Bale Management

Bale management: Testing, sorting & mixing bales according to properties of fibre for producing specific good quality yarn at minimum cost is called “Bale management”.

Hook’s Law

Statement: “the force needed to extend or compress a spring by some distance is proportional to that distance.” and this can be written as: 

F = -kx ..............................(1)

Where F is the force, x is the length of extension/compression and k is a constant of proportionality known as the spring constant which is usually given in N/m. The negative sign is to signify that the restoring force due to the spring is in the opposite direction to the force which caused the displacement. Pulling down on a spring will cause an extension of the spring downward, which will, in turn, result in an upward force due to the spring.

Poisson’s Ratio

When a sample of material is stretched in one direction it tends to get thinner in the lateral direction - and if a sample is compressed in one direction it tends to get thicker in the lateral direction. Poisson's ratio is defined as the ratio of the change in the width per unit width of a material, to the change in its length per unit length, as a result of strain. Or Poisson ratio is the ratio of transverse contraction (or expansion) strain to longitudinal extension strain in the direction of the stretching force. Or The ratio of the relative contraction strain (transverse, lateral or radial strain) normal to the applied load - to the relative extension strain (or axial strain) in the direction of the applied load.

Theory of continuous filament yarns extension

Yarns are extended or elongated under loading. Stress analysis based on assumptions of small deformations and fixed thread diameter or theory of continuous filament yarns extension have been explained as below.

What is Yarn Pull-out method?

Yarn pull-out measurements reveal information on the interactions among the yarns of the fabrics, mainly on the friction between yarns. In the yarn pull-out method, the fabric is held by fixed jaws on both sides. A certain number of yarns in the form of fringe on the upper part of the fabric are formed and compressed into the upper movable jaw. The yarns held by the moving jaw are pulled in the upward direction and thus angle change is observed in the yarns (weft) located in the perpendicular direction to the yarns (warp) drawn. This method can be applied in any pulling device, but a special apparatus is needed to secure the fabric from both sides.