An alternative method to tolerance transfer for parts with 2D blueprint
提出一种新的二维公差传递方法，通过建立二维链方程并求解，结合方差与偏差累积理论评估等效公差，适用于满足初始蓝图规格的公差分配。
The classic tolerance charting method to allocate working dimensions and tolerances, is a particular case of tolerance transfer between different dimension schemes. Tolerance transfer allows tolerance allocation for a new dimension scheme that fullfils initial blueprint specifications. This paper suggests a new method to tolerance transfer that allows the evaluation of dimensions and their tolerance which are equivalent in 2D problems. Initially, a method that is able to consider dimensions, angles, and orientation tolerances is established. The first point that is indicated in the proposed method is how to establish the equations for each 2D chain through 2D graphs. In an intermediate step, a strategy to solve the 2D equations, yielding relations between the tolerances is proposed. Finally, the equivalent tolerances are evaluated, considering both the variance accumulation theory and the deviation accumulation theory. The proposed methodology has been applied to different cases with satisfying results.