20, 20 at both ends in the length direction, and is rotatable by bearings 22, 22. A drum-shaped drive roller 23 supported on the roller is disposed. Note that each drive roller 23 is configured to simultaneously rotate and stop in the same direction by a roller drive stepping motor (not shown).

Further, the bottom wall plate 18 of this truck 15 has guide grooves 24 and 24 formed along its length by bulging out in the vicinity of both end portions to have a convex cross section. Wheels 24a, 24a are disposed to engage with a rail 16°16 having a convex cross section and laid along the length direction on the upper surface of the base 1, and these wheels 24a,
24a, the trolley 15 moves on the rail 16°16 to the base 1.
It is designed to be able to move smoothly along its length. Further, on the upper surface of the bottom wall plate 18, a sensor moving rail 25 with a convex cross section is laid along the length direction at the center in the width direction, and this rail 25 has a U-shaped cross section. A sensor support body 28 consisting of a base body 26 and a support plate 27 erected on the upper surface of the base body 26 is arranged such that a recess 29 on the lower surface side of the base body 26 and a protrusion of the rail 25 are slidably engaged. A warpage measuring laser sensor 29 for detecting the outer peripheral surface of the object to be measured is attached to one side of the support plate 27 of the sensor support 28 with its working surface facing upward. Note that this sensor support 28
is automatically moved along the rail 25 on the bottom wall of the trolley 15 by a stepping motor (not shown) for the warpage measurement laser sensor slide, and the trolley 15 is also moved by a stepping motor (not shown) for moving the trolley. (not shown) automatically moves on the rails 16 of the base 1.

This thickness measuring device is the first laser sensor.

The first laser sensor 9 digitizes and calculates the detection signal from the warp measurement laser sensor, and controls the starting and stopping of the stepping motor for driving the roller, the stepping motor for sliding the laser sensor for warp measurement, and the stepping motor for moving the cart. It is configured to perform this automatically using a control sequencer, and its control system is configured as shown in FIG.

That is, 30 in FIG. 4 sets the desired measurement point of the object to be measured, and the respective laser sensors 12, 13° 29
31 is a line computer that calculates the wall thickness and degree of warpage by calculating the measured values by ) respectively start and stop, and each laser sensor 12,
This is a control sequencer that controls the operation of 13.29.

Each motor 32a by this sequencer 31,
32b, 32c are controlled by driver units 33a, 3
3b, 33c, and each laser sensor 12, 14.29 is controlled by the digital meter relay 3.
4 and controllers 12a, 14a, and 29a, respectively.

To explain this control system in more detail, first, a desired measurement point of the object to be measured is set in the line computer 30, and this is converted into an electric signal and sent to the control sequencer 3.
1, and the sequencer 31 controls each drive motor 32a, 32b via driver units 33a, 33b, 33c in response to this electrical signal.

32c are respectively driven, and each drive motor 33a, 33b, 33c is stopped when it has rotated by a predetermined amount according to the electric signal. After each motor has stopped, a signal is output from the sequencer 31 to the digital meter relay 34, and the switch of the relay 34 is turned on, causing each controller 12a to be turned on.

14a, 29a via the first laser sensor 12. The second laser sensor 141 and the laser sensor 29 for warp measurement operate to detect each measurement surface, and the detection signal is sent to the sequencer 32 via each controller 12a, 14a, 29a and digital meter relay 34, which is These signals are input to the line computer 30, and the computer 30 converts these signals into numerical values, which calculates and displays the measured values of the thickness and warpage of the object to be measured. Furthermore, it is configured such that these measured values can be printed out via a printer 34 if necessary.

When measuring the wall thickness of a cylindrical object using this wall thickness measuring device, first move the trolley 15 to the rear side of the base l (opposite side to the stand body 5), and then each roller 21 of the trolley 15 ．．
, 22 along the length direction of the trolley 15, move the trolley 15 forward (toward the stand body 5 side), and set the tip of the first measuring arm 11 on the heel, 11j. The first laser sensor 12 is inserted into the object 34 from one end side.
is placed on the vertical line 36 passing through the central axis 35 of the object to be measured 34, and the second laser sensor 14 is placed on the object to be measured 34.
They are placed on the same vertical line 36 outside. At this time, the lift handle 9 is operated to move the arm support 6.7 up and down appropriately according to the diameter of the fixed object 34, and the 11111 constant arm 11
Insert the distal end side into the object to be measured 34. Also, trolley J5
is moved along the length of the base 1, the drive roller 23 is rotated to rotate the object to be measured, and both laser sensors 12 and 14 are placed at desired positions on the object to be measured 34. Note that these positioning operations are automatically performed by setting measurement positions in the computer 30.

Next, after stopping the rotation of the object to be measured 34 and the movement of the cart 15 and fixing the object to be measured 34, the second laser sensor 1
2 detects the measurement point 37 on the inner circumferential surface of the object to be measured 34 and measures the distance p1 between the second laser sensor 12 and the measurement point 37 on the inner circumferential surface. The distance between the second laser sensor 14 and the measurement point 38 on the outer circumferential surface is detected by detecting the measurement point 38 on the outer circumferential surface of 34! Measure 2. Then, the above measurement value is obtained from the absolute distance between the first and second laser sensors, which has been measured in advance! ■ and C
By subtracting 2, the wall thickness t of the object to be measured 34 is calculated. Note that the activation and stopping of these laser sensors, the digitization and calculation of each measured value are automatically performed by the above-mentioned control system. Furthermore, in this case, by setting a plurality of fixed points in the computer 30, the control system controls the drive and stop of the drive roller 22, the movement of the trolley 15, and the operation and stop of the first and second laser sensors. Thus, wall thickness measurements at a plurality of measurement points can be performed continuously.

Further, the apparatus of this embodiment can measure the warpage and distortion of the object to be measured 34 at the same time as the thickness measurement described above. That is, after the rotation of the object to be measured 34 due to the driving of the drive roller 22 has stopped, the sensor support 2 is moved while the outer circumferential surface 39 of the object to be measured 34 is detected by the laser sensor 29 for measuring warpage.
8 on the sensor moving rail 25 from one end to the other, and the laser sensor 29 continuously or intermittently detects the outer peripheral surface of the object 34 along the axial direction. The distance p3 between the laser sensor 29 and the outer peripheral surface 39 of the object to be measured 34 is measured continuously or intermittently along the axial direction of the object to be measured 34 from one end to the other end, and from the change in the measured value. Measure the presence or extent of warpage or distortion. In this warpage measurement as well, the movement of the sensor support 28, the operation of the radar sensor 29 for warp measurement, the digitization of the measured value, etc. are automatically performed by the above-mentioned control system.

According to the method for measuring wall thickness and warpage using this wall N measuring device, since the wall thickness and warpage are measured using a laser sensor, good measurements can be made even if the object to be measured is a ceramic or a composite. be able to. Further, the first and second laser sensors 12.14 are arranged in the form of long rods, spaced apart from each other by a predetermined distance, and arranged along the horizontal direction.
The first measuring arm 11 is fixed to the distal ends of the first measuring arms 11 and 13, respectively, and is arranged and fixed so as to be located on the same vertical line, and the distal end side of the first measuring arm 11 is inserted into the cylindrical object to be measured. By arranging the first laser sensor 12 inside the object to be measured and arranging the second laser sensor 14 outside the object, both the first and second laser sensors 12 and 14 are placed on the peripheral wall of the object to be measured. Even if the object to be measured is a long cylindrical object, the first and The second laser sensors can be reliably arranged opposite to each other with the circumferential wall of the object to be measured interposed therebetween, making it possible to accurately measure the wall thickness.

In this case, the first and second laser sensors can be easily positioned by rotating the object to be measured on the cart 15 and moving the cart I5. Rotation and trolley 1
By automatically controlling the movement of 5 by the control system, the positioning operation of both the first and second laser sensors can be performed automatically. Furthermore, the wall thickness measuring device of this embodiment can measure not only the wall thickness of the object to be measured, but also the presence or extent of warpage or distortion.

Next, an experimental example will be shown.

[Experimental Example 1] Using the apparatus shown in Figs.
, d) was measured and compared with the actual value measured by a micrometer at the same measurement point to determine the error rate.

The results are shown in Table 1.

Table 1 As shown in Table 1, it was confirmed that the measurement results obtained by the above-mentioned wall thickness measuring device had an accuracy that would cause no problem in practical use.

(Experimental Example 2) Using the apparatus shown in FIGS. 1 to 4 above, one end opening of the ceramic bottomed cylindrical object B having a length of 2500 mm and an outer diameter of 350 mm shown in FIG. 400mm more
point (point a), 800 mm point (point b), 1200 mm
The wall thickness was measured at each measurement point: mm point (0 point), 1600 mm point (d point), and 2000 mm point (e point). The results are shown in Table 2.

As shown in Table 2, according to the wall thickness measuring device of the above embodiment, even if the object is a long cylindrical object, good wall thickness measurement can be performed at the deep part of the object.

Note that the wall thickness measuring method and the wall thickness measuring device of the present invention are not limited to the above embodiments. For example, in the wall thickness measuring device, in the above embodiments, the first Although the configuration is configured such that the positioning operations of the second laser sensor and the second laser sensor are automatically performed using a control system using a computer, it is also possible to perform these operations manually. Various changes may be made without departing from the gist of the invention.

(Effects of the Invention) As explained above, according to the wall thickness measuring method and wall thickness measuring device of the present invention, even if it is a ceramic elongated cylindrical object,
The wall thickness at any of the locations can be measured satisfactorily.

[Brief explanation of drawings]

1 to 3 show a wall thickness measuring device according to an embodiment of the present invention, in which FIG. 1 is a plan view, FIG. 2 is a side view,
FIG. 3 is a sectional view taken along the line ■-■ in FIG. 1, FIG. 4 is a schematic diagram showing the control system of the device, and FIG. 5(A). (B) shows the object to be measured used in Experimental Example 1, and (A
) is a front view, (B) is a cross-sectional view taken along the line B in FIG. 13 (A), and FIG. 6 is a cross-sectional view showing the object to be measured used in Experimental Example 2. 11-First measurement arm 12...Second laser sensor 13 Second measurement arm 14-Second laser sensor 15 Vehicle 21 - Slip roller 2
3. Drive roller 34...Object to be measured Fig. 3 Fig. 4

Claims (1)

[Claims] 1. A first measurement arm in the form of a long rod, to which a first laser sensor for detecting the inner circumferential surface of a cylindrical object to be measured is fixed at its tip; A second measuring arm in the form of a long rod to which a second laser sensor for detecting the outer peripheral surface is fixed is spaced apart from each other by a predetermined distance so that the first and second laser sensors are positioned horizontally on the same vertical line. The distal end side of the first measurement arm is inserted along the axial direction into the cylindrical object to be measured to place the first laser sensor inside the object to be measured, and the second laser sensor is placed along the object to be measured. A sensor is placed outside the object to be measured, and a first laser sensor measures the distance between the first laser sensor and the inner peripheral surface of the object, and a second laser sensor measures the distance between the second laser sensor and the object to be measured. A method for measuring the thickness of a cylindrical object, characterized by measuring the distance to the outer peripheral surface and calculating the thickness of the object from these measured values and the absolute distance between both laser sensors. 2. A long rod-shaped first measurement arm that is arranged horizontally by supporting its base end; and a first measurement arm that is arranged horizontally with a predetermined distance from the first measurement arm by supporting its base end. a second measuring arm in the form of a long rod; a first laser sensor fixed to the tip of the first measuring arm to detect the inner circumferential surface of the cylindrical object to be measured; and a tip of the second measuring arm. A second laser sensor is fixed to the cylindrical object and detects the outer circumferential surface of the object to be measured, which is arranged on the same vertical line as the first laser sensor, and a roller for rotatably supporting the cylindrical object to be measured is disposed on the upper part. and a cart that supports the object to be measured on the rollers and is movable along the axial direction of the object, so that the cylindrical object to be measured can be rotated on the rollers of the cart. By moving the trolley along the axial direction of the object to be measured, the wall thickness measurement points of the object to be measured correspond to the first and second laser sensors, and the first laser sensor is used to measure the thickness of the object. and the inner peripheral surface of the object to be measured, and also measure the distance between the second laser sensor and the outer peripheral surface of the object to be measured using a second laser sensor, and calculate the absolute distance between these measured values and the two laser sensors. A wall thickness measuring device for a cylindrical object, characterized in that the device is configured to calculate the wall thickness of the object to be measured from