Structure analysis of the conical heating hole for waste printed circuit boards disassembly

Abstract

The component disassembling technology of printed circuit board is taking on more importance in the field of electronic waste disassembly. When disassembling electronic components from waste printed circuit board, its implementation programs are to inject hot air into printed circuit board through spray nozzle and melt the solder joints through thermal convection. The structure of air heating outlet for disassembling electronic components from waste printed circuit board is investigated to reduce energy consumption in solder melting process. This paper proposes a structural analysis method of conical heating holes to reduce the energy consumption of hot air and improve the temperature uniformity in solder melting process. With advantages of high efficiency and low-cost, numerical simulation method is totally used to obtain optimal dimension parameters of the conical hole from a wide range of optional parameters. The numerical simulation takes air as the heating medium and adopts the mode of heat convection under optimal melting temperature range (200–230 ℃). The optimized results of the parameters of a single conical hole and multiple conical holes are obtained based on numerical simulation. When the distance between the inlet and the substrate is 50 mm, the optimal inlet temperature and velocity are 235 ℃ and 8 m/s, respectively. For a single conical hole, the optimal inlet height, top diameter, and angle are 6 mm, 16 mm, and 20°, respectively. For multiple conical holes, the optimal distance between the center lines of two inlet ranges from 50 mm to 56 mm.