The machining of large components such as diesel engines, turbines, generators or ships' propellers means that machining centres are becoming bigger and bigger. This is also having an impact on machine tool technology itself. One builder of these complex machine relies on the latest generation of controls. A special overall solution with a measuring system cable that continuously transfers signals reliably over very large distances and ensures a high degree of machine availability has been developed for them.
The company Waldrich Coburg GmbH is one of the world's largest machine tool engineering companies. Highest quality standards and consistent customer orientation are the guiding principles of the machine manufacturer. Horizontal and vertical milling machines, vertical lathes and grinding machines are produced at the production site in Coburg.
The customers of Waldrich Coburg often use the machines for 20-30 years or longer, and availability of at least 95% is often required. For this reason, all the components have to work faultlessly for a very long time - whatever the circumstances. These circumstances mean a particularly high requirement profile for the cable guidance in the application.
Yet another complication is that the cables have to cope with the continuous movement in energy chains and the sometimes tough ambient conditions of metal machining without suffering any damage. Talking about this topic, Thomas Bischoff says: "Cables and connectors must be robust and satisfy the mechanical, electrical and chemical requirements. In addition, it must be easy to prepare them for use in our production facility without the need for additional special tools. Moreover, we wanted to use the familiar cable and connector material in order to avoid problems during the changeover.
Energy chains and chainflex cables from igus have been in use in large machining centres for many years. In smaller models of the gantry machining centres, the company uses pre-assembled energy supply systems that are sold under the name readychain. One reason for the decision: The manufacturer's customers like to use the machines for many years longer than expected and demand consistently high availability. "For this reason, all the components have to work faultlessly for a very long time - whatever the circumstances", says the Group Leader, summarising the requirements. "In this respect we have had very good experience over the years with chainflex cables from igus. "
In 2010 the large machining centre specialist decided to use new control technology in its machines, which also required new measuring system cables. Due to good experiences in the past, the choice fell on the chainflex cable CF113.028.D. CF113.D cables have a PUR jacket. They have an improved cable and shield structure for a longer service life in energy chains. In addition to the absence of halogens and their flame-retarding qualities, they satisfy other important criteria of the machine tool manufacturer, including certifications according to UL and NFPA79.2012.
In order to be able to present a solution, it is important that a cable functions correctly and that the number and nature of the individual connecting points are appropriate. "This cannot be a standard ready-to-use solution from the catalogue", explains igus product manager, Andreas Muckes. "We looked into the matter in great detail before we found the right answer. " In the igus test laboratory in Cologne, series of tests were set up in order to find the best connection solution. The cables were then sent to the user, who connected them to an original control system. Realistic machine loads were simulated in order to test the finalised cable concept for its suitability for everyday use.
All the efforts eventually led to the desired result. Today, the measuring system cables are showing what they can do in all machine centres with the new generation of control systems - even in cases where older machines have been retrofitted. They worked perfectly from the very beginning. A big advantage when it comes to assembly is that the popular M23 round connector can be used as standard components.
The results are convincing. The durability and the signal quality meet the requirements. A total length of 90 to 100 m is possible at the moment without any problems but 120 m is also conceivable“, says Thomas Bätz. In addition, there is a maximum of five connection points. "With this combination of connector and cable, we achieve extremely low attenuation. It is many times lower than in the case of the original of the control system manufacturer", adds Thomas Bischoff.
Servo motor feedback cables are always matched to the respective measuring system of each of the various suppliers. They must function correctly for a long time. "Our requirements regarding robustness and stability were fulfilled from the very beginning", points out Thomas Bischoff once again. "Close and fruitful collaboration in the development process allowed this. "
In its machining centers, Waldrich Coburg only uses chainflex cables that guarantee long machine operating times. They must also be available from stock. "Here as well, there were no problems of any kind", says Thomas Bätz in conclusion. "As shortages do not occur, fast reaction times are possible when necessary. “