In the field of injection molding, the emergence of hot runner technology can be regarded as a revolution. It has realized automated high-speed injection molding, greatly saving labor and material costs and significantly improving production efficiency. The hot runner system, as the core of this technology, consists of several key components such as the hot tip, hot runner plate, heating elements, and temperature controller.
The hot tip plays a crucial role in the hot runner system. It is responsible for precisely delivering the plastic from the manifold into each cavity, thereby effectively reducing the injection pressure. Given the diversity of customer needs and the different characteristics of various plastics, there is a wide variety of hot tip specifications and models, and custom processing can also be carried out according to customers’ special requirements. In terms of heating methods, hot tips can be divided into internally heated hot tips and externally heated hot tips; in terms of structure, common types include pointed tips, through tips, and needle-valve tips.
Among them, the needle-valve type hot tip stands out among many types of hot tips with its advanced technology and has many significant advantages:
Perfect Appearance of Products
The needle-valve type hot tip does not leave any gate vestige on the product, and the gate area presents a smooth state. This characteristic greatly improves the appearance and quality of the product. Especially for some plastic products with extremely high appearance requirements, such as high-end electronic product shells and precision instrument panels, it can avoid affecting the overall aesthetics of the product due to gate marks and meet the quality requirements of the high-end market.
Higher Filling Efficiency
The needle-valve type hot tip can use a larger-diameter gate, which speeds up the cavity filling. During the injection process, a faster filling speed can further reduce the injection pressure and reduce product deformation caused by uneven pressure during the molding process. At the same time, a large-diameter gate helps the plastic melt enter the cavity more smoothly, improving the injection efficiency and shortening the production cycle.
Effective Prevention of Undesirable Phenomena
During the mold opening process, the needle-valve type hot tip can effectively prevent stringing and drooling phenomena. Stringing can leave plastic filaments on the mold surface, affecting the quality of the next injection; drooling can cause the plastic melt to drip from the gate, resulting in raw material waste and environmental pollution. Through its unique design, the needle-valve type hot tip can precisely control the flow of the plastic melt and avoid these problems, ensuring the smooth progress of production.
Prevention of Material Back-Suction
When the injection molding machine screw retracts, the needle-valve type hot tip can effectively prevent material back-suction from the cavity. Material back-suction may cause impurities to enter the mold, affecting the quality stability of the product. This advantage of the needle-valve type hot tip can ensure the cleanliness inside the mold and guarantee the production of high-quality products in each injection.
Reduction of Weld Lines
The needle-valve type hot tip can perform timed injection. By precisely controlling the injection time, it makes the flow of the plastic melt in the cavity more uniform, thereby reducing the weld lines of the product. Weld lines not only affect the appearance and quality of the product but may also reduce its mechanical properties. The timed injection function of the needle-valve type hot tip can effectively improve this problem and enhance the overall quality of the product.
In summary, the needle-valve type hot tip occupies an important position in the hot runner system with its unique advantages. With the continuous development of injection molding technology, the needle-valve type hot tip is expected to be widely used in more fields, providing strong support for the high-quality production of plastic products.
