Research On Heat Molding Of Non-woven Fabric Based On Mold Of Variable Temperature

Non-woven fabric is one kind of fabric which does not need to textile fabric to form.The ways of machinery,hot sticking and chemistry are applied to manufacture fabric.Non-woven fabric possesses excellent softness,gas permeability,planar structure and durability.Heat molding is one kind of the process which can make non-woven fabric be molded through single-pressing.Above all,its production efficiency is higher than other molding processes.Because of non-woven fabric more smooth and more rounded through heat molding,this way is widely used in the produce.As regard to traditional heat molding of non-woven fabric,it can’t ensure that non-woven fabric keeps affirmative temperature in the heat molding procedure,so non-woven fabric will appear some different phenomenons,such as color changing yellow,volume becoming big or small,camber not enough and so on.This paper cooperates with Suzhou Meishanzi Garments Co.,Ltd together.The heating system of the mold of variable temperature will be researched,and heat molding process of the flexible PU foam will be analyzed and discussed.According to the curved changes of space size and nonlinear temperature of the cup in the heat molding procedure and the weakness of traditional molding equipment etc,ANSYS will be used to simulate and analyze the temperature field of variable mold.The structure of variable mold and heating system will also be optimized and researched at the same time.The main contents of research and analysis are as follows:(1)The process element of heat molding of non-woven fabric will be discussed and analyzed.According to the features of the flexible PU foam having good gas permeability and a lot of holes,the structure of the variable mold and the heating system of variable mold will be optimized and designed again.(2)The capabilities and constitutive relations of the flexible PU foam will be researched and analyzed mainly.Then constitutive relations of the flexible PU foam will be researched and analyzed in machining and molding procedures.It is ultimate that constitutive relations are derived among viscoelasticity,velocity and stress tensor.The theoretical basis is provided with molding process of the flexible PU foam.(3)Firstly,hot theories of finite element are discussed and analyzed in the heat molding of the non-woven fabric.The temperature field of variable mold will be simulated and analyzed in this chapter.Then the tested equipment of multiway temperature will be adopted to check temperature of the mold and compare with temperature of the ANSYS simulating.The heat-transfer efficiency of the whole heating system and heating time of variable mold needed are ensured finally.(4)The cup depth difference and compression ratio will be compared before improving heating system and after improving heating system mainly in the chapter.The thick equipment modified is used to measure and analyze non-woven fabric after heat molding.The changes of fabric thickness are educed in the different temperature situation and experiment results analyzed.The heat-transfer efficiency of whole heating system is obtained through optimizing the structure of mold and simulating the temperature field of the mold in this paper.According to the features of the flexible PU foam having good gas permeability,the heating way of controllable hot winds is adopted to heat upper and lower molds based on primary electrical bars heated.Not only uneven problems of the molds heated are solved through experiment verified in heat molding procedure of non-woven fabric,but also the camber and softness of non-woven fabric are improved at the same time.The influence factor of cup depth difference and compression ratio are confirmed,including the temperature of hot winds and heat molding,the time of upper mold and lower mold closed.The range way of orthogonal experiment is used to confirm that the temperature of heat molding is the largest influence element of non-woven fabric.At last,the variance way of orthogonal experiment is adopted to make sure the best process level of heat molding.It is applied to effective production in the enterprises finally.