The Development Of Sewing Thread Stretching Setting Winder & The Research Of Optimizing Technology Parameters

High strength sewing thread stretching and setting precision winding machine (hereinafter to be referred as "stretching and setting machine"). Whether the machine can operate normally, stably and efficiently, the keys are based on the structure of the stretching and setting machine, the performance of closed-loop control system, the optimum control of the technological parameters such as the setting temperature, winding speed and stretching ratio towards the mechanical properties (tensile strength) and thermal shrinkage performance (boiling water shrinkage) for polyester filament sewing threads with different linear density.In this paper we firstly summarize processing technologies of sewing threads at home and abroad and development situation of precision winding machine, and then developed the WSF618b-LS stretching and setting winding machine with Zhejiang Wanshifa Textile Machinery co., Ltd together. Moreover, we specifically focuses on the development of the design of the closed loop control system.Stretching ratio is a direct factor influencing the mechanical properties of sewing threads. According to the requirements of the intrinsic quality and external quality requirements towards sewing threads after stretching and setting, we begin to develop stretching and setting machine. Based on the analysis of sewing thread stretching processing model, we solve the primary stretching model by using simulink in software matlab; and then according to the actual condition, we deduce the secondary stretching model and make a conclusion of the relationship of the stretching ratio and sewing thread breaking strength.After building the models, we carry out the experiments toward the technological parameters (setting temperature, winding speed and stretching ratio). The results of the three experiments are: ①To sewing threads whose linear density below 1000D/3, when setting temperature is under 200 degrees, compared breaking strength with the original sewing threads, the damage rate ranging from 6% to 10%, breaking strength loss is relatively serious. Furthermore, the sewing threads are dry and have a small amount of hair silk. Under the condition of that the setting temperature is around 200 degrees, sewing thread breaking strength begin to stabilize, and the strength damage rate range is controlled between 3% and 6%.②On the condition of setting temperature is 200 degrees, when the velocity raises up from 150 m/min to 450 m/min, the average breaking strength of different linear density sewing threads after stretching is about 4% of the original sewing threads, the change of breaking strength is not as the change of winding speed. And as the velocity raises up to 400 m/min, sewing threads produce some hair silk, which will lower the quality of the sewing threads and easy to plug the needles. ③Under the premise of determining setting temperature and winding speed, for all kinds of linear density of high-strength polyester filament sewing threads whose linear density below 1000 D/3, we need to control breaking strength damage rate within 4%. Therefore, we need to choose the corresponding optimal setting ratio, propose the concrete optimization scheme of high-strength polyester filament sewing thread processing technology, and finally establish technological parameter list of the system.One of the two main parameters influencing sewing threads’ thermal shrinkage performance is the winding speed, we perform an experiment according to this and according to the results we can conclude:①To sewing threads with same linear density, as the speed increases gradually, boiling water shrinkage rate increased gradually; high strength polyester filament sewing threads whose linear density between 120D/3 to 840D/3, when the velocity raise up from 200 m/min to 450 m/min, boiling water shrinkage of sewing threads ranging from 3.43% to 6.77% changes to ranging from 4.32% to 6.69%;②When the speed raise up to 450 m/min, boiling water shrinkage of sewing threads with different intensity is tend to be around 6.7%. The overlarge winding speed will result in weak fiber structure and the sewing threads are also easy to break when stretching, the hair silk significantly increased and the thread strength drops. ③To high strength polyester filament sewing thread whose linear density below 1000 D/3, its winding speed should be set between 200 to 350 m/min according to different linear density.Combined the results of the experiments above with the full text, we can figure out that the optimal technological parameter configuration tables for manufacturing high strength polyester filament sewing thread whose linear density below 1000D/3.