Abstract:
Apparatuses and systems that enable selective removal of protective coatings from substrates are disclosed. Such a material removal system may use pressurized solid carbon dioxide (CO2) (i.e., dry ice) to remove a selected portion of a protective coating from a substrate. The material removal system may include one or more templates that provide selectivity in removing protective coatings from one or more substrates, fixtures for holding one or more substrates in place while material removal processes occur and apparatuses for positioning one or more substrates at desired locations in material removal systems.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    Claims to the benefit of the Aug. 29, 2014, filing date of U.S. Provisional Patent Application 62/044,013, titled MULTI-AXIS PLATFORM FOR USE WITH A MATERIAL REMOVAL APPARATUS (“the &#39;013 Provisional Application”), and the Aug. 29, 2014, filing date of U.S. Provisional Patent Application 62/044,097, titled HOLD-DOWN FIXTURE FOR USE IN REMOVING A PROTECTIVE COATING FROM SELECTED AREAS OF A SUBSTRATE (“the &#39;097 Provisional Application”), are hereby made pursuant to 35 U.S.C. §119(e). The entire disclosures of the &#39;013 Provisional Application and the &#39;097 Provisional Application are hereby incorporated by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    This disclosure relates generally to apparatuses and systems that enable selective removal of protective coatings from substrates. In some embodiments, the material removal apparatuses or systems may comprise dry ice blasting systems, which are direct pressurized solid carbon dioxide (CO 2 ) (i.e., dry ice) toward a protective coating on a substrate. More specifically, this disclosure relates to apparatuses that are configured to facilitate the removal of selected portions of protective coatings from one or more substrates, including dry ice blasting systems, templates that provide selectivity in removing protective coatings from one or more substrates, fixtures for holding one or more substrates in place while material removal processes occur and apparatuses for positioning one or more substrates at desired locations in material removal systems. 
       SUMMARY 
       [0003]    Material removal apparatuses and systems may be used to remove portions of a material from a substrate. Some material removal apparatuses and systems may be configured to selectively remove material from substrates. In a particular implementation, material removal apparatuses and systems may be used to selectively remove portions of protective coatings (e.g., moisture-resistant coatings, such as parylene coatings) from substrates, including, but not limited to, subassemblies and assemblies of electronic devices (e.g., portable electronic devices, wearable electronic devices and other wearable devices, electronic devices that are expected to be exposed to the elements and medical devices). So-called “dry ice blasting” processes, equipment and systems have been found to be particularly effective for selectively removing protective coatings from substrates. 
         [0004]    Dry ice blasting may be used to remove a protective coating without leaving any chemical residue, as dry ice sublimates (i.e., vaporizes from a solid to a gas) at room temperature, and without generating any secondary waste material. Dry ice blasting systems accelerate particles or pellets of dry ice with pressurized air or a pressurized gas. A dry ice blasting system may pressurize the dry ice and direct it toward a substrate as a stream or jet or as a curtain or sheet. The location of the stream or jet or the curtain or sheet may remain stationary as the dry ice blasting equipment operates. In embodiments where the impact area of the dry ice will not simultaneously cover all of the areas of a substrate from which one or more portions of a protective coating is to be removed, a nozzle from which the dry ice is ejected and/or the substrate may be moved laterally (i.e., along and x-axis and a y-axis) to enable the dry ice to contact all of the areas of a protective coating that are to be removed. In some embodiments, it may also be desirable to select the spacing between the nozzle and the substrate (i.e., along a z-axis). 
         [0005]    In one aspect, this disclosure relates to dry ice blasting systems with chambers that are configured to receive one or more substrates and within which dry ice, under pressure, may be directed toward the substrate(s). 
         [0006]    In another aspect, platforms are disclosed that are configured to be placed in and, optionally, removed from the chambers of dry ice blasting systems and to move one or more substrates relative to pressurized dry ice. Such a platform may include a support and an actuator. The support may be configured to receive and, optionally, engage one or more substrates, and to hold each substrate supported thereby in place as pressurized dry ice is directed onto that substrate. The actuator may be configured to move the support along at least one axis relative to (e.g., under) the pressurized dry ice. In some embodiments, the actuator may be configured to move the support and any substrates carried thereby along two or more axes, such as the x-axis and the y-axis of a chamber of dry ice blasting equipment. The actuator may also be configured to move the support and any substrates carried thereby along a z-axis (i.e., toward and away from a head from which the pressurized dry ice is expelled). 
         [0007]    As an alternative to the use of a movable platform in a chamber of a dry ice blasting system, the nozzle(s) of the dry ice blasting system, from which dry ice is ejected, may be configured to move in multiple axes (e.g., x-axis, y-axis and/or z-axis) relative to a fixed location, or platen of the dry ice blasting system, which platen is configured to hold one or more substrates from which a protective coating may be removed. 
         [0008]    In some embodiments, a movable nozzle and a movable platform may be used in conjunction with one another to hold and selectively remove protective coatings from one or more substrates. Both the nozzle and the platform may move in one or more common directions (e.g., x-axis, y-axis and/or z-axis) or the nozzle may move in some directions (e.g., z-axis) while the platform moves in different directions (e.g., x-axis and y-axis). 
         [0009]    In another aspect, this disclosure relates to templates that may be used to facilitate the removal of portions of a protective coating from selected locations of a substrate. Such a template may be configured for assembly with at least one surface or side of a substrate, such as an electronic device (e.g., an electronic component, an electronic subassembly or an electronic assembly). The template may seal against the surface against which it is assembled, and each portion of the protective coating that is to be removed from the substrate may be exposed through a corresponding aperture of the template. 
         [0010]    Fixtures for holding one or more substrates in place during dry ice blasting or other material removal processes are also disclosed. Such a fixture may be configured to receive one or more substrates and to position the one or more substrates in desired orientations. The fixture and the substrate(s) may then be received by a platen or a support plate of a material removal system and, along with the platen or the support plate, position each substrate in a desired orientation relative to a material removal component of the material removal system (e.g., a nozzle of a dry ice blasting system). As an alternative to directly receiving a substrate, each receptacle of a fixture may be configured to receive one or more templates that have been assembled with a substrate. 
         [0011]    Another aspect of this disclosure relates to methods for removing protective coatings or other materials from substrates using any combination of apparatuses of this disclosure. Such a method may include assembling at least one template with at least one substrate, placing each substrate on a platen or a support plate, securing each substrate in place on the platen or the support plate, adjusting positions of a nozzle of a dry ice blasting system and each substrate relative to one another and/or directing pressurized dry ice toward each substrate. The template and/or selective movement of the platen/support plate and/or the nozzle may sequentially expose a plurality of different areas of a protective coating on a substrate to the pressurized dry ice and enable the pressurized dry ice to remove selected portions of the protective coating from each substrate. 
         [0012]    Other aspects, as well as features and advantages, of the disclosed subject matter will be apparent to those of ordinary skill in the art through consideration of the ensuing description, the accompanying drawings and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    In the drawings: 
           [0014]      FIG. 1  illustrates an embodiment of a dry ice blasting system; 
           [0015]      FIG. 2  depicts an embodiment of a movable platform that may be used with various embodiments of dry ice blasting systems, including, but not limited to, the embodiment depicted by  FIG. 1 ; 
           [0016]      FIG. 3  provides an exploded view of the embodiment of movable platform shown in  FIG. 2 ; 
           [0017]      FIGS. 4A-4C  show an embodiment of a template that may be used to hold an embodiment of a substrate and to expose selected regions on at least one side of the substrate to dry ice blasting processes, such as those effected by way of an embodiment of a dry ice blasting system according to this disclosure; 
           [0018]      FIGS. 5A and 5B  show an embodiment of a substrate from which selected portions of a protective coating have been removed using a dry ice blasting process and the embodiment of template shown in  FIGS. 4A-4C ; and 
           [0019]      FIG. 6  provides an assembly view another embodiment of a fixture that may be used in dry ice blasting processes, including those carried out by various embodiments of dry ice blasting systems, the embodiment of fixture depicted by  FIG. 5  being configured to receive and organize a plurality of templates. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]      FIG. 1  illustrates an embodiment of a dry ice blasting system  1 . The dry ice blasting system  1  may be used to selectively remove portions of a protective coating (e.g., a parylene coating or a coating that includes multiple layers formed by atomic layer deposition (ALD) processes) from a substrate (e.g., an electronic device assembly). When dry ice blasting processes are used, removal of selected portions of a protective coating may occur with no chemical residue, as dry ice sublimates to gaseous carbon dioxide (CO 2 ) at room temperature, and without generating any secondary waste material other than the material that has been removed from the substrate, as dry ice and CO 2  are generally considered to be non-toxic. 
         [0021]    In the depicted embodiment, the dry ice blasting system  1  includes dry ice supply  2 , a pressurization component  3 , a chamber  4 , a nozzle  5  and a platen  7 . The pressurization component  3  is associated with the dry ice supply  2  in a manner that retrieves dry ice from the dry ice supply  2  and conveys the dry ice under pressure to the nozzle  5 , which is located within the chamber  4 . At the nozzle  5 , the pressurized dry ice is directed toward the platen  7  and any substrates  60  that are carried by the platen  7 . 
         [0022]    The dry ice supply  2  may store dry ice in any suitable form, for example, as a block, as pellets or as particles. The pressurization component  3 , which may be part of the dry ice supply  2  or associated with the dry ice supply  2 , may employ pressurized air or a pressurized gas to accelerate the particles or pellets of dry ice. The pressurization component  3  may be configured to operate for a sufficient duration of time to remove a desired amount of protective material of the protective coating from a substrate (e.g., partially remove the protective material to thin the protective coating at one or more selected regions and/or completely remove the protective material from one or more selected regions of the protective coating). 
         [0023]    The nozzle  5  of the dry ice blasting system  1  may be configured to direct the dry ice toward the platen  7  or toward a substrate carried by the platen  7 , and to define the shape of an area the dry ice impacts on the platen  7  or on a substrate (not shown) carried by the platen  7 . In some embodiments, the nozzle  5  may be configured to emit a narrow stream, or jet, of dry ice (e.g., a stream having a width of about 3 mm or less, a stream having a width of about 2 mm or less, a stream having a width of about 1 mm or less or a stream having a width of about 0.5 mm less). The stream may have any desired cross-sectional shape and, thus, impact an area having any desired shape (e.g., circular, oval, rectangular, square or triangular). In other embodiments, the nozzle  5  may be configured to eject a curtain or sheet of dry ice. In a specific embodiment, the fan nozzle  5  may comprise a fan nozzle with a 1.6 mm×20 mm opening. Such a curtain or sheet of dry ice may have any desired width (e.g., about 2 mm wide or less, about 1.5 mm wide or less, about 1 mm wide or less or about 0.5 mm wide or less) and any desired length (e.g., about 5 mm, about 1 cm, about 2 cm, about 5 cm or about 10 cm). 
         [0024]    The dry ice blasting system  1  may include a gantry  6  that carries the nozzle  5  and determines a lateral (i.e., x-axis, y-axis, or X-Y) and/or vertical (i.e., z-axis, or Z) position of the nozzle  5  within the chamber  4  and over the platen  7 . Any suitable configuration of gantry  6  may be employed in the dry ice blasting system  1 . 
         [0025]    Optionally, the dry ice blasting system  1  may include an exhaust system  8 . The exhaust system  8  may be associated with an interior of the chamber  4  in a manner that enables carbon dioxide (CO 2 ) to be drawn from the interior of the chamber  4  and conveyed to another location (e.g., to the atmosphere or to a storage/waste container). 
         [0026]    The platen  7  may include positioning elements that ensure that a particular substrate (e.g., a subassembly of an electronic device) is positioned in a desired orientation and/or that secure the substrate in the desired orientation. As an alternative to including such positioning elements, the platen  7  may be configured to receive separate positioning elements. 
         [0027]    The platen  7  of a dry ice blasting system  1  may be configured to be move in a variety of directions within the interior of the chamber  4 . Without limitation, the platen  7  may be configured to be raised and lowered (i.e., to move along a z-axis). The platen  7  may be configured to move laterally, for example, from side to side (i.e., along an x-axis) and/or from front to back (i.e., along a y-axis). Alternatively, a position of the platen  7  within the chamber  4  of a dry ice blasting system  1  may be fixed. 
         [0028]    A platen  7  of a dry ice blasting system  1  may be configured to receive a moveable platform  10 , such as that depicted by  FIG. 2  (in assembled form) and  FIG. 3  (in exploded form). The movable platform  10  may be secured to the platen  7  in any suitable manner (e.g., with features that mutually engage features of the platen  7 , with intermediate engagement features that are configured to be assembled between the platen  7  and the moveable platform  10  or by way of an interference fit between corresponding features of the platen  7  and the moveable platform  10 ). A moveable platform  10  may be configured to enable movement of one or more substrates laterally (i.e., side-to-side, or along an x-axis, and front-to-back, or along a y-axis). A movable platform  10  may also be configured to move one or more substrates vertically (i.e., up and down, or along a z-axis). 
         [0029]    The embodiment of movable platform  10  depicted by  FIGS. 2 and 3  includes a base plate  12 , a z-movement system  20 , an x-movement system  30 , a y-movement system  40  and a support plate  46 . Such a moveable platform  10  may enable movement of a substrate within a dry ice blasting system  1  ( FIG. 1 ) (e.g., a manually operable dry ice blasting system  1  or an automated dry ice blasting system  1 ) or within any other embodiment of material removal system to enable removal of a material, such as a protective coating, from selected locations of the substrate. 
         [0030]    The base plate  12  of the movable platform  10  may be configured for placement on the platen  7  ( FIG. 1 ) of a dry ice blasting system  1  ( FIG. 1 ). The base plate  12  and the platen  7  may include complementarily configured features, which may ensure that the base plate  12  is properly positioned, or aligned, on the platen  7  and/or that the base plate  12  is secured to the platen  7 . In some embodiments, these complementarily configured features may be carried by and/or formed in surfaces of the base plate  12  and the platen  7  that are configured to oppose, or face, one another. 
         [0031]    The base plate  12  may include one or more handles  14 , with two handles  14  being shown in the embodiment of dry ice blasting system  1  depicted by  FIGS. 2 and 3 ). The handles  14  may facilitate placement of the movable platform  10  within the chamber  4  ( FIG. 1 ) of a dry ice blasting system  1  ( FIG. 1 ) and on the platen  7  ( FIG. 1 ) of the dry ice blasting system  1 , as well as removal of the movable platform  10  from the platen  7  and the chamber  4 . 
         [0032]    In embodiments where the movable platform  10  includes a z-movement system  20 , the z-movement system  20  may be secured to the base plate  12  of the movable platform  10 . While the z-movement system  20  may have any of a variety of suitable configurations,  FIGS. 2 and 3  depict an embodiment in which the z-axis system  20  includes a stand  22  and a support plate  26 . The stand  22  includes at least one actuator  24  (e.g., a manually operable dial or one or more suitable motors and associated controls) that is configured to raise and lower the support plate  26 . 
         [0033]    In embodiments where the movable platform  10  includes an x-movement system  30 , the x-movement system  30  may be secured to the support plate  26  of a z-movement system  20  or, if the movable platform  10  does not include a z-movement system  20 , to the base plate  12  of the moveable platform  10 . An x-movement system  30  may include one or more elements that facilitate side-to-side movement, such as the rails  32  and sliders  34  depicted by  FIGS. 2 and 3 . Each rail  32  may be oriented to extend from a location on one side of the base plate  12  and, thus, of the movable platform  10  to a location on an opposite side of the base plate  12  and the moveable platform  10 . Each slider  34  may be configured to engage a rail  32  and to move along a length of the rail  32 , in some embodiments with little or no friction. The sliders  34  may be secured to a bottom surface of a support plate  36  of the x-movement system  30  to enable the support plate  36  to move along the lengths of the rails  32  and, thus, from side-to-side relative to the base plate  12  and the remainder of the movable platform  10 . 
         [0034]    In embodiments where the movable platform  10  includes a y-movement system  40 , as illustrated, the y-movement system  40  may be secured to the support plate  36  of an x-movement system  30 . If the movable platform  10  lacks an x-movement system  30  but includes a z-movement system  20 , the y-movement system  40  may be secured to the support plate  26  of the z-movement system  20 . If the movable platform  10  lacks both an x-movement system  30  and a z-movement system  20 , the y-movement system  40  may be secured to the base plate  12  of the movable platform  10 . In any of these embodiments, the y-movement system  40  may include one or more elements that facilitate front-to-back movement, such as the rails  42  and sliders  44  depicted by  FIGS. 2 and 3 . Each rail  42  may be oriented to extend from a location at or near a front the base plate  12  and, thus, of the movable platform  10  to a location at or near a rear of the base plate  12  and the moveable platform  10 . Each slider  44  may be configured to engage a rail  42  and to move along a length of the rail  42 , in some embodiments with little or no friction. The sliders  44  may be secured to a bottom surface of a support plate  46  of the y-movement system  40  to enable the support plate  46  to move along the lengths of the rails  42  and, thus, from front-to-back relative to the base plate  12  and the remainder of the movable platform  10 . 
         [0035]    The uppermost support plate  26 ,  36 ,  46  of the movable platform  10  may be configured to receive one or more substrates (not shown) that are to be processed by a dry ice blasting system  1  ( FIG. 1 ). In the depicted embodiment, support plate  46  is the uppermost support plate. In some embodiments, the uppermost support plate  46  may include or be configured to receive one or more elements that position each substrate in a desired orientation and/or secure each substrate to an upper surface of the support plate  46 . 
         [0036]    As illustrated by  FIGS. 2 and 3 , in some embodiments, a movable platform  10  may include one or more actuation elements  50 . Each actuation element  50  may be configured to cause the uppermost support plate (i.e., support plate  46  in the depicted embodiment) to move in one or more desired directions. In the illustrated embodiment, each actuation element  50  may comprise a handle, which may be manually grasped to enable manipulation of the lateral (i.e., x-axis and/or y-axis) positions of the support plate  46  and any substrates carried by the support plate  46 . In other embodiments, the actuation element  50  may enable automated movement of the support plate  46  (e.g., by way of one or more motors and controls associated with the motor(s)). 
         [0037]    In addition to showing the primary elements of an embodiment of a movable platform,  FIG. 3  shows a specific, but non-limiting, embodiment in which those elements may be secured to one another. Specifically,  FIG. 3  illustrates the use of screws to secure the various elements to one another in intended arrangements. Other options for securing various elements of a moveable platform  10  to one another include the use of rivets, welds, brazing, adhesive materials, press fits, interferences fits and the like. 
         [0038]    In addition to enabling movement of one or more substrates (not shown) within the chamber  4  ( FIG. 1 ) of a dry ice blasting system  1  ( FIG. 1 ), the movable platform  10  may simplify the process of arranging the one or more substrates over the platen  7  of a dry ice blasting system  1 . Since the movable platform  10  is configured to be removed from the chamber  4  ( FIG. 1 ) of the dry ice blasting system  1 , one or more substrates may be placed on an uppermost support plate  46  of the movable platform  10  without the impediments that would otherwise be presented by various features defining the chamber  4  of the dry ice blasting system  1 . With each substrate in place upon the uppermost support plate  46 , the movable platform  10  may then be placed into the chamber  4 , and the substrate(s) may then be subjected to dry ice blasting. 
         [0039]    As an alternative to placing one or more substrates directly on the platen  7  ( FIG. 1 ) of a dry ice blasting system  1  ( FIG. 1 ) or directly on the uppermost support plate  46 , of a movable platform  10  ( FIGS. 2 and 3 ) that is configured to be introduced into the chamber  4  ( FIG. 1 ) of a dry ice blasting system  1  and onto the platen  7  of the dry ice blasting system  1 , the one or more substrates  60  may be secured to a template  100 , as illustrated by  FIGS. 4A-4C . The template  100  may then be secured to the platen  7  or the uppermost support plate  46 . 
         [0040]      FIGS. 4A-4C  illustrate an embodiment of a template  100  that has been assembled with a substrate  60 . The substrate  60  may comprise a subassembly of an electronic device or an assembly of an electronic device, both of which may be referred to herein as an “electronic device assembly.” In the illustrated embodiment, the substrate  60  comprises a printed circuit board (PCB), although a template  100  according to this disclosure may be configured to receive any of a variety of different types of electronic devices (e.g., electronic device assemblies that include flexible circuit boards (FCBs), frames or housing elements), as well as a variety of other types of substrates  60 . 
         [0041]    The material(s) from which the elements  102  and  106  of a template  100  are made may withstand material removal processes without suffering from undesired degradation. Without limitation, the elements  102  and  106  may be made from a suitable metal (e.g., aluminum, stainless steel or steel), a resin or a rigid thermoplastic material. While the elements  102  and  106  may have any suitable configuration, as shown in  FIGS. 4A-4C , they may be generally flat. 
         [0042]    When the elements  102  and  106  of such an embodiment of template  100  are assembled with a substrate and the elements  102  and  106  are assembled with each other, the substrate  60  may be sandwiched and held in place between the elements  102  and  106 . The elements  102  and  106  may be secured to each other in any suitable manner. Without limitation, corresponding features of the elements  102  and  106  may engage each other in an interference fit or a snap-fit as the elements  102  and  106  are properly assembled with each other. 
         [0043]    While the template  100  shown in  FIGS. 4A-4C  includes two elements  102  and  106 —a top element and a bottom element, templates that only include one element (e.g., a top element or a bottom element) are also within the scope of this disclosure. As shown by  FIG. 4A , a first element  102  of the template  100  is configured for assembly over a first side  64  of a substrate  60  and a second element  106  of the template  100  is configured to be assembled over a second side  66  of the substrate  60 . Inner surfaces  105  and  109  of the elements  102  and  106  of the template  100  are respectively configured to be placed against the first side  64  and the second side  66  of the substrate  60 . 
         [0044]      FIGS. 4B and 4C  respectively show views of the outer surfaces  103  and  107  of the elements  102  and  106 , to which apertures  104  and  108  open. The apertures  104  and  108  are configured to be positioned over parts of a protective coating that are to be removed from the substrate  60 . Thus, as dry ice is directed into one or more of the apertures  104 ,  108 , protective material may be removed from portions of the protective coating that are exposed through each aperture  104 ,  108 . Accordingly, a template  100  that includes elements  102  and  106  with apertures  104  and  108 , respectively, that are configured to be positioned over opposite sides  64  and  66  of a substrate  60  may be configured to be positioned in an upright orientation and an inverted orientation to enable the selective removal of portions of a protective coating from each side  64 ,  66  of the substrate  60 . 
         [0045]    In some embodiments, the inner surfaces  105  and  109  of the elements  102  and  106  of the template  100  may be at least partially lined with a material that will seal against the sides  64  and  66  of the substrate  60 . A seal may also protect the substrate  60  from damage that might otherwise be cause by vibration of the template  100  and/or the substrate  60  as material is removed from the substrate  60 . In more specific embodiments, the seal(s) on the inner surface  105 ,  109  of an element  102 ,  106  of the template  100  may comprise a foam material (e.g., polystyrene foam or polyurethane foam) carried by the inner surface  105 ,  109 . The seal(s) may prevent movement of each substrate  60  relative to an element  102 ,  106  of the template  100 , prevent dry ice from reaching one or more locations on a side  64 ,  66  of the substrate  60  on which a protective coating is to remain and/or prevent damage to the substrate  60  or to regions of a protective coating that are to remain intact on the substrate  60 . 
         [0046]    In  FIGS. 5A and 5B , the substrate  60  is shown after a portion of a protective coating  74 ,  76  has been removed from each side  64 ,  66  of the substrate  60 . More specifically,  FIGS. 5A and 5B  show that features and/or components  75   a,    75   b,  etc.;  77   a,    77   b,  etc., of the substrate  60  have been exposed through the protective coating  74 ,  76  on each side of the substrate  60 . As indicated previously herein, the depicted embodiment of substrate  60  comprises a flexible circuit board. As shown in  FIG. 5A , on side  64 , portions of a protective coating  74  that were located over a ground trace  75   a,  a board-to-board connector  75   b  (e.g., a plug-in type connector or a zero insertion force (ZIF) connector) and a wireless connector  75   c  (e.g., a radiofrequency connector or a BLUETOOTH® connector) have been removed to expose these features and/or components. In  FIG. 5B , which shows side  66  of the substrate  60 , a two board-to-board connectors  77   a  and  77   b  and a wireless connector  77   c  have been exposed through protective coating  76 . 
         [0047]    Turning now to  FIG. 6 , an embodiment of a fixture  120  is depicted. Fixture  120  provides a plurality of receptacles  130   a,    130   b,  etc., for receiving a plurality of substrates  60  and, optionally, for receiving a plurality of substrate  60 -template  100  assemblies (see, e.g.,  FIGS. 4A-C ). In some embodiments, the fixture  120  includes a pair of elements  122  and  126  that, together, define the plurality of receptacles  130   a,    130   b,  etc., each of which is configured to receive a substrate  60  and/or a substrate  60 -template  100  assembly. 
         [0048]    The elements  122  and  126  of a fixture  120  may be made from any suitable metal. Without limitation, metal (e.g., aluminum, stainless steel or steel), a resin and/or a rigid thermoplastic material may be used to form the elements  122  and  126  of the fixture  120 . 
         [0049]    In some embodiments, such as those depicted by  FIG. 6 , each receptacle  130   a,    130   b  may be associated with a one or more exposure apertures  124   a  and  128   a,    124   b  and  128   b,  etc., with dimensions that may expose a majority of a corresponding side of a substrate  60  assembled with that receptacle  130   a,    130   b.  Such an embodiment of fixture  120  may be configured for use with separate templates  100  ( FIGS. 4A-4C ) that, in turn, are configured to be positioned adjacent to at least one side  64 ,  66  of a substrate  60 . More specifically, each receptacle  130   a,    130   b  of the fixture  120  may be configured to receive a template  100 . Even more specifically, each receptacle  130   a,    130   b  of the fixture  120  may be configured to receive any of a variety of templates  100  with standardized outer dimensions. Such a configuration may enable different templates  100  that are configured for use with different substrates  60  (including, but not limited to, substrates  60  with different shapes and/or dimensions) to be used with a single fixture  120 . Such a configuration may also enable templates  100  with different arrangements of apertures  104 ,  108  ( FIGS. 4A-4C ) to be used with the same fixture  120 . 
         [0050]    When the elements  122  and  126  of a fixture  120  are assembled with one another, they may be secured to each other in any suitable manner. Without limitation, corresponding features of the elements  122  and  126  may engage each other (e.g., in an interference fit or a snap fit). Alternatively, the elements  122  and  126  may be secured to one another with suitable coupling elements, such as clamps, bolts (and, optionally, nuts) and the like. 
         [0051]    In embodiments where a fixture  120  is configured to hold substrates  60  that have been assembled with complementary templates  100  ( FIGS. 4A-4C ), as the elements  122  and  126  of the fixture  120  are assembled with one another and secured in the assembled relationship, seals on the inner surfaces  105  and  109  ( FIGS. 4A-4C ) of the elements  102  and  106  ( FIGS. 4A-4C ) of the template  100  may be forced against adjacent sides  64  and  66  ( FIG. 4A ), respectively, of the substrate  60 , forming a tight seal against the sides  64  and  66  of the substrate  60 . 
         [0052]    Although the preceding disclosure provides many specifics, these should not be construed as limiting the scope of any of the ensuing claims. Other embodiments may be devised which do not depart from the scopes of the claims. Features from different embodiments may be employed in combination. The scope of each claim is, therefore, indicated and limited only by its plain language and the full scope of available legal equivalents to its elements.