Abstract: Four process parameters, mold temperature, melt temperature, holding time, and holding pressure, in injection molding of slender polycarbonate (PC) parts were optimized using GA-BP and RSM methods. The RSM method resulted in the optimal parameter combination of [A3, B3, C1, D1]. The GA-BP method predicted that the minimum axial deformation was 0.0064 mm, very close to the Moldflow simulated value of 0.0063 mm. For 9 groups of random trials, the maximum absolute errors of prediction by GA-BP and RSM were 5.48 % and 7.41 %, and the relative errors were 2.76 % and 3.13 %, respectively. It showed that the combination of GA-BP and RSM provided a high prediction accuracy.

Key words: injection molding, response surface method, polycarbonate