What is yarn spinning and what equipment is needed to prepare the fiber?
Textile fibers can be manmade or naturally derived. Natural fibers are cellulose-based, protein-based, or mineral-based while manmade fibers are primarily based on synthetic polymers but also employ natural polymers that have been chemically altered to produce a new fiber. Every yarn production begins by preparation of these fibers.
This process begins via a bale opener removing these fibers layer by layer and gently separating these fibers into small tufts. Air currents transport these tufts to opening and cleaning machines for gentle preparation and onto precision blending machines that mix the tufts from a singular raw material or from various raw materials based on the application and finished product requirements. Once these pre-cleaned tufts are mixed systematically, they are carded. The process of carding disentangles, cleans and intermixes the fibers to form a web. This web is gathered up in loose, untwisted ropelike strand which is fed into a can for storage and subsequent processing.
In preparation for spinning the card sliver is combined with other slivers on a draw frame and simultaneously drawn. This process straightens the fibers and mixes or blends the fibers of each sliver to yield a more homogeneous end material.
What are some of types of spinning?
Depending on the requirements of the end product, different spinning technologies can be employed.
There are different types of yarn spinning systems. The equipment and process utilized from a fiber to a blended sliver is similar from this point forward, the equipment moving forward in the process can vary. There are various types of yarn spinning systems. We will concentrate on four systems that have extensive use in industry today.
• Ring spinning:
It is one of the most widely utilized types of yarn spinning systems. Ring yarn is a traditional product in the textile world and is characterized by its enormous versatility. The draw frame slivers are first fed into an auto leveling draw frame to balance the thickness. High sliver evenness warrants consistent yarn quality. From the draw frame sliver, the roving frame forms a preliminary yarn or roving. After passing the drafting unit of the roving frame, the sliver is given a slight twist for the first time in the process to increase the strength of the roving. The rovining is fed into the drafting system which the fibers are drawn and parallized. The fine sliver is wound onto the tube by means of a rotating traveler on the ring. Through this process the yarn receives its final twist.
• Compact spinning (Condensed spinning):
Compact yarn is created in a similar way. In most cases, it is additionally combed and thus refined. For the coming process slivers are combined to form a lap and short fibers are combed out. Also, in compact spinning, the roving frame is used for preparation. The roving enters the drafting unit of the compact spinning machine, in which it is drafted to the required yarn count. The fibers are compacted via vacuum.
• Rotor spinning:
The strength of rotor spinning lies in its high productivity and its great flexibility regarding raw material. After leaving the autoleveller draw frame, the sliver is directly fed to a rotor spinning machine. The sliver is opened, and single fibers are fed into a rapidly rotating rotor and are distributed around its circumference temporarily held there by centrifugal force. The yarn is withdrawn from the rotor wall, and, because of the rotation, twist is generated as it is taken of via a central nozzle.
• Air jet spinning:
The fourth system available on the market is the air jet spinning system. It is relatively the newest spinning technology and allows a far higher productivity compared to the other spinning technologies. In this technology the draw frame sliver is fed into the machine and is forcefully drawn. Air is driven through small holes positioned tangentially to the yarns surface and this causes the yarn to rotate and consequently wound by airflow. By using two air jets operating in opposing twist directions, it is possible to produce yarns with more controlled properties and complex structures.
Are there any performance challenges/limitations users need to be mindful of when it comes to the current generation of yarn spinning equipment?
One of the most challenging issues associated with many types of yarn spinning equipment currently is working with recycled fibers. Recycled fibers obtained from fabric scrap wastes are often times characterized by its low-quality properties in terms of inhomogeneous fiber type and non-uniformity of distributed short fiber lengths. Both of these qualities negatively influence the production process and the resultant quality of the yarns made from it. One of the common ways to utilize recycled fiber in yarn production is to blend it with virgin fibers.
What does the next 10-15 years look like? Where will fiber equipment for textiles be then?
The next 10-15 years will see continued growth of use of recycled fiber. This will be a result of both an increased consumer demand for products utilizing reclaimed and recycled fibers as well as increased pressure in developed economies to reduce landfill textile and fiber waste. Just as developing economies have become more resistant to accepting recycled plastic waste, it may be anticipated that similar pushback may occur against the export of waste clothing and fabric. This will result in the need for domestic approaches to repurposing waste fiber and recycled fabrics. Overall, the demand for circular fiber-to-fiber processes are going to increase.
The technologies needed to identify and collect specific fibers will play a significant part in the speed and cost of addressing this challenge and opportunity. Automation will be necessary in developed markets to mitigate cost challenges. To facilitate this, the fibers that will be run through tomorrow’s equipment will need to be more easily identified at end of life. That could manifest in the form of a polymer additive or finish for identification or for easing material deconstruction. The scale and speed of the equipment will also increase while also becoming increasing more energy efficient. Beyond energy efficiency, there will need to be focus on water consumption and treatment, with emphasis on containment of microplastics generated in the deconstruction and recycling processes.
Overall, these challenges and consumer demand for product life cycle transparency will drive innovation in machinery and material design for both virgin fiber production as well as fiber and fabric recycle.
As director of education and technical affairs, Matt presents regular training related to nonwovens and filter media from INDA’s headquarters in Cary, NC. For more information about upcoming training opportunities, visit inda.org/education.