Prediction of needle heating in an industrial sewing machine

In industrial sewing, needle heating is a key problem that limits the further increase of sewing speed, and hence the productivity. Heat is generated during the sewing process because of friction between the needle and the sewing thread as well as between the needle and the fabric. The high temperature of the needle affects the quality and productivity of the sewing. The problem of needle temperature rise due to friction heat generation is considered in this paper and a simple analytical model is developed to predict needle temperature. The predicted needle temperature is compared with the experimental results by the inserted thermocouple method. Some of the process parameters, used as input variables, were also measured experimentally and experimentally observed values of needle temperature were compared with the theoretical prediction. It was observed that the temperature of the needle increases significantly with the presence of the sewing thread. Both the theory and the experimental results show that the needle temperature increases linearly with the machine speed within the ranges studied.