Sum the absolute tolerances of all components in a linear dimension chain to conservatively assess assembly clearance or interference.
线性尺寸链最坏累积 = 各环公差绝对值之和。
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Worst-case stack-up | T_total = sum T_i, assuming every contributor sits at its limit simultaneously | ISO 8015:2011, Geometrical product specifications (GPS) - Fundamentals - Concepts, principles and rules |
| Statistical stack-up | For independent contributors, T_total = sqrt( sum T_i^2 ) | NIST/SEMATECH e-Handbook of Statistical Methods (variances of independent terms add) |
| Cost of the worst case | Guarantees full interchangeability at the price of the tightest component tolerances | ISO 8015:2011, Geometrical product specifications (GPS) - Fundamentals |
| Trade-off of the statistical method | Accepts a small fraction of out-of-tolerance assemblies in exchange for wider tolerances | NIST/SEMATECH e-Handbook of Statistical Methods (statistical tolerancing) |