Palletizer does double duty

Guida's Milk & Ice Cream, New Britain, CT, is one of the largest independent dairies in New England. Since 1886, Guida's has had the reputation of supplying the finest products and service to its large customer base. With its fleet of more than 200 vehicles, Guida's Milk & Ice Cream delivers fresh dairy and dairy-related products throughout southern New England. Its service area includes Massachusetts, Rhode Island, Connecticut, northern New Jersey and New York State, including Long Island. With an 18-day code on all of its fluid milk products, Guida's can guarantee the utmost integrity of its product line. The company also processes a full line of ice-cream mixes, fruit juices, fruit drinks and water to meet virtually all of its customers' needs.

Until recently, the dairy's production line ended with manual palletizing of its 8-oz to 1-gal milk products. Employees, who were needed elsewhere in manufacturing, were required to do the physically demanding and potentially dangerous work. The company needed to find a solution that would increase the efficiency and speed of the operation and provide a safer working environment for employees. Guida's turned to its partner, Dyco, Inc. (www.dyco-inc.com), to develop a solution. For the past 10 years, Guida's has been working with Dyco, a leading manufacturer and integrator of turnkey container-handling systems, for all its handling needs.

Dyco had recently developed a new palletizing system using robotics and, after evaluating the dairy's operations, suggested a fully automated palletizing system using a Kuka KR 180 PA robot from Kuka Robotics Corp. (www.kukarobotics.com). The company's new automated system is being used to palletize two lines of milk products. Depending on production demands, the Kuka KR 180 PA robot runs from 12 to 16 hours a day, six days a week, making the dairy more productive and efficient. Additionally, the new system has allowed the company to free up two employees who are now assigned to less physical and more intellectually demanding projects elsewhere in the dairy. This increases job satisfaction and safety for the employees, while increasing production speed and accuracy for the company.

On one production line, the milk is filled into half-gallon or gallon jugs, depending on which product is being produced that day or that shift, and is conveyed to the palletizing cell. Eight 1/2-gal jugs or four 1-gal jugs are placed in corrugated cases, which are then conveyed to the Kuka KR 180 PA robot to be palletized. Simultaneously, on a different filling line, either 10- or 16-oz, single-serve bottles are being filled and placed into tray-packs. Twelve 10- or 16-oz containers are placed into the tray-packs for transport via this second conveyor line to the palletizer. The two conveyor lines enter the palletizer area, one above the other, and one line wraps around the back of the robot, resulting in a conveyor on each side of the palletizer.

The new system has a pallet conveyor on each side of the robot that slides an empty pallet into place. The pallets are fed to the robot by a pallet dispenser that holds about 25 pallets and dispenses them out the bottom one at a time. The robot cell, controlled by a centralized programmable-logic controller, palletizes product onto each of these two pallets.

The gallon cases are palletized four cases at a time, three rows per layer and four layers per pallet, for a total of 48 cases per pallet. The 1/2-gal cases are palletized five at a time, three rows per layer and four layers per pallet, for a total of 60 cases per pallet. The pint and 10-oz packs are picked four at a time, 20 packs per layer. Pallets of pints contain 120 packs, and the 10-oz packs are palletized at 180 packs per pallet. When it is running at full speed, the robot can make seven picks per minute, turning out a full pallet in less than four minutes.

The smaller, tray-packed products come into the cell at a faster speed. To compensate, the robot is programmed to palletize some product from Line One and then some from Line Two, alternatively picking up from the two lines until there are two complete pallets.

An additional unique feature of the robot is its ability to assemble partial pallets of the products it is palletizing, thus allowing the company to palletize and ship less-than-full pallets per its customers' specific purchase orders without additional labor costs. Additionally, the robot has the ability to intersperse slipsheets (thin pieces of paperboard approximately 40 346 in.) between case layers to provide stability to the finished pallet. Once a pallet is complete, the pallet-conveyor system moves the pallet out of the cell to a stretch-wrap cell, and a new empty pallet takes its place.

The Kuka KR 180 robot used in the operation is a four-axis robot with a passive fifth axis, whose application-specific, kinematic system guarantees an efficient palletizing process. It is specifically designed for high-speed, heavy-payload palletizing/handling tasks, up to 180 kg. The robot's large working envelope and small footprint enable it to service several conveyors with a minimum space requirement. Its arm is made of carbon-fiber-composite material, giving it a smaller moment of inertia and, thus, allowing the arm to achieve excellent acceleration rates. Despite its lightweight construction, the arm demonstrates extremely high stiffness characteristics, allowing the KR 180 PA to stack loads weighing up to 180 kg to heights up to 3,000 mm at rates as high as 1,800 palletizing cycles/hr.

Guida Dairy's new, automated operation has allowed the company to increase production, efficiency, throughput and job satisfaction, while decreasing work-related injuries. Dyco's integration expertise, coupled with Kuka Robotics' high-performance, high-speed robot, successfully met and exceeded the dairy's palletizing challenge.