Traditional feeder setup using tape-and-reel can drain time. There’s a quick and better way.

Tape-and-reel is the preferred method of feeding electronic components for automated SMT assembly because of ease of use and high repeatability. Everything from resistors to BGAs to odd-form components is packaged in tape-and-reel. But costs of feeder setup – some hidden – can drain profits through lost inventory and production time. Reel splicing kits can dramatically improve reel setup and changeover efficiencies to improve any PCB assembly operation’s bottom line.

SMT feeder tape is a two-piece system: The bottom tape is embossed with pockets to hold individual components, and the top tape seals the pockets to hold components in place (Figure 1). The bottom tape, known as carrier tape, has sprocket holes punched along its edge(s) for precise indexing of components to their pick positions. The top tape, or cover tape, is sealed over the pockets by either heat-activated adhesive (HAA) or pressure-sensitive adhesive (PSA).

To set up a reel of components on a pick-and-place feeder, the reel is loaded on a spindle, and the tape is threaded through a series of guides, tensioners and drive sprockets. The first 12" to 18" of cover tape are peeled back and wound onto a take-up spool. The components in the pockets under the peeled back cover tape cannot be machine-picked and are usually scrapped. High-value components may get manually placed or manually fed to the placement machine during the production run.

Loading a reel into a feeder and onto a machine takes an operator 1 to 4 min., depending on the reel configuration and placement system being used, and can de-tape between 15 and 150 components per reel, depending on their size.

Tape splicing kits eliminate production line downtime for replacing empty reels and component de-taping during reel setup. A splicing kit typically consists of a set of shims, a crimping tool and a variety of cover tapes (Figure 2). The shims interlock with the feeder tapes’ sprocket holes to join two ends of tape together, and the crimping tool secures them in place. Splicing shims and tools are universal; they work on all tape sizes from 8 to 56mm, and in all pick-and-place equipment platforms.

Cover tape sizes and styles are selected based on their application. Basic cover tape connectors are 2" lengths of PSA tape that join the cover tapes of the two reels being spliced together. They are installed after crimping the shim to the carrier tapes. Cover tape connectors may be used as singulated strips or may be combined into a one-piece unit with the shims for easy installation. Specialty one-piece units for certain smart feeders integrate an additional strip of cover tape to signal the start of a spliced reel to the machine.

Cover tape extenders (Figure 3) are longer pieces of tape that act as a leader for the take-up spool. They have adhesive only on the end that affixes to the reel’s cover tape, and are about 20" long. Extender tapes are available in one- or two-ply. Single layer extender tapes are most common; dual-layer tapes are used in situations where the original cover tape is difficult to peel. All cover tape connectors and extenders are compatible with both HAA and PSA reel cover tapes, and come in standard feeder tape widths of 8, 12, 16, 24, 32, 44 and 56mm.

Tape extenders. Cover tape extenders are extremely popular with high-mix PCB assemblers because they reduce component costs and ease kitting logistics. Frequently changing line setups can de-tape lots of components. To deal with this issue, PCB assemblers can 1) write off the inventory as setup scrap, bearing the full cost of the parts, 2) manually feed the components, stopping to load the machine for each placement and slowing overall production, or 3) hand place the components, if possible, increasing the probability of creating defects. There is a price to be paid for each option, and PCB assemblers are forced to choose. More
important than the cost, however, are the logistics of kitting the components, especially for EMS companies that perform low-volume consignment builds. Components are often kitted in exact multiples of the PCBs being built, without any allowance for setup or scrap. If the CEMs can’t hand feed or hand place the components, they must ask OEMs for extras.

Tape extenders can eliminate much of the cost and pain associated with frequent line changeovers. They can reduce scrap, maintain the productivity of automated assembly processes, and prevent logistical headaches. As lot sizes get smaller, the savings realized by using cover tape extenders get bigger.

Splicing in high-volume assembly. High-volume PCB assemblers that build larger lot sizes also save money with cover tape extenders, but achieve the greatest cost benefits by keeping production lines continuously up and running with reel splicing. High-volume manufacturing economics rely on high machine utilization rates; stopping machines to replace empty reels is an enormous drain on efficiency and profitability. While it only takes a few minutes for an operator to change a reel, those minutes add up to hours over the course of a shift, week or month. By splicing a fresh reel onto the end of a nearly empty reel before it runs out, the machines operate continuously with no stoppage.

High-volume manufacturers often employ portable splicing carts to travel around the factory floor (Figure 4). The carts are outfitted with all necessary splicing supplies, including scissors, shims, crimping tools, dispensers for the various cover tapes and storage areas for new and empty reels. They are small, rolling workbenches that boost the efficiency of the operators as they boost the efficiency of the assembly line.

Whether a PCB assembly operation is considered high mix/low volume or low mix/high volume, it can benefit from the use of tape splicing kits. Extender tapes eliminate the inventory scrap on feeder setups; reel splicing prevents machine downtime for parts replenishment. Shorter production runs realize greater benefits from tape extenders to minimize scrap rates, and longer production runs realize greater benefits from tape splicing to maximize asset utilization.

Rob Sierra is the owner and president of Sierra Electronics; rob@tapesplice.com. 

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