Abstract

The polishing machine is one of the most useful pieces of metallography equipment for the grinding and polishing of metallic materials, particularly, surfaces of specimens. This is required in order to produce a flat, smooth and mirror-like surface before determine their physical structure using microscopy. This paper reports the design and construction of a variable speed abrasive polishing machine for physical metallographic applications. The machine design and construction are principled on using locally available materials for its fabrication. The machine consists of an electrical powered motor, pulleys, belt, rotating shaft, light aluminium alloy polishing disk plate, bush bearing, pillow bearings enclosed in metal casing. The test-running and evaluation of the machine was carried out at different speeds, grits of abrasive papers and on variety of materials (metal alloys, composites, plastic, ceramics) for both dry and wet operating conditions. Testing the machine was done with and without specimen on the rotating table for grinding and polishing. The machine is simple and safe to operate and requires minimum maintenance cost. The specimen size should not be less than 25mm diameter by 10mm thickness for easy hand held polishing operation.

Key words: Variable speed; Abrasive; Grinding; Polishing; Machine fabrication; Metallography