An investigation into the influence of stitch length on dimensional stability of flat bed weft knitted fabrics at different relaxation treatments

Abstract

Wefts knitted fabrics are prone to change their dimensions during finishing process and customer usage. The effect of stitch length and relaxation treatments to the dimensional change of flatbed weft knitted single jersey fabrics is investigated in this research. Experimental work has been carried out to monitor the changes of geometrical parameters such as wales per unit length, courses per unit length, width wise and lengthwise dimensional changes, area dimensional changes and changes of relaxation constant of the flat bed weft knitted fabric. Three different stitch length categories (high, medium and low) are selected in this experiment. From each stitch length seven samples are produced. The measurements are taken off the machine state and after different relaxation treatments such as Dry Relaxed, Wet Relax and Finished relaxed for the purpose of monitoring the changes of the above parameters. The stitch length and relaxation condition highly affect to the dimensional change of the fabric. The increasing of fabric relaxation is lead to the increasing of fabric shrinkage in both lengthwise and width wise of low & medium stitch length fabric. When the stitch length is high, it is noticed that expansion of width and the shrinkage of length while relaxation. For the tight knitted flatbed single jersey fabrics, the loop shape factors are almost similar to the data given by previous researchers based on circular knitted single jersey fabrics. Recommend not to increase the stitch length beyond certain limits as the dimensional behaviour is not possible to predict then