Case studies
Wind turbine rotor blade machining
A leading European manufacturer of wind turbines required the root end face of the composite rotor to be machined at 2.4m diameter. The rotor blade had a composite structure with both steel and GRP. The flatness tolerance was to be within 0.20mm at 2.4m and machining time within 1 hour. Mirage has now developed a system for production where no crane is required and it is fully portable. The system utilises a patented hydraulic chuck system to mount into the blade and then machines the root end face inserts flat. Current designs can cater for diameters up to 3.5m (61.5m blades) but with the ever expanding blade lengths we can adapt our orbital milling range to the new rotor blade designs, or client specific root end mounting diameters.
Location
UK, Denmark, India, USA
Equipment utilised
Mirage WP2500 with adapted base to mount on the 3 off moulded installation bolt holes within the blade GRP structure. A specifically developed power pack and trolley were also supplied to assist in providing the shortest floor – floor machining time possible
Method
The machine is bolted using the special base to the 3 mounting points allowing both the structure and machine to remain in its “free state” to get the best accuracy from the structure and machine possible. The high spots on the flange are then recorded and depth of cut set with the digital scale. The machine is fitted with a 125mm face mill and machining commences at 400 mm/min giving a rotation time of 20 mins. Floor to floor machining times of 30 minutes now possible and they have been in use since 2003.
