White Castle's Robotic Path to Packaging Automation
Integrators used software to identify the optimal positioning of robots on the line based on their footprint, reach, and payload. The software also validates the requisite system performance in relation to the existing components of the packaging line.
The latest automation installation at the plant is a two-ABB IRB 1200 robot station that case packs the retail cartons into 12-ct shipper cases.
Generally regarded as the world’s first fast-food hamburger chain, White Castle, founded in 1921, has over 350 locations in 15 states, mostly in the Midwest and metro-New York City. On the surface, that leaves a good portion of the U.S. without access to the indulgent palate pleasure of iconic square sliders, loaded with grilled onions and perhaps a slice of cheese.
That was the case until 1987, when White Castle opened a retail division, which supplies merchants large and small across the U.S. with frozen, packaged sliders made at three U.S. factories. The factories mimic the way the sliders are made in restaurants but leave the final microwave preparation to the consumer.
The retail sales model has been quite a success. At the end of 2021 White Castle sold its six-billionth retail slider, with over 20% of that total having come in the previous three years.
Demand has been so high that White Castle’s Louisville, Ky. factory—one of the first White Castle frozen food plants opened in 1997—now operates three shifts, six days a week. It also serves approximately half of the U.S. retail volume, processing tens of thousands of pounds of meat in making 800,000 sliders per day.
Pre-cooked hamburger meat comes into the facility in log form and is sliced into individual patties. The patties are manually placed on bun bottoms, and then topped with grilled onions, (plus cheese during the shifts cheeseburgers are made), and the upper bun. The burgers are then flow wrapped two-to-a-package on equipment from Campbell Wrapper Corporation, and transferred into a blast freezer operating at 35°F below zero.
The Frigoscandia flash freezer has self-stacking belts with exits at the top. After an hour in the freezer the slider two-packs are gravity fed through a small chute onto a conveyor that leads to the three separate packaging lines; two parallel lines for 12-ct cartons sold at general retail locations, and one separate line for 16-ct cartons sold at wholesale clubs. Cartoning is done on Bradman Lake right-angle carton closers.
Recently upgraded articulated-arm robots
It’s notable that White Castle was an early adopter of robotics; the company is perfectly comfortable with robotic integration. Plant Manager Tony McGraw, now a 35-plus year veteran at White Castle, had nudged his company into ABB delta-picking technology as early as 1998 (see sidebar below for more about packaging robots’ early days). But a side effect of being an early adopter is that newer equipment is bound to arrive, and it’s wise to turn to the experts to know what’s coming down the pike.
That’s why as McGraw and his team began to explore replacement options and design configurations for the carton packing and palletizing area, they called in CIM Systems Inc., an authorized ABB robotic systems integrator located in Noblesville, Ind. The initial task was to address the new palletizing system, which presented some design challenges.
The first was a tight palletizing area, which required some out-of-the-box thinking to fit two full lines. The result was to position the end of the conveyor from each line perpendicular to the front of the robot, one just beyond the other, with a pallet station along the right side of the robot.
To further expedite production, White Castle also wanted the robot to pick empty 45-lb pallets off a stack and place them in the build station once a previous pallet had been built and moved to the stretch wrap station. This required a more complex EOAT design and intricate robot motion.
Simulation software optimizes system design
CIM used RobotStudio, ABB’s offline programming software, to experiment with highly realistic simulations of the palletizing cell while designing the EOAT and determining the optimal robot position and motion. As a system simulation is developed, RobotStudio can identify any potential bottlenecks as well as calculate accurate space requirements and cycle time metrics that the system concept would deliver if installed on the plant floor.
“With the two pallets being built next to each other we had to carefully coordinate the robot motion and pallet pattern, making sure the load would clear the first pallet, no matter its height, to safely reach the second pallet,” says Dave Fox, CIM President. “We also had to factor in the programming nuances required to adeptly pick and place the fresh pallets, and the clearances needed for the EOAT, which was bigger than most because of the need to pick up both cases and pallets. RobotStudio played a major role in designing and proving the performance of the system while accommodating all those variables.”
The palletizing robot used in this system is an ABB, four-axis IRB 660 palletizing robot with a 3.15-m reach and a 180-kg payload. This configuration provides enough length and strength to reach and clear all points in the palletizing cell from a stationary position, both horizontally and vertically.
The EOAT CIM designed and fabricated features vacuum cups that pick three 8-lb cases at a time for the palletizing operation, along with four pneumatically operated hooks positioned on each corner to securely handle each empty pallet. This combination enables the robot to execute both functions without requiring a tool change.
Case packing – the newest robots
The latest automation installation at the plant is a two-ABB IRB 1200 robot station that case packs the retail cartons into 12-ct shipper cases, a function that occurs along the packaging line after the upstream delta-style FlexPickers (sidebar below) and before the palletizing robots. Mounted on a common pedestal between the two packaging lines, the two lower-payload robots utilize vacuum EOATs to pick two retail cartons at a time and place them into the cases.
The new 5-kg case packing ABB robots, one dedicated to each line, replace a single, larger robot that served both lines with dwindling efficiency as production volumes increased. Manual operators, who were previously required to assist the process, have been moved to more rewarding jobs in the facility.
CIM again used RobotStudio to identify the optimal positioning of the robots based on their footprint, reach and payload, and to validate the requisite system performance in relation to the existing components of the packaging line.
Today, with the latest in robotic assistance, the line speed on each of the two 12-count lines is 15,600 burgers/hour per line. The 16-count line runs at 18,500 burgers/hour.
“The tremendous experience we have had with the ABB FlexPickers over the years caused us to look closely at ABB when it was time the replace our other robots. We were introduced to CIM Systems and we couldn’t be happier. The palletizing robot and the case packing robots have really increased the efficiency of our operation. They are truly plug and play systems that require minimal manual support,” shares McGraw. “One of our core values is something we call ‘Continuous Crave,’ which means we never stop working to get a little bit better each day. This investment is a perfect illustration of doing just that.” PW
Pre-Y2K Adopter of Delta-Style Robots
During the first several years of operation at White Castle’s retail facility, most of the packaging processes were handled manually. As the frozen sliders gained popularity and production volumes increased, Plant Manager Tony McGraw and his staff noticed certain areas of the packaging line that were causing backups.
One in particular was the packing of slider two-packs into the retail cartons, a highly repetitive task that involved the handling of frozen product. In effort to speed up this process and move employees into less physically stressful jobs, McGraw began to investigate a range of potential automation enhancements to the line. If a viable solution did exist, it had to be fast and accurate, and work in the existing space, which was very tight. The option that showed the most promise was a delta-style robot, a new technology that had been in development since the mid-1980s but had only recently been commercially available.
The key design feature of a delta robot is three arms, connected to universal joints at the base, which move in a constant parallelogram motion that maintains the orientation of the end-of-arm tool that handles the product. Delta robots can execute precise and fast motions because, unlike articulated-arm robots that have motors in each arm, delta robot motors are located in the main body above the work area. All movement comes from the extremely light robot arms, allowing for low inertia and fast acceleration for incredibly fast pick-and-place motion of lighter items. In 1998, not long before McGraw began looking for carton-packing automation, ABB introduced the IRB 340 FlexPicker, one of the first commercially available delta robots. This robot was capable of 10G acceleration, and exponentially faster than human operators in handling smaller items.
White Castle became an early adopter, installing one IRB 340 FlexPicker on each of the lines. Equipped with vacuum grippers and sophisticated motion control, each IRB 340 robot on the 12-ct carton lines picks six two-slider-packs at a time, while a newer IRB 360 FlexPicker on the 16-ct line picks eight two-packs at a time. In every cycle the robots pack a layer of two cartons simultaneously, with two pick-and-place iterations completing two cartons at a time.
While ABB’s delta robot portfolio has since been significantly upgraded and expanded with greater capabilities, longer reaches and higher payloads, each of the original IRB 340 models are still in operation today at the White Castle Louisville plant, some twenty-plus years later. “The ABB delta robots are the best investment we ever made,” says McGraw. “Their speed and accuracy keep the lines moving and they are highly reliable. We have taken great care to maintain them, and we will continue to do so. I think they will last a good while longer.” PW