| The mold temperature is the most direct factor of the melt’s filling flow, cooling rate and the quality of the plastic parts, at the same time, affects the critical process parameter of the molecular orientation of the material, weld lines, residual stress after molding, shrinkage, warping deformation. However, the temperature on mold cavity’s surface affects the melt’s filling flow and cooling in the process of numerical simulat-ion of injection molding; therefore, the calculation of the cavity’s surface temperatu-re will play an important role in results of numerical simulation of injection molding.At present, the people using the steady-state analysis calculated the average temperature of cavity surface, and then made directly it as the boundary conditions for the filling and packing analysis. But using the average temperature of cavity surface as boundary condition will cause some error for the heat transfer analysis; this error may affect analysis of the numerical simulation of precision plastic products or thin-walled parts. In numerical simulation analysis, Mainly due to the use of the cavity surface average temperature boundary makes initially calculated melt temperat-ure of products lower than the melt temperature of the cavity surface transient temp-erature field boundary, this makes condensing time of products of the average tempe-rature as the boundary condition shorter than condensing time of the cavity surface transient temperature field as the boundary condition. Molding thin-walled parts will especially increase flow resistance in the injection molding simulation analysis, this makes injection pressure of products of the average temperature as the boundary con-dition higher than injection pressure of the cavity surface transient temperature field as the boundary condition. In the end of injection molding, melt temperature of produ-cts of the average temperature as the boundary condition is a few higher than melt temperature of the cavity surface transient temperature field as the boundary conditi-on, so there will be some errors in the numerical simulation of packing process.Because the mold cooling analysis calculation is very time-consuming, it is very difficult to giving the instantaneous cavity surface temperature distribution. Thus this article on the basis of previous work, artificially constructed cavity surface transient temperature field by the average temperature of the mold cavity surface, simultaneou-sly using VC++language has compiled flow analysis calculation program to simulat-e cavity surface transient temperature field as boundary condition, then imported it into the Z-Mold software and analyzed the cavity surface temperature to influence of the numerical simulation of injection molding flow analysis, including:(1) Analyze the cavity surface temperature changes, in detail, which is influence on plastic molding. Elaborate mold temperature processing of traditional injection mo-lding numerical simulation and derive one-dimensional heat conduction equation wit-hout heat source by using the finite element-finite difference mixing, construct one-dimensional computational model to analyze the impact of mold temperature on the melt temperature.(2) Thoroughly analyze the injection mold process parameters to influence of the cavity surface transient temperature field, then construct the cavity surface transient temperature field through cavity surface average temperature and analyze its rational-ity and introduce quasi-transient temperature boundary of cavity surface to the Z-M-old software.(3) Respectively, to the average temperature of the cavity surface field and simul-ated cavity surface transient temperature field as boundary conditions, by using Z-Mold software analyze flow process of numerical simulation of the injection mold-ing and compare analytical results of numerical simulation. |
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