CA2353600A1 - Automatic check of the hydrophilicity of a solid surface using infrared spectroscopy - Google Patents
Automatic check of the hydrophilicity of a solid surface using infrared spectroscopy Download PDFInfo
- Publication number
- CA2353600A1 CA2353600A1 CA002353600A CA2353600A CA2353600A1 CA 2353600 A1 CA2353600 A1 CA 2353600A1 CA 002353600 A CA002353600 A CA 002353600A CA 2353600 A CA2353600 A CA 2353600A CA 2353600 A1 CA2353600 A1 CA 2353600A1
- Authority
- CA
- Canada
- Prior art keywords
- infrared radiation
- intensity
- radiation reflected
- water
- specified
- 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.)
- Abandoned
Links
- 239000007787 solid Substances 0.000 title claims abstract description 6
- 238000004566 IR spectroscopy Methods 0.000 title description 2
- 238000000034 method Methods 0.000 claims abstract description 66
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 57
- 229920003023 plastic Polymers 0.000 claims abstract description 6
- 239000004033 plastic Substances 0.000 claims abstract description 6
- 230000005855 radiation Effects 0.000 claims description 68
- 238000004140 cleaning Methods 0.000 claims description 48
- 238000005259 measurement Methods 0.000 claims description 27
- 238000000576 coating method Methods 0.000 claims description 11
- 239000011248 coating agent Substances 0.000 claims description 10
- 238000006243 chemical reaction Methods 0.000 claims description 9
- 238000009736 wetting Methods 0.000 claims description 9
- 239000000126 substance Substances 0.000 claims description 7
- 239000000203 mixture Substances 0.000 claims description 5
- 238000012545 processing Methods 0.000 claims description 4
- 238000012552 review Methods 0.000 claims description 2
- 230000000694 effects Effects 0.000 abstract description 3
- 238000012544 monitoring process Methods 0.000 abstract 1
- 238000000746 purification Methods 0.000 abstract 1
- 238000012360 testing method Methods 0.000 description 20
- 239000003981 vehicle Substances 0.000 description 20
- 229910052751 metal Inorganic materials 0.000 description 16
- 239000002184 metal Substances 0.000 description 16
- 238000010521 absorption reaction Methods 0.000 description 14
- 239000003921 oil Substances 0.000 description 10
- 238000004519 manufacturing process Methods 0.000 description 6
- 238000004458 analytical method Methods 0.000 description 5
- 238000009776 industrial production Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000010276 construction Methods 0.000 description 4
- 238000000275 quality assurance Methods 0.000 description 4
- 238000004381 surface treatment Methods 0.000 description 4
- 239000000356 contaminant Substances 0.000 description 3
- 230000002209 hydrophobic effect Effects 0.000 description 3
- 230000000717 retained effect Effects 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- 230000000007 visual effect Effects 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 238000000641 cold extrusion Methods 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 238000003754 machining Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 229910001335 Galvanized steel Inorganic materials 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 230000003044 adaptive effect Effects 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 238000007743 anodising Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000004532 chromating Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 239000010960 cold rolled steel Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000005670 electromagnetic radiation Effects 0.000 description 1
- 239000003925 fat Substances 0.000 description 1
- 150000002222 fluorine compounds Chemical class 0.000 description 1
- 239000008397 galvanized steel Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 230000005661 hydrophobic surface Effects 0.000 description 1
- 230000005865 ionizing radiation Effects 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 229940056932 lead sulfide Drugs 0.000 description 1
- 229910052981 lead sulfide Inorganic materials 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 238000009740 moulding (composite fabrication) Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229920000620 organic polymer Polymers 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 229910001428 transition metal ion Inorganic materials 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- -1 tungsten halogen Chemical class 0.000 description 1
- 239000004924 water-based lacquer Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J3/42—Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry
- G01J3/433—Modulation spectrometry; Derivative spectrometry
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3563—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing solids; Preparation of samples therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0002—Organic membrane manufacture
- B01D67/0023—Organic membrane manufacture by inducing porosity into non porous precursor membranes
- B01D67/0032—Organic membrane manufacture by inducing porosity into non porous precursor membranes by elimination of segments of the precursor, e.g. nucleation-track membranes, lithography or laser methods
- B01D67/0034—Organic membrane manufacture by inducing porosity into non porous precursor membranes by elimination of segments of the precursor, e.g. nucleation-track membranes, lithography or laser methods by micromachining techniques, e.g. using masking and etching steps, photolithography
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/10—Arrangements of light sources specially adapted for spectrometry or colorimetry
- G01J3/108—Arrangements of light sources specially adapted for spectrometry or colorimetry for measurement in the infrared range
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3577—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing liquids, e.g. polluted water
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J3/42—Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry
- G01J3/433—Modulation spectrometry; Derivative spectrometry
- G01J2003/4332—Modulation spectrometry; Derivative spectrometry frequency-modulated
Landscapes
- Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- General Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Pathology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Health & Medical Sciences (AREA)
- Immunology (AREA)
- Analytical Chemistry (AREA)
- Optics & Photonics (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Manufacturing & Machinery (AREA)
- Engineering & Computer Science (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
- Cleaning By Liquid Or Steam (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Abstract
The invention relates to a method for controlling the hydrophilicity of a solid surface after a hydrophilizing treatment. According to said method, the surface is wetted with water, irradiated with infrared light, the intensity of the infrared light reflected by the surface is measured at a predetermined wavelength or at several predetermined wavelengths and the intensity measured is used to determine the median occupation with water of the surface. The method can be used, for example, for automatically controlling the effect of a purification process or a hydrophilizing treatment of plastics. If the results detected are insufficient, preferably alarm messages are output and/or measures for monitoring the preceding process steps are initiated.
Description
"Automatic check of the hydrophilicity of a solid surface using infrared spectroscopy"
s This invention describes a process, which preferably proceeds automatically, for determining the hydrophilicity of a surface in one or more places. The wettability of a surface with water may be determined in one or more places by this means. For example, the success of a to hydrophilizing treatment of plastics surfaces, prior to the lacquering thereof with water-based lacquers, for example, may be checked by such means. In particular, the process is suitable for checking the outcome of a cleaning of the solid surface, wherein hydrophobic surface i5 contaminants, such as fats or oils, are removed. The more hydrophilic the surface has been rendered by cleaning, i . a . the greater the average coverage of the surface with water after cleaning, the more completely have the hydrophobic contaminants been removed from the surface.
zo By this means, it is possible, for example, to check the success of a cleaning of objects made of metal, plastic, glass and/or ceramics, for example in the course of the manufacture or machining of such components. Furthermore, the present invention is also suitable, for example, for 2s verifying the success of the cleaning of crockery and/or trays in continuous cleaning units.
The present invention relates in particular to the field of cleaning hard surfaces in industrial production 3o processes. The present invention is applicable in particular to metal surfaces which are covered with anti-corrosive oils or with oils which facilitate shaping processes, such as rolling, forming, drawing, cold extrusion or machining. The present invention relates to 35 that part of an industrial production line in which this oil should be at least substantially removed from the surfaces by cleaning in order subsequently to subject the surfaces to a further treatment, such as a chemical conversion (conversion treatment) or a coating, for example. The conversion treatment may, for example, be phosphating, with or without film-forming, chromating, anodizing or a treatment using solutions which contain s transition metal ions and/or single-bonded and/or complexed fluorides and/or the acids thereof. An example of coating is coating using organic polymers or using those organic substances which crosslink and form polymers when heated and/or when irradiated with infrared, visible to or ultraviolet radiation (such as lacquering) or coating using metal coatings, such as coating with metallic zinc, nickel, chromium, aluminum or with alloys, at least 50% of which consist of the said elements in each case.
15 There is a multiplicity of industrial production processes in which metal strip or moulded parts made of metal are formed and/or joined and then cleaned in order to prepare the surface for further treatment steps, such as conversion treatment or coating. For the forming 2o processes, the surfaces are generally covered with rolling or forming oils which are to facilitate forming and, in particular, prevent bonding of the metal surface of the workpiece with the tool. Examples of such forming processes are non-cutting processes such as rolling, 2s bending, drawing or cold extrusion and processes which are not chipless, such as cutting, drilling or milling. If metallic materials are stored and/or transported between different processing stages it is conventional to protect the surfaces from corrosion by means of an anti-corrosive 30 oil. Before the further treatment steps of chemical conversion treatment and/or coating which have been exemplified above, these oils must be removed by means of suitable cleaner solutions at least so extensively that residual quantities of oil left behind on the surfaces do 35 not have a negative impact on the subsequent process steps. Successful cleaning is evident from the fact that, after cleaning, the surface is so hydrophilic that the water film on the surface after cleaning does not break up within a time interval to be specified, between 10 seconds and 2 minutes, for example, and the water does not run off more or less completely. A surface which has been s successfully cleaned using an aqueous cleaner solution is thus coated with an even water film after cleaning.
Traditionally a so-called "water break test" is carried out to check the hydrophilicity of the cleaned surface.
io This involves a visual assessment of the percentage of the surface which is not or is no longer wetted with water immediately after wetting or within up to about 2 minutes of wetting. The greater the percentage of non-wetted partial areas of the surface, the poorer the result of 15 cleaning. Although a visual assessment of this type is simple to carry out, staff need to be available to perform it. In the past, this test has conventionally been carried out on sample parts in the laboratory and not on the original workpieces in the production line.
It is known to determine the water content of solvents or the moisture content of products by determining the absorption by the sample of infrared radiation at one or more specified wavelengths. The specified wavelengths are 2s selected in such a way that water absorbs the infrared radiation particularly intensely at these wavelengths. As is known, by infrared radiation is meant that portion of the spectrum of electromagnetic radiation which adjoins the longwave limit of the sensitivity of the human eye at 3o about 760 nm. At wavelengths in the region of about 1 mm, infrared radiation becomes microwave radiation. In the narrower sense, the wavelength range between about 760 and about 15000 nm may be termed infrared radiation.
Wavelengths in the range of the so-called near infrared 35 radiation in particular are suitable for the quantitative determination of water. This may be understood to mean the wavelength range from about 760 nm to about 2800 nm.
s This invention describes a process, which preferably proceeds automatically, for determining the hydrophilicity of a surface in one or more places. The wettability of a surface with water may be determined in one or more places by this means. For example, the success of a to hydrophilizing treatment of plastics surfaces, prior to the lacquering thereof with water-based lacquers, for example, may be checked by such means. In particular, the process is suitable for checking the outcome of a cleaning of the solid surface, wherein hydrophobic surface i5 contaminants, such as fats or oils, are removed. The more hydrophilic the surface has been rendered by cleaning, i . a . the greater the average coverage of the surface with water after cleaning, the more completely have the hydrophobic contaminants been removed from the surface.
zo By this means, it is possible, for example, to check the success of a cleaning of objects made of metal, plastic, glass and/or ceramics, for example in the course of the manufacture or machining of such components. Furthermore, the present invention is also suitable, for example, for 2s verifying the success of the cleaning of crockery and/or trays in continuous cleaning units.
The present invention relates in particular to the field of cleaning hard surfaces in industrial production 3o processes. The present invention is applicable in particular to metal surfaces which are covered with anti-corrosive oils or with oils which facilitate shaping processes, such as rolling, forming, drawing, cold extrusion or machining. The present invention relates to 35 that part of an industrial production line in which this oil should be at least substantially removed from the surfaces by cleaning in order subsequently to subject the surfaces to a further treatment, such as a chemical conversion (conversion treatment) or a coating, for example. The conversion treatment may, for example, be phosphating, with or without film-forming, chromating, anodizing or a treatment using solutions which contain s transition metal ions and/or single-bonded and/or complexed fluorides and/or the acids thereof. An example of coating is coating using organic polymers or using those organic substances which crosslink and form polymers when heated and/or when irradiated with infrared, visible to or ultraviolet radiation (such as lacquering) or coating using metal coatings, such as coating with metallic zinc, nickel, chromium, aluminum or with alloys, at least 50% of which consist of the said elements in each case.
15 There is a multiplicity of industrial production processes in which metal strip or moulded parts made of metal are formed and/or joined and then cleaned in order to prepare the surface for further treatment steps, such as conversion treatment or coating. For the forming 2o processes, the surfaces are generally covered with rolling or forming oils which are to facilitate forming and, in particular, prevent bonding of the metal surface of the workpiece with the tool. Examples of such forming processes are non-cutting processes such as rolling, 2s bending, drawing or cold extrusion and processes which are not chipless, such as cutting, drilling or milling. If metallic materials are stored and/or transported between different processing stages it is conventional to protect the surfaces from corrosion by means of an anti-corrosive 30 oil. Before the further treatment steps of chemical conversion treatment and/or coating which have been exemplified above, these oils must be removed by means of suitable cleaner solutions at least so extensively that residual quantities of oil left behind on the surfaces do 35 not have a negative impact on the subsequent process steps. Successful cleaning is evident from the fact that, after cleaning, the surface is so hydrophilic that the water film on the surface after cleaning does not break up within a time interval to be specified, between 10 seconds and 2 minutes, for example, and the water does not run off more or less completely. A surface which has been s successfully cleaned using an aqueous cleaner solution is thus coated with an even water film after cleaning.
Traditionally a so-called "water break test" is carried out to check the hydrophilicity of the cleaned surface.
io This involves a visual assessment of the percentage of the surface which is not or is no longer wetted with water immediately after wetting or within up to about 2 minutes of wetting. The greater the percentage of non-wetted partial areas of the surface, the poorer the result of 15 cleaning. Although a visual assessment of this type is simple to carry out, staff need to be available to perform it. In the past, this test has conventionally been carried out on sample parts in the laboratory and not on the original workpieces in the production line.
It is known to determine the water content of solvents or the moisture content of products by determining the absorption by the sample of infrared radiation at one or more specified wavelengths. The specified wavelengths are 2s selected in such a way that water absorbs the infrared radiation particularly intensely at these wavelengths. As is known, by infrared radiation is meant that portion of the spectrum of electromagnetic radiation which adjoins the longwave limit of the sensitivity of the human eye at 3o about 760 nm. At wavelengths in the region of about 1 mm, infrared radiation becomes microwave radiation. In the narrower sense, the wavelength range between about 760 and about 15000 nm may be termed infrared radiation.
Wavelengths in the range of the so-called near infrared 35 radiation in particular are suitable for the quantitative determination of water. This may be understood to mean the wavelength range from about 760 nm to about 2800 nm.
In this range, water has a series of particularly marked absorption bands at about 1430, 1900 and 2720 nm.
Particulars on water determination by infrared absorption may be taken from the following review, for example: C
Jones, "Near-Infrared Analysis in the Process Industry", Analysis Instrumentation 28th Annual Symposium Abstracts, ISBN O-87664-687-9 (1982), pp. 21-25.
To the Applicant's knowledge, infrared absorption has not to yet been used to determine the hydrophilicity of a surface and particularly to check the outcome of a cleaning operation. Rather, the article by M Stiles, T Haasner, B
Haase: "Uberprufung der Reinigungsqualitat and Restschmutzbestimmung - Teil II", JOT (1988)7, pp. 58-63, i5 states that the water break test, described as the water run-off test here, cannot be carried out in the form of an on-line test.
The present invention relates to a process for checking 2o the hydrophilicity of a solid surface after a hydrophilizing treatment, wherein the surface is wetted with water, irradiated with infrared radiation, the intensity of the infrared radiation reflected back by the surface is measured at a specified wavelength or at 2s several specified wavelengths and the average coverage of the surface with water is determined from the intensity measured (optionally converted to absorption).
Preferably, this measurement is carried out in a time interval between about 10 seconds and about 2 minutes 3o after wetting the surface with water.
Infrared radiation at a specified wavelength or several specified wavelengths in the range between about 760 and about 2800 nm is preferably used for this process. Those 35 specified wavelengths at which water exhibits particularly intense absorption are preferably selected. Accordingly, it is preferred that the intensity of the infrared radiation reflected back by the surface is measured at one or more specified wavelengths in the region of 1430, 1900 and/or 2720 nm.
Particulars on water determination by infrared absorption may be taken from the following review, for example: C
Jones, "Near-Infrared Analysis in the Process Industry", Analysis Instrumentation 28th Annual Symposium Abstracts, ISBN O-87664-687-9 (1982), pp. 21-25.
To the Applicant's knowledge, infrared absorption has not to yet been used to determine the hydrophilicity of a surface and particularly to check the outcome of a cleaning operation. Rather, the article by M Stiles, T Haasner, B
Haase: "Uberprufung der Reinigungsqualitat and Restschmutzbestimmung - Teil II", JOT (1988)7, pp. 58-63, i5 states that the water break test, described as the water run-off test here, cannot be carried out in the form of an on-line test.
The present invention relates to a process for checking 2o the hydrophilicity of a solid surface after a hydrophilizing treatment, wherein the surface is wetted with water, irradiated with infrared radiation, the intensity of the infrared radiation reflected back by the surface is measured at a specified wavelength or at 2s several specified wavelengths and the average coverage of the surface with water is determined from the intensity measured (optionally converted to absorption).
Preferably, this measurement is carried out in a time interval between about 10 seconds and about 2 minutes 3o after wetting the surface with water.
Infrared radiation at a specified wavelength or several specified wavelengths in the range between about 760 and about 2800 nm is preferably used for this process. Those 35 specified wavelengths at which water exhibits particularly intense absorption are preferably selected. Accordingly, it is preferred that the intensity of the infrared radiation reflected back by the surface is measured at one or more specified wavelengths in the region of 1430, 1900 and/or 2720 nm.
5 Preferably the procedure is to arrange one or more sources of infrared radiation of suitable wavelength in the vicinity of the measuring element which measures the intensity of the infrared radiation reflected back by the portion of the surface under test. By means of several so radiation sources which are arranged round the measuring element for measuring the reflected infrared radiation, a particularly uniform irradiation of that portion of the surface whose coverage with water is to be measured may be achieved if required. This prevents or at least reduces i5 errors due to shadows.
The size of the measuring spot on the surface in the region of which the intensity of the infrared radiation is detected by the measuring element depends on the distance 2o between the measuring element and the surface, on the one hand and its angle of aperture, on the other hand. The further the distance between the element and the surface, the larger the region of the surface which is detected.
In order to be able to detect a sufficiently large portion 2s of the surface (about 3 x 4 cm, for example) when measuring the intensity of the infrared radiation and, on the other hand, to ensure that the intensity is measured with sufficient accuracy, it is advisable to provide a distance of about 18 to about 50 cm, about 20 to 30 cm for 3o example, between measuring element and surface. This means that the measurement on a reflecting surface is conducted in such a way that the surface is irradiated with infrared radiation at an angle of about 75? and the intensity of the radiation reflected back against the 35 direction of radiation is measured.
The size of the measuring spot on the surface in the region of which the intensity of the infrared radiation is detected by the measuring element depends on the distance 2o between the measuring element and the surface, on the one hand and its angle of aperture, on the other hand. The further the distance between the element and the surface, the larger the region of the surface which is detected.
In order to be able to detect a sufficiently large portion 2s of the surface (about 3 x 4 cm, for example) when measuring the intensity of the infrared radiation and, on the other hand, to ensure that the intensity is measured with sufficient accuracy, it is advisable to provide a distance of about 18 to about 50 cm, about 20 to 30 cm for 3o example, between measuring element and surface. This means that the measurement on a reflecting surface is conducted in such a way that the surface is irradiated with infrared radiation at an angle of about 75? and the intensity of the radiation reflected back against the 35 direction of radiation is measured.
In the context of the problem, it is not absolutely necessary precisely to determine the average coverage of the surface with water as mass of water per m2 of surface or as average film thickness of the water film, for s example. Rather, by comparison with readily wettable standard samples, it is generally sufficient to establish whether the intensity of the infrared radiation reflected by the surface after absorption of a part of the infrared radiation by the water adhering to the surface is in an to order of magnitude which is typical of a completely wettable surface. Accordingly, the procedure is to determine the average coverage of the surface with water by comparing the intensity of the infrared radiation reflected by the surface at at least one specified 15 wavelength with the intensity of the infrared radiation reflected by a standard surface wetted with water at the specified wavelength. It is, of course, desirable to test the standard surface and the surface to be tested under identical measurement conditions (intensity of the 2o infrared radiation source, distance between radiation source and measuring element and the surface). It is also advisable to use as the standard surface the same material as for the surface to be tested.
2s Accordingly, the process is suitable for determining the average coverage of a selected region of a surface with water. The more completely the selected region is covered with a water film, the greater the absorption of the surface for infrared radiation of suitable wavelength. A
3o break-up of the water film because of lack of hydrophilicity (poor cleaning) reduces the absorption for infrared radiation of suitable wavelength and thus increases the intensity of the infrared radiation reflected back at that wavelength. By comparison with the 3s intensity of infrared radiation reflected back by a completely wetted standard sample under corresponding measurement conditions, it is possible to establish whether the tested portion of the surface is completely or only partially covered with a water film. The weaker the absorption for infrared radiation of suitable wavelength, the less water there is on the measured part of the s surface. This means that either a thin, but even water film may be present or that a broken-up, but thicker water film is present which covers the surface only in places.
It is thus possible to establish the degree of wetting of the selected surface portion in per cent, for example, to with respect to complete wetting with a specified water film thickness.
The outcome of a cleaning step may therefore be verified, on the one hand, by establishing what percentage of a 15 selected portion of a surface is covered with a water film and/or what is the average thickness of the water film.
Alternatively, the intensity of the infrared radiation reflected by different places on the surface may be measured and compared with each other. This establishes 2o whether different, corresponding places on the surface are hydrophilic to different extents and have hence been cleaned to different degrees of satisfaction. In this embodiment, the process is suitable for establishing the uniformity of the cleaning result at different places on 2s the surface. Accordingly, an embodiment of the process according to the present invention is characterized in that differences in the hydrophilicity of a surface are determined at different places by irradiating the different places on the surface with infrared radiation, 3o measuring the intensity of the infrared radiation reflected back by the different places on the surface at a specified wavelength or at several specified wavelengths and comparing the intensities of the infrared radiation reflected back by the different places on the surface with 35 each other.
2s Accordingly, the process is suitable for determining the average coverage of a selected region of a surface with water. The more completely the selected region is covered with a water film, the greater the absorption of the surface for infrared radiation of suitable wavelength. A
3o break-up of the water film because of lack of hydrophilicity (poor cleaning) reduces the absorption for infrared radiation of suitable wavelength and thus increases the intensity of the infrared radiation reflected back at that wavelength. By comparison with the 3s intensity of infrared radiation reflected back by a completely wetted standard sample under corresponding measurement conditions, it is possible to establish whether the tested portion of the surface is completely or only partially covered with a water film. The weaker the absorption for infrared radiation of suitable wavelength, the less water there is on the measured part of the s surface. This means that either a thin, but even water film may be present or that a broken-up, but thicker water film is present which covers the surface only in places.
It is thus possible to establish the degree of wetting of the selected surface portion in per cent, for example, to with respect to complete wetting with a specified water film thickness.
The outcome of a cleaning step may therefore be verified, on the one hand, by establishing what percentage of a 15 selected portion of a surface is covered with a water film and/or what is the average thickness of the water film.
Alternatively, the intensity of the infrared radiation reflected by different places on the surface may be measured and compared with each other. This establishes 2o whether different, corresponding places on the surface are hydrophilic to different extents and have hence been cleaned to different degrees of satisfaction. In this embodiment, the process is suitable for establishing the uniformity of the cleaning result at different places on 2s the surface. Accordingly, an embodiment of the process according to the present invention is characterized in that differences in the hydrophilicity of a surface are determined at different places by irradiating the different places on the surface with infrared radiation, 3o measuring the intensity of the infrared radiation reflected back by the different places on the surface at a specified wavelength or at several specified wavelengths and comparing the intensities of the infrared radiation reflected back by the different places on the surface with 35 each other.
Appropriately surfaces which are inclined with respect to the horizontal at least to the extent that water may run off hydrophobic regions of the surface are selected for the process according to the present invention.
s Accordingly, the surface should not be precisely horizontal. Rather, it is appropriate for the surface to be inclined to the horizontal by an angle of > 10? in the time period between wetting with water and taking the measurement of the infrared radiation reflected back by to the surface. Furthermore it is appropriate always to allow approximately equal periods of time to elapse between wetting with water and taking the measurement.
The process according to the present invention may be is used, for example, to check the success of a hydrophilizing surface treatment of plastics (treatment with strong chemical oxidants, with a plasma or with ionizing radiation for example). If this hydrophilizing treatment is not carried out by means of an aqueous 2o solution, for the process according to the present invention it is necessary to wet the surface with water.
If the process according to the present invention is implemented in order to check the success of a cleaning of the surface using an aqueous cleaner solution, the 2s cleaning process may itself represent the wetting step.
Accordingly, in this case the surface is wetted with water in that it is cleaned using an aqueous cleaner solution.
The process according to the present invention is intended 3o in particular for use in production processes in which the surface in question is a metal surface which is subj ected to a chemical conversion (= conversion treatment) or coating after cleaning. The introductory part of this disclosure has already explained what may be understood by 3s a "chemical conversion" or "coating". Accordingly, the process may be used in particular in the manufacture of coated steel strip, in vehicle construction and in the domestic appliances industry. In particular it is intended that the surface in question is the surface of a vehicle, such as a motor car, or the surface of a vehicle component, which is phosphated after cleaning. Film-s forming phosphating processes are carried out in particular, such as low-zinc phosphating, which is currently conventionally effected.
If the process is applied to motor vehicle bodies which to are cleaned after assembly and then phosphated, it may be provided that the process according to the present invention is applied to several places on the vehicle body. It is possible to establish whether the cleaner solution has a uniformly satisfactory action on all parts 15 of the vehicle body. This may be important in particular where, as is quite conventional, different vehicle components are made of different materials perhaps by different manufacturers, these different materials possibly being covered with different oils.
As quality assurance is of particular importance to vehicle construction, in the course of the process according to the present invention provision is preferably made for the results of the determination of the 2s hydrophilicity to be stored in such a way that the reference to the checked vehicle or vehicle component is retained. Bar codes which serve to identify the vehicle and/or vehicle component which has just been measured may be fitted to the transport devices for the vehicles and/or 3o vehicle components for this purpose, for example. In the event of subsequent complaints, it is then possible to trace back and find out the result of the cleaning of the vehicle and/or vehicle component in question.
35 A distinction may be made between two instances as regards a relative movement of the surface, the hydrophilicity of which is to be determined, with respect to the measuring element for the infrared radiation: provision may be made for the surface not to move relative to the measuring element which measures the intensity of the infrared radiation during the measurement time; provision may, s however, also be made for the surface to move relative to the measuring element which measures the intensity of the infrared radiation during the measurement time. In the industrial production processes exemplified, it is usual for the components and/or the metal strips to move through io the individual treatment zones more or less uniformly. If the tested surface portion is not desired to move with respect to the measuring element when the measurement is being taken, it is therefore necessary for the measuring element to move at the same speed and in the same direction as the portion of the surface under test.
Alternatively, however, provision may also be made for the surface to move relative to the measuring element which measures the intensity of the infrared radiation while the 2o measurement is being taken. In this embodiment the measuring element is mounted in fixed manner and the component, the surface hydrophilicity of which is to be tested, moves past the measuring element. During the measurement time, which may conventionally be in the 2s region of a few seconds (about 1 to about 10 seconds) , a larger portion of the surface than corresponds to the actual measurement spot is detected by this means.
Information is thus obtained about the average water coverage of that portion of the surface which moves past 3o the measuring element during the measurement time.
Using an identical measurement time, therefore, in the case of the surface which is stationary with respect to the measuring element, a smaller portion of the surface is 35 checked than in the case of the surface moved relative to the measuring element. The same effect, viz the detection of surface portions of variable size, could also be achieved by changing the distance between the measuring element and the surface. This is less advisable, however, because the intensity of the infrared radiation reaching the measuring element decreases as the distance between the measuring element and the surface increases. This could be partially compensated by longer measurement times, but using this procedure it would be advisable to calibrate the measuring instrument for every distance between the measuring element and the surface. This means to greater outlay, but does not convey substantial advantages.
If the time in which the surface of a component, such as a motor vehicle body, passes by the measuring element is divided into different measurement sections, it is possible to compare whether the same coverage with water is detected in each measurement section (each of which corresponds to another portion of the surface).
Irregularities in the result of the cleaning operation may 2o also be established by this means.
The same applies to the case in which the process is used to check the hydrophilicity of a plastics surface after a hydrophilizing treatment.
The process according to the present invention preferably provides that, controlled by a control system, the determination of the hydrophilicity of the surface proceeds automatically under program control and the 3o result of the determination is outputted locally or at a remote location or is stored on a data carrier for further processing and/or, depending on the result of the determination, a warning signal is generated locally or at a remote location and/or a check of the composition of the cleaner solution used to clean the surfaces is automatically initiated if the hydrophilizing treatment of the surface involves the cleaning thereof.
In this embodiment, the process according to the present invention serves to check a hydrophilizing treatment of a surface, such as a cleaning of hydrophobic contaminants, without human intervention being required. The process according to the present invention may therefore be used in a continuous production process without human labor being committed to carry it out. The process may be used to check the result of a cleaning step, i.e. to determine how completely a surface is wettable after cleaning.
to Depending on the embodiment of the process, the result may be outputted either locally or at a remote location.
Furthermore, it may be stored on a data carrier for further processing, such as to identify trends or as records in the context of quality assurance. Furthermore, i5 provision may be made for one or more specified measures to be carried out further to the detection of a specified amount of unwetted surface after cleaning. A warning signal may be generated locally or at a remote location, for example. This may be an optical or an acoustic signal 20 or a display on a screen. Furthermore, depending on the result of the determination of wettability, a check of the composition of the cleaner solution may be automatically initiated, which may optionally lead to components of the cleaning solution being topped up automatically or z5 measures to attend to and/or renew the cleaner solution being initiated.
In this embodiment, the present invention is particularly suitable for determining the wettability of a surface 3o after the surface has been cleaned using a cleaner solution. For the implementation of the process of the present invention, it is immaterial which of the cleaner solutions known from the prior art is used for this purpose.
It is an advantageous aspect of the present invention that the result of the check of the hydrophilicity of the surface may be outputted not only locally, but also at a remote location. The term "remote location" is intended to indicate a location which is not in immediate or at least in visual contact with the control system which s controls the process according to the present invention.
The remote location may, for example, be a central process control system which checks the outcome of the cleaning step as a task in the context of an overall process for the surface treatment of metal parts, for example, and io optionally gives instructions to check the cleaner solution. The remote location may also be a central control room from which the entire process is supervised and controlled and which is located, for example, in a different room from the cleaner bath, the cleaning 15 performance of which is to be checked. A location outside the factory in which the cleaning step is performed may, however, also be regarded as a remote location. By this means, it is possible for skilled workers to check the success of the cleaning step and optionally institute 2o measures to regenerate the cleaner solution without being in the spatial vicinity of the cleaner solution. This means that there is a substantially less frequent need for specialized personnel to be in the same location as the cleaner solution.
For quality assurance purposes, provision may also be made for the allocation of the measurement result to the checked workpiece, for example a motor vehicle body, to be retained and stored on a data carrier. This may take 3o place, for example, in that the workpiece is provided with a characteristic marking, such as a bar code, by the automatic reading of which the workpiece which has been checked may be identified.
A further substantial aspect of the present invention resides, however, in the fact that, depending on the result of the check of the hydrophilicity of the surface, the control system for the process instigates a check of its own accord and, as a result thereof, action is initiated to regenerate the cleaner solution, if required, without human intervention being required.
An inadequate outcome of a cleaning operation may be defined according to different specified criteria: a tolerance range within which the average coverage of the cleaned surface with water should generally lie may be to specified. Furthermore, a check range may be specified in which the average coverage with water may only lie in a specified limited number of cases, related to the number of determinations carried out or to time, for example. If average coverage with water is more frequently in the check range, the system will initiate one or more of the pre-selected measures. A trend analysis may also be provided at the same time. As the result of this trend analysis, provision may be made for measures to be initiated if the number of cases in which the average zo coverage with water lies in the control range increases with time. Also, a lower limit for average coverage with water may be established, below which one or more of the measures provided is automatically initiated in any event.
z5 The selectable measures which the control system may initiate for the process according to the present invention have already been mentioned above. In particular, provision may be made for the control system to initiate the determination of one or more parameters of 3o the cleaning solution of its own accord. For example, the control system may initiate a determination of the alkalinity, surfactant content and/or oil contamination of the cleaner solution or also several of these determinations. The way in which these determinations are 3s carried out automatically is described, for example, in German Patent Applications 198 02 725, 198 14 500, 198 20 800 and 198 36 720. Depending on the outcome of the analysis of the composition of the cleaner solution, further measures, such as topping up components of the cleaner solution, purifying or renewing it, may preferably be automatically instigated and implemented. These s measures which restore the functionality of the cleaner solution are also described in the said German Patent Applications 198 02 725, 198 14 500, 198 20 800 and 198 36 720.
to Regardless of which measures for checking and regenerating the cleaner solution the control system initiates, it is advisable to record the performance of these measures and the results thereof on a data carrier for future evaluation and to display them locally and/or at a remote 15 location.
As a most extreme measure, provision may be made for the entire production process to be stopped and a corresponding alarm warning to be outputted locally and/or 2o at a remote location below a certain threshold value for average coverage with water.
The process according to the present invention preferably provides that the measuring instrument used conducts a z5 self-test of functionality after specified time intervals, which may be in the range between an hour and a day, for example, after a specified number of measurements, such as after every tenth to hundredth measurement, or when the results of two measurements differ from each other by a 3o specified minimum value. This may reduce the risk of an alarm or a more serious measure being initiated because the measuring instrument is faulty. Preferably the result of the self-test of the measuring instrument is retained on a data carrier for a future check or for quality 35 assurance purposes.
The test may be carried out, for example, in that a dry test piece, the nature of which corresponds to the workpieces tested, is placed in the path of the rays of the measuring instrument. The infrared radiation s reflected back by the surface of this test body provides the maximum intensity value and/or the minimum absorption value. One or more filters which have a specified absorption capacity for infrared radiation may then be placed in the path of the rays. The measuring instrument to checks whether it is actually measuring the expected absorption values (which must, of course, be stored in the unit's control system). If the measured absorption through the filters differs from the expected value by a specified minimum value, this indicates a malfunction in 15 the measuring instrument. In this case provision is preferably made for an alarm to be outputted locally and/or at a remote location with the instruction to check the measuring instrument. In this case provision is also preferably made for the control system for the process to 2o discontinue the further implementation of the process until the measuring instrument has been checked.
The process according to the present invention thus has the partial aspect that the success of a hydrophilizing 2s surface treatment, particularly a surface cleaning, is checked largely independently of human intervention. If inadequate cleaning results are established or if a trend is indicated to the effect that the cleaning results are increasingly deteriorating although they are still within 3o the tolerance range, a check of the composition of the cleaner solution may be instigated automatically and, as a result of this check components may be added to the cleaner solution or bath maintenance measures for the cleaner solution initiated. By this means, it is possible 35 to guarantee consistent quality in an industrial production line largely without human supervision. The information obtained during the period of use of the process according to the present invention and the measures carried out are preferably stored on data carriers and are available for quality assurance purposes, for future evaluation and for collecting data for the s control system. The control system may be designed to be adaptive by this means. By transferring the data acquired in the course of the process according to the present invention to a remote location, it is possible also to check the success of the cleaning step from a remote to location. The process according to the present invention thus increases production reliability, on the one hand, and reduces manual outlay in that respect, on the other hand.
15 Example The process according to the present invention was verified on a continuous cleaning unit for sheet metal test pieces (dimensions 10 x 20 cm) such as are 2o conventional for checking surface treatment processes in motor vehicle construction. Sheet metal test pieces made of different materials conventional in motor vehicle construction were used: cold-rolled steel, hot dip galvanized steel, aluminum, pre-phosphated steel. The 25 radiation source for the infrared radiation and the measuring element for the infrared radiation reflected back by the sheet metal test pieces were positioned in such a way that the damp sheets were transported past the radiation source and measuring element after cleaning. A
3o tungsten halogen lamp was used as the radiation source.
It provided infrared radiation in a wavelength range from 700 to 2000 nm. A lead sulfide detector served as the measuring element for the infrared radiation reflected back by the sheet metal test pieces. The intensity 35 measurement was made at 1921 nm, wherein the radiation of 1703 nm was used as intensity reference. The particular wavelengths were selected by filters.
The sheet metal test pieces wetted with water and passing in front of the measuring element led to a characteristic attenuation of the infrared radiation registered by the measuring element at the pre-selected wavelength. This s characteristic attenuation was substantially constant for sheet metal test pieces of one material type. In individual sheet metal test pieces, an unsatisfactory cleaning result would have been identifiable by the fact that considerably less attenuation of the infrared to radiation reflected back by the surface at the specified wavelength would have been detected, corresponding to a considerably smaller average thickness of the water film.
This was the case with sheets which had not been cleaned, for example.
s Accordingly, the surface should not be precisely horizontal. Rather, it is appropriate for the surface to be inclined to the horizontal by an angle of > 10? in the time period between wetting with water and taking the measurement of the infrared radiation reflected back by to the surface. Furthermore it is appropriate always to allow approximately equal periods of time to elapse between wetting with water and taking the measurement.
The process according to the present invention may be is used, for example, to check the success of a hydrophilizing surface treatment of plastics (treatment with strong chemical oxidants, with a plasma or with ionizing radiation for example). If this hydrophilizing treatment is not carried out by means of an aqueous 2o solution, for the process according to the present invention it is necessary to wet the surface with water.
If the process according to the present invention is implemented in order to check the success of a cleaning of the surface using an aqueous cleaner solution, the 2s cleaning process may itself represent the wetting step.
Accordingly, in this case the surface is wetted with water in that it is cleaned using an aqueous cleaner solution.
The process according to the present invention is intended 3o in particular for use in production processes in which the surface in question is a metal surface which is subj ected to a chemical conversion (= conversion treatment) or coating after cleaning. The introductory part of this disclosure has already explained what may be understood by 3s a "chemical conversion" or "coating". Accordingly, the process may be used in particular in the manufacture of coated steel strip, in vehicle construction and in the domestic appliances industry. In particular it is intended that the surface in question is the surface of a vehicle, such as a motor car, or the surface of a vehicle component, which is phosphated after cleaning. Film-s forming phosphating processes are carried out in particular, such as low-zinc phosphating, which is currently conventionally effected.
If the process is applied to motor vehicle bodies which to are cleaned after assembly and then phosphated, it may be provided that the process according to the present invention is applied to several places on the vehicle body. It is possible to establish whether the cleaner solution has a uniformly satisfactory action on all parts 15 of the vehicle body. This may be important in particular where, as is quite conventional, different vehicle components are made of different materials perhaps by different manufacturers, these different materials possibly being covered with different oils.
As quality assurance is of particular importance to vehicle construction, in the course of the process according to the present invention provision is preferably made for the results of the determination of the 2s hydrophilicity to be stored in such a way that the reference to the checked vehicle or vehicle component is retained. Bar codes which serve to identify the vehicle and/or vehicle component which has just been measured may be fitted to the transport devices for the vehicles and/or 3o vehicle components for this purpose, for example. In the event of subsequent complaints, it is then possible to trace back and find out the result of the cleaning of the vehicle and/or vehicle component in question.
35 A distinction may be made between two instances as regards a relative movement of the surface, the hydrophilicity of which is to be determined, with respect to the measuring element for the infrared radiation: provision may be made for the surface not to move relative to the measuring element which measures the intensity of the infrared radiation during the measurement time; provision may, s however, also be made for the surface to move relative to the measuring element which measures the intensity of the infrared radiation during the measurement time. In the industrial production processes exemplified, it is usual for the components and/or the metal strips to move through io the individual treatment zones more or less uniformly. If the tested surface portion is not desired to move with respect to the measuring element when the measurement is being taken, it is therefore necessary for the measuring element to move at the same speed and in the same direction as the portion of the surface under test.
Alternatively, however, provision may also be made for the surface to move relative to the measuring element which measures the intensity of the infrared radiation while the 2o measurement is being taken. In this embodiment the measuring element is mounted in fixed manner and the component, the surface hydrophilicity of which is to be tested, moves past the measuring element. During the measurement time, which may conventionally be in the 2s region of a few seconds (about 1 to about 10 seconds) , a larger portion of the surface than corresponds to the actual measurement spot is detected by this means.
Information is thus obtained about the average water coverage of that portion of the surface which moves past 3o the measuring element during the measurement time.
Using an identical measurement time, therefore, in the case of the surface which is stationary with respect to the measuring element, a smaller portion of the surface is 35 checked than in the case of the surface moved relative to the measuring element. The same effect, viz the detection of surface portions of variable size, could also be achieved by changing the distance between the measuring element and the surface. This is less advisable, however, because the intensity of the infrared radiation reaching the measuring element decreases as the distance between the measuring element and the surface increases. This could be partially compensated by longer measurement times, but using this procedure it would be advisable to calibrate the measuring instrument for every distance between the measuring element and the surface. This means to greater outlay, but does not convey substantial advantages.
If the time in which the surface of a component, such as a motor vehicle body, passes by the measuring element is divided into different measurement sections, it is possible to compare whether the same coverage with water is detected in each measurement section (each of which corresponds to another portion of the surface).
Irregularities in the result of the cleaning operation may 2o also be established by this means.
The same applies to the case in which the process is used to check the hydrophilicity of a plastics surface after a hydrophilizing treatment.
The process according to the present invention preferably provides that, controlled by a control system, the determination of the hydrophilicity of the surface proceeds automatically under program control and the 3o result of the determination is outputted locally or at a remote location or is stored on a data carrier for further processing and/or, depending on the result of the determination, a warning signal is generated locally or at a remote location and/or a check of the composition of the cleaner solution used to clean the surfaces is automatically initiated if the hydrophilizing treatment of the surface involves the cleaning thereof.
In this embodiment, the process according to the present invention serves to check a hydrophilizing treatment of a surface, such as a cleaning of hydrophobic contaminants, without human intervention being required. The process according to the present invention may therefore be used in a continuous production process without human labor being committed to carry it out. The process may be used to check the result of a cleaning step, i.e. to determine how completely a surface is wettable after cleaning.
to Depending on the embodiment of the process, the result may be outputted either locally or at a remote location.
Furthermore, it may be stored on a data carrier for further processing, such as to identify trends or as records in the context of quality assurance. Furthermore, i5 provision may be made for one or more specified measures to be carried out further to the detection of a specified amount of unwetted surface after cleaning. A warning signal may be generated locally or at a remote location, for example. This may be an optical or an acoustic signal 20 or a display on a screen. Furthermore, depending on the result of the determination of wettability, a check of the composition of the cleaner solution may be automatically initiated, which may optionally lead to components of the cleaning solution being topped up automatically or z5 measures to attend to and/or renew the cleaner solution being initiated.
In this embodiment, the present invention is particularly suitable for determining the wettability of a surface 3o after the surface has been cleaned using a cleaner solution. For the implementation of the process of the present invention, it is immaterial which of the cleaner solutions known from the prior art is used for this purpose.
It is an advantageous aspect of the present invention that the result of the check of the hydrophilicity of the surface may be outputted not only locally, but also at a remote location. The term "remote location" is intended to indicate a location which is not in immediate or at least in visual contact with the control system which s controls the process according to the present invention.
The remote location may, for example, be a central process control system which checks the outcome of the cleaning step as a task in the context of an overall process for the surface treatment of metal parts, for example, and io optionally gives instructions to check the cleaner solution. The remote location may also be a central control room from which the entire process is supervised and controlled and which is located, for example, in a different room from the cleaner bath, the cleaning 15 performance of which is to be checked. A location outside the factory in which the cleaning step is performed may, however, also be regarded as a remote location. By this means, it is possible for skilled workers to check the success of the cleaning step and optionally institute 2o measures to regenerate the cleaner solution without being in the spatial vicinity of the cleaner solution. This means that there is a substantially less frequent need for specialized personnel to be in the same location as the cleaner solution.
For quality assurance purposes, provision may also be made for the allocation of the measurement result to the checked workpiece, for example a motor vehicle body, to be retained and stored on a data carrier. This may take 3o place, for example, in that the workpiece is provided with a characteristic marking, such as a bar code, by the automatic reading of which the workpiece which has been checked may be identified.
A further substantial aspect of the present invention resides, however, in the fact that, depending on the result of the check of the hydrophilicity of the surface, the control system for the process instigates a check of its own accord and, as a result thereof, action is initiated to regenerate the cleaner solution, if required, without human intervention being required.
An inadequate outcome of a cleaning operation may be defined according to different specified criteria: a tolerance range within which the average coverage of the cleaned surface with water should generally lie may be to specified. Furthermore, a check range may be specified in which the average coverage with water may only lie in a specified limited number of cases, related to the number of determinations carried out or to time, for example. If average coverage with water is more frequently in the check range, the system will initiate one or more of the pre-selected measures. A trend analysis may also be provided at the same time. As the result of this trend analysis, provision may be made for measures to be initiated if the number of cases in which the average zo coverage with water lies in the control range increases with time. Also, a lower limit for average coverage with water may be established, below which one or more of the measures provided is automatically initiated in any event.
z5 The selectable measures which the control system may initiate for the process according to the present invention have already been mentioned above. In particular, provision may be made for the control system to initiate the determination of one or more parameters of 3o the cleaning solution of its own accord. For example, the control system may initiate a determination of the alkalinity, surfactant content and/or oil contamination of the cleaner solution or also several of these determinations. The way in which these determinations are 3s carried out automatically is described, for example, in German Patent Applications 198 02 725, 198 14 500, 198 20 800 and 198 36 720. Depending on the outcome of the analysis of the composition of the cleaner solution, further measures, such as topping up components of the cleaner solution, purifying or renewing it, may preferably be automatically instigated and implemented. These s measures which restore the functionality of the cleaner solution are also described in the said German Patent Applications 198 02 725, 198 14 500, 198 20 800 and 198 36 720.
to Regardless of which measures for checking and regenerating the cleaner solution the control system initiates, it is advisable to record the performance of these measures and the results thereof on a data carrier for future evaluation and to display them locally and/or at a remote 15 location.
As a most extreme measure, provision may be made for the entire production process to be stopped and a corresponding alarm warning to be outputted locally and/or 2o at a remote location below a certain threshold value for average coverage with water.
The process according to the present invention preferably provides that the measuring instrument used conducts a z5 self-test of functionality after specified time intervals, which may be in the range between an hour and a day, for example, after a specified number of measurements, such as after every tenth to hundredth measurement, or when the results of two measurements differ from each other by a 3o specified minimum value. This may reduce the risk of an alarm or a more serious measure being initiated because the measuring instrument is faulty. Preferably the result of the self-test of the measuring instrument is retained on a data carrier for a future check or for quality 35 assurance purposes.
The test may be carried out, for example, in that a dry test piece, the nature of which corresponds to the workpieces tested, is placed in the path of the rays of the measuring instrument. The infrared radiation s reflected back by the surface of this test body provides the maximum intensity value and/or the minimum absorption value. One or more filters which have a specified absorption capacity for infrared radiation may then be placed in the path of the rays. The measuring instrument to checks whether it is actually measuring the expected absorption values (which must, of course, be stored in the unit's control system). If the measured absorption through the filters differs from the expected value by a specified minimum value, this indicates a malfunction in 15 the measuring instrument. In this case provision is preferably made for an alarm to be outputted locally and/or at a remote location with the instruction to check the measuring instrument. In this case provision is also preferably made for the control system for the process to 2o discontinue the further implementation of the process until the measuring instrument has been checked.
The process according to the present invention thus has the partial aspect that the success of a hydrophilizing 2s surface treatment, particularly a surface cleaning, is checked largely independently of human intervention. If inadequate cleaning results are established or if a trend is indicated to the effect that the cleaning results are increasingly deteriorating although they are still within 3o the tolerance range, a check of the composition of the cleaner solution may be instigated automatically and, as a result of this check components may be added to the cleaner solution or bath maintenance measures for the cleaner solution initiated. By this means, it is possible 35 to guarantee consistent quality in an industrial production line largely without human supervision. The information obtained during the period of use of the process according to the present invention and the measures carried out are preferably stored on data carriers and are available for quality assurance purposes, for future evaluation and for collecting data for the s control system. The control system may be designed to be adaptive by this means. By transferring the data acquired in the course of the process according to the present invention to a remote location, it is possible also to check the success of the cleaning step from a remote to location. The process according to the present invention thus increases production reliability, on the one hand, and reduces manual outlay in that respect, on the other hand.
15 Example The process according to the present invention was verified on a continuous cleaning unit for sheet metal test pieces (dimensions 10 x 20 cm) such as are 2o conventional for checking surface treatment processes in motor vehicle construction. Sheet metal test pieces made of different materials conventional in motor vehicle construction were used: cold-rolled steel, hot dip galvanized steel, aluminum, pre-phosphated steel. The 25 radiation source for the infrared radiation and the measuring element for the infrared radiation reflected back by the sheet metal test pieces were positioned in such a way that the damp sheets were transported past the radiation source and measuring element after cleaning. A
3o tungsten halogen lamp was used as the radiation source.
It provided infrared radiation in a wavelength range from 700 to 2000 nm. A lead sulfide detector served as the measuring element for the infrared radiation reflected back by the sheet metal test pieces. The intensity 35 measurement was made at 1921 nm, wherein the radiation of 1703 nm was used as intensity reference. The particular wavelengths were selected by filters.
The sheet metal test pieces wetted with water and passing in front of the measuring element led to a characteristic attenuation of the infrared radiation registered by the measuring element at the pre-selected wavelength. This s characteristic attenuation was substantially constant for sheet metal test pieces of one material type. In individual sheet metal test pieces, an unsatisfactory cleaning result would have been identifiable by the fact that considerably less attenuation of the infrared to radiation reflected back by the surface at the specified wavelength would have been detected, corresponding to a considerably smaller average thickness of the water film.
This was the case with sheets which had not been cleaned, for example.
Claims (13)
1. A process for checking the hydrophilicity of a solid surface following a hydrophilizing treatment, the surface being wetted with water and exposed to infrared radiation, the intensity of the infrared radiation reflected by the surface being measured at a specified wavelength or at two or more specified wavelengths, and the average coverage of the surface with water being determined from the measured intensity, characterized in that the determination of the hydrophilicity of the surface proceeds automatically under program control and the result of the determination is output locally or at a remote location or is stored on a data carrier for further processing and/or depending on the result of the determination an alarm signal is produced locally or at a remote location and/or, where the hydrophilizing treatment of the surface comprises its cleaning, a review of the composition of the cleaning solution used to clean the surfaces is automatically initiated.
2. The process as claimed in claim 1, characterized in that the intensity of the infrared radiation reflected by the surface is measured at one or more specified wavelengths in the range between 760 and 2800 nm.
3. The process as claimed in claim 2, characterized in that the intensity of the infrared radiation reflected by the surface is measured at one or more specified wavelengths in the region of 1430, 1900 and/or 2720 nm.
4. The process as claimed in one or more of claims 1 to 3, characterized in that the average coverage of the surface with water is determined by comparing the intensity of the infrared radiation reflected by the surface and at least one specified wavelength with the intensity of the infrared radiation reflected by a standard surface, wetted with water, at the specified wavelength.
5. The process as claimed in one or more of claims 1 to 3, characterized in that differences in the hydrophilicity of the surface at different points are determined by exposing the different points of the surface to infrared radiation, measuring the intensity of the infrared radiation reflected by the different points of the surface at a specified wavelength or at two or more specified wavelengths, and comparing with one another the intensities of the infrared radiation reflected via the different points of the surface.
6. The process as claimed in one or more of claims 1 to 5, characterized in that the surface is inclined by an angle of greater than 10° to the horizontal in the period between the wetting with water and the implementation of the measurement of the infrared radiation reflected by the surface.
7. The process as claimed in one or more of claims 1 to 6, characterized in that the hydrophilizing treatment of the surface comprises cleaning it with an aqueous cleaning solution.
8. The process as claimed in claim 7, characterized in that the surface comprises a metallic surface which, following cleaning, is subjected to a chemical conversion or to coating.
9. The process as claimed in claim 8, characterized in that the surface is the surface of a motor vehicle or of a motor vehicle part which is phosphated after cleaning.
10. The process as claimed in one or more of claims 1 to 6, characterized in that the hydrophilicity of a plastics surface is checked after a hydrophilizing treatment.
11. The process as claimed in one or more of claims 1 to 10, characterized in that during the measurement of the intensity of the infrared radiation reflected by the surface the surface does not move relative to the measuring element which measures the intensity of the infrared radiation reflected by the surface.
12. The process as claimed in one or more of claims 1 to 10, characterized in that during measurement of the intensity of the infrared radiation reflected by the surface the surface moves relative to the measuring element which measures the intensity of the infrared radiation reflected by the surface.
13. The process as claimed in one or more of claims 1 to 12, characterized in that following specified intervals of time, following a specified number of measurements, or when the results of two measurements differ from one another by a specified minimum amount the measuring means used examines itself for functional capacity.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19855957.7 | 1998-12-04 | ||
| DE19855957A DE19855957B4 (en) | 1998-12-04 | 1998-12-04 | Automatic control of the hydrophilicity of a solid surface with infrared spectroscopy |
| PCT/EP1999/007367 WO2000034737A1 (en) | 1998-12-04 | 1999-10-05 | Automatic control of the hydrophilicity of a solid surface by infrared spectroscopy |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2353600A1 true CA2353600A1 (en) | 2000-06-15 |
Family
ID=7889951
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002353600A Abandoned CA2353600A1 (en) | 1998-12-04 | 1999-10-05 | Automatic check of the hydrophilicity of a solid surface using infrared spectroscopy |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP1056986A1 (en) |
| JP (1) | JP2002531855A (en) |
| KR (1) | KR20010090007A (en) |
| AR (1) | AR021530A1 (en) |
| AU (1) | AU1033300A (en) |
| CA (1) | CA2353600A1 (en) |
| CZ (1) | CZ20011980A3 (en) |
| DE (1) | DE19855957B4 (en) |
| WO (1) | WO2000034737A1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4586561B2 (en) * | 2005-02-15 | 2010-11-24 | Ｊｆｅスチール株式会社 | Aqueous solution measuring device |
| DE102014209862A1 (en) * | 2014-05-23 | 2015-11-26 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Method and device for determining a surface quality |
| DE102021100216A1 (en) | 2021-01-08 | 2022-07-14 | Universität Kassel, Körperschaft des öffentlichen Rechts | Method for monitoring the coverage of a mold surface of a mold with a process aid in a casting process |
| CN113029759B (en) * | 2021-03-31 | 2022-11-01 | 江西中科高博科技服务有限公司 | Cable performance detection device |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1303819C2 (en) * | 1964-05-29 | 1973-07-12 | DEVICE FOR MEASURING A COATING THICKNESS ON SURFACES | |
| GB1302196A (en) * | 1969-04-23 | 1973-01-04 | ||
| US3675019A (en) * | 1971-03-19 | 1972-07-04 | Measurex Corp | Apparatus for measuring the amount of a substance that is associated with a base material |
| JPS61120004A (en) * | 1984-11-16 | 1986-06-07 | Toshiba Electron Syst Kk | Measuring instrument for amount of water and ink |
| US4789564A (en) * | 1987-03-31 | 1988-12-06 | Union Carbide Corporation | Hydridoaminosilane treatment for rendering surfaces water-repellent |
| US5250811A (en) * | 1991-12-20 | 1993-10-05 | Eastman Kodak Company | Method for determining compositional information of a multilayer web |
| US5406082A (en) * | 1992-04-24 | 1995-04-11 | Thiokol Corporation | Surface inspection and characterization system and process |
| US5397397A (en) * | 1992-09-18 | 1995-03-14 | Crestek, Inc. | Method for cleaning and drying of metallic and nonmetallic surfaces |
| DE69313787T2 (en) * | 1992-11-12 | 1998-04-09 | Matsushita Electric Ind Co Ltd | Hydrophilic, thin coating and process for its manufacture |
| US5567444A (en) * | 1993-08-30 | 1996-10-22 | Ecolab Inc. | Potentiated aqueous ozone cleaning and sanitizing composition for removal of a contaminating soil from a surface |
| DE19802725C1 (en) * | 1998-01-24 | 1999-11-11 | Henkel Kgaa | Automatic control and control of detergent baths by determining the alkalinity |
| DE19814500A1 (en) * | 1998-04-01 | 1999-10-14 | Henkel Kgaa | Automatic control and regulation of the surfactant content in aqueous process solutions |
| DE19820800C2 (en) * | 1998-05-09 | 2001-06-28 | Henkel Kgaa | Automatic determination of the load of aqueous cleaning solutions with carbon-containing compounds |
| DE19836720A1 (en) * | 1998-08-13 | 2000-02-17 | Henkel Kgaa | Automatic testing and control of cleaning baths, as used in metal processing, e.g. for cleaning metal pieces before anti-corrosion processes |
-
1998
- 1998-12-04 DE DE19855957A patent/DE19855957B4/en not_active Expired - Fee Related
-
1999
- 1999-10-05 KR KR1020017005114A patent/KR20010090007A/en not_active Application Discontinuation
- 1999-10-05 WO PCT/EP1999/007367 patent/WO2000034737A1/en not_active Application Discontinuation
- 1999-10-05 CA CA002353600A patent/CA2353600A1/en not_active Abandoned
- 1999-10-05 JP JP2000587148A patent/JP2002531855A/en active Pending
- 1999-10-05 CZ CZ20011980A patent/CZ20011980A3/en unknown
- 1999-10-05 EP EP99948586A patent/EP1056986A1/en not_active Withdrawn
- 1999-10-05 AU AU10333/00A patent/AU1033300A/en not_active Abandoned
- 1999-12-03 AR ARP990106153A patent/AR021530A1/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| EP1056986A1 (en) | 2000-12-06 |
| KR20010090007A (en) | 2001-10-17 |
| AR021530A1 (en) | 2002-07-24 |
| JP2002531855A (en) | 2002-09-24 |
| CZ20011980A3 (en) | 2001-10-17 |
| WO2000034737A1 (en) | 2000-06-15 |
| AU1033300A (en) | 2000-06-26 |
| DE19855957A1 (en) | 2000-06-08 |
| DE19855957B4 (en) | 2008-10-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5264995B2 (en) | How to measure the cleanliness of steel strips | |
| US5289266A (en) | Noncontact, on-line determination of phosphate layer thickness and composition of a phosphate coated surface | |
| US10739286B2 (en) | Method for coating a surface of a metal strip and a metal strip-coating device | |
| CA2353600A1 (en) | Automatic check of the hydrophilicity of a solid surface using infrared spectroscopy | |
| WO2000022421A1 (en) | Automatic detection of oil and determination of oil residues | |
| US8345228B2 (en) | Measuring device and method for determining optical characteristic variables for verifying photochemical and electrochemical degradative reactions | |
| US4985622A (en) | Method for determining the corrosion resistance of deep-drawable iron sheets for body parts of motor vehicles and apparatus for performing the method | |
| MXPA01005487A (en) | Automatic control of the hydrophilicity of a solid surface by infrared spectroscopy | |
| JP3331169B2 (en) | Measurement method of oil amount on steel sheet surface | |
| JP4513425B2 (en) | Evaluation method of press formability of galvanized steel sheet | |
| JP2022512428A (en) | How to measure the crystallinity of a polymer coating on a metal substrate | |
| AU626201B2 (en) | Non-contact on-line determination of phosphate layer thickness and composition of a phosphate coated surface | |
| EP3798618A1 (en) | Surface analysis tools for process control of laser treatment of composites | |
| KR970010978B1 (en) | Phosphorus quantitative analysis method in zinc coated steel plate using x-ray | |
| JP5324099B2 (en) | How to apply anti-friction coating to wiper blade rubber profile and control its quality | |
| EP3783450A1 (en) | Method for applying an optimized processing treatment to items in an industrial treatment line and associated system | |
| JPH04131751A (en) | Fluorescent x-ray analytical method | |
| WO2020120162A1 (en) | Method for detecting the surface condition of components, use of the method for monitoring the surface quality of components and apparatus for adjusting the surface condition of components | |
| WO2021148160A1 (en) | Method for quantitatively detecting a surface covering of a substance covering a substrate and measuring device | |
| JPH02276903A (en) | Method and device for on-line measurement of film | |
| Chawla | Cleanliness verification and defining acceptable cleanliness levels | |
| JP2011107029A (en) | Degreased degree determining device and method | |
| CN117570864A (en) | Online in-situ monitoring method for oil film thickness on surface of opaque solid substrate | |
| JP2000283914A (en) | Chromium deposit measuring method of coating type chromate treatment film | |
| JPS6186634A (en) | Method and apparatus for measuring amount of powder film on surface of metal |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |