The systematic approach to analyze one of the main aspects of jewelry casting processes, flask burnout cycles, is presented. Basic factors of burnout that affect the quality of casting are discussed in detail. Special attention is devoted to understanding the principles of the heat transfer used in different types of furnaces. Directions for the development of optimal furnaces are given. Chemical and physical processes during the melting and burning out of wax are described in detail. Our chemical-kinetic calculations indicate that the wax burning out with a sufficient amount of oxygen in the furnace atmosphere is much more efficient than the combustion of leftover carbon. This leads to the conclusion that the stage of wax burnout should be optimized very carefully in order to avoid gaseous porosity in jewelry castings. Gas formation inside the flasks due to chemcial reactions in the system is analyzed, and the equilibrium temperatures in flasks are also estimated. Based on analyzed chemical and physical properties of casting processes, several directions for technological improvement are outlined.

Authors: Anatoly Kolomeisky & Sergei Kazantsev