钣金弯曲件是现代机器、仪器仪表中数量最多的零件种类之一。结合我所产品的情况看 ,也是数量最为繁多的零件种类之一。计算弯曲零件毛坯长度是制定其工艺方案的前提。通常典型的简单弯曲件如图 1所示 ,其展开长L =L1+L2 -X (修图　 1正系数 ) ,但在各种手册和资料中 ,一般只有 Sheet metal bending parts is one of the most diverse types of parts in modern machines and instrumentation. According to the situation of our products, it is also one of the most numerous types of parts. Calculating the length of the bent part blank is a prerequisite for developing its process plan. Usually a typical simple curved pieces as shown in Figure 1, the expansion of the long L = L1 + L2 -X (Figure 1 positive coefficient), but in a variety of manuals and materials, generally only