Effect of Yarn Tension on Size Pick up and Strength of Warp Yarn

Review Article

Adv Res Text Eng. 2019; 4(2): 1040.

Effect of Yarn Tension on Size Pick up and Strength of Warp Yarn

Lami Amanuel*

Department of Textile Engineering, Wollo University - Kombolcha Institute of Technology, Africa

*Corresponding author: Lami Amanuel, Department of Textile Engineering, Wollo University - Kombolcha Institute of Technology, Ethiopia, Africa

Received: August 20, 2019; Accepted: September 10, 2019; Published: September 17, 2019


During sizing; the stretch in the wet & drying zone are totally responsible for loss in elongation which causes more breaks in sizing and the subsequent processes in weaving. If it is not properly controlled in sizing this parameter will considerably result in to reduction of yarn strength which will increase warp breakage rate and machine efficiency in the subsequent processes after sizing. This can be overcome by maintaining no stretch or negative stretch in wet zone between saw box zone & first drying cylinder. If the stretch in the zone does not control properly it will considerably increase the warp breaks at loom, it will ultimately result to reduce loom performance. This study investigated the weaving performance and physical properties of cotton yarn sized at high pressure squeezing. The size penetration, film properties, and the yarn packing density were studied in order to explain the performance of sized yarn. A change in breaking force, elongation at break and abrasion resistance by sizing depends on the sizing conditions, also on the yarn properties before sizing. In addition to the breaking force, which is very important in the weaving process, elongation at break and abrasion resistance etc. largely depend on the fibre and yarn properties, and on the conditions of processing the yarn in sizing. The greatest increase in breaking force by sizing is registered in finer yarns, but also the most level increase considering the samples of the same count. This investigation aims to stress the importance of optimizing size coat to achieve as high production as possible in weaving and product quality. It is emphasized that significance and complexity towards the standardization of sizing in order to produce high-grade yarns were very important.

Keywords: Polymeric carbohydrate consisting; Tensile tester


Sizing is the process of applying protective adhesive coating on the yarn surface. This is the most important segment of weaving preparatory process. Increase abrasion resistance and increases the weave-ability of the yarn. Proper sizing practices reduce end breakages at loom, which ultimately increases loom performance.

There are various sizing parameters, which are responsible for maintaining quality of size beam. The machine speed, squeezing roller pressure, viscosity of size paste, temperature of saw box and stretch control are the essential parameters, which need to be control during sizing. A size yarn must have good abrasion resistance, which clearly reflects by its increase tensile strength with minimum loss of elasticity and required amount of moisture for looming. Weavers beam should not have more number of missing ends, cross ends, lappers and taped ends so that it could unwind smoothly in weaving machine. To increase the strength in abrasion resistance of yarn after sizing depend on a number of factor, namely the recipe of the size mixing. Size preparation, level of size pickup and its degree of penetration into the yarn as well as on the sizing condition [1].

During sizing the warp sheet has to be kept under a certain minimum tension for ensuring proper contact of yarn with the drying cylinders, for easy splitting of the warp sheet at the lease rods and for preparing beams of the required density. The effect of stretch on the frequency distribution of elongation of sized yarn and the relationship between the stretch and the loss in yarn elongation during sizing has not been so well documented.

An attempt was made in this study to ascertain the effect of stretch during sizing on the elongation of sized yarn at break and the way in which it affects the performance of the yarn in weaving. An attempt was also made to correlate the stretch in sizing and the loss in yarn elongation during sizing. The other sizing variable which could influence the weave-ability of yarns. E.g. size liquor concentration, its viscosity and temperature, size add-on and machine speed, were kept constant as far as possible. Sized yarn samples were tested for tensile properties on a tensile strength tester.

Materials and Methods

The experiment was conducted on a sizing machine equipped with dry mechanism. The stretch during sizing was measured by using both stretch indicator and mechanical length counters. In each experiment sufficient beams was prepared from the same creel after adjusting the stretch before the start of each beam.

The other sizing variable which could influence the weave-ability of yarns like size liquor concentration ,viscosity and temperature, size add on and machine speed were kept constant as far as possible except the tension. Sized yarns were tested for tensile properties on a strength tester.

The materials used for this investigation were three 100% ring spun cotton yarns with count 34 tex. Size preparation of the yarn, sizing agents and the requirements of sizing process based on two recipes with different concentration were take

Preparation of yarn sample

In the sizing process all the conditions mentioned, which are necessary to achieve maximum sizing results were held constant, due to which it can be safely claimed that yarns were sized under the same conditions. Sizing was carried out using two recipes with a size concentration.

The conditions of sizing process were not varied by changing the recipe or size concentrations. The water temperature in the pre wetting box was 85°C and the size temperature was 90°C. The sizing speed was 40-50 m/min and the temperature on the cylinder of the contact dryer was 4 bar.

To test the sample before and after sizing, methods were used. Thus strength of yarn and elongation at break by single and double yarn tester. Process of this method is; before sizing sample was dried after which they were weighed and then sized, after the samples were dried again and weighed. The amount of size pick up is calculated using

Size pick up = sized yarn – unsized yarn/ unsized yarn*100

Result and Discussion

The following Tables and Figures explain the tensile behavior of sized and Un-sized cotton yarns which are selected for the production of Pillow case.