Spinning: What it is and the different methods
Spinning is the process of converting fibres into yarn, which is a continuous strand of fibres used in various textile applications. The spinning process involves twisting the fibres together to create a cohesive and continuous strand of yarn that can be used for knitting, weaving, or other textile processes.
There are two different methods to achieve this: ring spinning and open-end spinning. While different, both methods involve two stages: preparation and the actual spinning.
The history of spinning
Back in the day, before the Industrial Revolution, spinning was a manual operation. These days, there are two predominant spinning methods. And each of them has its pros and cons (read more), the choice of spinning method depends on various factors such as the type of fibres being spun, the desired yarn properties, production requirements, and cost considerations.
The old-timer of spinning is ‘ring spinning.’ It’s been around since in 1828 when the first ring spinning machine was invented in the US. Of course, the technology has been considerably modified since then, but the basic concept remains the same.
Ring spinning was the method of choice for denim producers until the 1970s. That’s when the industry turned to ‘open-end spinning,’ also known as ‘rotor spinning,’ which was invented in 1963 in Czechoslovakia.
In recent years-fuelled by the advancement of denim made from stretch yarn (which can only be made with ring spinning) and the growing demand for “authentic” denim-ring spinning has regained the position as the industry’s go-to spinning method.
Ring spinning was the method of choice for denim producers until the 1970s, when the industry turned to open-end spinning, also known as ‘rotor spinning.’
But with the advancements in stretch denim and the growing demand for “authentic” denim, ring spinning has regained the position as the industry’s go-to spinning method.
The spinning processes
In the preparation stage, the fibres are parallelised and elongated. The goal is to take full advantage of the length of the fibres to get durable and resistant yarn.
Once the fibres have been parallelised and elongated, torsion enters the picture. This is where the actual spinning happens as the fibres are twisted around each other. And this is where the two methods differ.
The first stage is preparing the fibres by parallelising and elongating them. The goal is to take full advantage of the length of the fibres to get durable and resistant yarn.
It starts with the machine known as the ‘bale plucker,’ which picks the cotton fibres off a row of cotton bales. The fibres are then mixed and cleaned to remove leftover seeds from the ginning process.
Next, the fibres fall into two differentially rotating cylinders full of needles in the ‘carding machine.’ This starts the parallelising process.
Applying torsion (in other words, the actual spinning)
Once the fibres have been parallelised and elongated, torsion enters the picture.
This is where the actual spinning happens as the fibres are twisted around each other. It’s here the two spinning methods differ.
Ring spinning
Ring spinning is the most common method used for spinning natural fibres like cotton. In this method, a thin strand of fibres, called a roving, is drawn through a small eyelet, or “traveller,” and twisted by a spindle that rotates around a ring. Enclosing the spindle is a ‘ring rail’ that gives the method its name. The twist imparted by the spindle holds the fibres together, forming a continuous strand of yarn that is wound onto a bobbin.
Pros
Higher yarn quality
Versatility: can be used for a wide range of fibres
Less fibre waste
Lower energy consumption
Cons
Lower production rate
Higher equipment cost
Open-end spinning
Open-end spinning, also known as rotor spinning, is a method used for spinning both natural and synthetic fibres. Compared to ring spinning, you don’t have the roving frames, the drafting system or the ring and traveller enclosing the ring cop to apply torsion. Instead, the sliver is fed directly into the ‘spinner’ by a stream of air, delivering it to a ‘rotary beater’ that separates the fibres into a thin stream. Air then carries the fibres into the V-shaped groove with a rotor at the end. As the rotor turns, the fibres are twisted.
Pros
Higher production rate
Lower equipment cost
Less labor-intensive
Cons
Lower yarn quality
Limited fibre compatibility
Higher fibre waste
One thing both ring-spun and open-end yarn have in common is that their three characteristics are carefully controlled to design the yarn to be exactly like the yarn designer wants it.
In conclusion, ring spinning and open-end spinning each have their strengths and weaknesses, and the choice between them depends on the specific requirements of the textile production process, including yarn quality, production rate, fibre compatibility, equipment cost, and labour costs. Ring spinning may be preferred when higher yarn quality is required, and cost considerations are not a limiting factor, while open-end spinning may be suitable for high-volume production requirements where production rate and cost efficiency are prioritized over yarn quality.