Method for confirming accurate zero-allowance blanking length of straight pipe to obtain bent pipes

The invention discloses a method for confirming an accurate zero-allowance blanking length of a straight pipe to obtain bent pipes. The method comprises the steps of setting two bending angles and setting parameters related to experimental measurement separately; building a mathematical model; and changing original pipe bending allowance blanking calculation into accurate zero-allowance blanking calculation with the assistance of bending springback angle calculation according to the number of bent sections of the pipe in a design drawing, the forming angle of each section of bent pipe and the related model, thereby achieving accurate bending processing of the pipe. The problem that pipe bending processing of a domestic pipe fittings processing enterprise at present is geometrically approximate to an allowance blanking method can be fundamentally solved; and accurate zero-allowance blanking calculation of pipe bending processing is achieved. Meanwhile, digital measurement equipment is directly connected with i