弯管机加工的前道工序为下料，下料尺寸如果按照设计图纸中心线的计算往往偏大，这对于多次弯曲加工工件来说尤为突出，并且弯曲后还要进行切割，大大降低生产效率，给弯管机加工带来困难。为此，在实践中总结出如下简便、实用、下料准确的经验计算公式：L：下料尺寸（mm）；L Bending process for the first pre-cutting process, cutting the size of the design drawings according to the center line is often too large, which is more for bending the workpiece is particularly prominent, and after bending but also cutting, greatly reducing production Efficiency, to the pipe bending machine processing difficulties. To this end, in practice, summed up the following simple, practical, accurate empirical experience formula: L: cutting size (mm); L