Twisting, Assembling and Stranding

Twisting, Assembling and Stranding

Twisting High Performance Fibers

Twisting is the process of combining filaments into yarn by twisting them together in order to even out length differences on the filaments and make a compact yarn. Many high performance fibers benefit from the improved load sharing that twisting allows. This process also improves the processability of the yarn during knitting, weaving, or braiding processes. It enhances the uniformity and smoothness and can be used to optimize strength and elongation of a fiber bundle. Thus twisting increases resistance to yarn traction, enhances pliability, enables a round yarn shape, and improves working conditions in subsequent processes besides other advantages.

Understanding the Process
Twist in general refers to the number of turns applied around the yarn axis. Optimum twist levels vary with the material, fiber size, yarn size, end use, etc. However, excess twist results in a reduction of yarn resistance. Twist is usually measured in TPM, the number of twists per meter. Further clockwise and counter-clockwise twists are distinguished: A clockwise twist is known as the Z twist and a counter clockwise twist is known as the S twist. Ring twisting and double twisting (Two-for-One twisting) are common methods used for twisting yarns. We use both ring twisters and double twisters (Two-for-One) of renowned brands such as Galan, Twistec, Barmag and Lezzeni.

Ring Twister
A ring twister consists of a ring frame, spindles, draughting rollers, and a creel loaded with bobbins of roving. The roving (unspun fiber) passes downwards from the bobbins to the draughting rollers. The roving passes through a thread guide down to the spindle assembly, where it is threaded though a small ring called the traveler. The traveler moves along the ring, what gives the twister its name. From here the fiber is attached to the existing fiber on the spindle. Ring twister are appreciated because of the flexibility of production they offer. Ring twisters can process any kind of yarn and can be used for different products. It is especially suitable to process very thin or delicate fibers.

Two-for-One Twister
With the Two-for-One twisting process each mechanical spindle revolution imparts two twists to the yarn so that the yarn receives two turns with one revolution of the spindle. The pot with the untwisted yarn is kept stationary on the spindle rotor. The yarn is then unwound from this pot, enters the rotating upper part of the spindle, and exits through the opening of the spindle rotor. The yarn receives its first turn within the spindle rotor and the second turn within the yarn balloon. This twisting method increases the strength and the smoothness of the yarn. Further it achieves better coverage with the same yarn volume and thus reduces material cost, increases higher elastic resilience, wear and tear resistance, and water absorbency of the fibers. Twisted fibers are frequently used in several industries with substantial success:

 

  • Car industry and Aeronautics
  • Geotextiles
  • Packaging and Transport
  • Personal protection
  • Sports equipment
  • Household
  • Agriculture
  • Industry belts, Insulation, Hoses

 

Assembling

Assembling or plying is the process of merging different yarns. The difference to stranding is that there is no twist put on the yarn and the different yarns are merely assembled together. This process is typically carried out in order to obtain a certain thickness or strength of the yarn. Assembling is usually followed by twisting or stranding (see below) and therefore a pre-processing process.

Stranding

Stranding is the process in which single yarns are merged and twisted to create thickened yarns, which are also called rope ends. These yarns are used for the manufacturing of thicker ropes and round slings. For this process we make particular use of state-of-the-art Roblon machines. We can supply strands of all high performance fibers up to 80.000 dtex.