چكيده به لاتين
Abstract
Due to the ever increasing expansion of the knowledge, using of machining modern methods for solid and stable materials like Titanium alloy, super alloys and ceramics is increasing. Standard machining of these materials creates high shear forces. Laser beam machining provides a suitable solution which has a direct correlation with material properties like heat conductivity, specific heat and also boiling and melting points. In this research, while introducing the parameters of fiber laser cutting, we study the effective factors for optimization procces in order to avoid the negative effects of the cutting zone including non-standard geometry, expansion of the heat affected zone and the cracks resulted from rise of temperature. Laser power, cutting speed, assisting gas (Nitrogen) pressure and the nozzle distance from the workpiece surface were studied on two quantitative answers of the heat affected zone and the cutting edge profile (amount of tapering) and one qualitative answer of spatter amount. This experimental work was performed using Response Surface Methodology in the Design Expert software with Central Composite Design method and on stainless steel 316L and data were analyzed by Analysis of Variance. Results show that in average amount of laser power and nozzle distance from the workpiece surface and high amounts of cutting speed and assisting gas pressure, a smaller heat affected zone is created up to 35% reduction compared to the maximum amount. If laser power is increased and the nozzle is closer to the workpiece surface, the heat affected zone and the difference between entrance and exit diameters will increase. Spatter in lower amounts of cutting speed and assistant gas pressure will increase with the rise of laser power.
Keywords: Laser Beam Machining (LBM), Fiber Laser, Cutting Edge Profile, Heat Affected Zone (HAZ), Spatter, Response Surface Methodology (RSM), Stainless Steel, Analysis of Variance (ANOVA)
