Study On Mold-filling Flow And Technique Of Microcelluar Foam Injection Molding

An innovative technology, microcelluar foam injection molding process which have some virtue contrasting with conventional process such as reducing production weight greatly, improving dimension stability, reducing production distortion etc, in addition, do not need higher injection pressure for requirement of injection machine and can lower clamp tonnage, especially eliminate the pack and hold phase is studied. So far, there is few reported work for the mechanism of microcellular foam injection molding process, so it seems extremely important to do some research about it. This paper mainly includes these aspects as below:1. In this paper, the polymer melt flow in rectangle sheet mould and bubble growth have been studied by means of having microcosmic two phase liquid as macroscopical single phase liquid and appling the bubble cell model and mathematical model based on the basic equations of hydrodynamics. Finite Element software MPI is used for the numerical simulation of microcellular foam injection molding process.2. Have analysed the difference between microcellular foam injection molding process and conventional process, mainly involves: injection time, velocity field, temperature field, pressure field of the melt; have studied the variety trend and rule of the pressure in bubble, the bubble radius and its distribution for microcellular foam injection molding process; N2 has been compared with CO₂ as vesicant for melt fluidness, bubble radius and its distribution. All research results have been analysed from theory essence.3. Single factor method has been used for studing the relationship between the final bubble radius and its effect factors, conclusions have been drawn. The cause why the conclusions can be drawn has been analysed based on the mechanism.