Methods for additively manufactured identification features

Abstract

Techniques for integrating a machine-readable matrix with a component of a mechanical structure using three-dimensional (3-D) printing are disclosed. Such techniques include generating at least one data model representing the component, and projecting a matrix pattern identifying one or more features of the component onto a selected surface portion of the component to produce a modified data model for use as an input to a 3-D printer.

Claims

1. A method of integrating a machine-readable matrix with a component of a mechanical structure using three-dimensional (3-D) printing, comprising: generating at least one data model representing the component; and projecting a matrix pattern identifying one or more features of the component onto a selected surface portion of the component to produce a modified data model for use as an input to a 3-D printer, wherein projecting the matrix pattern comprises integrating a 3-D matrix pattern into the selected surface to produce the modified data model, and wherein integrating the 3-D matrix pattern into the selected surface comprises selectively eliminating material below the selected surface to form the 3-D matrix pattern.

2. The method of claim 1, further comprising 3-D printing the component including the projected matrix pattern using the modified data model.

3. The method of claim 1, wherein the projecting the matrix pattern comprises at least one of translating, scaling, and rotating the matrix pattern relative to the selected surface portion.

4. The method of claim 1, wherein the projecting the matrix pattern comprises converting a two-dimensional (2-D) matrix pattern into a 3-D matrix pattern on the selected surface portion.

5. The method of claim 1, further comprising adding a plurality of surface textures to the matrix pattern.

6. The method of claim 1, further comprising varying an elevation of selected portions of the matrix pattern to create a machine-readable contrast.

7. The method of claim 6, wherein at least one elevated portion appears brighter to a machine reader and at least one portion lower than the at least one elevated portion appears darker to the machine reader to thereby create the machine-readable contrast.

8. The method of claim 1, further comprising adding coloration to the matrix pattern.

9. The method of claim 1, further comprising adding an infill to the matrix pattern.

10. The method of claim 1, further comprising 3-D printing the component using the modified data model.

11. A method of integrating a machine-readable matrix with a component of a mechanical structure using three-dimensional (3-D) printing, comprising: generating at least one data model representing the component; and projecting a matrix pattern identifying one or more features of the component onto a selected surface portion of the component to produce a modified data model for use as an input to a 3-D printer, wherein projecting the matrix pattern comprises integrating a 3-D matrix pattern into the selected surface to produce the modified data model, and integrating the 3-D matrix pattern into the selected surface comprises selectively adding material above the selected surface portion to form the 3-D matrix pattern.

12. The method of claim 11, further comprising 3-D printing the component including the projected matrix pattern using the modified data model.

13. The method of claim 11, wherein the projecting the matrix pattern comprises at least one of translating, scaling, and rotating the matrix pattern relative to the selected surface portion.

14. The method of claim 11, wherein the projecting the matrix pattern comprises converting a two-dimensional (2-D) matrix pattern into a 3-D matrix pattern on the selected surface portion.

15. The method of claim 11, further comprising adding a plurality of surface textures to the matrix pattern.

16. The method of claim 11, further comprising varying an elevation of selected portions of the matrix pattern to create a machine-readable contrast.

17. The method of claim 16, wherein at least one elevated portion appears brighter to a machine reader and at least one portion lower than the at least one elevated portion appears darker to the machine reader to thereby create the machine-readable contrast.

18. The method of claim 11, further comprising adding coloration to the matrix pattern.

19. The method of claim 11, further comprising adding an infill to the matrix pattern.

20. The method of claim 11, further comprising 3-D printing the component using the modified data model.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Various aspects of integrating data into AM components will now be presented in the detailed description by way of example, and not by way of limitation, in the accompanying drawings, wherein:

(2) FIG. 1 is a flow diagram illustrating an exemplary process of initiating 3-D printing.

(3) FIGS. 2A-D illustrate an exemplary powder bed fusion (PBF) system during different stages of operation.

(4) FIG. 3A is an example of a 2-D matrix code.

(5) FIG. 3B is an example of a 2-D matrix code having a different polarity and that contains identical data to matrix code of FIG. 3A.

(6) FIG. 4A shows an AM matrix projected to a 3-D surface facet in accordance with an aspect of the present disclosure.

(7) FIG. 4B shows a 2-D matrix projected onto a relatively flat surface facet of the 3-D model through translation, scaling, and rotation.

(8) FIG. 5 is an example of a code pitch dimension as measured on the 2-D matrix of FIG. 3A.

(9) FIG. 6 is a cross-sectional view of an extruded 3-D printed matrix made integral to an AM component.

(10) FIG. 7 is a sensor view of an extruded 3-D matrix 700 with a flat top upper surface.

(11) FIG. 8 is a cross-sectional view of a 3-D printed matrix having varying surface textures.

(12) FIG. 9 shows an illustration of a code-reading operation of a textured matrix in accordance with the present disclosure.

(13) FIGS. 10A-C show an illustration of variations of the matrix code reading process from three perspectives.

(14) FIG. 11 shows a cross section of a matrix that has been exposed to contamination.

DETAILED DESCRIPTION

(15) The detailed description set forth below in connection with the appended drawings is intended to provide a description of various exemplary embodiments of integrating data into AM components and is not intended to represent the only embodiments in which the invention may be practiced. The term “exemplary” used throughout this disclosure means “serving as an example, instance, or illustration,” and should not necessarily be construed as preferred or advantageous over other embodiments presented in this disclosure. The detailed description includes specific details for the purpose of providing a thorough and complete disclosure that fully conveys the scope of the invention to those skilled in the art. However, the invention may be practiced without these specific details. In some instances, well-known structures and components may be shown in block diagram form, or omitted entirely, in order to avoid obscuring the various concepts presented throughout this disclosure.

(16) The use of 3-D printing in the context of composite tooling provides significant flexibility for enabling manufacturers of mechanical structures and mechanized assemblies to manufacture parts with complex geometries. For example, 3-D printing techniques provide manufacturers with the flexibility to design and build parts having intricate internal lattice structures and/or profiles that are not possible to manufacture via traditional manufacturing processes.

(17) FIG. 1 is a flow diagram 100 illustrating an exemplary process of initiating an AM process. A data model of the desired 3-D object to be printed is rendered (step 110). A data model is a virtual design of the 3-D object. Thus, the data model may reflect the geometrical and structural features of the 3-D object, as well as its material composition. The data model may be created using a variety of methods, including 3D scanning, 3D modeling software, photogrammetry software, and camera imaging.

(18) 3D scanning methods for creating the data model may also use a variety of techniques for generating a 3-D model. These techniques may include, for example, time-of flight, volumetric scanning, structured light, modulated light, laser scanning, triangulation, and the like.

(19) 3-D modeling software, in turn, may include one of numerous commercially available 3-D modeling software applications. Data models may be rendered using a suitable computer-aided design (CAD) package, for example in an STL format. STL files are one example of a file format associated with commercially available CAD software. A CAD program may be used to create the data model of the 3-D object as an STL file. Thereupon, the STL file may undergo a process whereby errors in the file are identified and resolved.

(20) Following error resolution, the data model can be “sliced” by a software application known as a slicer to thereby produce a set of instructions for 3-D printing the object, with the instructions being compatible and associated with the particular 3-D printing technology to be utilized (step 120). Numerous slicer programs are commercially available. Slicer programs convert the data model into a series of individual layers representing thin slices (e.g., 100 microns thick) of the object be printed, along with a file containing the printer-specific instructions for 3-D printing these successive individual layers to produce an actual 3-D printed representation of the data model.

(21) A common type of file used for this purpose is a G-code file, which is a numerical control programming language that includes instructions for 3-D printing the object. The G-code file, or other file constituting the instructions, is uploaded to the 3-D printer (step 130). Because the file containing these instructions is typically configured to be operable with a specific 3-D printing process, it will be appreciated that many formats of the instruction file are possible depending on the 3-D printing technology used.

(22) In addition to the printing instructions that dictate what and how an object is to be rendered, the appropriate physical materials necessary for use by the 3-D printer in rendering the object are loaded into the 3-D printer using any of several conventional and often printer-specific methods (step 140). Powder bed fusion (PBF), for example, is an AM technique that uses a laser or other power source, along with a deflector, to fuse powdered material by aiming the laser or power source automatically at points in space defined by a 3-D model and binding the material together to create a solid structure. PBF includes within its scope various specific types of AM methods. Selective laser melting (SLM) and selective laser sintering (SLS), for instance, are PBF techniques in which print materials may be loaded as powders into a powder bed defined by a build plate and bordering walls (see FIGS. 2A-D). Layers of powder are deposited in a controlled manner into the powder bed for the power source to selectively manipulate on a layer-by-layer basis. Depending on the type of 3-D printer, other techniques for loading printing materials may be used. For example, in fused deposition modelling (FDM) 3-D printers, materials are often loaded as filaments on spools, which are placed on one or more spool holders. The filaments are typically fed into an extruder apparatus which, in operation, heats the filament into a melted form before ejecting the material onto a build plate or other substrate.

(23) Referring back to FIG. 1, the respective data slices of the 3-D object are then printed based on the provided instructions using the material(s) (step 150). In 3-D printers that use laser sintering, a laser scans a powder bed and melts the powder together where structure is desired, and avoids scanning areas where the sliced data indicates that nothing is to be printed. This process may be repeated thousands of times until the desired structure is formed, after which the printed part is removed from a fabricator. In fused deposition modelling, parts are printed by applying successive layers of model and support materials to a substrate. In general, any suitable 3-D printing technology may be employed for purposes of this disclosure.

(24) FIGS. 2A-D illustrate respective side views of an exemplary PBF system 200 during different stages of operation. As noted above, the particular embodiment illustrated in FIGS. 2A-D is one of many suitable examples of a PBF system employing principles of this disclosure. It should also be noted that elements of FIGS. 2A-D and the other figures in this disclosure are not necessarily drawn to scale, but may be drawn larger or smaller for the purpose of better illustration of concepts described herein. PBF system 200 can include a depositor 201 that can deposit each layer of metal powder, an energy beam source 203 that can generate an energy beam, a deflector 205 that can apply the energy beam to fuse the powder, and a build plate 207 that can support one or more build pieces, such as a build piece 209. PBF system 200 can also include a build floor 211 positioned within a powder bed receptacle. The walls of the powder bed receptacle 212 generally define the boundaries of the powder bed receptacle, which is sandwiched between the walls 212 from the side and abuts a portion of the build floor 211 below. Build floor 211 can progressively lower build plate 207 so that depositor 201 can deposit a next layer. The entire mechanism may reside in a chamber 213 that can enclose the other components, thereby protecting the equipment, enabling atmospheric and temperature regulation and mitigating contamination risks. Depositor 201 can include a hopper 215 that contains a powder 217, such as a metal powder, and a leveler 219 that can level the top of each layer of deposited powder.

(25) Referring specifically to FIG. 2A, this figure shows PBF system 200 after a slice of build piece 209 has been fused, but before the next layer of powder has been deposited. In fact, FIG. 2A illustrates a time at which PBF system 200 has already deposited and fused slices in multiple layers, e.g., 150 layers, to form the current state of build piece 209, e.g., formed of 150 slices. The multiple layers already deposited have created a powder bed 221, which includes powder that was deposited but not fused.

(26) FIG. 2B shows PBF system 200 at a stage in which build floor 211 can lower by a powder layer thickness 232. The lowering of build floor 211 causes build piece 209 and powder bed 221 to drop by powder layer thickness 232, so that the top of the build piece and powder bed are lower than the top of powder bed receptacle wall 212 by an amount equal to the powder layer thickness. In this way, for example, a space with a consistent thickness equal to powder layer thickness 232 can be created over the tops of build piece 209 and powder bed 221.

(27) FIG. 2C shows PBF system 200 at a stage in which depositor 201 is positioned to deposit powder 217 in a space created over the top surfaces of build piece 209 and powder bed 221 and bounded by powder bed receptacle walls 212. In this example, depositor 201 progressively moves over the defined space while releasing powder 217 from hopper 215. Leveler 219 can level the released powder to form a powder layer 225 that has a thickness substantially equal to the powder layer thickness 232 (see FIG. 2B). Thus, the powder in a PBF system can be supported by a powder support structure, which can include, for example, a build plate 207, a build floor 211, a build piece 209, walls 212, and the like. It should be noted that the illustrated thickness of powder layer 225 (i.e., powder layer thickness 232 (FIG. 2B)) is greater than an actual thickness used for the example involving 150 previously-deposited layers discussed above with reference to FIG. 2A.

(28) FIG. 2D shows PBF system 200 at a stage in which, following the deposition of powder layer 225 (FIG. 2C), energy beam source 203 generates an energy beam 227 and deflector 205 applies the energy beam to fuse the next slice in build piece 209. In various exemplary embodiments, energy beam source 203 can be an electron beam source, in which case energy beam 227 constitutes an electron beam. Deflector 205 can include deflection plates that can generate an electric field or a magnetic field that selectively deflects the electron beam to cause the electron beam to scan across areas designated to be fused. In various embodiments, energy beam source 203 can be a laser, in which case energy beam 227 is a laser beam. Deflector 205 can include an optical system that uses reflection and/or refraction to manipulate the laser beam to scan selected areas to be fused.

(29) In various embodiments, the deflector 205 can include one or more gimbals and actuators that can rotate and/or translate the energy beam source to position the energy beam. In various embodiments, energy beam source 203 and/or deflector 205 can modulate the energy beam, e.g., turn the energy beam on and off as the deflector scans so that the energy beam is applied only in the appropriate areas of the powder layer. For example, in various embodiments, the energy beam can be modulated by a digital signal processor (DSP).

(30) As noted above, parts that are additively manufactured are typically designed as part of a 3-D data model. By contrast, typical data matrices are a mathematical model of a flat, two-dimensional, binary black-and-white surface pattern similar to a printed paper label. These properties make such a data representation incompatible for integration into AM components. To avoid such incompatibilities and the conventional deficiencies discussed above with respect to conventional solutions, the method herein broadly contemplates directly associating the matrix permanently into the AM part in an immutable way.

(31) FIG. 3A is an example of a 2-D matrix code 300. Matrix codes are symbols that require regions with high contrast relative to one another, such as light zones 302 and dark zones 304, to enable good legibility. Conventionally, good legibility has been attained by printing black ink onto a light-colored label, a process that generally yields a strong contrast. This conventional approach involves a two-step process to first produce the label—namely, make the paper tab and mark it accordingly—and second to attach the label to the component. Process deviations in design and manufacturing, and in field use including the malicious influences described above, can introduce unpredictable errors or result in tampering activities.

(32) FIG. 3B is an example of a 2-D matrix code 306 that contains identical data to matrix code 300 of FIG. 3A. The matrices 300 and 306 have the same pattern and internal shapes, but differ with respect to their bright-dark polarity. For example, shapes 306A and 306B are the same but with dark inverted to light and vice versa. Similarly, shapes 308A and 308B are the same but with light inverted to dark and vice versa. This general polarity reversal pattern persists throughout matrices 300 and 306. The matrix polarity is not relevant to the reader in the sense that both polarities may be interpreted to read as the same data text. In short, information is conveyed in these labels because the dark and light zones in the matrices 300 and 306 create contrast when viewed by a barcode reader. This information may be included in the location of the light-dark transitions.

(33) In one aspect of the disclosure, a 3-D machine-readable data matrix integrated into an AM component is disclosed. In an embodiment, the techniques as described herein integrate the steps described above with reference to FIGS. 3A-B into a single AM step and permanently integrate the data matrix into the shape of the original AM component. In the initial design process, a 3-D matrix pattern may be integrated into a part. This is accomplished by projecting a 2-D pattern of the matrix into 3-D space and onto the plane of an identified surface of a 3-D data model. Using this technique, the matrix pattern can be translated and rotated to be rendered consistent with the part's relevant surface facet. In an embodiment, a part may be scaled in order to accommodate a relatively flat facet area for this purpose.

(34) FIG. 4A shows a 2-D AM matrix 400 projected onto a 3-D surface facet in accordance with an embodiment. The 2-D matrix 400 is shown segmented into black and white zones 402. However, it will be appreciated that colors may in some instances not be realizable or available during the AM process. The projection of FIG. 4A may be accomplished by selecting a desirable flat surface facet area on the 3-D component to be additively manufactured and projecting the matrix pattern onto the surface facet of the 3-D model.

(35) In an embodiment, the particular location on the part is selected for its visibility and accessibility, whether with the part in isolation or with the part as assembled into its operating position within a larger structure, such as a vehicle. This facet selection may involve tradeoffs or design compromises. For example, the part as designed may not have a suitable surface facet. In this case, the part may in some instances be redesigned to incorporate a flat area to accommodate this feature. Further, while there may be accessible and visible flat surface facets for the isolated part, the part as assembled into a larger structure may not have any accessible such surface facets. Accordingly, in some embodiments, various design changes may be considered and implemented in order to facilitate a view of the matrix on the part. In short, changes may be required to present a suitably visible surface facet to act as a machine-readable label or nameplate on a moving part. These and other aspects may be taken into consideration during the design phase of the AM process.

(36) In one embodiment, the matrices generated may be compatible with all reader types, including a barcode type reader, LED and laser illumination readers, ambient techniques, lens-based imaging, scanning, and the like.

(37) FIG. 4B shows a 2-D matrix 404 projected onto a relatively flat surface facet of the 3-D model through translation, scaling, and rotation. After these steps, the projected matrix has been elevated such that regions corresponding to light zones 406A (FIG. 4A) have been elevated as shown by region 406B (FIG. 4B) and may be 3-D printed at the part surface 410. Conversely, regions corresponding to dark zones 408A (FIG. 4A) may be inset as shown by region 408B (FIG. 4B) into the part surface 410. In an embodiment, readable contrast may be created using any one or more of three techniques. First, a surface texture differential may be generated to reflect illumination differently (see FIGS. 8-11). Second, shadows may be generated in areas of varying elevation using differential block illumination. For this technique, elevations above and below the surface may cast shadows that darken certain areas such that, for example, upper surfaces may be illuminated and appear bright, while lower surfaces may be shadowed and appear dark. Vertical wall surfaces may be obscured by relatively sharp normal reading angles relative to the surface of the projected matrix. Third, coloration or infill such as paint may be used as a post-processing step.

(38) As is evident from matrix 404 of FIG. 4B, the dark zones 408B of the matrix pattern may be projected downward vertically to form a prismatic indentation below the part surface. This effect forms a relieved 3-D representation of the matrix into the surface of the data model. The resulting matrix 404 may resemble a carving on the part surface. Inset dark zones 408B may create shadows that produce matrix contrast. Light zones 406B may remain elevated at surface level and may cast shadows into the dark zones 408B. This shadowing effect exploits the offset between the illuminator and the sensor, which offset may vary but in some embodiments may be approximately 15-45 degrees. In general, at larger illumination offsets and deeper inset distances, this shadowing effect may create readable contrast.

(39) FIG. 5 is an example of a code pitch dimension 502 as measured on the 2-D matrix 500 of FIG. 3A. Code pitch dimension 502 is defined as the smallest discrete unit on the matrix. Code pitch dimension 502 determines the spatial resolution of the encoded information in the matrix. This dimension generally sets the limit of standoff distance and readability for barcode readers and camera sensors that can read the data in the matrix 500.

(40) FIG. 6 is a cross-sectional view of an extruded 3-D printed matrix 600 made integral to an AM component. Code pitch dimension CP (602) is represented in this embodiment by a cross-sectional width of the smallest feature in the matrix. FIG. 6 also shows relief depth dimension RDD (604), which defines the well depth to which the matrix pattern may be inset below the AM component surface. In this exemplary embodiment, the relief depth dimension is two code-pitch lengths such that RDD=2×CP. Thus, in one embodiment, the inset below the AM part surface may be set such that the relief depth dimension is twice the code pitch. It will be appreciated that this quantity is illustrative in nature, and other dimensions may be equally suitable.

(41) While a native matrix material may be selected and used during the component's AM process to form the readable matrix pattern, this pattern may not provide an optical contrast between the matrix and base 606. That is, because these homogenous zones exhibit no contrast between dark and light areas, the matrix may not be readable to a sensor or barcode reader. For example, in the cases of black-on-black or white-on-white marking, the low contrast may not be visible. Thus, in accordance with another aspect of the disclosure, contrast-enhancing features may be incorporated into the component data model and integrated with the AM process of the component.

(42) FIG. 7 is a sensor view of an extruded 3-D matrix 700 with a flat top upper surface. The matrix 700 includes light zone 702 and dark zone 704 and has a similar pattern as the matrix of FIG. 3A. In this example, the matrix pattern 700 has been formed into the homogenous material of the subject component. Dark zone 306A of FIG. 3A corresponds to dark zone 704 in FIG. 7. Similarly, light zone 308A of FIG. 3A corresponds to light zone 702 in FIG. 7. The apparent contrast between dark and light zones relative to a sensor viewing the matrix at an angle substantially orthogonal to the matrix surface may be poor, having been lost as a side-effect of the AM process. Thus, in this instance, it may be difficult or impossible for a reader to reliably find the matrix or to read the data content encoded therein.

(43) In one embodiment, a more deeply inset pattern may be used to recover some of the lost resolution. In another embodiment, in cases where the AM component is not capable of providing a deeper pattern or where such a pattern is otherwise impractical, dark and light areas may be programmed having different textures. In an exemplary embodiment, a surface texturing contrast creation mechanism is employed. Contrast may be created, for example, through differential texturing incorporated into the surface of the AM matrix. The texture may interfere with the illumination either constructively or destructively as described hereinafter, thereby creating dark and light zones.

(44) FIG. 8 is a cross-sectional view of a 3-D printed matrix 800 having varying surface textures. In this embodiment, dark and light areas may be programmed with different textures. The surface finish and textured topography of a textured matrix may interact with illumination of a reader to produce a strong contrast and a reliable, readable matrix symbology pattern. The matrix 800 may include a part surface 802, a specular well zone 804, and a textured zone 806. The part surface 802 may be planar or relatively flat. If no matrix were printed, the part surface 802 would extend uniformly flat across the top of the figure. In this example, the matrix 800 is formed entirely by eliminating material below the part surface 802. However, in other embodiments, matrices can also be formed at the part surface 802 or elevated and protruding above the part surface 802. Recession below the surface to well zones 804 may be advantageous in some instances because the indented shape of textured zones 806 may provide protection of the matrix symbols and patterns against frictional wear and tear and other trauma.

(45) The textured zones 806 may reflect light at different angles than the more indented well zones 804. This effect may be enhanced at certain viewing angles as a result of the obscuration and shadowing caused by matrix recession. The relieved geometry of the matrix 800 and its textures may be arranged to create visible contrast under most lighting conditions with both structured and ambient light. Effective contrast may therefore be achieved under a variety of common viewing conditions and the matrix reading process may be made more reliable as a result.

(46) FIG. 9 shows a code-reading operation of a textured matrix 900 in accordance with the present disclosure. An illumination source 902 may generate light 903 that is directed onto the AM component and corresponding matrix 900. The matrix 900 may include a plurality of canted ridges 906 and recessed wells 908. The light 902 may be reflected differentially off canted ridges 906 and recessed wells 908. The reflected light 920 may thereupon be scattered differentially by the two textures and respective elevations. This scattering may create a contrasting pattern between the light and dark zones of the matrix 900.

(47) The pattern of reflected light and dark areas constituting the matrix symbology may be received by sensor 904. Thereupon, an image of the matrix pattern may be formed in the sensor and processed to extract its symbolic content and geometric metadata including, for example, 3-D position, 3-D orientation, etc.

(48) FIGS. 10A-C show an illustration of variations of the matrix code reading process from three perspectives. FIGS. 10A-C show illuminators 1002A-C and sensors 1004A-C, respectively. Referring initially to the example of FIG. 10A, matrix 1010 includes textured surfaces 1008 and specular well zones 1006. As shown, sensor 1004A is at an offset viewing angle relative to matrix 1010 and illuminator 1002A is on axis with sensor 1004A such that illuminator 1002A directs light to matrix 1010 at substantially the same angle as sensor 1004A receives it. The sensor 1004A and illuminator 1002A are in a nearly coaxial position and the field of illumination is nearly coincident with the field of view of sensor 1004A. Thus, because the light 1012 is coincident with textured surfaces 1008, reflected light 1014 from textured surfaces 1008 is bright and specular well zones 1006 are dark, which may correspond to a normal polarity.

(49) More specifically, as illuminator 1002A emits light 1012, the textured surface 1008 of matrix 1010 may reflect light 1014 from bright zones into the sensor 1004A and the specular well zones 1006 may deflect light 1016 in a different direction. A readable contrast is thereby achieved.

(50) Referring to FIG. 10B, sensor 1004B is at a normal (orthogonal) viewing angle relative to matrix 1020 and illumination of light 1014 from illuminator 1002B is on axis with sensor 1004B. Thus, because the direction of light 1014 is normal to specular well zones 1006 rather than the textured surfaces 1008, the textured surfaces 1008 in this embodiment are dark, the specular well zones 1006 are bright, and the polarity is inverted. Here, light 1022 from the specular well zones 1006 may be reflected directly back to sensor 1004B. The dashed lines 1016 represent the angle of any illumination differentially reflected from dark textured surfaces 1008, which is advantageously different from the angle at which light 1022 is reflected from bright specular well zones 1006. A good readable contrast may be achieved in this example as well.

(51) Referring to FIG. 10C, sensor 1004C is at a normal viewing angle relative to specular matrix 1030 and specular well zones 1006. Illuminator 1002C is off-axis relative to sensor 1004C by an angle θ. In this example, light 1032 from illuminator 1002C arrives at angle θ substantially coincident with textured surfaces 1008. The textured surfaces 1008 consequently may reflect light 1034 directly toward the viewing angle of sensor 1004. By contrast, light 1030 reflected from the specular wells 1006 may be differentially reflected away from a viewing angle of sensor 1004C. Thus, in this embodiment, textured surfaces 1008 are bright, specular wells 1006 are dark and the polarity is normal. A good readable contrast may be achieved in this situation.

(52) In another aspect of the disclosure, a technique for reducing contamination exposure in 3-D integrated matrices is disclosed. In addition to creating visible contrast, matrix recession such as in the embodiment of FIGS. 10A-C may improve resistance to contamination. Contamination of surfaces may be common, for example, in outdoor environments where the part may be exposed to dirt, grease, road dust and the like. Accumulated contamination may potentially obscure or interfere with the operation of sensors 1004A-C or other devices that may be used read the matrix symbology.

(53) FIG. 11 shows a cross section of a matrix 1100 that has been exposed to contamination. The matrix includes component surface 1100, well zones 1104A-C, and textured zones 1106A-B. As is evident from the illustration, well zones 1104A-C and textured zones 1106A-B have indentations where contaminants may accumulate. Two of the well zones 1104B-C have been exposed to a contaminant 1108. Similarly, one of the textured zones 1106b has been exposed to a contaminant 1110. The contaminating substance may include, for example, substances like dirt, grease, mud, or other fine granular foreign substances. The contaminating substance may further include some mixture of organic and inorganic materials.

(54) As is further evident from the illustration, one of well zones 1104A and one of textured zones 1106A are free from contamination. Well zone 1104A is deeper than the indentations in textured zones 1106A-B. Further, well zone 1104C is wider than the indentations in textured zones 1106A-B. For these reasons, well zones 1104A and 1104C may be able to sustain a greater accumulated bulk of contaminated material before becoming corrupted. Similarly, well zones 1104A and 1104C may also accommodate larger particles with larger overall grain size. Because the identified well zones are deeper and/or wider, the bulk of contamination may therefore accumulate in the well zones 1104A and 1104C and not in the textured surfaces 1106A-B.

(55) Particulate matter generally scatters light broadly, as opposed to the relatively flat and smooth specular surfaces of the AM component. The small amount of contaminated material 1110 captured in textured surface 1106B may therefore be relatively insignificant. This feature provides an inherent difference in optical characteristics of the relative surfaces, which in turn may translate to a strong contrast between the light and dark zones. To this end, accumulated contamination may actually reinforce and improve the readability of the matrix symbology produced according to these embodiments. This optical feature further reinforces immunity to contamination and therefore overall reliability of the integrated matrix.

(56) The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these exemplary embodiments presented throughout this disclosure will be readily apparent to those skilled in the art, and the concepts disclosed herein may be applied to other techniques for integrating 3-D matrices into parts. Thus, the claims are not intended to be limited to the exemplary embodiments presented throughout the disclosure, but are to be accorded the full scope consistent with the language claims. All structural and functional equivalents to the elements of the exemplary embodiments described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. § 112(f), or analogous law in applicable jurisdictions, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.”