Compact energy chains in Alzmetall machining centres

• What was needed: ready-made readychain systems from igus consisting of E4/4 Light energy chains and associated chainflex cables, iglidur plain bearings
• Requirements: High travelling speeds and accelerations, compact installation situation requires tight bending radii, continuous load
• Industry: Machine tool construction
• Success for the customer: The E4/4 light energy chain offers particularly compact external dimensions and is also particularly robust, the readychain system saves assembly time and costs and makes installation considerably easier for the customer

Alzmetall GmbH in Altenmarkt, which is known as the market leader in the metalworking industry, has been building up a range of machining centres in the upper quality and performance segment since the 1980s. 
In 2001, the GS 800 was added to the machining centre product family, which was expanded in 2005 with the GS 1000 and finally extended downwards in September 2006 with the GS series. Hans Jürgen Gizler: Head of Sales for CNC machining centres: "We offer the new GS 650 for users who demand precision and performance that cannot be met by conventional frame designs". The machine is designed as a genuine gantry system and is offered exclusively with highly dynamic and maintenance-free torque drives.
High accuracies (Tp=0.007) and high machining speeds are ideal for use in single part production and series production, in tool and mould making and in general mechanical engineering.
Integration into automated production systems is possible with a gantry 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. with a pallet changer. For example, this can also be realised with a zero-point clamping system.
For other components, the company relies on "outsourcing", i.e. co-operation with efficient suppliers - for example, for the energy supply systems that supply the spindle with energy, data and coolant.
The high requirements are a direct result of the high performance of the machine. In rapid traverse, the spindle travels at up to 60 m/sec and achieves a maximum acceleration of 10 m/sec2. In free space, acceleration values of up to 17 m/sec2 are even required. However, a high number of movement cycles under continuous load also place high demands on the quality of the cables and cable routing.

Alzmetall used pre-assembled readychain cable packages from igus for the first time on the GS 800. As the co-operation has proved successful, the GS 650 will also be equipped with readychain systems.
This choice not only reduces assembly time, but also contributes to the longevity of the energy supply system. This is because the chainflex cables have been specially developed for use in energy chains: they allow small bending 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, as the machines have a very solid design. The spindle, which operates at up to 30,000 rpm, requires a total of 50 to 60 power and signal lines - including electrical lines for servo drives, hydraulic hoses for the tool clamp, encoder and measuring system lines as well as supply lines for cooling lubricant and a compressed air supply for blowing out the spindle. The readychain systems save valuable assembly time.
The energy chain system of the GS 650 ensures manoeuvrability in three axes. The x-axis moves separately, while the y- and z-axes are superimposed. Assembly is extremely simple, as all three chains end in a distribution box, which igus also supplies. The x-axis has a horizontal design 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 the time: The E 4/4 Light is characterised by very compact external dimensions; the chain is 20 mm narrower with the same capacity. It is precisely these 20 mm that ensure that the chain remains within the machine contour during all movements. And despite the compact design and tight bending radii, the chains, and with them the cables, move at high speed.