US20020132105A1 - Laser markable micro-pore aluminum tags and method of their fabrication - Google Patents
Laser markable micro-pore aluminum tags and method of their fabrication Download PDFInfo
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- US20020132105A1 US20020132105A1 US09/811,274 US81127401A US2002132105A1 US 20020132105 A1 US20020132105 A1 US 20020132105A1 US 81127401 A US81127401 A US 81127401A US 2002132105 A1 US2002132105 A1 US 2002132105A1
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C26/00—Coating not provided for in groups C23C2/00 - C23C24/00
- C23C26/02—Coating not provided for in groups C23C2/00 - C23C24/00 applying molten material to the substrate
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D1/00—Processes for applying liquids or other fluent materials
- B05D1/40—Distributing applied liquids or other fluent materials by members moving relatively to surface
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
- B05D3/0254—After-treatment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/06—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249954—With chemically effective material or specified gas other than air, N, or carbon dioxide in void-containing component
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249955—Void-containing component partially impregnated with adjacent component
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249955—Void-containing component partially impregnated with adjacent component
- Y10T428/249956—Void-containing component is inorganic
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249967—Inorganic matrix in void-containing component
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249967—Inorganic matrix in void-containing component
- Y10T428/24997—Of metal-containing material
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249978—Voids specified as micro
Definitions
- the present invention relates to the marking of metal, e.g., for tracking and identification purposes, and more particularly to imprinted anodized aluminum metal tags which can be attached to metal workpieces, e.g., by welding.
- a variety of finished goods e.g., automobile mechanical parts, aerospace parts, etc.
- Such goods may be at or below room temperature when the marking requirement arises.
- Such goods also may be raw or partly finished and at high temperatures, say, up to 1,100° F., in the case of aluminum. Marking of these goods for identification purposes also is required.
- anodized aluminum substrate (aluminum oxide layer formed on the surface of the aluminum by anodic oxidation, J. Elec. Chem. Society , 100, (9), 411), whose surface contains micro-pores.
- Photosensitive photographic emulsions have been applied to the anodized aluminum plates so that the emulsions become entrapped in the micro-pores (see U.S. Pat. No. 3,615,553).
- the coated plates then are photographically exposed and wet developed to produce indicia.
- the aluminum oxide high points are said to surround each exposed micro-pore cavity to protect the exposed indicia.
- a drawback to such process is the need for photographic exposure to create latent indicia with subsequent wet chemical development to make the indicia visible to the human eye. Tags for on-site marking and identification purposes could not be made practically by such a technique.
- One method of preparing a micro-pore aluminum substrate to make it act as a suitable receptor for the impregnating resin is anodizing.
- aluminum stock may be anodized in a solution of oxalic acid and oxalates of alkali metals, under controlled pH, current, and temperature, so that the resulting anodized surface is hard, adherent, and is absorbent for soaking up resins and other liquids.
- electrolytic solution and anodizing process it generally should be continued for a time sufficient to yield an anodized layer of hard aluminum oxide to a minimum thickness of 0.0002 inches and preferably up to a thickness of 0.05 inches.
- the aluminum surface After the aluminum surface has been initially oxidized, it can then be subjected to one or more powerful oxidizing solutions. such as, for example, chromic acid, or solutions of alkali ferricyanides, dichromates, or chromates, which ensure that no metallic aluminum is exposed at the base of the pores prior to them being impregnated with resin. It is critical that this secondary oxidation or “sealing” step be limited only to the base of the pore and not the entire pore. Over-oxidation seals the entire pore, which results in there being little or no space (volume) for the resin to be absorbed.
- chromic acid or solutions of alkali ferricyanides, dichromates, or chromates
- the plate bearing the prepared oxidized aluminum surface then can be impregnated with an alkyl silicone resin.
- the resulting pore diameter is especially critical, because it must be at least as wide or wider than the smallest particle of resin or other liquid being absorbed. If the pores produced during anodization are too small or the resin does not wet into the cavities, the resin will not penetrate the surface of the aluminum substrate and ultimately, little or no mark indicia will be produced.
- Polymethyl-type silicone resins are preferred, because once they are properly cured, they produce permanent black markings when subjected to a focused CO 2 laser beam.
- the invention is an anodized micro-pore aluminum tag bearing indicia thereon wherein the micro-pore anodized aluminum has its micro-pores filled with the cured reside of a composition, which contains silicone resin having pendant groups selected from one or more of methyl groups or phenyl groups.
- the composition in the micro-pores was cured to a degree effective for its blackening thereof in the form of a pattern of indicia with a, e.g., CO 2 , laser beam for marking the tag with indicia as taught in U.S. Pat. No. 5,855,969.
- the aluminum tag has a surface, which bears the micro-pores, and this surface is substantially free or devoid of said composition, i.e., the composition is present substantially only in the micro-pores.
- the method for treating the surface of the anodized micro-pore aluminum tag for forming indicia thereon commences by applying the composition to the surface. Excess of the composition from the surface is removed to leave composition resident in said micro-pores. The composition in the micro-pores then is at least partially cured. A laser then can create the indicia by blackening the composition in the micro-pores.
- This removal step of the process desirably includes a first mechanical removal with a blade, i.e., squeegee.
- Organic solvent for the composition e.g., ethyl acetate
- the surface can be rinsed with additional solvent to even out anomalies in the composition in the micro-pores.
- the composition in the micro-pores then must be cured, at least partially, by heat.
- a laser can then create the indicia by blackening the composition in the micro-pores.
- Advantages of the present invention include the ability to readily laser mark aluminum stock for manufacturing tags without further development. Another advantage includes the ability for form robust indicia recalcitrant to removal by abrasion. Yet another advantage is the ability to form aluminum tags using a rugged CO 2 laser.
- FIG. 1 is a simplified cross-sectional view of an aluminum substrate having an adherent micro-pore anodized coating, shown exaggeratedly large for purposes of illustration, with the application of a composition that contains silicone resin having pendant groups selected from one or more of methyl groups or phenyl groups and being blackenable when properly cured under the influence of a laser beam;
- FIG. 2 is the substrate of FIG. 1 showing excess composition being removed by a squeegee to leave the composition resident in the micropores of the anodized layer;
- FIG. 3 is the substrate of FIG. 2 with the composition resident in the micropores being dried (i.e., at least party cured);
- FIG. 4 is the substrate of FIG. 3 being marked by a laser marking system
- FIG. 5 is on overhead plan view of the substrate of FIG. 3 showing the resulting indicia created by the laser marking system.
- the anodized micro-pore aluminum stock is described in the references set forth above. Rather than relying on conventional wet developing techniques typical of the photography or lithography industry for forming indicia on such stock, the present invention relies on a “dry”, i.e., non-wet, technique.
- the inventive Al tags are to be used for tracking and identification purposes. Such purposes can range from raw and/or partly prepared goods to finished goods. Regardless of the state of manufacture of the goods to be marked with the inventive tags, the present invention enables aluminum tags to be manufactured for use in identification and/or tracking of such goods.
- the inventive tags are destined for tracking and/or identification purposes, they often are subject to rough and physical handling. This means that the indicia on the tags likewise needs to be rugged so that the indicia is not abraded, scraped away, or otherwise removed/obliterated with consequent loss of the information, such as is illustrated in FIG. 5.
- identification includes information, decoration, and any other purpose for which an indicia is placed upon a product in its raw, partially prepared, or final state.
- “indicia” marked on the tags includes alphanumeric symbols, 32 , graphical symbols, 34 , and the like.
- Such indicia may contain the chemistry or other information about the goods being identified, may contain a serial number to track the goods, or may contain a corporate logotype and trademark to advertise/identify the goods. Bar codes, 30 , are included within such indicia as a coding means for the goods being marked.
- the inventive marking scheme requires a composition, which is darkenable (e.g., blackened) by the focused CO 2 or other laser energy. Because many of the applications of this technology will involve the imaging of bar codes (red light absorptive or “black” bars on a white background), the composition should be highly reflective to the red light commonly used to scan such bar codes. White or red coatings, then, are preferred. For human readable characters, white backgrounds are preferred.
- the coatings of choice are silicone resin coatings, such as described in “Silicone Resin Emulsions for High-Temperature Coatings”, Modern Paint and Coatings , September 1993, Argus, Inc., Atlanta, Ga. (1993).
- Silicone resin binders typically are heat-cured in the presence of catalysts with typical catalysts being selected from acids, bases, and the salts of metals, for example, zinc, tin, lead, or chromium octoates. Silicone resins can be blended or chemically combined with other film-forming polymers provided that the ultimate cured phenyl-substituted silicone binder is stable at the hot metal temperatures of use of the inventive labels.
- Phenyl-substituted resins are well known in the art, such as represented by D. H. Solomon, The Chemistry of Organic Film Formers , Second Edition, Robert E. Krieger Publishing, Inc., pp 334 et seq. (1977). The disclosures of the cited references are expressly incorporated herein by reference.
- the composition first is applied to a surface of the anodized micro-pore aluminum stock.
- application by spraying is preferred.
- the composition could be applied by brushing, roller coating, reverse roller coating, doctor knife, coating curtain, dipping, or by any other coating technique.
- FIG. 1 depicts an aluminum substrate, 10 , having an anodized layer, 12 , adherent thereto.
- the size of the micropores has been exaggerated in order to illustrate the invention.
- a composition, 14 is seen being applied as a spray pattern, 16 , from a spray gun, 18 , which draws the composition via a hose, 20 , from a tank of the composition (not shown).
- This removal step of the process desirably includes a first mechanical removal with a blade, i.e., squeegee, 22 , as shown in FIG. 2.
- organic solvent for the composition e.g., ethyl acetate
- the surface can be rinsed with additional solvent to even out anomalies in the composition in the micro-pores.
- the last step is to at least partially cure the composition.
- This step can involve the simple flashing of solvent from the micro-pores to heat curing of the resin in the composition.
- FIG. 3 illustrates a heater, 15 , radiating heat to evaporate solvent from he composition 14 in the micropores. Curing of the composition most often is accomplished by baking in an oven, e.g., set at about 300° F., for a time ranging, e.g., from about 3 to 5 minutes. After curing, the tag can be handled for storage, shipping, or the like, prior to use. The tag also is not light sensitive.
- the tag now is ready to be marked by the energy of a focused laser beam, 24 , emitted from a CO 2 laser, 26 , as shown in FIG. 4, wherein blackened composition in the micropores, 17 , is seen.
- a CO 2 laser is preferred for its cost effectiveness and ruggedness in industrial environments. Other lasers, however, can be used at the expense of cost and risk of eye damage in industrial environments. Marking of the tag preferably is accomplished in accordance with the raster-scanning technique disclosed in U.S. Pat. No. 5,855,969.
- the tags move in the x-axis direction past a raster-scanning infrared laser beam emitting CO 2 laser that raster-scans in the Y-axis for forming the indicia on the tags.
- Scanning the laser beam through the use of two galvanometers (so-called X/Y scanning) and a flat field focusing lens also is a preferred marking method.
- a tag treated and marked in accordance with the precepts of the present invention, 28 may contain a bar code, 30 , alphanumeric characters, 32 , or a graphic, 34 , as illustrated in FIG. 5.
- Such tag may be affixed to a product by a wide variety of conventional and unconventional manners, including, for example, wiring through a hole, adhesive backings, and various fasteners.
- the tag may be affixed in the bare-area(s) welding technique disclosed in U.S. Pat. Nos. 5,422,167 and 5,484,099, by the welding pre-form technique in U.S. Pat. No. 5,714,234, or by the folded end(s) welding technique in U.S. Pat. No.
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Abstract
Description
- Not applicable.
- Not applicable.
- The present invention relates to the marking of metal, e.g., for tracking and identification purposes, and more particularly to imprinted anodized aluminum metal tags which can be attached to metal workpieces, e.g., by welding.
- A variety of finished goods (e.g., automobile mechanical parts, aerospace parts, etc.) require marking for identification purposes. Such goods may be at or below room temperature when the marking requirement arises. Such goods also may be raw or partly finished and at high temperatures, say, up to 1,100° F., in the case of aluminum. Marking of these goods for identification purposes also is required.
- In the case of aluminum goods or aluminum tags for attachment to raw, partly finished, and finished goods, the marking of aluminum presents a particularly difficult task because conventional coatings are vulnerable to abrasion. Abrasion resistance of coatings on aluminum relies on the strength of the bond of the coating to the aluminum substrate. Examples of coatings that suffer from good abrasion resistance can be found in U.S. Pat. Nos. 4,873,298 (polysiloxane graft copolymers) and U.S. Pat. No. 3,975,197 (lithographic aluminum plates with a coating of particulate material bound by an aluminum hydroxyoxide coating).
- The rapid oxidation of aluminum also creates many problems in obtaining proper adhesion levels of coatings on aluminum substrates. Methods of preparing the surface of aluminum substrates, such as by oxidizing, has been proposed in U.S. Pat. No. 3,664,888. Still, the coated aluminum surface may be compromised even by abrasion testing, for example, with a Taber Abraser. Taber abrasion resistance measures the resistance of a coating applied to a surface, such as metal, to abrasion. The coated surface is subjected to abrasion by rotating the coated panel against weighted abrasive wheels.
- In the lithography photographic plate art, there exists an anodized aluminum substrate (aluminum oxide layer formed on the surface of the aluminum by anodic oxidation,J. Elec. Chem. Society, 100, (9), 411), whose surface contains micro-pores. Photosensitive photographic emulsions have been applied to the anodized aluminum plates so that the emulsions become entrapped in the micro-pores (see U.S. Pat. No. 3,615,553). The coated plates then are photographically exposed and wet developed to produce indicia. The aluminum oxide high points are said to surround each exposed micro-pore cavity to protect the exposed indicia. A drawback to such process is the need for photographic exposure to create latent indicia with subsequent wet chemical development to make the indicia visible to the human eye. Tags for on-site marking and identification purposes could not be made practically by such a technique.
- One method of preparing a micro-pore aluminum substrate to make it act as a suitable receptor for the impregnating resin is anodizing. Thus, for example, aluminum stock may be anodized in a solution of oxalic acid and oxalates of alkali metals, under controlled pH, current, and temperature, so that the resulting anodized surface is hard, adherent, and is absorbent for soaking up resins and other liquids. Whatever electrolytic solution and anodizing process is used, it generally should be continued for a time sufficient to yield an anodized layer of hard aluminum oxide to a minimum thickness of 0.0002 inches and preferably up to a thickness of 0.05 inches. After the aluminum surface has been initially oxidized, it can then be subjected to one or more powerful oxidizing solutions. such as, for example, chromic acid, or solutions of alkali ferricyanides, dichromates, or chromates, which ensure that no metallic aluminum is exposed at the base of the pores prior to them being impregnated with resin. It is critical that this secondary oxidation or “sealing” step be limited only to the base of the pore and not the entire pore. Over-oxidation seals the entire pore, which results in there being little or no space (volume) for the resin to be absorbed.
- After washing and drying this double-oxidized surface, the plate bearing the prepared oxidized aluminum surface then can be impregnated with an alkyl silicone resin. The resulting pore diameter is especially critical, because it must be at least as wide or wider than the smallest particle of resin or other liquid being absorbed. If the pores produced during anodization are too small or the resin does not wet into the cavities, the resin will not penetrate the surface of the aluminum substrate and ultimately, little or no mark indicia will be produced. Polymethyl-type silicone resins are preferred, because once they are properly cured, they produce permanent black markings when subjected to a focused CO2 laser beam. To improve abrasion resistance of the laser marked indicia, excess resin must be removed from the surface of the anodized aluminum before curing, so that the resin, and thus, the marked indicia are only contained within the pores where they are protected by the hard outer layer of aluminum oxide formed during anodization.
- The invention, then, is an anodized micro-pore aluminum tag bearing indicia thereon wherein the micro-pore anodized aluminum has its micro-pores filled with the cured reside of a composition, which contains silicone resin having pendant groups selected from one or more of methyl groups or phenyl groups. The composition in the micro-pores was cured to a degree effective for its blackening thereof in the form of a pattern of indicia with a, e.g., CO2, laser beam for marking the tag with indicia as taught in U.S. Pat. No. 5,855,969. The aluminum tag has a surface, which bears the micro-pores, and this surface is substantially free or devoid of said composition, i.e., the composition is present substantially only in the micro-pores.
- The method for treating the surface of the anodized micro-pore aluminum tag for forming indicia thereon commences by applying the composition to the surface. Excess of the composition from the surface is removed to leave composition resident in said micro-pores. The composition in the micro-pores then is at least partially cured. A laser then can create the indicia by blackening the composition in the micro-pores.
- This removal step of the process desirably includes a first mechanical removal with a blade, i.e., squeegee. Organic solvent for the composition (e.g., ethyl acetate) then can be poured onto the surface and a pool of the solvent squeegeed across the surface to remove the composition from the surface leaving the micro-pores filled with the composition. As a second step, the surface can be rinsed with additional solvent to even out anomalies in the composition in the micro-pores. The composition in the micro-pores then must be cured, at least partially, by heat. A laser can then create the indicia by blackening the composition in the micro-pores.
- Advantages of the present invention include the ability to readily laser mark aluminum stock for manufacturing tags without further development. Another advantage includes the ability for form robust indicia recalcitrant to removal by abrasion. Yet another advantage is the ability to form aluminum tags using a rugged CO2 laser. These and other advantages will be readily apparent to those skilled in the art based upon the disclosure set forth herein.
- For a fuller understanding of the nature and advantages of the present invention, reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:
- FIG. 1 is a simplified cross-sectional view of an aluminum substrate having an adherent micro-pore anodized coating, shown exaggeratedly large for purposes of illustration, with the application of a composition that contains silicone resin having pendant groups selected from one or more of methyl groups or phenyl groups and being blackenable when properly cured under the influence of a laser beam;
- FIG. 2 is the substrate of FIG. 1 showing excess composition being removed by a squeegee to leave the composition resident in the micropores of the anodized layer;
- FIG. 3 is the substrate of FIG. 2 with the composition resident in the micropores being dried (i.e., at least party cured);
- FIG. 4 is the substrate of FIG. 3 being marked by a laser marking system; and
- FIG. 5 is on overhead plan view of the substrate of FIG. 3 showing the resulting indicia created by the laser marking system.
- The drawings will be described in further detail below.
- The anodized micro-pore aluminum stock is described in the references set forth above. Rather than relying on conventional wet developing techniques typical of the photography or lithography industry for forming indicia on such stock, the present invention relies on a “dry”, i.e., non-wet, technique. In this regard, the inventive Al tags are to be used for tracking and identification purposes. Such purposes can range from raw and/or partly prepared goods to finished goods. Regardless of the state of manufacture of the goods to be marked with the inventive tags, the present invention enables aluminum tags to be manufactured for use in identification and/or tracking of such goods.
- Also, because the inventive tags are destined for tracking and/or identification purposes, they often are subject to rough and physical handling. This means that the indicia on the tags likewise needs to be rugged so that the indicia is not abraded, scraped away, or otherwise removed/obliterated with consequent loss of the information, such as is illustrated in FIG. 5. For present purposes, “identification” includes information, decoration, and any other purpose for which an indicia is placed upon a product in its raw, partially prepared, or final state. In this regard, “indicia” marked on the tags includes alphanumeric symbols,32, graphical symbols, 34, and the like. Such indicia may contain the chemistry or other information about the goods being identified, may contain a serial number to track the goods, or may contain a corporate logotype and trademark to advertise/identify the goods. Bar codes, 30, are included within such indicia as a coding means for the goods being marked.
- The inventive marking scheme requires a composition, which is darkenable (e.g., blackened) by the focused CO2 or other laser energy. Because many of the applications of this technology will involve the imaging of bar codes (red light absorptive or “black” bars on a white background), the composition should be highly reflective to the red light commonly used to scan such bar codes. White or red coatings, then, are preferred. For human readable characters, white backgrounds are preferred.
- The coatings of choice are silicone resin coatings, such as described in “Silicone Resin Emulsions for High-Temperature Coatings”,Modern Paint and Coatings, September 1993, Argus, Inc., Atlanta, Ga. (1993). Silicone resin binders typically are heat-cured in the presence of catalysts with typical catalysts being selected from acids, bases, and the salts of metals, for example, zinc, tin, lead, or chromium octoates. Silicone resins can be blended or chemically combined with other film-forming polymers provided that the ultimate cured phenyl-substituted silicone binder is stable at the hot metal temperatures of use of the inventive labels. Phenyl-substituted resins are well known in the art, such as represented by D. H. Solomon, The Chemistry of Organic Film Formers, Second Edition, Robert E. Krieger Publishing, Inc., pp 334 et seq. (1977). The disclosures of the cited references are expressly incorporated herein by reference.
- In order to create ruggedly marked tags, the composition first is applied to a surface of the anodized micro-pore aluminum stock. In order to obtain an even coat of the composition, application by spraying (atomization) is preferred. Alternatively, the composition could be applied by brushing, roller coating, reverse roller coating, doctor knife, coating curtain, dipping, or by any other coating technique. Such step of the process is illustrated in FIG. 1, which depicts an aluminum substrate,10, having an anodized layer, 12, adherent thereto. The size of the micropores has been exaggerated in order to illustrate the invention. A composition, 14, is seen being applied as a spray pattern, 16, from a spray gun, 18, which draws the composition via a hose, 20, from a tank of the composition (not shown).
- Next, excess applied composition is removed from the surface to leave said composition resident in said micro-pores. This removal step of the process desirably includes a first mechanical removal with a blade, i.e., squeegee,22, as shown in FIG. 2. As an optional second removal step, organic solvent for the composition (e.g., ethyl acetate) can be poured onto the surface and a pool of the solvent squeegeed across the surface to remove the composition from the surface leaving the micropores filled with the composition. As an optional third step, the surface can be rinsed with additional solvent to even out anomalies in the composition in the micro-pores.
- The last step is to at least partially cure the composition. This step can involve the simple flashing of solvent from the micro-pores to heat curing of the resin in the composition. FIG. 3 illustrates a heater,15, radiating heat to evaporate solvent from he
composition 14 in the micropores. Curing of the composition most often is accomplished by baking in an oven, e.g., set at about 300° F., for a time ranging, e.g., from about 3 to 5 minutes. After curing, the tag can be handled for storage, shipping, or the like, prior to use. The tag also is not light sensitive. - The tag now is ready to be marked by the energy of a focused laser beam,24, emitted from a CO2 laser, 26, as shown in FIG. 4, wherein blackened composition in the micropores, 17, is seen. A CO2 laser is preferred for its cost effectiveness and ruggedness in industrial environments. Other lasers, however, can be used at the expense of cost and risk of eye damage in industrial environments. Marking of the tag preferably is accomplished in accordance with the raster-scanning technique disclosed in U.S. Pat. No. 5,855,969. In accordance with this technique, the tags move in the x-axis direction past a raster-scanning infrared laser beam emitting CO2 laser that raster-scans in the Y-axis for forming the indicia on the tags. Scanning the laser beam through the use of two galvanometers (so-called X/Y scanning) and a flat field focusing lens also is a preferred marking method.
- A tag treated and marked in accordance with the precepts of the present invention,28, may contain a bar code, 30, alphanumeric characters, 32, or a graphic, 34, as illustrated in FIG. 5. Such tag may be affixed to a product by a wide variety of conventional and unconventional manners, including, for example, wiring through a hole, adhesive backings, and various fasteners. The tag may be affixed in the bare-area(s) welding technique disclosed in U.S. Pat. Nos. 5,422,167 and 5,484,099, by the welding pre-form technique in U.S. Pat. No. 5,714,234, or by the folded end(s) welding technique in U.S. Pat. No. 6,063,458, the disclosures of which are expressly incorporated herein by reference. In this regard, only one edge of the laser marked tag may be welded to the product leaving the opposite end free. This configuration may permit the tag to be lifted and cracked off adjacent the weld attachment. In fact, the laser marked tag even may be scored to facilitate this crack off procedure of removing the tag once its function of product identification has been satisfied.
- While the invention has been described with reference to a preferred embodiment, those skilled in the art will understand that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. In this application all units are in the metric system and all amounts and percentages are by weight, unless otherwise expressly indicated. Also, all citations referred herein are expressly incorporated herein by reference.
Claims (13)
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/811,274 US6451421B1 (en) | 2001-03-19 | 2001-03-19 | Laser markable micro-pore aluminum tags and method of their fabrication |
PCT/US2002/003212 WO2002083405A1 (en) | 2001-03-19 | 2002-02-04 | Laser markable micro-pore aluminum tags and method of their fabrication |
EP02702139A EP1453667A4 (en) | 2001-03-19 | 2002-02-04 | Laser markable micro-pore aluminum tags and method of their fabrication |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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US09/811,274 US6451421B1 (en) | 2001-03-19 | 2001-03-19 | Laser markable micro-pore aluminum tags and method of their fabrication |
Publications (2)
Publication Number | Publication Date |
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US6451421B1 US6451421B1 (en) | 2002-09-17 |
US20020132105A1 true US20020132105A1 (en) | 2002-09-19 |
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Application Number | Title | Priority Date | Filing Date |
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US09/811,274 Expired - Lifetime US6451421B1 (en) | 2001-03-19 | 2001-03-19 | Laser markable micro-pore aluminum tags and method of their fabrication |
Country Status (3)
Country | Link |
---|---|
US (1) | US6451421B1 (en) |
EP (1) | EP1453667A4 (en) |
WO (1) | WO2002083405A1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
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US20070092739A1 (en) * | 2005-10-25 | 2007-04-26 | Steele Leslie S | Treated Aluminum article and method for making same |
US20140193607A1 (en) * | 2012-06-22 | 2014-07-10 | Apple Inc. | White appearing anodized films and methods for forming the same |
US9493876B2 (en) | 2012-09-14 | 2016-11-15 | Apple Inc. | Changing colors of materials |
US9839974B2 (en) | 2013-11-13 | 2017-12-12 | Apple Inc. | Forming white metal oxide films by oxide structure modification or subsurface cracking |
US10017872B2 (en) | 2013-10-30 | 2018-07-10 | Apple Inc. | Metal oxide films with reflective particles |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
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DE60036078T2 (en) | 1999-11-11 | 2008-05-15 | Koninklijke Philips Electronics N.V. | MARKING AN ANODIZED LAYER OF AN ALUMINUM OBJECT |
US6717102B2 (en) * | 2000-06-08 | 2004-04-06 | Joseph Neev | Laser tissue processing for cosmetic and bio-medical applications |
US6835457B2 (en) * | 2001-05-15 | 2004-12-28 | Markem Corporation | Marking substrates |
GB0127410D0 (en) | 2001-11-15 | 2002-01-09 | Renishaw Plc | Laser substrate treatment |
GB0201101D0 (en) * | 2002-01-18 | 2002-03-06 | Renishaw Plc | Laser marking |
US6764016B2 (en) * | 2002-10-17 | 2004-07-20 | Infosight Corporation | Identification method for dip galvanizing |
US6821305B2 (en) * | 2003-04-01 | 2004-11-23 | Jas. D. Easton, Inc. | Process of producing a colored area of desired depth in an anodized layer of metal article |
WO2007138647A1 (en) * | 2006-05-25 | 2007-12-06 | Mitsubishi Electric Corporation | Stator of dynamo-electric machine |
US10787753B2 (en) | 2016-09-14 | 2020-09-29 | Apple Inc. | Anodized substrates with dark laser markings |
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US3664888A (en) * | 1965-10-09 | 1972-05-23 | Sumitomo Electric Industries | Method of resin coating a metal and resin-coated metal product thereof |
US3615553A (en) * | 1970-05-06 | 1971-10-26 | Horizons Research Inc | Aluminum photographic surfaces |
US3975197A (en) * | 1973-02-12 | 1976-08-17 | Minnesota Mining And Manufacturing Company | Coated aluminum substrates |
US4873298A (en) * | 1986-12-16 | 1989-10-10 | E. I. Du Pont De Nemours And Company | Polysiloxane graft copolymers, flexible coating compositions comprising same and branched polysiloxane macromers for preparing same II |
US4833306A (en) * | 1988-05-18 | 1989-05-23 | Fluoroware, Inc. | Bar code remote recognition system for process carriers of wafer disks |
US5422167A (en) * | 1993-09-17 | 1995-06-06 | Infosight Corporation | High temperature-resistant, thermally-printable label for attachment to hot metal stock and method thereof |
JPH07204871A (en) * | 1994-01-20 | 1995-08-08 | Fuji Electric Co Ltd | Marking method |
US6001481A (en) * | 1995-03-08 | 1999-12-14 | Southwest Research Institute | Porous anodized aluminum surfaces sealed with diamond-like carbon coatings |
US5855969A (en) * | 1996-06-10 | 1999-01-05 | Infosight Corp. | CO2 laser marking of coated surfaces for product identification |
US5714234A (en) * | 1996-06-10 | 1998-02-03 | Infosight Corporation | Identification tag with preform attachment |
US6063458A (en) * | 1999-02-11 | 2000-05-16 | Infosight Corporation | Folded identification tags |
-
2001
- 2001-03-19 US US09/811,274 patent/US6451421B1/en not_active Expired - Lifetime
-
2002
- 2002-02-04 WO PCT/US2002/003212 patent/WO2002083405A1/en not_active Application Discontinuation
- 2002-02-04 EP EP02702139A patent/EP1453667A4/en not_active Withdrawn
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070092739A1 (en) * | 2005-10-25 | 2007-04-26 | Steele Leslie S | Treated Aluminum article and method for making same |
US7527872B2 (en) * | 2005-10-25 | 2009-05-05 | Goodrich Corporation | Treated aluminum article and method for making same |
US20140193607A1 (en) * | 2012-06-22 | 2014-07-10 | Apple Inc. | White appearing anodized films and methods for forming the same |
US8993921B2 (en) * | 2012-06-22 | 2015-03-31 | Apple Inc. | Method of forming white appearing anodized films by laser beam treatment |
US10184190B2 (en) | 2012-06-22 | 2019-01-22 | Apple Inc. | White appearing anodized films |
US10941503B2 (en) | 2012-06-22 | 2021-03-09 | Apple Inc. | White appearing anodized films |
US9493876B2 (en) | 2012-09-14 | 2016-11-15 | Apple Inc. | Changing colors of materials |
US10017872B2 (en) | 2013-10-30 | 2018-07-10 | Apple Inc. | Metal oxide films with reflective particles |
US9839974B2 (en) | 2013-11-13 | 2017-12-12 | Apple Inc. | Forming white metal oxide films by oxide structure modification or subsurface cracking |
US10434602B2 (en) | 2013-11-13 | 2019-10-08 | Apple Inc. | Forming white metal oxide films by oxide structure modification or subsurface cracking |
Also Published As
Publication number | Publication date |
---|---|
WO2002083405A1 (en) | 2002-10-24 |
US6451421B1 (en) | 2002-09-17 |
EP1453667A1 (en) | 2004-09-08 |
EP1453667A4 (en) | 2007-10-31 |
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