he nozzle diameter is generally not processing of plastic products less than 4mm

The design of the entire pouring system must ensure that the flow of materials does not appear dead corners, and will not crosslink and solidify due to overheating. Next, I will analyze and analyze it for you. Now I will introduce the key points of its mold design. The larger value should be used when there is glass fiber filler.  2, runner structure design: the injection molding process and mold processing characteristics of the material must be considered when designing the pouring system.The last article introduced you to the thermosetting plastic runnerless injection molding technology. There must be good heat insulation measures between the runner plate and the template to prevent the temperature of the runner plate from rising, and the material in the runner is cross-linked and solidified, causing the runner to be blocked..

Mold design points:   1.  3, the runner plate should be made of materials with good stability and low expansion coefficient. Although the use of runnerless can reduce the loss of runner condensate and reduce the cost, due to the relatively complex structure of this type of mold, the price is usually 2 to 3 times higher than that of ordinary injection molds, so it is not suitable for the molding of small batch products. Economic analysis: Not all thermosetting plastics are suitable for runnerless injection molding, and the specific process should be considered. The general diameter is 6-8mm. The runner adopts a round cross section, which is conducive to the heat preservation and flow of the melt. In order to minimize the consumption of materials, the cross-sectional size of the runner can be designed to be smaller than that of the ordinary gating system, and the trapezoidal cross-section with smaller specific surface area or the circular or semi-circular cross-sectional runner can be selected.  9, the mold temperature must be accurately controlled and allowed to fluctuate within ±5°C.5-1°, which is convenient to pull out the sprue handle.  6, a parting surface should be provided on the runner plate, and a hook-type opening and closing plate should be equipped to prepare for the need to take out the solidified material from the runner plate. For example, during injection molding, because the material has a tendency to heat up, the mold is also heated, so there is no need to worry about the problem of heat dissipation due to the excessive surface area of ​​the runner.  4, the runner should have the same surface roughness as the cavity, and there should be no material retention.

The nozzle diameter is generally not processing of plastic products less than 4mm, with an inverted cone of 0. The temperature of the runner plate and each nozzle should be controlled separately.  7, the volume of the runner should be smaller than the total volume of the plastic injected at one time to prevent the plastic melt from staying in the runner for too long and losing fluidity. When using runnerless molding, due to the use of larger injection pressure and faster injection speed, and the temperature control of the gating system and mold cavity must be carried out at the same time, therefore, not only the injection molding machine should have greater power, but also the mold The heating power should also be 20%-30% higher than that of ordinary molds. The isolation method can be selected according to the situation of air insulation and insulation material insulation

Default Asked on October 28, 2020 in Advice.
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