The plastic injection molding is known to be the most effective process for producing discrete plastic parts of complex shape to the highest precision at a low cost. And the placement of a gate in an injection mold is one of the most important variables of the total mold design

because it influences the manner in which the plastic flows into the mold cavity. In the present paper

some detrimental factors that affect the product quality are assessed.Such assessment can be obtained from numerical simulation results

and can construct a gate location optimization problem. A genetic algorithm is used to search the optimum gate design. The examples indicate that the described methodology can be used effectively to obtain the optimum gate design of single-gate and multi-gate mold.