| The hot molding technology of the nonwoven fabric is one of the most common forming methods. By the nonwoven fabric hot molding, the products with different shape can be molded rapidly and efficiently to meet different enterprises’ requirements. In the process of the nonwoven fabric hot molding, the quality of molded product depends on the control of molding parameters. At present, the enterprises usually adjust the molding parameters by experience to get the better molded products. However, in the process of hot molding, the influence of mould and the molding parameters are not researched deeply yet.Entrusted by Suzhou meishanzi Garments Co., Ltd, the mould and molding technology of the nonwoven fabric hot molding were researched in this paper. Aimed at the problems that it is difficult for enterprises to accurately grasp the hot molding parameters and to overcome the difficulty of the nonlinear scale-space fabric forming, the mould and molding technology were researched by the finite element simulation with ANSYS14.0, meanwhile, the structure of hot plate was optimized. The main contents of this paper are as follows:(1) Firstly, the research status of the nonwoven fabric hot molding and its molding technology were discussed in this paper. The main contents and research area of this paper were determined.(2) The hot molding process and influencing factors of flexible PU foams are introduced. In the process of the nonwoven fabric hot molding, the heat transfer process of mould and the thermal stress caused by thermal deformation of hot plate were analyzed.(3) The orthogonal experiment was adopted to analyze the molding temperature, molding time and molding pressure in the hot molding process of bra mold cup. The depth difference of cup before washing, the depth difference of cup after washing and the compression rate of bra mold cup were set as assessment indexes to assess the performance of bra mold cup. And then, it is clear that what the most observable influencing factor of mould is.(4) The temperature variation on mould surface and interior of flexible PU foams were measured by multi-channel temperature teater-AT4516, and the thermal analysis of mould was done with ANSYS14.0. By experiments and analyses, the conclusion that the temperature on interior of flexible PU foams varies with its space size and nonlinear structure was obtained, the temperatures on interior of flexible PU foams and its corresponding positions on mould surface are different. The calculation formula calculating the molding temperature of flexible PU foams with different thickness was established.(5) With temperature tester, the temperature of hot plate was tested practically. The 3D drawing of hot plate was drew in SolidWorks and imported into ANSYS14.0 for thermal analysis, thus, the temperature field on the hot plate surface can be obtained. The deformations on several positions of hot plate were measured by changing the assembly between dial indicator and the marble platform, then the thermal deformation on different positions of hot plate were obtained by the thermal stress analysis of hot plate with ANSYS14.0, at last, the structure of hot plate was optimized. The warping problem caused by thermal deformation of hot plate was improved, thus the contact area between hot plate and bottom of mold can be increased, which makes the temperature on bottom of mold more homogeneous.By the simulation, analysis and experiments of mould and molding technology of the nonwoven fabric, it can be obtained that molding temperature is the most observable factor influencing the process of hot molding, and the temperature distribution of mould was also studied. The problem that the molding temperature needs to be adjusted repeatedly by experience was solved. Based on the thermal deformation of hot plate, the structure of hot plate was optimized,and the applicability of structure optimization was verified by experiments. Eventually, the hot plate after being optimized can works well in practical production. |
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