Response Surface Methodological Approach in Jewelry-Bodied Casting

Jewelry-bodied casting is the most important upstream process causing defects in jewelry industries. Three process parameters, that are, Ingate, Angle, Mold Temperature and Pouring Temperature which influence to the density of products were studied using response surface methodological approach. Casting materials were three types of silver alloy. A 2³ full factorial central composite design (CCD) and a small composite design (SCD) were employed. The relationships of Ingate Angle, Mold Temperature and Pouring Temperature and density of products were determined by using regression analysis. Two models of expected function were used, that are, quadratic model and exponential model of linear equation. The appropriate models were determined and the comparisons of different designs were conducted. The results indicated that small composite design was more efficient than central composite design, quadratic models were more appropriate than exponential models of linear equation in all types of silver alloy using CCD and exponential models of linear equation were more appropriate than quadratic models in all types of silver alloy using SCD.

Keywords: response surface methodology, central composite design, small composite design, jewelry-bodied casting

Corresponding author: E-mail: g4585016@ku.ac.th and fengpsa@ku.ac.th