The aspects of technology and economy in processing aluminum scrap into fence ornament products at small and middle sized and enterprises in Lampung Province

Abstract

Increasing building in property sectors causes chain effects in many of its supporting fields. One of them is the fence construction. Fence nowadays is not only functions as separator between a main building and other open spaces but it also has prestige values for the owner of the building. Fence ornaments continue to develop over time from its form, raw material, to its making process. Fence makers start to gradually abandon cast iron for fence ornament raw material. The aluminum becomes an alternative raw material in the fence making process. A research on the technological and economy aspects of aluminum scrap processing into fence ornament was conducted. From the technological aspect, small and middle sized industries were suggested to use batch system (50 kg/batch) with solid-fuel-based crucible furnace. The furnace dimension was 390 mm diameter and 440 mm height. Furnace isolation used fire brick type SK 32 with 240 mm thickness and 700 mm of furnace height. The molding process used sand molds method and used local raw material. Ratio of scrap raw material to ornament product was 1.1-1.3, while ratio of solid fuel use was 1.5-2.1. It took 6 hour / batch for smelting process with temperature of 600-710°C. From economy aspect, it took investment cost of Rp. 210,000,000 to start aluminumscrap smelting business into fence ornament product. The financial analysis obtained net present value (NPV) of Rp. 176,699,790; net B/C (benefit/cost ratio) of 1.84; and internal rate of return (IRR) of 31.12%.