Specifying cable in applications characterized by repeated motion should allow for four key qualities: allowable bend radius, life cycles under constant flexing, package constraints, and environmental factors.

The bend radius of Cicoil Flat Silicone cable, like that of any flat cable, depends on the gauge of the wire and type of conductors used in the cable. In general, the finer the gauge of the conductors, the smaller the allowable bend radius. Flat cables using PTFE jackets have a bend radius more than twice as large as Cicoil Silicone cables, given that each cable contains the same conductors. Thus Cicoil Silicone cables can serve in uses that may not be suitable for PTFE cables, as they will fit in a more compact space.

Most industrial automation equipment today operates 24/7, often with robotic elements that execute rigorous motions repeatedly, sometimes thousands of times a day. These applications stress not only the moving parts of the machine, but also the electrical cabling. Engineers spend considerable time sizing electromechanical movers, but often give little thought to whether the cabling is sized properly. The frequent result is that the cabling won’t handle the rigors of the application, resulting in costly premature failures.

In fact, industry research has shown that wiring and cabling causes over 50% of the quality and reliability issues in automation equipment. For these reasons, designers should plug in a safety factor to ensure cabling will meet flex-cycle needs.

Standard cabling will not last in these applications, as the cables are not designed to flex continuously. Flat cables are best for continuous flexing. Their wire conductors can individually flex in a single plane, which provides optimum flex life.

There are two key considerations for cable that must last a long time in flexing applications: the wire conductors and the cable jacket.

Under continuous flexing, conductors containing multiple strands of fine-gauge wire will last the longest. For example, standard 28 AWG is typically composed of 7 strands of 36 AWG wire, while 28 AWG high-flex wire is composed of 19 strands of 40 AWG wire (or even finer gauge). The finer-gauge base wire exhibits less coldworking under constant flexing. The minimal cold-working lets these wires last through tens of millions of flexing cycles
(see ‘Anatomy of High Flex Wire’)