Cotton Fibres Characteristics Consider For Spinning Process
- Length
- Strength
- Fineness
- Maturity
- Cleanliness
- Elongation.
Fibre length:
Fibre length is one of the most important fibre characteristics.
It influences:
Spinning limit.
- Yarn strength.
- Yarn evenness.
- Handle of the product.
- Lusture of the product.
- Yarn hairiness.
- Productivity.
Different stable length of Cotton:
Short staple —- 1 inch Or Less.
Medium stable —- 1 1/32 inch to 1 1/8 inch.
Long stable —- 1 5/32 inch to 1 3/8 inch.
Extra long stable —- 1 13/32 inch to Above.
Fibre Fineness:
Fibre Fineness is one of the most important fibre characteristics. It determines how many fibre are present in the X-section of a yarn of given thickness.
Fineness is usually specified by the relation of mass (weight) to length (Km).
\Tex = mass/length
The Fineness scale is as follows:
MIC value Fineness
Up to 3.1 Very fine
3.1 to 3.9 Fine
4.0 to 4.9 Medium
5.0 to 5.9 Slightly Course
Above 6 Course
Strength:
The minimum strength for a textile fibre is approximately 6 CN/Tex. In relation to cotton the strength of fibre bundles is measured and stable as the pressley value.
\Pressley Index = Breaking strength in lbs / Bundle weight in gm.
Pressley Index Strength
93 – Above Excellent
87 – 92 Very strong
81 – 86 Strong
75 – 80 Medium
70 – 74 Fair
Under 70 Weak
Maturity:
Fibre maturity means the thickness of cell wall. The more thickness, the maturity. Unripe fibres have neither adequate strength nor adequate longitudinal stiffness.
They therefore lead to:
- Loss of yarn strength.
- Nippiness.
- A high proportion of short fibres.
- Varying dye ability.
- Processing difficulties mainly at the card.
Elongation:
It is a very important factor for spinning. Without this fibre could not be spinned. Elongation of cotton fibre 6-10%.
Cleanliness & Trash content:
Generally many types of foreign matter may contain in cotton stocks.
Vegetable matter Mineral matter Other foreign matters
- 1.Husk 1. Soil 1. Metal fragments
- 2.Seed 2. Sand 2. Cloth fragments
- 3.Stem 3. Dust 3. Packing fragments
- 4.Leaf fragments
- 5.Wood fragments
As spinning process is sensitive to impurities. So the fibre should be main taired clean as far as possible. The reason for fibre containing such foreign matters are:
Modern high performance plucking system
- Hard ginning, cleaning & pre-drying
- Cleanliness, handling, during transportation & pack.
The scale below represents the degree of contamination:
Up to 1.2% ——————— Very fine
1.2 to 2.0% ——————— Clean
2.0 to 4.0% ——————— Medium
4.0 to 7.0 % ———————- Dirty
7.0 to Above ———————- Very dirty
Effect of unclean fibre:
Additional stress on personal.
- Environment problem.
- Effect on the production.
- Stressing of the machine.
Brand Name Country
Pima, Arizona & SJV ———– USA
Eluna, Parvee & Ronda ———– CIS
Giza ———– Egypt
Andy ———– Australia
Suvin ———– India
Delta ———— Bangladesh
Barakat ———— Sudan