在砂型数字化无模铸造精密成形技术基础上，为实现砂型数字化柔性挤压近净成形创新提出了砂型数字化挤压成形方法，研究了砂型挤压成形优化算法，建立了砂型挤压头阵列包络体积最大值目标函数V(α， X，Y)_max及其约束条件数学模型，优化出挤压砂型近净成形的最优角度和位置，使数字化挤压砂型型腔与数字化设计砂型型腔尺寸逼近，实现砂型数字化柔性挤压近净成形。

Based on the technology of digital precision forming machine without pattern casting,digital extrusion method of sand mold is proposed to get near-net forming sand mold innovatively. Optimization algorithm of sand mold forming with digital flexible extrusion technology is studied. The maximum volume formula,with sand mold cavity attitude and position as variables,enveloped by extruding units envelope surface, V(α, X, Y)_max is established as objective function. And,the restrictions are analyzed. Optimized results of sand mold formed by digital extrusion technology are obtained by numerical iteration method. Extruded sand mold,formed close to the target one,is got by digital flexible extrusion technology with the optimization algorithm. And,near-net forming sand mold with digital flexible extrusion technology are achieved.