A Detailed Report About Yarn Twist(Part One)
Yarn twist is important in textile industry. Especially for the people in the production process. As it’s a big area contains many aspects. I will divide into 2 part. Today is the first part. Let’s start from some examples.
How Does Yarn Twist Affect Fabric
The strength of yarn twist and its direction play an important role in textile. It’s like the hand of magician. They can change the fabric effect and make different patterns on the fabric surface. For example, the high twist cotton yarn can make the voile fabric light, clean surface, breathable, and smooth. By using the high twist rayon fiber to make the plain crepe fabric. It’s the best choice for ladies and kids dress. Sometimes we use low twist yarn to increase the quality for the brushed fabric.
How Does Yarn Twist Direction Affect Fabric?
Here are some examples for how twist direction works on fabric to change the fabric effect and make more patterns. We may still remember the polyester stripe chiffon. (check the below image) It’s in fashion for a long time. There’re 2 different kind of warp yarn with different twist. They construct in certain order. According to the yarn twist and construction, the fabric will show different kind of faded stripes with certain repeat after dyeing. If we do the same in weft yarn, it will show the faded plaid on the surface.
Plaid Chiffon Image
Now you may know how the magic hand of yarn twist works in textile industry. There’s another example. In plain fabric, if the twist direction of warp and weft yarn is different, the fabric will have the same shining surface. In twill fabric, if the direction of warp yarn is in S direction and the weft yarn is in Z direction. The twist direction of warp and weft yarn is vertical to the fabric twill direction. It will have more clear twill patterns on the fabric surface.
What’s The Difference Between S Twist and Z Twist Yarn?
The image below will answer this question.
S And Z Twist
In textile industry, Z twist has another name as left twist. So the S twist is right twist. Normally, single thread is Z twist. Here I have a question for you. What’s the twist direction for the plied yarn of 2 Z twist single thread? It’s S twist. Correct!
Twist Per Unit And Twist Coefficient
Twist Per Unit
We use Tt for the cotton yarn or cotton blend yarn twist unit. It’s a number of twist turns in length 10cm yarn. It’s Te in inch. Means the twist turns per 1 inch.
Tm stands for the twist turns in 1 meter of worst wool yarn and polyester filament.
Tm also stands for the twist turns of regular wool yarn. Or Tm/10 means the twist turns per 10cm. We can find out the relationship between Tt, Te, and Tm by the following formula.
Tt=3.937Te=Tm/10
Te=0.254Tt=0.00254Tm
Tm=10Tt=39.37Te
Twist Coefficient
During the twist process, the fiber inside of yarn becomes longer by the twist strength. The outside fiber will digest more twist strength and become longer. It will deliver a centripetal force to the inner fiber. The yarn will more physical and mechanical change when the twist increasing. For example, the yarn will become tight. The diameter will be smaller. The yarn strength will increase. But the yarn touch feel will be tough and the yarn surface also changes.
In the next part, I will share with you about the following ideas.
Twist shrinkage
How does twist influence yarn.
How does twist coefficient influence the volume, weight nd diameter of the yarn.
The proportion between single and plied yarn coefficient.
So stay tuned for the part two. Click to check more textile knowledge.