Tolerance analysis is the general term for activities related to the study of accumulated variation in mechanical parts and assemblies.
Statistical tolerance stackups evaluate the maximum and minimum values based on the absolute arithmetic calculation combined with some method for establishing likelihood of obtaining the maximum and minimum values, such as Root Sum Square (RSS) or Monte-Carlo methods.
The individual variables are placed at their tolerance limits in order to make the measurement as large or as small as possible.
Designing to worst-case tolerance requirements guarantees 100 percent of the parts will assemble and function properly, regardless of the actual component variation.
While no official engineering standard covers the process or format of tolerance analysis and stackups, these are essential components of good product design.
Tolerance stackups should be used as part of the mechanical design process, both as a predictive and a problem-solving tool.
Understanding the tolerances, concepts and boundaries created by these standards is vital to performing accurate calculations.
The vectors are joined tip-to-tail, forming a chain, passing through each part in the assembly in succession.