Melt glue usually flows from the nozzle into the nozzle, but in some Laboratory Plastic Ware Mould, the nozzle is part of the laboratory plastic ware mould because it extends to the bottom of the laboratory plastic ware mould. There are also two main types of nozzles: open nozzles and closed nozzles. In injection laboratory plastic ware moulding production, open nozzles should be used more because they are cheap and have less possibility of retention.
If the injection laboratory plastic ware moulding machine is equipped with a depressurization device, this nozzle can be used even for low viscosity melts. Sometimes a closed nozzle must be used. This nozzle acts as a stop valve to block the plastic in the injection cylinder. Make sure that the nozzle is correctly connected to the nozzle sleeve, and the top hole is slightly smaller than the nozzle sleeve, which makes the nozzle easier to withdraw from the laboratory plastic ware mould.
2. Filter and combined nozzle
Impurities in the plastic can be removed by the 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 narrows and gaps can remove impurities and improve the mixing of plastics. Therefore, to extend it, a fixed mixer can be used to achieve a better mixing effect. These devices can be installed between the injection cylinder and the nozzle to separate and remix the melt. Most of them make the melt flow through the stainless steel channel.
Some plastics need to be vented in the injection cylinder during injection to allow the gas to escape. In most cases, these gases are just air, but it may be molten moisture or single-molecule gases. If these gases cannot be released, the gas will be compressed by the melt and carried into the laboratory plastic ware mould, it will expand and form bubbles in the product. To get rid of the gas before it reaches the nozzle or laboratory plastic ware mould, reduce or reduce the diameter of the screw root to depressurize the melt in the injection cylinder.
Here, the gas can be discharged from the holes or holes in the shooting cylinder. Then the diameter of the screw root is increased, and the melted glue of the devolatile matter is adapted to the nozzle. Injection laboratory plastic ware moulding machines equipped with this facility are called exhaust injection laboratory plastic ware moulding machines. Above the exhaust injection laboratory plastic ware moulding machine, there should be a good fume exhauster with a Three Way Stopcock to remove potentially harmful gases.