What causes the problem of insufficient filling of the injection molding machine

    When the user friends use the injection molding machine to stop the injection operation, sometimes they encounter some problems, but they don't know how to deal with it, and they are often unable to do anything. Among the problems presented by the injection molding machine, there is a lack of filling, which means that the molten material is condensed without being filled completely after entering the mold, resulting in a lack of material in the product. There are several reasons for this kind of problem. The following injection molding machine manufacturers will take you to understand the reasons for the lack of filling in the injection molding machine.

    Excessive smoothing agent

    If there are too many smooth dosages in the raw material formula, and the wear gap between the non-return ring of the injection screw and the barrel is large, the serious reflux of the molten material in the barrel will cause the lack of supply and cause underfilling. In this regard, the amount of smoothing agent should be reduced and the gap between the barrel, the injection screw and the non-return ring should be adjusted, and the equipment should be repaired.

    Cold material impurities block the forehearth

    When impurities in the melt block the nozzle or the cold material is blocked.

    When gate and runner, the nozzle should be folded down to clear or expand the mold cold slug and runner cross-section. The gating system design is unreasonable. When a mold has multiple cavities, the unreasonable design of the gate and runner often leads to defects in the appearance of the plastic part. . When designing the gating system, pay attention to the balance of the gate. The weight of the plastic parts in each cavity should be proportional to the size of the gate, so that each cavity can be filled at the same time. The gate location should be selected at a thick wall, or a runner can be used. A balanced design plan. If the gate or runner is small, thin, and long, the pressure of the melt will lose too much along the way during the movement, the movement will be blocked, and poor filling will easily occur. In this regard, the runner cross-section and gate area should be expanded, and multi-point feeding can be used if necessary.

    Poor mold exhaust

     When the large amount of gas remaining in the mold of the injection molding machine manufacturer due to poor exhaust is squeezed by the flow material, and a high pressure greater than the injection pressure is generated, it will prevent the melt from filling the cavity and forming a short injection. In this regard, check whether there is a cold slug hole or whether its position is correct. For a mold with a deep cavity, an exhaust groove or an exhaust hole should be added at the undershot position.

     On the clamping surface, an exhaust slot with a depth of 0.02~0.04mm and a width of 5~10mm can be opened, and the exhaust hole should be set at the bottom of the cavity. When using raw materials with excessive moisture and volatile content, a large amount of gas will also be generated, resulting in poor mold exhaust. At this time, the raw materials should stop drying and eliminate the volatile matter.