Some feasible methods were summarized for aluminum alloy thin-walled casting blister for Boeing aircraft. The use of zigzag sprue with three curved paths ingate is beneficial to reducing oxidation

gas pick up and entrapped slag

and the use of step-to-step filling is helpful to form good solidified temperature gradient

and the use of 1 -2 h additional core baking at 150±10℃ before mold assembly is favorable to eliminating gas hole.