Injection molding filling is insufficient, how to improve the process?

The problem of insufficient filling in injection molding can be caused by a variety of factors, such as improper feed regulation, low injection pressure, slow injection speed, low injection mold temperature, low resin temperature, short injection time and so on. The following are some processes that can improve the underfilling of injection molding:

1. Improper feeding adjustment, lack of materials or multiple materials.

Feeding measurement is not allowed or feeding control system operation is not normal, injection molding machine or injection mold or operating conditions lead to abnormal injection cycle, preplastic back pressure is small or the cylinder of the small density of the material may cause the shortage of material, For large particles, void and large crystallizability of the specific volume change of the plastic such as polyethylene, polypropylene, nylon, and large viscosity of the plastic such as ABS should be adjusted higher amount of material, material temperature is high should be adjusted to increase the amount of material.

2. The injection pressure is too low, the injection time is short, and the plunger or screw is returned too early.

Molten plastic at low working temperature viscosity is higher, poor liquidity, should be injected with greater pressure and speed. For example, in the manufacture of ABS color parts, the high temperature intolerance of colorant limits the heating temperature of the barrel, which needs to be made up by higher injection pressure and longer injection time than usual.

3. Slow injection speed.

Injection speed has a very prominent significance for some products with complex shape, large thickness change and long process, as well as plastics with large viscosity, such as toughened ABS. When the product cannot be filled with high pressure, high-speed injection should be considered to overcome the problem of insufficient injection.

4. Material temperature is too low.

Because of the low temperature at the front end of the barrel, the viscosity of the molten material entering the cavity rises prematurely to the point that it is difficult to flow due to the cooling effect of the injection mold, which hinders the filling of the far end. The low temperature at the back of the barrel and the difficulty in the flow of the viscous plastic prevents the screw from moving forward. As a result, the pressure gauge appears to indicate sufficient pressure when in fact the molten material is entering the cavity at low pressure and low speed.

In order to improve the problem of insufficient filling of injection molding, it is necessary to check and adjust the process parameters comprehensively to ensure that the quality and performance of products meet the requirements. In the actual production, we also need to adjust flexibly according to the specific situation, in order to obtain the best molding effect. At the same time, we also need to continue to learn and master the new process technology and equipment operation methods, in order to improve their work ability and technical level.