Tolerance Stack-Up Analysis: Including Forces and Deflections

Don't let overlooked mechanical deflections compromise your design.

A minor deflection can be the tipping point between sufficient clearance and assembly failure.  

Deflection occurs when forces act on a product, such as weight, force, user input, or acceleration.

Here, thet op part of the frame deflects under the weight of the top component.

Keep as much structural integrity in the parts as possible to ensure minimum impact of external forces. This is done by material selection, decoupling and placing moment of intertia optimal in the parts.

Make estimates by simple beam calculations.

In many engineering scenarios, deflections can be calculated using idealized analytical expressions. Whether you are dealing with spring deformations or standard beam deflections, these formulas provide a fast, accurate way to account for structural deformations.

The analytical expression can be included directly in the tolerance stack.

When deflections are too complex to calculate analytically, they can be simulated using Finite Element Analysis (FEA). Once simulated, the FEA results can be added to your tolerance calculation as a separate parameter.