SuperNX / Learn
Learn
Engineering notes on tolerance-chain analysis, limits & fits, and NX PMI — the math behind what SuperNX automates.
-
ISO 286 Fits Explained: H7/g6, Hole-Basis, and How to Actually Choose
The ISO 286 limits-and-fits system decoded: what the letter and the grade number mean, hole-basis vs shaft-basis, real clearance numbers for the fits you will actually call out.
-
Tolerance Analysis on NX PMI: From Semantic Annotation to Proof
PMI tells the model what is allowed; analysis proves the assembly still works. How Siemens NX PMI actually works, the semantic-vs-decorative distinction, and getting results back onto the drawing.
-
Tolerance Stack-Up Analysis: Worst-Case vs RSS — a Working Guide
How tolerance stack-ups actually work: the worst-case and RSS formulas, a fully worked shaft-and-ring example, and where hand calculation starts to break down.
-
Worst-Case vs Statistical Tolerance Analysis: Choosing on Purpose
A decision framework: when worst-case is non-negotiable, when RSS legitimately saves money, hybrid strategies, and the mistakes that turn statistical analysis into a liability.