Abstract: A threedimensional slice gear model that takes modulus and tooth number as the variables was formulated,and Moldflow was used to establish the reasonable cooling and gating system and to analyze the gear model.The relationship curves between the two variables and the target parameter (maximum warping caused by shrinkage) were made. It was found that the target parameter value linearity increased with increasing number of teeth when the modulus kept constant.The tilt of each line was also different and the slope of straight line became greater with increasing modulus when the modulus kept different.The fitting curves was obtained with Matlab.

Key words: injection molding gear, modulus, tooth number, warping deformation, least squares estimate