Mainstream road
It is a section of the mold that connects the nozzle of the injection machine to the runner or cavity. The top of the main flow channel is concave for engagement with the nozzle. The main channel inlet diameter should be slightly larger than the nozzle diameter (O.8mm) to avoid spiking and prevent the two from being blocked due to inaccurate convergence. The diameter of the inlet depends on the size of the product, usually 4-8mm. The diameter of the main flow path should be expanded inwards at an angle of 3° to 5° in order to facilitate the mold release principle of the injection molding die for the flow channel.
It is a hole located at the end of the main channel to trap the cold material produced between the two shots at the tip of the nozzle, thereby preventing the clogging of the runner or the gate. If the cold material is mixed into the cavity, the internal stress is likely to occur in the manufactured product. The cold material hole has a diameter of about 8 to 10 mm and a depth of 6 mm. In order to facilitate demoulding, the bottom is often borne by the stripper. The top of the stripping bar should be designed as a zigzag hook or a depressed groove so that the strip can be smoothly pulled out during demoulding.
Split channel
It is the channel connecting the main channel and each cavity in the multi-slot die. In order to make the molten material fill the cavity at equal speed, the arrangement of the runners on the mold should be symmetrical and equidistantly distributed. Injection Mold Principles The principle of the injection mold is from http://www.gkstk.com/article/wk-78500000722022 .html, reproduced please keep this link! . The shape and size of the runner section affect the flow of the plastic melt, the release of the product and the ease of mold making. If an equal amount of flow is used, the flow path resistance with a circular cross section is minimized. However, due to the small surface area of the cylindrical flow channel, the cooling of the diversion channel material is unfavorable, and the diversion channel must be opened on the two mold halves, which is labor-intensive and easy to align. Therefore, trapezoidal or semi-circular cross-section runners are often used, and they are opened on half of the mold with a stripper rod. The runner surface must be polished to reduce the flow resistance to provide a faster filling rate. The size of the runner depends on the type of plastic, the size and thickness of the product. For most thermoplastics, the cross-sectional width of the runner is not more than 8m, extra large 10-12m, extra small 2-3m. To meet the needs of the premise should minimize cross-sectional area, so as not to increase the shunt material and extend the cooling time.