Tolerance Stack-up Analysis

Training On Tolerance Stack-up Analysis

Prepared by K.PRASANNA Keykert Team

Tolerance Stack-up The objective of Tolerance stack-up analysis is to find out the maximum/minimum clearance/interference of mating parts in an assembly. Tolerance stackup analysis is to find-out the minimum and maximum value of “G”

Purpose • To ensure the proper functioning of the  product • Design verification • To understand where the design allows freedom

Phase of Stack up Analysis • Part drawings release • Manufacturing • Production • Engineering changes

Input for the Stack-up Analysis • Components involved in ASSEMBLY • All part drawings • Sequence of assembly

Calculation The value of “G” can be calculated by the formulae given below G=L1-(L2+L3+L4+L5+L6)

General Procedure • Add the values of parts that are accommodating the inner parts (L1) and subtract the values of the  parts inside (L2,L3,L4…). • The min/max values can be obtained when the Upper and Lower limit values are considered. • Consider all the possible combinations of dimensions for making the minimum and maximum values. • Consider the corner fillets and diametrical difference of components also to get the exact mating position.

Example

Exploded View

Section View

Output for the Stack-up Analysis • Report containing the following details  Assembly  Parts

involved with revision

 Area

where the stack up is done

 All

dimensions with a specific variable

 Attach  Date

part drawings if possible

on which the stack up is done

 Formulae

involving dimensions to calculate the min/max stack up