Warm sheet hydroforming process has being investigated in recent years with its high formability feature. Warm hydromechanical deep drawing (WHDD) which is a type of the warm sheet hydroforming process is important for deeper parts. To determine the formability of the WHDD process the most convenient tool is Limiting Drawing Ratio (LDR). But determination of the LDR accurately needs using of the most convenient tool dimensions. In this study optimal geometrical parameters were investigated by FE Analyses of the process. Consequently optimum punch and die diameters and optimum punch nose and die entrance radiuses were determined for accurate LDR value.