Robotics Case Studies
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Product Handling Put to the Test at Twizzlers Candy Plant
Yaskawa America, Inc. Posted 02/07/2011Twizzlers® candy from Y&S Candies, Inc., a division of The Hershey Company, is an American candy favorite, known for its sticky, pliable consistency and sweet fruity flavors. However, some of the qualities that make it such a satisfying treat also make it a product packaging challenge.
Y&S produces and packs all conventional Twizzlers® candy varieties in a 290,000-sq-ft plant in Lancaster, PA. Since 2000, it has added automation capabilities to most of its nine packaging lines, replacing manual operations as product demand has dictated. Most recently, the company automated two of its packaging lines with MPK 50 robots from Motoman that transfer the candy products from processing to packaging, without losing a single soft, sticky strand.
Twizzlers® Twists are made through a process where the candy is extruded onto a flat board and then dried. In the past, up to eight operators were needed on each line to remove the boards from the drying racks, pull the strands of candy from the boards, and then place groups of candy into the infeed of a flow wrapper for packaging. “Before automation, those manual jobs were basically our highest-risk operations,” says Jake Wildes, packaging systems engineer for Y&S. “Those positions required a lot of repetitive motion.”
Y&S’s directive for Motoman was to find a solution capable of taking candy from a discharge belt and placing it directly onto film feeding a Hayssen flow wrapper. Y&S required that the candy be placed precisely in position on the film, which is fed into the machine on a 16-ft infeed, at a rate of 30 boards/min.
In Wildes’ opinion, the biggest challenge for the Motoman system would be to place the candy where it belonged on the film the first time. “When Twizzlers® Twists are made, they are kind of like ropes. They are flimsy, and at times they can be sticky or oily. So they tend to stick to one another when you pack them into a bag,” he says. “The hardest part is transferring that group of candy onto the wrapper film without losing strands over a transfer or having them hang up. Or when they get dropped on the film, they might fall out of order.
“We were trying to get away from any kind of traditional infeed—like a bucket infeed or a metering system. The Motoman system sets the candy directly onto the film, which eliminates all transfer points, eliminates pieces getting lost in the transfer, and eliminates the transfer that causes groups to become misaligned.”
In conjunction with the Motoman robots, Y&S added what it calls a Skiver system to the lines that automatically removes candy from the board. Used for some time on another Twizzler line, the Hershey-engineered Skiver takes the Twizzlers from the board and groups them on a discharge belt in the same orientation they held on the board.
To precisely pick the candy from the discharge belt, Motoman’s MPK 50 four-axis, 50 kg-payload robots use an aluminum boom that measures approximately 55 in. and is fitted with a series of five, six, or seven grippers, depending on the Twizzler® candy variety being run. Delrin thermoplastic grippers pick the required amount of candy from the belt, move to the wrapper infeed, track the film at speed, and release the product onto the film when triggered by a photoeye at the infeed. The robots are equipped with the Motoman DX100 controller.
In the six months since the new robots were installed, Wildes says Y&S has seen greater efficiency and productivity, as well as less film waste, and “labor savings are huge.” He notes that both lines are running at speeds well above those achieved when the lines used manual operations, with one of them at times running 150% of the previous standard. “We also have less rework and waste, and less product being lost at transfer points,” he adds.
By Anne Marie Mohan, Senior Editor, Packaging World Magazine, reprinted by permission.