Modular energy supply system for revolutionary multi-spindle lathe from DMG Mori

Profile

• What was needed: rotating energy supply system in the drum and six linear energy chains; supplied as a pre-fitted readychain solution
• Requirements: high travel speeds and accelerations with high precision; many cables had to be guided safely in a small installation space; modular system that is easy to maintain
• Industry sector: machine tool manufacturing; multi-spindle lathe
• Success for the customer: the rotating energy supply system in the drum can follow rotation angles of up to 540° and allows a reverse bend radius; the chain systems can be plugged in individually and are easy to maintain and modify, thus enabling a high degree of modularity and simple maintenance.

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Problem

The MULTISPRINT from DMG MORI was presented as a revolution in mechanical engineering at the world's largest machine tool trade show, the EMO in Hanover. It is the first machine to combine an automatic multi-spindle lathe with SWISSTYPE technology featuring a Y-axis on each spindle position.
The MULTISPRINT sets new standards in terms of productivity and efficiency. The customer enjoys maximum flexibility for the mass production of components with a diameter of up to 50 millimetres.
The heart of the machine is the spindle drum with six spindles for simultaneous machining of several workpieces. The main spindles in the drum have a travel of up to 180 millimetres. The drum moves the workpieces to the tools quickly and very precisely. It only takes 0.65 seconds for one of the six spindles to travel to the next position. For spindles to return to the starting position after machining has been completed in the six stations, the drum has to turn 300° in reverse. For this, the unit, which weighs over three metric tons, only needs one second. The rods are pushed out of the loader through the drum to get into position for machining.
However, when the machine manufacturer was looking for a suitable energy supply system, it was not only the travelling speeds and accelerations of the drum and the high precision that mattered. As the working space for the mechanics behind the drum was kept as large as possible, the solution had to guide the large number of cables in a relatively small installation space. Most recently, the focus has been on maintenance and service. The solution had to be modular and therefore easy to maintain and adapt.

Solution

One of our rotating energy supply systems was used to keep up with the rotation of the drum. These are custom-made systems for circular movements with energy chains, which are used in machine tools and construction machines, among other things. The standard rotary modules consist of two circular guide elements. One part of the guide trough is attached to the stationary part of the system and the other part to the rotating part. The reverse bend radius enables movement of the energy chains in two directions. Rotation angles of up to 540° on one plane can be made possible here.The drum in the MULTISPRINT consists of two rotation systems. The hoses are located in the outer system, while 24 cables are guided in the inner circle - twelve encoder cables and twelve servo cables. Six installed linear chains each accommodate two encoder and two servo cables. One of the servo cables supplies the energy for the linear movements of the main spindles in the drum and one drives the spindle motor.
Developers made sure that the individual components were modular. The linear chain systems can be plugged in individually and are easy to maintain and modify. Also, the sheet metal parts we designed for attachment to the machine are made from several parts. This makes it easier to handle the readychain at the customer's premises and to harness it in our factory. The solution therefore fulfils all the requirements regarding ease of installation. Finally, the chains and cables of the completely pre-fitted readychain® solution also make do with the relatively small installation space of the machine.

Up to twelve MULTISPRINT machines can be manufactured simultaneously in DMG MORI's new production hall in Brembate di Sopra.

A look inside the MULTISPRINT shows the complex energy supply system from igus fully assembled on the machine's spindle drum.

To install the pre-fitted cables in the energy supply chains and the metal guides, the technicians in Cologne need approximately 2.5 days.