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Injection molding is a tool for producing plastic products, and it is also a tool for giving plastic products complete structure and precise size. At the same time, injection moulding is a processing method used in mass production of some complex parts. Specifically speaking, melted plastics are injected into the cavity by high-pressure injection moulding machine. After cooling and solidification, the products are eventually formed. To have a more profound understanding of the injection molding, more details about the injection molding feed system will be given in the following.
It is a passage connecting the injector nozzle of injection molding machine to the shunt channel or cavity in the mould. The top of the main channel is concave to connect with the nozzle. The inlet diameter of the main passage should be slightly larger than that of the nozzle to avoid spills and to prevent blockage due to improper connection between the two part. Import diameter depends on the size of the product, which is generally 4-8 mm. The diameter of the main channel should be enlarged inward at an angle of 3 to 5 degrees so that the runner excrescence can demold.
It is a hole located at the end of the main channel to trap the cold material produced between the two injections at the end of the nozzle, so as to prevent the blockage of the branch channel or the sprue. If the cold material is mixed into the cavity, the internal stress will easily occur in the product. The diameter of the cold well in the injection molding feed system is about 8-10 mm and the depth is 6 mm. In order to facilitate demoulding, the bottom is usually assumed by the demoulding rod. The top of the demoulding rod should be designed as a zigzag hook or a sinking groove so as to pull out the bulge of the main channel smoothly when demoulding.
It is the channel connecting the main channel and each cavity in the multi-groove mold. In order to make the melt fill all the cavities at the same speed, the arrangement of the shunts on the plastic mould should be symmetrical and equidistant. The shape and size of the shunt section have an effect on the flow of plastic melt, the demoulding of products and the difficulty of die manufacturing. If the flow rate is equal, the resistance of the circular section is the smallest. However, because of the small specific surface of the cylindrical channel, it is not conducive to the cooling of the neoplasm of the branch runner, which is labor-intensive and difficult to align. Therefore, trapezoidal or semi-circular branch runners are often used in the injection molding, and they are arranged on half of the mold with a demoulding rod.
It is the channel connecting the main channel or the shunt channel with the cavity. The cross-sectional area of the channel can be equal to that of the main channel or the shunt channel, but it is usually smaller. So it is the smallest section in the injection molding feed system. Additionally, the shape and size of the sprue have a great influence on the quality of products.
In short, the injection molding feed system plays an important role in the injection molding because it is directly related to the forming quality and production efficiency of plastic products. That is all that counts.
