injection moulding process - explanation & Video
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.
|A schematic view of the injection moulding process|
|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.
For more information, you can also watch our injection moulding video:
For more injection moulding advice, have a look at our plastic moulding advice pages.