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What is the cause of silver line marks in plastic mold products

Update:26-10-2019
Summary:

Silver line marks refer to the appearance of long needl […]

Silver line marks refer to the appearance of long needle-like white, frost-like fine lines on the exterior of the product. These fine lines often form a “V” shape with the tip facing away from the gate. As shown in the following figure, the common way of silver line marks is The acicular silver-white stripe formed by the elongated air bubbles is divided into degraded silver filaments and water-vapor silver filaments, and various silver filaments are generated from the gas which is precipitated from the front end of the stream. The degraded silver wire is composed of a gas in which the melt is overheated and degraded, and the water vapor silver wire is formed by vaporization of water vapor contained in the material. Here are some specific improvements to different reasons:
Silver mold mark phenomenon of plastic mold products
The first reason is that the plastic mold cooling water channel leaks and the cooling water seeps into the cavity;
Improvement method: strictly prevent cavity leakage;
The second reason is that the planning of the plastic mold exhaust system is unreasonable;
Improvement method: improve the exhaust system;
The third reason is that the melt temperature is too high, which causes the plastic to degrade the gas;
Improved method: lower the melt temperature;
The fourth reason is that the pressure holding time is too long, and the gas accumulated during the attack;
Improvement method: shorten the pressure holding time;
The fifth reason is that the injection speed is too fast, and the local temperature of the melt will rise sharply, so that the melt degradation accelerates the gas with more attack;
Improvement method: properly reduce the injection speed;
Reason six, the material moisture content is too large;
Improvement method: pre-drying the material;
Reason seven, the release agent will also attack a small amount of volatile gases;
Improvement method: reduce the amount of release agent;

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