Enter the diameter of the piston, diameter of the rod, and the pressure between the piston and rod into the calculator to determine the retraction force.

## Retraction Force Formula

The following equation is used to calculate the Retraction Force.

RF = P (pi*Dp^2/4 – pi*Dr^2/4)

• Where RF is the reaction force (lbf)
• P is the pressure between the piston and rod (psi)
• Dp is the diameter of the piston (in)
• Dr is the the diameter of the rod (in)

To calculate the retraction force, subtract the area of the rod from the area of the piston, then multiply by the pressure.

## What is a Retraction Force?

Definition:

A retraction force is the total force required to retract a pneumatic cylinder with with a piston and rod.

## How to Calculate Retraction Force?

Example Problem:

The following example outlines the steps and information needed to calculate the Retraction Force.

First, determine the pressure . For this example, the pressure is 50 psi.

Next, determine the diameter of the piston. In this case, the diameter of the piston is found to be 5 in.

Next, determine the diameter of the rod. For this problem, diameter of the rod is measured to be 2 in.

Finally, calculate the Retraction Force using the formula above:

RF = P (pi*Dp^2/4 – pi*Dr^2/4)

RF = 50* (3.14159*5^2/4 – 3.14159*2^2/4)

RF = 824.66 lbf