Patent Publication Number: US-2022222468-A1

Title: Additive manufacturing counterfeiting obfuscation

Description:
FIELD 
     The present disclosure relates to additive manufacturing and preventing counterfeit additive manufactured parts. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
     The manufacture and sale of counterfeit additive manufactured parts is of concern to original equipment manufacturers (OEMs) and consumers. For example, the manufacture of additive manufactured parts using inferior material(s) can lead to less than desired performance of such parts. And while digital file security methods have been and are currently being developed, such methods can be cost prohibitive. 
     The present disclosure addresses the issues of counterfeit additive manufacturing among other issues related to additive manufacturing of parts. 
     SUMMARY 
     This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features. 
     In one form of the present disclosure, a method of forming an additive manufactured part with obfuscated anti-counterfeiting features includes additive manufacturing the part using an approved additive manufacturing method and additive manufacturing a plurality of obfuscated anti-counterfeiting structures on a surface of the part using the approved additive manufacturing method. Each of the plurality of obfuscated anti-counterfeiting structures comprises at least one of a prohibitive physical dimension and a prohibitive physical shape that is prohibitive from being formed using at least one unapproved additive manufacturing method such that counterfeit manufacture of the part by the at least one unapproved additive manufacturing method is detected by inspecting the surface or observing a build failure by the at least one unapproved additive manufacturing method. 
     In some variations, the prohibitive physical dimension is at least one of an average inner dimension of the plurality of obfuscated anti-counterfeiting structures, an average outer dimension of the plurality of obfuscated anti-counterfeiting structures, an average spacing between the plurality of obfuscated anti-counterfeiting structures, an average height of the plurality of obfuscated anti-counterfeiting structures, an average width of the plurality of obfuscated anti-counterfeiting structures, an average length of an unsupported section of the plurality of obfuscated anti-counterfeiting structures, and an average overhang angle of an unsupported section of the plurality of obfuscated anti-counterfeiting structures. 
     In at least one variation, the plurality of obfuscated anti-counterfeiting structures is a plurality of hollow structures, the approved additive manufacturing method is one of multi jet fusion, selective laser sintering, fused filament fabrication, direct metal laser melting, binder jetting, and material jetting, and the unapproved additive manufacturing method is one of continuous liquid interface production and stereolithography. In such variations, the plurality of hollow structures have a prohibitive physical dimension in the form of an average inner dimension between about 1 mm and about 5 mm. And in some variations, the plurality of hollow structures is at least one of a plurality of hollow spheres, a plurality of hollow cylinders, a plurality of hollow cones, and a plurality of hollow polyhedral. In at least one variation the plurality of hollow structures have a prohibitive physical dimension in the form an average wall thickness between about 1 mm and about 5 mm. 
     In some variations, the plurality of obfuscated anti-counterfeiting structures is a plurality of solid structures, the approved additive manufacturing method is one of multi jet fusion, fused filament fabrication, binder jetting, and material jetting, and the unapproved additive manufacturing method is selective laser sintering and direct metal laser melting. In such variations, the plurality of solid structures have a prohibitive physical dimension in the form average an outer dimension between about 5 mm and about 10 mm. And in some variations the plurality of solid structures is at least one of a plurality of solid spheres, a plurality of solid cylinders, a plurality of solid cones, and a plurality of solid polyhedra. In at least one variation the plurality of solid structures have a prohibitive physical dimension in the form an average spacing between adjacent solid structures between about 5 mm and about 25 mm. 
     In some variations, the plurality of obfuscated anti-counterfeiting structures is a plurality of truss structures, the approved additive manufacturing method is multi jet fusion, selective laser sintering, stereolithography, binder jetting, high speed sintering, direct metal laser melting, and the unapproved additive manufacturing method is fused filament fabrication, stereolithography, and direct metal laser melting. And in some variations the plurality of truss structures have a prohibitive physical dimension in the form an average outer dimension between about 1 mm and about 3 mm. In at least one variation the plurality of obfuscated anti-counterfeiting structures comprises at least two of a plurality of hollow structures, a plurality of solid structures, and a plurality of truss structures. In some variations, the unapproved additive manufacturing method is at least two unapproved additive manufacturing methods and the plurality of obfuscated anti-counterfeiting structures is a plurality of hollow structures and a plurality of truss structures. 
     In at least one variation the surface of the part is a B-surface of the part. 
     In another form of the present disclosure, a method of forming additive manufactured parts with obfuscated anti-counterfeiting features includes additive manufacturing a plurality of parts using an approved additive manufacturing method by forming a plurality of obfuscated anti-counterfeiting structures on a surface of each of the plurality of parts. Each of the plurality of obfuscated anti-counterfeiting structures includes at least one of a prohibitive physical dimension and a prohibitive physical shape that is prohibitive from being formed using at least one unapproved additive manufacturing method such that counterfeit manufacture of the plurality of parts by the at least one unapproved additive manufacturing method is detected by inspecting the surface of each of the plurality of parts or observing a build failure by the at least one unapproved additive manufacturing method. 
     In some variations, the plurality of obfuscated anti-counterfeiting structures is at least one of a plurality of hollow structures with a prohibitive physical dimension in the form of an average inner dimension between about 1 mm and about 5 mm, a plurality of solid structures with a prohibitive physical dimension in the form an average outer dimension between about 5 mm and about 10 mm, and a plurality of truss structures with a prohibitive physical dimension in the form an average outer dimension between about 5 mm and about 10 mm. And in at least one variation the surface of each of the plurality of parts is a B-surface. 
     In still another form of the present disclosure, a method of forming additive manufactured parts with obfuscated anti-counterfeiting features includes additive manufacturing a plurality of parts using at least one approved additive manufacturing method such that each of the plurality of parts has a surface with a plurality of obfuscated anti-counterfeiting structures. In some variations, the plurality of obfuscated anti-counterfeiting structures includes at least two of a plurality of hollow structures, a plurality of solid structures, and a plurality of truss structures. Also, each of the plurality of obfuscated anti-counterfeiting structures includes at least one of a prohibitive physical dimension and a prohibitive physical shape that is prohibitive from being formed using at least one unapproved additive manufacturing method such that counterfeit manufacture of the plurality of parts using at least two unapproved additive manufacturing methods is detected by inspecting the surface or observing a build failure by the at least one unapproved additive manufacturing method. 
     In some variations, the plurality of obfuscated anti-counterfeiting structures is at least two of a plurality of hollow structures with a prohibitive physical dimension in the form an average inner dimension between about 1 mm and about 5 mm, a plurality of solid structures with a prohibitive physical dimension in the form an average outer dimension between about 5 mm and about 10 mm, and a plurality of truss structures with a prohibitive physical dimension in the form an average outer dimension between about 5 mm and about 10 mm. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which: 
         FIG. 1A  is a perspective view of a component formed by additive manufacturing; 
         FIG. 1B  is a perspective view of the component in  FIG. 1A  with obfuscated anti-counterfeit structures on a surface of the component according to one form of the present disclosure; 
         FIG. 1C  is a perspective view of the component in  FIG. 1A  with obfuscated anti-counterfeit structures on a surface of the component according to another form of the present disclosure; 
         FIG. 2A  is a side view of a binder jetting system according to one form of the present disclosure; 
         FIG. 2B  is a side view of a material jetting system according to the teachings of the present disclosure; 
         FIG. 2C  is a side view of a selective laser sintering and/or direct metal laser meting system according to the teachings of the present disclosure; 
         FIG. 2D  is a side view of a stereolithography system according to the teachings of the present disclosure; 
         FIG. 2E  is a side view of a continuous liquid interface production according to the teachings of the present disclosure; 
         FIG. 2F  is a side view of a material jetting system according to the teachings of the present disclosure; 
         FIG. 2G  is a side view of fused filament fabrication system according to the teachings of the present disclosure; 
         FIG. 3  is a perspective exploded view of a center console assembly for a motor vehicle; 
         FIG. 4  is a sectional view of section A-A in  FIG. 3  according to one form of the present disclosure; 
         FIG. 5  is a sectional view of section A-A in  FIG. 3  according to another form of the present disclosure; 
         FIG. 6  is a sectional view of section A-A in  FIG. 3  according to still another form of the present disclosure; 
         FIG. 7  is a sectional view of section A-A in  FIG. 3  according to yet another form of the present disclosure; and 
         FIG. 8  is a flowchart for a method of additive manufacturing a component with obfuscated anti-counterfeit structures according to the teachings of the present disclosure. 
     
    
    
     The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
     The present disclosure provides a method for additive manufacturing a part with anti-counterfeit structures or features that inhibit manufacture of the part using unapproved manufacturing techniques. For example, the method includes additive manufacturing (AM) a part using an approved AM method such that the part has at least one surface with a plurality of obfuscated anti-counterfeiting structures (also referred to herein simply as “obfuscated anti-counterfeiting structures”) that are properly formed with the approved AM method but cannot be properly formed with an unapproved AM method. Accordingly, AM of the part using an unapproved AM method can be detected by inspecting the at least one surface of the part and determining whether or not a plurality of obfuscated anti-counterfeiting structures are present on the surface, and if present, are the obfuscated anti-counterfeiting structures properly formed. If the plurality of obfuscated anti-counterfeiting structures are not present, than an original equipment manufacturer (OEM) or approved contractor of the OEM is alerted that the part has been manufactured by an unauthorized entity. Also, if the plurality of obfuscated anti-counterfeiting structures are present on the at least one surface and are not properly formed (i.e., defects are present), then the OEM is alerted that the part has been manufactured by an unauthorized entity. In the alternative, or in addition to, AM of the part using an unapproved AM method can be detected by observing a build failure by the at least one unapproved additive manufacturing method. 
     As used herein, the phrase “approved AM method” refers to an AM method or technique that is specified, certified and/or approved by an original equipment manufacturer (OEM) for the manufacture of one or more parts, and the phrase “unapproved AM method” refers to an AM method or technique that is not specified, certified and/or approved by an OEM for the manufacture of the same one or more parts. Also, the phrase “obfuscated anti-counterfeiting structures” refers to a plurality of structures on a surface of a given AM part that can be properly formed using an approved AM method(s) to form the AM part but cannot be properly formed using an unapproved AM method(s). And as used herein, the phrase “properly formed” refers to structures that are formed with an approved AM method and meet specifications and/or tolerances of the part required by the OEM as established or set forth under a Part Production Approval Process (PPAP) for the part. 
     In some variations, each of the plurality of obfuscated anti-counterfeiting structures has at least one of a physical dimension and a physical shape that is properly formed using an approved AM method but is prohibitive from being formed using an unapproved AM method as described in greater below. Accordingly, the present disclosure provides a method of ensuring authorized AM of parts. As used herein, the phrase “prohibitive from being formed” refers to a structure, a physical dimension of the structure and/or a physical shape of the structure that cannot be properly formed using a given AM method. 
     Referring to  FIGS. 1A-1C ,  FIG. 1A  shows a perspective view of an AM part  50  with a surface  500  that does not have obfuscated anti-counterfeiting structures and  FIGS. 1B-1C  show two non-limiting examples of parts with obfuscated anti-counterfeiting structures. Particularly,  FIG. 1B  shows the AM part  50  in  FIG. 1A  with obfuscated anti-counterfeiting structures in the form of hollow structures  514  formed on the surface  500 . And  FIG. 1C  shows the AM part  50  in  FIG. 1A  with obfuscated anti-counterfeiting structures in the form of truss structures  518  formed on the surface  500 . 
     The hollow structures  514  illustrated in  FIG. 1B  are properly formed with approved AM methods such as multi jet fusion, fused filament fabrication, material jetting, selective laser sintering, binder jetting, and direct metal laser melting (assuming the part is made from a metallic material) such that the hollow structures  514  do not have or exhibit structural defects such as capping. However, the hollow structures  514  are not properly formed with unapproved AM methods such as continuous liquid interface production and stereolithography. That is, the hollow structures  514  formed using AM methods such as continuous liquid interface production or stereolithography will have or exhibit structural defects such as capping and/or delamination from the surface  500  due to negative pressure within the hollow structures  514 . 
     The truss structures  518  illustrated in  FIG. 1C  are properly formed with approved additive manufacturing method such as multi jet fusion, selective laser sintering, stereolithography, binder jetting, and direct metal laser melting such that the truss structures  518  do not have or exhibit structural defects such as sagging. However, the truss structures  518  are not properly formed with unapproved AM methods such as fused filament fabrication and direct metal laser melting. That is, the truss structures  518  formed using AM methods such as fused filament fabrication or direct metal laser melting will have or exhibit structural defects such as sagging and/or delamination from the surface  500 . 
     In some variations, the part  50  is an automotive part, e.g., a part for an interior or engine compartment of a motor vehicle. It should be understood that the part  50  can be manufactured using different AM methods with at least one AM method being desired for forming the part  50  due to chemical, physical, and/or mechanical properties of the properly formed part  50 . Stated differently, geometric freedoms available via AM provide an additional functionality of embedding specific design features in a part that increase the difficulty of counterfeit manufacturing the part using an uncertified (i.e., unapproved) AM method. In addition, the specific design features are tailored to negatively impact the manufacture of parts using unapproved AM methods. However, AM the parts using an approved AM method provides for a part with aspects such as weight, performance, and cost being changed within an acceptable amount or degree. 
     In order to better illustrate the teachings of the present disclosure, a non-limiting summary or review of AM methods that can be approved AM methods and/or unapproved AM methods, depending on design features of a part, are discussed below. 
     Referring now to  FIGS. 2A-2G , non-limiting examples of AM methods that are approved AM methods, or in the alternative, unapproved AM methods depending on the design features of a given part are shown. Particularly,  FIGS. 2A-2C  show systems that use or employ at least one bed of powder during AM of parts, FIGS.  2 D- 2 E show systems that use or employ a liquid bath during AM of parts, and  FIGS. 2F-2G  show systems that use or employ deposition devices to deposit layers of material onto previously deposited layers during AM of parts. 
     Referring particularly to  FIG. 2A , a system  10  for AM a part  160  via binder jetting (BJ) is shown. The system  10  includes a first powder bed  100  on a first elevator platform  110  and a powder roller  120  configured to transfer powder ‘P’ from the first powder bed  100  to a second powder bed  130  that is part of or contained within a build box  140  that includes a second elevator platform  142 . A binder nozzle  150  (e.g., an inkjet print head) is included and configured to move and deposit a liquid binder  152  at desired or selected locations across an upper surface  132  of the powder bed  130 . The desired or selected locations of the upper surface  132  with liquid binder  152  form a layer (e.g., a first layer—not labeled) of the part  160 . After the first layer is formed, the second elevator platform  142  moves downward (−z direction) and the powder roller  120  transfers powder P from the first powder bed  100  to the second powder bed  130  and spreads a thin layer (not labeled) of the powder P across the previously formed first layer of the part  160 . Then the binder nozzle  150  moves across the powder bed  130  and deposits the liquid binder  152  at desired or selected locations across the upper surface  132  of the powder bed  130  to form a second layer (not labeled) of the part  160 . This cycle, i.e., powder—binder—powder—binder, continues until the part  160  is formed layer by layer. In some variations the part  160  is subjected to additional processing such as depowdering, washing, and sintering, among others. 
     It should be understood that BJ AM can be used to form hollow structures without the presence of “cupping” defects (i.e., a depression in the wall of a hollow structure) and solid structures without warpage and/or shrinkage. Accordingly, BJ AM can be an approved AM method for forming parts with at least one surface having obfuscated anti-counterfeiting structures in the form of hollow structures (e.g., the part  50  shown in  FIG. 1B ) and/or solid structures. 
       FIG. 2B  shows a system  12  for AM the part  160  via multi jet fusion (MJF). The system  12  includes the second powder bed  130  on the second elevator platform  142  and a material recoating unit  180  configured to apply powder ‘P’ over the powder bed  130  in the build box  140 . A printer head  170  with an inkjet array  172  (only one inkjet shown), a fusing and detailing agent array  174  (only one shown), and an energy unit  176  (e.g., a thermal energy unit or an ultraviolet light energy unit), is included. The printer head  170  is configured to move and deposit a liquid binder via the inkjet array  172  and/or fusing and detailing agents via the fusing and detailing agent array  174  at desired or selected locations across an upper surface  132  of the powder bed  130 . In addition, the desired or selected locations of the upper surface  132  with liquid binder and/or fusing and detailing agents form a layer (e.g., a first layer—not labeled) of the part  160  that is cured via exposure to or irradiation from the energy source  176 . After the first cured layer is formed, the second elevator platform  142  moves downward (−z direction) and the material recoating unit  180  provides or deposits a thin layer of powder P across the previously formed first cured layer of the part  160 . Then the printer head  170  moves across the powder bed  130  and deposits the liquid binder and/or fusing and detailing agents at desired or selected locations across the upper surface  132  of the powder bed  130  to form a second layer (not labeled) of the part  160  which is subsequently cured via exposure to or irradiation from the energy source  176 . This cycle, i.e., powder—binder/agents—cure—powder—binder/agents—cure, continues until the entire part  160  is formed layer by layer. 
     It should be understood that MJF AM can be used to form hollow structures without cupping and solid structures without warpage and/or shrinkage. Accordingly, MJF AM can be an approved AM method for forming parts with at least one surface having obfuscated anti-counterfeiting structures in the form of hollow structures (e.g., the part  50  shown in  FIG. 1B ) and/or solid structures. 
       FIG. 2C  shows a system  14  for additively manufacturing the part  160  via selective laser sintering (SLS) or direct metal laser melting (DMLM). Similar to the system  10  discussed above with respect to  FIG. 1A , the system  12  includes a first powder bed  100  on a first elevator platform  110  and a powder roller  120  configured to transfer powder from the first powder bed  100  to the second powder bed  130  on the second elevator platform  142  in the build box  140 . However, instead of a binder nozzle  150  as described above with respect to  FIG. 2A , a laser source  190  is included and configured to provide a laser beam  196  that propagates and impinges or irradiates desired or selected locations across an upper surface  132  of the powder bed  130 . In some variations laser optics  192  and a scanning mirror  194  are included and configured to direct the laser beam  196  to the desired or selected locations across the upper surface  132  of the powder bed  130 . The desired or selected locations of the upper surface  132  are sintered, or melt and solidify, to form a layer (e.g., a first layer—not labeled) of the part  160 . After the first layer is formed, the second elevator platform  142  moves downward (−z direction) and the powder roller  120  transfers powder P from the first powder bed  100  to the second powder bed  130  and spreads a thin layer of the powder P across the previously formed first layer of the part  160 . Then the laser beam  196  is directed across the powder bed  130  at desired or selected locations along or over the upper surface  132  of the powder bed  130  to form a second layer (not labeled) of the part  160 . This cycle, i.e., powder—laser—powder—laser, continues until the entire part  160  is formed layer by layer. 
     It should be understood that SLS AM and/or DMLM AM can be used to form hollow structures without cupping. However, heat input during SLS AM and/or DMLM AM and cooling after the sintering and/or melting of the metal powder inhibits these AM methods from being used to form solid structures without warpage and/or shrinkage. Accordingly, SLS AM and/or DMLM AM can be an approved AM method for forming parts with at least one surface having obfuscated anti-counterfeiting structures in the form of hollow structures (e.g., the part  50  shown in  FIG. 1B ). However, SLS AM and/or DMLM AM can be an unapproved AM method for forming solid structures. 
       FIG. 2D  shows a system  20  for additively manufacturing the part  160  via stereolithography (SLA). The system  20  includes a build tank  200  with a build platform  210  mechanically coupled to an elevator  220  configured to move the build platform  210  in a vertical direction (+/−z direction). A liquid bath  230  comprising monomers and oligomers is disposed within the build tank  200  and a light emitting device  190  (e.g., a laser source) is included and configured to provide and propagates a light  196 . In some variations laser optics  192  and a scanning mirror  194  are included and configured to direct the light  196  to desired or selected locations across an upper surface  232  of the liquid bath  230 . When the desired or selected locations of the upper surface  232  irradiated with the light  196 , the monomers and oligomers are cross-linked via photochemical processes such that a solid layer (e.g., a first layer—not labeled) of the part  160  is formed. After the first layer is formed, the elevator  220  moves the build platform  210  downward (−z direction) such that a layer of the liquid bath  230  covers the first layer and the light  196  is directed to desired or selected locations across the upper surface  232  of the liquid bath  230  to form a second layer (not labeled) of the part  160 . This cycle, i.e., liquid layer—light scan—liquid layer—light scan, continues until the entire part  160  is formed layer by layer. 
     It should be understood that SLA AM can be used to form solid structures. However, SLA AM is inhibited from being used to form hollow structures without cupping and truss structures with sagging. Accordingly, SLA AM can be an approved AM method for forming parts with at least one surface having obfuscated anti-counterfeiting structures in the form of solid structures, but SLA AM can be an unapproved AM method for forming hollow structures and truss structures. 
       FIG. 2E  shows a system  22  for additively manufacturing the part  160  via continuous liquid interface production (CLIP). The system  22  includes a build tank  200   a  with a liquid photopolymer resin  230  disposed therein and a bottom  240  with a window portion  242  that is oxygen permeable and light transparent. A light emitting device  290  (e.g., an ultraviolet light source) is included and configured to provide and propagates a light  292  (e.g., ultraviolet light). In some variations a mirror  294  is included to direct the light  292  through the window portion  242  at desired or selected locations across a lower surface  233  of the liquid photopolymer resin  230 . The light  292  results in the solidification of the photopolymer resin  230  on a build platform  210  at the desired or selected locations. Also, the build platform  210  moves upwardly (+z direction) at a desired speed such that the liquid photopolymer resin  230  flows under and maintains contact with the bottom (−z direction) of the part  160  being formed. And the oxygen permeable window portion  242  results in a persistent liquid interface between the window portion  242  and the part  160  being formed such that solidified photopolymer resin  230  does not attach to the window portion  242 . 
     It should be understood that CLIP AM can be used to form solid structures. However, CLIP AM is inhibited from being used to form hollow structures without cupping and truss structures without sagging. Accordingly, CLIP AM can be an approved AM method for forming parts with at least one surface having obfuscated anti-counterfeiting structures in the form of solid structures, but can be an unapproved AM method for forming hollow structures and truss structures. 
       FIG. 2F  shows a system  30  for additively manufacturing the part  160  via multi jetting (MJ). The system  30  includes a build platform  310  and a print head  370  with a material nozzle  372  configured to deposit liquid material  373  (e.g., liquid photopolymer resin) at desired or selected locations across the build platform  310 . The print head  370  also includes a light source  374  (e.g., an ultraviolet light source) configured to irradiate the desired or selected locations across the build platform  310  with light  375  (e.g., ultraviolet light). The light  375  cures or results in the solidification of the liquid material  373  deposited at the desired or selected locations across the build platform  310  such that a layer (e.g., a first layer—not labeled) of the part  160  is formed. After the first layer is formed, the build platform  310  moves downward (−z direction) and the material nozzle  372  deposits another layer (e.g., a second layer—not labeled) of liquid material  373  across the previously formed first layer at desired or selected locations. Then the light  375  irradiates and cures or solidifies the second layer of liquid material  373  to form a second layer (not labeled) of the part  160 . This cycle, i.e., liquid—irradiation—liquid—irradiation, continues until the entire part  160  is formed layer by layer. 
     It should be understood that MJ AM can be used to form hollow structures and solid structures. However, MJ AM is inhibited from being used to form truss structures without sagging. Accordingly, MJ AM can be an approved AM method for forming parts with at least one surface having obfuscated anti-counterfeiting structures in the form of hollow and/or solid structures, but can be an unapproved AM method for forming truss structures. 
       FIG. 2G  shows a system  32  for additively manufacturing the part  160  via fused filament fabrication (FFF). The system  32  includes the build platform  310  and an extrusion print head  350  with a heater  352  and at least one drive roller  354 . Filament  353  is fed from a spool (not shown) using the at least one drive roller  354  and the heater  352  heats the filament  353  such that liquid droplets  355  of the filament  353  are deposited at desired or selected locations across the build platform  310 , cool, and solidify such that a layer (e.g., a first layer—not labeled) of the part  160  is formed. After the first layer is formed, the build platform  310  moves downward (−z direction) and the extrusion print head  350  deposits another layer (e.g., a second layer—not labeled) of liquid droplets  355  across the previously formed layer at desired or selected locations. This cycle, i.e., liquid layer—solidification—liquid layer—solidification, continues until the entire part  160  is formed layer by layer. 
     It should be understood that FFF AM can be used to form hollow structures and solid structures. However, FFF AM is inhibited from being used to form truss structures with overhanging sections. Accordingly, FFF AM can be an approved AM method for forming parts with at least one surface having obfuscated anti-counterfeiting structures in the form of hollow and/or solid structures, but can be an unapproved AM method for forming truss structures according to the teachings of the present disclosure. 
     Referring now to  FIG. 3 , additional examples of parts that can be formed using AM methods are shown. Particularly, an exploded view of a center console assembly  40  having a lower section  400 , a main body section  410 , a storage container  420 , a coin storage part  430 , an armrest  440  and a bracket  450  is shown. In some variations, one or more of the parts of the center console assembly are formed using an approved AM method as described below. 
     For example, and with reference to  FIG. 4 , a sectional view of section A-A of the main body section  410  in  FIG. 3  is shown. The main body section  410  has a sidewall  412  with an outer surface  411  (+x direction) and an inner surface  413  (−x direction). In some variations, the outer surface  411  is an ‘A’ surface and the inner surface  413  is a ‘B’ surface. As used herein, the term “A surface” refers to a surface of a part that is visible and should be aesthetically pleasing to an individual that has purchased and/or uses the part and the term “B surface” refers to a surface of component that is not visible to an individual that has purchased and/or uses the part. 
     As shown in  FIG. 4 , a plurality of hollow structures  414  (also referred to herein simply as “hollow structures  414 ”) have been AM on the inner surface  413  of the sidewall  412  with an approved AM method such as multi jet fusion, selective laser sintering, fused filament fabrication, direct metal laser melting, binder jetting, and material jetting. Accordingly, the hollow structures  414  do not have or exhibit any cupping and/or delamination from the inner surface  413 . In addition, the hollow structures  414  each have a prohibitive shape ‘S 1 ’ and/or a prohibitive physical dimension ‘D.’ As used herein, the phrase “prohibitive shape” refers to a shape that is properly made (i.e., without defects such as cupping, warping, shrinking, among others) with an approved AM method but is improperly made with an unapproved AM method (i.e., with defects such as cupping, warping, shrinking, among others). And as used herein, the phrase “prohibitive physical dimension” refers to a physical dimension such as a length, width, depth, or angle of orientation relative to a surface, among others, of an additive manufactured structure that is properly produced (e.g., without sagging, cupping, warping, among others) with an approved AM method but is improperly made with an unapproved AM method (e.g., with sagging, cupping, warping, among others). In some variations, the prohibitive shape S 1  is a hollow sphere as shown in  FIG. 4 , while in other variations the prohibitive shape S 1  is a hollow cylinder, a hollow cone, or a hollow polyhedral (e.g., see  FIG. 1B ). And in some variations, the prohibitive physical dimension D can be an average inner dimension between about 1 millimeter (mm) and about 5 mm and/or an average wall thickness between about 1 mm and about 5 mm. 
     Referring to  FIG. 5 , a sectional view of section A-A in  FIG. 3  is shown with a plurality of solid structures  416  (also referred to herein simply as “solid structures  416 ”) AM on the inner surface  413  of the sidewall  412 . Also, the solid structures  416  do not have or exhibit warping and/or are not delaminated from the inner surface  413 . Accordingly, the solid structures  416  have been additively manufactured with an approved AM method such as multi jet fusion, fused filament fabrication, binder jetting, and material jetting, and not additively manufactured with an unapproved AM method such as selective laser sintering and direct metal laser melting. In addition, the solid structures  416  each have a prohibitive shape ‘S 2 ’ and/or at least one prohibitive physical dimension ‘D 2 ’, and/or ‘D 3 ’. In some variations, the prohibitive shape S 2  is a solid cube as shown in  FIG. 5 , while in the other variations the prohibitive shape S 2  is a solid sphere, a solid cylinder, a solid cone, or a solid polyhedral, among others. Also, in some variations the prohibitive physical dimensions D 1  and D 2  are average outer dimensions of the solid structures  416  and the prohibitive physical dimension D 3  is an average spacing between the solid structures  416 . For example, in some variations the prohibitive physical dimensions D 1  and D 2  are between about 5 mm and about 10 mm, and the prohibitive physical dimension D 3  (i.e., an average spacing between the solid structures  416 ) is between about 5 mm and about 25 mm. 
     Referring to  FIG. 6 , a sectional view of section A-A in  FIG. 3  is shown with a plurality of truss structures  418  (also referred to herein simply as “truss structures  418 ”) AM on the inner surface  413  of the sidewall  412 . Also, the truss structures  418  do not have or exhibit sagging at regions or sections  419  of the truss structures  418  that are unsupported. Accordingly, the truss structures  418  have been additively manufactured with an approved AM method such as multi jet fusion, selective laser sintering, stereolithography, binder jetting, high speed sintering, direct metal laser melting, and not additively manufactured with an unapproved AM method such as fused filament fabrication, stereolithography, and direct metal laser melting. In addition, the truss structures  418  each have a prohibitive shape ‘S 3 ’ and at least one prohibitive physical dimension ‘D 2 ’, ‘D 3 ’, and/or ‘α’. 
     In some variations, the prohibitive shape S 3  is a cross-shaped truss structure as shown in  FIG. 6 , while in the other variation the prohibitive shape S 3  is a single linear segment, two linear segments, or three linear segments attached to and extending outwardly (−x direction) from the inner surface  413 , among others. Also, in some variations the prohibitive physical dimensions D 1  and D 2  are an average height (−x direction) and an average width (y direction), and the prohibitive physical dimension D 3  is an average length of an unsupported section of the truss structures  418 . 
     In at least one variation, the prohibitive physical dimensions D 1  and D 2  are between about 1 mm and about 3 mm, the prohibitive physical dimension D 3  (i.e., the length or unsupported overhang) is between about 0.5 mm and about 1.5 mm, and the prohibitive physical dimension a (i.e., an average overhang angle between the unsupported length of the truss structure and the inner surface  413 ) is less than a predefined angle. For example, in some variations the unapproved AM method is fused filament fabrication and the prohibitive physical dimension a is any angle less than about 45°, i.e., the prohibitive physical dimension a is about 45°. Stated differently, truss structures  418  with unsupported sections  419  having an overhang angle of less than 45° are prohibitive from being formed using fused filament fabrication. In other variations the unapproved AM method is direct metal laser melting and the prohibitive physical dimension a is about 30°. And in at least one variation the unapproved AM method is stereolithography and the prohibitive physical dimension a is about 20°. 
     While  FIG. 6  shows a plurality of truss structures  418  with the prohibitive dimension a, it should be understood that other types structures can have a prohibitive physical dimension a. For example, hollow structures with at least a portion or section having an overhang angle α and solid structures with at least a portion or section having an overhang angle α are included within the teachings of the present disclosure. 
     Referring to  FIG. 7 , a sectional view of section A-A in  FIG. 3  is shown with a plurality of hollow structures  414  and a plurality of truss structures  418  AM on the inner surface  413  of the sidewall  412 . Also, the hollow structures  414  do not have or exhibit any cupping and the truss structures  418  do not have or exhibit sagging at regions or areas of the truss structures  418  that are unsupported. Accordingly, the hollow structures  414  and the truss structures  418  have been additively manufactured with an approved AM method such as multi jet fusion, selective laser sintering, direct metal laser melting, binder jetting, and not additively manufactured with unapproved AM methods such as, fused filament fabrication, direct metal laser melting, continuous liquid interface production, and stereolithography. 
     Referring now to  FIG. 8 , a flowchart for a method  60  of forming additive manufactured parts is shown. The method  60  includes AM a part with an approved AM method at  600  and AM a plurality of obfuscated anti-counterfeiting structures on at least one surface of the part using the approved AM method at  610 . Accordingly, the plurality of obfuscated anti-counterfeiting structures are properly formed on the at least one surface. In addition, forming of the plurality of obfuscated anti-counterfeiting structures on the at least one surface of the part prevents or allows detection of the part formed using an unapproved AM method. For example, inspection of the at least one surface on a part known to have (or should have) the obfuscated anti-counterfeiting structures formed thereon can provide information on the part such as whether or not the obfuscated anti-counterfeiting structures are present, and if present, have they been properly formed. If the obfuscated anti-counterfeiting structures are not present, then it can be determined that the part has not been made by the OEM or a licensed, approved, and/or designated contractor or supplier (i.e., the part is a counterfeit part). In the alternative, if the obfuscated anti-counterfeiting structures are present, then it can be determined whether or not the obfuscated anti-counterfeiting structures, and thus the part, have been formed with an approved AM method. And if the obfuscated anti-counterfeiting structures have been formed with an approved AM method (e.g., no defects present), then it can be determined that the part has been made by the OEM or a licensed, approved, and/or designated contractor or supplier. In the alternative, if the obfuscated anti-counterfeiting structures have not been formed with an approved AM method (e.g., defects are present), then it can be determined that the part has not been made by the OEM or a licensed, approved, and/or designated contractor or supplier (i.e., the part is a counterfeit part). 
     Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above or below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
     Unless otherwise expressly indicated herein, all numerical values indicating mechanical/thermal properties, compositional percentages, dimensions and/or tolerances, or other characteristics are to be understood as modified by the word “about” or “approximately” in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice, material, manufacturing, and assembly tolerances, and testing capability. 
     As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.” 
     The terminology used herein is for the purpose of describing particular example forms only and is not intended to be limiting. The singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed. 
     The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.