GB/Z 24636.4-2009

This standard provides a method for designing statistical tolerances in mechanical manufacturing when a specific confidence level is required for the assembly or functional performance of parts. It is applied in the design and production of precision components, such as automotive or aerospace parts, where engineers need to balance manufacturing cost with the probability that a given percentage of assemblies will meet fit and function requirements. The standard guides the calculation of tolerance zones based on statistical distributions, ensuring that the specified confidence level for acceptable product quality is achieved.