Machining Large Components for Wind Turbines

“As yet the wind is an untamed, unharnessed force, and quite possibly one of the greatest discoveries hereafter to be made will be the taming and harnessing of it.”
Abraham Lincoln, 1858

Eight score and two years later, Abraham Lincoln’s prophesy has become reality. Harnessing the wind has become an important source for energy. Wind energy generated 7.2 percent of electricity in the United States in 2019 and supports more than 120,000 jobs.

The 280-foot tall wind turbines dot rural landscapes and appear like soldiers guarding the entrance to their domains. The three blades, each measuring 120 feet in length, move slowly, allowing the turbine to rotate smoothly into the wind. Machines with a similarly impressive scale are required to produce these giants. There are some of Starrag’s product ranges including Heckert with its Large Athletic Series, Berthiez RVU vertical grinding machines and Dörries vertical lathes. These machining centers are ideal for particularly large, heavy workpieces and have proven useful for wind turbine manufacturers around the globe.

For example, Heckert HEC 1600 machines can process workpieces with edge lengths of 11 feet and up to 13 tons in weight. Dörries lathes combine excellent productivity and maximum precision. These vertical lathes have been developed for tailored solutions of planetary gear carriers in wind power plants with their extreme demands in terms of accuracy. Berthiez RVU 2800/250 machining centers are suitable for grinding, turning, drilling, cutting and performing inline measurements on large components in a single clamping operation.

Starrag, with its machining centers have created many sophisticated workpieces, with varying sizes, weights and technological requirements that are required in the production of wind turbines.

Starrag’s future in wind energy machining looks bright. According to the US Department of Energy’s Wind Vision Report, the industry supports a strong domestic supply chain with the potential to create 600,000 jobs in manufacturing, installation, maintenance and supporting services by 2050. The same report shows that wind can be a viable source of renewable electricity in all 50 states by 2050.

The Heckert ultra-stable cross bed construction and its thermos symmetric design allows high-precision machining with a short turnaround time. It also can minimize off-peak times with several set-up spaces. The technological challenges in the production of wind turbines include the large, complex gearboxes, which house deep-lying form elements. The Heckert HEC 1600 has an NC quill with stepless adjustment up to 30 inches for long travels and the machining of deep-lying form elements. The NC quill guides the tool into the gearbox houses to work safely without requiring expensive special tools with excessive lengths.

Modular design and flexibility are characteristics of the Heckert HEC 1600. It is possible, for example, to choose between a horizontal main spindle optional with integrated extendable NC quill, or a swiveling horizontal/vertical head for 5-sided machining. This enables the machining center to be matched ideally to customer requirements.

The NC quill adds to the versatility of the Heckert HEC 1600. It provides a significant surge in machining large gearbox housings, torque support and planetary gear carriers in large components for many sectors, including the power generation industry. Their accuracy is the result of automatic temperature compensation for thermal influences and thermal stability by cooling the quill and its bearing with a separate cooling unit.

The Dörries CONTUMAT VCE 1600 and VCE 2800 turning lathes are designed to process diameters of up to 63 inches and 110 inches respectively. VCE indicates the single column design of the compact lathes, which have a vibration-reducing cast iron construction. The symmetrical transmission and frame design ensure even temperature distribution – the basis for the unparalleled accuracy. Speeds of 450 and 224 RPM and hydrostatic guides in the X and Z axes also make a major contribution to the overall productivity.

Features and Benefits

Wind turbine manufacturers benefit from numerous Starrag machine product features. For example, manufacturing time can be reduced by 50%, set up times are reduced because clamping, unclamping and re-clamping parts are parallel to the machining and non-productive idle times are saved with high dynamics in tool and workpiece handling.

Also, the highly reliable machines guaranty highest production safety and workpiece quality

This is all possible because Starrag machines incorporate premium machine features including:

• Ready-for-assembly complete machining of transmission casings in closed and split designs
• High-speed, vibration-free machining of deep-lying drill holes by using an extendable work spindle
• Optimum process stability due to comprehensive control and monitoring devices within the system
• Fully automatic complete machining on only two clamping positions
• High storage capacity for tools, automatic loading and unloading of oversized tools
• High, long-term workpiece accuracy and optimum workspace conditions with improved traverse end positions of the work spindle – 9 in (225 mm) before pallet center
• The Heckert HEC 1600 is equipped with two pallets, allowing clamping, re-clamping and unclamping parts are parallel to the machining.

Starrag machining centers have supported manufacturers of wind energy turbines around the globe, which produced 64 GW of electrical energy in 2019. The United States, along with China, remain the world’s largest onshore wind energy markets and accounted for 60% of new wind capacity in 2019, according to the Global Wind Energy Council.

About Starrag

Starrag Group is a global technology leader in manufacturing high-precision machine tools for milling, turning, boring and grinding workpieces of metallic, composite and ceramic materials. Principle customers are internationally active companies in the Aerospace, Energy, Transportation and Industrial sectors (Industrial Components, Luxury Goods, Med Tech). In addition to its portfolio of machine tools, Starrag Group provides integrated technology and maintenance services that significantly enhance customer quality and productivity. The umbrella brand Starrag unites the product ranges Berthiez, Bumotec, Dörries, Droop+Rein, Ecospeed, Heckert, Scharmann, SIP, Starrag, TTL and WMW. Headquartered in Rorschach/Switzerland, the Starrag Group operates manufacturing plants in Switzerland, Germany, France, the UK and India and has established a network of sales and services subsidiaries in the most important customer countries. The shares of Starrag Group Holding AG are listed on the SIX Swiss Exchange.