Robots are an excellent choice to transfer loads from one vehicle to another. For example, when moving items from a conveyor to a pallet, or making up an order on a pallet from items picked from several other pallets. “Robots are a fantastic piece of equipment to sit at one spot and combine available products into one individual load,” says Yves Gazin, vice president of solutions and product support at Egemin Automation.

“We typically use robots when a change in orientation of a specific package is required,” reports Paul Moore, director of systems sales for FKI Logistex. “For direct transportation, a robot is not a cost-effective means for moving from one point to another point, but if you do need to orient the product, pick the product up off a conveyor and place it into a machine, pull it out of a machine, or put it into a case, the robot is very good.”

Robots start with the classic articulated arm models we’re used to seeing around automotive assembly lines. While these have grown eyes, brains and the ability to work together, even more versatile are free-form systems whose structures and dynamics follow exactly the needs of the task at hand. Most often, those structures take the shape of a gantry made up of two trundles or “bogeys” moving on parallel rails, which support a large crosswise “bridge” carrying a third bogey providing the robot’s second degree of freedom. A hoist or crane dangling from the bridge bogey provides the third spatial degree of freedom.

Moore also points out that in the last five years, there has been a trend to extend robots’ reach by mounting an articulated-arm robot on a servo-driven track so it can reach an extended number of positions. An example would be for tending multiple machines or for palletizing to multiple positions, which wouldn’t fit in the traditional robot work envelope.

Delta robots have a spider-like structure that uses clever geometry to provide stiffness with little mass, making them light and fast. They still have limited spatial range and payload capacity, but move those loads within that envelope with surprising speed and agility.

Smart conveyors seldom have belts anymore. Typically they drive loads via computer-controlled rollers that can speed up, slow down, and even steer packages to arrive at the right place at the right time.

“When moving material over very short distances and with extremely high throughput,” says Yves Gazin, vice president of solutions and product support at Egemin Automation, “it is much better to use a conveyor system. The congestion you would create with a number of vehicles moving back and forth make AGVs impractical. If the distance becomes too small, on the other hand, you’re not going to do it with forklift, but with a piece of conveyor.”

Similarly, installing a robot just to move stuff from A to B does not make economic sense if the distance is beyond its movement range. You may have a robotic handler at each end of the conveyor, but not just to traverse the space between.

“In the last five years,” says Paul Moore, director of systems sales for FKI Logistex, “we’ve seen a huge growth in smart conveyors. These conveyors are typically powered with 24-V rollers, and are very flexible.”

There are several reasons customers like to use them. When humans are present, such roller conveyors are inherently safer. There are a series of small motors built into roller sets laid out on three-foot centers. One roller is driven and the others slave off it. The roller sets’ motors are separately energized under command of a local controller.

This system provides a number of advantages. Safety is enhanced by having a number of relatively small independent drive motors, rather than one huge monster pushing the whole conveyor. Should a human tangle with the conveyor, the small motor driving just one roller set can do relatively little damage. The system can save energy by driving only when there is something to drive. In between individual loads, the rollers in a section can be powered down to save energy.

Another advantage is easier reconfigurability. When a conveyor is built with one large belt, that assembly must run a certain distance, and modifying the route by, say, introducing a new divert point in the middle, would require building an entirely new conveyor. With short powered-roller sections, it is possible to just yank one section out and install the diverting equipment.

Maintenance is easier because a mechanical or electrical failure only involves one small section, which is easier to remove and replace than an entire conveyor.

Finally, these computer-controlled conveyor lines allow on-the-fly package diversion. It is now possible to combine and split material flows, sending different items to different destinations and bringing items from different sources together for one destination.

What makes this possible is the ability to individually identify and track packages combined with sophisticated warehouse management software.

“One of the new products we’ve recently introduced,” says FKI’s Moore, “is a software package that allows us to space cases very closely going into a sorter. We can merge from multiple lines into a stream feeding a high-speed sorter at up to 400 cases per minute.”

Try THAT with a belt conveyor!

“With lean manufacturing everyone’s initiative, everyone wants to reduce the number of conveyors, but they still remain the most cost-effective way to transfer product from one point to another point,” Moore says.