Knitting Force Measurement on Flat Knitting Machines

Knittability can be defined as the ability of yarns to run on knitting machines without problems. Knittability can be achieved when less stress is applied on the knitting machine parts by the knitting yarns. This paper presents a novel measuring system for the knitting force needed to perform knitting yarns on flat knitting machine based on data acquisition system (DAS). The proposed system is used to measure the knitting force at different machine settings and different properties of the knitting yarns to determine the optimal production conditions. For this reason, three types of knitted fabric structures (single jersey, Rib 1 × 1, and full cardigan) with three different loop lengths and five different twists of ply yarn were produced. The obtained results showed the optimal yarn ply twist factor which gave minimum knitting force (less stress on needles or knitting yarns) at different loop lengths for each structure. 1. Introduction In textile industry, there is mutually stress between materials and machine parts, such as traveler and spinning yarn on spinning machines, heald eyes and warp threads on weaving machines, and sewing needle and sewing thread, sewing needle and fabrics on sewing machines. In the knitting industry there is a stress between the needle hook and knitting yarn during withdrawal of the new loop and between stem, latch of the needle, and old loop during knock-over process. Consequently, the study of these stresses helps to design and manufacture each knitting needle and knitting machines parts. Also, it helps to determine knitting yarns specifications in order to preserve the parts of knitting machinery from damage for a longer period and keep the knitting yarns from breakages to avoid all of the defects and low production. The previous searches aimed to study knitting force theoretically and practically at different knitting variables such as the knitting machine settings (machine speed, type of needles, cam setting, input, and take-down tension), knitted fabric structures, and knitted yarn properties. Wray and Burns [1, 2] developed a transducer system to measure the dynamic forces between a latch needle and the stitch and guard cams during the formation of a knitted loop. D？nmez and Marmarali [3] recorded the number of machine stops, yarn breaks, and holes, for Rib 1 × 1 produced with thirty different yarns. They proved that two equations depending on yarn characteristics can be used to predict yarn-needle and yarn-yarn friction. Hu and Zhu [4] proposed a quantitative method used for assessing the degree of glass filament