High Efficiency Classification Technology Research For The High Quality Sn-Pb Powder

Powder technology is one of the most important basic technology to support high-tech industrial. The classification technology of powder is important part of powder technology. The welding powder used by SMT technology has two traits including high specific gravity and high requirement of non-oxidizability that make classification hard for high quality Sn-Pb welding powder .But the turbine flow classifier used widely in industry can not be satisfied with the requirements of high quality Sn-Pb welding powder, it's high speed rotating rotor makes heat motion intense. As a result , oxygen content of powder has been increased ,so the quality of production can not be guaranteed.In this paper the design scheme of new cyclone-type separator was presented according to such characters of Sn-Pb welding powder as high gravity and oxidizability and the theory of cyclone classification, the structure of conventional cyclone separator was improved, and new cyclone separator was developed. Through researches on three primary processing parameters such as the wind rate of blast airfan of cyclone separator,the second wind rate and particle flux thrashing structure, optimal processing parameters were obtained: ten holes for second wind rate,7.2mm aperture and frequency of blast airfan of 40HZ.Results show that compared with products obtained by turbine flow clarifier classifying Sn-Pb powder the grain size of clarified powder reached 25 um, and oxygen content dropped up 30ppm.Comparing to old process of factory , using new equipment of classification has decreased process , knocked down, improved quality of product a lot. In conclusion, the quality of product satisfied the requirements of clients.