Carton control is the key

This California tea producer needed to run multiple flavors from four cartoners to one case packer simultaneously and quickly in limited space without damaging the product.

Family owned and operated, Yamamotoyama was founded in Tokyo in 1690. Since that time the company has expanded its operations around the globe while staying current with modern manufacturing methods. Today, the company remains family owned and continues to specialize in manufacturing green tea and nori seaweed.

Recently, Yamamotoyama of America was seeking to improve its Pomona, CA, production operations to achieve greater productivity and flexibility in producing multiple products. The facility operates multiple IMA tea bag manufacturing and cartoning machines, each of which can produce 300 tea bags (which is 18 full cartons of tea bags) per minute. Once cartons are produced, the next step in the process is packing the full tea cartons into shipper cases, then labeling the cases and palletizing them for shipment. As management at Yamamotoyama planned to expand production, they needed to add one more IMA automated case packer. A carton delivery conveyor system from four tea cartoners to the case packers was needed, with the ability to organize multiple flavors to the case packers in the proper groupings of 12 cartons of flavor A, 12 of flavor B, 12 of flavor C, and 12 of flavor D.

The solution the firm implemented was designed and integrated by TransAutomation Technologies. Essential from a hardware perspective is a network of VarioFlow flexible, modular, plastic chain conveyors from Bosch Rexroth. As a member of the Bosch Rexroth ProBuilder network, TransAutomation Technologies was plenty familiar with what the VarioFlow conveyors can bring to the table. Daniel Goldstein, COO of Yamamotoyama of America, was confident in the solution that TransAutomation was proposing. “We needed the system to be locally supported, and we were confident in the fact that the system would be built and completely integrated by the local ProBuilder,” says Goldstein.

VarioFlow plus is a flexible, modular plastic chain conveyor system used for moving high volume packaged goods and other consumer goods, such as packaged foods, pharmaceuticals, and healthcare products. It can be used to move products horizontally, vertically, on incline or decline, overhead, sub-floor, around obstacles, and over long distances. Workpiece pallets can be used to convey products in applications where positioning or higher precision is needed. VarioFlow plus is simply the quietest, most flexible, energy-efficient and easiest to assemble plastic chain conveyor available. The management at Yamamotoyama were interested in VarioFlow plus because of its smooth-running belt, low-profile channel, tight radius curve wheel, and ability to create a “stacked” conveyor configuration with vertical curves, which is why they contacted Bosch Rexroth.

Each IMA machine can produce just one flavor of tea at any given time. However, the Yamamotoyama plant is arranged such that the machines are located in groups, each producing 18 cartons/min. This meant that the conveyor system had to accommodate this volume of tea cartons per minute, and accurately merge/induct groups of 12 cartons into the case packer, without error. A second requirement was to protect the carton surface. The tea product is packaged in glossy, shelf-ready cartons, and the appearance of the carton needed to remain neat and unscratched. Therefore, a smooth surface conveyor belt would be required. The third challenge was one of space. The plant equipment spacing is very compact, with minimal lateral distance between production equipment, so the conveyor system needed a very small footprint.

Controls package
While the VarioFlow conveyors perform the physical conveyance of cartons from cartoners to case packer, the conveyors had to be complemented by custom mechanical devices for controlling product groups of cartons. It also had to be integrated with an electronic controls system that would count cartons queued up on four VarioFlow conveyors and, via a priority counting system, would release cartons onto a single trunk line leading to the case packer. For these controls tasks, TransAutomation selected a C-more HMI from AutomationDirect. C-more is easily programmed with easy-to-use configuration software that provides a powerful set of tools for developing simple or very complex applications. The C-more software makes touchscreen panel setup and C-more programming quick and simple, and all C-more touch panels use the same programming package.

According to Phillip Meilbeck, President of TransAutomation Technologies, the C-more HMI/PLC combination was selected based on functionality, availability, and ease of programming. Feeding carton position information to the C-more controller, he adds, are a series of Rockwell photoeyes. “Accurate control of 12 cartons at a time was critical,” says Meilbeck.

The Yamamotoyama system receives the output of the IMA cartoners onto individual take-away conveyor runs. The Bosch Rexroth conveyor elevations were varied through the use of vertical inclines and lateral off-sets to achieve a stacked configuration, allowing for a very narrow footprint. At the terminus of the system, the product travels in a vertical incline onto the trunk conveyor through the use of Bosch Rexroth vertical curve declines.

Once cartons approach the end of the Bosch Rexroth conveyors prior to the case packer, they stop and accumulate at the end of each of the conveyors. An electronic controls system counts the cartons in queue, and via a priority counting system, the control PLC establishes which conveyor lane is to be released onto the trunk line. Once 12 cartons are accumulated on any given conveyor, that conveyor is “eligible” to release the slug of 12 cartons onto the trunk line. The slug release is accomplished through the use of pneumatic stops, escapements, and right-angle pushers. The shortest conveyor line with the least amount of accumulation capacity has the highest priority, then the second, and so on. As a conveyor is signaled to release product, a custom right angle pusher activates and ejects the cartons six at a time onto the Bosch Rexroth trunk line. Two pusher activations (2 x 6) are required to create a slug of 12 cartons, as required for the case packer. All conveyor sections in the accumulation area are constantly monitored by the electronic controls system to keep the cycle repeating throughout the production run. Once tea cartons enter the IMA case packer in groups of 12, two full shipper cases of six cartons each are produced and discharged from the case packer. Cases are printed and then rotated upright, to be palletized by the robotic palletizer.

The solution has been a huge success for the manufacturing facility, increasing the speed of production without damage to the products, all in a small footprint. Mr. Goldstein states that “the project went very well from start to completion.

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