Development of a uniform-droplet spray apparatus for high melting temperature metals

Abstract

The building and operation of a high-temperature uniform droplet spraying (UDS) apparatus extend the performance and capabilities of powder based manufacturing processes. Although the main concepts of operation of the high-temperature apparatus are typical to the ones currently existing in the Droplet Based Manufacturing (DBM) laboratory, they are implemented with some different systems whose capabilities satisfy the process needs for solder alloys. The motivation of this research is to design, test, optimize, and assemble the new UDS apparatus systems aiming to produce the powder of high melting temperature metal, mainly copper. At first, the limited capabilities of the current apparatuses are revealed and the characteristics of the high-temperature apparatus are presented. A new design concept is set according to these characteristics. The UDS apparatus is then described in detail with emphasis on the newly installed systems that give the apparatus its desirable features. After that, the assembly processes of all the systems are explained. The next step is the testing process of the systems that analyzes and optimizes their performance. At the end, the experimental outcome of this research is presented. In conclusion, partial success in spraying 300 to 700[mu]m copper droplets is achieved. These results are evaluated and their influencing factors are discussed. Further improvements in orifice mounting and prevention of degassing from the crucible and insulation need to be considered for consistent success.