Packing and palettizing of pretzel products for dispatch to stores and outlets.
Build a packing system that could accommodate various size packages and could work with both the stand up and lay flat pouch case configurations.
Two parallel case packing lines, one with three ABB IRB 360 FlexPicker® delta robots and one with two, as well as an ABB IRB 660 to load pallets with packed cases.
ABB robots are helping a US based pretzel manufacturer to pick and pack a wide variety of product packages into cases and then stack the cases on pallets. The robot solutions have enabled the plant to steadily increase the amount of product it processes, achieving double the productivity of any other plant in the company.
Founded in 2012, Dot’s Homestyle Pretzels is the third largest pretzel brand by sales in the United States. Already operating plants in North Dakota, Arizona, and Kansas, the company opened a fourth facility, also in Kansas, to meet increasing demand for its products. The 17,280 square metre plant features automated product preparation, handling, and packaging from beginning to end, and, like other Dot’s plants, it operates a 24/7 production schedule.
The challenge was to handle the varied packing sizes. Dot’s twisted pretzel sticks come in three flavours with a choice of eight package sizes ranging from 0.5 to 32 ounces. The most popular retail 16 ounce size is available in both standard and point-of-purchase display cases.
To achieve the flexibility required, Dot’s turned to Viking Masek Robotics & Automation (VMRA).
“The biggest challenge for VMRA in designing the case packing systems was to accommodate the various sized packages and facilitate both the stand up and lay flat pouch case configurations,” said Kent Schmidtberger, Dot’s project manager at the Edgerton location. “They basically had to accomplish, through robotic automation, the packing of all the packages that we manually process at our other facilities.”
Flexible packing lines use ABB robots
VMRA designed two parallel case packing lines, one with three ABB IRB 360 FlexPicker® delta robots for the 0.5, 1.0, 1.5, and 2.5 ounce bags, and one with two IRB 360 FlexPickers for the 5.0, 16.0, 24.0 and 32.0 ounce bags.
The 6 kg payload delta robots pick the packages off a conveyor and place them in the various case configurations using different vacuum-based end effectors.
The three smaller size bags are vertical form filled pillow bags with heat seals on each end. The case packing line with three robots is optimized for maximum throughput, with automatic changeover functions to accommodate the differing pick-and-place requirements for each size. The smaller bags are typically destined for convenience stores, vending machine and airline hospitality commissaries.
Changing from one bag size to another takes only a few minutes and is handled by a few button presses at the machine HMI. Once the new recipe is accepted, the machine automatically adjusts the physical and program parameters to handle the next bag size.
The 16 oz. bags are picked up by the robots and laid flat into a dumper bin next to the case. When the bin is filled with the appropriate case quantity, it automatically tilts and dumps the bags into the case in an upright orientation. This positions the bags for correct display in the shop. Products intended for distribution centers or locations where product is stocked on shelves are packed flat directly into non-display cases. This extra automation provides the flexibility to pack multiple 16 oz. case configurations on the same line.
The large bag line also incorporates a tool changer that switches between two different end effectors to match the product size being packed. VMRA worked with Dot’s production team to optimize the vacuum tools for the project. The geometry of the tool, the suction cup design, and robot programming were all engineered for maximum performance and lifespan.
One palletizing robot serves both lines
The case packing lines feed a single ABB IRB 660 palletizing robot. With a 3.15 meter reach, the robot can reach cases from the end of both conveyors, alternately picking cases from each conveyor to simultaneously build a separate pallet for each product package size.
The palletizing robot uses a vacuum-based foam area gripper designed by VMRA to meet the needs of the application. With a single tool, the palletizing robot can accommodate single and multi-product picks to maintain optimal throughput. Completed pallets are transferred to a main exit conveyor, before being stretch wrapped and sent to the warehouse to be staged for shipping.
System designed using ABB RobotStudio
VMRA used RobotStudio®, ABB’s offline simulation and programming software, to help design the robotic lines.
Using two application specific add-ins to RobotStudio, ABB’s PickMaster® for the case packing lines and the Palletizing PowerPac for the palletizing system, VMRA experimented with highly realistic simulations of different automated configurations to achieve the optimal design for each line.
As well as helping identify the relative positioning of each robot based on their footprint, reach and payload, the RobotStudio software can select and position all other line components, such as conveyors and other fixtures needed to perform the various line processes. RobotStudio can also identify any potential bottlenecks and calculate accurate space requirements and cycle times.
“RobotStudio is a great program that allows us to simulate real world system configuration scenarios offline, which saves a lot of time throughout the system design and commissioning processes,” said Dave Raschke, the VMRA project manager for the Dot’s project. “In essence, we were able to experiment with complete and accurate system design variations through risk-free trial and error until the optimum system was designed.”
Results have been very good, with the Edgerton facility processing more pretzels each successive quarter it has been in operation, increasing its productivity to nearly double that of any other Dot’s plant.
“Our prosperity over the last few years allowed us to gather the resources needed to pursue automation, which we believe to be the natural progression in keeping the company on an aggressive growth trajectory,” said Kent Schmidtberger. “I came from plants that were heavily automated, so I know the benefits. Not only are we able to produce more pretzels, but we do so with greater consistency. Plus, we now have the added flexibility to further expand our product lines in the future.”