Here’s how one company addressed the challenges of wind tower manufacturing. Article by Stefano Santoni, DAVI Promau.
MAM Maschinen, part of the ENERCON Group, processes more than 33,000 tons of steel per year. Employing around 300 people, MAM Maschinen is currently one of the most relevant players for the fabrication of heavy-duty components for several industrial sectors, in particular, wind towers and steel bridges.
In line with the trend towards higher efficiency in manufacturing, MAM has been improving its degree of automation as well as internal know-how to provide the highest quality products to their customers with the maximum respect for the environment.
In this framework, MAM Maschinen became in need of a plate roll technology partner that could support their serial and intensive production of wind tower sections. Evaluating different plate roll manufacturers, the company aimed at identifying the optimum technology in terms of performance, repeatability, and reliability to comply with the strict tolerances imposed by the end-users.
“From the initial contact in 2017 to the final purchase, dealing with DAVI has been satisfying in every respect,” says Andreas Kühn, Innovation Leader at MAM Maschinen. “The negotiation with the company was fair and they managed to meet our requirements. Now, we are happy with the machine that is working properly and quick. We are carrying on the foreseen works on our DAVI plate roll that entered our production flow, making it smoother and with no issues caused.”
MAM Maschinen selected a four-roll plate rolling machine with a capacity of 3,000 x 96 mm, equipped with dedicated accessories for the highest level of flexibility. The DAVI machine now constitutes a major fabrication asset to MAM, being utilized to roll wind tower sections as well as other components for the mechanical industry, in general.
Leveraging 50 Years of Experience and Know how
With over 50 years of experience in delivering high quality three- and four-roll rolling machines, DAVI’s R&D developed high-value patents deployed in unique product lines specifically designed for the wind energy industry. DAVI also developed a proprietary Wind Energy control system capable of providing full automation as required by the Industry 4.0 standards.
DAVI’s High Productivity Line introduced to the market innovative CNC-controlled features such as the possibility of executing exacts first pre-bending at the beginning of the rolling process, thanks to the patented infeed lifting conveyor. By lifting together with the bending rolls, the conveyor supports the plate while pre-bending, completely eliminating the distortions which would otherwise occur due to counter bending forces generated by the plate own weight.
While rolling large diameter workpieces, the front edge would “close” under its own weight and adjustment operations would be needed in order to avoid overlapping with the trailing edge. As part of the High Productivity Line, DAVI’s patented pushers with hooking fingers installed on the lateral supports completely eliminate the risk of overlapping as well as allow for perfect positioning and alignment of the two plate edges at the end of the rolling process in preparation for on-machine tack welding. The two features combined can increase the operation speed by 25%/30% (compared to manual process).
Addressing the Cone Forming Challenge
Cone forming is recognized as the most challenging rolling process. Forcing the plate edges to travel at two different speeds, the process generates high stress on the rolling machine as well as on the plate itself. On a typical wind cone application, it is of paramount importance to protect the integrity of the bevels, which must be realized prior the rolling process (due to high costs involved in beveling the plate after it is formed into a cone or can). For this reason, the state-of-the-art Wind Towers & Foundations cone rolling involves a step-by-step forming process where, at each step, the plate must be repositioned in order to make sure that the cone generatrix overlaps the top roll axis. Depending on accessories installed, this repositioning would both take a very long time, deplete the final workpiece tolerances and potentially put the operators at risk
DAVI responded to the industry needs by introducing a ground-breaking fully automated cone forming system. This is achieved by positioning and guiding the plate while cone forming without damaging the bevels (wide contact surface) for plates up to 100mm. This system allows for a complete cone forming executed by a single operator, with maximum repeatability, highest accuracy and the shortest possible floor-to-floor time (30 percent–50 percent faster compared to manual process).
The whole process—consisting of plate positioning, squaring, pre-bending, rolling and aligning for tack-welding—can be completed in less than 20 minutes, even for high-thickness plates.
“The positive experience we are having with DAVI leads me to believe that, for future needs, we will certainly make contact with them again. The plate roll shows a high quality and an impressive mechanical stability. A relevant aspect we really appreciated about DAVI was the customer support we can receive in our own language, that made the troubleshooting easier and faster. The aftersales care we received from DAVI is really appreciated,” says Kühn.
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