Laser remote cutting and surface treatment in manufacturing electrical machines—High productivity, flexibility, and perfect magnetic performance

Abstract

From industrial electrical machine production, it is well known that processing of nonoriented electrical steels causes changes in the lattice and microstructure that also affect the magnetic structure. While applying these manufacturing techniques (punching or laser fusion cutting), mechanical and thermal stresses are induced due to elastic and plastic deformation or temperature gradients within the material. For more than 15 years, fusion cutting with CO2-lasers enabled a flexible and wear-free production but mostly for prototypes and small batches. Ten years ago, the development of diffraction limited solid-state lasers started and thus enabled laser remote cutting (LRC). Nowadays, industry demands sheet thicknesses between 0.35 and 0.5 mm due to the fact of eddy current loss reduction. Concerning this context, best choice is LRC. Within this work, latest results are presented in terms of resulting cutting speed, cutting edge quality, and magnetic properties. Cutting speed of LRC beats laser fusion cutting keeping the high rate of flexibility. The magnetic material properties of laser remote cut laminates are identical or even better to conventional punched parts. Therefore, the manufacturer has been given the possibility to tweak his process toward perfect magnetic behavior or high output volume. All in all, it will be possible to produce high efficient electrical machines regarding the application demands of the costumer.