Resource-saving technology for manufacturing lead-free solder by extrusion

Increasing legislative requirements in the field of environmental safety and limiting the use of lead in new electrical and electronic equipment increase the relevance and economic justification of the search for new low-temperature alloys for solder. This article develops a technology for producing lead-free solder rods and wires using the direct extrusion method. Using a mathematical model of direct extrusion and a computer program, the deformation and energy-force parameters of the manufacture of rods Ø8.0 and Ø15.0 mm and wire Ø2.0 mm from the 52In-48Sn alloy were determined. According to the calculation results, the maximum extrusion forces in the manufacture of the specified assortment are 106 kN. This must be taken into account when selecting direct extrusion equipment. Simulation in the QForm package determined the temperature and speed conditions for the extrusion of rods and wire. It was revealed that technologically the extrusion process can be implemented in the analyzed modes for all standard sizes of products. The alloy is not heated above its melting point. There are also no reasons for loss of process stability and reduction in the quality of the finished product. Strength analysis of technological equipment for the production of rods and wires showed a safety margin of more than 2.1, which is considered sufficient for metallurgical equipment. Using the developed technology, a pilot batch of 100 kg of solder wire Ø2.0 mm wound on coils and 150 kg of solder rod Ø8.0 mm was manufactured for JSC Chelyabinsk Zinc Plant.