The erosive mechanisms and machining performance in abrasive waterjet cutting of iron-based amorphous alloy-resin laminations

Iron-based amorphous alloy laminations possess outstanding magnetic properties, but are extremely difficult to machine into the required core cavities for high energy efficiency electrical machines. Abrasive waterjet (AWJ) machining is expected to realize the efficient machining of laminated iron-based amorphous alloys with good performance due to its cold and flexible machining characteristics. In this study, the cutting performance and microscopic material removal mechanisms in AWJ machining of iron-based amorphous alloy laminations are investigated. It is shown that good kerf quality without process-induced crystallization can be produced efficiently, while the jet impact triggers a minor push-out delamination at the bottom of through kerfs. The material removal is dominated by brittle fracture in the initial damage zone, while plastic deformation induces the contact of interlayer metal strips in the smooth zone. By contrast, a combination of plastic deformation and viscous or brittle fracture in the striation zone where localized adiabatic temperatures rise induces viscous flow and associated viscous fracture within the amorphous alloy layers. Furthermore, predictive models for the depth of jet penetration are developed and shown to be able to adequately forecast the depth of cut with a mean deviation of 2.22% and a standard deviation of 11.15% from the corresponding experimental data. Finally, new techniques are proposed to minimize or eliminate the under-cuts and over-cuts on the lower part of the cutting front in non-linear traverse cutting and are shown to be effective.