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Plastic mold product defective phenomenon caused by rubber problem

date：2023/08/19

Analysis of the causes of the residual phenomenon of plastic mold products caused by the rubber problem during the injection of the mold: the change in the supply of the rubber, the failure of the plasticizing ability, the insufficient plasticizing ability, the plasticizing time is too long, the lens is not transparent So wait.
The main reason for the change in the supply of rubber compounds is as follows:
1. The particle size of the compound varies;
2. The lubricity of the rubber is too good;
3. The temperature of the supply part of the feed rod is too high;
4. The speed of the screw is too fast;
5. The back pressure of the screw is too low;
6. The temperature of the compound is too low;

Second, the plasticizing ability of the rubber compound fails, the main reason analysis:
1. The plasticizing ability of the compound is too large;
2. The fluidity of the compound is insufficient;
3. The temperature of the compound is too high;
4. The screw is damaged;
The plasticizing ability of the rubber compound is not enough, the main reason analysis:
1. The fluidity of the compound is too high;
2. The speed of the screw is too slow;
3. The back pressure of the screw is too low;
4. The temperature of the compound is too low;
5. The plasticizing time of the compound is too long, the main reason analysis:
1. The fluidity of the compound is not enough;
2. The screw speed is too slow;
3. Improper screw design form;
4. The power of the screw rotating motor is small;
Fifth, plastic mold products-lens transparency is not good, the main reason analysis:
1. The temperature of the compound is too high or too low;
2. The injection speed is too slow;
3. The mold stability is too low, and the polishing of the mold is not good;
4. Due to the change in the cooling rate of the rubber compound, the transparency is different:
Poor transparency: due to poor contact between the melt and the mold surface, small concaves on the surface of the plastic parts cause light scattering or decomposition of the plastic parts, foreign matter impurities, or the mold surface is not bright, making the transparent plastic poor or uneven
The reasons for this phenomenon are as follows:
(1) Low mold temperature, low material temperature and poor contact between the melt and the mold surface;
(2) The surface of the mold is not shiny, there are oil stains and moisture;
(3) Too much or inappropriate release agent;
(4) The material temperature is high or the shearing force of the pouring system is large, and the plastic decomposes;
(5) The water content in the plastic is high, with impurities, black bars and silver wire;
(6) Poor plasticization;
(7) Poor cooling of crystalline materials, unevenness or uneven wall thickness of plastic parts.