CA1265925A - Continuous measurement of the surface roughness of a cold-rolled product - Google Patents
Continuous measurement of the surface roughness of a cold-rolled productInfo
- Publication number
- CA1265925A CA1265925A CA000524694A CA524694A CA1265925A CA 1265925 A CA1265925 A CA 1265925A CA 000524694 A CA000524694 A CA 000524694A CA 524694 A CA524694 A CA 524694A CA 1265925 A CA1265925 A CA 1265925A
- Authority
- CA
- Canada
- Prior art keywords
- product
- surface roughness
- cold
- light beam
- roughness
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/30—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces
Abstract
ABSTRACT
A light beam, e.g. from a laser, is transmitted onto the surface of a cold-rolled product such as steel strip.
The light beam has a wavelength at least equal to the maximum roughness of the product surface. The reflected light energy is measured, preferably in the specular direction with respect to the incident beam; the surface roughness is deduced from that measurement. The light beam may be interrupted to provide two beams alternately incident on the same spot at different angles.
A light beam, e.g. from a laser, is transmitted onto the surface of a cold-rolled product such as steel strip.
The light beam has a wavelength at least equal to the maximum roughness of the product surface. The reflected light energy is measured, preferably in the specular direction with respect to the incident beam; the surface roughness is deduced from that measurement. The light beam may be interrupted to provide two beams alternately incident on the same spot at different angles.
Description
~LZ65~
Continuous measurement of the surface roughness of a cold-rolled product BACKGROUND TO THE INVENTION
Field of Invention The invention relates to a continuous measurement process for the surface roughness of a cold-rolled product, more particularly cold-rolled strip Description of Prior Art ~ . . _ The roughness of cold-rolled strip has, of course, a considerable effect on its cold-working properties and its appearance after painting. Cold-rolled strip should therefore ; have a surface roughness which is as constant as possible throughout; also, strips to be used for the same purpose should all be of comparable roughness. It is therefnre important to monitor the roughness of strip produced in a cold-rolling mill to ensure very rapid detection of any deviation from permItted values.
Conventional monitoring takes the form of periodic ~sampling and laboratory testing of a strip sample. This method has the~disadvantage of being discontinuous and of requlrinq~rolllng to stop for the sample to be taken by cuttlng~the strlp. Also, this kind of examination cannot help to determine the~state of the entire strip. Furthermore, since the~sampIe l~S t~ak~en in the inoperative state, since the strip ,, , :.
1~ 5~
has to be stopped, it is not always representative of the rough-ness produced in the operative state.
of the possible methods of continuously determining the roughness of the surfac0 of a rolled product such as cold-rolled strip, only the optical method is at present used. In khe opti-cal method a beam of visible light is transmitked onto khs sur-face at a predetermined angle of incidence to the normal to the surface at the position of beam incidence, the beam reflected by the surfaces is collected, the reflected light energy is mea-sured, and a measurement o~ surface roughness is deduced.
we have found that when surface roughness is of a simi-lar order of magnitude to or greater than the wavelength of the light beam, the known method only provldes information on the slopes of the profile, i.e. of the peaks and troughs, but cannot provide an accurate measurement of the real height of the peaks and troughs.
Accordingly, the present invention provldes a method for continuously optically measuring the surface roughness of a cold-rolled product, comprising determining permitted surface roughness values for said product; transmitting an incident light beam having a wavelength at least egual to a maximum value of said permitted surface roughness values onto said product sur-face; receiving a light beam reflected from said product surface;
measuring the light intensity of said received reflected light beam; determining from said measured light intensity a measure value of surface roughness of the product; and comparing said measured value of surface roughness with said permitted surface roughness values.
The point is that there are various ways of determining the order of magnitude of the roughness of different cold-rolled products. For example, sheets which will subse~uently be used in the fabrication of tinplate usually have a roughness of less than
Continuous measurement of the surface roughness of a cold-rolled product BACKGROUND TO THE INVENTION
Field of Invention The invention relates to a continuous measurement process for the surface roughness of a cold-rolled product, more particularly cold-rolled strip Description of Prior Art ~ . . _ The roughness of cold-rolled strip has, of course, a considerable effect on its cold-working properties and its appearance after painting. Cold-rolled strip should therefore ; have a surface roughness which is as constant as possible throughout; also, strips to be used for the same purpose should all be of comparable roughness. It is therefnre important to monitor the roughness of strip produced in a cold-rolling mill to ensure very rapid detection of any deviation from permItted values.
Conventional monitoring takes the form of periodic ~sampling and laboratory testing of a strip sample. This method has the~disadvantage of being discontinuous and of requlrinq~rolllng to stop for the sample to be taken by cuttlng~the strlp. Also, this kind of examination cannot help to determine the~state of the entire strip. Furthermore, since the~sampIe l~S t~ak~en in the inoperative state, since the strip ,, , :.
1~ 5~
has to be stopped, it is not always representative of the rough-ness produced in the operative state.
of the possible methods of continuously determining the roughness of the surfac0 of a rolled product such as cold-rolled strip, only the optical method is at present used. In khe opti-cal method a beam of visible light is transmitked onto khs sur-face at a predetermined angle of incidence to the normal to the surface at the position of beam incidence, the beam reflected by the surfaces is collected, the reflected light energy is mea-sured, and a measurement o~ surface roughness is deduced.
we have found that when surface roughness is of a simi-lar order of magnitude to or greater than the wavelength of the light beam, the known method only provldes information on the slopes of the profile, i.e. of the peaks and troughs, but cannot provide an accurate measurement of the real height of the peaks and troughs.
Accordingly, the present invention provldes a method for continuously optically measuring the surface roughness of a cold-rolled product, comprising determining permitted surface roughness values for said product; transmitting an incident light beam having a wavelength at least egual to a maximum value of said permitted surface roughness values onto said product sur-face; receiving a light beam reflected from said product surface;
measuring the light intensity of said received reflected light beam; determining from said measured light intensity a measure value of surface roughness of the product; and comparing said measured value of surface roughness with said permitted surface roughness values.
The point is that there are various ways of determining the order of magnitude of the roughness of different cold-rolled products. For example, sheets which will subse~uently be used in the fabrication of tinplate usually have a roughness of less than
- 2 -~;
:: ;
'' :~Z65~
0.6~m whereas the roughness of strips ~or cold workiny usually varies between 1 and 3,~m.
In the case of cold-rolled strip for cold-working, a light beam whose wavelength is at least 5~ m is preferably used.
In one particular embodiment, a laser beam, preferably of a CO2 laser, is used.
A low-power laser beam of preferably less than 25 W may be used, in order not to damage the surface.
Advantageously, the incident laser beam is at an lncli-nation of approximately 50 to the normal to the surface.
1~
In a useful embodiment of the process according to the invention, the roughness of a moving strip is measured continu-ously by means of a light beam transmitter and receiver disposed on the path of the strip.
It has been found very advantageous in this connection to continuously measure the roughness of a strip at its exlt from the skin-pass mill by means of a measuring system -, :
~ ~ -: '; .. '' :
:.
, ~2~S~5 comprising a C02 laser of a power of 4 W and a pyro-electric cell collecting the laser beam specularly reflected by the strip surface. rhe tneasuring systern was disposed immediately at the mill exit so that the incident an~
reflected beams defined a vertical plane perpendicular to the direction of strip movement. The angle of incidence was approximately 50.
In another very interesting embodiment of the process according to the invention, a light beam of a wavelength at least equal to the maximum roughness of the product surface is transmitted on to the said surface, the beam is periodically interrupted; during the uninterrupted part of the transmission the light beam is transmitted directly on to the product surface at a first angle of incidence ~1' during the interrupted part of the period the beam is deflected and i5 transmitted indirectly to the product surface at a second angle of incidence ~2' the reflected beams corresponding to the direct and indirect incident beams are ~collected, the light energy oF the reflected beams is 20 ~measured, and a measurement of surface roughness is deduced.
In this procedure the use of the measurements of the light energy reflected at two different angles helps to redu e the effect of power fluctuations of the beam-emitting source and of varying absorptions of the light radiation by the product : :
~ 25 surface.
- :
: - . : :: - ~ : ~
, : - ,~ ~
, ~ . ~ : , ~:
~Z~5~5 The invention will be described further, by way of example, with reference to the accorr1panying drawings~
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 illustrates the light reflection associated with a wavelength, ~ , less than the surface roughness, Ra;
Fig. 2 illustrates the diffraction of the light when the wavelength, ~ , is greater than the surface roughness, Ra;
Fig. 3 is a diagrammatic view of a device For a very interesting embodiment using partial deflection of the incident beam; and Fig. 4 shows the correlation between the roughness results obtained by optical measurement according to the invention and the results obtained by a conventional mechanical measurement.
Flg. 1 illustrates the reflection of light by a surface when the light wavelength, ~ , is near to or less than the surface roughness, Ra. The surface can be considered as conslstlng of a large number of small mirrors of random shaoe, size, and orientation. Consequently, measurement of the reFlected radiation gives 1nformation about the slope of the roughness~profile but not on the amplitude thereof and 50 does not provi~de any measurement of roughness.
~ ' ::
, .. ~ : : -- ~
~Z~59'~5 Fig. 2 Fig. 2 shows how light i5 ~iffracted by a surface when the light wavelength, ~ , is greater than the surface roughness, Ra. The point is that in this case the surface roughness behaves like a random diffraction network leading to an angular distribution of the reflected light intensity. The angular distribution depends upon the amplitude of the roughness and this dependence can be determined experimentally , : ::
, .
, : , :
: ~ :
- ~
~: : : ~ : : ::
~ ~ , ~5~5 by appropriate calibration of the device usecl to measure the reflected light :intensity.
Fiq. 3 diagrammatically illustrates a device for a particularly interesting embodiment of the process according to the invention. It is re~uired to measure the roughness of a steel strip 1. A
C2 laser source 2 emit~ a continuous laser beam
:: ;
'' :~Z65~
0.6~m whereas the roughness of strips ~or cold workiny usually varies between 1 and 3,~m.
In the case of cold-rolled strip for cold-working, a light beam whose wavelength is at least 5~ m is preferably used.
In one particular embodiment, a laser beam, preferably of a CO2 laser, is used.
A low-power laser beam of preferably less than 25 W may be used, in order not to damage the surface.
Advantageously, the incident laser beam is at an lncli-nation of approximately 50 to the normal to the surface.
1~
In a useful embodiment of the process according to the invention, the roughness of a moving strip is measured continu-ously by means of a light beam transmitter and receiver disposed on the path of the strip.
It has been found very advantageous in this connection to continuously measure the roughness of a strip at its exlt from the skin-pass mill by means of a measuring system -, :
~ ~ -: '; .. '' :
:.
, ~2~S~5 comprising a C02 laser of a power of 4 W and a pyro-electric cell collecting the laser beam specularly reflected by the strip surface. rhe tneasuring systern was disposed immediately at the mill exit so that the incident an~
reflected beams defined a vertical plane perpendicular to the direction of strip movement. The angle of incidence was approximately 50.
In another very interesting embodiment of the process according to the invention, a light beam of a wavelength at least equal to the maximum roughness of the product surface is transmitted on to the said surface, the beam is periodically interrupted; during the uninterrupted part of the transmission the light beam is transmitted directly on to the product surface at a first angle of incidence ~1' during the interrupted part of the period the beam is deflected and i5 transmitted indirectly to the product surface at a second angle of incidence ~2' the reflected beams corresponding to the direct and indirect incident beams are ~collected, the light energy oF the reflected beams is 20 ~measured, and a measurement of surface roughness is deduced.
In this procedure the use of the measurements of the light energy reflected at two different angles helps to redu e the effect of power fluctuations of the beam-emitting source and of varying absorptions of the light radiation by the product : :
~ 25 surface.
- :
: - . : :: - ~ : ~
, : - ,~ ~
, ~ . ~ : , ~:
~Z~5~5 The invention will be described further, by way of example, with reference to the accorr1panying drawings~
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 illustrates the light reflection associated with a wavelength, ~ , less than the surface roughness, Ra;
Fig. 2 illustrates the diffraction of the light when the wavelength, ~ , is greater than the surface roughness, Ra;
Fig. 3 is a diagrammatic view of a device For a very interesting embodiment using partial deflection of the incident beam; and Fig. 4 shows the correlation between the roughness results obtained by optical measurement according to the invention and the results obtained by a conventional mechanical measurement.
Flg. 1 illustrates the reflection of light by a surface when the light wavelength, ~ , is near to or less than the surface roughness, Ra. The surface can be considered as conslstlng of a large number of small mirrors of random shaoe, size, and orientation. Consequently, measurement of the reFlected radiation gives 1nformation about the slope of the roughness~profile but not on the amplitude thereof and 50 does not provi~de any measurement of roughness.
~ ' ::
, .. ~ : : -- ~
~Z~59'~5 Fig. 2 Fig. 2 shows how light i5 ~iffracted by a surface when the light wavelength, ~ , is greater than the surface roughness, Ra. The point is that in this case the surface roughness behaves like a random diffraction network leading to an angular distribution of the reflected light intensity. The angular distribution depends upon the amplitude of the roughness and this dependence can be determined experimentally , : ::
, .
, : , :
: ~ :
- ~
~: : : ~ : : ::
~ ~ , ~5~5 by appropriate calibration of the device usecl to measure the reflected light :intensity.
Fiq. 3 diagrammatically illustrates a device for a particularly interesting embodiment of the process according to the invention. It is re~uired to measure the roughness of a steel strip 1. A
C2 laser source 2 emit~ a continuous laser beam
3 towards the strip 1. The beam 3 is periodically interrupted by a perforated disc 4 rotating at a high speed. The disc is pierced with a number of windows separated by opaque zones, the windows and the opaaue zones being disposed in consecutive and alternate relationship in a ring near the disc outer edge~ When the disc 4 rotates the beam 1 lS is alternately transmitted through a window, then interrupted by an opaque zone. The directly transmitted beam S strikes the strip surface at a position P
at a first angle of incidence ~ 1 and the correspon-ding reflected ~beam 6 is received by a first pyro- r ~ electric cell 7~which measures its intensity Il.
The opaque zones of the disc 4 are reflectin~ surfaces so that the beam when interrupted by any opaque zone is deflected to a mirror 8 which reflects it as~;a~beam ~ to the surface position P at a second angle of incidence ~ 2. The correspondin~
, : ~: :
;
reflected beam 10 is received by a second pyroelectric cell ll~which measures its intensity I~. Preferahly, the two pyroelectric cells are disposed in the direction of specular reflection of the respective incident beams; to this end, their position can be controlled by variations in strip inclination.
The measurement of surface roughness of the strip is based on the following principle:
The light intensity I reflected specularly 10 at an angle ~ to the normal to the surface is given by the formula: :
I = Io. exp (-K. cos 2 C< . Ra 2 ) ( 1 ) in which I denotes the intensity reflected by a o zero-roughness completely smooth surface, Ra denotes surface roughness, and K denotes a constant which depends upon the measurement units.
The intensity lo can be affected by fluctuations of different factors such as the power of the light 0 - source, the extent of radiation absorption by the surface,~nd the angle of incidence or sensitivity of the cell. To allow for these factors the value I is considered to consist of an average stable o : ~ component. 1~ and a variable component ~ which 25 :~ is usually small.
:
~: : : :
~ ; ~
~ - ~ . , " ;: ..
5~S
. Therefore:
o m .
In the present case formula (1) applied to the two directly and indirectly transmitted beams can be stated for the respective beams as follows:
m~ exp (~ K. cos2 ~ 2~ (2) I2 - (Im2 ~ ~ 2) ~ exp (- K. co~2 d2 ~ Ra2) (3) To minimize measurement fluctuations:
( ~ 2 + (~2 )2 Iml lm~ must be very small. (4) In these formulæ Il and I2 denote the measured IS lntensities,whereas Iml and Im2 are determined for a given system by a few calibration tests.
Formulae (2), (3)~ and (4) are therefore a mean.s of determlning the arithmetical mean rouqhness Ra of the strip surface.
Exa ple The system hereinbefore described was used to measure the roughness of cold-rolled qteel strips.
In~a previous mechanical measurement with an 8 ~m : :
25~ cut-off - i.e., hy eliminating surface profile vari,~t~)ns :
of a wavelength greater than 8 mm - the strips had a roughness between 0.8 and 4 micromete~s. 30 samples were tested in the folLowing conditions:
Power of C02 laser: 6 W
Distance between the laser and the place of impact: 570 mm Distance between the place of impact and the cells: 570 mm Angle of incidence b~ 1 = 65 Angle of incidence ~ 2 = 50 Linear speed of strip: 65 m/min.
Fig. 4 collates the results and shows the correlation between the result of the optical measurements in accordance with the invention ~Ra opt) along the ordinate and the result of conventional mechanical measurements (Ra mec) along the abscissa, the measurements being made with an 8 mm cut-off as previously explained. The correlation is clearly excellent, the maximum deviation being + 10~, which is quite adequate in view of the inaccuracy of the mechanical measurement.
The invention is not of course limited lust to the embodiments hereinbefore described and illustrated.
~ More partlcularly, the invention woul~ cover A :
~: .
`'~ : " ' ~' '" ' :
..: -s the use of two separate light beams instead of a single beam broken up as hereinbefore describecl.
This feature would not necessarily be advantageous for it would call for the use of clual equipment and might inter alia cause serious interference problems.
Also, an appropriate device could be provided to reduce the divergence of the light beam, more particularly of the laser beam, when there is a long distance between the transmitter and the surface.
Nor is the invention linked with any particular orientation of the vertical plane formed by the incident and reflected beams relatively to the direction of movement of the surface.
Also, and still in accordance with the invention, the roughness can be measured continuously and simul-taneously at a number of points distributed over product width by means of a number of measurement systems corresponding to these various aiming points.
20 ~ This procedure helps to determine the distribution of roughness over the width of the rolled product, for example, oE a cold-rolled strip.
The process according to the invention helps to monitor the longitudinal roughness trend of a ~ ~ cold-rolled strip and to immediately detect the ; ` .
i59Z5 time when the roll needs changing. The process according to the invention helps to obviate long downtimes of the rolling mill and product losses, :
: :
' :
at a first angle of incidence ~ 1 and the correspon-ding reflected ~beam 6 is received by a first pyro- r ~ electric cell 7~which measures its intensity Il.
The opaque zones of the disc 4 are reflectin~ surfaces so that the beam when interrupted by any opaque zone is deflected to a mirror 8 which reflects it as~;a~beam ~ to the surface position P at a second angle of incidence ~ 2. The correspondin~
, : ~: :
;
reflected beam 10 is received by a second pyroelectric cell ll~which measures its intensity I~. Preferahly, the two pyroelectric cells are disposed in the direction of specular reflection of the respective incident beams; to this end, their position can be controlled by variations in strip inclination.
The measurement of surface roughness of the strip is based on the following principle:
The light intensity I reflected specularly 10 at an angle ~ to the normal to the surface is given by the formula: :
I = Io. exp (-K. cos 2 C< . Ra 2 ) ( 1 ) in which I denotes the intensity reflected by a o zero-roughness completely smooth surface, Ra denotes surface roughness, and K denotes a constant which depends upon the measurement units.
The intensity lo can be affected by fluctuations of different factors such as the power of the light 0 - source, the extent of radiation absorption by the surface,~nd the angle of incidence or sensitivity of the cell. To allow for these factors the value I is considered to consist of an average stable o : ~ component. 1~ and a variable component ~ which 25 :~ is usually small.
:
~: : : :
~ ; ~
~ - ~ . , " ;: ..
5~S
. Therefore:
o m .
In the present case formula (1) applied to the two directly and indirectly transmitted beams can be stated for the respective beams as follows:
m~ exp (~ K. cos2 ~ 2~ (2) I2 - (Im2 ~ ~ 2) ~ exp (- K. co~2 d2 ~ Ra2) (3) To minimize measurement fluctuations:
( ~ 2 + (~2 )2 Iml lm~ must be very small. (4) In these formulæ Il and I2 denote the measured IS lntensities,whereas Iml and Im2 are determined for a given system by a few calibration tests.
Formulae (2), (3)~ and (4) are therefore a mean.s of determlning the arithmetical mean rouqhness Ra of the strip surface.
Exa ple The system hereinbefore described was used to measure the roughness of cold-rolled qteel strips.
In~a previous mechanical measurement with an 8 ~m : :
25~ cut-off - i.e., hy eliminating surface profile vari,~t~)ns :
of a wavelength greater than 8 mm - the strips had a roughness between 0.8 and 4 micromete~s. 30 samples were tested in the folLowing conditions:
Power of C02 laser: 6 W
Distance between the laser and the place of impact: 570 mm Distance between the place of impact and the cells: 570 mm Angle of incidence b~ 1 = 65 Angle of incidence ~ 2 = 50 Linear speed of strip: 65 m/min.
Fig. 4 collates the results and shows the correlation between the result of the optical measurements in accordance with the invention ~Ra opt) along the ordinate and the result of conventional mechanical measurements (Ra mec) along the abscissa, the measurements being made with an 8 mm cut-off as previously explained. The correlation is clearly excellent, the maximum deviation being + 10~, which is quite adequate in view of the inaccuracy of the mechanical measurement.
The invention is not of course limited lust to the embodiments hereinbefore described and illustrated.
~ More partlcularly, the invention woul~ cover A :
~: .
`'~ : " ' ~' '" ' :
..: -s the use of two separate light beams instead of a single beam broken up as hereinbefore describecl.
This feature would not necessarily be advantageous for it would call for the use of clual equipment and might inter alia cause serious interference problems.
Also, an appropriate device could be provided to reduce the divergence of the light beam, more particularly of the laser beam, when there is a long distance between the transmitter and the surface.
Nor is the invention linked with any particular orientation of the vertical plane formed by the incident and reflected beams relatively to the direction of movement of the surface.
Also, and still in accordance with the invention, the roughness can be measured continuously and simul-taneously at a number of points distributed over product width by means of a number of measurement systems corresponding to these various aiming points.
20 ~ This procedure helps to determine the distribution of roughness over the width of the rolled product, for example, oE a cold-rolled strip.
The process according to the invention helps to monitor the longitudinal roughness trend of a ~ ~ cold-rolled strip and to immediately detect the ; ` .
i59Z5 time when the roll needs changing. The process according to the invention helps to obviate long downtimes of the rolling mill and product losses, :
: :
' :
Claims (12)
1. A method for continuously optically measuring the surface roughness of a cold-rolled product, comprising:
determining permitted surface roughness values for said product;
transmittingan incident light beam having a wavelength at least equal to a maximum value of said permitted surface roughness values onto said product surface;
receiving a light beam reflected from said product surface;
measuring the light intensity of said received reflected light beam;
determining from said measured light intensity a measured value of surface roughness of the product; and comparing said measured value of surface roughness with said permitted surface roughness values.
determining permitted surface roughness values for said product;
transmittingan incident light beam having a wavelength at least equal to a maximum value of said permitted surface roughness values onto said product surface;
receiving a light beam reflected from said product surface;
measuring the light intensity of said received reflected light beam;
determining from said measured light intensity a measured value of surface roughness of the product; and comparing said measured value of surface roughness with said permitted surface roughness values.
2. The process of claim 1, further comprising the steps of interrupting the incident lightbeam periodically;
transmitting the uninterrupted part of the incident light beam directly onto the product surface at a first angle of incidence .alpha.1; deflecting the interrupted part of the beam and transmitting it indirectly to the same position of the product surface at a second angle of incidence .alpha.2;collecting reflected beams corresponding to the direct and indirect incident beams;
measuring the light energy of the reflected beams; and deducing therefrom a measurement of surface roughness.
transmitting the uninterrupted part of the incident light beam directly onto the product surface at a first angle of incidence .alpha.1; deflecting the interrupted part of the beam and transmitting it indirectly to the same position of the product surface at a second angle of incidence .alpha.2;collecting reflected beams corresponding to the direct and indirect incident beams;
measuring the light energy of the reflected beams; and deducing therefrom a measurement of surface roughness.
3. The process of claim 1, in which the said product is cold-rolled strip for cold working and the wavelength of the light beam is at least 5 µm.
4. The process of claim 1, in which the light beam is a laser beam.
5. The process of claim 4, in which the laser beam is product by a CO2 laser.
6. The process of claim 4, in which the laser beam has a power of less than 25 W.
7. The process of claim 1. in which the incident beam is at an inclination of approximately 50° to the normal to the product surface.
8. The process of claim 1, in which the light energy reflected in the specular direction is collected.
9. The process of claim 1, in which the roughness is measured at a number of places over the width of the product.
10. The method of claim 1, wherein said permitted values of surface roughness are in the range of 1 to 3 µm for cold-rolled strip products for deep drawing and less than 0.6 µm for cold-rolled black plates for tin plate fabrication.
11. The method of claim 1, wherein said permitted surface roughness values are determined mechanically.
12. The method of claim 1, further comprising:
monitoring the trend of the measured surface roughness along a longitudinal direction of a cold-rolled strip product;
detecting when a deviation resulting from said comparison of said measured and permitted roughness values exceeds a predetermined value; and determining from said detected deviation when a roll of said product needs to be changed.
monitoring the trend of the measured surface roughness along a longitudinal direction of a cold-rolled strip product;
detecting when a deviation resulting from said comparison of said measured and permitted roughness values exceeds a predetermined value; and determining from said detected deviation when a roll of said product needs to be changed.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| LU86194A LU86194A1 (en) | 1985-12-05 | 1985-12-05 | METHOD FOR THE CONTINUOUS MEASUREMENT OF THE ROUGHNESS OF THE SURFACE OF A COLD ROLLED PRODUCT |
| LU86,194 | 1985-12-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1265925A true CA1265925A (en) | 1990-02-20 |
Family
ID=19730594
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000524694A Expired CA1265925A (en) | 1985-12-05 | 1986-12-05 | Continuous measurement of the surface roughness of a cold-rolled product |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4803374A (en) |
| EP (1) | EP0229603B1 (en) |
| JP (1) | JPS62148842A (en) |
| BE (1) | BE905862A (en) |
| CA (1) | CA1265925A (en) |
| DE (1) | DE3670152D1 (en) |
| ES (1) | ES2014998B3 (en) |
| LU (1) | LU86194A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3737632A1 (en) * | 1987-11-05 | 1989-05-24 | Sick Optik Elektronik Erwin | OPTICAL SURFACE RULING MEASURING DEVICE |
| JP2918045B2 (en) * | 1988-10-28 | 1999-07-12 | 株式会社リコー | Image density control device |
| JPH0339605A (en) * | 1989-07-05 | 1991-02-20 | Brother Ind Ltd | Optical surface shape measuring instrument |
| US5142648A (en) * | 1990-08-02 | 1992-08-25 | General Motors Corporation | Method and apparatus for paint inspection |
| DE4114671A1 (en) * | 1991-05-06 | 1992-11-12 | Hoechst Ag | METHOD AND MEASURING ARRANGEMENT FOR CONTACTLESS ON-LINE MEASUREMENT |
| FI935180A0 (en) * | 1993-11-22 | 1993-11-22 | Rautaruukki Oy | Construction of calibrating devices, calibration devices |
| US5608527A (en) * | 1995-03-08 | 1997-03-04 | Optical Dimensions, Llc | Apparatus and method for dynamic measurement of surface roughness |
| US5781302A (en) * | 1996-07-22 | 1998-07-14 | Geneva Steel | Non-contact shape meter for flatness measurements |
| US6233053B1 (en) * | 1997-07-29 | 2001-05-15 | Honeywell International Inc | Dual standard gloss sensor |
| IT1302609B1 (en) | 1998-10-06 | 2000-09-29 | Techint Spa | PROCEDURE AND RELATED EQUIPMENT FOR MEASURING THE DEVIATION OF SHAPE OF WORKED SURFACES. |
| FR2784018B1 (en) * | 1998-10-06 | 2000-12-08 | Serobiologiques Lab Sa | METHOD FOR MEASURING THE REFLECTION PROPERTIES OF A SURFACE AND DEVICE FOR IMPLEMENTING SAME |
| US6247238B1 (en) | 1999-04-15 | 2001-06-19 | Greg Harvey | Laser marking device |
| JP3525432B2 (en) * | 2000-09-29 | 2004-05-10 | 株式会社東京精密 | Roughness measuring method and roughness measuring device |
| JP3632153B2 (en) * | 2000-11-06 | 2005-03-23 | 株式会社東京精密 | Roughness measuring method and roughness measuring apparatus |
| KR20030053077A (en) * | 2001-12-22 | 2003-06-28 | 재단법인 포항산업과학연구원 | Measurement of the surface roughness of a steel palte roiied by EDT roll |
| BE1015227A3 (en) | 2002-11-29 | 2004-11-09 | Centre Rech Metallurgique | Method and apparatus for determining line of surveying micrometric products in motion. |
| JP2006266728A (en) * | 2005-03-22 | 2006-10-05 | Honda Motor Co Ltd | Evaluation method of paint film appearance, and painted article |
| DE102007050557B4 (en) * | 2007-10-20 | 2013-01-24 | Hochschule Mittweida (Fh) | Device for rapid integral and non-contact measurement of roughness |
| JP5551001B2 (en) * | 2010-06-22 | 2014-07-16 | 株式会社Ｐｆｕ | Friction coefficient estimation device and friction coefficient estimation method |
| US8582117B2 (en) | 2011-04-08 | 2013-11-12 | Schmitt Industries, Inc. | Systems and methods for calibrating an optical non-contact surface roughness measurement device |
| CN114894800B (en) * | 2022-07-13 | 2022-09-16 | 西南石油大学 | Petroleum casing mark detection device and method based on computer vision |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| LU56223A1 (en) * | 1968-06-07 | 1970-01-14 | ||
| US4548506A (en) * | 1979-12-26 | 1985-10-22 | The United States Of America As Represented By The Secretary Of The Navy | Nondestructive analysis of multilayer roughness correlation |
| LU82230A1 (en) * | 1980-03-07 | 1981-10-30 | Centre Rech Metallurgique | SURFACE QUALITY CONTROL PROCESS |
| DE3173451D1 (en) * | 1981-09-17 | 1986-02-20 | Ibm Deutschland | Method for interferometric surface topography |
| BE893365A (en) * | 1982-05-28 | 1982-09-16 | Centre Rech Metallurgique | Metal surface quality control by laser - using reflectivity as an indication of roughness |
| FR2531776A1 (en) * | 1982-08-13 | 1984-02-17 | Commissariat Energie Atomique | METHOD AND DEVICE FOR NON-CONTACT DETERMINATION OF ROUGHNESS OF SURFACE |
| US4650330A (en) * | 1983-05-13 | 1987-03-17 | Citizen Watch Co., Ltd. | Surface condition measurement apparatus |
| CA1216169A (en) * | 1983-05-23 | 1987-01-06 | Joseph A. Freilino | Method of determining surface roughness using a visible and infrared laser source |
| JPS602601A (en) * | 1983-06-20 | 1985-01-08 | Hitachi Ltd | Method for releasing sintered article from sleeve for hot press |
| US4629319A (en) * | 1984-02-14 | 1986-12-16 | Diffracto Ltd. | Panel surface flaw inspection |
-
1985
- 1985-12-05 LU LU86194A patent/LU86194A1/en unknown
-
1986
- 1986-12-03 DE DE8686870181T patent/DE3670152D1/en not_active Expired - Lifetime
- 1986-12-03 ES ES86870181T patent/ES2014998B3/en not_active Expired - Lifetime
- 1986-12-03 EP EP86870181A patent/EP0229603B1/en not_active Expired - Lifetime
- 1986-12-03 BE BE6/48271A patent/BE905862A/en not_active IP Right Cessation
- 1986-12-04 JP JP61289723A patent/JPS62148842A/en active Pending
- 1986-12-05 US US06/938,239 patent/US4803374A/en not_active Expired - Fee Related
- 1986-12-05 CA CA000524694A patent/CA1265925A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| ES2014998B3 (en) | 1990-08-01 |
| JPS62148842A (en) | 1987-07-02 |
| US4803374A (en) | 1989-02-07 |
| EP0229603B1 (en) | 1990-04-04 |
| EP0229603A1 (en) | 1987-07-22 |
| DE3670152D1 (en) | 1990-05-10 |
| BE905862A (en) | 1987-06-03 |
| LU86194A1 (en) | 1987-07-24 |
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