Geometrical instruments – Gauge – Coordinate movable probe or machine
Patent
1998-07-14
2000-03-21
Fulton, Christopher W.
Geometrical instruments
Gauge
Coordinate movable probe or machine
33 1M, 33549, G01B 2108, G01B 506, G01B 706
Patent
active
060387793
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to an apparatus for measuring the thickness of various steel sheets and papers, and a method therefor. In particular, the present invention relates to an apparatus for measuring thicknesses and a method therefor, in which the flatness of thickness can also be measured.
DESCRIPTION OF THE PRIOR ART
There are many methods for measuring the thickness of various steel sheets and papers precisely to .mu.m (1/1000 mm) scale. That is, there are a method of using a micrometer, a method of using the usual measuring devices, a method of using a gage block comparator, and a method of using an on-line sheet thickness measuring apparatus.
The micrometer is used at a manufacturing site or in an inspection room. In this method, only the edge portion of a test piece can be measured, and the measurement is manually carried out. Therefore, much time is consumed in measuring the thickness, and the measurement reliability is low.
The method of using the usual thickness measuring device is utilized in automatized machine. That is, as shown in FIGS. 1(A) and (B), two sensors A and B are used upon and under the measuring points. That is, as shown in FIG. 1A, first the two distance sensors are adjusted to zero based on a reference thickness G. Then as shown in FIG. 1B, the sum addition of measuring displacements .DELTA.A and .DELTA.B plus the reference thickness G are calculated, thereby obtaining the thickness t (t=G+.DELTA.A+.DELTA.B).
In this method, however, the precision is low.
Meanwhile, the method of using the gage block comparator is based on the same principle as that of the usual thickness measuring device.
In this method however, only one point is manually measured, and therefore, the 3-dimensional contour such as the flatness of thickness for which the thickness data of the whole surface for the test piece are required cannot not be measured.
Meanwhile, the method of using the on-line sheet thickness measuring apparatus is described in Japanese Patent Laid-open No. Hei-4-116406. In this case also, the data on the test piece obtained from upper and lower distance sensors are utilized, the principle being almost same.
However, in this method, only one point can be measured, and further, the measuring precision cannot be made higher than several .mu.m.
In all the above described methods, only one point is measured. Therefore, if the average thickness of the entire surface of a test piece is to be measured, a special apparatus is required. Particularly, in the method of using a micrometer, the central area of a test piece cannot be measured.
Further, in some cases, not only the thickness but also the flatness of thickness have to be measured precisely. The flatness of thickness cannot be measured by measuring only one point, but the entire surface of the test piece has to be measured by applying a coordinate. Further, in this case, a large number of points has to be measured, and therefore, the measuring speed has to be very fast.
SUMMARY OF THE INVENTION
In order to solve the above described problems, the present inventor carried out much study, and as a result, the present inventor has come to propose the present invention.
Therefore it is an object of the present invention to provide an apparatus for measuring thickness and a method therefor, in which the precision is improved, the measuring time is shortened, the reliability is upgraded, and flatness of thickness also can be precisely measured.
In achieving the above object, the apparatus for measuring thickness according to the present invention includes:
a test piece retaining part consisting of: an X axis carrying part for retaining a test piece and being movable along X axis; a Y axis carrying part for retaining the X axis carrying part and being movable along Y axis; and a Z axis carrying part for retaining the X axis and Y axis carrying parts and being movable along Z axis; and
a test piece retaining part supporting table having a sensor retaining part for vertically movably retaining an upper sensor,
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Jung Seung Bae
Lee Eung Suk
Park June Ho
Park Wan Hee
Doan Quyen
Fulton Christopher W.
Pohang Iron & Steel Co. Ltd.
Research Institute of Industrial Science & Technology
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