A new machine dimension for a valued customer

Henning Albrechtsen, owner of the Danish family-owned company HACO A/S, had been looking forward to receiving a Droop+Rein portal milling machine from Starrag, and he was not disappointed when the machine landed in November 2023. The special features of this 870-ton colossus include its XXL size and its unusually large basement section across two storeys.

“Never before have we built such an extensive tunnel system for a production plant; it is reminiscent of ancient catacombs and even I have never seen something like this anywhere else,” explains Hubert Erz, Senior Consultant Sales/Renewables at Starrag. “However, this expensive and elaborate investment for our core customer facilitates service access and day-to-day collaboration using this new machine.”

Laying the foundation involved processing 850 cubic metres of concrete and 100 tons of steel, the machine provides operators with easy access to drive elements and other components of the Droop+Rein portal machine. In any case, the basement section immediately garnered a positive response from the production team. As Henning Albrechtsen states: “The foundation forms the base for the machine tool, and its stability and design help determine the level of precision that can be achieved with the machine. In addition, the tunnel system within the foundation provides good access to all relevant machine assemblies and thereby ensures optimal ease of servicing.”

The company already owns five Dörries vertical turning lathes, which have helped it grow to become one of the leading Danish manufacturers of gigantic components for the wind power sector and offshore industry.

Danish teamwork: XXL rotor housing for the future of wind power

As a job shop specialising in XXL components, HACO cannot afford downtimes. As such, HACO has already needed to increase the maximum swing diameter of its vertical turning and boring mills several times. Their next major order, from an international leader in the area of wind turbine manufacturing, involves completely new dimensions. This order focuses on the next generation of offshore turbines with rotor diameters that now exceed 660ft (220m), designed for an output of 14 megawatts with their direct drives. HACO and a Danish partner have been contracted to produce components of correspondingly large size. This involves machining front and stator sheets and brake discs, alongside other primarily welded components and multiple steel rotor housings with weights of between 50 and 90 tons and diameters of almost eleven metres.

To approach this challenge with confidence, Henning Albrechtsen decided to purchase a pair of machines designed to handle these ever-increasing dimensions. The first machine, a gantry portal milling machine with a 100kW milling head and 2×82 ft/lbs (111kW) master-slave main drives, represents the combination of two distinct areas of expertise for Starrag. As Hubert Erz from Starrag continues: “We integrated components from the Dörries product area into a Droop+Rein milling machine, thereby combining turning technology with milling technology.”

The machine has a clearance of 12.6m in between the stands, the gantry axis travels over a distance of 14m, and the tool slide allows a maximum stroke of 3.5m.

Complete machining improves  productivity 

Assembly and commissioning were performed by a Starrag team led by Fabian Schwarz, Head of Project Management of the Business Unit Large Parts Machining Systems (LPMS) with the product areas of Droop+Rein, Dörries and Berthiez. Even though large machines are part of his day-to-day work, this new creation with its hydrostatic bearings and rotary table with a weight of 180 tons and a maximum load capacity of 350 tons is still something quite special. One benefit of the machine is that it combines milling and turning in a single machining centre. “Integration of both processes enables the production of complex workpieces with great precision and efficiency. This saves users time and money, as they need fewer machines and undergo reduced setup times,” Schwarz explains.

The table of the second machine is movable. The machine delivered at the end of 2023 features a moving portal, whereas this configuration has a stationary portal and a moving table. As Hubert Erz adds: “This special design, created primarily for turning processes has received new support with the new tool holder constructed and constructed by the Bielefeld team for combined milling/turning operations.”

In terms of dimensions and weight, the 6-axis portal turning machine is number one, and only the master-slave main drive (output: 2 × 36 kW) is somewhat larger. The plant has also gained a larger workpiece swing diameter, which was able to be increased from 13m to 15m thanks to the moving table.

Regardless of this, HACO can completely machine all workpieces on both machines, meaning that they can be used as ideal supplements or replacements for one another. This pair of machines also features highly precise positioning across all axes. The two machines can achieve electronically controlled positioning in the micron range even for metre-long travel paths.

Johan, the 87-year-old father of HACO CEO Henning Albrechtsen said: “When we established HACO, we invested in high-quality machines with automation right from the start. The first vertical milling machine was already equipped with an automatic pallet changer. This was later followed by a flexible manufacturing system with two linked vertical milling machines. Something like that had never been seen before in our region. As such, we are continuing to follow this innovative and future-oriented approach and developing to meet the challenges of the times.” This machine is still in Bielefeld and will begin its journey to Denmark in the first quarter of 2024.