| Gas-Assisted Injection Molding (Gas-Assisted Injection Molding, GAIM) is a novel kind of plastic processing technology which is based on traditional injection molding. It has been applied widely now.The filling process of GAIM about two phases flow of gas and melting, penetration of gas, the former interface of melt and the boundary of molten-gas have been studied deeply by the scholars at home and abroad. Based on this, this paper studies the flow and control equations about two phases flow of melt and gas in cylindrical cavityand flat cavity, the gas-molten interface, the boundary conditions of hypothesis , boundary conditions of derivation and the standard of the gas-assisted injection molding design, runner design and mould design were summaried.The automobile tail door adorn plate is the research object of this article, was simulated by gas-assisted analysis module of Autodesk Moldflow/AMI/GAIM。Through setting different gating system plans,we can acquire the results about the effects of the position of gate and intake on the injection quality.The result shows that if the gate is far away from the intake's thin wall position,it can effectively avoid penetrating phenomenon. The process parameters's effects on injection percentag were analysed by orthogonal experiment method.The results show that: the influence of pre-injection quantity of the melt is biggest to the lengh of penetrating. lower than 80% , the melt will be penetrated.The shorter of delay time, the better of penetrate length. The gas pressure is biggest to the gas seepage's influence, The lower gas pressure can effectively prevent gas permeability. The higher of melt temperature, the more serious of air permeability in the intake.In the experiment process, the secondary development of Moldflow about airway length and orthogonal experiment is made to get the best technical parameters: 230 degrees of melt temperature,the best gas injection is 87%, the maximum pressure 6Mpa, the delay time of gas injection 0.5 s. |
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