Minimum bend radius of a cable is measured to the inside of the cables curvature, and is defined as the minimum radius one can bend the cable without damaging it, or shortening its life. The cable in the image below has a bend radius of 7cm, for example.
The Trilogy THF flex cables which come standard on all Trilogy Ironless Linear Servo Motors have the following minimum bend radii:
Absolute Minimum = 5 times the cable diameter.
Preferred Minimum = 10 times the cable diameter.
For example, a THF cable with an outside diameter of .28" will have a preferred bend radius of 2.8", and an absolute minimum bend radius of 1.4".
Never design an application for below the absolute minimum flex radius value. If possible, design for the preferred minimum or greater. This will ensure the best possible flex cycle life for your Trilogy flex cables.
Trilogy THF flex cable diameters can be found in the following FAQ: