Cause Analysis Of Cold Spot In Gate Area Of Injection Molded Products

2008/8/11 9:49:00 41797

Cold spot mainly refers to the patches near the gate with foggy or bright markings or from the gate, such as if the earthworm attaches to the curved scar, which is caused by the plastic forwards entering the cavity or the cold material which is squeezed into the cavity after excessive pressure retaining effect. The forward material is cooled by the cooling effect of the nozzle or the passage, and is cooled and solidified before entering the cavity. When the injection cavity is expanded through the narrow gate, the melt breaks up, and then is pushed by the later hot melt material, so it becomes a cold spot.

Resolvent:

(1) the cold well should be set up well.

We should also consider the form, size and location of the gate to prevent the cooling rate of the material from being very different.

(2) the center of the nozzle should be adjusted, and the matching dimensions of the nozzle and the mold feed should be well designed to prevent leakage or cause cold material to be brought into the cavity.

(3) the mold exhaust degree is good.

The interference of gas will make the gate appear cloudy markings.

(4) raise mold temperature.

Slow down injection speed, increase injection pressure, reduce pressure and injection time, and reduce pressure.

(5) dry plastic.

Use less lubricants to prevent powder contamination.