Search

This study focuses on systematically revealing how cutting parameters influence the surface integrity of ball-end hard milled surface of AISI D2 steel and proposing optimization scheme from surface integrity, wear resistance and fatigue resistance perspective based on response surface methodology respectively. Results can be summarized into three aspects. Firstly, radial depth of cut with percent contribution ratio (PCR) 62.05% has a decisive influence on surface roughness, followed by spindle speed 13.25% and feed per tooth 6.63%. The work hardening degree was raised from 12.5% to 38.4% when spindle speed changed from 8000 rpm to 2000 rpm. Spindle speed and radial depth of cut are the most significant factor influencing residual stress. The PCR of spindle speed and radial depth of cut reached 73.47% and 18.63% for residual stress in feed direction, 47.11% and 37.51% in step-over direction, respectively. High residual compressive stress can be generated by lowering spindle speed and radial depth of cut benefiting from the aggravated squeeze between ball-end milling cutter and workpiece. Secondly, too small feed per tooth or too small radial depth of cut should be avoided from wear resistance point because though the surface microhardness can be improved, the surface quality will also be deteriorated. The combination of high spindle speed, small feed per tooth together with small radial depth of cut can meet the wear resistance and the machining efficiency requirement. Finally, a medium-sized cutting parameter combination should be adopted to realize satisfying material removal rate and fatigue resistance. This study can be used to guide the selection of cutting parameters during ball-end milling of hardened AISI D2 steel for dies/molds manufacturing industries. [ABSTRACT FROM AUTHOR]

• Electron transfer velocity on milled surface were explained by plastic deformation. • Reversibility of electrochemical reaction was studied by cyclic voltammetry. • Electrochemical reaction products on milled surface of NiTi alloy were investigated. NiTi shape memory alloy is widely used in medical field because of its excellent properties. Milling machining has become one of the main processing methods in the medical field due to its good shape adaptability. However, the change of the shape and properties of milled surface affects its biocompatibility and corrosion resistance. Electrochemical machining is used as the follow-up process of milling machining. The polarization curve method, cyclic voltammetry method and constant potential electrolysis are used in this paper to study the electrochemical reaction mechanism of the NiTi alloy milled surface. The results show that the plastic deformation layer appears compared with the original material, making electrode reactions and electron transfer relatively difficult. The surface eventually forms TiO 2 , without the formation of Ni-related oxide. The electrochemical reaction mechanism of the NiTi alloy milled surface in the HClO 4 -CH 3 COOH system provide important theoretical guidance for the production and manufacturing of medical products. [ABSTRACT FROM AUTHOR]