AN INVESTIGATION ON AIR AND THERMAL TRANSMISSION THROUGH KNITTED FABRIC STRUCTURES USING THE TAGUCHI METHOD Anindya Ghosh 1 , Prithwiraj Mal 2 , Abhijit Majumdar 3 , and Debamalya Banerjee 4 1 Department of Textile Technology, Government College of Engineering and Textile Technology, Berhampore 742101, India 2 Department of Textile Design, National Institute of Fashion Technology, Hyderabad – 500081, India, Email: prithwiraj_iitd@yahoo.co.uk 3 Department of Textile Technology, Indian Institute of Technology, New Delhi 110016, India 4 Department of Production Engineering, Jadavpur University, Kolkata 700032, India 1. Introduction The comfort of a fabric is characterized by several properties such as transmission of heat, water vapor and air, warm or cool feeling on touch, absorbency, and wicking. Knitted fabrics are well known for their excellent comfort properties that are facilitated by the porous structure. Air can easily pass through the interyarn pores of knitted fabrics. On the other hand, knitted fabrics can hold lot of air within the structure resulting in lower thermal conductivity and higher thermal resistance than an equivalent woven fabric. In tropical and subtropical countries, high air permeability and thermal conductivity is required, whereas for winter, low air permeability along with high thermal resistance is desired. These comfort properties are decisively infuenced by the material (type of fber, yarn linear density, etc.), structural (loop length), and process parameters (carriage speed and yarn input tension). Process parameters can actually infuence the structural parameters and thereby infuence the comfort properties. Therefore, it is important to understand the roles of materials and process parameters affecting the comfort properties. Many researchers have studied the effect of raw materials and knitted fabric construction parameters on the comfort behavior of fabrics. Investigations revealed that the type of fber, fber blends, yarn structure and fneness, fabric structure, and different process parameters affect various comfort properties such as air permeability, moisture management, thermal conductivity, and thermal absorptivity [1-8]. Some attempts were also made by the researchers to predict and optimize different comfort properties of knitted fabrics using various techniques. Mavruz and Ogulata [9] tried to optimize air permeability of interlock knitted fabrics using different experimental designs. Fayala et al. [10] and Mitra et al. [11] predicted the thermal properties of knitted and woven fabrics, respectively, using artifcial neural network. Luo et al. [12] developed a fuzzy neural-network-based model to predict clothing thermal comfort. Cubric et al. [13] investigated on the signifcant fabric parameters affecting the heat transfer through porous structure and concluded that the thermal resistance of single jersey knitted fabric has a strong correlation with thickness, areal density, cover factor, and porosity. Most of the researches who worked on the comfort behavior of knitted fabrics are primarily concerned with the individual study of thermal properties or air permeability or moisture management. There is hardly any published literature that encompasses the individual as well as the interactive effect of material, structural, and process parameters on comfort properties, that is, air permeability, thermal conductivity, and thermal absorptivity. In this investigation, the Taguchi experimental design has been used to study the effects of material (yarn count), structural (loop length), and process parameters (carriage speed and yarn input tension) on air permeability, thermal conductivity, and thermal absorptivity for both single jersey and 1×1 rib knitted fabrics. Two noise parameters such as knitting position in the machine and yarn from different cones have been considered for both types of fabrics. 2. Experimental 2.1 Preparation of fabric samples One hundred percent cotton ring spun yarns of three different counts (such as 5, 7.5, and 10 Ne) were used to make both Abstract: Knitted fabrics have excellent comfort properties because of their typical porous structure. Different comfort properties of knitted fabrics such as air permeability, thermal absorptivity, and thermal conductivity depend on the properties of raw material and knitting parameters. In this paper, an investigation was done to observe the effect of yarn count, loop length, knitting speed, and yarn input tension in the presence of two uncontrollable noise factors on selected comfort properties of single jersey and 1×1 rib knitted fabrics using the Taguchi experimental design. The results show that yarn count and loop length have signifcant infuence on the thermo-physiological comfort properties of knitted fabrics. Keywords: Taguchi experimental design, air permeability, thermal conductivity, thermal absorptivity, single jersey, 1×1 rib knitted fabric. http://www.autexrj.com AUTEX Research Journal, Vol. 17, No 2, June 2017, DOI: 10.1515/aut-2016-0009 © AUTEX 152