Patent Publication Number: US-11660629-B2

Title: Systems and methods for inspecting and cleaning a nozzle of a dispenser

Description:
RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 15/871,977, filed Jan. 15, 2018 and issued as U.S. Pat. No. 10,906,058, which claims priority to U.S. Provisional Patent App. No. 62/451,356, filed Jan. 27, 2017, the entire disclosures of which are hereby incorporated by reference as if set forth in their entirety herein. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to systems and methods for treating a nozzle of a dispenser, and more particularly, to systems and methods for inspecting and cleaning a dispensing nozzle with a cleaning substrate having a plurality of hook structures. 
     BACKGROUND 
     Dispensing processes of jetting technology can become ineffective due to excessive accumulation of material on an exterior surface of a nozzle. Excessive accumulation can hinder the dispensing of fluid or viscous material and/or truncate the lifecycle of the dispensing equipment. Maintenance often requires the operator to periodically pause the production cycle and manually inspect multiple nozzles to ensure that excessive accumulation has not occurred. However, manual inspection and cleaning can be difficult because of the small size of the nozzles, the nozzles are typically not visible without use of a mirror, and the operator is often responsible for multiple dispensing machines. 
     Furthermore, the cleaning substrates currently applied to cleaning dispensers are often ineffective. For example, fabrics and sponges do not provide sufficient scrubbing and lack durability due to the fluid or viscous materials quickly clogging their pores. Fabrics and sponges can also shed which is not suitable for a clean room environment. Brushes are another potential cleaning substrate, but have similar problems in addition to being too abrasive, potentially damaging the nozzles. Therefore, there is a need for cleaning dispensing nozzles more effectively in an automated manner. 
     SUMMARY 
     The foregoing needs are met, to a great extent, by the systems and methods described herein In one aspect, a system for cleaning a nozzle of a dispenser may include a platform and a cleaning substrate supported by the platform. The cleaning substrate may have a plurality of hook structures configured to remove a material from the nozzle. 
     Another aspect is directed to a method of cleaning a nozzle of a dispenser. The method may include providing a cleaning substrate having a plurality of hook structures, and moving at least one of the nozzle and the cleaning substrate relative to the other to remove a material from the nozzle. 
     Yet another aspect is directed to a method of inspecting a nozzle of a dispenser. The method may include dispensing a fluid or viscous material with the nozzle, and capturing an image, with a camera, of the nozzle after dispensing. The method may also include processing the image to generate a value based on a pixel intensity of the image, and utilizing the value to determine if the nozzle should be cleaned. The method may further include cleaning the nozzle based on the determination that the nozzle should be cleaned. 
     Still a further aspect is directed to a dispensing system including a platform and a nozzle of a dispenser moveable relative to the platform. The dispensing system may include a camera positioned underneath the platform and configured to capture an image of the nozzle, and a cleaning substrate supported by the platform and having a plurality of hook structure. The system may further include a controller configured to generate one or more signals to dispense a fluid or viscous material from the nozzle, and actuate the camera to capture an image of the nozzle. The one or more signals may process the image to generate a value, and utilize the value to determine if the nozzle should be cleaned. The one or more signals may further move at least one of the nozzle and the cleaning substrate relative to the other to remove at least some of the fluid or viscous material from the nozzle with the hook structures in response to a determination that the nozzle should be cleaned. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the disclosure may be readily understood, aspects of this disclosure are illustrated by way of examples in the accompanying drawings. 
         FIG.  1    illustrates an exemplary dispensing system. 
         FIG.  2    illustrates an exemplary service system of the dispensing system of  FIG.  1   . 
         FIG.  3    illustrates a first exemplary cleaning station of the service station of  FIG.  2   . 
         FIG.  4    illustrates a second exemplary cleaning station of the service station of  FIG.  2   . 
         FIGS.  5 A-C  illustrate an exemplary method of cleaning a dispensing nozzle with the service station of  FIG.  2   . 
         FIGS.  6 A-D  illustrate additional aspects of the exemplary method of cleaning the dispensing nozzle of  FIGS.  5 A-C . 
         FIG.  7    provides an exemplary flow chart depicting a first method of cleaning a nozzle of a dispenser. 
         FIG.  8    provides an exemplary flow chart depicting a second method of cleaning a nozzle of a dispenser. 
         FIGS.  9 A-C  illustrate exemplary images captured of the dispensing nozzle of  FIGS.  5 A-C . 
         FIG.  10    provides an exemplary flow chart depicting the method of inspecting of the dispensing nozzle of  FIGS.  9 A-C . 
     
    
    
     The same reference numbers reference the same parts in the drawings and the detailed description. 
     DETAILED DESCRIPTION 
     Systems and methods for inspecting and cleaning at least one dispensing nozzle are described. The system includes a platform supporting a cleaning substrate having a plurality of hook structures configured to remove a material from the nozzle of the dispenser. The hook structures may comprise the hook portion of, for example, a Velcro or DuraGrip branded fastener. The hook structures may provide a number of benefits over fabrics, clothes, and brushes used as cleaning substrates, such as durability, a gentle scrubbing on the nozzle, minimal or no shedding, and/or a favorable configuration for trapping and retaining the material removed from the nozzle. Furthermore, material with hook structures are readily available in various sizes, density, and hook shapes to optimize cleaning with various nozzle structures and materials. In some embodiments, two or more of the dispensing nozzles may be secured to a common head and may be cleaned with the cleaning substrate at the same time or separately. For example, the dispensing nozzles may be moveable relative to each other along a z-axis to be separately wiped against the cleaning substrate. 
     In some embodiments, the cleaning substrate may be dry, and in some embodiments, the cleaning substrate may be positioned in a container and at least partially submerged (or covered) in a cleaning solvent. A drying substrate may, therefore, be provided to remove the cleaning solvent from the nozzle after the nozzle has been submerged in the cleaning solution. A camera may be positioned underneath the platform to capture an image of the nozzle. A controller may be configured to process the image to generate a value based on the amount of material coated on the nozzle. The nozzle may be moved relative to the cleaning substrate to wipe the nozzle, or vice versa. The movement of the nozzle and/or cleaning substrate may include at least of one of a linear pattern, a zigzag pattern, a rectangular pattern, a square pattern, an oval pattern, and a circular pattern. 
       FIG.  1    illustrates an exemplary dispensing system  10  including a cabinet  12  and one or more dispensing assemblies  14 . Each of the dispensing assemblies  14  may include a dispensing nozzle  16  having a valve (depicted in  FIGS.  9 A-C ) for selectively dispensing controlled amounts of fluid or viscous material onto a substrate  18  (e.g., a circuit board) positioned on a working area  26  of the cabinet  12 . The dispensing assembly  14  may also include a camera  20  and a height sensor  21 . The dispensing nozzle  16  may be a needle dispenser, a spray dispenser, a jetting dispenser, or any other device suitable for dispensing fluid or viscous materials such as adhesives, epoxies, or solder pastes onto the substrate  18  from a fluid material reservoir  23 . 
     As illustrated, the dispensing systems  10  may include first and second dispensing assemblies  14  for dispensing material onto either a single substrate or separate substrates. Each of the dispensing assemblies  14  may be coupled to a positioner  25  configured to selectively position the dispensing assemblies  14  above the working area  26  and/or a service station  28  of the cabinet  12 . The positioner  25  may include one or more cross supporting structures  30 , each supporting one or more dispensing assemblies  14  and extending between opposite side supporting structures  31 . The dispensing assemblies  14  may move in an x-direction along the cross supporting structure  30  through common or separate motorized assemblies (not shown). The cross supporting structure  30  may move the dispensing assemblies  14  in a y-direction relative to the side supporting structures  31  via rolling assemblies powered by linear motors (not shown). The positioner  25  may also include a z-axis drive  34  configured to move one or more of the dispensing assemblies  14  in a z-direction to adjust the height of the dispensing assembly  14  and/or dispensing nozzle  16  relative to the working area  26  and/or the service station  28 . The positioner  25  may thereby provide three substantially perpendicular axes of motion for the dispensing assembly  14 . For example, a pair of dispensing assemblies  14  may be positioned on a common head and be moved together in the x- and y-directions, while having separate z-axis drives  34 . Therefore, the dispensing assemblies may dispense two different materials on a single substrate, such that one of the dispensing assemblies  14  may be toggled (or lifted in the z-direction out of the way) while the other of the dispensing assemblies is in use. In another example, the pair of dispensing assemblies  14  may simultaneously dispense the same material on a substrate to speed up production. The positioner  25  may adjust the relative positioning between the pair of dispensing assemblies  14  to accommodate skewed substrates along the x-, y-, and/or z-axes. In another example, the pair of dispensing assemblies  14  may be moved independently in the x- and y-directions, but moved simultaneously in the z-direction along the x-, y-, and/or z-axes. In yet another example, the dispensing assemblies may be moved completely independently. 
     The dispensing system  10  may also include a controller  36 , which may be a computer mounted in the cabinet  12 . The controller  36  may be configured to provide overall control of the dispensing system  10 , such as coordinating movements of the dispensing assembly  14 , actuating the dispensing nozzle  16 , and/or actuating components of the service station  28 . The controller  36  may include a processor, a memory, and an input/output (I/O) interface. The processor may include one or more devices selected from microprocessors, micro-controllers, digital signal processors, microcomputers, central processing units, field programmable gate arrays, programmable logic devices, state machines, logic circuits, analog circuits, digital circuits, or any other devices that manipulate signals (analog or digital) based on operational instructions that are stored in the memory. The memory may be a single memory device or a plurality of memory devices including but not limited to read-only memory (ROM), random access memory (RAM), volatile memory, non-volatile memory, static random access memory (SRAM), dynamic random access memory (DRAM), flash memory, cache memory, or any other device capable of storing digital information. The memory may also include a mass storage device (not shown) such as a hard drive, optical drive, tape drive, non-volatile solid state device or any other device capable of storing digital information. The processor may operate under the control of an operating system that resides in memory. The operating system may manage controller resources so that computer program code embodied as one or more computer software applications. 
     A user interface  38  and/or a control panel  40  may be operatively coupled to the controller  36  to allow a system operator to interact with the controller  36 . The user interface  38  may include a video monitor, alphanumeric displays, a touch screen, a speaker, and any other suitable audio and/or visual indicators capable of providing information to the system operator. The control panel  40  may include one or more input devices capable of accepting commands or input from the operator, such as an alphanumeric keyboard, a pointing device, keypads, pushbuttons, control knobs, microphones. In this way, the user interface  38  and/or the control panel  40  may enable manual initiation of system functions, for example, during set-up, calibration, inspection, and/or cleaning. 
       FIG.  2    illustrates an exemplary service station  28  configured to inspect and clean a nozzle of the dispensing nozzle  16 . As shown, the service station  28  may include a platform  48  supporting one or more of a calibration station  50 , a touch sensor station  52 , a purge station  54 , a weighing station  56 , an inspection station  58 , and a cleaning station  60 . 
     The calibration station  50  may be configured to calibrate the x/y-position of the dispensing nozzle  16 . For example, the calibration station  50  may provide a fixed reference point that can be captured by the camera  20  and/or the height sensor  21 , which generates a signal to the controller  36 . The controller  36  may then calibrate the x/y-position of the camera and/or the height sensor  21  based on the signal. 
     The touch sensor station  52  may be configured to calibrate the z-position of the dispensing nozzle. For example, the dispensing nozzle  16  may be lowered toward the touch sensor station  52  until contact is initially sensed by a pressure sensitive region of the touch sensor station  52 . Based on the initial contact by the dispensing nozzle  16 , a signal is generated by the touch sensor station  52  and transmitted to the controller  36 . The controller  36  may then calibrate the z-position of the dispensing nozzle  16 . 
     The purge station  54  may be configured to remove waste material from the dispensing nozzle  16 . For example, the purge station  54  include a source of vacuum configured to generate negative pressure to suck the fluid or viscous material and/or cleaning material from a surface of the dispensing nozzle. The vacuumed material may be deposited in a reservoir (not shown) positioned underneath the platform  48 . 
     The weighing station  56  may be configured to calibrate the material of the dispensing system  10 . For example, the weighing station  56  may include a scale configured to receive and weigh one or more droplets from the dispenser. The scale may then generate a signal indicative of the weight, which is transmitted to the controller  36 . Based on the weight of the material, the controller  36  may calibrate the material deposited by the dispensing nozzle  16 . 
     The inspection station  58  may be configured to inspect the dispensing nozzle  16  to detect accumulation of material on the dispensing nozzle  16 . As shown in  FIG.  2   , the inspection station  58  may include a camera  62 , an angled mirror  64 , and a transparent cover  66 . The camera  62  may be positioned substantially horizontal and underneath the platform  48 . The angled mirror  64  may be positioned underneath the transparent cover  66  and aligned with the camera  62 , such that the angled mirror  64  may be configured to reflect a vertical image of the dispensing nozzle  16  horizontally to the camera  62  (as depicted in  FIGS.  9 A-C ). The transparent cover  66  may protect the angled mirror  64  from any fluid or viscous material that might drip from nozzle  16 . The transparent cover  66  may be easier to clean and/or replace than the angled mirror  64 . The camera  62  being positioned substantially horizontally within the service station  28  may reduce the required thickness of the dispensing system  10 . However, it is also contemplated that the camera  62  may be positioned substantially vertically within the service station  28 , thereby obviating the need for the angled mirror  64 . In either case, the camera  62  may capture an image of an opening of the dispensing nozzle  16  and transmit the image to the controller  36 . The controller  36  may process the image to determine an amount of material accumulated on the dispensing nozzle  16 . For example, in some embodiments, the camera  62  may capture the image in greyscale, and the controller  36  may process the image to generate a value indicating a pixel intensity of the image, as further discussed below. 
     The cleaning station  60  may be configured remove material from a surface of the dispensing nozzle  16 . As depicted in  FIGS.  2 - 5   , the cleaning station  60  may include a cleaning substrate  68  configured to remove material from an exterior surface of the dispensing nozzle  16 . The cleaning substrate  68  may include a plurality of book structures  70  supported by a backing  72  and configured to wipe a material  74  from an exterior surface of the dispensing nozzle  16  (as depicted in  FIG.  5 A- 5 C ). In some embodiments, the cleaning substrate  68  may comprise the hook portion of a Velcro or DuraGrip branded fastener. For example, the hook structures  70  may comprise a substantially rigid and durable material, such as nylon or polyester, configured to gently scrub the dispensing nozzle  16 , and trap the material  74  between the hook structures  70  and the backing  72 . In some embodiments, the cleaning station  60  may have the cleaning substrate  68  in a wet configuration at least partially submersed or covered in a cleaning solvent  76  (as depicted in  FIGS.  2 - 3   ). In other embodiments, the cleaning station  6 ) may have the cleaning substrate  68  in a dry configuration (as depicted in  FIG.  4   ). 
     Referring to  FIGS.  2 - 3   , the cleaning station  60  may include a base  78  configured to support a container  80  containing the cleaning solvent  76 . The cleaning station  60  may also include a lower substrate housing  82  and an upper substrate housing  84  configured to releasably secure the cleaning substrate  68  sandwiched therein. The upper substrate housing  84  may include a tab  85  on each end configured to snap into a slot  83  on each end of the lower substrate housing  82 . However, other releasable mechanisms may be utilized to allow removal and/or cleaning of the cleaning substrate  68 . The upper substrate housing  84  may also include an opening  87  through which the hook structures  70  extends to expose the hook structures  70  for wiping against the dispensing nozzle  16 . The cleaning substrate  68  may also include a border without the hook structures  70 , which may be clamped between the upper substrate housing  84  and the lower substrate housing  82 . 
     The cleaning station  60  may further include a lid  86  slideably secured between an upper lid housing  91  and a lower lid housing  92 . The lid  86  may be opened and closed with a lid actuator  88 . For example, the lid  86  may include a protrusion  89  received within a slot  90  of an actuator arm  93 . The actuator arm  93  may be secured to a piston rod  94  configured to extend and retract in/out of a chamber  96  to open and close the lid  86  with respect to the container  80 . The lid  86  may enclose the container  80  to reduce evaporation of the cleaning solvent  76 , when the cleaning substrate  68  is not in use. The upper lid housing  91  and the lower lid housing  92  may be secured with fasteners, such as screws or rivets. The cleaning station  60  may include a releasable assembling mechanism to releasably assemble the cleaning station  60 , such as a first magnet included in or on the base  78  and a second magnet included in or on the lower lid housing  92 . The magnetic assembly of the cleaning station may facilitate removing, cleaning, and/or replacing the cleaning substrate  68  and/or the cleaning solvent  76 . 
     The hook structures  70  may be partially or fully submerged (or covered) in the cleaning solvent  76 . The cleaning solvent  76  may be an alcohol- or water-based solvent configured to remove and/or dissolve the material  74  while the dispensing nozzle  16  is wiped against the cleaning substrate  68 . Simple Green All-Purpose Cleaner (which may contain ethoxylated alcohol) is an especially effective cleaning solvent  76  for a clean-room environment because of the non-toxic nature. 
     The cleaning station  60  may further include a level control system (not shown) configured to maintain a predetermined amount of the cleaning solvent  76 . The level control system may include a level sensor, a filling device, and a reservoir containing the cleaning solvent  76  (not shown). The level sensor may include a number of different mechanisms configured to detect the level of the cleaning solvent  76 , such as a float sensor, a hydrostatic sensor, a laser sensor, magnetic sensor, a capacitance sensor, and an ultrasonic sensor. The level sensor may generate a signal indicative of a level of the cleaning solvent  76  to the controller  36 . The controller  36  may compare the level of the cleaning solvent  76  to a predetermined threshold. The controller  36  may then generate a signal to the filling device to add cleaning solvent  76  to the container  80  based on the detected level. Accordingly, the filling device may include a valve configured to selectively enable a flow of the cleaning solvent  76  to the container  80 . 
     Following cleaning in the cleaning solvent  76 , the dispensing nozzle  16  may be dried with a drying substrate  98 . The drying substrate  98  may include a fabric or a sponge configured to remove the cleaning solvent  76  when placed in contact with the dispensing nozzle  16 . The drying substrate  98  may be positioned in a number of different positions on or around the service station  28 . For example, the drying substrate  98  may be positioned on an outer surface of the lid  86  to minimize required movement of the dispensing nozzle  16  during the cleaning and drying. When the lid  86  is closed, the drying substrate  98  may substantially overly the cleaning substrate  68  in the z-direction. Therefore, minimal or no x-y movement of the dispensing nozzle  16  would be required to put the dispensing nozzle  16  in contact with drying substrate  98  after the dispensing nozzle  16  is removed from the cleaning solvent  76 . However, it is contemplated that the drying substrate  98  may be positioned in other locations, such as directly on the platform  48 . 
     As depicted in  FIG.  4   , in some embodiments, the cleaning station  60  may have the cleaning substrate  68  in a dry configuration. The cleaning substrate  68  may be secured to a cleaning substrate support  100  releasably secured to the base  78 . For example, the substrate housing  82 ,  84  and the cleaning substrate support  100  may be interchangeable to the cleaning station  60  to allow for changing between the wet configuration and the dry configuration of the cleaning substrate  68  based on dispensing conditions. For example, the cleaning substrate support  100  may also include a releasable assembling mechanism, such as a magnet configured to be releasably secured to the base  78  allowing for quick interchangeable assembly. 
     The dispensing system  10  may include a plurality of service stations  28 , and/or the service station  28  may include a plurality of one or more of its components. For example, in embodiments having a plurality of dispensing nozzles  16 , the service station  28  may include a plurality of cameras  62  and/or mirrors  64  for independent inspection of the plurality of dispensing nozzles  16 . Similarly, in some embodiments, the service station  28  may include a plurality of cleaning substrates  68  for independent cleaning of the plurality of dispensing nozzles  16 . In some embodiments, the plurality of dispensing nozzles  16  may be cleaned and/or inspected by separate service stations  28 . 
       FIGS.  5 A-C  illustrate an exemplary method of cleaning the dispensing nozzle  16  with the cleaning substrate  68 . As depicted in  FIG.  5 A , the dispensing nozzle  16  is covered with a material  74  and may be advanced along the z-axis, with the positioner  25 , toward the cleaning substrate  69 . The dispensing nozzle  16  is moved, with the positioner  25 , laterally along the hook structures  70  to remove the material  74  from the surface of the dispensing nozzle  16 . The material  74  is then retained and trapped between the hook structures  70  and the backing  72  of the cleaning substrate  68 . As depicted in  FIG.  5 C , the dispensing nozzle is retracted along the z-axis away from the cleaning substrate  68  following cleaning. In embodiments having a plurality of dispensing nozzles  16 , the dispensing nozzles  16  may be cleaned at the same time or separately. For example, when wiped separately,  FIG.  5 A  may indicate the movement of a first dispensing nozzle  16  toward the cleaning substrate  68  along the z-axis and relative to (e.g., away from) a second dispensing nozzle  16 .  FIG.  5 B  may then indicate the movement of the first dispensing nozzle  16  together with or separately from the second dispensing nozzle  16 .  FIG.  5 C  may then indicate movement of the first dispensing nozzle  16  away from the cleaning substrate along the z-axis and relative to (toward) the second dispensing nozzle  16 . When wiped together, the first and second nozzles  16  may be jointly moved toward the cleaning substrate  68  (as illustrated in  FIG.  5 A ) and jointly moved away from the cleaning substrate  68  (as illustrated in  FIG.  5 C ). 
       FIGS.  6 A-D  illustrate additional aspects of the exemplary method of cleaning the dispensing nozzle of  FIGS.  5 A-C . As illustrated in  FIGS.  6 A-C , the controller  36  (or a user) may move the dispensing nozzle  16  relative to the cleaning substrate  68  in multiple different directions in the x-y plane to wipe the dispensing nozzle  16 . The controller  36  (or a user) may move or wipe the dispensing nozzle  16  relative to the cleaning substrate  68  in a first direction, and the controller  36  may then move or wipe the dispending nozzle relative to the cleaning substrate  68  in a second direction different from the first direction, and so forth. For example, as depicted in  FIG.  6 A , the dispensing nozzle  16  may be moved or wiped in a first diagonal direction and a second diagonal direction. In some embodiments, the first and/or second diagonal directions are repeated with any number of repetitions, as exemplified by the zigzag movement illustrated in  FIG.  6 A . In some embodiments, the first and second directions may have rounded transitions, for example, forming a sinusoidal pattern along the cleaning substrate  68  (not shown). As depicted in  FIG.  6 B , the dispensing nozzle  16  may be moved or wiped in a first horizontal direction, a second vertical direction, a third horizontal direction, and a fourth horizontal direction, as exemplified by the rectangular movement. It is also contemplated that the horizontal and vertical directions of  FIG.  6 B  may be equal forming a square movement. As depicted in  FIG.  6 C , the dispensing nozzle  16  may be moved or wiped in multiple directions to form an oval movement, but it is further contemplated that the major and minor axes of  FIG.  6 C  may be the same to form a circular movement. 
     As illustrated in  FIG.  6 D , the dispensing nozzle  16  may be moved, with the positioner  25  and/or a user, relative to first and second portions of the cleaning substrate  68  according to an indexing method. For example, the dispensing nozzle  16  may be moved against a first portion of the cleaning substrate  68 , and then indexed. The dispensing nozzle  16  may then be wiped against a second portion of the cleaning substrate  68 , and then indexed. The indexing method may be repeated for a number of different portions of the cleaning substrate (e.g., six portions depicted in  FIG.  6 D ). The indexing may indicate the number of wipes of the cleaning substrate  68  and/or the total number of wipes for each portion of the cleaning substrate  68 . After wiping each portion or wiping all of the portions, the controller  36  may determine whether the number of wipes for the cleaning substrate  68  is greater than (or equal to) a predetermined total number that indicates the end of the lifecycle of the cleaning substrate  68  and/or the portion of the cleaning substrate  68 . If the controller  36  determines the number of wipes is less than (or equal to) the predetermined total number of wipes, the controller  36  may determine that the cleaning substrate  68  and/or portion thereof is within the lifecycle and/or may continue to use the cleaning substrate  68  and/or portion thereof. However, if the controller  36  determines that the number of wipes is greater than (or equal to) the predetermined total number of wipes, the controller  36  may determine the end of the lifecycle of the cleaning substrate  68  and/or portion thereof. The controller  36  may, additionally, generate an audio and/or visual indication, as further discussed below. 
     Wiping the dispensing nozzle  16  on different portions of the cleaning substrate  68  creates a more uniform and distributed build-up on the cleaning substrate  68 , increasing the overall lifecycle of the cleaning substrate  68 . The indexing method also allows an operator to quantitatively monitor the lifecycle of the cleaning substrate and/or automate the lifecycle in a favorable manner. As shown in  FIG.  6 D , the indexing method may include linear wipes, but it is also contemplated that the indexing method may include other types of movements, such as those discussed in connection with  FIGS.  6 A-C . 
       FIG.  7    provides an exemplary flow chart depicting a method  700  of cleaning a nozzle of a dispensing nozzle  16 . Method  700  may be performed with the cleaning substrate  68  in either a wet configuration ( FIG.  3   ) or a dry configuration ( FIG.  4   ). Each of the steps of method  700  may be performed based on one or more signals generated by the controller  36 . The method  700  may also be performed in conjunction with one or more steps of method  800  ( FIG.  8   ) and/or method  1000  ( FIG.  10   ). 
     In step  702 , the dispensing nozzle  16  may dispense a fluid or viscous material onto a substrate  18 . In some embodiment, step  702  may apply a conformal coating onto a printed circuit board. For example, the dispensing nozzle  16  may apply a thin polymeric film conforming to contours of a printed circuit board to protect the board&#39;s components. Step  702  may, additionally or alternatively, dispense the fluid or viscous material in a flip chip underfill procedure. The controller  36  may perform step  702  for a predetermined period (e.g., about 1-2 dispensing hours), a predetermined number of cycles, and/or any number of other metrics that estimate the accumulation of material on a surface of the dispensing nozzle  16 . After the metric has elapsed, the controller  36  may proceed to step  704  for inspection. 
     In step  704 , the controller  36  may inspect the dispensing nozzle  16 . The controller  36  may inspect the dispensing nozzle  16  by actuating the camera  62  and processing an image to generate a value, as illustrated in the flow chart of  FIG.  10   . However, the inspecting of step  704  may be performed in a number different of other manners. 
     In step  706 , the controller  36  may determine if the dispensing nozzle is sufficiently clean. For example, step  706  may be performed by determining if the value is within a range relative to (e.g., greater than or equal to) a predetermined value indicating a clean dispensing nozzle  16 . If the value is within the range indicating a clean dispensing nozzle  16 , the controller  36  may return to step  702  to continue dispensing with the dispensing nozzle  16 . However, if the value is not within the range indicating a clean dispensing nozzle  16 , the controller  36  may proceed to step  708 . 
     In step  708 , the controller  36  may open the lid  86  of the cleaning station  60  to expose the cleaning substrate  68  having the plurality of hook structures  70 . The opening may be performed by actuating the lid actuator  88  to extend the piston rod  94  from the chamber  96 , as depicted in  FIG.  3   . Step  708  may be omitted in configurations of the cleaning station  60  having a dry cleaning substrate  68 . 
     In step  710 , the controller  36  may move at least one of the dispensing nozzle  16  and the cleaning substrate  68  relative to the other to remove a material from the dispensing nozzle  16 . For example, the controller  36  may actuate the positioner  25  to move the dispensing nozzle  16  to align with the cleaning substrate  68 . The controller  36  may then lower the dispensing nozzle  16  to contact the cleaning substrate  68 , and move the dispensing nozzle in one or more directions with respect to the cleaning substrate  68  to remove the material from the dispensing nozzle  16  with the hook structures  70  of the cleaning substrate  68 . In a preferred embodiment, the dispensing nozzle  16  may be moved against one or more portions of the cleaning substrate  68  according to the indexing of method  800 . 
     In step  712 , the controller  36  may remove the dispensing nozzle  16  from the cleaning substrate  68  the cleaning station  60  and inspect the dispensing nozzle  16 . For example, the controller  36  may inspect the dispensing nozzle  16  as discussed in step  704  and illustrated in  FIG.  10   . 
     In step  714 , the controller  36  may determine if the nozzle is sufficiently clean. If the nozzle is not sufficiently clean (“NO”), the controller  36  may return to step  710  to move at least one of the dispensing nozzle  16  and the cleaning substrate  68  relative to the other to remove additional material from a surface of the dispensing nozzle  16 . Based on the nozzle not being sufficiently clean (“NO”), the controller  36  may perform an indexing method to prevent an infinite loop. For example, the controller  36  may update an index and compare the index to a predetermined value to determine whether to return to step  714 . The index exceeding the predetermined value may indicate a saturated cleaning substrate  68  or low level of cleaning solvent  76 , such that the controller  36  may pause the method  700  and generate an indication (e.g., visual and/or audible) with the user interface  38  to the operator. If the dispensing nozzle  16  is sufficiently clean (“YES”), the controller  36  may proceed to step  716 . 
     In step  716 , the controller  36  may close the lid  86  to reduce evaporation of the cleaning solvent  76 . The controller  36  may close the lid  86  with the lid actuator  88 , by retracting the piston rod  94  into the chamber  96 . 
     In step  718 , the controller  36  may dry the dispensing nozzle  16 . In some embodiments, the controller  36  may move the dispensing nozzle  16  against the drying substrate  98  to remove the cleaning solvent  76 . In some embodiments, the controller  36  may move the dispensing nozzle  16  to the purge station  54  and actuate the vacuum of the purge station  54  to remove the cleaning solvent  76  from the dispensing nozzle  16 . After drying, the controller  36  may return the dispensing nozzle  16  to dispensing the fluid or viscous material. Step  718  may be omitted in configurations of the cleaning station  64 ) having a dry cleaning substrate  68 . 
     In embodiments having a plurality of dispensing nozzles  16 , the dispensing nozzles  16  may be inspected and/or cleaned simultaneously or independently depending on the configuration. For example, the dispensing nozzles  16  may be inspected with separate cameras  62 , and cleaned using a common positioner  25  and applying the same or separate cleaning substrates  68 . 
       FIG.  8    provides an exemplary flow chart depicting method  800  of cleaning the dispensing nozzle  16 . Method  800  may be performed with the cleaning substrate  68  in either a wet configuration ( FIG.  3   ) or a dry configuration ( FIG.  4   ). Each of the steps of method  800  may be performed based on one or more signals generated by the controller  36 . It is contemplated that the method  800  may be performed in conjunction with one or more steps of method  700  ( FIG.  7   ) and/or method  1000  ( FIG.  10   ). Method  800  may be performed following the dispensing of a fluid or viscous material by the dispensing nozzle  16  (e.g., step  702 ), and inspection of the dispensing nozzle  16  (e.g.,  704 ). In method  800 , the controller  36  may cycle through different portions of the cleaning substrate  68  during the cleaning process, as discussed below. 
     In step  802 , the controller  36  may move the dispensing nozzle  16  against a first portion of the cleaning substrate  68 , as depicted in  FIGS.  5 A- 5 C and  6 D . The movement of the dispensing nozzle  16  may include at least of one of a linear pattern, a zigzag pattern, a rectangular pattern, a square pattern, an oval pattern, and a circular pattern. 
     In step  804 , the controller  36  may generate or updated an index to indicate the number of the times that the dispensing nozzle  16  has been moved against the cleaning substrate  68  and/or the first portion of the cleaning substrate  68 . The controller  36  may then inspect the dispensing nozzle  16  (e.g., step  714 ) and/or perform additional dispense (e.g., step  702 ) after step  804 . 
     In step  806 , the controller  36  may move the dispensing nozzle  16  against a second portion of the cleaning substrate  68  (as further depicted in  FIGS.  4 A-C  and  6 D) after dispensing (e.g., step  702 ) and inspecting (e.g., step  704 ), similar to step  802 . 
     In step  808 , the controller  36  may iterate the index, similar to step  804 . Step  808  may update the same index of step  804  when the nozzle is moved uniformly against each portion of the cleaning substrate  68 . This may simplify the process because each of the portions of the cleaning substrate  68  may accumulate material and wear in a similar manner. However, it is also contemplated that the controller  36  may generate separate indexes for each of the portions of the cleaning substrate  68 . The steps  810 ,  812  may be repeated for any number of portions of the cleaning substrate  68 . For example, as depicted in  FIG.  6 D , steps  810 ,  812  may be repeated for each of the third, fourth, fifth, and sixth portions. 
     In step  810 , the controller  36  may compare the index to a predetermined value. If the index is below the predetermined value (“NO”), the controller  36  may return to step  802  to continue wiping the dispensing nozzle  16  against the same cleaning substrate  68  after dispensing (e.g., step  702 ) and inspecting (e.g.,  704 ). In some embodiments, the controller  36  may also generate and display on the user interface  38  an indication of a status of the cleaning substrate  68 , such as the lifecycle remaining and/or elapsed (e.g., 90% remaining). Therefore, an operator may replace and/or repair the cleaning substrate  68  at a time that is convenient to the flow of production. However, if the index is determined to exceed the predetermined value, the controller  36  may proceed to step  812 . 
     In step  812 , the controller  36  may indicate the end of the life cycle of the cleaning substrate  68 . For example, the controller  36  may generate and display a visible message to an operator through the user interface  38 . It is also contemplated that the controller  36  may, additionally or alternatively, generate an audible indicator, such as an alarm, a bell, and/or a whistle to the operator. The dispensing system  10  may also include multiple cleaning substrates, such that a second cleaning substrate  68  is available following the life cycle of a first cleaning substrate  68 . 
       FIGS.  9 A-C  illustrate exemplary images captured of the dispensing nozzle  16  to be processed, and  FIG.  10    provides an exemplary flow chart depicting a method  1000  of inspecting the dispensing nozzle  16 . Method  1000  may be performed with the cleaning substrate  68  in either a wet configuration ( FIG.  3   ) or a dry configuration ( FIG.  4   ). Each of the steps of method  1000  may be performed based on one or more signals generated by the controller  36 . It is contemplated that the method  1000  may be performed in conjunction with one or more steps of method  700  ( FIG.  7   ) and/or method  800  ( FIG.  8   ). 
     In Step  1002 , the dispensing nozzle  16  may dispense a fluid or viscous material onto a substrate  18 . In some embodiment, step  1002  may apply a conformal coating onto a printed circuit board. For example, in step  1002 , the dispensing nozzle  16  may apply a thin polymeric film conforming to contours of a printed circuit board to protect the board&#39;s components. Step  1002  may, additionally or alternatively, dispense the fluid or viscous material in a flip chip underfill procedure. The controller  36  may perform step  1002  for a predetermined period (e.g., about 1-2 dispensing hours), a predetermined number of cycles, and/or any number of other metrics that estimate the accumulation of material on an external surface of the dispensing nozzle  16 . After the metric has elapsed, the controller  36  may proceed to step  1004  for inspection. 
     In step  1004 , the controller  36  may actuate the camera  62  to capture an image of the dispensing nozzle  16 , such as an opening or valve in the dispensing nozzle  16 . The controller  36  may actuate the positioner  25  to align the dispensing nozzle  16  with the angled mirror  64 , and the z-axis drive may position the dispensing nozzle  16  a predetermined distance away from the platform  48 . As depicted in  FIG.  9 A-C , the images may be captured, by the camera  62 , in greyscale to facilitate processing and determining the amount of material accumulated on the dispensing nozzle  16 . Alternatively, the images may be captured by the camera  62  in color and then converted to greyscale to facilitate processing. 
     In step  1006 , the controller  36  may process the image. As depicted in  FIGS.  9 A-C , the controller  36  may capture a predetermined subset of the images depicting the dispensing nozzle  16 , and the subset is processed to generate a value based on the pixel intensity of the image. In some embodiment, the controller  36  may process the captured image by comparing one or more pixels of the captured image to one or more corresponding pixels of an image of a clean dispensing nozzle  16  to determine variations in pixel intensity. The pixel intensity variation may indicate an amount of material coated on the dispensing nozzle  16  because portions of the dispensing nozzle  16  coated by a material would be darker than corresponding clean portions of the dispensing nozzle  16 . The comparison would provide an array of pixel intensity variations. The controller  36  may then normalize the array to generate the value as a scalar quantity indicative of the variation in pixel intensity of the captured image and the amount of material accumulated on the dispensing nozzle  16 . 
     For example,  FIG.  9 A  depicts a dispensing nozzle  16  that is clean, lacking material accumulation indicated the amount of light pixels. The image of  FIG.  9 A  may be processed by the controller  36  to generate, for example, a high value (e.g., 80-90 on a scale of 0 to 100) to indicate that the nozzle is comparable to an image of a clean dispensing nozzle  16 ; therefore, the dispensing nozzle  16  of  FIG.  9 A  may continue to dispense without cleaning.  FIG.  9 B  depicts a dispensing nozzle  16  after a few dispensing cycles. There is minimal accumulation of material on the surface the dispensing nozzle  16 , but not sufficient to reduce dispensing efficiency. Therefore, the image of  FIG.  9 B  may be processed with the controller  36  to generate a relatively high value (e.g., 60-70 on a scale of 0 to 100). On the other hand,  FIG.  9 C  depicts a dispensing nozzle  16  having substantial material accumulation on the surface due to the number of dark pixels. The accumulation of material may block the opening of the dispensing nozzle  16  and reduce the quality of dispensing to an unacceptable level. Based on the processing of  FIG.  9 C , the controller  36  may detect the material accumulation when processing the image of  FIG.  9 C  and generate, for example, a relatively low value (e.g., 9-18 on a scale of 0 to 100). 
     In steps  1008  the controller  36  may determine if the value is within a range relative to a predetermined value indicating the dispensing nozzle  16  being sufficiently clean. For example, the predetermined value may be a predetermined percentage (e.g., 50%) of a clean nozzle, and step  1008  may determine if the value is within the range indicating the nozzle  16  is clean. If the value is determined not to be in the range indicating the nozzle  16  being sufficiently clean (“NO”), the controller  36  may proceed to step  1010 . If the value is determined to be in the range (“YES”), the controller  36  may proceed to step  1012 . 
     In step  1010 , the controller  36  may move at least one of the dispensing nozzle  16  and the cleaning substrate  68  relative to the other to remove at least some of the material from the dispensing nozzle, as further discussed in at least one of methods  700 ,  800 . For example, the cleaning of step  1012  may be performed with the hook structures  70  of the cleaning substrate  68 . After cleaning the dispensing nozzle in step  1012 , the controller  36  may return to step  1004 , where the camera  62  captures another image of the dispensing nozzle  16 . Additional cleaning may be required to make the dispensing nozzle  16  sufficiently clean for dispensing in step  1002 . 
     In step  1012 , the controller  36  may move the dispensing nozzle  16  toward the substrate  18 . The controller  36  may then proceed to step  1002 , where the dispensing nozzle  16  dispenses a fluid or viscous material onto the substrate  18 . For example, the dispensing nozzle may dispense a conformal coating onto the substrate  18  (e.g., a printed circuit board). 
     One or more of software modules incorporating the methods described above can be integrated into a computer system or non-transitory computer-readable media. Moreover, while illustrative embodiments have been described herein, the scope includes any and all embodiments having equivalent elements, modifications, omissions, combinations (e.g., of aspects across various embodiments), adaptations or alterations based on the present disclosure. Further, the steps of the disclosed methods can be modified in any manner, including by reordering steps or inserting or deleting steps. 
     As such, in a first embodiment, a system for cleaning a nozzle of a dispenser may include a platform and a cleaning substrate supported by the platform. The cleaning substrate may have a plurality of hook structures configured to remove a material from the nozzle. 
     The system of the first embodiment, wherein the hook structures comprise nylon or polyester. The system of the first embodiment, further comprising a controller configured to generate one or more signals to move at least one of the nozzle and the cleaning substrate relative to the other to remove the material from the nozzle using the plurality of hook structures. The controller is further configured to generate one or more signals to: move the nozzle against a first portion of the cleaning substrate; move the nozzle against a second portion of the cleaning substrate different than the first portion: generate an index based on a number of times the nozzle is moved against the first and second portions of the cleaning substrate; and indicate an end of a lifecycle of the cleaning substrate based on the index being greater than or equal to a predetermined value. 
     The system of the first embodiment, further comprising: a container supported by the platform and receiving the cleaning substrate; a cleaning solvent within the container and at least partially covering the hook structures; and a lid enclosing the container. The cleaning solvent includes ethoxylated alcohol. The system of the first embodiment, further comprising a level control system configured to: detect a level of the cleaning solvent; compare the detected level to a predetermined threshold; and generate, in response to the detected level being less than the predetermined threshold, a signal to add cleaning solution to the container. The system of the first embodiment, further comprising a support configured to releasably secure the cleaning substrate in the container underneath the lid. The system of the first embodiment, further comprising a drying substrate configured to remove the cleaning solvent from the nozzle. The drying substrate is positioned on an outer surface of the lid. The drying substrate comprises a fabric or a sponge. 
     The system of the first embodiment, further comprising a camera associated with the platform, the camera being configured to capture an image of the nozzle. The camera is configured to capture an image of an opening in the nozzle. The system of the first embodiment, further comprising a mirror associated with the camera, wherein the mirror is angled relative to the platform and configured to reflect the image of the opening in the nozzle to the camera. The camera and the mirror are positioned underneath the platform. The system of the first embodiment, further comprising a controller configured to generate one or more signals to: dispense a fluid or viscous material from the nozzle, actuate the camera to capture an image of the nozzle, process the image to generate a value, utilize the value to determine if the nozzle should be cleaned, and if the nozzle should be cleaned, move at least one of the nozzle and the cleaning substrate relative to the other to remove material from the nozzle with the hook structures. 
     The system of the first embodiment, further comprising at least one of a calibration station, a touch sensor station, a purge station, and a weight station. 
     A second embodiment is directed to a method of cleaning a nozzle of a dispenser. The method may include providing a cleaning substrate having a plurality of hook structures, and moving at least one of the nozzle and the cleaning substrate relative to the other to remove a material from the nozzle. 
     The method of the second embodiment, wherein moving at least one of the nozzle and the cleaning substrate includes: moving the nozzle relative to the cleaning substrate in a first direction; and moving the nozzle relative to the cleaning substrate in a second direction different from the first direction. 
     The method of the second embodiment, wherein moving the at least one of the nozzle and the cleaning substrate includes moving the nozzle relative to the cleaning substrate in at least of one of a linear pattern, a zigzag pattern, a rectangular pattern, a square pattern, an oval pattern, and a circular pattern. 
     The method of the second embodiment, further comprising: opening a lid of a container that receives the cleaning substrate and a cleaning solvent at least partially covering the hook structures; moving the nozzle into contact with the cleaning solvent and the cleaning substrate; removing the nozzle from the container; and closing the lid of the container. The method further comprising moving the nozzle into contact with a drying substrate to remove the cleaning solvent from the nozzle. The method, further comprising: detecting a level of the cleaning solvent; comparing the detected level to a predetermined threshold; and generating a signal to add cleaning solution to the container based on the detected level being less than the predetermined threshold. 
     The method of the second embodiment, further comprising: moving the nozzle proximate to a camera; capturing, with the camera, an image of the nozzle; processing the image to generate a value based on an amount of material from the nozzle; and determining if the value is within a range relative to a predetermined value, wherein moving the at least one of the nozzle and the cleaning substrate is in response to the value being within the range. The method, further comprising: moving the nozzle proximate to the camera after the moving at least one of the nozzle and the cleaning substrate relative to the other: capturing, with the camera, a second image of the nozzle; processing the second image to generate a second value based on the amount of material on the nozzle; determining if the second value is within the range; and moving at least one of the nozzle and the cleaning substrate relative to the other based on the second value not being within the range. The method, further comprising actuating the nozzle to dispensing a fluid or viscous material if the value is within the range. 
     The method of the second embodiment, further comprising: moving the nozzle against a first portion of the cleaning substrate; moving the nozzle against a second portion of the cleaning substrate different than the first portion; generating an index based on a number of times the nozzle is moved against the first and second portions of the cleaning substrate: and indicating an end of a lifecycle of the cleaning substrate based on the index being greater than or equal to a predetermined value. 
     The method of the second embodiment, further comprising: determining a total number of times the nozzle has been moved against the cleaning substrate; determine that the total number of times is greater than or equal to a predetermined total number; and indicating an end of a lifecycle of the cleaning substrate in response to the determination that the total number of times is greater than or equal to the predetermined total number. 
     The method of the second embodiment, further comprising dispensing a conformal coating onto a printed circuit board. The method of the second embodiment, further comprising moving the nozzle relative to a second nozzle and toward the cleaning substrate. Wherein moving at least one of the nozzle and the cleaning substrate relative to the other includes moving the nozzle with the second nozzle relative to the cleaning substrate. 
     A third embodiment is directed to a method of inspecting a nozzle of a dispenser. The method may include dispensing a fluid or viscous material with the nozzle, and capturing an image, with a camera, of the nozzle after dispensing. The method may also include processing the image to generate a value based on a pixel intensity of the image, and utilizing the value to determine if the nozzle should be cleaned. The method may further include cleaning the nozzle based on the determination that the nozzle should be cleaned. 
     The method of the third embodiment, wherein the utilizing the value includes determining if the value is not within a range relative to a predetermined value. The method, further comprising: capturing a second image, with the camera, of the nozzle after cleaning; processing the second image to generate a second value based on the pixel intensity of the image; determining that the second value is within the range; and moving the nozzle toward to substrate to dispensing the fluid or viscous material with the nozzle in response to the second value being within the range. 
     The method of the third embodiment, wherein cleaning the nozzle includes cleaning the nozzle with a cleaning substrate having a plurality of hook structures. The method of the third embodiment, wherein the image is in greyscale. The method of the third embodiment, wherein processing the image includes: generating an array based on pixel intensity of the image; and normalizing the array to generate the value in a scalar quantity. 
     The method of the third embodiment, wherein dispensing includes dispensing a conformal coating on a printed circuit board. The method of the third embodiment, wherein capturing the image includes receiving a reflected image from a mirror, the camera being positioned underneath a platform and oriented at an angle relative to a platform. 
     A fourth embodiment is directed to a dispensing system including a platform and a nozzle of a dispenser moveable relative to the platform. The dispensing system may include a camera positioned underneath the platform and configured to capture an image of the nozzle, and a cleaning substrate supported by the platform and having a plurality of hook structure. The system may further include a controller configured to generate one or more signals to dispense a fluid or viscous material from the nozzle, and actuate the camera to capture an image of the nozzle. The one or more signals may process the image to generate a value, and utilize the value to determine if the nozzle should be cleaned. The one or more signals may further move at least one of the nozzle and the cleaning substrate relative to the other to remove at least some of the fluid or viscous material from the nozzle with the hook structures in response to a determination that the nozzle should be cleaned. 
     Wherein the controller is configured to utilize the value to determine if the value is not within a range relative to a predetermined value. Wherein the hook structures comprise nylon or polyester. Wherein the controller is further configured to generate one or more signals to: determine a total number of times the nozzle has been moved against the cleaning substrate; determine that the total number of times is greater than or equal to a predetermined total number; and indicate an end of a lifecycle of the cleaning substrate in response to the determination that the total number of times is greater than or equal to the predetermined total number. 
     The system of the fourth embodiment, further comprising: a container supported by the platform and receiving the cleaning substrate; a cleaning solvent within the container and at least partially covering the hook structures; and a lid enclosing the container. Wherein the cleaning solvent includes ethoxylated alcohol. The system, further comprising a level control system configured to: detect a level of the cleaning solvent; compare the detected level to a predetermined threshold; and generate, in response to the detected level being less than the predetermined threshold, a signal to add cleaning solution to the container. The system, further comprising a housing configured to releasably secure the cleaning substrate in the container underneath the lid. The system, further comprising a drying substrate configured to remove the cleaning solvent from the nozzle. Wherein the drying substrate is positioned on an outer surface of the lid. Wherein the drying substrate comprises a fabric or a sponge. 
     The system of the fourth embodiment, wherein the camera is configured to capture an image of an opening in the nozzle. The system, further comprising a mirror associated with the camera, wherein the mirror is angled relative to the platform and configured to reflect the image of the opening in the nozzle to the camera. The system, wherein the camera and the mirror are positioned underneath the platform.