A stranding machine is a type of machinery used in the production of cables and ropes. It is responsible for joining multiple stranding elements together by winding them around a common axis. This process creates stranded conductors inside the cable, which provide flexibility and processability to the final product.
Here are some key aspects and types of stranding machines:
Stranding Process: The stranding process involves rotating and forward movement. The rotation causes the stranding elements to wind around an axis or a center element, while the forward movement is achieved using a capstan.
6-Wire System: The most common and simplest stranding system is the 6-wire system. It consists of a center element around which six wires are helically laid. Each additional layer has six more wires than the previous layer, following a concentric design.
Lay-Length: The lay-length refers to the measurement parallel to the axis that each individual stranding element needs for one complete winding around the axis.
Stranding Direction: The stranding direction can be indicated by observing the rope in the roll axis. A right-stranded rope has stranding elements going from front left to down right, indicated by the character "Z". A left-stranded rope is indicated by the character "S".
Compacting: Compacting is a process used to reduce the cross-section of the individual wires in a stranded conductor. This can be done using a stranding nipple and/or compacting rollers, which change the geometric shape of the cross-section.
Types of Machines: There is a wide range of stranding machines available, depending on the specific cable type, material characteristics, and quality requirements. Some common types include:
a. Tubular and skip stranding lines for steel strands, copper strands, and aluminum strands production.
b. Rigid stranding lines without backtwist for copper strands, aluminum strands, and ropes.
c. Planetary stranding machines with backtwist for steel ropes or cable armor.
d. Closing machines such as drum twisters, bow cablers, and planetary machines.