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Robotic palletizing suits soy milk just fine

Lauren R. Hartman

January 29, 2014

13 Min Read
Robotic palletizing suits soy milk just fine

Soy milk and organic products manufacturer SunOpta, Inc. has become synonymous with soy. A strong, vertically integrated player in the natural, organic, kosher and specialty food and ingredient industries, SunOpta, through a combination of internal growth and acquisitions, is committed to its products. Based in Norval, ON, about 45 minutes northwest of Toronto, the company has a food operation comprising specific groups devoted to grains and soy products, fruit, ingredients, packaged products and distributed products. In January 2005, SunOpta Aseptic, the company's aseptic packaging facility in Alexandria, MN, a few hours northwest of Minneapolis, opened a new 45,000-sq-ft addition of office and warehouse space that consolidates warehousing previously located in five regional facilities. The Alexandria plant aseptically copacks soy milk for various customers and its own label in 1-L "Slimliter" and 1/2-gal paper/film rectangular carton sizes at a rate of 500 and 625 cases/hr, respectively. The finished, shelf-stable packs are loaded into wraparound, corrugated shipping cases in three different configurations. The cases hold six or 12 Slimliter packs each or eight 1/2-gal packs each.

SunOpta Aseptic is accountable for packaging about 130 stockkeeping units of soy milk products in several varieties and flavors that are distributed across the U.S. under at least 11 brand names. The company is also drinking in more business, so has been in need of more plant space and more automated packaging equipment. Running three eight-hour shifts, six days a week until this month, the company is increasing production to three eight-hour shifts, seven days a week, in order to better meet the needs of its customers and the demand for its products, says plant manager Paul Empanger. "We've grown so much in such a short period of time that our capacity has increased nearly fourfold in the past few years," he says.

We were able to see our palletizing equipment being built...This made it easy to work with their engineers and programmers.

As part of the expansion and to further solidify its position as a key innovator in soy products and other foods, the company decided to upgrade its palletizing operation with fully automated robotic equipment, which has improved efficiencies and has helped support its growth. After evaluating three or four different equipment vendors, SunOpta Aseptic found a solution in the form of a robotic system custom-built by Brenton Engineering (www.brentonengineering.com) that adds flexibility, helps prevent injuries, provides tight, secure and neat caseloads and keeps labor to a minimum. Today, only one operator is needed to oversee the new palletizing process, which replaces a manual operation.

"The system has eliminated a labor-intensive operation," Empanger tells PD during a visit to the plant. "We used to need about nine people, three per shift, to palletize, so we utilized a temporary labor force, but scheduling that can be difficult, especially as our volumes continued to grow. We knew we'd have to automate the process in order to keep up."

The robotic palletizing station Brenton designed incorporates a Fanuc (www.fanucrobotics.com) M-410iB160 industrial palletizing robot, outfitted with four Lock 'n Pop (www.locknpop.com) adhesive applicators that secure the cases with a water-based adhesive. At the end of the palletizing sequence, the loads are secured further by an Orion (www.orionpackaging.com) FA-44 conveyorized turntable stretch wrapper.

Says Neil Hammer, director of customer accounts and service, "We looked at several options for palletizing, but always kept going back to Brenton for their reliable equipment. We visited a dairy nearby to see how their systems worked and were impressed. Brenton's also conveniently located nearby, and we were able to see our own palletizing equipment being built in their plant. This made it easier to work firsthand with their engineers and programmers."

With a compact design that makes it suitable for a limited amount of floorspace, the system uses a multizone, vacuum-picking, end-of-arm tool (EOAT) with 11 vacuum-gripping zones and 62 suction cups. The four-axis robot also features a modular construction, an electric servo drive and Fanuc's System R-J3iB programmable machine controller. An integral Fanuc iPendante portable operator interface teach pendant control maximizes performance and makes it easy for operators to use the system.

In addition to the integral robot interface functions, the intuitive teach pendant provides help and diagnostic functions as well as enhanced robot and process data, allowing SunOpta operators instant access to critical information. It also serves as a human machine interface (HMI) for conveyor jog functions. The robotic palletizer can build virtually any pallet pattern, and can handle palletizing setup and sequences, basesheet insertion and various case weights, picking speeds and picking and placing patterns. The standard robot memory configuration stores 50 to 100 unit-load configurations in memory and with file management, addresses up to 999 unit loads.

We had a limited amount of space to work with, but the new system fits in well.

If a standard, built-in pallet pattern doesn't meet certain application requirements, the Fanuc PalletTool PC software automatically calculates a number of optimal patterns. With a usable payload capacity of 160 kg (about 352 lb) and 0.5-mm repeatability, the robotic palletizer can simultaneously pick and place the shipping cases on three separate pallets within the workstation, simultaneously remembering each of their pack patterns. This is accomplished, says Brenton's Jim Horton, by unit-load data resident in the robot's memory. SunOpta's line operators can modify the patterns using the teach pendant or they can then create their own new patterns using the PalletTool software.

Brenton provided the robotic workstation with assorted conveyors, automatic pallet and basesheet dispensers that are controlled by the Fanuc PMC and a ladder-logic system resident in the robot controller.

The system has 360 deg of base rotation and a 10-ft reach and picks cases from a 5-ft-high pick-and-place platform, all within a tight 50X50-ft space. Able to handle the output of three of SunOpta's production lines (a fourth can be put into service as needed), the system was installed in January 2005, just after a Slimliter cartoning line was added. The new palletizing station has freed up floorspace and provides more access to and from product processing and from the upstream packaging area. Enclosed in a safety cage, the robotic system cell resides at one end of SunOpta's warehouse floor, flanked on the outside by an empty-pallet magazine that can be replenished without interrupting the palletizing operation and by stacked caseloads on the other side, which keeps system uptime on schedule. SunOpta uses the basesheets to protect the bottom layer of cases on each pallet. A magazine holding the corrugated basesheets next to the empty-pallet dispenser inside the cell holds about 250 sheets, which requires replenishment by an operator approximately every four hours, with little effect on production time.

In production, the soy milk products are aseptically packaged in the Tetra Brik(R) cartons from Tetra Pak (www.tetrapak.com) in an adjacent but separate filling room on a set of Tetra Pak hermetic form/fill/seal systems. A set of three TBA/8 machines produce, peroxide-sterilize, fill and hermetically seal the Slimliter packs while one A3/Flex aseptic system does the same for the shelf-stable product in the 1/2-gal Tetra Brik container. Next, regardless of package configuration, the soy milk packs travel through an accumulation conveyor and then through an opening in the wall to the capping/case-packing room, where Tetra Pak's ReCap(TM)3 applicators first outfit each package with a hinged flip-cap applied over the packs' laminated membrane openings. The flip-cap's specially designed grooves guide the soy milk during pouring, allowing good control of the outflow with little product residue.

The cartons of soy milk are then case-packed on Tetra Pak's Tetra 70 casing equipment, which generates about 25 cases/min. SunOpta uses wraparound cases in various weights and configurations, depending on customer requests. The cases, most of which are supplied by Menasha (www.menasha.com), are filled with the primary soy milk drink packs, and are ink-jet-coded on two sides with product, brand details and production information by a Zanasi (www.zanasi.it) unit. The cases are also marked with a colored dot by a Zanasi roller coder to segregate them to the proper pallet load on which they will later be placed, and they're labeled with a corner wrap "identification" label on a labeler from Paragon Labeling Systems (www.paragonlabeling.com) before they convey on three production lines out of the room with the narrow side leading. Then, they merge onto two overhead conveyors.

Read about how PHARMAVITE upgraded its tablet and capsule cartoning operation with a new blister-packing line that's outfitted with a robotic palletizer: www.packagingdigest.com/ info/pharmavite

Brenton also furnished an electric eye and a bar-code reader that spot the color dot and code on each case, confirming each case's specifics and production-line source and direct the cases to the proper accumulation/infeed conveyor leading to the palletizing unit. Cases filled with the 1/2-gal packs of soy milk are directed to travel on one conveyor, and cases holding either the six- or 12-packs of Slimliter packs move onto the other. An optional fourth conveyor line can be set up as needed to transport cases of the 6- and 12-pack Slimliters to the robot.

As the cases enter the palletizing area, they descend on an Ermanco (www.tgw-ermanco.com) roller conveyor into two conveyors to the palletizing cell. At this point, the two conveyor lanes make a 90-deg turn to the picking area. Empanger says SunOpta Aseptic packs 150 cases of six-pack Slimliters per pallet, 30 per layer, five layers high, or 75 of the 12-pack cases per pallet, 15 per layer, five layers high or 56 cases of 1/2-gal cartons per pallet, 14 cases per layer, four layers high.

Just prior to reaching the picking section of the workstation, an infeed conveyor accumulates cases in front of the robot and forms a partial row of cases (the EOAT can grasp up to seven cases at a time, depending on their size and weight) before it cross-pushes the row into picking position. When handling the eight-count cases of 1/2-gal soy packs, three of the cases convey into the accumulation area and are cross-pushed onto the picking table, followed by three more cases. The last three are then cross-pushed on to form a group of six cases to be picked. This process is repeated to form the optimum layers of cases. As rows of cases form, the conveyor aligns them before the picking process begins. Bump turners are found on all of the accumulation conveyors and activate according to what pallet pattern is desired. Meanwhile, the empty-pallet and basesheet dispensers activate and the pallet dispenser supplies an empty, wooden, 40x48-in. pallet (from several sources) and a corrugated basesheet (from Menasha) to the pallet-loading positions on-demand.

As the empty-pallet conveyor system transfers a pallet to the robotic workstation, the pallet stops in front of the basesheet dispenser, after clearing a sensor on the system. The dispenser then places a basesheet on the pallet, and the two sequence forward to the last position on the empty-pallet trunk line. The empty-pallet conveyor, in turn, feeds the pallets into the workcell to one of the three robotic picking locations. The cases accumulate and are turned and properly oriented by grippers as they move into place in the three respective picking sections. This sequence repeats until all three stations on the pallet trunkline are filled.

With a whir of motion, the robot's EOAT starts its sequence and moves to the first pick station to form a partial layer of cases on the proper pallet. After it places a layer on the pallet at the dedicated pallet station, the arm then retreats back to its original position and, once a layer is ready, the EOAT's adhesive nozzles spray the Lock 'n Pop adhesive to the tops of the cases. The robot then begins placing another layer of cases on the pallet and counts its way down. The robot then moves to the next pick station that is complete and places another partial layer of cases on the correct pallet. The process is repeated until the pallet load is full and ready to be wrapped. Next, the load conveys out of the robotic cell and moves a jog or two downstream onto a trolley conveyor adjacent to the stretch wrapper. This shuttle conveyor merges two of three pallet-discharge conveyors together into the stretch-wrapper infeed. Then, the robot and stretch wrapper send each other "handshake" signals to sequence the pallet into the wrapper, and the load is stretch-wrapped in clear film by the dual-adjustable-carriage wrapping system. When the load is completely wrapped, it receives a "license plate" label printed with product identification, a bar code, a date of manufacture, an expiration date and production information. Finally, the load is forklifted and moved to the 35,000-sq-ft, 20-row warehouse, where it can be neatly stacked up to five loads high and five loads deep.

If the palletizer goes down for any reason, it won't affect production on the packaging lines, Hammer says. "The cases simply wait on the accumulation conveyor."

Empanger points out that productivity is reaching 100 percent on the three cartoning lines. "We'll see a return on our palletizing equipment investment within three years' time," he tells PD. "We're impressed. We'd like to add another system like this one soon. It's a well-designed system." He says SunOpta Aseptic may soon add another robotic palletizing station if demand calls for adding another packaging line upstream. Brenton developed the workstation in about 20 weeks. Says Hammer, "We had a limited amount of space to work with, but the new system fits in well. The Brenton crew really knows its stuff. The system is quite reliable and can handle more than three million pounds of product in a week. Labor costs in palletizing have dropped dramatically and we enjoy more consistently wrapped loads."

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