In this study, wax patterns with composition of 50% paraffin, 30% bees wax and 20% montan, are produced using wax injection machine. The optimal design for injection parameters is sought by using the design of experiment (DOE) and numerical analysis. Taguchi's approach has been applied for the optimization of wax injection parameters. The most influential parameters such as injection temperature, holding time, die temperature and injection time that will provide better and consistent dimensional accuracy to the wax patterns regardless of the noise factors present has been optimized. In order to determine optimal process parameters, experiments have been performed for various process conditions with the design of experiment (DOE) scheduling. Linear contraction of wax patterns was measured. Root Mean Square (RMS) values and dimensional variation were also determined.