Abstract: As the parameters of injection moulding is an optimum problem of multi influencing factors and strong nonlinear, the study on optimum design of injection moulding is developed early. It wasn’t considered that random factors influence the molding quality in existing study. Aiming at this problem, the maximum warpage quantity is selected as a measurement of molding quality, and the method of robust design is provided based on relation degree and Kriging model. Under the quality limit of injection moulding, it can adjust the sigma level in the process of robust optimum automatically. The result of optimum design shows the improved sigma level in maximum warpage. And the dimension tolerance of plastic product is improved by this method, according to CAE and actual injection moulding.

Key words: Injection moulding, Robust design, Kriging model, Relation degree