Power and bus signals in a moving cable - play it safe!

• What was needed: chainflex® hybrid cables, energy chain
• Requirements: cables must be extremely flexible and guarantee a high service life and reliability with a very small bend radius
• Industry: machine tool construction
• Success for the customer: customised test programme for new cables that were specially designed to meet the customer's requirements and, in particular, can manage the particularly small bend radius

60 metres per minute: This speed sets the pace for the drilling stations that are integrated into the systems of IMA Klessmann GmbH. They have to drill holes at high speed, even if the components are produced on commission and have different drilling patterns. IMA Klessmann's "Drilling Technology" business unit has developed the flexible IMAGIC flex drilling system for this application profile. The individually controllable drilling spindles enable horizontal and vertical drilling as well as dowelling and promise minimum set-up times even with complex drilling patterns - and at an impressively high speed. The customised systems are equipped with up to 50 axes, which have to be positioned and coordinated every second. In order to prepare the IMAGIC flex for this task, the design engineers also had to "upgrade" the drive and control technology accordingly and decided to use the latest servo technology. The new single-cable technology combines the power and feedback system in the servo cable. The single-cable technology saves material as well as costs and installation effort, as up to four kilometres of cable are laid depending on the position of the control cabinet - which is specified by the customer. At the same time, however, this presented the challenge that a hybrid cable was required that could guarantee a high service life and reliability at the same time given the high dynamics. Another complicating factor was the very small bend radius, as leading control technology companies had rejected the single-cable concept in the past. IMA took these concerns very seriously, especially as the mobility of the hybrid cables was an additional factor.

And the first enquiry to igus® was far from allaying any concerns. There was no guaranteed service life for the parameters under which the cables were to be used.
The reason for this was the small bend radius of the cables in the servo axes, which in some cases is up to 50 percent less than the nominal value specified in the catalogue. However, igus® suggested a customised test programme to IMA Klessmann. The hybrid cables were tested and inspected according to the drive manufacturer's specifications and the Hyperface DSL bus element with over 4 million strokes in the IMA-specific bend radius. They were then handed over to IMA for practical testing. After successful tests and application trade show, nothing stood in the way of the series launch.
IMA finally decided in favour of the PVCversion of the chainflex® hybrid cable. The majority of machine manufacturers use cables with PURjackets, particularly for high-speed applications. However, IMA has already had good experiences with PVC in the past. The company also uses PVC-jacket for other cables. They are less abrasive and very durable and fail-safe, even in highly dynamic applications.
For the guidance of the cables, IMA Klessmann also utilises the igus® range and uses ready-to-install "readychain®" systems. Open energy chains are used in which wood dust cannot collect. This means that customers can rely on safe systems from a single source, where the components have been optimally harmonised with each other through decades of development in the igus® test laboratory.