The spinning is based on mechanical procedures and unlimited length with unlimited raw materials.
These materials or elements can be divided into 3 classes:
- Short filaments (short fiber) such as cotton, wool etc.
- Intermediate length filaments such as hemp, jute and wool.
- Filaments of determined length such as silk.
In the process we will first work with machines called flap, card, which is reduced to cleaning the fiber. The following machines of the process to regularize the base of the fiber for further processing..
When talking about yarn or yarns, or even of simple fibers twisted with each other, we talk about the base material (this is important no matter what the desired output is) and since ancient times, it has been marketed based on its quality, with a measure of length, thickness and weight.
Cotton yarns, wool, silk, etc., even if they are apparently cylindrical there is more variation, and still lack a lot of what we have come to expect in modern life, uniformity, since it does not have a regular diameter, therefore its thickness cannot be determined as a wire, etc.
Where it turns out that it can only be based on length and weight.
The classification of the fibers are in two groups:
- Constant Weight System
- Constant Length System
When it is necessary to refer to the thickness of a yarn or thread it is clear that it is difficult measuring it due to the small size and by the irregularity due to the twisting and tension of the yarn especially in the natural fibers.
An indirect system of expressing thickness was then used and the concept of numbering and title arose.
In spinning systems there are several forms of holder or numbering of yarns whether the source material is cotton, wool or synthetic.
There are several methods for numbering threads. The coexistence of all of them is due to the inertia of the custom, since with some only of them would be sufficient.
Numbers that describe the characteristics of a thread are called the title, and must be preceded by the technique that was used.
Numbering systems are classified into two groups well differentiated by their opposing approaches: Direct Systems and Reverse Systems.