POM 100P American DuPont high toughness parts POM high stress parts

< Cold material spots mainly refer to the foggy or bright-colored spots near the gate of the part or the curved scars starting from the gate that look like earthworms attached to them. They are caused by the plastic entering the cavity or due to excessive It is caused by the cold material that is later squeezed into the mold cavity due to the pressure holding effect. The forward material transfers heat due to the cooling effect of the nozzle or runner, and is partially cooled and solidified before entering the mold cavity. When it passes through the narrow gate, it expands and is injected into the mold cavity. When the melt melt breaks, it is then pushed by the subsequent hot melt material, thus becoming a cold material spot.
Solution:

The cold material well must be opened. Also consider the size and position of the gate to prevent disparity in the cooling speed of the materials.

The center of the nozzle must be adjusted well, and the matching size of the nozzle and the mold feed must be designed to prevent material leakage or cold material from being brought into the cavity.

The mold is well vented. The interference of gas will cause turbidity patterns on the gate.

Increase mold temperature. Slow down the injection speed, increase the injection pressure, reduce the holding pressure and injection time, and reduce the holding pressure.

Dry plastic well. Use less lubricant to prevent powder from being contaminated.

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