فهرست مطالب حسن خسروآبادی

Micromilling is one of the main manufacturing processes of creating miniaturized parts which are highly demanded in many industries nowadays. Like any other machining processes, cutting fluids are used for cooling and lubricating during micromilling while it can be challenging due to small cutting zone. In this study, the effects of different cooling and lubricating systems such as dry cutting, wet condition and MQL systems are investigated on such characteristics as surface quality and wear of the micro tool. In case of the MQL, two methods of single-nozzle and bi-nozzle spraying systems are applied and their effects on such characteristics are compared to each other. Machining tests are carried out using a two-flute micro cutter with diameter of 0.8 mm on a titanium alloy Ti6Al4V. Results show that the MQL is significantly effective on the both cooling and lubricating whereas wet application has no effect on the cooling. Finally, using MQL applications results in lower tool wear and better surface finish compared to those of the dry and wet conditions hence the one with two-nozzle is more advantageous in micro end-milling of this alloy.

Micro end-milling is one of the main manufacturing processes of creating miniaturized parts which are increasingly demanded in many industries. Using tools with diameter less than 1 mm results in rising the so-called “size effect” and problems due to ploughing at low feeds per tooth. It is therefore crucial to estimate value of minimum chip thickness which helps to reduce or eliminate the ploughing. In this study role of scaling down is investigated with regard to milling operation in micro- and macro-scale. A titanium alloy Ti-6Al-4V is used as workpiece. Two-flute endmills with diameters of 0.8 and 2 mm are used representing micro and macro-scale, respectively. Effects of axial depth of cut and feed rate as input parameters were evaluated on such output characteristics as specific cutting energy, microhardness, surface roughness, topography and chip formation. Results show higher values of microhardness and specific cutting energy in micro-scale. Microhardness and specific cutting energy in micro-scale were found to be 6 times and 150% greater than the macro-scale, respectively. The study suggests that minimum chip thickness can be varied approximately between 0.25 and 0.49 of the cutting edge radius.