1. Field of the Invention
The present invention relates generally to the manufacture and assembly of electronic, mechanical, or electromechanical components comprised of various small devices such as bare semiconductor die, packaged semiconductor die, lead frames, other electronic devices, small mechanical parts, or any combination thereof More particularly, the present invention relates to the supply and handling of small devices on a carrier tape and, specifically, to an apparatus and method for recycling the carrier tape after removal of the devices carried thereon.
2. State of the Art
Electronic, mechanical, and electromechanical components are commonly manufactured using fully, or at least partially, automated manufacturing systems. Complex assemblies, such as, for example, multichip memory modules, motherboards, and other control modules, are often comprised of numerousxe2x80x94and, in some instances, dozens ofxe2x80x94bare and/or packaged semiconductor die as well as other electronic devices such as resistors, capacitors, heat sinks, and LEDs. Further, the numerous parts or subassemblies that are incorporated into a complex electrical or mechanical component may be of greatly varying size and shape. Thus, for many applications, a critical facet of automated manufacturing is the supply and handling of discrete parts for assembly into a next-level component.
A common method for supplying and handling large numbers of discrete parts in automated manufacturing systems is to employ a carrier tape. Referring to FIGS. 1 and 2, a typical carrier tape 10 comprises a continuous tape 12 having one or more rows of pockets 14 disposed thereon. The pockets 14 are each configured to receive a particular part such as, for example, a bare semiconductor die, a packaged semiconductor die, a lead frame, an electronic device, or a small mechanical part. Each pocket 14 may include an aperture 15 for passage therethrough of a push-out pin for extracting a part resting within the pocket 14. One or more raised portions 16 may be disposed in each pocket 14 for supporting a part resting therein. Disposed proximate each edge 13 of the continuous tape 12 is one or more rows of indexing holes 18. The indexing holes 18 may be of any suitable shape, such as, for example, circular 18a or rectangular 18b. 
The configuration of the carrier tape 10 shown in FIGS. 1 and 2 is only exemplary and numerous other carrier tape configurations are known in the art. For example, a carrier tape 10 may include multiple rows of pockets 14, multiple rows of indexing holes 18 adjacent each edge 13, or indexing holes 18 arranged along only one edge 13. The carrier tape 10 may also include a protective covering (not shown) adhered to the top surface of the continuous tape 12 to protect parts disposed in the pockets 14 prior to extraction. Carrier tape 10 is conventionally manufactured from a variety of plastic materials, such as, for example, a polycarbonate material, as well as from metallic materials.
A common medium for storing, transporting, and handling a plurality of parts borne on a length of carrier tape 10 is a tape reel. A typical tape reel 20 is shown in FIGS. 3 and 4. The tape reel 20 includes a hub 22 extending between and attached to opposing side plates 24. Each side plate 24 is disk-shaped and includes an outer circumferential edge 25 and an outer surface 26. The tape reel 20 has a thickness 21 corresponding to the distance between the outer surfaces 26 of the opposing side plates 24. Extending through the hub 22 and concentric with the axis of rotation 27 of the tape reel 20 is a shaft hole 28 configured for insertion of a shaft (not shown) therethrough to rotationally support the tape reel 20. To facilitate rotation of a tape reel 20, the shaft hole 28 may have a xe2x80x9ckeyxe2x80x9d shape, such as the three-prong shape shown in FIG. 3, enabling the tape reel 20 to be positively rotationally driven by a mating shaft. The tape reel 20 may further include a plurality of windows 29 disposed in the side plates 24 for viewing the quantity of carrier tape 10 wound on the hub 22. The configuration of the tape reel 20 shown in FIGS. 3 and 4 is only exemplary and other tape reel configurations are known in the art.
Automated manufacturing systems adapted for manipulating reels of carrier tape, and the parts disposed therein, are well-known in the art. Manufacturing systems adapted for removing parts from carrier tape 10 wound on a tape reel 20 generally include an extraction mechanism for removing the parts carried in the pockets 14 of the carrier tape 10 and a feed mechanism for feeding carrier tape 10 from a tape reel 20 to the extraction mechanism. A typical extraction mechanism includes an extraction head configured to remove a part from a pocket 14 of a carrier tape 10, as well as a push-out pin to assist in the extraction. An extraction head may comprise a vacuum quill, a mechanical gripping mechanism, or any other suitable extraction device known in the art.
Extraction of the parts borne on a carrier tape 10 requires that the pockets 14 arranged in a row along the length of the carrier tape 10 be sequentially positioned into a target location underneath or proximate the extraction head. Further, removal of a part from its respective pocket 14 on the carrier tape 10 generally requires that the pocket 14 be substantially aligned with the extraction head. The feed mechanism sequentially feeds, or indexes, the pockets 14 on a length of carrier tape 10 relative to the extraction head and aligns an individual pocket 14 therewith, using the indexing holes 18 of the carrier tape 10. A typical feed mechanism includes a plurality of indexing teethxe2x80x94arranged, for example, around an outer circumferential edge of a feed wheelxe2x80x94configured to closely mate with the row or rows of indexing holes 18 of the carrier tape 10. With one or more indexing teeth engaging each row of indexing holes 18 on a length of carrier tape 10, feeding and alignment of the pockets 14 on the carrier tape 10 relative to an extraction head is effected by movement of the indexing teeth. Feeding of the carrier tape 10 to the extraction mechanism, and precise alignment of a pocket 14 on the carrier tape 10 relative thereto, can be achieved so long as a close mating relationship exists between the indexing teeth of the feed mechanism and the carrier tape indexing holes 18. If the close mating fit between the indexing teeth and carrier tape indexing holes 18 is compromisedxe2x80x94for example, by damage to the carrier tape indexing holes 18xe2x80x94feeding and precise alignment of the carrier tape 10 relative to the extraction mechanism may no longer be possible.
After removal of the parts borne on a carrier tape, a typical automated manufacturing system feeds the emptied, or bare, carrier tape into a storage bin or receptacle. For some manufacturing systems, the bare carrier tape is simply allowed to collect on the floor of the manufacturing facility, presenting a potential safety hazard. The bare carrier tape is then disposed of as waste, resulting in a large quantity of plastic waste being discarded in landfills and other disposal sites, thereby creating an adverse environmental impact. As the manufacture and assembly of electronic, mechanical, and electromechanical components becomes increasingly automatedxe2x80x94especially in the semiconductor and electronics industriesxe2x80x94the amount of waste carrier tape disposed of will increase and, accordingly, the adverse environmental impact will grow.
Disposing of bare carrier tape as waste also increases manufacturing costs. A length of carrier tape is currently utilized only once during its lifetime; however, after removal of the parts borne on a length of carrier tape by an automated manufacturing system, the bare carrier tape may be essentially undamaged. It is believed that carrier tape may be reused so long as the integrity of the indexing holes of the carrier tape is maintained.
Accordingly, a need exists for an apparatus and method for retrieving carrier tape from a manufacturing system without damage to the carrier tape, enabling the carrier tape to be reused, and without adversely affecting operation of the manufacturing system.
Embodiments of the present invention comprise a carrier tape recycling apparatus configured for receiving bare carrier tape from multiple feed lines of a manufacturing system and for winding the carrier tape onto a plurality of tape reels for reuse. The carrier tape recycling apparatus comprises a housing, or frame, supporting a reel drive mechanism. The reel drive mechanism supports and rotationally drives one or more tape reels such that bare carrier tape dispensed from a manufacturing system may be wound onto the tape reels. The reel drive mechanism provides a slip drive, allowing each tape reel disposed in the recycling apparatus to rotatexe2x80x94or, in some instances, cease rotatingxe2x80x94and to receive carrier tape independent of the other tape reels disposed in the recycling apparatus. The slip drive, therefore, compensates for variation in carrier tape feed rate among multiple feed lines dispensing bare carrier tape from a manufacturing system, and the slip drive also prevents excessive tension from being imparted to the bare carrier tape as the carrier tape is wound onto a tape reel.
In an exemplary embodiment of the carrier tape recycling apparatus, the reel drive mechanism comprises one or more drive shafts and one or more guide shafts configured to cooperatively support and rotationally drive a plurality of tape reels. A tape reel disposed in the recycling apparatus is rotationally driven by frictional forces imparted to the outer circumferential edges of the tape reel by the outer circumferential surface, or drive surface, of the drive shaft or shafts in contact therewith. A plurality of guides disposed on the guide shaft or shafts provide lateral support for a tape reel disposed in the recycling apparatus while permitting the tape reel to rotate. The respective positions of the guide shaft or shafts and associated guides may be altered to configure the recycling apparatus for use with varying sizes and numbers of tape reels. The reel drive mechanism further includes a drive motor to rotationally drive the drive shafts and tape reels in contact therewith. A drive coupling mechanism, such as a belt and pulley mechanism, operably couples the drive motor to the drive shaft or shafts.
The present invention may include a method of using the carrier tape recycling apparatus to recycle bare carrier tape dispensed from a manufacturing system. In an exemplary embodiment, a carrier tape recycling apparatus according to the present invention is disposed proximate a manufacturing system dispensing bare carrier tape from one or more feed lines. The recycling apparatus is configured to support the desired number and size of tape reels. An end of the bare carrier tape being dispensed from each feed line is then secured to a hub of a tape reel. As bare carrier tape is dispensed from a feed line of the manufacturing system, the bare carrier tape is wound onto a tape reel as that tape reel is rotationally driven by the reel drive mechanism. If the manufacturing system halts the flow of carrier tape from a feed line, the slip drive provided by the reel drive mechanism allows a tape reel disposed in the recycling apparatus and receiving bare carrier tape from the halted feed line to cease rotation, or stall, while simultaneously allowing other tape reels disposed in the recycling apparatus to continue rotating and receiving bare carrier tape from the manufacturing system. When a tape reel is full of bare carrier tape, the full tape reel is removed from the recycling apparatus by simply lifting the full tape reel upwards out of the reel drive mechanism. An empty tape reel may then be inserted in place of the full tape reel.