Ultrafine Tin-based Wire Hydrostatic Extrusion Process

Make ultra fine wire carefully is the tendency of the international industry of wire rod. In electronic technical, IT field, the miniaturization of product needs a lot of thin base ultra fine welding wire. Under ordinary processing condition general tin lead welding wire and none lead welding wire easily broken line, can not process 0.3 mm below, reach to ultra fine level. Abroad research in this technical field start very early, now, home ultra fine wire market of welding wire is monopolized by abroad business, tin base ultra fine wire product is major dependent on import. Along with the miniaturization development of electronic chip, this gap of the ultra fine field of welding wire, will affect seriously the tendency that entire Chinese electronic industrial miniaturization develops. This paper thinks that the reasons of traditional processing technology of welding wire can not reach to ultra fine is that plasticity of the solder is not enough, on this foundation, we have analyzed further of hydrostatic extrusion in raising the metal plasticity, put forward the conception of use hydrostatic extrusion to preparation ultra fine welding wire.This paper is first from the contact characteristic of hydrostatic extrusion, uses to press characteristic, brattle-to-ductile transition have analyzed the technology particularity of hydrostatic extrusion, then do a specific analysis of hydrostatic extrusion, and on the found of imaginary speed site, we have carried out the calculation of parameters such as hydrostatic extrusion pressurization extruding force, best mould angle, deformed dead band and limit mould angle, have analyzed the relation of extruding force and limit mould angle,extruding force and reduction, the correlation between extruding force and friction factor. Discussed friction mechanism of the hydrostatic extrusion with adhesion 梔uctility binary friction theoretical, have analyzed the 3 kinds of lubrication stateof hydrostatic extrusion.On the foundation of theoretical analysis, have carried out design of hydrostatic extrusion test equipment. Have elaborated basic design principles of extruding room design and the way of leading pressure into and the aspect such as mould design and sealed design. Draw equipment blueprint and have completed the processing production of equipment.Using the equipment that designed independently, technology of ultra fine tin base solder wire have been trial test, reach the relation of pressure and friction force, have accumulated perforation method, extrude medium select principle and pressurization speed control, have discovered the effect " spurt to continue". Have prepared 0.2 mm ultra fine tin base welding wire successfully, have determined the process preliminarily of 0. 1 mm ultra fine tin base welding wire. Through analyzed and test, confirmed that hydrostatic extrusion can not only raise the density and tensile strength of metal that can also still raise plasticity of it's product and twine character.All these prove using hydrostatic extrusion preparation ultra fine tin base welding wire is feasible. This paper has still analyzed social benefits and the economic benefits of continued this technology research in detail , at the same time explained some difficult in industrializing , has put forward the method of solution , has shown clearly goal for later research and development.