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Open nozzles should be used more in injection molding

Update:26 Jan 2019
Summary:

The melt usually flows from the nozzle into the nozzle, […]

The melt usually flows from the nozzle into the nozzle, but with some moulds, the nozzle is part of the mould because it extends to the bottom of the mould. There are two main types of nozzles: open shot nozzles and closed nozzles. In injection moulding, open nozzles should be used more because they are less expensive and less likely to stay. If the injection moulding machine is equipped with a depressurizing device, this nozzle can be used even with a lower viscosity melt.

Sometimes it is necessary to use a closed nozzle, which acts as a stop valve and blocks the plastic shade in the shot cylinder. Make sure the nozzle is properly inserted into the nozzle sleeve. The top hole is slightly smaller than the nozzle sleeve, which makes the nozzle easier to remove from the mould. The hole of the mouthpiece sleeve is 1mm larger than the mouth of the nozzle, that is, the radius of the nozzle is 0.5mm thinner than the radius of the nozzle sleeve.

The impurities of the plastic can be removed by a filter of the extensible nozzle, ie the melt and the plastic flow through a channel which is separated into narrow spaces by the insert. These narrow and gaps remove impurities and improve the mixing of plastics.

Therefore extending it, a fixed mixer can be used to achieve a better mixing effect. These devices can be installed between the shooting tank and the nozzle to separate and remix the melt, mostly to allow the melt to flow through the stainless steel channel.

https://www.solidcomould.com/