对压延系数较小,需要两次拉伸成形的筒形零件,可以在一付模具上一次完成二次拉伸。我厂这类模具有两种形式,对大中形零件采用正、反二次拉伸模;对小形零件采用阶梯式复合二次拉伸模。 For the rolling coefficient is small, the need for two stretch forming cylindrical parts, can be completed in a mold on the second stretch. I have two types of mold factory in this form, the large and medium-sized parts with positive and negative secondary tensile modulus; small parts using stepped composite secondary tensile modulus.