EP2683520A1 - Method and apparatus for reliably laser marking articles - Google Patents
Method and apparatus for reliably laser marking articlesInfo
- Publication number
- EP2683520A1 EP2683520A1 EP11860649.0A EP11860649A EP2683520A1 EP 2683520 A1 EP2683520 A1 EP 2683520A1 EP 11860649 A EP11860649 A EP 11860649A EP 2683520 A1 EP2683520 A1 EP 2683520A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- laser
- pulse
- anodized aluminum
- pulses
- marks
- 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.)
- Withdrawn
Links
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/04—Automatically aligning, aiming or focusing the laser beam, e.g. using the back-scattered light
- B23K26/046—Automatically focusing the laser beam
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
- B23K26/062—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam
- B23K26/0622—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/08—Devices involving relative movement between laser beam and workpiece
- B23K26/082—Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/08—Devices involving relative movement between laser beam and workpiece
- B23K26/083—Devices involving movement of the workpiece in at least one axial direction
- B23K26/0853—Devices involving movement of the workpiece in at least in two axial directions, e.g. in a plane
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/18—Working by laser beam, e.g. welding, cutting or boring using absorbing layers on the workpiece, e.g. for marking or protecting purposes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/36—Removing material
- B23K26/362—Laser etching
- B23K26/364—Laser etching for making a groove or trench, e.g. for scribing a break initiation groove
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/36—Removing material
- B23K26/40—Removing material taking account of the properties of the material involved
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2101/00—Articles made by soldering, welding or cutting
- B23K2101/34—Coated articles, e.g. plated or painted; Surface treated articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2101/00—Articles made by soldering, welding or cutting
- B23K2101/34—Coated articles, e.g. plated or painted; Surface treated articles
- B23K2101/35—Surface treated articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2103/00—Materials to be soldered, welded or cut
- B23K2103/08—Non-ferrous metals or alloys
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2103/00—Materials to be soldered, welded or cut
- B23K2103/08—Non-ferrous metals or alloys
- B23K2103/10—Aluminium or alloys thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2103/00—Materials to be soldered, welded or cut
- B23K2103/16—Composite materials, e.g. fibre reinforced
Definitions
- the present invention relates to laser marking of anodized aluminum articles.
- marking anodized aluminum with a laser processing system.
- marking anodized aluminum in a durable and commercially desirable fashion with a laser processing system.
- characterizing the interaction between visible and infrared wavelength picosecond laser pulses and the anodized aluminum to reliably and repeatably create durable marks with a desired color and optical density.
- Desirable attributes for marking include consistent appearance, durability, and ease of application. Appearance refers to the ability to reliably and repeatably render a mark with a selected shape, color and optical density. Durability is the quality of remaining unchanged in spite of abrasion to the marked surface. Ease of application refers to the cost in materials, time and resources of producing a mark including programmability. Programmability refers to the ability to program the marking device with a new pattern to be marked by changing software as opposed to changing hardware such as screens or masks.
- Anodized aluminum which is lightweight, strong, easily shaped, and has a durable surface finish, has many applications in industrial and
- Anodization describes any one of a number of electrolytic passivation processes in which a natural oxide layer is increased on metals such as aluminum, titanium, zinc, magnesium, niobium or tantalum in order to increase resistance to corrosion or wear and for cosmetic purposes.
- metals such as aluminum, titanium, zinc, magnesium, niobium or tantalum in order to increase resistance to corrosion or wear and for cosmetic purposes.
- These surface layers can be colored or dyed virtually any color, making a
- Anodized aluminum is an exemplary material that has such needs. Marking anodized aluminum with laser pulses produced by a laser processing system can make durable marks quickly at extremely low cost per mark in a programmable fashion.
- LIPSS laser-induced periodic surface structures
- LIPSS is the only explanation offered for the creation of marks on metallic surfaces. Further, only laser pulses having temporal pulse widths of 65 femtoseconds are taught or suggested to create these structures. In addition, no mention is made as to whether the aluminum samples are anodized or have had the surface cleaned prior to laser processing. Further the article does not discuss possible damage to the oxide layer. [0006] When discussing laser pulse duration, the method of measuring pulse duration should be defined. Temporal pulse shape can range from simple Gaussian pulses to more complex shapes depending upon the task.
- non-Gaussian laser pulses advantageous for certain types of processing are described in US patent no. 7,126,746 GENERATING SETS OF TAILORED LASER PULSES, Sun et al inventors, which patent has been assigned to the assignees of the instant invention and is hereby incorporated by reference.
- This patent discloses methods and apparatus to create laser pulses with temporal profiles that vary from the typical Gaussian temporal profiles produced by diode pumped solid state (DPSS) lasers.
- DPSS diode pumped solid state
- These non- Gaussian pluses are called “tailored" pulses because their temporal profile is altered from the typical Gaussian profile by combining more than one pulse to create a single pulse and/or modulating the pulse electro-optically.
- This type of tailored pulse can be effective in processing materials at high rates without causing problems with debris or excessive heating of surrounding material.
- An issue is that measuring the duration of complex pulses such as these using standard methods typically applied to Gaussian pulses can yield anomalous results.
- Gaussian pulse durations are typically measured using the full width at half maximum (FWHM) measure of duration.
- T(t) is a function which represents the temporal shape of the laser pulse.
- Making marks according to the methods claimed in this patent are disadvantageous for two reasons: first, creating commercially desirable black marks with nanosecond-range pulses tends to cause destruction of the oxide layer and secondly, cleaning of the aluminum following polishing or other processing adds another step in the process, with associated expense, and possibly disturbs a desired surface finish by further processing.
- An aspect of this invention is to mark anodized aluminum articles with visible marks of various optical densities or grayscale and colors. These marks should be durable and have commercially desirable appearance. This is achieved by using picosecond laser pulses to create the marks. These marks are created at the surface of the aluminum underneath the oxide layer and are therefore protected by the oxide. The picosecond laser pulses create commercially desirable marks without causing significant damage to the oxide layer, thereby making the marks durable. Durable, commercially desirable marks are created on anodized aluminum by controlling the laser parameters with which create and direct picosecond laser pulses.
- a laser processing system is adapted to produce laser pulses with appropriate parameters in a programmable fashion.
- Exemplary laser pulse parameters which may be selected to improve the reliability and repeatability of laser marking anodized aluminum include laser type, wavelength, pulse duration, pulse repletion rate, number of pulses, pulse energy, pulse temporal shape, pulse spatial shape and focal spot size and shape. Additional laser pulse parameters include specifying the location of the focal spot relative to the surface of the article and directing the relative motion of the laser pulses with respect to the article.
- aspects of this invention create durable, commercially desirable marks by darkening the surface of the aluminum beneath the anodization with optical densities which range from nearly undetectable with the unaided eye to black depending upon the particular laser pulse parameters employed.
- Other aspects of this invention create colors in various optical densities in shades of tan or gold, likewise depending upon the particular laser pulse parameters employed.
- Other aspects of this invention create durable, commercially desirable marks on anodized aluminum by bleaching or partially bleaching dyed or colored anodization with or without marking the aluminum beneath.
- a method for creating a color and optical density selectable visible mark on an anodized aluminum specimen and apparatus adapted to perform the method is disclosed herein.
- the invention is a method and apparatus for creating a color and optical density selectable visible mark on an anodized aluminum specimen.
- the method includes providing a laser marking system having a laser, laser optics and a controller operatively connected to said laser to control laser pulse parameters and a controller with stored laser pulse parameters, selecting the stored laser pulse parameters associated with the desired color and optical density, directing the laser marking system to produce laser pulses having laser pulse parameters associated with the desired color and optical density including temporal pulse widths greater than about 1 and less than about 1000 picoseconds to impinge upon said anodized aluminum.
- a goal of this invention is to mark anodized aluminum articles with visible marks of various optical densities and colors, durably, selectably, predictably, and repeatably. It is advantageous for these marks to appear on or near the surface of the aluminum and leave the anodization layer substantially intact to protect both the surface and the marks. Marks made in this fashion are referred to as interlayer marks since they are made at or on the surface of the aluminum beneath the oxide layer that forms the
- the oxide remains intact following marking in order to protect the marks and provide a surface that is mechanically contiguous between adjacent marked and non-marked regions.
- these marks should be able to be produced reliably and repeatably, meaning that if a mark with a specific color and optical density is desired, a set of laser parameters is known which will produce the desired result when the anodized aluminum is processed by a laser processing system. It is also contemplated that such marks created with a laser processing system be invisible. In this aspect, the laser processing system creates marks which are not visible under ordinary viewing conditions, but which become visible under other conditions, for example when illuminated by ultraviolet light. It is contemplated that these marks be used to provide anti-theft marking or other special marks.
- An embodiment of the instant invention uses an adapted laser processing system to mark anodized aluminum articles.
- An exemplary laser processing system which can be adapted to mark anodized aluminum articles is the ESI MM5330 micromachining system, manufactured by Electro
- micromachining system employing a diode-pumped Q-switched solid state laser with an average power of 5.7 W at 30 K Hz pulse repetition rate, second harmonic doubled to 532 nm wavelength.
- Another exemplary laser processing system which may be adapted to mark anodized aluminum articles is the ESI ML5900 micromachining system, also manufactured by Electro Scientific Industries, Inc., Portland, OR 97229. This system employs a solid state diode-pumped laser which can be configured to emit wavelengths from about 355 nm (UV) to about 1064 nm (IR) at pulse repetition rates up to 5 MHz.
- Either system may be adapted by the addition of appropriate laser, laser optics, parts handling equipment and control software to reliably and repeatably produce marks in anodized aluminum surfaces according to the methods disclosed herein.) These modifications permit the laser processing system to direct laser pulses with the appropriate laser parameters to the desired places on an appropriately positioned and held anodized aluminum article at the desired rate and pitch to create the desired mark with desired color and optical density.
- a diagram of such an adapted system is shown in Fig 1 .
- Fig 1 shows a diagram of an ESI MM5330 micromachining system adapted for marking articles according to an embodiment of the instant invention.
- Adaptations include the laser 10, which, in an embodiment of this invention is a diode pumped Nd:YVO 4 solid state laser operating at 1064 nm wavelength, model Rapid manufactured by Lumera laser GmbH,
- This laser is optionally frequency doubled using a solid state harmonic frequency generator to reduce the wavelength to 532 nm or tripled to about 355 nm, thereby creating visible (green) or ultraviolet (UV) laser pulses, respectively.
- This laser 10 is rated to produce 6 Watts of continuous power and has a maximum pulse repetition rate of 1000 KHz. This laser 10 produces laser pulses 12 with duration of 1 to 1 ,000
- laser pulses 12 may be Gaussian or specially shaped or tailored by the laser optics 14 to permit desired marking.
- the laser optics 14, in cooperation with the controller 20, direct laser pulses 12 to form a laser spot 16 on or near article 18.
- Article 18 is fixtured upon stage 22, which includes motion control elements which, in cooperation with the controller 20 and laser optics 14 provides compound beam positioning capability.
- Compound beam positioning is the capability to mark shapes on an article 18 while the article 18 is in relative motion to the laser spot 16 by having the controller 20 direct steering elements in the laser optics 14 to compensate for the relative motion induced by motion of the stage 22, the laser spot 16 or both.
- the laser pulses 12 are also shaped by the laser optics 14 in
- the laser optics 14 directs the laser pulses' 12 spatial shape, which may be Gaussian or specially shaped. For example, a "top hat" spatial profile may be used which delivers a laser pulse 12 having an even dose of radiation over the entire spot which impinges the article being marked. Specially shaped spatial profiles such as this may be created using diffractive optical elements. Laser pulses 12 also may be shuttered or directed by electro-optical elements, steerable mirror elements or galvanometer elements of the laser optics 14.
- the laser spot 16 refers to the focal spot of the laser beam formed by the laser pulses 12.
- the distribution of laser energy at the laser spot 12 depends upon the laser optics 14.
- the laser optics 14 control the depth of focus of the laser spot 12, or how quickly the spot goes out of focus as the plane of measurement moves away from the focal plane.
- the controller 20 can direct the laser optics 14 and the stage 22 to position the laser spot 16 either at or near the surface of the article 18 repeatably with high precision. Making marks by positioning the focal spot above or below the surface of the article allows the laser beam to defocus by a specified amount and thereby increase the area illuminated by the laser pulse and decrease the laser fluence at the surface. Since the geometry of the beam waist is known, precisely positioning the focal spot above or below the actual surface of the article will provide additional precision control over the spot size and fluence.
- Picosecond lasers which produce laser pulse widths in the range from 1 to 1 ,000 picoseconds, are the preferred lasers for reliably and repeatably creating marks on anodized aluminum.
- Fig 2 is a microphotograph showing a mark created on anodized aluminum 30 using prior art laser with >1
- Fig 3 shows the same color and optical density mark 38 on the same type of anodized aluminum 36 made with a picosecond laser showing no cracking.
- Picosecond lasers mark anodized aluminum articles with a commercially desirable black without causing damage to the oxide layer.
- Another advantage of using picosecond lasers is that they are much less expensive, require much less maintenance, and typically have much longer operating lifetimes than prior art femtosecond lasers.
- aspects of the instant invention do not require cleaning of the aluminum surface prior to anodization to create commercially desirable marks.
- An embodiment of the instant invention performs marking on anodized aluminum under the anodization.
- the laser fluence defined by:
- Laser parameters associated with a particular color or optical density can also be determined by methods other than empirical. For example, laser parameters may be determined by running computer simulations of
- laser/material interactions such as textbooks, laser manuals or other technical literature may be accessed and appropriate laser parameters determined by extrapolation therefrom.
- laser processing system By directing the laser processing system to produce laser pulses with the proper laser parameters and precisely controlling the laser fluence, marks of desired color and optical density can be reliably and repeatably created on anodized aluminum articles.
- FIG 4 shows a diagram of a laser pulse focal spot 40 and the beam waist in its vicinity.
- the beam waist is represented by a surface 42 which is the diameter of the spatial energy distribution of a laser pulse as measured by the FWHM method on the optical axis 44 along which the laser pulses travel.
- the diameter 48 represents the laser pulse spot size on the surface of the aluminum when the laser processing system focuses the laser pulse at a distance (A-O) above the surface.
- Diameter 46 represents the laser pulse spot size on the surface of the aluminum when the laser processing system focuses the laser pulses at a distance (O-B) below the surface.
- FIGs 5 and 6 show a series of grayscale marks made on anodized aluminum made by an embodiment of this invention. The optical density of the marks range from nearly
- each grayscale mark can be identified by a unique triplet of CIE colorimetry values. L * , a * and b * .
- An aspect of the instant invention associates each desired grayscale value with a set of laser parameters that reliably and repeatably produce the desired grayscale value mark on anodized aluminum upon command. Note also that the marks which may seem indistinguishable to the naked eye can become visible when illuminated with other than broad spectrum visible light, for example ultraviolet light.
- the marks 60, 62, 64, 66 range in optical density from virtually unnoticeable 60 against the unmarked aluminum to full black 62.
- Grayscale optical densities 64, 66 between the two extremes are created by moving the focal spot closer to the article, increasing the fluence and thereby creating darker marks.
- the height of the focal spot above the surface of the aluminum varies from zero, in the case of the darkest optical density mark 62, increasing by 500 micron increments for each mark 64, 66 from right to left in Fig 4, ending at 5 mm above the surface for the lightest mark 60.
- marks 64 created with focal spot located 4.5 to 1 .5 mm above the surface of the aluminum show tan or golden colors and marks created with focal spot one mm 62 and 66 or less appear gray or black. Maintaining this precise control over the laser focal spot distance from the work surface in addition to maintaining other laser parameters within normal laser processing tolerances permits laser marks with desired color and optical density to be made on anodized aluminum.
- Another aspect of the instant invention determines the relationship between marks with colors other than grayscale and picosecond laser pulse parameters.
- Colors other than grayscale can be produced on anodized aluminum in two different ways. In the first, a gold tone can be produced in a range of optical densities. This color is produced by changes made at the interface between the aluminum and the oxide coating. Careful choice of laser pulse parameters will produce the desired golden color without damaging the oxide coating.
- Fig 5 also shows various shades of gold or tan created by an aspect of the instant invention.
- Laser marking of anodized aluminum can also be achieved by an aspect of the instant invention which uses IR wavelength laser pulses to mark the aluminum.
- This aspect creates marks of varying grayscale densities by varying the laser fluence at the surface of the aluminum in two different manners.
- grey scale can be achieved by varying the fluence at the surface by positioning the focal spot above or below the surface of the aluminum.
- the second manner of controlling grey scale is to vary the total dose at the surface of the aluminum by changing the bite sizes or line pitches when marking the desired patterns.
- Changing bite sizes refers to adjusting the rate at which the laser pulse beam is moved relative to the surface of the aluminum or changing the pulse repetition rate or both, which results in changing the distance between successive laser pulse impact sites on the aluminum.
- Varying line pitches refers to adjusting the distance between marked lines to achieve various degrees of overlapping.
- a second type of marking which may be applied to anodized aluminum using picosecond laser pulses is alterations in color contrast caused by bleaching of dyed anodization.
- anodization On a microscopic scale, anodization is porous, and will readily accept dyes of many types. Referring again to Fig 3, this microphotograph of anodized aluminum shows the porous nature of surface.
- Laser pulses used to mark dyed anodized aluminum can, depending upon the wavelength and pulse energy, bleach the dye as it marks the aluminum, making the anodization transparent and thereby reveals the marks on the aluminum underneath. With higher fluence, simultaneous dye bleaching and marking of the aluminum beneath the anodization layer with black, grey scale, or colors presented in previous section is possible.
- Fig 7 shows a dyed anodized aluminum article with marks made with visible (532 nm) laser pulses. Note that the dye in the anodization is bleached in the areas subjected to laser pulses.
- Fig 8 shows the same type of dyed anodized aluminum article with marks made with IR (1064 nm) laser pulses. Note that the anodization is not bleached by the IR laser pulses and therefore does not reveal the aluminum color beneath beyond the translucency of the original oxide.
- Another aspect of this invention relates to laser marking anodized aluminum with colored anodization using picosecond lasers. Since
- Fig 7 shows an anodized aluminum article 80 with pink dye in the anodization and an array of marks 82 produced according to an aspect of the instant invention. Colors are created by bleaching the dye in the oxide layer as the aluminum underneath showed native (silver) color to a range of laser-marked colors from shades of tan, to gray and finally black. These shades are created by varying the fluence of the laser pulses at the surface of the aluminum.
- the four rows represent varying the pitch of the laser pulses from 10 to 50 microns and the columns represent varying the focal spot distance from the surface from 0.0 to 5.0 mm.
- These laser parameters in all cases bleach the dye in the oxide overlaying the aluminum allowing the marks on the aluminum show through.
- Fig 7 shows an anodized aluminum article 100 with pink dye with marks 102 made with IR laser pulses.
- the marks range from translucent to black and were made by altering the laser fluence by both changing the distance from the focal spot to the surface and by changing the pitch.
- the six columns represent changing the distance between the focal spot of the laser pulses and the surface of the aluminum from 5.5 mm (right) to zero (left).
- the four rows represent changing the laser pulse pitch from 10 to 50 microns.
- Laser parameters used to create these marks is shown in Table 4.
- Fig 9 The relationship between bleaching anodization dye, marking aluminum and causing surface ablation for 532 nm (green) laser wavelengths is shown in Fig 9.
- Fig 8 shows the fluence thresholds in Joules/cm 2 for bleaching anodization (Fb), marking aluminum under the anodization (Fu), and surface ablation (Fs).
- Fb 0.1 J/ cm 2
- Fu 0.13 J/ cm 2
- Fs 0.18 J/cm 2
- Fig 10 shows the fluence thresholds in
- Joules/cm 2 for 1064 nm (IR) laser pulses with parameters within those given in Tables 1 , 2, and 3.
- no threshold for bleaching anodization is available since IR wavelength laser pulses do not begin to bleach anodization until laser fluence is great enough to cause damage to the overlaying anodization.
- Fb, Fu and Fs will depend upon the particular laser and optics used. They must be determined experimentally for a given processing setup and article to be marked and stored in the controller for later use.
- the programmable nature of the adapted laser processing system permits the marking of anodized aluminum articles with commercially desirable marks in patterns.
- a pattern 1 10 is converted into a digital representation 1 12, which is decomposed into a list 1 14, where each entry 1 16 in the list 1 14 contains a representation of a location or locations, with a color and optical density associated with each location.
- the list 1 14 is stored in the controller 20.
- the controller 20 associates laser parameters with each entry 1 16 in the list 1 14, which laser parameters, when sent as commands to the laser 10, optics 14 and motion control stage 22 will cause the laser 10 to generate one or more laser pulses 12 which impinge aluminum article 18 at or near the surface 16.
- These pulses will create a mark with the desired color and optical density.
- marks of the desired range of colors and optical density are made on the anodized aluminum surface in the desired pattern.
- colored anodization is patterned over previously patterned marks to present additional colors and optical densities.
- a grayscale pattern is created on an anodized aluminum article.
- the article is then coated with a photoresist coating that can be developed by exposure to laser pulses.
- the grayscale patterned, photoresist coated article is placed into the laser processing system and aligned so that the system can apply laser pulses in registration with the pattern already applied to the article.
- the photoresist used is a type known as "negative" photoresist, where areas exposed to laser radiation will be removed and the unexposed areas will remain on the article following subsequent processing.
- This anodization layer is designed to be translucent in order to allow light to pass through the anodization to the pattern below and be reflected back through the anodization and thereby create color patterns with selected color and optical density.
- This color anodization can also be bleached if necessary using techniques disclosed by other aspects of this invention to create a desired color with desired transparency.
- This color can be applied over areas of the underlying pattern or applied on a point-by-point basis down to the limits of resolution of the laser system, typically in the 10 to 400 micron range. This operation can be repeated to create multiple color overlays.
- the anodization color overlay is applied in a multiple color overlay grid, such as Bayer pattern.
- a durable, commercially desirable full color image can be created on the anodized aluminum article.
- Figs 12a through 12i show a sequence of steps used to create this color overlay for two colors.
- an aluminum article 1 18 has a transparent anodization layer 120 and marks 122 previously applied according to other aspects of this invention.
- a negative photoresist 124 is applied to the surface of the transparent anodization 120.
- laser pulses 126 expose areas 128, 130 of the photoresist 124.
- Fig 12c the unexposed resist 134 remains following resist processing, but the exposed resist has been removed leaving voids 132 in the processed resist layer 134.
- Fig 12d shows the base anodization layer 120 with sections 136 where the anodization has been dyed with color beneath the voids 132 in the processed resist layer 134.
- Fig 12e shows the article 1 18 with base anodization 120 with color portions of anodization 136 in relation to previously applied marks 122 following removal of processed resist.
- Fig 12f shows an article 1 18 with base anodization 120 including colored portions 136 and a second resist layer 138.
- Fig 12g shows this second layer of resist 138 impinged by laser pulses 142 to cause area 140 to become exposed.
- Fig 12g shows the article 1 18 with base anodization 120 following processing to, dye the anodization beneath the removed resist 140, and removal of the remaining resist 138. This leaves the intact base anodization layer with colored areas 136, 144 over the previously marked areas 122.
- Fig 12i shows subsequent laser pulses 146 being used to optionally bleach portions of the previously anodized and dyed portions of the aluminum article to create additional desired colors or optical densites.
- the processing described by this aspect of this invention results in a colored pattern being overlaid over a grayscale pattern, yielding marks with a wide range of durable, commercially desirable colors and optical densities in patterns which are programmable.
- the color anodization may be created on the anodized aluminum article in particular patterns which yield the appearance of full color images when viewed.
- a pattern representative of an image is applied to the surface using techniques described herein.
- the color dyes are introduced in the manner illustrated in Figs 12a through 12i, except that the pattern with which these dyes are introduced into the base layer of anodization is designed to convert the grayscale representation into full color.
- a pattern is a Bayer filter (not shown), which juxtaposes red, green and blue filter elements in a pattern such that the eye perceives the red, green and blue elements fusing into a single color with optical density related to the grayscale mark underneath the color anodization filters, thereby creating the appearance of a full color image or pattern.
- the resist may be negative or positive resist, and the patterns which expose the resist may be created by masks, such as used in circuit or semiconductor applications, or directly written by a electronic means or directly deposited by technologies such as inkjet or directly ablated by laser.
Abstract
Description
Claims
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PCT/US2011/027943 WO2012121733A1 (en) | 2011-03-10 | 2011-03-10 | Method and apparatus for reliably laser marking articles |
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EP2683520A1 true EP2683520A1 (en) | 2014-01-15 |
EP2683520A4 EP2683520A4 (en) | 2016-05-11 |
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EP11860649.0A Withdrawn EP2683520A4 (en) | 2011-03-10 | 2011-03-10 | Method and apparatus for reliably laser marking articles |
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EP (1) | EP2683520A4 (en) |
JP (1) | JP2014509946A (en) |
KR (1) | KR101881621B1 (en) |
CN (1) | CN103228399B (en) |
WO (1) | WO2012121733A1 (en) |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
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US9290008B1 (en) | 2011-09-20 | 2016-03-22 | Nlight Photonics Corporation | Laser marking method and system |
RU2615381C1 (en) * | 2015-09-21 | 2017-04-04 | Владимир Ефимович Рогалин | Method for laser marking of product surface of aluminium or its alloy with oxide outer layer |
US9837784B2 (en) | 2015-12-28 | 2017-12-05 | Nlight, Inc. | Fully controllable burst shaping individual pulses from picosecond fiber lasers |
CN106529620A (en) * | 2016-11-02 | 2017-03-22 | 努比亚技术有限公司 | Prototype, security management and control method and security management and control system thereof |
CN106335289A (en) * | 2016-11-18 | 2017-01-18 | 深圳英诺激光科技有限公司 | Equipment and method for carrying out white or color marking on transparent material |
DE102017202269A1 (en) * | 2017-02-13 | 2018-08-16 | Sauer Gmbh | PROCESS FOR MACHINING A WORKPIECE SURFACE BY MEANS OF A LASER |
CN107685197A (en) * | 2017-09-22 | 2018-02-13 | 南京理工大学 | The processing unit (plant) and method of cutting are carried out to casting sand type using Linear Laser source |
CN109365995A (en) * | 2018-12-06 | 2019-02-22 | 哈尔滨工业大学 | A kind of preparation method of highly homogeneous microtip arrays structure |
CN109986212A (en) * | 2019-05-13 | 2019-07-09 | 大族激光科技产业集团股份有限公司 | A kind of laser color marking system and its method |
CN111230320B (en) * | 2020-03-16 | 2022-05-17 | 深圳泰德激光技术股份有限公司 | Laser marking method for surface of anodic aluminum oxide |
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US4547649A (en) * | 1983-03-04 | 1985-10-15 | The Babcock & Wilcox Company | Method for superficial marking of zirconium and certain other metals |
US5215864A (en) * | 1990-09-28 | 1993-06-01 | Laser Color Marking, Incorporated | Method and apparatus for multi-color laser engraving |
JPH0761198A (en) * | 1993-08-26 | 1995-03-07 | Yoshioka Fujio | Color marking method for metal by laser |
JPH07204871A (en) * | 1994-01-20 | 1995-08-08 | Fuji Electric Co Ltd | Marking method |
JP4762471B2 (en) * | 1999-11-11 | 2011-08-31 | コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ | Marking of anodized layers made of aluminum objects |
CN2477555Y (en) * | 2001-02-26 | 2002-02-20 | 宏全国际股份有限公司 | Packing vessel with raster mark |
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 |
US6710287B2 (en) * | 2002-08-22 | 2004-03-23 | Fu Sheng Industrial Co., Ltd. | Laser engraving and coloring method for a golf club head |
KR101123911B1 (en) * | 2003-08-19 | 2012-03-23 | 일렉트로 싸이언티픽 인더스트리이즈 인코포레이티드 | Methods of and laser systems for link processing using laser pulses with specially tailored power profiles |
US20060000814A1 (en) * | 2004-06-30 | 2006-01-05 | Bo Gu | Laser-based method and system for processing targeted surface material and article produced thereby |
GB0507465D0 (en) * | 2005-04-13 | 2005-05-18 | Renishaw Plc | Method of scale manufacture |
JP2007229778A (en) * | 2006-03-02 | 2007-09-13 | Toppan Printing Co Ltd | Marking method and apparatus |
WO2008091898A1 (en) * | 2007-01-23 | 2008-07-31 | Imra America, Inc. | Ultrashort laser micro-texture printing |
US20110089039A1 (en) * | 2009-10-16 | 2011-04-21 | Michael Nashner | Sub-Surface Marking of Product Housings |
KR20190095553A (en) * | 2011-03-10 | 2019-08-14 | 일렉트로 싸이언티픽 인더스트리이즈 인코포레이티드 | Anodized metallic article |
-
2011
- 2011-03-10 EP EP11860649.0A patent/EP2683520A4/en not_active Withdrawn
- 2011-03-10 WO PCT/US2011/027943 patent/WO2012121733A1/en active Application Filing
- 2011-03-10 KR KR1020137024517A patent/KR101881621B1/en active IP Right Grant
- 2011-03-10 CN CN201180009146.7A patent/CN103228399B/en not_active Expired - Fee Related
- 2011-03-10 JP JP2013557697A patent/JP2014509946A/en not_active Withdrawn
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JP2014509946A (en) | 2014-04-24 |
KR20140008522A (en) | 2014-01-21 |
KR101881621B1 (en) | 2018-07-24 |
WO2012121733A1 (en) | 2012-09-13 |
CN103228399B (en) | 2016-04-13 |
CN103228399A (en) | 2013-07-31 |
EP2683520A4 (en) | 2016-05-11 |
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