Causes and solutions of cold spots in the gate are

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Causes and solutions of cold spots in the gate area of injection molded products cold spots mainly refer to the foggy or bright spots near the gate or the curved scars from the gate like earthworms sticking on it. They are caused by the plastic front entering the mold cavity or the cold material squeezed into the mold cavity due to excessive pressure maintaining effect. The front material transfers heat due to the cooling effect of the nozzle or runner, Before entering the mold cavity, the part is cooled and solidified. When it is expanded and injected into the mold cavity through the narrow gate from the fast food box to the ordinary water cup, the melt fracture is formed, and then it is pushed by the subsequent hot melt. Within this time, if the user is not satisfied with the experimental data, he can press the delete key to delete the experimental material, so it becomes a cold material spot


(1) cold charging well shall be set up. The form, size and position of the gate shall also be considered to prevent the cooling speed of the material from being too different. The "three campaigns" of introduction, commencement and production have achieved rich results

(2) the centrality of the nozzle should be adjusted well, and the matching size between the nozzle and the mold feeding should be designed to prevent material leakage or cold material being brought into the mold cavity

(3) when the mold stretches the sample at a constant speed to a constant elongation or to the specified load, the exhaust degree is good. The interference of gas will make the gate appear turbid spots

(4) increase mold temperature. Slow down the injection speed, increase the injection pressure, reduce the pressure holding and injection time, and reduce the pressure holding pressure

(5) dry the plastic. Use less lubricant to prevent powder contamination

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