December 2008

Robots in packaging: It's all about cost savings

When Guida's Milk & Ice Cream out of New Britain, Conn., decided to automate palletizing for two lines, they chose a robotic system with a robot that runs 12 to 16 hours per day, six days per week. On one side, it picks up corrugated cases containing eight half-gallon or four-gallon jugs and stacks them on a pallet. The system picks up gallon cases four at a time and places them in a row on the pallet. Each layer has three rows, and pallets stack four layers high for a total of 48 cases.

This is just one example of how robotic palletizing is quickly growing in popularity among packaging lines. Equipment builders are delivering more turnkey systems, creating more modular designs, replacing pneumatics with electromechanical devices, and automating inspection tasks in an effort to accelerate changeover, increase speed, boost efficiency, simplify integration, lower costs, and meet expectations for consistent product quality.

With the ability to handle everything from caps to pouches to torque converters, robots can meet the needs of multinational and smaller packagers and are seeing increasing use among companies with 100-200 employees. Due to their smaller footprint and superior precision over conventional palletizing technology, robots can offer major advantages for smaller packagers with low-speed packaging lines.

These systems can handle Guida's four-layer, half-gallon case stacks five at time and arrange them in four rows per layer for a total of 60 cases per pallet. On the other side of the work cell, 12-count trays of 10- or 16-ounce bottles arrive on a second line. The robots pick them up four at a time and arrange them in layers of 20 cases. The 10-ounce bottles are stacked nine layers high; the 16-ounce bottles go six high. Since the trays of the smaller containers arrive more frequently, programmers can set the robot to alternate between the two lines and build two pallets at a time.

The robot can insert slip sheets between layers to enhance the stability of the final load and can also build partial pallets for specific orders. A pallet handling conveyor completes the system, delivering empty pallets to the robot and transferring full loads to an adjacent stretch wrapping cell. Installation of the robot cell made it possible for the dairy to reassign two workers to less physically demanding work.

Underlying factors

Labor savings is a major driving force for the growing use of robotics in the packaging industry. By using a robotic palletizer, Johnson & Johnson was able to reduce labor costs by up to 60% at its Montreal personal care products production facility, said Michel Cousineau, project group leader at Johnson & Johnson in Montreal.

Ergonomics and flexibility are also big influences. One maker of tire mounting/demounting and pipe joint lubricants based in Solon, Ohio, uses a robotic palletizing cell, just as in Guida's installation. This palletizing cell, anchored by an articulated robot, handles two packaging lines. A vacuum end effector makes it possible for the robot to handle 25- and 40-pound pails as well as quart or gallon containers in cases, plus a variety of stacking patterns and pallet sizes.

In a typical 7.25-hour shift, the robot handles either 60 pallets of 25-pound pails, 20 pallets of 40-pound pails, 40 pallets of quart cases, or 25 pallets of gallon cases. The robot, which is only working at 65% capacity at present, has provided a 55% productivity gain compared to hand stacking, freeing the crew to complete other activities.

In some cases, a robot performs multiple tasks. The ability to handle multiple products in a compact space is the driving force behind increased use of robotic case packers and palletizers. These machines range in complexity between handling six, eight, and 10 product variations simultaneously to handling as many as 50.

Another robotic application generating interest is order picking and assembly of mixed pallets. Advanced software and automating mixed pallet building may require integration with vision and tactile sensors as well as sophisticated communication technology. Higher speeds are also possible through improvements in mechanical design and robot controllers with better motion architecture. Adding vision systems supports higher rates by making it possible for the robot to pick up more than one item at a time.

Lower costs

Along with flexibility and easier integration, packagers are looking for lower cost machinery. Concerned about shrinking margins, reduced productivity, and overseas competition, these packagers are looking for ways to automate, increase throughput, and reduce costs, demanding machinery that can be tailored to meet very specific functionality requirements.

The demand for less expensive equipment has resulted in quite a cost reduction for robotics. One supplier has developed a lower cost, low-level palletizer capable of handling up to 20 cases per minute. Designed from the ground up for efficient manufacture and assembly, the palletizer can change over in less than 10 minutes without tools. Another way packagers are lowering costs is to drop requirements for specific controls and allow original equipment manufacturers to match control to performance requirements.

Another cost savings measure is using integrated motors and drives. Miniaturizing a servo drive and placing it on top of a servo motor reduces the size of the electrical cabinet needed and shrinks the machine footprint as well as the amount of wiring required. This is especially significant in applications where cabinets appear up in catwalks and require lengthy amounts of cabling. This can quickly add up to a 40% reduction in machinery price.

SOURCE: "Automation Trends: Robotics," a Packaging Intelligence Brief from The Packaging Machinery Manufacturers Institute, a manufacturing trade association in the U.S. and Canada (www.pmmi.org).