"Tested" by Adam Savage: An in-depth review of the world's best keyboard.
Watch the video review now

Want to design mechanisms that will never jam?

This page and video will cover the topics of guide ratio and sensitivity and a few simple principles to make robust mechanisms that will never jam.

Home

/

Robust Design Principles

/

Guide Ratio

Robust Design PRinciples: Master Guide Ratio and Sensitivity

Guide Ratio to Avoid Jamming

The simple equation to remember to ensure that a slider mechanism will not jam.

• Ensure that B/2A is greater than the friction coefficient between the slider (blue) and the frame (grey).

Optimize Guide Ratio

The rule of thumb to ensure the best sliding capability of a slider with as little friction as possible (and with minimum variation):

Minimize A (ideally move the point of attack to the center).

Maximize B (increase the distance as much as possible).

Understanding Sensitivity

A sensitivity analysis reveals sensitive parameters in a design/calculation.

The sensitivity value represents a gradient/slope for a parameter in an equation.

• It is calculated by adding variation of 0.1 (absolute) to a given parameter and comparing it the end result.
In example a sensitivity of 80 corrosbonds to a 0.1 unit change in the given parameter, then impacts in a 8 unit change in the end result. A sensitivity of 20 corrosbonds to a 2 unit change in the end result.

• Sensitivity studies are useful to identify tricky parameters and it is always adviced to try to lower the sensitivity as much as possible by all parameters.

Software interface showing tolerance box parameters and a diagram of nested colored boxes labeled A, B, C, and D with a conclusion stating there will always be clearance.

Point 9 - Make a Conclusion

• After adjusting the parameters, the design now ensures that clearance is always maintained.

• Now we write in the conclusion: "There will always be clearance"

Ready to work with sensitivity calculations?

RD8 software will compute sensitivity for you.

A feature that will save you time, quality and efforts if used correctly.

Laptop screen displaying a 3D model of a mechanical device with a tabular interface showing tolerance parameters and status indicators.

Make sensitivity analysis Easy - Talk to an Expert to get to know the RD8 Software

Want to learn more about the RD8 Software?
We brief you on the main functionality in 1h
We check if the solution matches your needs
Get contacted by an RD8 Expert
Portraits of three professional men smiling, dressed in business casual attire, arranged side by side.

By submitting, you accept RD8's Privacy Policy and Terms of Service.