Benefits of robotic palletizing more measurable than in the past.

Robot manufacturers and integrators long have been able to quantify the benefits of robotic automation in many applications such as welding, assembly, grinding, cutting and painting. Such applications offer measurable results in benefits such as higher quality, higher throughput and cost savings

The benefits of some other robotic applications, however, aren't as transparent. Robotic palletizing, for example, is a relatively mature application of flexible automation, but it historically has been underused because of cheap labor and often difficult-to-measure costs associated with manual palletizing. But that's changing, with manufacturers finding it easier to measure the costs o f fewer labor options and rising workers' compensation claims.

"In the past, the drive to automate palletizing operations wasn't as strong because it was seen as a non-value added process, and there was a fair amount of manual labor available at economical rates," said Jack Justice, a market segment manager at Motoman Inc. "In applications like welding or machine tending, you can easily see an increase in quality, throughput and payback. In palletizing, it was harder to see payback at the end of the line. But, now, labor isn't as economical and workers' comp claims are higher for people doing end-of-line packaging and palletizing. Now, it's more advantageous to put in automation at the end of the line."

Those companies with fixed, or non-robot, palletizing automation also can benefit from switching to a robot-based palletizing system, where the main advantage is flexibility in handling boxes, crates and bags of numerous sizes and weights and building an array of pallet configurations.

"Companies that have some type of hard automation for palletizing should look at the cost of changeovers or how much downtime they're experiencing," said Mike Bomya, executive vice president for Nachi Robotics. "It's more of an incremental thing, but there's a huge benefit in flexibility with robotic palletizing systems. For customers' day-to-day operations, flexibility is important. Even if the products are very similar, they tend to have some variation by batch. With a robotic solution, there's virtually no cost penalty in changeover."

Flexibility, the hallmark of robotic automation, allows companies to palletize a variety of different cases (a robotic palletizing system can store an array of patterns) and more easily effect changeovers from one case size to another. In the past, however, that flexibility wasn't always enough to make the case for robotics. The need for speed to bit necessary cycle times sometimes kept companies from considering a robotic solution to their palletizing operation. That, too, has changed, with continued improvements in robot speed and performance, software and grippers.

"In the past, robotic palletizing systems worked in the intermediate level, and high-volume operations were still better for dedicated palletizing machines," Justice said. "But with the new high-payload robots, we can compete with dedicated machines and do it with a smaller footprint. Layers are formed on the incoming conveyor and the robot picks up and palletizes the entire layer at once, and does six to 10 picks a minute."

Another advantage of a robotic palletizing system that helps increase throughput is its ability to handle more than one infeed conveyor at a time. And the workcells can be configured to best fit the space available.

"There's quite a bit of flexibility in designing a robotic palletizing workcell," Bomya said. "And the robot can be mounted on the floor, inverted or side-mounted; there are lots of solutions."

"And it's good to keep the design as simple as possible," added Todd Babisch, an account manager with Nachi Robotics. "You want to get the product from Point A to Point B, and if you can do that simply, it makes the overall experience with a robotic system better."

Programming and software enhancements also make robotic palletizing one of the easier robotic applications for end users. Pack patterns can be created offline and downloaded to the robot controller which keeps downtime during changeover to a minimum.

Software also can be used in the initial design of a robotic palletizing workcell allowing the workcell designer, whether it's the end user, a systems integrator or a robot manufacturer, to build a virtual workcell, then configure it in different ways to find the one that works best and achieves the highest throughput.

"AutoPlace, in our MotoPallet software package, 'allows you to determine the best place to put the robot and other components in the workcell to get the best cycle time," Justice said. "In one instance, we ran it on a layout that was taking 96 seconds to build a layer. AutoPlace came up with a layout that took 92 seconds. That worked out to 24 more cases palletized each hour."

Justice also recommends that a company looking at a robotic palletizing solution for the first time look at the product being palletized to ensure successful implementation.

"Making sure you have good packaging is important," he said. "If you have a low-grade corrugated box, it can be fairly porous and needs a tremendous amount of vacuum to pick it up. You need less vacuum for higher-grade cardboard. You also want to design the end effector well so you don't lose the product. With heavy payloads, you can get side shear and the robot can lose control of the case. One solution, if you're using vacuum, is to design fold-down bars to keep the load from moving; or you can use side grippers or a combination of the two."

Finally, for smaller companies that might not be able to justify, afford or even need a large, custom robotic palletizing system, some robot manufacturers offer modular palletizing components for simpler, less expensive configurations, or pre-engineered workcells. Along with its PalletWorld system, Motoman, for example, had designed a smaller version, PalletWorld Lite, for smaller companies.

"PalletWorld Lite is offered with 20kg, 50kg or 80kg robot, depending on speed and payload of the application," Justice said. "The basic cell is under $80,000 with a 20kg robot, which is in reach of all the smaller shops that can't afford a full palletizing line."