The hot runner injection mold is also called a runnerless injection mold. The difference between its gating system and the ordinary gating system is that in the whole production process, the plastic in the gating system is always in a molten state, and the pressure loss during injection molding is small. Casting, multi-cavity molds and large plastic parts realize low pressure injection molding. In addition, this gating system has no gating system aggregate, enabling waste-free processing.
Due to the special process of the hot runner in the molding process, this type of injection molding method has the following characteristics.
①Saving materials, energy and labor. The condensate in the pouring system of ordinary injection molded parts accounts for a large proportion of the material consumption. The secondary utilization of the condensate is to reshape the plastic parts with fresh materials after crushing, extrusion, and dicing. The problem is that it is easy to bring in Foreign matter causes pollution, which reduces the performance of secondary molded plastic parts. Statistics show that the waste rate of plastic parts mixed with secondary recycled materials increases by about 5 times, and the material in the flow channel of thermosetting plastics will become completely waste after curing and cannot be reused. .
There are no runner aggregates in the hot runner injection mold, and for thermosetting plastics, this part of plastic consumption is less. Thermally explicit plastics eliminate the recycling of these aggregates, saving energy consumption and labor. The energy savings in long-term production are considerable.
②Improve the quality of plastic parts. In the hot runner mold, the plastic in the runner is always in a molten state, which makes the pressure distribution in the cavity more uniform. Reducing the melt temperature difference can avoid or improve fusion lines, shorten the holding time, reduce the stress of feeding materials, and minimize the gate marks.
③ Shorten the molding cycle. The injection molding cycle of plastic parts includes mold closing time, mold filling time, feeding time, cooling and solidification time, and demolding time. With hot runner mold, the time of each stage can be shortened.
④ Material saving, energy saving and labor saving. Generally speaking, the mold cost of the hot runner mold increases by about 10% to 20%, but this increase can be quickly compensated by the above-mentioned economic benefits. However, the structure of the hot runner injection mold is very complex; in particular, the temperature control requirements are strict, otherwise it is easy to decompose and scorch the plastic, and the manufacturing cost is high, which is not suitable for small batch production.
Post time: Feb-08-2022