In mass production, classic interlinked conveyor technology is the most efficient way to achieve automation. In customized production, on the other hand, requirements are changing - the keyword here is batch size one. This is where the flexibility of automated guided vehicle systems (AGVs) comes into its own. At the American headquarters of SEW-Eurodrive in Lyman, South Carolina, a flexible production facility has been created that is optimized precisely for this individual production: classic conveyor technology has been combined here with flexible workstations. The autonomous vehicles drive independently through the hall, pick up pre-assembled gearboxes from a conveyor belt and bring them to the workers. The employees can now carry out further assembly on the vehicle itself - just like on a mobile workbench. The vehicle then drives to the next station and transfers the gearbox back to a conveyor belt. In this way, individual gearboxes can be assembled while processes remain efficient and flexible.

Under the Maxolution System Solutions business unit, SEW offers scalable and future-proof system solutions in the field of mobile and rail-guided conveyor technology. As a total solution provider for driverless transport systems, the focus is not only on the vehicles themselves, but also on the associated services - from system planning to commissioning and service. Vehicles and system components are produced at SEW-Eurodrive's headquarters in Bruchsal. In parallel to the globally renowned SEW modular system for geared motors and electronic products, the engineering of the autonomous vehicles is also based on an innovative modular technology and software system. This makes it possible to configure individual vehicles while keeping complexity to a minimum. "Our portfolio ranges from low vehicles with and without a lift, which in many cases simply replace a forklift truck, to assembly assistance vehicles and vehicles with collaborative robots on them," says Aaron Bronner, engineer at Maxolution and responsible for the design and development of the vehicles. "We often build customized vehicles that are designed for a specific application." Just like the vehicles for the production plant in Lyman.

Toothed belt conveyor as LAM

In order to be able to pick up the geared motors independently from a conveyor belt and return them later, the vehicles require an appropriate powered load handling attachment (LAM). "We initially thought of a chain conveyor that we could integrate into our vehicles," says Aaron Bronner. However, together with the conveyor technology experts from MK Technology Group, the team found a better solution. "Instead of a chain conveyor, we opted for a two-strand timing belt conveyor," explains Ulrich Klein, a sales representative at MK who supported the project. A toothed belt conveyor is cheaper and requires less maintenance than the originally planned chain conveyor. In addition, the timing belt has a higher grip than the chain. This also means greater stability for the product on the vehicle - even on sharp bends or an abrupt stop, such as an emergency stop. The ZRF-P 2010 timing belt conveyor from MK was the ideal solution for the project: it can safely carry the maximum load of 160 kilograms. The available drive variants also enable reversible operation in both directions.

Installation of the customized toothed belt conveyor ZRF-P 2010 from MK with modified center drive. © mk Maschinenbau Kitz /SEW Eurodrive

"The Maxolution vehicle fleet with the integrated LAM from MK plays a key role in implementing the Industry 4.0 approach at the site. The high degree of automation makes work much easier for our employees," emphasizes Rainer Neufeld, Corporate Electronics Manager and Project Manager for the AGV fleet in the USA. "The vehicles transport our geared motor kit to various stations over a distance of several kilometers per day. The precise and reliable transfer of the trays with the help of the MK-LAM is very important here."

Conveyor has a modular design

"There were a few technical challenges with the project," recalls Ulrich Klein. Due to its integration into the vehicle, the motor was not allowed to create any interfering contours on the outside. In addition, there had to be a free space between the two conveyor lines for the protruding output shaft of the gearbox. The motor therefore had to be positioned between the lines underneath the conveyor. Here, the MK designers were able to use a modified MK center drive. "After the initial inquiry, it took us around two weeks to fully specify the conveyor and clarify the installation situation in the vehicle," says Aaron Bronner. "That went really quickly and worked wonderfully. As the MK conveyor also has a modular design, it was easy to adapt for the planned application and integrate into the vehicle."