The melt usually flows from the nozzle into the nozzle, but with some molds, the nozzle is part of the mold because it extends to the bottom of the mold. There are two main types of nozzles: open shot nozzles and closed nozzles. In injection molding, open nozzles should be used more because they are cheaper and less likely to stay. If the injection molding 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 mold. 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.
2. Filter and combined nozzle
The impurities of the plastic can be removed by a filter of the extensible nozzle, that is, the melt and the plastic flow through a channel which is divided into narrow spaces by the insert. These narrow and gaps remove impurities and improve the mixing of the plastic.
Therefore, it is possible to use a fixed mixer 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.