Research and Experiment of Partial Mould Thermal Field Analysis Based on Induction Heating
|School||Shanghai Jiaotong University|
|Course||Materials Processing Engineering|
|Keywords||Injection flaws Induction heating Skin effect MOLDFLOW filling simulation ANSYS numerical analysis Electromagnetic - thermal field coupling|
This paper studies the cavity temperature control to improve the common defects in the injection molding process. Wherein the temperature control of the mold cavity is completed by the electromagnetic induction heating device. Electromagnetic induction heating warming fast, high efficiency, precise control, less pollution, small thermal inertia characteristics, are widely used in industrial production. Focus in the subject: the design and manufacture of the heating apparatus, so that the heating performance of the local high temperature effect to achieve rapid and uniform and the unevenness of the mold cavity applies; Explore various heating parameters of the heating effect, as experiments parameter settings provide a theoretical basis; verify the effect of mold temperature control to improve defect injection experiment and other testing laboratories. In the course of the study, in order to avoid a large number of experiments seeking the ideal induction heating parameters and the injection molding process parameters set using ANSYS numerical simulation and finite element modeling and simulation of electromagnetic - thermal coupling explore the current frequency, density and other factors heating effect; MOLD FLOW injection molding filling simulation of injection molding process of seeking the ideal. Numerical simulation technology is of great significance for the system design and research of the subject. The rheological properties of the molding material is a reflection of its internal structure, is also an important factor affecting the quality of the injection molded parts, and occurs in a certain shear rate and shear stress. When the entangled state is destroyed in the melt polymer molecules, the molecular reorientation Ordering, the viscosity of the melt will drop, the filling resistance decreases, the fill velocity of the melt in the mold cavity in this case is faster, the better. A tired intuitive Arrhenius equation (Arrhenius) shows the influence of temperature on the melt viscosity of the plastic melt, in particular in the low shear rate stage, the enhancement of the melt temperature has a significant effect on the viscosity reduction. Visible increase the melt temperature to reduce the melt viscosity, may improve some of the defects of the injection molded parts. From the molecular view of energy and energy conservation law, the mold temperature to reduce the decline of the melt temperature has a positive impact. So this topic cavity temperature control factors, in order to achieve the injection defects to improve the purpose of the study has a good theoretical basis. The paper discusses the significance of the unique skin effect of the electromagnetic induction heating of the mold cavity surface shallow, and as a theoretical basis for the design and manufacture of the external modular induction heating coil. The combined coil of induction heating temperature variation, and to provide a basis for the local induction heating control of the final temperature. Explore the coupling of the electromagnetic field and the temperature field in the finite element simulation of induction heating and the physical parameters of the mold material on the key issues of the temperature dependence solution. As a platform to ANSYS finite element model of the electromagnetic field of a thermal coupling. Obtained by numerical simulation of the temperature distribution of the stepped surface of the mold cavity and the heating temperature variation over time. Simulate and analyze the impact of the frequency of the alternating current, the coil current density and the coil with the cavity distance control of mold surface temperature, and summarizes the role of these factors on the heating effect, and their role principle analyzed. This part of the study for sensing power parameters set to provide a basis for the experiment. Introduction of the target injection molded parts MOLDFLOW model, preliminary exploration by the series filling simulation of a single control mold temperature, mold temperature under the conditions of induction heating charge less filling process, the effects of defects in the weld line. While the MOLDFLOW the numerical simulation provides the basis for the injection molding process parameters set. In the local heating of the mold cavity by controlling the modular induction heating apparatus, for the multi-injection experiments, comparison of the experimental results. Improve its effectiveness and regularity of these injection mold temperature on charge less obvious weld marks and surface quality rough defects were obtained. Additionally, respectively, from the injection products under different mold temperature sampling conducted a test of the tensile tests and surface roughness obtained quantitative improve results further validate A Arrhenius (Arrhenius) theory.