Velocity calculations for all rodless cylinders need to differentiate between final velocity and average velocity. For example: Stroking a 10-inch magnetically coupled cylinder in one second yields an average velocity of 10 inches per second. To properly determine the forces for cushioning, it is important to know the final (or impact) velocity. Rodless cylinders accelerate and decelerate at each end of the stroke. Therefore this acceleration must be considered (see diagram at left).
If final (or impact) velocity cannot be calculated directly, a resonable guideline is to use 2 x average velocity.
Since the piston on a magnetically coupled actuator is not physically connected to the carriage and load, it is recommended that an external means of cushioning or stopping always be employed.