Straightening machines work reliably with igus bearing technology, e-chains and cables

With the help of levelling machines for sheet metal processing, almost all stresses in the sheet metal that arise during forming or punching can be eliminated to ensure the quality of the products during further processing. Tribo-optimised plastic plain bearings help to solve the various technical challenges. Machine elements from igus have been used in the Kohler Maschinenbau product range for many years. "From plain bearings for linear technology to plastic rollers - we are finding more and more applications for the lubricant-free and corrosion-resistant components," reports Günter Keller.

"With our machines, the most important thing is maximum reliability," says design engineer Lothar Hug. "When the system is on site at the customer's premises, it has to run continuously without any problems." Three and four-shift operation seven days a week is the norm here. The environmental conditions that the plastic components have to withstand are extremely varied. "In a current project in the aviation industry, we are levelling sheet metal at -80°C. This means that we get a lot of condensation on the machine. Another example involves special alloys that can only be straightened after cooling down to 900°C," says the design engineer.

Added to this are a wide range of climatic conditions. At ambient temperatures of 40 to 45°C and a humidity of 95%, the machines must run just as reliably as at -20°C. However, scale particles and the omnipresent rolling and drawing oil place the highest demands on the machine elements. "The igus polymer bearings also prove themselves in these harsh environmental conditions," reports Günter Keller from his everyday work. "Their long service life, ease of maintenance and resistance to dirt have paid off right from the start."

Design engineer Lothar Hug can also confirm this: "As some of our systems are located in very confined spaces, maintenance and servicing are playing an increasingly important role for our customers, especially those in the automotive industry. As the polymer bearings are lubricant-free and also insensitive to dirt, possible maintenance intervals are reduced to an absolute minimum. Of course, we can score points with our customers with this!"

A system with an overall length of just 13.50 metres was recently designed for a car manufacturer. As it is located in a very confined space, ease of maintenance was one of the main customer requirements, which was achieved by using plastic plain bearings.

"Contamination of the side guide is often a particularly hot topic for us," says Günter Keller. Oil drips everywhere and the belt is sometimes damp. In this aggressive environment, for example, eight drylin R linear plain bearings with supported shafts serve as a guide system. They are based on highly wear-resistant polymers specially developed for linear technology. The dimensions are compatible with standard ball bushings. Their special geometry guarantees robustness, even in extreme environments. Added to this are the high loads. "We also demand a great deal of flexibility from our suppliers here.

The design effort required for the lateral guide is particularly high. Added to this is the high level of vertical integration. "For standard machines, we are intensifying our collaboration with igus. We receive the lateral guide as a complete system, which is then simply flanged on. This eliminates the design work, parts production and assembly for us. The technical and economic benefits are around 50 per cent," calculates Lothar Hug. "It pays off for us in every respect."

From the start to the end of the belt, there are a series of processing steps. Around 1,400 iglidur rollers are used as smooth-running transport rollers for the complete guidance. There are several technical advantages in favour of this. "The belt is partially coated and oiled. As the special plastic is insensitive, there is neither wear nor damage due to scratches or other quality losses. The surfaces are in perfect condition," summarises Günter Keller.

In addition, iglidur G plain bearings and igubal pillow block bearings are used for various adjustment tasks in the levelling system. They also prove themselves in their respective tasks and ensure safety and high functionality.

There are still a number of approaches to using polymer bearings in the levelling machines. The coil, for example, is first placed on the reel using an insertion aid. "This is where the highest loads occur, which place enormous demands on the technology," reports Lothar Hug. "Our ready-to-install rotary table bearings up to 15 tonnes are ideal for these points, for example," says Dominik Hartmann, technical sales consultant at igus. They are robust and can withstand the high loads without any problems." Initial discussions are already underway. Because "especially in special machine construction, we rely on the expertise of our suppliers in order to present our customers with the best solution," says Günter Keller.