Cutting costs automatically with automated material handling

The Stopa LG-B1.5 long-span shelving, which handles 5 to 6 tons of material per shift, is used to stock extruded aluminum sections at Schletter's Shelby, N.C., manufacturing facility.

Situation

Schletter Inc., a subsidiary of the German company Schletter GmbH, designs, develops, and produces solar mounting systems made of steel and aluminum for sale in North and South America. At its first U.S. plant, located in Tucson, Ariz., the storage of metal sheets and long materials had become a challenge. The material there laid in cantilever racks and was transported to the processing machines via forklift trucks.

The company realized a different material storage concept was required for the new facility it was building in Shelby, N.C.

“It was already clear in the early phase of building planning that we would be investing in automatic storage systems,” said Christoph Hackner, vice president of manufacturing. “The aim was to devise a sustainable and economical strategy for handling raw materials and semifinished parts.”

Resolution

The company invested in automatic sheet metal and long-span shelf storage from Stopa.

A Krasser Centurio system cuts the thin sheets supplied in coils to the required dimensions and pushes them onto a flat pallet resting on a scissor lift table. The table takes the sheets into the Stopa compact automatic store, where they are picked up by the two-mast storage and retrieval unit (SRU). More material is supplied by the operator to the store at a manual insertion station.

The sheet metal store, with dimensions around 169 by 27.5 by 18 ft., handles 6 to 8 tons of steel and aluminum per shift. Designed for metal sheets in large and medium formats and offering 781 pallet positions and two loading heights, the store supplies sheets to several machines, including a TRUMPF® TruLaser 5030 laser machine. It is linked to the store by a double car, comprising a charging car and discharging car in gantry design, and by an automatic handling unit. The double car takes sheets from the store to the machine and brings back semifinished parts.

The sheet metal store acts as a supply axis to the other systems. For example, a transport car takes laser-machined parts to a RAS Multibend center, which Schletter uses for upward and downward swing folding and which supplies a robot with sheets cut to size. In addition, two TRUMPF folding machines and a RAS shear are linked by transport cars. The material is transferred manually to the folding machines and the shear. Bar code scanners installed at the stations allow operators to scan the printed-out transport orders. At every insertion or return storage operation, a weighing unit records the weight.

The SRU reaches speeds up to 492 FPM during longitudinal movement, quickly covering the 167-ft.-long stretch between the 26 shelf towers of the store arranged in double rows. The operator can file slower acceleration and speed values in the main article data as required.

The Stopa LG-B1.5 long-span shelving, which handles 5 to 6 tons of material per shift, is used to stock extruded aluminum sections. Two hundred twenty-two large cassettes rated for a payload of up to 3,300 lbs. each, with a size of 2.72 by 2 by 21.7 ft., are used as load carriers. An overhead SRU inserts and retrieves the cassettes in the 12 aisles of the system.

The store uses four output stations to supply the linked-up saws operated manually, automatically, and semiautomatically. Requested sections are taken by the stations in automatic mode, monitored by scanners, directly to the saws.

Once the sections that were inside a long-span material cassette have been completely used up, the cassette goes to an empty cassette pool. From there the operator requests a cassette for new material and books the incoming goods onto it.

The company now can run unattended shifts at night and on weekends. Forklift traffic inside the building has been greatly reduced, creating a safer working environment while minimizing damage to materials. Internal logistics costs have been cut.

Volz-Stopa America Inc., 21 Bigwood Lane, Burlington, CT 06013, 860-675-5172, www.volz-stopa.com