Smoothly from warehouse to warehouse

The AGVs communicate with the shelves via WLAN and move using laser navigation. They help to improve cleanliness and safety in the sometimes very cramped aisles of the traditional production halls. Rolling bearings have been manufactured in the old industrial town of Steyr since the 1940s. The Steyr Wälzlager plant has belonged to SKF AB since 1988. The Swedish technology group develops bearings and bearing units, seals, mechatronics, services, lubrication systems and measurement technology.

Minimizing frictional losses with innovation

Steyr is also home to the Quality Technology Center (QTC), a competence center for measurement technology within the Group. The inner and outer rings ground in the channels (production lines) are then married in the production line and completed with purchased components to create finished rolling bearings. "There are around 3,000 different components in our component warehouse," says Peter Holzmayr, Packaging Manager at SKF Österreich AG.

Component provision problem

The components are transported to the channels in standardized transport containers, as is the transfer of the finished bearings to the central warehouse in Schweinfurt. Until May 2013, they were transported exclusively by forklift truck. "The entire material required for an order was usually delivered at the same time," says Peter Holzmayr. "This was unsatisfactory, presented a veritable space problem and involved time-consuming searching and maneuvering that was difficult to plan." Some of the corridors only have one lane of traffic and, in addition to the forklift traffic, pedestrians also had to be taken into account.

"With the AGV, we succeeded in smoothing the material flow in ball bearing production while at the same time improving order, safety and cleanliness."

Peter Holzmayr Manager Packaging Industrial Drives Business Unit, SKF Österreich AG

Photo: DS Automotion

In 2011, SKF Österreich AG decided to introduce just-in-time supply of the channels using driverless transport systems in order to achieve a high safety factor and improve intralogistics. The decision was made in favor of DS Automotion GmbH. The Linz-based company has specialized in the development and production of automated guided vehicles (AGVs) for more than 30 years and has become one of the world's leading suppliers in this segment.

Material is provided on channel shelves

An essential part of the project was the division of the material flow. The components coming from different sources in the warehouse are provided in 132 individually monitored storage locations on a central transfer rack. From here, they are transferred to smaller racks at the edge of the individual channels for further processing. The channel racks have replaced the previous staging areas and provide a separate bin location for each type of component, as well as for finished roller bearings, waste or empty bins, which are staged here for return transportation.

"The fact that the channels now receive the material in containers keeps the quantity manageable and reduces the time required to remove the material as needed," says Peter Holzmayr, citing a key effect of the changeover. "Transportation is carried out using driverless transport vehicles from DS Automotion, which move exclusively indoors and thus keep dirt away from our production area."

Intelligence in navigation

The driverless transport vehicles are automated high-lift trucks with laser navigation based on the EGV-S from Still. The vehicle produced by DS Automotion has already proven itself in almost 30 systems. "The heart of the AGV is the M-Box control computer, which was developed in-house on the basis of an industrial PC running Linux," says Christian Huemer, Head of Automation Series Devices at DS Automotion. "It steers the vehicle along the route segments received from the Eurotrans master computer and checks the course using laser bearings from reflectors along the route." In addition, integrated safety circuits evaluate the signals from the built-in PLS safety laser scanner and ensure safe stopping in front of obstacles.

"The biggest challenge in designing the system with two freely navigating vehicles was the limited space in some aisles," reports Christian Huemer. "It forced the developers at DS Automotion to make a special effort when designing the route."

More security

"By reliably stopping the vehicles in front of obstacles, the DS Automotion solution has noticeably increased passenger safety in the aisles," reports Peter Holzmayr. "Block handling in front of bottlenecks also means less time is lost due to the orderly waiting of a vehicle in oncoming traffic than in forklift operation."

The goal of increasing efficiency by smoothing the material flow within the production plant was also fully achieved. Since the changeover to the DS Automotion system, the production lines have been supplied with pre-products on demand in three-shift operation. Thanks to the permanent, transparent material flow, the buffer areas on the production lines have been reduced, as has the time and effort required to remove the parts.

Satisfied into the future

SKF Austria is continuously integrating additional channels and, in future, other stations into the system. "From the initial inquiry to commissioning and beyond, DS Automotion provided us with the best possible support in making the project a success," says Peter Holzmayr. "We will probably turn to the Linz-based company again for future projects."

www.skf.comwww.ds-automotion.com