Research And Experiment Of Partial Mould Thermal Field Analysis Based On Induction Heating

The research mainly focused on the effect brought by partially induction heating device to eliminate defects of plastic product (such as short shot,weld line,rough surface,etc.). The electromagnetic induction heating process generates heat by means of Joule effect resulting from an eddy current,it is wildly used in industry because of its characters: fast heating,high energy transferring efficiency,high controlling precision,less pollution,etc. The most important problems in this research are: how to design heating device to produce partly and uniformly high temperature and how to set heating parameters to make good effect of injection defects eliminating. The experiments held in the last part of the research are tests of the capability of heating device. In this program,using ANSYS numerical simulation to solve the coupled thermal and electromagnetic fields problem and using MOLDFLOW injection simulation to establish injection parameters are smart way to avoid waste of time and energy in this part of research. So numerical simulating should be the most crucial technology in this paper.From the weld line classification and its forming principle, found that the basic factor affecting weld line forming should be flowing properties. Quoted Arrhenius viscosity model, analyzed the influence that mould temperature did to flow viscosity. Based on induction heating method, established the quick heating strategy. From filling simulation based on MOLDFLOW software, proved the effect that mold temperature raising did to melt front. From the aspects of molecule energy and energy equality theory, proved the importance mould temperature means to plastic viscosity. Considering surface effect of induction heating,designed a special induction heating group device.Based on induction heating theory and coupled field FEM analysis,constructed electromagnetic field and thermal field module. Discussed the solution to field coupling problem ,also discussed dependency of temperature to mould material properties. Found out temperature distribution and the law of temperature change depends on heating time. Analyzed the influence and importance that electricity frequency, electricity intensity through induction circle and distance between circle and mould to mould temperature controlling.Introduced MOLDFLOW model to filling simulation and primarily establish the injecting parameters. By series of injection experiments based on mould temperature control, proved the eliminating effect to injection defects brought by mould temperature rising. The experiments partied into short shot testing, weld line testing and surface smooth testing. Also in the last part of experiment, tested the mechanical performance (breaking force) by pulling machine and tested the products'surface smooth by professional device. All experiment proved the improvement of injection defects that brought by induction heating device.One more part of research in mechanical design of heating device is optimization. By discussing the shortages of the designed induction heating group and its inconvenience in practical usage, found the way to improve the device. For all the problems that shall face in future research are also discussed in the final chapter.