Development of a Twin Disk Laboratory Metallography Machine

Abstract

Polishing is a vital step in metallography, which involves grinding and polishing metallic samples to prepare them for microscopic examination. A metallographic specimen polishing machine is a valuable piece of equipment in this process. The goal of this project is to design and fabricate an affordable and efficient polishing machine suitable for research centers, laboratories, and workshops in Nigerian higher institutions. The proposed machine uses motor-powered grinding wheels of appropriate composition, which rotate against a marked-out area of a metal sample to be polished. A chemically inactive liquid, such as Nita solution comprising nitric acid and ethanol, is used for etching. After polishing, the surface is flushed with water to ensure a smooth, polished surface that retains the original microstructural composition and arrangement inherent in the original sample. The polishing wheels are fine-grained, dense-structured abrasive materials bonded together with an appropriate bonding agent. The machine design incorporates the ability of the twin disk to run at different speeds. This machine can be used to etch various metals for proper surface exposure for optical or electron microscopic investigations and analysis, making it a valuable asset in metallography research.