With the use of synthetic fabrics and threads in high speed sewing, needle heating due to friction between the needle and the fabric becomes a serious problem which limits further increase of the sewing speed. The high temperature in the needle can accelerate thread wear, cause wear at the needle eye, and damage the thread. It can also scorch the fabric, as well as temper and weaken the needle itself. Experimental methods, such as: infrared radiometry, infrared pyrometry, etc., have been applied to analyze this problem in previous studies. They revealed some important factors that affect the needle peak steady state temperature. In this study the numerical (FEA) model developed to simulate the needle heating is fine tuned and verified via infrared radiometry. The FEA model incorporates detailed needle geometry and the effects of thread on needle heating. It deals with a transient heat transfer process with time and position dependent boundary conditions. It correlates various important factors that affect the needle heating, such as needle characteristics, fabric properties, and sewing conditions to the needle temperature distribution. Given various needle geometries, sewing conditions, and fabric properties, the model can simulate the needle heating process, including the initial heating phase and the steady state. It can also predict the temperature distribution in the needle as well as the time to reach steady state. The trends of the simulation results correlate well with experiments.
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