6. Conclusion

Functional dimensioning allows the widest possible tolerances. It should therefore be applied to the definition drawing to give the methods the widest possible transfer possibilities when they consider it advantageous, particularly in the numerical control of machine tools.

In mass production, we have to abandon the old principle: all parts are good and all lie within the tolerance interval.

The new approach assumes that methods, manufacturing and control know their "capability" (coefficients Cp and Cpk ) and that the tolerance interval set by the studies is respected with a certain probability (6 σ in general, i.e. 2.7 parts "out of tolerance").