Compact energy chains in Alzmetall machining centres

Profile

• Requirements: High travel speeds and accelerations, compact installation situation requires narrow bend radii, continuous load
• Industry: Machine tool manufacturing
• Success for the customer: The E4/4 light energy chain offers exceptionally compact external dimensions and is at the same time particularly robustly built; the readychain system saves assembly time and costs and makes installation considerably easier for the customer.

The Alzmetall GmbH in Altenmarkt, which is known as a market leader in the metalworking industry, has built up a range of machining centers since the 1980s that is in the upper segment in quality and performance. 
The GS 800 was added to the machining center 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 centers: "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 mold 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.

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. They allow small bend radii - which also permits compact installation situations - and are characterized 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 characterized 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.

The spindle of the machining centre must be connected to numerous energy, signal and media cables. This task is undertaken by the "readychain" energy chain systems.

An intelligent design detail: the x-axis of the energy chain is horizontal and uses the upper machine cover as a support. This saves space and ensures optimal guidance of the chain.

All three e-chains are connected via a distribution box, which igus also delivers, simplifying assembly even more.

Alzmetall also uses plain bearings from igus - for example in the holders of the tool magazines with which the GS series can be optionally equipped.