Thinking big, without compromising on precision

Miba Automation Systems occupies a special place within the Miba group of companies: The business is dedicated to special-purpose machine construction. Based in Upper Austria, Miba Automation Systems is a global player, in particular in the field of sustainable wind energy. For preparing the welding seams of offshore wind tower foundations, Miba Automation Systems relies on Boehlerit technology, with milling tools that guarantee maximum precision and tool life as well as top-level performance.

The roots of Miba Automation Systems go back to 1927 and the company first branched out into machine construction in the 1950s. At first, machines were built for in-house applications, in particular the manufacturing of slide bearings. In the 1980s, this field began to generate global interest, and the Upper Austrian business established itself as world market leader for machines in this segment. But that is just one aspect of its colourful history: Today, 70 employees at the Aurachkirchen site manufacture special-​purpose CNC machines for a wide range of industrial applications. Among the highlights are machines for e-mobility, used all over the world to produce stators for electric cars. Managing Director Ing. Klaus Weberndorfer, MBA: “Our core competence is the mobile and stationary machining of large workpieces.” Today, mobile and stationary machine tools by Miba Automation Systems are used primarily in the wind energy sector, in particular the manufacturing of offshore wind tower foundations. These foundations are fully immersed in water and consist of steel-tubular posts with diameters of up to 14 metres. To withstand the immense loads, the posts have to be rammed into the seabed to a depth of 50 metres and more. Due to their enormous dimensions, the posts consist of individual steel rings, which means that essential steps in the construction process must be completed on site, for instance the preparation of the welding seams and the welding process itself. “We have to take the machine to the component”, is how Klaus Weberndorfer sums it up. The same applies to the production of steam turbines for thermal power plants and the turbine casings used in hydropower plants, where components are also too large to be transported.

Ing. Klaus Weberndorfer, MBA, Managing Director Miba Automation Systems. (Image: Miba Automation Systems)

Perfect preparation of the welding seam

The solution for milling the huge wind tower foundations lies in using mobile machines for circumferential seams, and stationary machines for longitudinal seams. If you think that, with these sorts of dimensions, precision is probably not such a big deal, you’re wrong! “Our customers set great store by the flawless preparation of welding seams”, Klaus Weberndorfer explains. The individual tubular segments must be welded both longitudinally and circumferentially – a challenge, not least due to wall thicknesses of up to 150 mm. The Upper Austrian business has turned this niche into a success story. With its special machines for the milling of longitudinal and circumferential seams, Miba Automation Systems has established itself as market leader in recent years. The mobile machines are designed in such a way that they may be moved along the components by a forklift or on rails. Where the tubular segments meet, a tulip-shaped structure is milled into the future welding seam, which provides the seams with optimal stability despite the enormous loads they will be exposed to. At the same time, material usage during welding is minimised and the process is speeded up. Klaus Weberndorfer: “Usage of the welding material is a major cost driver, and we are able to offer our customers a highly economical solution.”

Longitudinal seam milling machines up to 12 meters workpiece length. (Image: Miba Automation Systems)

Miba Automation Systems is the partner for circular and longitudinal weld preparation for the construction of wind and hydroelectric power plants. (Image: Miba Automation Systems)

High performance, long tool life

The right milling tool is an essential element in this solution. Miba Automation Systems relies on the milling technology developed by Boehlerit, cutting and material specialist from Kapfenberg, Styria, and delivers its machines to customers all over the world with special Boehlerit milling tools. The diameter of these tubes is up to 14 m, with a material thickness of up to 150 mm. For the optimal preparation of the welding seam, it must be milled in several stages, down to a depth of up to two thirds of the material thickness. The lengths to be machined are therefore enormous – but constantly changing the tools would impact productivity, and ultimately also cost-effectiveness. Boehlerit offers distinct advantages in this context. Klaus Weberndorfer: “The indexable inserts are specially designed for the required geometries and offer maximum performance and tool life, even with materials that are difficult to machine.” In addition, high speeds are possible, an important factor for the customers of Miba Automation Systems. After all, even slight accelerations have a massive influence on the duration of the overall process, given the huge machining lengths. Boehlerit ticks all these boxes!

For the entire Wind Tower Production: Long seam milling machine. (Image: Miba Automation Systems)

The perfect system

In addition, Boehlerit offers its customers practical support with applications, which doesn’t end with cutting depths or speeds. Miba Automation Systems also benefits from this. At the moment, the company is for instance experimenting with milling tools for duplex steels, explains Weberndorfer. And there is another aspect that he insists on mentioning: “Ever since we started fitting our machines with Boehlerit milling tools, there hasn’t been a single complaint.” Not surprising, considering the expertise that Boehlerit brings to the table. Boehlerit is not content with standard solutions: This Kapfenberg-based business always strives for solutions that offer added value.

Miba offers the complete range of weld seam preparation machines. (Image: Miba Automation Systems)