Basic explanation & schematic view - plastic moulding process
The plastic moulding process involves heating & injecting plastic material under pressure into a metal mould tool. The molten plastic cools & hardens into the shape inside the mould tool, which then opens to allow the mouldings to be ejected or removed for inspection, delivery or secondary operations. The plastic moulding process consists of four distinct operations: stage 1 - melting the plastic granules until molten stage 2 - injection of the plastic material into the closed mould tool stage 3 - cooling the plastic material inside the closed mold stage 4 - opening the mould tool and ejecting the plastic moulding Please see below for schematic views of the four stages of the plastic moulding process.
	plastic moulding process - stage 1 Material granules from the hopper feed into the heated barrel & rotating screw. Material melted by heat, friction & shear force is forced through a check valve to the front by the rotating screw.
	plastic moulding process - stage 2 Having been moved backwards by the shot of material at the front , the screw is forced forward by a hydraulic ram. This action injects material into the mould cavity in the closed mould tool.
	plastic moulding process - stage 3 The tool is held closed under pressure until the plastic material cools & sets hard in the mould tool cavity. This is often the longest part of the plastic moulding process
	plastic moulding process - stage 4 The screw starts to move back for the next moulding. The tool then opens & the finished plastic part is ejected. The tool is closed and the plastic moulding process starts again at 1.
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