Compact cable guidance for tight bend radii in a Trumpf bending machine

• What was needed: R4.1L series e-tube, chainflex®-cable
• Requirements: Supply of motor, encoder and sensor cables and earthing cables with minimum bend radius and high ease of assembly of the system, as compact a design as possible with a high number of cables to be routed at the same time
• Industry: Machine tool construction
• Success for the customer: short installation times and costs, easy maintenance despite closed system, minimum bend radius with high filling volume, particularly light energy supply system that requires little drive energy, no storage costs thanks to fast delivery from stock when ordering

TRUMPF is one of the world's largest machine tool manufacturers and has around 70 operating subsidiaries. TRUMPF Maschinen Austria was founded in 1992 in Pasching, Austria, the "competence centre for bending" within the TRUMPF Group. Today, the company manufactures bending machines in a wide range of sizes and designs here. The products represent both the highest level of experience and pioneering innovations in bending technology.
Among other things, the TruBend bending machines of the Series 5000 are built here in Pasching, of which more than 600 units are manufactured throughout the year. With this all-round machine, press forces of 50 to 320 tonnes and bending lengths of 1.25 to 4 metres are possible. The strengths of the system are particularly evident when it comes to large parts: when bending large or heavy parts, users of the TruBend Series 5000 are assisted by a bending aid on which the sheets to be processed are placed. This supports angles of up to 30 degrees and can be automatically adjusted in height. "This support is particularly necessary for large and very heavy workpieces so that the sheets can be bent accurately and by just one operator," explains Volkmar Schmidt, Head of Technical Purchasing at TRUMPF Maschinen Austria. The bending aid can be moved freely from left to right.
In order to guide the motor, encoder and sensor cables as well as an earthing cable safely along the machine, the machine tool manufacturer was looking for a suitable feed solution that was not only easy to install and minimised the bend radius of the cable. The solution also had to be able to carry a large number of cables and be as compact as possible.

TRUMPF now relies on energy chains from igus® to guide the motor, encoder and sensor cables as well as the earthing cable safely along the machine when the bending aid is moved. The machine tool manufacturer obtains the chains for the TruBend Series 5000 as Series R4.1L tubes - this means that instead of the crossbar used as standard, completely overlapping lids are installed. As with the open E4.1L version, the lid can still be opened on both sides and swivelled open by 115 degrees to prevent loss, which saves assembly time and costs. If required, they can also be completely removed, reinserted and closed by simply pressing them shut.
The e-tubes were originally developed to offer a chip-tight version of the e-chain®. In this specific application, however, TRUMPF wanted the closed version for purely visual reasons. In addition to ease of assembly and the minimum bend radius of the energy chain, another decisive point for the machine manufacturer is the maximum filling volume with the lowest possible external height. Compared to the E4.1 heavy-duty chain, the E4.1L and the otherwise identical e-tubes have saved so much mass that the chain is around 30 per cent lighter. This not only saves users a lot of drive energy. It also means that even more cable and hose can be accommodated in a given amount of space.
The patented positive-locking rear grip of the chain links and the double stop-dog with large stop surfaces have been adopted from the E4.1. These technical details ensure a high level of stability and also enable longer unsupported lengths. A 'brake' in the stop surfaces also minimises rolling noise, resulting in particularly smooth chain running.