Do you face the challenge of producing ever increasing size windmill blades, with tougher and tougher requirements for tolerances and quality? Increased requirements from customers for documentation and measurement reports? We are here to help you out. In the quest for renewable energy, wind turbines play an important role. Efficiently generating energy from the wind requires advanced aerodynamic shapes and highly accurate airfoils. In fact, even the smallest deviation in wind turbine blade profile can cost the operator dearly in terms of lost energy revenue.

GEOMETRY ASSURANCE: MINIMIZE SCRAP AND REWORK
One crucial requirement for building quality blades is the need to control the complete production process all the way from blade design, mold and plug development, layup of materials, molding and finishing, through to inspection of the finished blade surface.

Metronor has developed a series of products that are designed to assist in securing the geometry through all these process stages. Not only will a systematic approach to geometry assurance result in a high quality product for the end customer, but will also minimize scrap and necessary rework during the blade manufacturing process.

MOLD AND PLUG MEASUREMENTS
Metronor systems are ideally suited for geometry verification of plugs and molds. Online comparison can be carried out between actual shape and nominal shape as per the designed CAD model. Applications include both certification of plug and mold geometry, in addition to scheduled verification and maintenance checks.

The probing capability of the Metronor systems allow for a large number of measurement points to be captured in a short time. The real time geometry analysis gives the necessary correlation between blade and mold geometry to predict scheduled or “on event” mold maintenance needs.

BLADE ROOT MEASUREMENTS
The tolerances of the interface area towards the wind turbine hub (blade root) need to be controlled carefully in order to ensure both trouble free assembly and operation of a wind turbine. There are two critical characteristics of interest: Root flatness and Root hole-pattern geometry such as ovality and bolt hole center location.

BLADE GEOMETRY MEASUREMENTS
The efficiency and durability of a wind turbine is heavily dependent upon the shape of the outer blade surface. Typical characteristics to inspect include blade profile and thickness, trailing edge thickness, leading-to-trailing-edge length and the section twist relative the root hole pattern (“alpha angle”).

With Metronor systems, blade surface shape can be compared directly to the design CAD model in real time, or more simplified checks such as distances and thicknesses can be inspected without the need for CAD data.

ADVANTAGES
In today’s ever increasing strive for quality, geometry assurance of products plays an important role. The straightforward short-term benefit is the ability to deliver blades with certified traceable geometry to the end customer.

Longer-term benefits include the ability to study all parts of the production process in order to identify and correct weak points or bottlenecks. The ability to benchmark various production lines or factories is important in order to ensure blade geometries are identical, irrespective of production line or production factory.