What is tolerance stack-up analysis and describe the worst-case method?

Tolerance stack-up analysis calculates the cumulative effect of individual tolerances on an assembly's critical dimension or clearance. The worst-case method assumes all tolerances are at their extreme limits simultaneously, summing all tolerances arithmetically. This conservative approach guarantees 100% interchangeability but may result in unnecessarily tight tolerances. It is calculated as: Total Tolerance = Sum of all individual tolerances in the stack.