Panasonic Primary Battery Corp. of America's giant facility in Columbus, GA, is the only plant in the U.S. producing the company's AAA, AA, C, D and 9-volt retail alkaline batteries. The company had been packing the batteries in single-face corrugated cases for shipment to customers. In 2004, the marketing department decided that they wanted to add a new Panasonic product in which batteries were placed in trays that could be put directly on store shelves. The Columbus plant was tasked with coming up with a system that could do this both accurately and efficiently. “After considering the alternatives, we decided that an automated system that transported blister-packs of batteries through the packaging process in plastic, thermoformed inserts and incorporated a robot to do the final packaging presented the optimum arrangement,” says engineering manager Larry Brooks. “We had seen some very impressive, custom-designed equipment from Langen Packaging, Inc. (www.langeninc.com) in Europe, so we contacted them to discuss the project. There were a few times when they shook their heads at some of our ideas, but they never really resisted anything, and they were great to work with. They built some mockups of the equipment about a year ago, and we installed the finished line this spring.
A key element of the LRC-700 system is a robot from Fanuc Robotics of America, Inc. (www.fanucrobotics.com) that performs a dual function. On one hand, it loads battery blister-packs into the corrugated display trays, and on the other hand, it palletizes the shippers into which the trays are packed. “This dual operation was essential to the economics of the robot,” says Brooks. “We had originally thought of the robot as only packing the blister-packs into the display trays, but that would have only utilized part of its time. By having it also palletize the shippers, we utilize more than seventy-five percent of its time, and that helped justify its cost. Langen was a little concerned about the dual-purpose robot, but they came through like a champion. Their programmer, a gentleman named Wen Chen, did a marvelous job.”
The LRC-700 system is designed to run 15 different styles of battery blister-packs: five AAA styles, six AA, two 9V and one each of C and D batteries. The blister-packs are produced on another automated piece of equipment, which is attached to the LRC-700 by a conveyor system. To start the packaging operation, the blisters are conveyed beneath two parallel, vertical starwheels, one on each lane, which space the packs for processing. The blisters reach the starwheels randomly, and a sensor tells the wheel that a blister is present. The servo-driven wheel then indexes to release the blister into a flight of the downstream conveyor. The starwheels seem simple, but, in fact, their design is critical to the operation.
“The vanes on the starwheels must have the proper shape and angle to exactly match the blisters, so they don't damage or squeeze the blisters,” says Brooks. “Different settings are required for each blister-pack, and the spacing of the vanes around the wheel must also be adjusted to match each blister.”
The blister-packs are loaded into plastic-tray inserts that are transported through the machine in pucks on two parallel conveyors. Each Panasonic blister-pack configuration of batteries has its own plastic-tray insert, but they all fit into the same pucks, thus eliminating the need to change the pucks. The conveyors are designed in a continuous racetrack pattern. The pucks are loaded with the blister-packs, transported to the robotic packager and then come back around to pick up the next load of blister-packs.
The blisters leaving the starwheels are inspected by a vision system from DVT Corp. (www.dvtsensors.com) that verifies the polarity orientation in the package, as well as checks for missing batteries. Before the puck enters the blister-loading station, it stops beneath a feeder that sets a clear plastic tray into the insert. The tray contains grooves into which the bottom flanges of the blister-packs are loaded. During Packaging Digest's visit, the line was assembling groups of 12 blister-packs containing four AA batteries each, so the inserts had 12 grooves. Different battery configurations and sizes require different plastic-tray inserts.
The puck then enters the loading zone, where the conveyor travels down an incline. At this point, the puck is slowed down, and the individual blisters drop into the grooves in the plastic-tray insert. After the proper number of blister-packs are loaded into the insert, the puck is released and travels around a U-bend on one of the parallel conveyors to the robotic tray-loading area. E-series servo drives with FM-3 control modules from Emerson Control Techniques (www.emersonct.com) are incorporated into the starwheels and the puck-handling system.
A reciprocating model GF42 tray erector/feeder from Specialized Packaging Machinery, LLC (www.spgroup-inc.com) withdraws individual display-tray blanks from a magazine and erects them. Side belts discharge the trays into a lugged conveyor, and a servo-driven main drive indexes them to the robotic loading station. The LRC-700 actually loads two display cases—one behind the other—on each conveyor simultaneously. During PD's visit, the plant was running cartons containing two sets of battery packs side-by-side, so at this point, the robot descends and picks up four sets of blister-packs—two sets from each conveyor—and places them side-by-side into the trays. The end effector that picks up the blister-packs consists of parallel plates that close on the two sides of the battery packs, including the plastic trays. After gripping the battery packs, the robot rises, swings over the display trays and descends to deposit the battery packs through oscillating funnels into the display trays.
The LRC-700 system also runs display trays containing only one row of battery packs. In this case, the battery packs are delivered to the robot on one conveyor, and the robot picks up two sets (for the two trays) at a time rather than four, and place them into the trays. After the blister-packs have been removed, the pucks travel back around the racetrack and repeat the loading process.
The display trays leaving the packer travel over a checkweigher from Alpha Checkweighers (www.alphacheckweighers.com), which is part of All-Fill, Inc. (www.all-fill.com). The electronic control system for the checkweigher includes an alphanumeric LCD display plus an individual LED weight display, up to 25 programmable product setups, sample and hold display functions, automatic setup of static and dynamic calibration, startup and dynamic self-diagnosis with error messages, auto zero to compensate for product spillage and digital automatic feedback control to the filler. The standard statistical data package for the checkweigher includes counters for each weight zone and total count, average and standard deviation on the last group of 50 packages.
Out-of-spec trays are rejected as they leave the checkweigher. Acceptable trays are conveyed to a manual packing area, where they are packed into corrugated shippers, which are taped shut by a Little David top taper from Loveshaw, an ITW Company, Little David Products Div. (www.loveshaw.com). A labeler from Labeling Systems, Inc. (www.labelingsystems.com) applies labels to the shippers, after which they are conveyed back to the robot, which has a second system consisting of vacuum cups on the same end-effector as the tray-loading system. Between loadings of battery packs into the display trays, the robot picks up the shipping cases and automatically palletizes them. Sensors on the battery-pack and shipping-case conveyors detect when product is present and initiate the two robotic cycles.
“Installation and startup went very well,” says Brooks. “Langen had a startup crew here for a week, and then two of their technical people came down to help us start the system, which took another week. The system currently is a key piece of equipment in filling our Panasonic orders and maintains a high level of run time and efficiency.”
|More information is available:|
|Langen Packaging, Inc., 905/670-7200. www.langeninc.com.|
|Alpha Checkweighers, 610/524.7350. www.alphacheckweighers.com.|
|All-Fill, Inc., 610/524-7350. www.all-fill.com.|
|DVT Corp., 770/814-7920, www.dvtsensors.com.|
|Emerson Control Techniques, 952/995-8000. www.emersonct.com.|
|Fanuc Robotics of America, Inc., 248/377-7000. www.fanucrobotics.com.|
|Labeling Systems, Inc., 201/405-0767. www.labelingsystems.com|
|Loveshaw, an ITW Company, Little David Products Div., 570/937-4921. www.loveshaw.com.|
|Specialized Packaging Machinery, LLC, 770-482-4808. www.spgroup-inc.com.|