The GS series of machining centres from Alzmetall is characterised by high dynamics and precision; it is mainly used for demanding machining tasks in high-volume production, tool and mould making, prototype construction and in the aviation industry. Alzmetall has found a solution for the energy supply to the spindle that is both economically and technically convincing: They obtain a harnessed, ready-to-install energy chain system from igus.
The Alzmetall GmbH in Altenmarkt, which is known as a market leader in the metalworking industry, has built up a range of machining centres since the 1980s that is in the upper segment in quality and performance.
The GS 800 was added to the machining centre product family in 2001, which was expanded in 2005 with the GS 1000 and finally extended downwards in September 2006 with the GS series. Hans Jürgen Gizler: Division Manager Sales for CNC machining centres: "For users who demand precision and performance that cannot be met by conventional frame designs, we offer the new GS 650." The machine is designed as a true gantry system and is offered exclusively with highly dynamic and maintenance-free torque drives.
High accuracies (Tp=0.007) and high machining speeds stand for the use in single part production and in series, in tool and mould making as well as in general machine construction.
Integration into automated production systems can be implemented with a linear robot solution - the machine can be fully craned from above - as well as with a pallet changer or an articulated arm robot for loading from the front - e.g. also with a zero-point clamping system.
For other components, the company relies on "outsourcing", i.e. cooperation with efficient suppliers - for example, for the energy supply systems that supply the spindle with energy, data and coolant.
The high requirements result directly from the high performance rendered by the machine. In rapid motion, the spindle travels at up to 60 m/sec and achieves an acceleration of up to 10 m/sec2. In free space, acceleration values of up to 17 m/sec2 are required. But a high number of movement cycles under continuous load also place high demands on the quality of the cables and cable guidance.
Alzmetall used pre-assembled readychain cable packages from igus for the first time in the GS 800. Since the cooperation has proven successful, the GS 650 will also be equipped with readychain systems.
This choice not only reduces assembly time, but also contributes to the durability of the energy supply system. Because the chainflex cables were specifically developed for use in energy chains: They allow small bend radii - which also permits compact installation situations - and are characterised by a long service life even under continuous movement stress. This is an important criterion for Alzmetall, because the machines are very solidly constructed. The spindle, which operates at up to 30,000 min-1 requires a total of 50 to 60 energy and signal cables - including electrical cables for servo drives, hydraulic hoses for the tool clamp, encoder and measuring system cables as well as supply cables for coolant and a compressed air supply to blow out the spindle. The readychain systems save valuable assembly time in the process.
The energy chain system of the GS 650 provides mobility in three axes. The x-axis moves separately, while the y and z axis overlap. Installation is very simple, as all three chains end in a distribution box supplied by igus. The x-axis is designed horizontally and uses the upper machine cover as a support, on which it is supported by a bridge: a design detail that saves space and ensures optimum guidance of the chain.
When developing the energy supply system for the GS 650, the project engineers benefited from the fact that a new energy chain series had just been launched on the market at that time: The E 4/4 light is characterised by very compact external dimensions ; the chain is 20 mm narrower with the same content. It was precisely these 20 mm that ensured that the chain remained within the machine contour during all movements. And despite the compact type and tight bend radii, the chains and with them the cables move at high speed.
Two variants were specified for the chain assignment: one for the standard versions of the GS 650, a second with additional cooling hoses for the more powerful spindle with 30,000 min-1. These versions, which are assembled in Cologne, are delivered by igus "just in time" to Altenmarkt. Of course, additional cables can be integrated into the chain if required. This can even be done retrospectively: an argument that also convinced the Alzmetall design engineers is the simple retrofitting of the energy chain if, for example, additional axes or minimum quantity lubrication is required. In this case, you simply snap open the individual chain links and place the cable in the channel provided for this purpose.
The readychain energy chains in Alzmetall's production halls are hard to miss: The ready-assembled chain and cable packages, including distribution box, take up barely more storage space than a Euro pallet. In order to keep an eye out for other igus products that Alzmetall uses, one has to walk very attentively through the assembly in Altenmarkt - and one finds them: iglidur plain bearings made of high-performance polymers with "built-in" lubrication are used in the tool magazine holders.