User reportFlexible and durable: 3D-e-chain® for CNC multi-spindle automatic lathes from Schütte

• What was needed: multi-axis energy chain triflex® R-Type TRL 60
• Requirements: To supply the spindle, the cable guide had to be able to perform a very fast rotational movement in addition to the axial feed. At the same time, it must be able to reliably perform more than 4.5 million cycles per year.
• Industry: Machine tools
• Success for the customer: Highly tensile energy supply with simple filling. Compact type for compact machine design with more space for the cable. High flexibility thanks to precisely manufactured ball and socket joint connection without steel cable. Long service life under the highest loads.

Manufacturers of complex turned parts want to complete as many machining operations as possible in a single clamping operation, as this saves time and money. This goal can be realised in the best possible way with the SCX-series from Schütte (Fig. 1). Even in the basic version, the multi-spindle automatic lathes offer six main spindles and a counter spindle for workpieces that can be produced almost entirely from the first side of the workpiece. For applications where the second side of the workpiece also needs to be machined extensively, the concept can be expanded to up to nine spindles (Fig. 2). And since the spindle can also work in the C-axis and Y-axis, the user of an SCX automatic lathe has completely new freedom when machining complex workpieces. One of the fundamental design features of the SCX series is the fact that the developers have banished everything from the work area that is not directly involved in the creation of the workpiece: drive and guide elements, lubrication and cooling lines as well as electrical cables. Nevertheless, every spindle must of course be supplied with coolant, hydraulic oil, energy and signals. And high demands are placed on this media, energy and signal supply: In addition to the axial feed, a very fast rotary movement must also be carried out. The application places extreme demands on the service life of the energy chain: typical cycle times of 5 to 10 seconds result in 5760 cycles - and correspondingly many movements of the energy chain. This means that the first 100,000 cycles are reached after just 17.3 shifts. Extrapolated to a year in 24-hour/5-day operation, this amounts to more than 4.5 million cycles per year. And Schütte is by no means satisfied with one year of service life for a component: The machines are known worldwide for their long service life.

An energy chain was planned from the outset for the energy supply to the spindle. However, the model originally selected did not fulfil Schütte's high demands. During the production of the first series, the staff gave the design manager the feedback that the energy chains were difficult to fill.
As a result, the company looked around for an alternative. This was found in our multi-axis energy chain triflex® R (Figures 3 and 4), which was originally developed for demanding six-axis robot applications in harsh industrial environments, i.e. for axial and rotary movements in one chain.
Despite its high tensile strength, the three-part 3D chain is very easy to fill - right down to the last centimetre. Even the media lines, e.g. for the cooling lubricant, which have a fairly large cross section, could be clipped into the chain by the customer without much effort.
Schütte's production staff were therefore quickly won over by the new e-chain®. And the designers appreciate the compact type, which is important given the limited space available in the machine. The triflex® R offers more space for cables than the previously used model, and as it does not require a steel cable thanks to the precisely manufactured ball and socket joint connection, it is also extremely flexible.
The energy chain is designed from the ground up for a very long service life, even under the highest loads. This has been demonstrated both in tests and in practical applications: The energy chain can withstand the high load trade show - even though it has to cover large distances at high speed with every cycle of the mould and perform sweeping stroke and swivel movements. Even the oil mist from the often aggressive cooling lubricants does not impair the service life of the chain.
The SCX-series specifically uses the triflex® R-Type TRL 60, where the L stands for "light" and the number indicates the inner diameter of 60 mm. The closed design of the basic version triflex® R could be dispensed with because the drive chamber remains chip-free.