20.500.12556/RUL-143838 Advances in understanding of damage formation during laser-assisted milling of ZnO-based varistor ceramics Zinc oxide (ZnO)-based varistor ceramic is a hard-to-machine material. Its microstructure, developed for its electrical properties, results in extremely low fracture toughness. Therefore, the current state-of-the-art in machining this material is lapping. In the present work, laser-assisted milling (LAMill) of ZnO ceramics was evaluated with a systematic approach to allow for new insights and advance the understanding of damage formation during machining of this material. A machining strategy to machine ceramic workpieces along the edge was studied. Additionally, a new transient analytical thermal model was developed to accurately predict laser-induced temperatures near the edge of the workpiece without excessive use of computational power, and the model predictions were experimentally verified. A novel approach to evidence machining-induced damage with the mathematical description of the ideal machined surface was also designed and tested. It was found that at higher temperatures the propagation of intergranular fractures is inhibited. Another mechanism based on the material porosity and contributing to more instances of intergranular crack initiation has been identified. To reliably predict the extent of damage on the machined surface, the analysis has been extended by covering the effects of the two identified influential process parameters: feed per tooth, f$_z$, and the temperature of the to-be-cut material, T. By adjusting these parameters, surface damage was successfully controlled and the extent of damage was minimized at f$_z$ = 0.18 mm and T = 380 °C, achieving a 44 % reduction compared to the conventional process with the same machining parameters. laser-assisted milling ZnO ceramics thermal model damage formation lasersko rezkanje ZnO keramika toplotni modeli nastanek poškodb true false true Angleški jezik Slovenski jezik Članek v reviji 2023-01-13 11:43:02 2023-01-13 11:43:08 2023-01-15 04:01:29 0000-00-00 00:00:00 2022 0 0 Str. 1478-1491 Vol. 84 Dec. 2022 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 621.7 1526-6125 10.1016/j.jmapro.2022.11.008 130224387 1-s2.0-S1526612522007812-main.pdf 1-s2.0-S1526612522007812-main.pdf 1 8733E79E6E376F79E36D39F213E84AF7 225359ad93af5feb0fed0a6212442b565c24426316373683e0b97e289ac557d5 0bbe99d3-932f-11ed-9c94-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=165850 https://www.sciencedirect.com/science/article/pii/S1526612522007812 1 d59fdf75-932e-11ed-9c94-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=165849 Fakulteta za strojništvo 0 0 0