An alternative method to tolerance transfer for parts with 2D blueprint

Abstract

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.

Keywords:

• Tolerance transfer
• Tolerance charting
• 2D blueprint