Basic explanation & schematic view - injection moulding process
The injection moulding process involves heating & injecting plastic material under pressure into a closed 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.
	injection 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.
	injection 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.
	injection 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 injection moulding process
	injection 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 injection moulding process starts again at 1.
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