Patent Publication Number: US-2022228957-A1

Title: System, Method, and Apparatus for Automating Specimen Testing

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of, and priority to, U.S. Provisional Patent Application No. 63/140,046, entitled “System, Method, And Apparatus For Automating Specimen Testing,” filed Jan. 21, 2021, the entire contents of which are hereby incorporated by reference. 
    
    
     FIELD 
     The present disclosure is directed to specimen testing and, more particularly, to a system, method, and apparatus for automating residual seal force testing and/or compression friction measurement testing. 
     BACKGROUND 
     Since the early part of the 20 th  century, containers (e.g., bottles, vials, etc.) with elastomeric closures and, in some cases, crimped caps have been a primary packaging system for parenteral (i.e., injectable) medicines. Parenteral products contained in such container package systems require a robust seal at the interface between the glass container and the elastomeric stopper to prevent contamination and product leakage. While the seal is established in the manufacturing process, it must withstand a variety of handling, processing, and storage conditions prior to use. 
     In some examples, container seal is composed of three major components—the glass container, an elastomeric closure (e.g., a rubber stopper), and a cap that secures the rubber stopper in the container, such as an aluminum cap. When a metal cap is used, typically an aluminum or aluminum alloy, the cap must be crimped onto the stopped container with a compressive force that will ensure sufficient mating of the container and elastomeric closure. In other examples, the cap is removed for other testing. Closure variables that affect the container seals include dimensional characteristics and tolerances, along with the mechanical properties of the closure components, including modulus, hardness, and compression set. 
     Manufacturers of parenteral containers are required to employ a quantitative method for measuring the force a closure exerts against the container after the initial seal is made and throughout the shelf life of the product. In the case of a closure that uses a metal cap, this force measured using a residual seal force (“RSF”) test, while a compression friction (“CF”) measurement test is used evaluate a glass container that is sealed using a plunger. A CF measurement test is sometimes called a glide test. While existing RSF and CF testers can measure the RSF and CF, such testing can be time consuming, tedious, and labor intensive. Therefore, it is desirable to provide a more accurate, more tolerant, and/or automated system, method, and apparatus for RSF and/or CF testing. 
     SUMMARY 
     Systems, methods, and apparatuses for testing are disclosed, substantially as illustrated by and described in connection with at least one of the figures. More particularly, systems, methods, and apparatuses are disclosed for determining the residual seal force and/or compression friction measurement for containers, particularly containers for parenteral pharmaceutical products. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other objects, features, and advantages of the devices, systems, and methods described herein will be apparent from the following description of particular embodiments thereof, as illustrated in the accompanying figures; where like or similar reference numbers refer to like or similar structures. The figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the devices, systems, and methods described herein. 
         FIG. 1 a    illustrates a perspective view of an example testing system in accordance with aspects of this disclosure. 
         FIG. 1 b    illustrates a perspective view of the example testing system of  FIG. 1 a    with portions removed to better illustrate the load string. 
         FIG. 2 a    illustrates a plan cross-sectional view of a first example test head in accordance with aspects of this disclosure. 
         FIGS. 2 b  and 2 c    illustrate plan cross-sectional views of the first example test head of  FIG. 2 a    in contact with a specimen. 
         FIG. 2 d    illustrates a plan cross-sectional view of the first example test head with a concave region at the point of contact. 
         FIG. 3 a    illustrates a plan cross-sectional view of a second example test head in accordance with aspects of this disclosure. 
         FIGS. 3 b  and 3 c    illustrate plan cross-sectional views of the second example test head of  FIG. 3 a    in contact with a specimen. 
         FIG. 4 a    illustrates a perspective view a third example test head in accordance with aspects of this disclosure. 
         FIG. 4 b    illustrates a plan cross-sectional views of the third example test head taken along section A-A of  FIG. 4   a.    
         FIG. 5  is a flowchart representative of an example method for operating the example testing system. 
     
    
    
     DETAILED DESCRIPTION 
     References to items in the singular should be understood to include items in the plural, and vice versa, unless explicitly stated otherwise or clear from the text. Grammatical conjunctions are intended to express any and all disjunctive and conjunctive combinations of conjoined clauses, sentences, words, and the like, unless otherwise stated or clear from the context. Recitation of ranges of values herein are not intended to be limiting, referring instead individually to any and all values falling within the range, unless otherwise indicated herein, and each separate value within such a range is incorporated into the specification as if it were individually recited herein. In the following description, it is understood that terms such as “first,” “second,” “top,” “bottom,” “side,” “front,” “back,” and the like are words of convenience and are not to be construed as limiting terms. For example, while in some examples a first side is located adjacent or near a second side, the terms “first side” and “second side” do not imply any specific order in which the sides are ordered. 
     As used herein, the terms “about,” “approximately,” “substantially,” or the like, when accompanying a numerical value, are to be construed as indicating a deviation as would be appreciated by one of ordinary skill in the art to operate satisfactorily for an intended purpose. Ranges of values and/or numeric values are provided herein as examples only, and do not constitute a limitation on the scope of the described embodiments. The use of any and all examples, or exemplary language (“e.g.,” “such as,” or the like) provided herein, is intended merely to better illuminate the embodiments and does not pose a limitation on the scope of the embodiments. The terms “e.g.,” and “for example” set off lists of one or more non-limiting examples, instances, or illustrations. No language in the specification should be construed as indicating any unclaimed element as essential to the practice of the embodiments. 
     As used herein, the term “and/or” means any one or more of the items in the list joined by “and/or.” As an example, “x and/or y” means any element of the three-element set {(x), (y), (x, y)}. In other words, “x and/or y” means “one or both of x and y”. As another example, “x, y, and/or z” means any element of the seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}. In other words, “x, y, and/or z” means “one or more of x, y, and z.” 
     As used herein, the terms “circuit” and “circuitry” includes any analog and/or digital components, power and/or control elements, such as a microprocessor, digital signal processor (DSP), software, and the like, discrete and/or integrated components, or portions and/or combinations thereof. 
     As used herein, the terms “compression rod” and “compression pin” as used herein, each mean a rigid structure configured to impart a compressive force upon a specimen positioned in a testing system. In the case of a CF test, for example, the compression pin can be used to compress the elastomeric closure within a rigidly-supported parenteral container, such as a vial. 
     As used herein, the terms “drivingly coupled,” “drivingly coupled to,” and “drivingly coupled with” as used herein, each mean a mechanical connection that enables a driving part, device, apparatus, or component to transfer a mechanical force to a driven part, device, apparatus, or component. 
     As used herein, the term “processor” means processing devices, apparatuses, programs, circuits, components, systems, and subsystems, whether implemented in hardware, tangibly embodied software, or both, and whether or not it is programmable. The term “processor” as used herein includes, but is not limited to, one or more computing devices, hardwired circuits, signal-modifying devices and systems, devices and machines for controlling systems, central processing units, programmable devices and systems, field-programmable gate arrays, application-specific integrated circuits, systems on a chip, systems comprising discrete elements and/or circuits, state machines, virtual machines, data processors, processing facilities, and combinations of any of the foregoing. The processor may be, for example, any type of general purpose microprocessor or microcontroller, a digital signal processing (DSP) processor, an application-specific integrated circuit (ASIC). The processor may be coupled to, or integrated with a memory device. 
     As used herein, the term “memory” and/or “memory device” means computer hardware or circuitry to store information for use by a processor and/or other digital device. The memory and/or memory device can be any suitable type of computer memory or any other type of electronic storage medium, such as, for example, read-only memory (ROM), random access memory (RAM), cache memory, compact disc read-only memory (CDROM), electro-optical memory, magneto-optical memory, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically-erasable programmable read-only memory (EEPROM), flash memory, solid state storage, a computer-readable medium, or the like. 
     A quantitative method for measuring a closure force exerted against a container after sealing can be performed using a constant rate of compression testing machine. By exerting a slow, constant rate of compression on a sealed container, a stress vs. time curve can be generated to determine a residual seal force (RSF) measurement of a given closure seal in a specimen. The RSF measurement can be determined for a variety of containers with various closure sizes and shapes. RSF measurements, for example, can be used to indicate the security of the container&#39;s closure as part of a manufacturer&#39;s quality control. The initial force with which the closure compresses the container is a function of the vertical and horizontal crimping forces applied during application (e.g., crimping) of the aluminum cap; however, due to the viscoelastic relaxation behavior of rubber, the force of the closure pressing against the containers decays as a function of time, elastomer composition, and as a result of various processing procedures. In another example, a compression friction (CF) measurement test can be performed using the compression testing machine to qualify a glass container that is sealed using an elastomeric closure (e.g., a plunger). A CF measurement test is sometimes referred to as a glide test. 
     To evaluate a seal tightness, manufacturers sometimes use manual testing systems as part of their quality control processes to measure the RSF or the CF of a parenteral package created during a container-sealing process. Typically, manufacturers test small batches or volumes (e.g., lot or line samples) as part of its quality control efforts. Because RSF and CF testing is considered destructive testing (i.e., the product is no longer saleable), manufacturers may test only between 0.5% and 1.25% of the production, or about 0.66% of the production. Further, operators, who are already busy with other production-related tasks, are only permitted a limited amount of time to perform each test (e.g., about 1-2 minutes per specimen). Automating the RSF and the CF testing processes, however, can increase the testing speed and the volume of product that can be tested. To automate RSF and CF testing, precautions must be taken to ensure that the specimen are properly loaded to the testing system to ensure accurate measurements. 
       FIG. 1 a    illustrates perspective view of an example testing system  100 , while  FIG. 1 b    illustrates a perspective view of the load frame  102  of the example testing system  100  with portions omitted for clarity. The testing system  100  generally comprises a load frame  102 , a load cell  106  mounted to a crosshead  108  of the load frame  102 , a platen assembly  110  at a base structure  104  of the load frame  102 , and a controller  150 . As will be discussed, the platen assembly  110  is configured to support one or more specimens  112  during compression testing (e.g., RSF or CF testing), whether through a manual or automated process. 
     As best illustrated in  FIG. 1 a   , the load frame  102  comprises a base structure  104 , one or more columns  114 , a moving crosshead  108 , and a top plate  116 . The load frame  102  serves as a high stiffness support structure against which the test forces react (e.g., compressive forces) during a test (e.g., a RSF test, compression friction measurement test, etc.). While the load frame  102  may be composed of a single column  114 , as illustrated, multiple columns  114  may be employed, for example, in a dual column arrangement. The base structure  104  generally serves to support the one or more columns  114  and a platen assembly  110  that supports the specimen  112 , while also housing various circuitry and components, such as a controller  150 . 
     The platen assembly  110  may be manually or automatically adjusted (or otherwise controlled) to move or transfer a specimen  112  to a testing position, which is typically aligned below the test head  136 , test apparatus, or other test accessory. The specimen  112  may be, for example, a container  140  for a parenteral pharmaceutical product as illustrated in  FIG. 1 b   . As best illustrated in Detail A of  FIG. 1 b   , in one example, the container  140  (e.g., a bottle with a flange  144 ) defines an opening  142  and a flange  144 . An elastomeric closure  146  covers the opening  142 . A cap  148  is crimped under flange  144  and compresses the elastomeric closure  146  to seal the opening  142 . In another example, as best illustrated in Detail B of  FIG. 1 b   , the cap  148  may be omitted whereby the elastomeric closure  146  fits within the opening  142  of the container  140  (e.g., a vial) and presses against the inner surface of the container  140  to seal the opening  142 . While the specimen  112  is illustrated as a container  140  with and without a flange  144  and/or cap  148 , other types of specimens  112  are also contemplated. 
     Each of the one or more columns  114  comprises a guide column and a ballscrew  154  that is drivingly coupled to an actuator  156 . A ball screw  154  is a form of mechanical linear actuator that translates rotational motion (e.g., from an actuator  156 , such as a motor) to linear motion with little friction. In one example, the ballscrew  154  may include a threaded shaft that provides a helical raceway for ball bearings, which acts as a precision screw. As illustrated in  FIG. 1 b   , the ballscrew  154  is housed within the one or more columns  114  between the base structure  104  and the top plate  116 . The actuator  156  that drives the ballscrew  154  is controlled via the controller  150 . A column cover  118  may be provided to protect the ballscrew  154  from dirt, grime, and damage, while also protecting the user from harm during operation. The testing system  100  comprises various sensors to monitor its operation. For example, the testing system  100  may include an upper limit switch  132  and a lower limit switch  134  to prevent the crosshead  108  from deviating from an acceptable range of motion along axis A. Upon triggering the upper limit switch  132  or the lower limit switch  134 , the controller  150  may stop (or reverse) the actuator  156  to prevent damage to the testing system  100  or the specimen  112 . 
     The crosshead  108  is mounted to both the guide column and the ballscrew  154  and supports the load cell  106 . The ballscrew  154  is driven (e.g., rotated) via an actuator  156 . Rotation of the ballscrew  154  drives the crosshead  108  up (away) or down (toward) relative to the base structure  104 , while the guide column provides stability to the crosshead  108 . The load cell  106  may be removably coupled to the crosshead  108  via one or more mechanical fasteners  138  (e.g., screws, bolts, socket head cap screws, etc.) to enable the operator to exchange the load cell  106  when desired. For example, the load cell  106  may become damaged, a different type of load cell  106  may be desired or needed, which can vary by test (e.g., RSF and CF testing). 
     The display device  126  (e.g., a touch screen display), control panel  128 , and/or remote control  130  (e.g., a handset) may be used by the operator to monitor and/or control operation of the testing system  100 . In some example, the control panel  128  and the remote control  130  may each provide one or more switches, buttons, or dials to control or adjust operation of the testing system  100  (e.g., an emergency stop button). The control panel  128  and the remote control  130  may further provide one or more status indicators (e.g., LEDs, lights, etc.) to provide a status of the testing system  100 . The remote control  130  may be wired or wireless. 
     To provide additional protection and increase safety, the load string  101  may be housed in an enclosure  120  that defines a test chamber  122 . The enclosure  120  may be fabricated from a transparent material (e.g., glass, plastic, Plexiglas, etc.) to enable the operator to observe the load string  101 . A door or access panel  124  may be provided to enable access to the test chamber  122  within the enclosure  120 . The load string  101  generally refers to the components installed between the moving crosshead  108  and the base structure  104  (or, where applicable, a fixed lower crosshead). Typically, the load string  101  includes the load cell  106 , the test head  136 , any adapters required to connect the components, and the specimen(s)  112  to be tested. Typically, for RSF testing, the load cell  106  is mounted on the crosshead  108 , a test head  136  with an anvil is mounted to the load cell  106 , and a specimen  112  is positioned on the base structure  104  (e.g., using a platen assembly  110 ). Similarly, for CF testing, a load cell  106  is mounted on the crosshead  108 , a compression rod is mounted to the load cell  106 , and a specimen  112  is positioned on the base structure  104  (e.g., using a platen assembly  110 ). 
     Operation of the testing system  100  may be automatically controlled and/or monitored via the controller  150 . The controller  150  may comprise a processor  150   a  and memory device  150   b  configured with executable instructions. The controller  150  is operably coupled to, and configured to control, the various actuators (e.g., the actuator  156  that drives the ballscrew  154 ), sensors (e.g., load cell(s)  106 , upper and lower limit switches  132 ,  134 ), user interfaces (e.g., display device  126 , control panel  128 , and/or remote control  130 ), etc. 
     During the RSF test, for example, the crosshead  108  moves down along Axis A of the load frame  102  (toward the base structure  104 ) to apply compressive load to the specimen  112  via a test head  136 , test apparatus, or other test accessory that is coupled to the load cell  106 . The test head  136  may be, or include, an anvil (also known as a dorn) configured to contact and compress the one or more specimens  112 . The test head  136 , test apparatus, or other test accessory may be coupled directly to a coupler  152  of the load cell  106  or via a compression rod or pin. 
     The load cell  106  converts this load into an electrical signal that the testing system  100  measures via controller  150  and displays to the operator via display device  126 . In one example, the test head  136  may advance at a constant speed (e.g., about 0.01 inches/second). In other words, in this example, for every 0.001 inches the crosshead  108  travels along the column  114  (along Axis A), the controller  150  automatically records the force exerted by the specimen  112  in response to the movement (strain) imposed upon the specimen  112  by the test head  136 . The constant speed may be adjusted for a given specimen  112 . The controller  150  also automatically records the corresponding strain data. The resulting data set comprises a sequence of stress-strain measurements that can be graphed, which approximates a curve of predictable shape. In the case of RSF, an adequate seal may be determined by monitoring for an inflection point on resulting curve (e.g., indicating the elastomeric closure  146  has transitioned from flexing to rigid, thus sealing the opening  142 ). 
     The test head  136  may be designed for RSF and/or CF testing. For example, the test head  136  may be a compression rod for CF testing or include an anvil for RSF testing, such as a test head with an adjustable, conforming anvil. As can be appreciated, certain tests may warrant a specific type of test head  136 . For example, the test head  136  used during RSF measurement may include an anvil that is sized and shaped to correspond to the size and shape of the closure of a parenteral container. Therefore, while the test head  136  is generally illustrated in  FIGS. 1 a  and 1 b    as being configured for RSF testing, a compression rod (and associated load cell) may instead be used for CF testing. 
     The test head  136  can be interchangeable to enable the testing system  100  to be used for various types of tests (e.g., RSF, CF, tensile, compression, flexure, etc.). In other words, the test head  136  may be configured to removably couple with the load cell  106  via, for example, a coupler  152  or other means to enable the operator to replace or interchange the test head  136  with another the test head  136 , test apparatus, or other test accessory. The coupler  152  may employ one or more of a collar coupling (e.g., a collar with one or more set pins or screws), clevis coupling, sleeve coupling, or a screw on coupling (e.g., a threaded rod). Therefore, while the coupler  152  is illustrated as a female collar coupler with set screws and/or set pins, other types of couplings are contemplated. 
     The one or more specimens  112  are supported on the base structure  104  by the platen assembly  110 . Akin to the test head  136 , certain tests may warrant a specific type of platen assembly  110 . For example, the platen assembly  110  used during RSF measurement may include one or more stations that are sized and shaped to correspond to the size and shape of the parenteral container  140  (or other specimen  112 ). That that end, the platen assembly  110  may comprise an specimen plate  110   a  that is test specific or specimen specific, and a base plate  110   b  supported by the base structure  104  and configured to support the specimen plate  110   a . The specimen plate  110   a  may be removably coupled to the base plate  110   b  to enable the operator to select a specimen plate  110   a  that is suitable for a particular test. In one example, the specimen plate  110   a  is a plate or table that is sized and shaped to support the one or more specimens  112  (e.g., via one or more recesses), while the base plate  110   b  may be a plate configured to support and/or secure the specimen plate  110   a  relative to the base structure  104 . In some examples, the specimen plate  110   a  is configured to move relative to the base plate  110   b . For example, the specimen plate  110   a  may be configured to rotate or tilt relative to the base plate  110   b  to accommodate an approach angle of the test head  136  during compression. 
     To yield accurate RSF measurements, it is important that the test head  136  firmly contact the specimen  112  (e.g., the cap  148 ) during a RSF test. This typically requires that the operator check to ensure that the specimen  112  is properly seated in the platen assembly  110  such that the flat surface of the cap  148  is flush with the contact point of the test head  136  (e.g., the anvil). In an automated approach, this introduces additional complications. 
     One option is to employ a sensor system (e.g., one or more imaging devices) to confirm a correct placement of the specimen  112 , however, sensor systems increase cost and complexity of the overall system testing system  100 . A lower cost, but robust, option is use a test head  136  with an anvil that conforms to the position of the specimen  112  by enabling both planar and radially motion of the anvil during the seating portion of the RSF compression test to ensure that the test head  136  firmly contacts the specimen  112  (e.g., at the cap  148 ). 
       FIG. 2 a    illustrates a plan cross-sectional view of a first example test head  200  in accordance with aspects of this disclosure. As illustrated, the test head  200  generally comprises a housing  202 , an anvil  204 , a ball roller assembly  208 , and a retaining ring  203 . The ball roller assembly  208  is configured to provide a point of contact  224  between the housing  202  and the anvil  204  during a RSF test. In some example, the retaining ring  203  is positioned within the first cavity  222  and configured to maintain the anvil  204  at least partially within the first cavity  222 . During the RSF test, the compressive forces push the anvil  204  into the first cavity  222 . The retaining ring  203  is configured to maintain the anvil  204  at least partially within the first cavity  222  in the absences of such compressive forces. The retaining ring  203  also provides a limit on the radially pivot  228  of the anvil  204  within the first cavity  222 . The test head  200  defines a proximal end  218  having a first coupler  232  configured to engage with a second coupler  152  of the testing system  100  and a distal end  220  having a recess  206  configured to engage a specimen  112 . The recess  206  may be sized and shaped to engage a surface of the cap  148  of the specimen  112 . In some examples, an example of which is illustrated in  FIG. 2 a   , a washer  234  can be positioned at the contact point between the anvil  204  and the retaining ring  203  to provide or adjust a limit on the radially pivot  228  of the anvil  204  within the first cavity  222 . Though not illustrated, the washer  234  can be similarly configured in connection with the other views of the test head  200 . 
     As illustrated, the anvil  204  is configured to float within the first cavity  222 , thereby allowing a surface of the anvil  204  conform to the surface of the cap  148 . In an automated process, for example, a plurality of specimens  112  may be preloaded and/or automatically fed to or by the platen assembly  110 . Such movement can result in a specimen  112  being improperly seated (e.g., crooked). The accuracy of the RSF measurements decreases when the contact between the anvil  204  and the cap  148  is not flush. Therefore, to ensure that the cap  148  of the specimen  112  is properly seated in the recess  206  of the anvil  204 , the anvil  204  is configured to move relative to the housing  202  in both a planar motion  226  (e.g., side-to-side) and to pivot radially  228  relative to the housing  202 . 
     In some examples, the housing  202  defines a first cavity  222  and the anvil  204  is positioned at least partially within the first cavity  222 . The outer diameter of the anvil  204  may be sized to allow for lateral movement in a plane of the anvil  204  within the first cavity  222 . In other words, the inner diameter of the first cavity  222  may be larger than the outer diameter of the anvil  204  by a predetermined distance (D) to allow for some play within the first cavity  222 . The predetermined distance (D) may be, for example, 1 to 10 millimeters. When the anvil  204  is centered in the first cavity  222 , as illustrated in  FIG. 2 b   , half of the distance (D/2) is available on each side of the anvil  204  for the planar motion  226 . 
     The ball roller assembly  208  generally comprises a sphere  210 , a roller housing  212 , and a plurality of ball bearings  214 . The ball roller assembly  208  may be rated to support  180 N of compressive load. The plurality of ball bearings  214  serve to reduce friction between the sphere  210  and the roller housing  212 . The ball roller assembly  208  may be positioned in a second cavity  216 . For example, the ball roller assembly  208  can be press fit into the second cavity  216 . In the illustrated example, the housing  202  defines a second cavity  216 , however, as will be described in connection with  FIGS. 3 a  through 3 c    where the anvil  204  may define the second cavity  216 , other arrangements are contemplated. The housing  202 , the anvil  204 , and/or the sphere  210  may be fabricated from a metal or a metal alloy, such as stainless steel. 
       FIGS. 2 b  and 2 c    illustrate plan cross-sectional views of the first example test head of  FIG. 2 a    in contact with a specimen  112  that is improperly seated at a first angle and a second angle, respectively. The ball roller assembly  208  provides a single point of contact  224  between the housing  202  and the anvil  204 . As illustrated, the ball roller assembly  208  enables the anvil  204  to move in a planar motion  226  relative to the housing  202 . During an RSF test, the anvil  204  can move in a planar motion  226  and/or  228  radial motion  228  such that the recess  206  of the anvil  204  is flush with the specimen  112 . 
       FIG. 2 d    illustrates a plan cross-sectional view of the first example test head with a concave region at the point of contact. Over time, the single point of contact  224  may create a wear point (e.g., a divot) on the anvil  204 . As can be appreciated, a divot could prohibit the anvil  204  from freely floating, thereby reducing accuracy of the RSF measurements. To mitigate wear, the anvil  204  may define a concave region  230  at the single point of contact  224  that corresponds to the surface of the sphere  210 , thereby increasing contact area with the ball roller assembly  208 . The concave region  230  may alternatively be positioned on the housing  202  when the ball roller assembly  208  is secured to the anvil (e.g., as illustrated in  FIG. 3 a  through 3 c   ). 
       FIG. 3 a    illustrates a plan cross-sectional view of a second example test head  300  in accordance with aspects of this disclosure, while  FIGS. 3 b  and 3 c    illustrate plan cross-sectional views of the second example test head  300  in contact with a specimen  112  that is improperly seated at a first angle and a second angle, respectively. The test head  300  of  FIGS. 3 a  through 3 c    is substantially the same as the test head  200  of  FIGS. 2 a  through 2 c    except that the anvil  204  defines the second cavity  216  for the ball roller assembly  208 . In this example, the ball roller assembly  208  is press fit into the second cavity  216  of the anvil  204 . 
       FIG. 4 a    illustrates a perspective view a third example test head  400  in accordance with aspects of this disclosure, while  FIG. 4 b    illustrates a plan cross-sectional views of the third example test head taken along section A-A of  FIG. 4 a   . The test head  400  of  FIGS. 4 a  and 4 b    is similar to test heads  200 ,  300  in that it facilitates planar motion  226  and radial motion  228 , however, test head  400  splits the planar motion  226  and radial motion  228  into two separate mechanisms. Specifically, planar motion  226  is provided via a plurality of ball bearing assemblies  418  and radial motion  228  is provided via a ball roller assembly  416 . 
     The test head  400  generally comprises a first housing  402 , a second housing  404 , and an anvil  406 . The first housing  402  defines a first cavity  412  and the second housing  404  defining a second cavity  414 . The second housing  404  is positioned at least partially within the first cavity  412  and is configured to move in a planar motion  226  relative to the first housing  402 . An anvil  406  positioned at least partially within the second cavity  414  and configured to pivot radially  228  relative to the second housing  404 . As illustrated, the anvil  406  is configured to pivot radially  228  relative to the second housing  404  using a ball roller assembly  416 . The ball roller assembly  416  comprises a sphere  408  and a roller housing  410 . 
     A plurality of ball bearing assemblies  418  are provided to reduce friction between the surface of the first and second housings  402 ,  404 . In some examples, as illustrated, the plurality of ball bearing assemblies  418  are press fit into cavities defined in the second housing  404 , however, the plurality of ball bearing assemblies  418  may instead be press fit into cavities defined in the first housing  402 . In some example, the ball roller assembly  416  may further comprises a plurality of ball bearings (not illustrated) between the sphere  408  and the roller housing  410 . 
       FIG. 5  is a flowchart representative of an example method  500  for performing an automated residual seal force RSF test in a testing system  100 . The testing system  100  comprises a load cell  106  configured to move along a column  114  toward and away from a base structure  104  via a crosshead  108 . 
     At step  502 , a plurality of specimens  112  are loaded to a specimen plate  110   a . The plurality of specimens  112  are loaded to a specimen plate  110   a  may be loaded through a manual or automated process. The plurality of specimens  112  comprises a first specimen  112  and a subsequent specimen  112  (e.g., a second specimen  112 ). 
     At step  504 , the specimen plate  110   a  is positioned in a first position that situates the first specimen  112  at a testing position of the testing system  100 . The specimen plate  110   a  can be positioned in a first position manually (e.g., by the operator before the test is commenced) or via an actuator. 
     At step  506 , the actuator  156  advances the crosshead  108  along the column  114  toward the base structure  104  to compress the first specimen  112 . 
     At step  508 , the processor  150   a , which is operatively coupled to the load cell  106 , determines a residual seal force of the first specimen  112 . 
     At step  510 , the actuator  156  retracts the crosshead  108  along the column  114  away the base structure  104 . 
     At step  512 , the specimen plate  110   a  is moved in a second position that situates the subsequent specimen  112  at the testing position. 
     At step  514 , the actuator  156  advances the crosshead  108  along the column  114  toward the base structure  104  to compress the subsequent specimen  112 . 
     At step  516 , the processor  150   a  determines a residual seal force of the subsequent specimen  112 . 
     Steps  512  through  516  may be automatically repeated for each subsequent specimen  112  until each of the plurality of specimens  112  loaded to the specimen plate  110   a  is tested. 
     While the present method and/or system has been described with reference to certain implementations, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the present method and/or system. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from its scope. For example, block and/or components of disclosed examples may be combined, divided, re-arranged, and/or otherwise modified. Therefore, the present method and/or system are not limited to the particular implementations disclosed. Instead, the present method and/or system will include all implementations falling within the scope of the appended claims, both literally and under the doctrine of equivalents.