Abstract:
A system and associated method is provided for sorting parts, which includes a conveyor system for receiving and circulating a plurality of randomly presented parts, a sorting buffer for accumulating selected parts from the plurality of randomly presented parts in an assigned buffer location, and a sequencing system for sequencing the accumulated selected parts.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of application Ser. No. 11/553,330, filed Oct. 26, 2006, now U.S. Pat. No. 8,030,588, the disclosure of which is incorporated herein in its entirety. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     This invention relates to the sorting of objects, and more particularly to the sorting of mass produced, customized objects. 
     2. Description of the Related Art 
     Sorting devices are known for separately guiding finished parts to different discharge areas adjacent to tooling or packaging machines. Typically, sorting devices operate as a post-processing tool that is used to sort finished pieces. 
     Generally, finished pieces are identified on the basis of the quality of the material or the type of material. For example, only parts possessing a similar quality of material are selected and packaged together. The packaging station performs similar operations on similar parts. In most instances, parts having unique or customized features that must be packaged together are not readily accommodated. Presently, the sorting and packaging of unique, customized parts must be done manually to ensure accuracy. 
     Accordingly, there is a need to provide a simple and efficient sorting and selecting system that brings a variety of associated objects together during a production process with resulting improvements in efficiency and productivity. 
     SUMMARY 
     The present invention provides a system and associated method for sorting mass produced, customized objects. 
     In one aspect of the invention, a part sorting process is provided including loading a plurality of randomly presented parts; sorting at least one selected part of the randomly presented parts into a group of associated parts; and sequencing the group of associated parts. 
     In yet another aspect of the invention, a system is provided for sorting parts. The invention includes a system for receiving and continuously circulating a plurality of randomly presented parts. The invention also includes a sorting buffer for accumulating selected parts from the plurality of randomly presented parts in an assigned buffer location, and a sequencing system for sequencing the accumulated selected parts. 
     A more complete understanding of the invention can be obtained by reference to the following detailed description of the embodiments thereof in connection with the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which: 
         FIG. 1A  is a flowchart of a sorting system process in accordance with an embodiment of the present invention; 
         FIG. 1B  is a simplified illustration of a dental aligner on a carrier in accordance with an embodiment of the present invention; 
         FIG. 2  is a simplified illustration of components of a load cell of a sorting system in accordance with an embodiment of the present invention; 
         FIGS. 3A-3D  are simplified illustrations of components of the load cell of  FIG. 2  in accordance with an embodiment of the present invention; 
         FIG. 4  is a simplified illustration of an indexing table unloading parts and placing them on carriers in accordance with an embodiment of the present invention; 
         FIG. 5  is a simplified illustration of a reader in accordance with an embodiment of the present invention; 
         FIG. 6A  is a simplified illustration of components of a sorting buffer cell in accordance with an embodiment of the present invention; 
         FIG. 6B  is a simplified illustration of the operation of a buffer conveyor associated with the sorting buffer cell in  FIG. 6A  in accordance with an embodiment of the present invention; 
         FIG. 7  is a simplified illustration of components of a puck sequencing cell in accordance with an embodiment of the present invention; 
         FIG. 8  is a simplified illustration of a storage cell in accordance with an embodiment of the present invention; and 
         FIG. 9  is a simplified illustration of a quality control station in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the detailed description of the invention that follows, the invention is described primarily in the context of a system and method for sorting mass produced customized dental appliances, such as dental aligners. It should be understood, however, that the system and processes of the present invention may be employed in the sorting of any of various types of items, work pieces or parts, such as prosthetic body parts, implantable hearing aids, eyeglass lenses and the like. 
       FIG. 1A  is a flowchart representing manufacturing cells of a sorting system  100  in accordance with an embodiment of the present invention. In pre-processing cell  102 , if necessary, parts may undergo a pre-processing step in which the parts are cleaned, sanitized, or otherwise prepared for traversing sorting system  100 . 
     Load cell  104  represents a process for the introduction of a batch or plurality of items or parts that are manually (or alternatively, automatically) loaded into sorting system.  100  via a bulk supply pre-feeder mechanism. The pre-feeder mechanism delivers parts to a part distribution and circulation system, which includes a system of conveyors that distribute the parts over a conveyor for presentation to a vision system. In one embodiment, the quantity of parts delivered may be a metered quantity of the entire batch of parts delivered periodically to the part distribution and circulation system to avoid overwhelming the system. 
     The vision system, including a robot picker, identifies the part location and orientation, then picks up and places each part onto an indexing table at a loading position. In one embodiment, the robot picker in conjunction with the vision system selects only parts having a desired top/bottom up orientation and places them on the indexing table. In yet another embodiment, the robot picker in conjunction with the vision system selects a part and manipulates the part, if necessary, until the part has the desired orientation before placing the part onto the indexing table. For example, the robot picker may pick a part having a bottom up orientation and then rotate the part until it has a top up orientation before placing the part onto the indexing table. 
     Alternatively, as described in greater detail below, the robot picker may place a part on the indexing table without regard to the part&#39;s orientation. The indexing table then indexes to a vision station so that the part can be scanned for top/bottom orientation. Once the part orientation is determined, the indexing table then indexes to a reorientation station, which includes a mechanism capable of rotating the part, as required, to achieve a desired top/bottom up orientation. 
     Once properly oriented, the indexing table indexes to a ‘unique code’ read station so that a unique code of each part can be read and ultimately mapped to a particular corresponding part carrier or “puck.” After the indexing table indexes to an unload station, the properly oriented and identified parts are unloaded by a pick-and-place unit or the equivalent into the corresponding pucks. 
     In one embodiment, each puck may be identified by a radio frequency identification device (RFID). The puck&#39;s RFID and the unique code are “mapped” to each other and the data is stored in a database. Before exiting load cell  104 , each puck is scanned by a subsequent vision system to verify “part presence.” 
     The pucks are conveyed from load cell  104  to a sorting buffer cell  106 . Alternatively, the pucks may be conveyed to an exceptions handling cell  108 , which may include one or more manual quality assurance stations (QAS). 
     In one embodiment of sorting buffer cell  106 , the pucks travel to a walking beam past an RF reader or the equivalent. The RF reader identifies the unique code number and temporarily assigns the unique code to one of a number of buffer lanes. If the number of parts to be included in one group requires more than one lane, the group may be logically split among buffer lanes to assure that the parts are sequenced correctly. The walking beam advances pucks in a controlled motion to the head of the sorting buffer lanes. Once a puck gets to its assigned lane, the puck is pushed out of the path of the walking beam and into its assigned lane. Pucks are accumulated in their assigned lanes until all parts in the batch are sorted. When a lane is filled with a completed group or case of associated parts, the group is released to the unload section of sorting buffer cell  106  when space is available. Buffer lanes are then released one at a time from the unload section of sorting buffer cell  106 . 
     Routing system cell  110  includes a series of conveyors with merge and divert units routing pucks between the cells throughout sorting system  100 . For example, the conveyors rout pucks from load cell  104  to sorting buffer cell  106  or exceptions handling cell  108  and back to load cell  104 , from sorting buffer cell  106  to storage cell  112  and/or puck sequencing cell  114 , and from puck sequencing cell  114  to packaging cell  116  or to exceptions handling cell  108  and back to load ceil  104 . Note that exceptions handling cell  108  may include more than one QAS, thus parts that are routed to exceptions handling cell  108  during various stages of the sorting process may be routed to the QAS associated with that particular stage. 
     Incomplete groups are routed from sorting buffer cell  106  to the incomplete case storage cell  112 . In one embodiment, the pucks move via a conveyor, stop at an unloading station and are picked-and-placed on to a pallet. When the pallet is loaded it travels to an inserter/extractor (I/E) station. The pallet is transferred to the I/E via a standard lift and transfer. The I/E then moves the pallet to a shelf in a horizontal carousel for storage. When the last missing part or parts of a group arrives at incomplete case storage cell  112 , the I/E picks the pallets with the associated parts and places the pallets onto the conveyor for transport to a loading station. At the loading station, the group is completed and is then moved to puck sequencing cell  114 . 
     At puck sequencing cell  114 , the pucks are transferred to a walking beam and moved past a series of lanes. The lanes of the conveyor are assigned, for example, 1 through 50 and when each puck is in front of the proper lane it is transferred onto a stop/start take away conveyor. Once all pucks are transferred they are released by the conveyor where they then travel in the proper sequence to packaging cell  116 . 
     If a puck is marked “no read” at load cell  104  or sorting buffer cell  106 , the puck is diverted to exceptions handling cell  108 , which includes more than one QAS positioned throughout sorting system  100 . In one embodiment, the manual QAS includes an RF reader provided to read an ID tag disposed on the puck. A quality assurance computer terminal is used to allow an operator to manually enter an ID number of the puck and thus re-initialize the puck into sorting system  100 . The operator then releases the puck to be merged back into the main line ahead of sorting buffer cell  106 . The manual QAS also introduces direct batches of products that do not enter sorting system  100  through load cell  104 . 
     Generally, in one embodiment of the present invention, the mass produced, customized objects are dental appliances, referred to as a dental aligners, such as the dental aligner illustrated in  FIG. 1B . Dental aligner  118  may be formed from a dental mold made from a computerized model representing digitally a patient&#39;s dental geometry and tooth configuration or, alternatively, from an impression made of a patient&#39;s teeth. 
     The computerized model of the patient&#39;s teeth may be digitally manipulated to portray a new tooth arrangement (i.e. an orthodontic prescription) and a mold may be produced to reflect each successive arrangement in the prescription. This may be repeated any number of times to derive a number of molds with differing tooth arrangements. 
     The series of computer models or digital data sets representing the dental geometries or orthodontic prescription associated with the series of molds is used to fabricate a series of dental aligners by disposing the dental molds in a thermoplastic fabrication machine. The series of dental aligners form a group of associated aligners that need to be sorted from other groups of associated aligners and properly sequenced before packaging. 
     In one exemplary embodiment, as shown in  FIG. 1B , aligner  118  may be fabricated to fit within a 75 mm diameter, and have a weight less than 8 ounces. Aligner  118  may be laser marked with patient information and aligner sequence with an upper or lower designation. 
     Dental aligner  118  may be of the type described, for example, in U.S. Patent Application Publication No. 2005/0082703, which is incorporated herein by reference. 
     1. Load Cell 
       FIG. 2  is a simplified illustration of load cell  104  of sorting system  100  in accordance with an embodiment of the present invention. In one embodiment, load cell  104  includes a bulk supply pre-feeder  202 , a part circulation system  204 , a robot loader  208 , including or working in conjunction with a vision system  210 , and an indexing table  214 . 
     In one operational embodiment, a batch of parts  201 , such as aligners  118  ( FIG. 1B ), are loaded into bulk supply pre-feeder  202 . In one embodiment, as many as approximately 500 aligners  118  may be fed into bulk supply pre-feeder  202  in one operation. In one embodiment, aligners  118  arrive at bulk supply pre-feeder  202  after pre-processing or a pre-treatment for example, after having been cleaned, tumbled and disinfected. 
     In one embodiment, part circulation system  204  includes a metering conveyor  216 , a vision belt conveyor  206 , a return conveyor  218 , and a return elevating bucket assembly  220 . Bulk supply pre-feeder  202  may dispense a portion of the batch of aligners  118  in metered quantities onto metering conveyor  216  based on a signal from a level sensor  203  mounted proximate to or on metering conveyor  216 . Level sensor  203  senses gaps between bunches of aligners  118  that have been dispensed on metering conveyor  216 . For example, when the gaps become larger than a predetermined size, bulk supply pre-feeder  202  is made to dispense more aligners  118  into the system. As described below, aligners  118  that are disposed onto metering conveyor  216  from the return elevating bucket assembly  220  also create a portion of the bunches of aligners. 
     An exemplary bulk supply pre-feeder  202  may be a three and a half (3-V2) cubic foot pre-feeder, which is available as Farason Model GF-3.6, from Farason Corporation of Pennsylvania. 
     In one embodiment, to ensure that aligners  118  are distributed evenly onto vision belt conveyor  206  and are separated in a single layer, one or more rotating paddlewheels  222  with pliable spokes are mounted adjacent the end of metering conveyor  216  and the beginning of vision belt conveyor  206 . The pliable spokes may be mounted on a horizontal axle or, alternatively, on one more vertical spindles. Paddlewheels  222 , receive aligners  118 , such that the pliable spokes separate aligners  118  to keep aligners  118  from grouping in large clumps onto vision belt conveyor  206 . This increases the number of “pickable” parts dispersed onto vision belt conveyor  206 . 
     Alternatively, parts  201  can be delivered directly from bulk supply pre-feeder  202  onto vision belt conveyor  206 . In this alternative embodiment, bulk supply pre-feeder  202  may include a funnel shaped dispenser that allows parts  201  to be dispensed only along a single vertical plane, thus ensuring that the parts are dispersed in a separated manner. 
     Paddlewheels  222  distribute or spread aligners  118  over vision belt conveyor  206  for presentation to robot loader  208  in combination with a vision system  210  (hereinafter, in combination, “robot system  212 ”). As described below, aligners  118  are picked up from vision belt conveyor  206  and placed onto indexing table  214  by robot system  212 . A suitable type of robot system  212  is available as an Adept Cobra 800 Scara Robot with Adept Vision. 
     Aligners  118  not removed by robot system  212  fall off vision belt conveyor  206  and return to metering conveyor  216  via the return conveyor  218  and return elevating bucket assembly  220  so that aligners  118  can be circulated and thus represented to robot system  212 . 
     In operation, returning aligners  118  are discharged off the end of return conveyor  218  into return elevating bucket  224 . The bucket cycles may be based on a level sensor  226  mounted in return elevating bucket  224 , which indicates when enough parts (e.g. aligners) have been collected for return to metering conveyor  216 . In one embodiment, return elevating bucket  224  elevates aligners  118  (as shown in phantom) and dispenses them onto metering conveyor  216 , which may be mounted directly overhead and parallel to vision belt conveyor  206  and return conveyor  218 . Metering conveyor  216  is cycled on and off to meter aligners  118  onto vision belt conveyor  206 . In one embodiment, parts not unidentifiable by robot system  212  are rejected into a manual removal hopper  230  at the end of the operation for manual identification at a manual QAS. 
     Robot system  212  identifies the location and orientation of part  201  on vision belt conveyor  206 , picks up and places each part  201  onto indexing table  214  at the loading position. 
     When no pickable parts are available to be processed from the current batch of aligners  118 , the cycle for the batch is considered complete. The machine may automatically switch to “cleanout,” which means bucket  224  remains in an elevated location proximate to metering conveyor  116 . Any remaining rogue parts  201  (i.e. aligners  118 ) then exit the back of the machine into manual removal hopper  230  for manual retrieval. 
     An exemplary type of part circulation system  204 , including a metering conveyor, a vision conveyor, a return conveyor, and a return elevating bucket assembly, is available as Farason Model SRFF-30 FaraFeeder, from Farason Corporation of Pennsylvania. 
     As shown in  FIG. 3A , indexing table  214  includes part holders  302 , which are designed shaped and configured to receive and hold parts  201 . In one embodiment, part holder  302  may be designed and shaped to hold and receive aligners  118 . 
     As shown in  FIG. 3B , indexing table  214  may receive aligners  118  in any top-up or top-down orientation. Accordingly, to ensure that aligners  118  axe in an acceptable orientation, indexing table  214  indexes to a vision station  304  so that aligners  118  may be scanned for top-up or to down orientation. In operation, vision station  304  identifies the top-up or top-down orientation of aligner  118 . 
     As shown in  FIG. 3C , if it has been determined that aligner  118  is not in a desired orientation, when indexing table  214  indexes to reorientation station  306 , at least one orienting device  308  is employed to manipulate aligner  118 , as required, to achieve the desired orientation in holder  302 . For example, orienting device  308  grips aligner  118  having the top-down, orientation and removes it from holder  302 . Indexing table  214  continues to rotate the same holder  302  to the next incremental position. Simultaneously orienting device  308  rotates aligner  118  180° to achieve a top-up orientation. Orienting device  308  then replaces aligner  118  back into its same holder  302 . 
     As shown in  FIG. 3D , indexing table  214  then indexes to a ‘code’ read station  310 . Code read station  310  includes a vision system  316  including a processor or computer. Vision system  316  reads an identification mark preformed on aligner  118 , such as a laser code. The computer is used to access the vision system software for initial setup of the code read or for re-programming. 
     In operation, vision system  316  identifies aligner  118  and maps the aligner to a carrier  402 , (hereinafter puck  402 , see  FIGS. 1B and 4 ) used to ferry aligner  118  through the remaining sorting process. In one embodiment, each puck  402  is identified using an ID system, such as that which uses a small RFID for identification and tracking purposes. An RFID tagging system includes the tag, a read/write device, and a host system application, for data collection, processing, and transmission. An RFID tag may include a chip, memory and an antenna. 
     As shown in  FIG. 4 , after an aligner  118  has been identified and mapped to puck  402  at code read station  310  ( FIG. 3D ), indexing table  214  moves to an ‘unload’ station where pick and place unit  404 , for example, a robot arm with a vacuum end arm tool, unloads aligner  118 , and places aligner  118  into puck  402 , which is being conveyed on conveyor  406 . Pick and place unit  404  may be designed to unload any volume of parts, for example, two at a time. 
     “No reads” from vision system  316  may occur from time to time due to an illegible code on part  201 . If this occurs, vision system  316  sends a “no read” signal to a manual quality control station. The RFID tag on puck  402  to be mapped to the unidentified part  201  is marked with a “no read” bit and routed to the manual quality control station for identification. 
     2. Sorting Buffer Cell 
     As previously described, pucks  402  including parts  201  are conveyed from load cell  104  to sorting buffer cell  106  or, in the case of the ‘no reads’, to exceptions handling cell  108 . Sorting buffer cell  106  is used to group parts  201  into predetermined groups. Thus, the randomly loaded parts  201  that enter load cell  104  are placed into predetermined groups as desired. 
     In one embodiment, as shown in  FIGS. 5 and 6A , sorting buffer cell  106  includes a conveyor  502 , a reader  504 , such as an RF reader or the equivalent, and a walking beam  600 . In operation, pucks  402  travel on conveyor  502  past reader  504  to walking beam  600 . Reader  504  identifies puck  402 , which includes the unique part  201 , as part of a specific grouping of parts  201 . For example, in one embodiment, part  201  is aligner  118  having a unique shape and size. Aligner  118  may be one of a group of aligners representing a full prescription of aligners  118  for use with a single patient. Thus, as reader  504  identifies pucks  402  including aligners  118  as belonging to the predetermined prescription, processing capabilities associated with reader  504  cause pucks  402  to be temporarily assigned to one of a number of buffer lanes  604  ( FIG. 6A ) designated for aligners  118  for the predetermined prescription. Thus, assignment of buffer lanes  604  corresponds with the desired grouping. Thus, each new “case”, “group” or “prescription” to enter walking beam  600  has a new buffer lane  604  assigned. Buffer lanes  604  are assigned to cases in a logical order. If the size of the grouping requires more than one buffer lane  604 , the order is logically split among buffer lanes  604 . For example, if a case exceeds 50 aligners  118 , the case is assigned two buffer lanes  604  and pucks  402  are separated according to case or prescription number. 
     As shown in  FIG. 6A , in operation, walking beam  600 , includes a buffer conveyor  602 , buffer lanes  604  and pushers  606 . In operation, after reader  504  ( FIG. 5 ) reads the ID, such as the RFID tag on puck  402 , puck  402  is conveyed to buffer conveyor  602 . In one embodiment, buffer conveyor  602  may be equipped with a motor and encoders (not shown.) so that each revolution of the motor equals one puck move or step. 
     In operation, as shown, in  FIG. 6B , to advance pucks ( 1 ,  2 , from in front of corresponding buffer lanes (A, B, C) to in front of corresponding buffer lanes (B, C, D), buffer conveyor  602  moves one increment to the right casing pucks ( 1 ,  2 ,  3 ) to move one position. Buffer conveyor  602  then moves back away from pucks ( 1 ,  2 ,  3 ) and then to the left. Once back in its original position, buffer conveyor  602  moves forward to once again surround pucks ( 1 ,  2 ,  3 ). Pucks  402  are advanced in this controlled stepping motion so that each puck  402  may be paused at the head of each new buffer lane  604  before being moved to the head of the next buffer lane  604 . 
     Once puck  402  has reached the head of its assigned buffer lane  604 , puck  402  is pushed, while paused, out of the path of buffer conveyor  602 . Puck  402  is pushed using pushers  606  into sorting buffer lanes  604 . In one embodiment, pushers  606  may be pneumatically or hydraulically activated pistons. Alternatively, pucks  402  may be pushed into buffer lanes  604  using a robotic picker or a burst of air and the like. 
     Accordingly, pucks  402  accumulate in their assigned buffer lanes  604  until all aligners  118  entering load cell  104  are sorted into their associated groups. In one embodiment, when a buffer lane  604  is filled with a completed group, such as a full prescription of aligners  118 , the group may be released to the unload section of sorting buffer cell  106 . In one embodiment, buffer lanes  604  may be about 35 feet long and 4 feet wide and may have a belt speed for moving pucks  402  down the lane of about 60 ft/minute. Buffer lanes  604  also may include a series of release gates (not shown) for allowing the removal of a group of pucks  402 . Buffer lanes  604  are released one at a time from the unload section of sorting buffer cell  106  to puck sequencing cell  114 . 
     In one embodiment, the gross production rate for sorting buffer cell  106  may be about 60 parts per minute. In addition, sorting buffer cell  106  may include up to 30 buffer lanes  604 , which may hold up to 50 pucks  402 , yielding an overall capacity of 3000 pucks  402 . In addition, sorting buffer cell  106  may also have a downstream capacity equal to that of the upstream capacity. 
     In the event that reader  504  ( FIG. 5 ) is unable to read an RFID tag, the unidentified puck  402  may be routed to the manual quality control station where an operator may need to manually re-enter the unidentified puck into the system. If the operator manually re-enters the unidentified puck into the system before the batch has completed its cycle, the puck is sent to the proper buffer lane  604 . Subsequently, the completed group of pucks is directed to puck sequencing cell  114 . 
     3. Puck Sequencing Cell 
     After aligners  118  are grouped into buffer lanes  604 , they are next placed in a predetermined sequence. As illustrated in  FIG. 7 , puck sequencing cell  114  includes sequencing walking beam  702  and stop/start take away conveyor  706 , which may be running at 60 ft/min. Prior to entering puck sequencing cell  114 , pucks  402  index past an RFID reader similar to that shown in  FIG. 5 . The reader reads the RFID tag associated with puck  402  and places the value in a moving register. Pucks  402  are then indexed to the corresponding sequencing lane  704 . Sequencing walking beam  702  may be equipped with a motor and an encoder (not shown) so that each revolution of the motor equals one puck move followed by a pause in the same manner as described above with regard to  FIGS. 6A and 6B . Each time the pucks  402  move, the RFID number is moved accordingly in the register. 
     Once puck  402  has reached its assigned position, puck  402  is pushed using pushers  708  during the pause out of the path of sequencing walking beam  702  and onto start/stop take away conveyor  706  into an assigned lane  704 . This process repeats until the maximum number of parts is in their correct positions in lanes  704 . Once it has been verified that all pucks  402  have made it to the proper positions, puck sequencing cell  114  releases the group of parts  201  to packaging cell  116 . 
     In one example, aligners  118  in pucks  402  are to be placed in a sequence numbered 1-N for clarity. Pucks  402  are conveyed and transferred to sequencing walking beam  702  and moved past sequencing lanes  704 . Sequencing lanes  704  of stop/start take away conveyor  706  are assigned 1 through N lanes  704 , for example, 1-50. As puck  402  is positioned by sequencing walking beam  702  in front of the proper sequencing lane  704 , puck  402  with aligner  118  is transferred onto the stop/start take away conveyor  706 . Once all pucks  402  are transferred, which means that aligners  118  for a particular prescription are positioned in the desired number sequence, pucks  402  are released by conveyor  706  and are moved in the desired sequence to packaging cell  116  for further processing. Sequencing walking beam  702  and transfer designs may be identical to those used in walking beam  600  of sorting buffer cell  106 . 
     In one embodiment, puck sequencing cell  114  may operate at a rate of 45 PPM and may be able to buffer a maximum of 50 aligners  118 . 
     Referring again to  FIGS. 5 and 6A , it may happen that a puck  402  holding aligner  118  is not identified by reader  504  ( FIG. 5 ) and may need to be re-circulated. Meanwhile, the group of identified pucks  402  continues to be held in a particular buffer lane  604  until all associated aligners  118  of a particular group are gathered in the designated buffer lanes  604 . In one embodiment, after a default time has been reached, the incomplete group of identified pucks  402  may be diverted to an incomplete case storage cell  112 . 
     4. Incomplete Case Storage Cell 
     Incomplete groups or cases  801  of parts  201  are routed from sorting buffer cell  106  to incomplete case storage cell  112  (hereinafter “storage cell  112 ”). As shown in  FIG. 8 , pucks  402  move via a conveyor  803 , to an unloading station  816  and are picked-and-placed via a pick-and-place mechanism  802  to a pallet  804 . When pallet  804  is loaded it travels to a standard Inserter/Extractor (I/E) unit  808 . In one embodiment, I/E unit  808  causes pallet  804  to move to a shelf  810  in a horizontal carousel  812  for storage. When the last missing aligners  118  of an associated group  801  makes it to storage cell  112 , I/E unit  808  picks pallet  804  with the associated aligners  118  and places pallets  804  onto a conveyor for transport to a loading station. At the loading station, the group is completed. The group of pucks  402 , now completed, is moved to puck sequencing cell  114 . 
     In one operational embodiment, incomplete cases  801 , which are identified at sorting buffer cell  106 , are routed to storage cell  112  via conveyor system  803 . Pucks  402 , including aligners  118 , stop at a loading/unloading station  816  where a maximum of four pucks  402  are picked and placed using pick-and-place mechanism  802  onto pallet  804 . In this embodiment, a maximum of 16 pucks  402  are held on a 4×4 pallet  804  with a maximum of 4 different cases or groups  801  stored on each pallet  804 . 
     Pallet  804  moves via a conveyor  807  to I/E unit  808 . I/E unit  808  vertically moves pallet  804  to access particular shelves  810  located within carousel bins  814  in horizontal carousel  812  for storage. 
     When the last missing aligner  118  of a particular case  801  moves to storage cell  112 , the system reverses the storage process and removes the proper pucks  402  (i.e. pallets) for the particular case  801 . Pallets  804  housing the remaining aligners  118  are removed from horizontal carousel  812  using I/E unit  808  and are placed back on conveyor  807 . Pallets  804  are then transported to the loading/unloading location  816 . Pucks  402  are picked and placed back onto main conveyor  803  and held until all aligners  118  for that case  801  are once again present. After all pucks  402  are in position and ease  801  is full, case  801  is released to puck sequencing cell  114 . 
     In one operational embodiment, storage cell  112  may operate at a rate of 4 pallets per minute or up to 64 pucks per minute if all 16 places on each pallet are full. 
     Storage cell  112  handles incomplete cases  801  and stores them until such time that it has been verified that all parts  201  have arrived. In one embodiment, cases  801  may be resolved within 24 hours. In one embodiment, a query may be made for a list of aligners  118  stored in storage cell  112 , which may be sorted by “time in”. 
     In one embodiment, it may be possible to get a “no pick” from the pick and place mechanism  802  either from conveyor  803  to pallet  804  or from pallet  804  to the conveyor. If this occurs, pick-and-place mechanism  802 , after placing pucks  402  it has already picked, goes back to the “no pick” position and re-picks the missing puck  402 . 
     5. Exceptions Handling Cell 
     If a puck  402  is marked “no read” at load cell  104  or sorting buffer cell  106 , the non-read puck  402  is diverted to exceptions handling cell  108 , which includes one or more manual quality control stations  900 . Manual quality control station  900  may include an RF reader  902  provided to read the RFID tag on puck  402 . Manual quality control station  900  may also include a computer terminal  904  that allows an operator to manually enter the code number of puck  402  and aligner  118  and thus initialize it in the system. The operator may release the puck  402  and so it may be merged back into the main line ahead of sorting buffer cell  106 . If the operator can enter the information before the current batch of aligners  118  has been transferred to the discharge end of sorting buffer cell  106  then it can be sent to the proper buffer lane  604  ( FIG. 6A ) just as if puck  402  had come from load cell  104 . If, however, the operator cannot enter aligner  118  in time, puck  402  is sent through sorting buffer cell  106  to storage cell  112 . Alternatively, manual quality control station  900  can also introduce direct batches of parts that do not enter the sorting system through load cell  104 . 
     In accordance with the present invention, each cell of the present invention includes routing capabilities that are well known in the art. Routing system  110  includes, for example, a series of conveyors with merge and divert units routing pucks  402  throughout sorting system  100 . Conveyors and conveying techniques are used to rout pucks  402  from the load cell to the sorting buffer cell or to the manual quality control station and back to the load cell, from the sorting buffer cell to the incomplete case storage cell and/or the puck sequencing cells, and from the puck sequencing cells to the packaging cell or to the manual quality control station and back to the load cell. 
     In one operational embodiment, routing of pucks  402  is done using a plurality of multiple conveyors and part conveying techniques, with merge and divert units. In one example, with no intention to limit the invention, a first conveyor routs pucks from load cell  104  to sorting buffer cell  106  or exceptions handling cell  108  and back to load cell  104 . The first conveyor includes merge and divert units to allow “no read” pucks to go to the manual quality control station. A second conveyor routs pucks  402  from sorting buffer cell  106  to incomplete case storage cell  112  and/or puck sequencing cell  114 . The second conveyor includes a plurality of merge and divert units. A first divert unit allows a puck  402  to go to one of two puck sequencing cells and a second divert unit allows pucks  402  to go to incomplete case storage cell  112 . A third conveyor routs pucks  402  from puck sequencing cell  114  to packaging ceil  116  or to exceptions handling cell  108  and back to load cell  104 . A third conveyor may include two merge units and one divert unit. The divert unit allows pucks  402  to go to either the load cell  104  or a second manual quality control station. The conveyors may ran at any appropriate speed, for example, at a speed of 60 feet per minute allowing for a puck throughput rate of at least 60 parts per minute on each conveyor. Conveyors and conveying techniques are well known and are available from, for example, FlexLink Systems, Inc. of Allentown, Pa. 
     While the present invention has been shown and described with reference to specific embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.