Patent Publication Number: US-2005139450-A1

Title: Electrical part processing unit

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application claims priority from Provisional Application No. 60/533,463 filed Dec. 30, 2003 for “Electrical Part Processing Unit” by Merlin E. Behnke. 
    
    
     BACKGROUND OF THE INVENTION  
      The present invention relates to apparatuses for packaging electrical parts and, more particularly, to apparatuses for singulating electrical parts and methods of operating the apparatuses.  
      A variety of packaging apparatus are used to package electrical parts such as electronic computer chips, microprocessors, and the like. A group of electrical parts are fed to a part tray or tooling track of the packaging apparatus. Such packaging apparatuses include infeed part heads for vertically picking up the electrical parts from the horizontal electrical part tray, or tooling track, and placing the electrical parts vertically downward into a horizontal carrier tape or some other horizontal packaging device. The packaging apparatuses also include a linear actuator for linearly moving the part head between the tray or track and the carrier tape. Typically, the part head is vacuum operated and includes a vacuum nozzle for picking up the electrical part.  
     SUMMARY OF THE INVENTION  
      In one embodiment, the invention provides a part singulator mechanism for spacing parts along a path. The part singulator mechanism includes a path defined by a track and a drive mechanism. The part singulator mechanism also includes at least one first stopping member interconnected with the drive mechanism and positioned adjacent the path, the first stopping members are movable between a first position extended into the path and a second position retracted from the path. In addition, the part singulator mechanism includes at least one second stopping member interconnected with the drive mechanism and positioned adjacent the path, the second stopping members are movable between a first position extended into the path and a second position retracted from the path. The first stopping members and the second stopping members are arranged in an alternating sequence along the path. When the first stopping members are in the first position, the second stopping members are in the second position, and when the first stopping members are in the second position, the second stopping members are in the first position.  
      In another embodiment, the invention provides a part singulator mechanism for spacing parts along a path. The part singulator mechanism includes a path defined by a track; a drive mechanism including a first cam member and a second cam member; a plurality of first stopping members interconnected with the first cam member and positioned adjacent the path, the first stopping members being movable between a first position extended into the path and a second position retracted from the path; and a plurality of second stopping members interconnected with the second cam member and positioned adjacent the path, the second stopping members being movable between a first position extended into the path and a second position retracted from the path. The first stopping members and the second stopping members are arranged in an alternating sequence along the path. The first and second cam members are about 180° out of phase with each other such that when the first stopping members are in the first position, the second stopping members are in the second position, and when the first stopping members are in the second position, the second stopping members are in the first position.  
      In yet another embodiment, the invention provides a method of singluating a plurality of parts and spacing the parts a selected distance along a path. The method includes feeding a line of parts along a track to a singulating station wherein the track defines a path, stopping a first part in the line of parts at a first stopping member positioned in the path, and stopping a second part adjacent and upstream of the first part in the line of parts upstream from the first stopping member wherein the second part is stopped by a stopping mechanism. The first stopping member is removed from the path to permit the first part to advance along the path whereby the first part is stopped at a second stopping member positioned in the path. Substantially simultaneously with the first part stopping at the second stopping member, the second part is released from the stopping mechanism to permit the second part to advance along the path, and the first stopping member is moved into the path to stop the second part.  
      In a further embodiment, the invention provides a method for singluating a plurality of parts along a path. The method includes driving a plurality of first stopping members positioned adjacent the path between a first position extended into the path and a second position retracted from the path, and driving a plurality of second stopping members positioned adjacent the path between the second position and the first position. The first stopping members and the second stopping members are arranged in an alternating sequence. When the first stopping members are in the first position, the second stopping members are in the second position, and when the first stopping members are in the second position, the second stopping members are in the first position. The method further includes feeding a line of parts along the path upstream of the first and second stopping members, stopping a first part in the line of parts at a leading first stopping member in the first position, and stopping a second part that is adjacent and upstream of the first part in the line of parts upstream of the first and second stopping members to prevent further advancement of the line of parts. The leading first stopping member is moved to the second position to permit the first part to advance along the path, and the first part is stopped at a leading second stopping member in the first position. Next, the leading second stopping member is moved to the second position to permit the first part to advance along the path. Substantially simultaneously, the first part is stopped at a subsequent first stopping member in the first position and the second part is released and advanced to the leading first stopping member in the first position.  
      Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a side view of an electrical part processing unit embodying aspects of the present invention.  
       FIG. 2  is a cross-sectional view of an infeed track of the part processing unit taken along line  2 - 2  in  FIG. 1 .  
       FIG. 3  is a cross-sectional view similar to the cross-sectional view taken along line  2 - 2  of an alternative construction of an infeed track of the part processing unit.  
       FIG. 4  is a cross-sectional view similar to the cross-sectional view taken along line  2 - 2  of another alternative construction of an infeed track of the part processing unit.  
       FIG. 5  is a partial cross-sectional view of an electrical part singulator mechanism of the part processing unit shown in  FIG. 1  in a first singulating position.  
       FIG. 6  is a partial cross-sectional view of the singulator mechanism shown in  FIG. 5  in a second singulating position.  
       FIG. 7  is a partial cross-sectional view of the singulator mechanism shown in  FIG. 5  in a third singulating position.  
       FIG. 8  is a partial cross-sectional view of the singulator mechanism shown in  FIG. 5  in a fourth singulating position.  
       FIGS. 9-14  are side views of a pick-and-place (PNP) assembly of the processing unit shown in  FIG. 1 , shown in multiple operating positions.  
       FIGS. 15-18  are each side views of alternative constructions of an electrical part handling mechanism of the processing unit shown in  FIG. 1 , all shown without a PNP assembly. 
    
    
      Before at least one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and variations thereof herein are used broadly and encompass direct and indirect connections and couplings. In addition, the terms “connected” and “coupled” and variations thereof are not restricted to physical or mechanical connections or couplings.  
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       FIG. 1  illustrates an electrical part processing unit  20  for packaging and/or inspecting electrical parts  24 . The processing unit  20  includes an infeed tooling track  28  on which electrical parts  24  are introduced into the processing unit  20 . In the illustrated embodiment, the infeed track  28  is substantially vertically oriented and a line of electrical parts  24  are advanced downstream along the infeed track  28  under the force of gravity from a feed end  30  of the processing unit  20 . In further embodiments of the invention, the infeed track  28  is oriented in a position other than vertical, such as, for example inclined with respect to horizontal, to feed the electrical parts  24  downstream under the force of gravity.  
       FIG. 2  illustrates a cross-sectional view of the infeed track  28 . The infeed track  28  includes a pair of side walls  32 , a flange  36  extending inwardly at one end of each side wall  32 , and a base wall  38  connecting the opposite ends of side walls  32 . The parts  24  advance along the base wall  38  of the infeed track  28 . The flanges  36  capture the electrical parts  24  between the base wall  38  and the flanges  36  to prevent the electrical parts  24  from falling off the infeed track  28  or from stacking upon other electrical parts  24  within the infeed track  28 .  
      With reference to  FIG. 3 , an alternative embodiment of the infeed track  28  is illustrated. The infeed track  28  includes a pair of side walls  32  and a base wall  38 . In this embodiment, the infeed track  28  is inclined to support the electrical parts  24  on the track  28  from underneath, or the infeed track  28  includes a track vacuum operable to vacuumly secure the electrical parts  24  to the infeed track  28  in order to prevent the electrical parts  24  from falling off the infeed track  28 . In constructions where the infeed track  28  includes a track vacuum, the track vacuum is utilized to advance the electrical parts  24  downstream along the infeed track  28  whereby the track vacuum is used in combination with gravity to assist in advancing the electrical parts  24  downstream.  
      With reference to  FIG. 4 , another alternative embodiment of the infeed track  28  is illustrated. The infeed track  28  includes side walls  32 , a base wall  38  and a top wall  39  to completely surround the electrical part  24 . In this embodiment, the electrical part  24  is surrounded on all sides to prevent the electrical part from falling off the infeed track  28  or from stacking upon other electrical parts  24 .  
      With reference to  FIGS. 1 and 5 - 8 , the processing unit  20  includes an electrical part singulator mechanism  40  for singulating the electrical parts  24  and spacing the parts  24  along the infeed track  28 . The singulator mechanism  40  includes a drive mechanism  44 , a first support member  48 , and a second support member  52 . In the illustrated embodiment, the first support member  48  is positioned forward of the second support member  52  with respect to the drive mechanism  44 , however, in further embodiments of the invention the first support member may be positioned rearward to or adjacent with the second support member. In the illustrated embodiment, the drive mechanism  44  is either a servo motor or a stepper motor.  
      The drive mechanism  44  includes a first cam member  56  and a second cam member  60 , which are about 180° out of phase with each other. The first cam member  56  cams against the first support member  48  to move the first support member  48  relative to the infeed track  28  and the second cam member  60  cams against the second support member  52  to move the second support member  52  relative to the infeed track  28 . Biasing members bias the first and second support members  48 ,  52  against the respective first and second cam members  56 ,  60 . The first and second support members  48 ,  52  may therefore be considered cam followers. In further embodiments, other drive means may be used to move the first and second support members  48 ,  52  with respect to the infeed track  28 .  
      The first and second support members  48 ,  52  each include a plurality of respective first and second stopping members  64 ,  68  that extend into and through the infeed track  28 . The second stopping members  68  also extend through the first support member  48  in the illustrated construction. Rotational movement of the first and second cam members  56 ,  60  is converted into reciprocal movement of the first and second stopping members  64 ,  68  as the first and second support members  48 ,  52  follow the cam profiles of the first and second cam members  56 ,  60 . The range of motion of the first and second support members and stopping members  48 ,  52 ,  64 ,  68  is between a first or extended position and a second or retracted position.  
       FIG. 5  illustrates the first support and stopping members  48 ,  64  in the extended position, and  FIG. 7  illustrates the second support and stopping members  52 ,  68  in the extended position. The stopping members  64  or  68  in the extended position are extend into the electrical parts path defined by the infeed track  28  and obstruct the movement of parts  24  along the track  28 .  FIG. 5  illustrates the first support and stopping members  48 ,  64  in the retracted position, and  FIG. 7  illustrates the second support and stopping members  52 ,  68  in the retracted position. The stopping members  64  or  68  in the retracted position are withdrawn from the electrical parts path defined by the infeed track  28 , and parts  24  are permitted to slide along the track past the retracted stopping members  64  or  68 .  
      Because of the first and second support members are essentially cam followers, rotation of the cam members  56 ,  60  cyclically (and about 180° out of phase with each other) push the respective first and second support members  48 ,  52  and their respective stopping members  64 ,  68  toward the extended position against the biasing force, and permit the respective support members  48 ,  52  and associated stopping members  64 ,  68  to move under the biasing force toward the retracted position.  
      The first and second stopping members  64 ,  68  are positioned in an alternating sequence within the singulator mechanism  40 , as shown in  FIG. 5 . Each of the stopping members  64 ,  68  extend through a bearing  72  positioned in the infeed track  28 . The bearings  72  ease movement of the stopping members  64 ,  68  relative to the infeed track  28 . Although in the illustrated embodiment, the first stopping members  64  are moveable in unison with one another and the second stopping members  68  are movable in unison with one another, it is within the scope of the invention to provide independent actuating means for each stopping member  64 ,  68 . In the illustrated embodiment, the stopping members are pins, however, those skilled in the art will recognize that other stopping means may be used to extend and retract with respect to the infeed track and stop movement of electrical parts along the track. Although multiple first and second stopping members are shown in the illustrated embodiment, a minimum of two stopping members may be used in the invention.  
      The singulator mechanism  40  also includes a stopping mechanism  76  for stopping the line of electrical parts  24  positioned upstream of the first and second stopping members  64 ,  68 . In the illustrated embodiment, the stopping mechanism  76  is a stop pin  80  that may operate in response to rotation of the cam members  56 ,  60  or have its own cam or other actuating mechanism. The stopping mechanism  76  engages a second electrical part  24 B in the line of electrical parts  24  to force the second electrical part  24 B against the infeed track  28 . Such engagement prevents downstream movement of the second electrical part  24 B and the electrical parts  24  upstream of the second electrical part  24 B. In a further embodiment of the invention, the stopping mechanism  76  may incorporate a vacuum mechanism operable to hold with vacuum pressure the second electrical part  24 B against the track  28 , and thereby prevent downstream movement of the second electrical part  24 B and the electrical parts  24  upstream of the second electrical part  24 B. In the illustrated embodiment, the stopping mechanism is a pin, however, those skilled in the art will recognize that other stopping means may be used to extend and retract with respect to the infeed track and stop movement of electrical parts along the track.  
      Referring back to  FIG. 1 , the processing unit  20  also includes a first inspection unit  84  for inspecting a top surface of the electrical parts  24 . In the illustrated embodiment, the first inspection unit  84  is positioned downstream of the singulator mechanism  40 . In further embodiments, the first inspection unit  84  is positioned upstream of the singulator mechanism  40  or in the same position as the singulator mechanism  40  to inspect the electrical parts  40  as they pass through the singulator mechanism  40 . In operation, the first inspection unit  84  is electrically connected to a controller  88  of the processing unit  20 . The controller  88  is operable to control multiple aspects of the processing unit  20 . The first inspection unit  84  relays to the controller  88  whether the top surfaces of the electrical parts  24  are acceptable or unacceptable.  
      With reference to  FIGS. 1 and 9 - 14 , the processing unit  20  also includes a part positioning mechanism  92  positioned downstream of the singulator mechanism  40 . In the illustrated embodiment, the part positioning mechanism  92  is in-line with the infeed track  28  and stops the leading electrical part  24 A along the infeed track  28  adjacent a pick-and-place (PNP) assembly  100  (discussed below). The illustrated part positioning mechanism  92  includes a vacuum portion  96  that secures the leading electrical part  24 A using vacuum pressure in a position to be engaged by the PNP assembly  100 .  
      The part positioning mechanism  92  is rotateable into and out of alignment with the infeed track  28  and into and out of engagement with the leading electrical part  24 A to release the leading electrical part  24 A from the vacuum portion  96  of the part positioning mechanism  92 . In further embodiments, the part positioning mechanism  92  is moveable in manners other than rotation, such as by linear translation. In another embodiment, the part positioning mechanism  92  includes a moveable member that engages the leading electrical part  24 A to stop and position the leading electrical part  24 A in position along the infeed track  28 . The moveable member can be moved in a variety of manners, such as, for example pneumatically, spring biased, cammed, etc. In yet another embodiment, the part positioning mechanism  92  is positioned out-of-line with the infeed track  28  and engages the leading electrical part  24 A to properly position the leading electrical part  24 A for engagement by the PNP assembly  100 .  
      With continued reference to  FIGS. 1 and 9 - 14 , the processing unit  20  further includes the PNP assembly  100 , which engages and removes a leading electrical part  24 A in the line of electrical parts  24  from the infeed track  28 . The PNP assembly  100 , has a spindle  104 , a pair of large cams  108 , a small cam  112 , and a PNP nozzle  116  connected to the spindle  104 . The large cams  108  and the small cam  112  are rotateably connected to the spindle  104  and rotate to move the spindle  104  (discussed below). The PNP nozzle  116  is connected to the end of the spindle  104  and is in fluid communication with a vacuum source (not shown). The PNP nozzle  116  is operable to engage the leading electrical part  24 A and vacuumly secure the leading electrical part  24 A thereto. In the illustrated embodiment, the spindle  104  is oriented substantially perpendicular to the infeed track  28  and is moveable toward and away from the infeed track  28  to engage the leading electrical part  24 A retained in position by the part positioning mechanism  92 . The PNP nozzle  116 , operable by the spindle  104 , removes the leading electrical part  24 A from the part positioning mechanism  92 , positions the leading electrical part  24 A for inspection, and places the leading electrical part  24 A in a downstream part handling mechanism  124  (discussed below).  
      With continued reference to  FIGS. 1 and 9 - 14 , the processing unit  20  further includes a second inspection unit  120  for inspecting sides and bottom surfaces of the electrical parts  24 . The second inspection unit  120  is electrically connected to the controller  88  to relay whether the sides and/or the bottom surfaces of the electrical parts  24  are acceptable or unacceptable. The second inspection unit  120  can be any inspection mechanism operable to inspect sides and the bottom surfaces of the electrical parts  24 .  
      The processing unit  20  further includes an electrical part handling mechanism  124  for receiving the electrical parts  24  from the PNP assembly  100  and advancing the electrical parts  24  downstream along the processing unit  20 . In the illustrated embodiment, the handling mechanism  124  is positioned downstream of the second inspection unit  120 . The handling mechanism  124  includes a rotateable arm  128  for receiving the electrical parts  24  from the PNP assembly  100  (discussed below) and rotating to deposit the electrical parts  24  into an empty compartment  140  of a carrier tape  132  or other packaging device.  
      Now that the components of the part processing unit  20  have been described, operation of the processing unit  20  will be described hereafter with respect to the processing of electrical parts  24 . In the processing unit  20  shown in  FIG. 1 , the electrical parts  24  are initially fed to the singulator mechanism  40 , shown in  FIGS. 5-8 , for singulating and spacing parts  24  along the infeed track  28 . The singulation process begins in  FIG. 5  with a line of electrical parts  24  being fed into the processing unit  20  along the infeed track  28 . In  FIG. 5 , the cams  56 ,  60  are in a first position designated by the reference letter A. The first cam  56  pushes the first support and stopping members  48 ,  64  into the extended position. The leading electrical part  24 A abuts the leading first stopping member  64  of the first support member  48 , which prevents downstream movement of the leading electrical part  24 A along the path. The second cam  60  permits the second support and stopping members  52 ,  68  to move into the retracted position. At this point, the stopping mechanism  76  is moved away from the infeed track  28  and does not abut against any electrical part  24  in the line of parts.  
      The drive mechanism  44  continues to rotate the cams  56 ,  60  to a second position, designated by reference letter B in  FIG. 6 . At this point during the singulation process, the stopping mechanism  76  abuts against the second electrical part  24 B in the line of electrical parts  24 . The stopping mechanism  76  holds the second electrical part  24 B against the infeed track  28  to prevent downstream movement of the electrical parts  24  upstream from the leading electrical part  24 A along the infeed track  28 . The first cam  56  now permits the first support member and stopping members  48 ,  64  to move toward the retracted position, and the second cam  60  moves the second support and stopping members  52 ,  68  towards the extended position.  
      In  FIG. 7 , the drive mechanism  44  rotates the first and second cam members  56 ,  60  to a third position, designated by reference letter C. The first cam member  56  now permits the first support and stopping members  48 ,  64  to move into the retracted position, and the second cam member  60  moves the second support and stopping members  52 ,  68  into the extended position. The leading electrical part  24 A advances downstream under the influence of gravity until it abuts the leading second stopping member  68 . The electrical parts  24  upstream of the leading electrical part  24 A are maintained in position by the stopping mechanism  76  that abuts against the second electrical part  24 B.  
       FIG. 8 , the drive mechanism  44  rotates the first and second cam members  56 ,  60  to a fourth position, designated by reference letter D. The first cam member  56  now moves the first support and stopping members  48 ,  64  toward the extended position, and the second cam member  60  permits the second support and stopping members  52 ,  68  to move toward the retracted position.  
      The drive mechanism  44  continues to rotate the first and second cam members  56 ,  60  to the first position shown in  FIG. 5 , which completes a cycle by positioning the first support and stopping members  48 ,  64  in the extended position and the second support and stopping members  52 ,  68  in the retracted position.  
      As the second stopping members  68  move toward the retracted position, the leading electrical part  24 A advances downstream under the force of gravity until it abuts against the subsequent first stopping member  64  in the extended position. Substantially simultaneously, the stopping mechanism  76  disengages the second electrical part  24 B, which moves downstream along the infeed track  28  under the influence of gravity until is abuts against the leading first stopping member  64  in the extended position. The distance between the first stopping members  64  therefore defines the spacing between the electrical parts  24  as the parts  24  advance along the infeed track  28 .  
      With reference to  FIGS. 5-8 , the drive mechanism  44  continuously rotates to move the first and second stopping members  64 ,  68  between the extended and retracted positions. The first and second support members  48 ,  52  and the stopping mechanism  76  continue to operate in the manner discussed above to advance electrical parts  24  along the infeed path  28  and simultaneously space the electrical parts  24  from one another. In the illustrated embodiment, and as a result of the 180° offset of the cam members  56 ,  60 , when the first stopping members  64  are extended into the infeed track  28  and into the path of the electrical parts  24 , i.e., the first position, the second stopping members  68  are retracted from the infeed path and out of the path of the electrical parts  24 , i.e., the second position. Further, when the second stopping members  68  are extended into the infeed track  28  and into the path of the electrical parts  24 , i.e., the first position, the first stopping members  64  are retracted from the infeed path and out of the path of the electrical parts  24 , i.e., the second position. Thus, the first and second stopping members  64 ,  68  alternately move between the first position and the second position. All electrical parts  24  within the singulator  40  are supported by only the first stopping members  64  (when they are in the extended position) or only by the second stopping members (when they are in the extened position), and alternate between the two as the parts are cycled through the singulator  40 .  
      It should be recognized by one of ordinary skill in the art that discussion of the rotation of the cam members is discussed in 90° increments for ease of description. It should also be recognized that fewer or more stopping members, or at least two first stopping members could be used to achieve the present invention.  
      Referring to  FIG. 1 , after the electrical parts  24  are singulated at the singulation mechanism  40 , the electrical parts  24  advance past the first inspection unit  84 . The first inspection unit  84  inspects the top surfaces of the electrical parts  24  and relays signals to the controller  88  relating to the acceptability or unacceptability of the electrical parts  24 .  
      After advancing past the inspection unit  84 , the electrical parts  24  advance downstream along the track  28  to the part positioning mechanism  92 , which individually engages the electrical parts. The electrical parts  24  are stopped along the track  28  by vacuum pressure from the vacuum portion  96  (shown in  FIG. 10 ) of the part positioning mechanism  92 . The part positioning mechanism  92  stops the electrical parts  24  in a position that allows the PNP assembly  100  to engage the electrical parts  24  and remove the electrical parts  24  from the track  28 .  
      In the embodiment shown in  FIG. 1 , the PNP assembly  100  is recessed from the inspection unit  120  and positioned between the part positioning mechanism  92  and the part handling mechanism  124 . The rotateable arm  128  of the part handling mechanism  124  is positioned adjacent the PNP assembly  100 . The two large cams  108  rotate to move the PNP nozzle  116  at the end of spindle  104  toward the electrical part  24  stopped along the track  28  by the part positioning mechanism  92 , as shown in  FIG. 9 . In the illustrated embodiment, the rotateable arm  128  of the part handling mechanism rotates substantially simultaneously towards the carrier tape  132 , often with an electrical part attached thereto.  
      As shown in  FIG. 10 , the two large cams  108  continue to rotate to move the spindle  104  and the PNP nozzle  116  toward the electrical part  24 . The spindle  104  includes a cam surface  136  that abuts the part positioning mechanism  92  to thereby rotate the part positioning mechanism  92  to an open position. Substantially simultaneously, the vacuum of the part positioning mechanism  92  turns off to release the electrical part  24  and the PNP nozzle  116  vacuumly secures the electrical part  24  thereto. In the illustrated embodiment, the rotateable arm  128  of the part handling mechanism rotates substantially simultaneously to the carrier tape  132  for depositing an electrical part in the empty compartment  140 .  
      In  FIG. 11 , the large cams  108  continue to rotate to move the spindle  104 , the PNP nozzle  116 , and the electrical part  24  vacuumly secured to the PNP nozzle  116  to a position adjacent the second inspection unit  120 . The PNP nozzle  116  is positioned between the part positioning mechanism  92  and the part handling mechanism  124  adjacent the inspection unit  120 . The cam surface  136  releases the part positioning mechanism  92  and the part positioning mechanism  92  rotates back to the original position.  
      In  FIG. 12 , the large cams  108  cease rotating and the small cam  112  rotates to move the spindle  104  toward the inspection unit  120 . Resultantly, the electrical part  24  and a portion of the PNP nozzle  116  enter the inspection unit  120 . Inspection of the side walls and the bottom surface of the electrical part  24  occurs within the inspection unit  120 , which relays signals to the controller  88  relating to the acceptability or unacceptability of the electrical part  24 . In the illustrated embodiment, the rotateable arm  128  of the part handling mechanism rotates substantially simultaneously away from the carrier tape  132 . In  FIG. 13 , the small cam  112  continues to rotate and moves the spindle  104  away from the inspection unit  120 , which resultantly removes the electrical part  24 A and the PNP nozzle  116  out of the inspection unit  120 . In the illustrated embodiment, the rotateable arm  128  of the part handling mechanism  124  rotates substantially simultaneously back to its original position for receiving an electrical part  24 .  
      In  FIG. 14 , the small cam  112  ceases rotating and the large cams  108  resume rotating to move the electrical part  24  vacuumly secured to the PNP nozzle  116  toward the part handling mechanism  124 . Once the electrical part  24  is engaged with the part handling mechanism  124 , the PNP nozzle  116  vacuum is turned off. Substantially simultaneously, the vacuum of the part handling mechanism  124  is turned on in order to remove the electrical part  24  from the PNP nozzle  116  and vacuumly secure the electrical part  24  to the part handling mechanism  124 . The large cams  108  continue to rotate and move the spindle  104  shown in  FIG. 1  to complete one cycle of the PNP process. The PNP process then resumes to pick another electrical part  24  from the track  28  for inspection by inspection unit  120 .  
      During the PNP process described above and shown in  FIGS. 1 and 9 - 14 , the rotateable arm  128  of the part handling mechanism  124  picks an electrical part  24  from the PNP nozzle  116  and rotates toward the carrier tape  132  to position the electrical part  24  into a compartment  140 . Once the electrical part  24  is positioned in the compartment  140  of the carrier tape  132 , the vacuum of the part handling mechanism  124  is turned off and the electrical part  24  is released into the compartment  140 . The rotateable arm  128  then rotates upward to receive the next electrical part  24  and the carrier tape  132  advances to align an empty compartment  140  with the rotateable arm  128  for receiving the next electrical part  24 . This operation is repeated for each electrical part  24  advancing through the processing unit  20 .  
       FIG. 15  illustrates an alternative construction of a part handling mechanism  144 . The part handling mechanism  144  includes a dropping mechanism  146  which rotates about a pivot point  148  to position the electrical part  24  over the carrier tape  132  and drop the electrical part  24  into the carrier tape  132 . Such a part handling mechanism with a dropping mechanism is disclosed in co-pending U.S. patent application Ser. No. 10/239,344, filed on Sep. 21, 2002.  
       FIG. 16  illustrates another alternative construction of a part handling mechanism  152 . The part handling mechanism  152  includes a rotateable PNP vacuum nozzle  154  (similar to the PNP nozzle  116  of the PNP assembly  100 ). The part handling mechanism  152  removes the electrical parts  24  from the track  28  by vacuumly securing the electrical parts  24  to the PNP vacuum nozzle  154 . After the electrical part  24  is secured to the PNP vacuum nozzle  154 , the PNP vacuum nozzle  154  rotates to position the electrical part  24  over carrier tape  132 . The PNP vacuum nozzle  154  then turns off the vacuum supplied to the PNP vacuum nozzle  154  to place the electrical part  24  in the carrier tape  132 .  
       FIG. 17  illustrates yet another alternative construction of a part handling mechanism  156 . The part handling mechanism  156  includes a rotateable multi-vacuum nozzle assembly  158 . In the illustrated embodiment, the assembly  158  includes four vacuum nozzles  160 , however in further embodiments of the assembly  158  any number of vacuum nozzles  160  can be included. Multiple vacuum nozzles  160  allow the assembly  158  to place electrical parts  24  into the carrier tape  132  much quicker than if the assembly  158  included only one vacuum nozzle.  
      The multi-vacuum nozzle assembly  158  is operable to subject the electrical parts  24  to additional processing steps prior to being placed into the carrier tape  132 , such as other inspection operations, rejection of electrical parts, etc. In such constructions, each vacuum nozzle  160  vacuumly secures an electrical part  24  thereto and rotates counter-clockwise (as viewed in  FIG. 17 ). The electrical parts  24  are subjected to further processing steps anywhere between being initially secured to the vacuum nozzles  160  and placing the electrical parts  24  in the carrier tape  132 . Preferably, further processing steps occur at the top dead center location of the assembly  158  (above the upper vacuum nozzle  160  in  FIG. 17 ) and at the far left location of the assembly  158  (to the left of the left most vacuum nozzle  160  in  FIG. 17 ).  
       FIG. 18  illustrates an alternative construction of the part positioning mechanism and the part handling mechanism  156  shown in  FIG. 17 . The part handling mechanism includes the rotateable multi-vacuum nozzle assembly  158  similar to the rotateable multi-vacuum nozzle assembly described above with respect to  FIG. 17 . In this embodiment, the second inspection unit  120  is positioned at the top dead center location of the assembly  158 , an output track  164  is positioned at the left most location of the assembly  158 , and the carrier tape  132  is positioned at the bottom dead center location of the assembly  158 .  
      Operation of the assembly  156  illustrated in  FIG. 18  will be described with respect to one electrical part  24  as it advances through the processing unit  20 . A vacuum nozzle  160  positioned near the infeed track  28  vacuumly secures an electrical part  24  thereto. The assembly  158  then rotates counter-clockwise to position the electrical part  24  adjacent the second inspection unit  120 . The vacuum nozzle  160 , with the electrical part  24  attached thereto, extends to plunge the electrical part  24  into the second inspection unit  120 . After the electrical part  24  is properly inspected, the vacuum nozzle  160  retracts to remove the electrical part  24  from the second inspection unit  120 .  
      The assembly  158  then rotates to position the electrical part  24  near the output track  164 . In one embodiment, the output track  164  feeds the electrical part  24  to supporting devices (not shown) other than the carrier tape  132  in order to package the electrical parts  24  in the supporting devices, such as tubes, trays, etc. If the electrical part  24  is identified for being packaged in such supporting devices, the vacuum nozzle  160  extends to the output track  164  and releases the electrical part  24  to the output track  164 . The output track  164  includes a vacuum and vacuumly secures the electrical part  24  thereto. Preferably, the vacuum nozzle  160  turns off the vacuum supply thereto substantially simultaneously with the vacuum of the output track  164  turning on.  
      In another embodiment, the output track  164  is a reject track and feeds electrical parts  24  that are identified as unacceptable by the inspection units  84 ,  120  to a rejection mechanism (not shown). If the electrical part  24  is identified as unacceptable, the vacuum nozzle  160  extends to the output track  164  and releases the electrical part  24  to the output track  164 . The output track  164  includes a vacuum and vacuumly secures the electrical part  24  thereto. Preferably, the vacuum nozzle  160  turns off the vacuum supply thereto substantially simultaneously with the vacuum of the output track  164  turning on.  
      Whether or not the electrical part  24  is placed on the output track  164 , the assembly  158  rotates to position the vacuum nozzle  160  near the carrier tape  132 . If the electrical part  24  was placed on the output track  164 , nothing happens at this location. However, if the electrical part  24  was not placed on the output track  164 , the vacuum nozzle  160  extends to position the electrical part  24  in a compartment (not shown) of the carrier tape  132 . The vacuum of the vacuum nozzle  160  is turned off to release the electrical part  24  into the carrier tape  132 . This operation is repeated for each electrical part  24  advancing through the processing unit  20 .  
      The operation of the part processing unit described above is controlled by the controller  88  to ensure a steady flow of electrical parts  24  through the part processing unit  20 . In some embodiments, the drive mechanism  44 , the large cams  108  and the small cam  112  of the PNP assembly  100  are mechanically connected and controlled together by the controller  88 . The controller  88  properly times the drive mechanism  44  and the cams  108 ,  112  with respect to one another to ensure a steady flow of electrical parts  24  through the processing unit  20 . In further embodiments, the drive mechanism  44  and the cams  108 ,  112  are not mechanically connected and may be driven independently of each other. In these embodiments, the controller  88  is connected independently to the drive mechanism  44  and the cams  108 ,  112  to properly time them with respect to one another and ensure a steady flow of electrical parts  24  through the processing unit  20 .  
      It should be understood that the part processing units described above are described with respect to a single infeed track  28 , a single part singulating mechanism  40 , a single first inspection unit  84 , a single second inspection unit  120 , a single part positioning mechanism  92 , a single PNP assembly  100  and a single part handling mechanism  124 . However, it should be understood that the PNP assembly  100  can include multiple spindles  104 , multiple sets of large and small cams  108 ,  112 , and multiple PNP nozzles  116  in order to vacuumly secure a plurality of electrical parts  24  thereto rather than a single electrical part  24 . Accordingly, the part processing unit  20  can also include multiple infeed tracks  28 , multiple part singulating mechanisms  40 , multiple inspections units  84 ,  120 , multiple handling mechanisms  124 , and/or multiple electrical part supporting devices such as carrier tape, tubes, etc. to accommodate such a PNP assembly  100 . It should also be understood that the multiple spindles  104  of such a PNP assembly  100  are operable in unison to pick up electrical parts  24  simultaneously or operable independently of one another.  
      It should be further understood that the PNP assembly  100  can include any number of vacuum nozzles  116 . In such embodiments, the vacuum nozzles  116  are connected to a single spindle  104  and moved in unison with each other or are connected to separate spindles  104 , and either be moved in unison with each other or moved independently from each other.  
      It should be further understood that the PNP nozzles  116 ,  160  can be any shape and size to pick-up any shape and size of electrical part  24 . In addition, the PNP nozzles  116 ,  160  can be made of a variety of appropriate materials for picking up electrical parts  24 .  
      Although particular constructions of the present invention have been shown and described, other alternative constructions will be apparent to those skilled in the art and are within the intended scope of the present invention.