FABRIC GEOMETRY

 

FABRIC GEOMETRY

Drape Property

Drape is the property of fabric which refers to the way in which it hangs down in folds under its own weight. It is the opposite characteristic of stiffness of fabric.

Concept of Similar Cloth

Fibre or raw materials of two cloths may be same but they can differ in other factors, such as-

v  The yarn count may be different.

v  The ratio of yarn count in warp and weft may differ

v  The ratio of yarn spacing may differ

v  The average of spacing may differ

v  The weave design may differ

v  The amount of twist in yarn may differ

If there is similarity in cover factor of two cloths but they differ in such points, they are called similar cloth.

Cover Factor

Cover is the degree of evenness of thread spacing. Good cover gives the effect of a uniform plane surface and it can not be obtained with hard twisted yarn. In case of woven fabric, cover factor is number that indicates the extent to which the area of a fabric is covered by warp and weft threads.

For any fabric, by introducing suitable numerical constants its evaluation can be made, in accordance with any system of counting. It is denoted by ‘K’.

Mathematically, K=d/s

                     So, K₁=d₁/s₁ and K₂=d₂/s₂ 

 

 Where, d₁= warp diameter, d₂ = weft diameter

               s₁ = warp spacing, s₂ = weft spacing

               K₁ = warp cover factor, K₂ = weft cover factor

Fabric cover factor = K₁+K₂-K₁K₂

Value of K₁K₂ is very small, so it can be ignored. So, fabric cover factor = K₁+K₂

Warp spacing, s₁=1/p₁ and Weft spacing, s₂=1/p₂ (Where, P=threads/cm)

 

The cover can be calculated in percentage as

In the Tex system, the product of threads per cm and the square root of linear density are called the cover factor.