Abstract:
A method and apparatus for packaging parts in compartments of a carrier tape and affixing a cover tape over the carrier tape to trap the parts in the compartments. The method and apparatus provide for deflecting a flange of the carrier tape and sealing the cover tape to the deflected flange. The cover tape is tightened across the carrier tape when the carrier tape flange returns to its undeflected condition.

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 60/335,505, filed Oct. 31, 2001. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to an apparatus for packaging parts, which may be, for example, microprocessors, computer chips, circuit boards, or any other electrical or mechanical components, in the compartments of a carrier tape, and affixing a cover tape over the carrier tape to trap the parts in the compartments. More specifically, the invention relates to a method for pulling tight or tensioning the cover tape after it has been sealed to the carrier tape. 
     BACKGROUND OF THE INVENTION 
     Small parts, such as microprocessors, computer chips, circuit boards, or any other electrical or mechanical components are often packaged in carrier tape holding compartments. These compartments are then sealed with cover tape to ensure that the parts will not fall out of the compartments. During the cover tape sealing process, the cover tape may buckle or bow, which compromises the peel strength of the cover tape. Additionally, ripples or creases in the cover tape caused by such buckling or bowing may be mistaken during post-seal inspection as a “sealing perimeter” or “part” defect, which can result in a rejection of a good part due to poor packaging. 
     SUMMARY OF THE INVENTION 
     The invention provides a method for attaching cover tape to carrier tape having side flanges and compartments between the side flanges. The method includes bending at least one of the side flanges of the carrier tape upward as the cover tape is bonded to both side flanges, and then releasing the bent flange once the cover tape is bonded to the flanges. The released flange returns to a flat orientation, which creates a tension in the cover tape, and ensures a tight fit of the cover tape over the compartments of the carrier tape. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of an inspection, handling, and packaging apparatus of the type with which this invention is usable. 
     FIG. 2 is a top view of the inspection, handling, and packaging apparatus of FIG. 1 along line  2 — 2 . 
     FIG. 3 is a perspective view of a portion of a carrier tape. 
     FIG. 4 is a section view, along line  4 — 4  in FIG.  1 . 
     FIG. 5 is a section view, along line  5 — 5  in FIG.  1 . 
    
    
     Before 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 arrangement of components or steps 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 other 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. 
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIGS. 1 and 2 illustrate an inspection, handling, and packaging apparatus  20  that includes a support stand  24 , an infeed carrier tape drive wheel  26 , a pick-and-place head or transport  28 , a carrier tape infeed reel  32  dispensing carrier tape  34 , a camera-over-tape or “COT” inspection module  36 , a cover tape reel  40  dispensing cover tape  41 , a sealing shoe  44 , a resilient drive roller  48 , a backup wheel  50 , a camera-after-sealing inspection module or “CASI” module  52 , and an output reel packaging module  56 . 
     The support stand  24  supports a plurality of part input trays  60  that contain parts  64  to be inspected and packaged. The parts  64  may be, for example, microprocessors, computer chips, circuit boards, or any other electrical or mechanical components. The transport  28  picks the parts  64  off the input trays  60 , and transfers the parts  64  to the carrier tape  34 . The transport  28  is preferably a pick-and-place type transport utilizing a vacuum head. 
     The carrier tape  34  is best illustrated in FIG. 3, and includes a pair of flanges  72  running along its length, and compartments  76  formed between the flanges  72 . One or both of the flanges  72  may include sprocket holes  80  to facilitate advancing the carrier tape  34  through the apparatus  20  and/or other machinery. For example, the infeed carrier tape drive wheel  26  may be a pinwheel having sprocket pins that engage the sprocket holes  80  of the carrier tape  34 . The drive wheel  26  may be driven under power by a motor (not illustrated) to pull the carrier tape  34  off the infeed reel  32 . Alternatively, the drive wheel  26  may have a smooth or flat surface and/or be passive or not driven by a motor. 
     The resilient drive roller  48  rotates under the power of a motor (not illustrated) to pull the carrier tape  34  through the apparatus  20  in a downstream direction  82  (an upstream direction being opposite the downstream direction  82 ). The flanges  72  of the carrier tape  34  are pinched between the drive roller  48  and the backup wheel  50  to facilitate the advancement of the carrier tape  34  under the influence of the rotating drive roller  48 . Alternatively, the drive roller  48  may include pins that engage the sprocket holes  80  in the tape flanges  72  to facilitate advancing the carrier tape  34  through the apparatus  20 . The carrier tape  34  is supported at its flanges  72  by guide rails  84  (FIGS. 1,  4 , and  5 ) that extend substantially the entire length of the apparatus  20 . 
     Referring again to FIGS. 1 and 2, the transport  28  places a single part  64  into each compartment  76  of the carrier tape  34 . The COT inspection module  36  is downstream of the transport  28 , and includes a camera, which inspects the parts  64  in the carrier tape compartments  76  as the carrier tape  34  is advanced through the apparatus  20 . 
     The cover tape  41  is laid on top of the carrier tape  34  downstream of the COT inspection module  36 , and is pulled through the apparatus  20  along with the carrier tape  34 . The cover tape  41  is guided from the cover tape reel  40  to the carrier tape  34  by a plurality of tensioning rollers  92 . The cover tape  41  extends between the flanges  72  and completely covers the compartments  76 . The adhesive, which is on the cover tape  41  surface, faces the carrier tape  34 . Heat activated cover tape has adhesive across the complete cover tape surface. Pressure sensitive activated cover tape has only two strips of adhesive that are located over the flanges  72  of the carrier tape  34 . The adhesive is used to seal the cover tape  41  to the flanges  72  of the carrier tape  34 . 
     Referring now to FIGS. 1,  2 , and  4 , the sealing shoe  44  is downstream  82  of the last tension roller  92 . The sealing shoe  44  includes a sealing mechanism  108  that is either a spool-shaped wheel or longitudinal flat shoe. The sealing mechanism  108  has flanges or edges  109  aligned over the flanges  72  of the carrier tape  34 , and in alignment with the lines of adhesive on the cover tape  41  if pressure sensitive adhesive is used. The wheel of the sealing mechanism  108  may be rotated under power or may passively roll as the tape  34 ,  41  passes under it. 
     A downward force is applied to the sealing mechanism  108  to pinch the cover tape  41  and carrier tape  34  together between the sealing flanges  109  and the guide rails  84 . The portion  112  of at least one of the guide rails  84  under the shoe  44  includes an angled surface or a ramp  116  for the associated flange  72  to ride up. Although one guide rail  84  is ramped in the illustrated construction, both guide rails  84  can be tapered toward the sealing mechanism  108  and still be within the scope of the invention. The flange  72  and cover tape  41  are therefore bent or angled up toward the shoe  44  as the bonding process occurs. The edge of the flange  109  over the ramp  116  is angled to complement the angle of the ramp  116  and to facilitate bonding. If heat is required to activate the adhesive, heating elements  118  (FIG. 4) may be inserted into the portions  112  of the guide rails  84  under the sealing shoe  44  for that purpose. 
     With reference to FIG. 5, the guide rails  84  are substantially flat downstream  82  of the sealing shoe  44 . The carrier tape  34  is sufficiently resilient to be bent up under the shoe, and spring back to the flat condition illustrated in FIG.  5 . As the carrier tape  34  springs back to this flat condition, the cover tape  41  is pulled tight across the compartments  76 , and assumes a substantially flat, planar orientation. In this flat, planar orientation, there is some tension in the cover tape  41  which causes any wrinkles in the cover tape  41  to be flattened out. 
     Referring back to FIGS. 1 and 2, the CASI module  52  is downstream  82  of the sealing shoe  44  and includes a camera that looks down at the tape  34 ,  41  and inspects the sealing bonding process for possible sealing shoe position errors or inconsistent sealing perimeters. Flattening the cover tape  41  as described above helps to reduce false rejections by the CASI module  52 . Such false rejections may be caused by the camera of the CASI module  52  mistaking wrinkles in the cover tape  41  as flaws. Also, the tightness of the cover tape  41  on the carrier tape  34  reduces the pull strength values that are tested on Peel Strength Analyzers with customers&#39; tape-and-reel processes. 
     The loaded carrier tape  34  is then wound onto the output reel-packaging module  56 . The apparatus  20  also includes a processor (not illustrated) that receives information from the COT and CASI modules  36 ,  52 . The processor has memory that records which of the parts  64  have been indicated by the inspection modules  36 ,  52  as having flaws. The flawed tape sealing process or bad parts in tape are later reviewed and, within another operational processes, the good parts  64  are taken from the carrier tape  34  for their end use.