In order to prevent plastic from flowing out of the noz […]
In order to prevent plastic from flowing out of the nozzle, a decompression (rewinding) device or a special shooting nozzle is also installed. If you use a stop-flow production and supply, you must check it regularly because it is an important part of the shooting tank. At present, switch-type nozzles are not commonly used because the nozzles are prone to leak plastic and break down. At present, each type of plastic has a suitable type of nozzle.
Many injection moulding machines are equipped with screw retracting or suckback devices. When the screw rotation is stopped, it is withdrawn by hydraulic pressure to suck back the plastic of the nozzle. This device allows the use of an open nozzle. The number of suckbacks may be reduced because entering the air can cause problems for some plastics.
In most injection moulding cycles, it is necessary to adjust the amount of rotation of the screw village, so that when the screw is injected, most of the soft plastic will be left, which ensures that the screw reaches an effective advancement time and maintains a fixed firing pressure. The size of the small injection moulding machine is about 3mm; the size of the large injection moulding machine is 9mm. No matter how much screw padding value you use, it must remain the same. The size of the screw pad can now be controlled within 0.11 mm.