Prototype on 2000 piles
For over a century, Droop+Rein has been making a positive contribution to mobility. Machining centres from Bielefeld are used to produce drives for submarines, ship motors and aircraft landing gears. However, a milling head from the FOG series is involved in one of the most unusual applications on a daily basis on Lake Constance. It is used to produce segments for pulley wheels for the global market leader in cable car construction.
"If we're talking about Droop+Rein, we'd certainly consider buying a second one". That's the short assessment of Karl-Heinz Zündel, Head of Production at Doppelmayr Seilbahnen GmbH from Wolfurt (Austria), and shows the company's satisfaction with the FOGS D40. It was made by Bielefeld-based Droop+Rein, a brand belonging to Dörries Scharmann Technologie GmbH (a subsidiary of the Swiss Starrag Group). The Austrian cable car manufacturer was impressed on a visit to German company Liebherr-Aerospace Lindenberg GmbH in Allgäu, where three machines from the same series manufacture landing gear components for aircraft. Zündel and his department manager, Klaus Meyer, particularly like the gantry concept.
For its specific application - turning, milling and drilling up to 13 meter segments for pulley wheels (drive wheels) - Doppelmayr ordered a larger, open unit of the FOGS D40 type with two working areas, something that Droop+Rein had never before produced in this type and size (20,000 mm x 9,400 mm x 6,900 mm). The travel distances on the multifunctional machining centre are 12,000 mm (X-axis), 4,000 mm (Y-axis) and 2,000 mm (Z-axis), with a travel angle of ± 200° (controlled C-axis). The machine table for the 135 ton unit measures 4,000 mm x 12,850 mm, while the rotary table has a diameter of 3,000 mm and is powered by two 60 kW AC motors.
Machines from the FOGS D40 series have a mechanical main drive with fork-type milling head and cartridge to hold the motor and gear spindles. The milling unit is made up of the cross slide, which can be moved in the Y-axis, and the fork head attached to the 40 kW slide feed milling unit (Z-axis, max. 6,000 rpm), which has an integrated C-axis. Doppelmayr had the machine fitted with an eccentric fork-type milling head along with an angled and a vertical milling head (each with 40 kW of power).
FOG machining center: Used by global market leader
High tech on the piste - Getting safely to the top - cut by cut
"We needed a significantly larger open machine with a travelling column design", says Zündel. "Because there was nothing like that available, we took the risk and bought a new development. It was also important for me that the machine would be valued by the people who work on it." Another reason why the machine is very popular with him and his staff is that its open design allows it to be cleaned easily with the integrated high pressure hose. Doppelmayr improved the ergonomics by installing foundation connection plates and cooling lubricant return channels.
In 2009, the Bielefeld company produced the prototype at the Hohe Brücke plant, which stands on 2000 piles due to the marshy ground. Since then, the innovative German solution has been cutting segments from solid, extremely hard to cut structural steel, with four elements plus the central section making up the pulley wheel. At the rear of the plant are the large heavy-duty cutting machines, which must not influence one another even when running flat out. A U-shaped foundation is used for the FOG series, offering excellent rigidity and having a lower depth than other types of foundation. This construction makes assembly easier, cuts costs and also has a positive impact on the "tool life". Department manager Klaus Meyer says: "The rigidity of the machine is a hugely important factor for us. The side milling cutters have an incredibly long service life."
