Gas Assist injection moulding technologies
The gas assist injection moulding theories:
- After mould closing, the plastic is injected to fill or nearly fill the mould cavity.
- After a selected time delay, first phase is gas injected.
- Second phase gas penetration to compensate for volumetric shrinkage of the plastic as it cools.
- A uniform gas pressure is applied throughout the plastic.
- Gas is exhausted to atmosphere or for recovery before mould opens.
- Plastic refill commences after the nozzle valve is closed or after the plastic feed gate has solidified.
Gas Assist injection moulding typical applications:
- The gas flows into the path of least resistance in the thicker sections where the plastic interior is still in a molten state.
- Gas Assist injection moulding is normally applicable for components in which there are thick and thin sections.
Gas Assist injection moulding advantages
- Elimination of sink marks.
- Avoidance of plastic packing from the moulding machine.
- Reduced in-mould pressures by up to 60%, and therefore reduced press lock forces enabling larger
- The use of the gas injection moulding as a means of transmitting pressure uniformly throughout the moulding.
- mouldings on much smaller machines.
- Reduced power consumption.
- Reduced moulded in stress, and therefore improved dimensional stability with no distortion.
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