Robotic Wire and Cable Selection Tips

It would be nice to go online and simply purchase robotic wire or cable for your robotic application. The truth is, selecting the right wire for robotics isn't that easy. Robotic movements vary and have different levels of demand on the robotic wire. Movement includes repetitive flexing, torsion/twisting and bending at multiple points. Off the shelf wire and cable normally isn't manufactured to endure these types of robotic movement. Robotic wire and has to be manufactured based on the type of movement and use. Construction and material selection are key factors in preventing robot failure. Robotic cable designs begin with material selection. Tell your custom cable manufacturer all about your robotic application and include:

• The type of movement is required of the wire or cable, number of cycles.
• The environment which it will be operating in. Include temperature, contact with fluids or moisture and abrasion resistance.
• Other requirements such as, voltage, EMI, flammability and any special needs.

The more your custom cable manufacturer knows about your application the better your cable design will be.

Material choices depend on the robotic requirements and begin with the conductors. Conductors (except solid core) are made up of multiple strands of fine wire, the more strands in the construction the more flexible and resistant to flex damage the conductor will be. The use of high strand count alloy conductors is recommended for high flex cycles and torsion. Alloy materials are stronger than standard copper conductors and can withstand repetitive flexing and vibration. High strand count conductors are available in several types of configurations), your cable manufacturer can recommend the right one for you.

Insulation and jacket materials also play an important role in the Robotic wire or cable's performance. Selection will depend on the surrounding environment. Silicone insulation and jackets are ideal for chemical resistance, high temperatures and super flexible cable designs. Silicone is not as resistant to abrasion as other materials. Understanding the material properties will help narrow down the choices.

Flexible cables or high flex?

Robotic and automation applications require specialized cables that can handle repetitive flexing and movement. Design engineers must consider using custom cables designed to withstand flexing to prevent product failure and down time down the road. Robotic wire applications don't always require extremely flexible wire and cable, withstanding hi-flex environment is usually the main concern.

Flexible cables or high flex? These two terms are often misunderstood. Flexible can mean the limpness of a wire or cable and is used by some to describe high flex. The term high flex wire and cable is usually used to describe repetitive flexing. Can you have both? Yes you may. Ultra flexible wire designs use high strand count conductors for higher flexibility as does high flex wire. High flex wire normally will use alloys for the conductor material while maintaining the high strand count. High strand count conductors are made up of many fine strands of wire, the higher the number of strands the more flexible and resistant to breaking the wire will be. Depending on the wire gauge, strand counts can be in the thousands. Typical off the shelf wire is available in solid, 7 or 19 strands. These stranding configurations are better suited for static type of applications. When a wire has fewer strands, the strands will fatigue and begin to break under repetitive bending, vibration and flexing situations. As the strands break, conductivity will be compromised and may result in damage to the wire insulation. Conductor stranding is available in a variety of configurations.

For best results for high flex robotic cables need to be designed with high strand count conductors preferably using an alloy for added strength. Insulation can vary depending on the application. When designing the insulation and jacket, the environment must be considered. A few considerations are:

• Chemical resistance
• UV resistance
• Abrasion resistance

For super flexible cables, silicone insulation and/or jacket is a great choice. Silicone is resistant to chemicals and one of the most flexible of material choices. The downside to silicone is abrasion resistance. Other flexible wire insulation and jacket materials choices include TPE, polyurethane and Calmont's Superflex which is a special flexible PVC to name a few. Cable construction and shielding options also play a role in flexible wire and cable. Consulting a custom cable manufacturer and discussing the application, environment and use of the robotic cables prior to product design is recommended. Making the right cable design choices from the start will prevent down time and product failure in the future.