LINSINGER know-how ensures stability during heavy winds

Heavy plates for offshore wind towers have to withstand enormous forces. Therefore, leading manufacturers of wind tower steel foundations rely on milling technology from LINSINGER.

The use of wind power off the coasts (offshore wind farms) is booming: despite COVID disruptions, 2020 was the second highest year for offshore wind installations – worldwide 6.1 GW of offshore wind was installed. This trend will certainly continue. Forecasts for the next decade predict 235 GW of new offshore wind installations under the current policies.

Even more than on land, such wind towers at sea place the highest demands on materials and technology. This applies above all to the steels and heavy plates used. Our customers are among the most important suppliers of edge-milled plates for wind turbine manufacturers. They rely on sheet metal plate milling machines from LINSINGER.

Dillinger & LINSINGER – a perfect match

The longstanding client Dillinger is the market leader in the manufacturing of high-grade heavy plate steel for the offshore wind industry. The Dillinger group acquired the first PFM machine in 2003, which proves their foresight for the wind industry. To keep up with the world demand and to stay number one in this field, Dillinger just acquired another plate edge milling machine from LINSINGER. This brings it to a total of four machines for the Dillinger group – three in Germany and one in France.

The Dillinger Group employs a total of around 6.200 people. High-tech plate from Dillinger is used to realize extraordinary and technically advanced projects all over the globe in the offshore wind power sectors furthermore steel construction, mechanical engineering, offshore, and line pipe and boiler construction sectors, as well as and many others.

Copyright: Uwe Braun, SHS – Stahl-Holding-Saar

Highly versatile plate production

The LINSINGER plate edge milling machine at Dillinger is the largest plate edge milling machine of its type in the world. This machine mills plates up to a thickness of 180 mm, length from 4 m up to 30 m and width from 1.35 m up to 5 m width, with weight up to 45 tons. For an 80 mm thick plate the four machines can mill 384 m of edge per hour and each of them has 2 x 142 kW milling power. The single machine weighs up to 400 tons and is about 110 m long. For easier handling, it also automatically removes the chips during the production.

In addition to rectangular plates, LINSINGER plate edge milling machines can mill the edge profiles on trapezoidal and tapered plates as well. These are required for the tapered geometry of wind tower structures. Plate edges for plate thickness reductions (taper edges) can also be milled. The plates are pulled through the 2 cutting stations on each side of the machine. The cutter heads are equipped with special carbide tips which prevent any thermal impact. The machine is designed for short processing times and efficient plate handling from start to finish.

Typ PFM LLqq

The Falcon – 4-sided plate edge milling machine

For the next step of the manufacturing process of a wind tower, LINSINGER’s latest generation of PFM PT plate edge milling machines enables edge processing on all four sides (two longitudinal + two transverse sides) of a plate in one clamping. The proven “LINSINGER Thick Chip Milling Technology” ensures a high feed rate at the lowest possible tool costs.

The machine can be customised 100 % and sheets of any size with a weight of up to 200 tons can be processed. The gantry milling concept and magnetic clamping units provide maximum flexibility and complex sheet shapes such as trapezoidal and curved sheets (e.g. for the shipbuilding and wind tower industries) can also be machined. This state-of-the-art machine is able to mill tapers too. Special clamping tables are available for non-magnetic and complex materials such as stainless steel, high-alloy steels, duplex and super-duplex alloys. Optional minimum quantity lubricant spray nozzles ensure economical machining of these materials as well.

Achieving success with economy and maximum precision

Depending on the required productivity, the four edges can be machined with one or two milling units. The two long sides are machined simultaneously, which decisively increases the throughput and thus the cost-effectiveness of the system (maximum milling speed: 10 m per minute). The sheet is quickly and easily aligned by means of a coordinate matrix developed by LINSINGER and fixed in place by pre-positioned magnets. High-precision drive technology, a CNC control system, and the machine program, which was also developed in-house by LINSINGER, are further factors that guarantee the highest precision on the workpiece and the lowest plate tolerances.

At the same time, all LINSINGER plate milling machines allow the use of special milling heads, which can be designed in sandwich construction and allow maximum flexibility in the weld profile shapes. Options such as automatic tool changing devices, automatic loading and unloading systems further round out the level of automation. This makes production economical even for small batch sizes, even for a single piece if necessary.

LINSINGER tool technology – tool and machine from a single source

20 years ago, LINSINGER took a bold step. The manufacturer of special machines and equipment for the steel industry created an in-house tool technology center.

In today’s production industry, machine costs are calculated in life cycles (life cycle costs). The company found the running costs for tools, calculated over the life of the machine, amount to a multiple of the investment price of the machine.

The machine know-how and the specially tailored tools enable LINSINGER to provide the customer with a reliable view of the tool costs already in the project planning. When commissioned in-house, this package is further refined and precisely tailored to customer requirements. This eliminates the need for lengthy tests after commissioning at the customer. Production runs, in the shortest time, with the agreed output.

Should there be a need for further optimisation at a later point in time, there is no need for lengthy third-party discussions where the customer could suffer, the partnership with LINSINGER provides the optimum solution. LINSINGER, working as sole supplier, is solution-oriented and offers comprehensive after-sales support via our service technicians and tool specialists worldwide.

A trendsetter with humble beginnings

In its over 80-year-old history, the company grew from a small family business to a global player with over 500 employees at its company site in Austria.

But let’s not forget its humble beginnings in 1938. Dr. Linsinger started his business with small milling machines which were made by a handful of employees. The strategy to focus on niche products proved right. Throughout its company history new machines and techniques were developed such as a patent on high-speed milling or the invention of mobile rail milling. Beginning of this year the largest circular saw in the world was completed and in 2020 the world’s first hydrogen powered rail milling train was presented. The secret to success does not only lie in inventions and new products, but also in the service their customers receive. Therefore, the opening of a branch in China in 2021 was a necessary step to be closer to our customers in Asia – solely to offer the best and fastest service possible.

With the plate milling machines from Upper Austria, plate suppliers are perfectly equipped for the strong upswing in the offshore wind farm market, which will continue in the coming years. In addition, the wide PFM type range also offers the perfect solution for any other customer requirement.

Note: The opinions, beliefs, and viewpoints expressed in this article do not necessarily reflect the opinions of Offshore WIND.