Autor: Gert Goch

Wind energy becomes increasingly important, but the rapid evolution of wind turbines is at the expense of reliability. Insurance statistics revealed that the gear boxes often are the cause for malfunctions. Repairing is expensive and time consuming, as the delivery time for replacement gears and bearings can take up to 18 months. Thus, alternative solutions are requested, especially from the operating companies. Regarding gears, a manufacturing process would be interesting, which is independent from special and gear-individual tools like hobs. 5-axes-milling is considered to be a feasible approach for machining before heat treatment, as a variety of gears could be flexibly reproduced.

The article describes the quality inspection of micro cold formed components in the collaborative research center 747 “micro cold forming” at the University of Bremen. These components, e.g. small springs in cell phones, are manufactured with a speed of up to 300 parts per minute in a micro cold forming machine. Overall dimensions are below 1mm. These dimensions lie in a field between tactile measuring techniques of form and position and surface metrology, e.g. roughness. Yet a high inspection rate is impossible due to problems in production engineering and metrology. Therefore, fast optical metrology, new evaluation methods and quality control is needed to ensure an economical manufacturing process for micro cold formed parts.