Problem:

Injection molding products are incomplete, how to overcome the process?

Answer:

Improper feed adjustment, lack of material or multiple material

Feeding measurement is not allowed or feeding control system operation is not normal, injection molding machine or mold or operating conditions limit resulting in abnormal injection cycle, pre-plastic back pressure is small or small particle density in the cylinder may cause the lack of material, For large particles, many voidage particles and crystallizability of large specific volume change of plastics such as polyethylene, polypropylene, nylon, etc. And large viscosity of plastics such as ABS should be adjusted to a higher amount of material, material temperature is high should be adjusted to a higher amount.

When there is too much material at the end of the barrel, the injection screw needs to consume more injection pressure to press and push the excess stock in the barrel, which greatly reduces the effective injection pressure of the plastic entering the mold cavity and makes it difficult to fill the product.

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

Molten plastic has higher viscosity and poor fluidity at a low working temperature, and should be injected with greater pressure and speed. For example, when making ABS color parts, the high temperature intolerance of the colorant limits the heating temperature of the barrel, which must be made up by a higher injection pressure and an extended injection time than usual.

Slow injection speed

Injection speed for some complex shapes, large changes in thickness, long process products, and large viscosity of plastics such as toughness ABS has a very prominent significance. When the use of high pressure can not fill the product, it should be considered to use high-speed injection to overcome the problem of injection dissatisfaction.

The material temperature is too low

The front end of the barrel is low, and the molten material entering the cavity rises prematurely to the point where it is difficult to flow due to the cooling effect of the mold, which hinders the filling of the far end; The low temperature at the back of the barrel and the plastic with large viscosity are difficult to flow, which hinders the forward movement of the screw, resulting in the appearance that the pressure displayed by the pressure gauge is enough and the molten material actually enters the mold cavity at low pressure and low speed.

Low nozzle temperature may be the fixed feeding nozzle for a long time with the cold mold contact lost heat, or the nozzle heating ring heating insufficient or poor contact caused by low material temperature, may block the mold feed channel; If the mold does not have a cold well, the self-locking nozzle is used. After the feeding procedure is adopted, the nozzle can maintain the necessary temperature; When the nozzle is too cold at the beginning of the machine, sometimes you can use the flame gun to do external heating to accelerate the nozzle temperature.

Plastic Industry Video