Power and signal supply for gantry loaders: High speed, smooth running

Problem

Today, the Gehring Group is one of the global market leaders in precision machining. The plant manufacturer designs special horizontal machines for drilling up to 15 meters and transfer lines for the production of engine blocks. These machines not only take care of the honing, but also other work steps such as the dumpling of coolant residues and cleaning. Everything with high throughput: With cycle times of almost always less than one-minute, high requirements for availability in 24/7 operation must be met.
Since users today want the greatest possible flexibility, the transfer lines in particular have changed. The engines are getting smaller, the product life cycles shorter. Priority is given to building individual machine modules that have to be connected via gantry loaders.
In order to also offer such gantry loaders, Gehring expanded its business area in 2014. Today, the plant manufacturer offers a modular system for gantries that enables the combination of different slides, vertical axes, loading systems and grippers.
However, there was a major challenge for the energy supply of these portals: a modular machine for honing the crankshaft bore can be up to 8 meters long. The cylinder modules take up 2.60 meters and for reasons of accessibility, 3 meters of space are required for each. This means that the portals manufactured so far – and thus the travel paths of the energy chain – are 20 to 33 meters long. The load is also impressive: In a current project, the gantry travels at 3 m/s and an acceleration of 7 m/s². However, portals for 10 m/s have also been built, which are used in a crash test bench.

Solution

When choosing the energy supply system for the portals, the Gehring designers used our energy chains including guide troughs and chainflex cables. Delivered as so-called readychain systems, the e-chains are already assembled ready for installation. This means that Gehring passed on the necessary design data to us, we laid out the e-chain, manufactured, equipped and assembled it and finally delivered it ready for installation including cables.

Since the demanding combination of long travel, high travel speeds and long service life (ten years is required) cannot be achieved with a sliding chain, we specifically recommended that Gehring use the P4 series profile roller chain. Here, the rollers of the upper and lower runs do not run on top of each other, but are offset on a continuous, wide rolling surface. This enables smooth, even running even over long distances of up to 800 m.

The autoglide bars ensure safe guidance, while at the same time significantly reducing the required drive power and increasing the service life.

For the energy supply from the portal, i.e. the X-axis, to the chargers (Z-axis), a chain from the E4.1 programm is used. Here, the rear grip in particular ensures significant lateral stability compared to conventional systems.

Finally, our chainflex cables are also used for mobile applications. Gehring uses the CF27 servo cable series for the fast X-axes, which is characterized by an additional pressure-extruded TPE inner jacket, among other things. We give a guarantee of 10 million cycles or 36 months on these. For data transmission, cables of the CF113 series are used, whose expected service life is even 20 million cycles in the specific case.

The energy supply system contributes to the high availability of the gantry – in three-shift operation at 160 strokes per hour.