GAS AND REFRIGERANT ASSISTED INJECTION MOULDING PROCESS

Assisted Injection Moulding (AIM) is part of a family of technologies that are conducted with plastic processing methods to improve product quality and significantly reduce costs. These technologies include the injection of gas or water, at high pressure, into the molten polymer within the injection mould. This process cores out sections of the part, and leaves hollow areas. The fluid-assisted injection moulding technology, which includes gas-assisted moulding and water-assisted moulding, has been used widely to manufacture plastic parts in recent years, due to the achievement of lightweight products, the relatively low resin cost per part, the fast cycle time, the uniform distribution of the packing pressure and the elimination of sink marks. Gasassist and water-assist technology may also be combined in sequence to achieve other benefits in certain applications. The basic idea of the proposed process is that the evaporation of a small quantity of water leads to a notable decrease in the cooling time and an increase in the dimensional tolerance of the injected part. Even though several patents pertaining to the use of gas and a refrigerant to obtain a hollow component exist, there is still a lack of knowledge regarding the effectiveness of the process. The present research has evaluated the effect of a co-injection of micro quantitates of water together with nitrogen.