JPS6347609A - Shape inspection apparatus - Google Patents

Abstract

PURPOSE:To measure a shape in a stable state with high accuracy, by detecting an article to be measured on an inspection stand to drive an ultrasonic transmitter-receiver after a definite time and measuring the distance up to the article to be measured by an ultrasonic distance measuring device. CONSTITUTION:An article 3 to be measured is placed on an inspection stand 1 formed into the same shape as a normal article 3 to be measured and, after this state is detected by a detection sensor 8, an ultrasonic distance measuring device 9 is started by operating a control part 10 after 10sec and each ultrasonic transmitter-receiver 4 transmits and receives an ultrasonic wave to detect the distance from the surface of the stand 1 to the article 3 to be measured. The measured value of each transmitter-receiver due to temp. change is compensated by a transmitter-receiver 4c, a temp. sensor 7 and an operational processing part 12. Since the article to be measured is high temp., the shape of said article to be measured is measured in a stable state delayed by about 10sec and measurement is repeated several times while each transmitter-receiver is changed over by the measuring device 9 and the shape judging accuracy of the article to be measured can be enhanced using the average value of the measured values.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is capable of changing the shape of a workpiece molded at high temperature, such as glass or plastic, without allowing time for it to cool down to room temperature. This invention relates to a shape inspection device for inspecting (measuring).

2. Description of the Related Art Recently, ultrasonic distance measuring devices and optical distance meters have come into widespread use for inspecting the distance and shape of an object. These are usually used for objects to be measured at room temperature. On the other hand, there is an increasing desire to measure the shape of objects molded at high temperatures, such as glass and plastics, while they remain at high temperatures. By the way, in an ultrasonic distance measuring device, the shape is measured by the round trip propagation time of the ultrasonic waves between the ultrasonic transducer and the object to be measured and the propagation speed of the ultrasonic waves, but when the object to be measured is in a high temperature state, The ultrasonic propagation speed changes, making it impossible to measure accurate shapes.

Therefore, in conventional ultrasonic distance measuring devices, for example,
As described in Publication No. 361, etc., a configuration is known in which an ultrasonic receiver for sound speed correction is used as a means for correcting changes in sound speed due to temperature changes to improve distance measurement accuracy. There is.

Problems to be Solved by the Invention However, in the configuration of the conventional example described above, the atmosphere is not stable immediately after installing a high-temperature object to be measured, and there is a temperature distribution in the ultrasonic propagation path to the object to be measured. There has been a problem that distance measurement, that is, shape measurement cannot be performed with high accuracy due to the following reasons. In addition, conventional optical rangefinders inherently have poor distance measurement accuracy when measuring objects that are transparent such as glass or plastic, making it difficult to apply them not only to high-temperature objects. there were.

SUMMARY OF THE INVENTION Therefore, the present invention aims to provide a shape inspection device that can improve the accuracy of shape measurement by installing a high-temperature object to be measured and performing measurement in a stable atmosphere after a certain period of time has elapsed. It is something.

Means for solving the problems and the technical means of the present invention for solving the above-mentioned problems include an inspection table on which an object to be measured is installed at a predetermined position, and a plurality of superstructures attached to this inspection table. a sonic transducer; a detection sensor that detects that the object to be measured is placed on the inspection table; and a delay unit that drives the ultrasonic transducer after a certain period of time has elapsed from the output of the detection sensor. ,
It is equipped with an ultrasonic distance measuring device connected to the ultrasonic transducer.

For production The effects of the above technical means are as follows.

In other words, the detection sensor detects that a high-temperature object is placed on the inspection table, and after a predetermined period of time has elapsed for the atmosphere to stabilize using the delay unit, the ultrasonic transducer is activated to emit ultrasonic waves. Using the propagation time of transmitted and received waves and the propagation speed of the ultrasonic waves, an ultrasonic distance measuring device measures the distance to the object to be measured, thereby making it possible to measure (inspect) the shape of the object. Since shape measurement is performed after such an atmosphere is stabilized, accuracy can be improved.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. The figure is an explanatory diagram of a shape inspection device in an embodiment of the present invention.

In the figure, 1 is a detection stand, and there are spacers 2 at multiple locations on the surface.
have. Reference numeral 3 denotes a high temperature object to be measured, which is placed on the spacer 2 of the inspection table 1. In the illustrated example, the object to be measured 3 is formed in a curved shape like a windshield, so the surface of the inspection table 1 is formed in the same curved shape as the normal object to be measured 3, and the object to be measured 3 is The spacer 2 maintains a constant distance from the surface of the inspection table 10, for example, about 3 inches. 4a,
4b, 4c, . . . , 4n are ultrasonic transducers that transmit and receive ultrasonic waves, and are placed at a predetermined depth from the surface of the inspection table 1 in the recess 6 of the inspection table 1, facing the object to be measured 3. It is embedded so that Among the ultrasonic transducers 43 to 4n, at least one ultrasonic transducer 4c in the middle part is configured as a calibration ultrasonic transducer that compensates for changes in measured values due to temperature changes, and a calibration plate in the front 6 and a temperature sensor 7 in front of it. Reference numeral 8 denotes a detection sensor consisting of a limit switch or the like, which is attached to a corner of the surface of the inspection table 1 and detects that the object to be measured 3 is placed on the spacer 2 of the inspection table 1. 9 is an ultrasonic distance measuring device, which includes a plurality of ultrasonic transducers 4a and 4b.
, 4c, .
4b, 4c,...4n received.

Due to the propagation time of this transmitted and received wave, the ultrasonic transducers 4a and 4b
, 4c, . . . 4n and the distances from each part of the object to be measured 3 are measured. 10 is each ultrasonic transducer 4a, 4b, 4c, .
... 4n control unit, 11 is a delay unit that delays the output of the detection sensor 8 for a certain period of time, for example, about 10 seconds, and transmits a signal to the control unit 1o; 12 is the output of the ultrasonic distance measuring device 9 and the temperature sensor 7; This is an arithmetic processing unit that calibrates the temperature from the output of and converts it into the shape of the object to be measured 3.

Next, the operation of the above embodiment will be explained. The object to be measured 3 is placed on the spacer 2 of the inspection table 1. At this time, by making the shape of the surface of the inspection table 10 the same as the normal shape of the object to be measured 3 as described above, it is possible to determine whether or not there is an abnormality in the shape of the object to be measured 3. Then, the detection sensor 8 detects that the object to be measured 3 is placed on the inspection table 1. After this detection causes a delay of about 10 seconds in the delay unit 11, the control section 10 is operated. This causes the ultrasonic distance measuring device 9 to operate, and the ultrasonic transducers 4a, 4b, 4d, . At the same time, the ultrasonic transducer 4c transmits waves toward the calibration plates. The ultrasonic waves reflected on the surface of the object to be measured 3 are transmitted again to the ultrasonic transducers 4a, 4b,
4d, .
, 4d, . . . 40 and the distance to the object to be measured 3 is measured. As mentioned above, the ultrasonic transducers 4a, 4b, 4d, .
...Since 4n is installed at a predetermined depth from the surface of the inspection table 10, the distance between the surface of the inspection table 1 and the object to be measured 3 can be found by subtracting the predetermined depth from the previous measurement value. do. At this time, immediately after the object to be measured 3 is placed on the inspection table 1, when ultrasonic waves are transmitted from the ultrasonic transducers 4a, 4b, 4d,...4n, the object to be measured 3 is at a high temperature, so Ultrasonic output becomes extremely unstable due to fluctuations in the temperature and temperature rise. If the object to be measured 3 is made of glass with a temperature of up to 100°C and the thickness of the spacer 2 is increased to several degrees, the unstable period will be approximately 1
It will be 0 seconds. However, as mentioned above, delay unit 1
1 delays the transmission of ultrasonic waves for about 10 seconds, so
Ultrasonic waves can be output in a stable state.

On the other hand, even after 10 seconds have passed since the object to be measured 3 was placed on the inspection table 1, the object to be measured 3 and the ultrasonic transducers 4a, 4b, 4
A temperature gradient occurs between d, . . . 4n. This can be calibrated using the measured distance to the calibration plate 6 of the ultrasonic transducer 4c for calibrating temperature changes and the output of the temperature sensor 7. The distance measurement data obtained by each ultrasonic transducer is corrected by the arithmetic processing unit 12 together with the measurement value of the calibration ultrasonic transducer 4c and the output of the temperature sensor 7, and a shape representing the shape of the object to be measured 3 is obtained. is output and used to determine the presence or absence of an abnormality.

That is, the calibration ultrasonic transducer 4 at any temperature
ds the measured distance between C and the calibration plate 6, and the ultrasonic transducer 4a.
, 4b, 4d, . . . 4n and the measured distance between the object 3 and the measured object 3 is dm, then the distance d is given by the following equation.

d = dso + (dm - ds)

In the above embodiment, a limit switch is used as the detection sensor 8, but instead of such a contact type, an ultrasonic transducer 4a attached to the inspection table 1,
4b, 4d, -4n, to constantly transmit and receive ultrasonic waves, and constantly monitor whether or not there is a reflected wave within a predetermined reception time. It is possible to detect whether the test table 1 is placed on the examination table 1 or not. Further, the delay unit 11 may be incorporated into the control section 10 or the ultrasonic distance measuring device 9. Also, the ultrasonic transducer 4
By sequentially switching a, 4b, 4d, . . . 4n and repeating this several times, several measured values are obtained for one ultrasonic transducer, and from these measured values, Highly reliable measurement values that are less affected by fluctuations, that is, normally when fluctuations occur, the measured values become larger the farther away they are, so the minimum value among the measured values, or 2 to 3 data from the minimum value. The accuracy can be improved by using the average value of .

Effects of the Invention As described above, according to the present invention, the detection sensor detects that a high-temperature object is placed on the inspection table, and the delay unit starts the inspection after a predetermined period of time has elapsed until the atmosphere stabilizes. A plurality of ultrasonic transducers attached to the stand are driven, and the ultrasonic distance measuring device measures based on the ultrasonic propagation time, making it possible to measure in a stable state and improve the accuracy of shape measurement.

[Brief explanation of the drawing]

The figure is an explanatory diagram showing a shape inspection device in an embodiment of the present invention. 1... Inspection table, 3... Measured object, 4a, 4b, 4c
, 4d,... 4n... Ultrasonic transducer, 6... Calibration plate, 7... Temperature sensor, 8... Detection sensor, 9...
...Ultrasonic distance measuring device, 10...Control unit, 11...
- Delay unit, 12... Arithmetic processing section.

Claims (3)

[Claims] (1) An inspection table on which the object to be measured is installed at a predetermined position, a plurality of ultrasonic transducers attached to this inspection table, and a detection sensor that detects that the object to be measured is installed on the inspection table. and a delay unit for driving the ultrasonic transducer after a certain period of time has elapsed from the output of the detection sensor,
A shape inspection device comprising an ultrasonic distance measuring device connected to the ultrasonic transducer. (2) The shape inspection device according to claim 1, wherein at least one of the plurality of ultrasonic transducers is configured as an ultrasonic transducer for calibrating temperature changes. (3) A plurality of ultrasonic transducers are sequentially switched, the distance is measured multiple times, and a highly reliable measurement value is selected from the measured values. Shape inspection device as described in section.