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.
Robust Design PRinciples: Master Guide Ratio and Sensitivity

Guide Ratio to Avoid Jamming
• 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.

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.

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