FILL collaborated with SHW to develop FIBROMAX universal gantry milling machine

How can precision components up to 60 t be manufactured rationally in the lowest possible quantities? Machine and plant builder FILL from the Austrian town of Gurten in the Innviertel took control of the situation itself without further ado. Together with large machine specialist SHW, it developed a universal gantry milling machine that can process workpieces that weigh tons both precisely and efficiently. At its heart is a practically maintenance-free positioning table with a large roller bearing from the rotary table specialist FIBRO.

The enthusiasm of Günter Redhammer, Team Lead for Parts Manufacturing, for the the SHW PowerBridge concept is clear to see from the first moment on. It’s no surprise: The over 21m-long, universal gantry milling machine with orthogonal milling head, two processing bridges, travelling tool robot, and control stand, as well as synchronous tool change and automatic milling head change permit extremely short setup times and precise results in small-batch manufacturing.

Setup time of just just a few minutes

Photo by FIBRO GmbH

Instead of setting up the extremely heavy components onto a machine support system with a lot of effort using a crane and dial, which can take several hours at the best of times, the parts are now set up on pallets outside of the machine during the main productive time. Using a zero position chucking system, they can be switched over to the FIBROMAX heavy-weight positioning table in just a few minutes. “As a manufacturer of large individual parts, I have to make sure that I make use of the non-productive times outside of the machine,” says Günter Redhammer. This is possible with the combination of the zero position chucking system and positioning table. “As soon as the pallet is chucked, we slowly move the workpiece on one side and then the other and finally align the FIBRO rotary table precisely with the workpiece. And now we can already start milling.”

Economic large component manufacturing

Photo by FIBRO GmbH

With their high rigidity and optimum flow of force, FIBROMAX NC rotary tables are especially designed for the flexible positioning of heavy loads. The latest version, FIBROMAX 2.0, is available in four sizes with diameters of 1,250, 1,800, 2,500 and 3,200 mm for transport loads of 25, 50, 100 and 400 t. A large, maintenance-free roller bearing takes up both radial and axial forces in the case of the XXL rotary tables. When in a positioned state, hydraulic table top clamping also increases the tangential torque and relieves the gearing. In contrast to rotary tables with hydrostatic bearings where the table top is raised with each cycle, the price/performance-optimised FIBROMAX 2.0 requires no hydraulic power pack and no cooling. Instead, the roller bearing reliably takes up axial forces reliably without the risk of thermal distortion. In case the power suddenly fails, the bearing function is not affected. Together with the play-free twin drive, the rotary tables also allow circular milling and simultaneous machining.

Precision, efficiency, and short delivery times

Photo by FIBRO GmbH

For good reasons, FILL decided to implement a new machine concept: On the one hand, geometrical deviations occurred again and again during the processing of base frames on travelling column machines. On the other, manufacturing efficiency was to be increased. And ultimately, the company wanted to free itself from the somewhat overlong delivery times when large components had to be manufactured externally. “We usually have a four to six week period from drawing to manufacturing. This is not possible on the free market in the case of large components. We thus had to find our own solution and become in dependent,” FILL Managing Director Wolfgang Rathner says. “Nowadays, it is not necessarily the cheapest company that gets the order, but more often the fastest.”

FILL did not find much in regard to large gantry milling machines on the market, according to Rathner. Machines with hydrostatic bearings have the right precision, but are often unjustifiable in cost accounting. In turn, more affordable machines often have deficits in precision and flexibility. The decisive question was: Why couldn’t FILL build the machine itself? “We already build small gantry milling machines, like our FILL SYNCROMILL. Mechanical and electrical engineering, mechatronics – these are all skills that we have,” says Rathner. That SHW had just completed its first concept for a universal XXL gantry milling machine came at just the right time for FILL. Together, they tailored the concept to the special requirements for flexible manufacturing, whilst focusing on high quality and performance, high precision, and an attractive price. SHW took over the centralised components like the bridge, capstan head, milling head, and toothed rack drives of its UniForce travelling column machines and adapted them for PowerBridge. The excellent machining performance, precision, productivity, reliability, and flexibility of the SHW travelling column machines were transferred to the gantry concept to some extent. The heavy-weight table of FIBRO rounded off the concept.

For more information, please visit http://www.fibro.de.

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