The mechanism of surface evolution in the vibratory media finishing process is investigated through changes in surface profiles with process time. Using the profile of a masked portion of the surface as reference, changes in the surface profile mean line, peaks and valleys with time are examined. Peak heights are seen to reduce while surprisingly valley depths are also seen to diminish indicating evidence of plastic displacement of material from the peaks into the valleys. The surface evolution is thus shown to be a combination of material removal and plastic deformation of the peaks. This also partially explains the surface roughness saturation with time. © 2015 The Authors.

Sathyan Subbiah

Department of Mechanical Engineering

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IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Procedia Manufacturing

The polishing process is used to produce a smooth surface with a required geometrical figure for the optical component. The abrasive slurry jet polishing process is one of the non-traditional polishing process, which is used to polish freeform optics with the nano-level surface finish. In the abrasive slurry jet polishing process, the saturation in surface roughness is observed with a jet exposure time or polishing time. Once the saturation limit is reached a further reduction in surface roughness without the modification of processing conditions and the size of the abrasive particles is not possible. Hence to achieve the required surface roughness a different polishing strategy has to be adapted. In this work, an attempt was carried out to yield a considerable reduction in surface roughness using a multistage polishing concept. In this concept, the impact angle, the traverse speed of the nozzle, the type and size of the abrasive particle were changed after the first stage of polishing. The surface generation has been studied by measuring the surface roughness at each stage of polishing, and the Scanning Electron Microscope (SEM) analyses have been done to understand the changes in surface texture, after polishing. From the experiments, the large size Al 2 O 3 particle in the first stage of polishing and then small size Al 2 O 3 particle in the remaining stages of polishing yields a considerable reduction in surface roughness. The combination of parameters with the type and size of the abrasive particles to be used to achieve the required surface characteristics were demonstrated. Thus, the multistage polishing concept can be floated as a viable strategy to achieve a high reduction in surface roughness on the optical component. © 2019 Elsevier B.V.

Journal	Data powered by TypesetProcedia Manufacturing
Publisher	Data powered by TypesetElsevier B.V.
ISSN	23519789
Open Access	No