Analysis of magnetic degradation and kerf surface for NO20 non-oriented electrical steel subjected to remote laser cutting

This article investigates process parameters for remote laser cutting of non-grain-oriented (NGO) silicon iron electrical steel (NO20), targeting a precise and clean lamination surface, acceptable overall cutting time, and low degradation of magnetic properties. NO20 is commonly used in rotating electrical machines. Remote laser cutting offers a higher design flexibility with respect to traditional cutting methods such as punching, resulting in higher design freedom. However, incorrect laser settings can result in a strong degradation of material magnetic properties as well as burned lamination surfaces and inaccurate cut profiles. Optimal laser power and scan speed settings are identified by microscopy of partial cuts and by surface inspections of fully cut sample strips. In addition, the magnetic characterization of sample strips is carried out to identify the optimum idle time (IT) between scans. Finally, the optimum parameter set for remote laser cutting investigated within this study is compared against guillotine and electrical discharge machining (EDM) methods, and found to compare favorably in terms of cut quality and impact on magnetic properties.