Nickel-silicon-chromium-copper (C18000) alloy is widely used for many precision applications due to its high thermal conductivity, hardness, and moderate strength in fabrication of parts of molds. This study was carried out on this material for achieving mirror finish and minimizing profile error. Four machine and tool parameters were varied at different levels in a single point diamond turning operation to create a spherical profile on the workpiece. The surface roughness and profile accuracy were significantly affected by tool nose radius, feed rate, and spindle speed and depth of cut had insignificant effect. The process was optimized separately for both surface roughness and profile accuracy. Increased tool nose radius caused a ripple like effect on the machined surface as compared to a digging effect with low or no tool nose radius and thus showed a better surface finish. The profile error, however, increased with tool nose radius. Subsequently, both surface roughness and profile accuracy were optimized together using grey relational grade to obtain a globally optimized solution. The final parameter setting in an optimal solution identified feed rate as the most significant parameter followed by nose radius and spindle speed. A surface roughness and profile error of 15 nm and 0.464 mm, respectively, was attained during the confirmation experiments.
Multi-layer reflective thin film filters optimized for oblique incidence angles were deposited on glass substrates using Electron Beam evaporation technique with in situ thickness monitoring. The present study involves deposition and optical characterization of 5 layered multi-layer structures of TiO 2 -Al 2 O 3 and TiO 2 -SiO 2 having different thicknesses for varied wavelength ranges in the visible region. Three TiO 2 -SiO 2 multi-layer thin film filters were deposited having peak reflectance at 480 nm, 540 nm and 675 nm respectively corresponding to light sources in the blue, green and red wavelength regions. Similarly, a TiO 2 -Al 2 O 3 multi-layer was fabricated having peak reflectance of around 64% at 610nm. These filters were deposited at an elevated temperature of 250° C in an oxygenated reactive environment for better adhesion, mechanical strength and proper stoichiometry. Reflectance measurements of these multi-layer filters at oblique incidence angles reveal high reflectance of around 70 ~ 75% with a reasonably broad reflection band which can have wide applications in beam steering, shaping and folding applications in various complex optical systems facing constrained space and weight requirements.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.