1) Short shot
Phenomenon: Plastic material does not
completely fill the cavity (Cavity)
Reasons and treatment methods: 1, the
metering setting is insufficient; 2, the injection pressure is too low; 3, the
mold temperature or the tube temperature is not insufficient; 4, the back
pressure is too low or no back pressure causes the screw to idling; 6, release too
much spray; 7 flow distance is too short or plastic flow is poor; 8, sprue or runner
is too small.2) Flash
Phenomenon: Plastic material overflows the cavity
Reason and treatment:
1, too many metering settings; 2, the injection pressure is too large; 3, the clamping force is insufficient; 4, the mold temperature is too high or the temperature of the tube is too high; 5, the plastic fluidity is too good; 6, the plastic crystallization rate is too Slow; 7,the parting line of the mold is not tight enough
3) Black spots
Phenomenon: black spots on the surface of the molded parts
Reason and treatment:
1. When the plastic is poured into the barrel, the paper bag scraps or sutures and dust are poured into the barrel; 2, the barrel, the screw, the material tube and the nozzle is not cleaned when refueling 4, Plastic factory out processing improperly, mixed with sundries; 5, the mold surface is not clean; 5, the color master selection error (cracking)
4) Brown Marks
Phenomenon: Black or yellow stripes appear on the surface of the molded article.
Reason and treatment:
1, the mold or plastic temperature is too high; 2, the plastic stays in the material tube for a long time; 3, the injection pressure is too high, shear heat; 4, the mold venting position is incorrect or too small; 5, the screw speed is too fast and the back pressure is too high; 6, the additive in the plastic is improper formulated, and the heat stability is poor;
5) Sink marks
Phenomenon: the surface of the finished product is sink, especially the sharp portion of the thickness (because the central cooling of the thick meat is slow)
Reason and treatment:
1, the injection pressure is too low, the holding time is too short; 2, the injection speed is too fast; 3, the mold and plastic temperature is too high; 4, the finished meat thickness is poorly designed; 5, the runner and the inlet gate is too small; 6, the parts of the mold are unevenly cooled; 7, the plastic shrinkage rate is too large, the crystallization speed is too slow
6) Bubble (Void)
There are two reasons of gaps in the finished product:
1 occurs in the thickness part of the product, which is formed by the central cooling contraction.
2, the decomposition of air, moisture or plastic volatilization.
Reason and treatment:
1, the injection pressure is too low, the holding time is too short; 2, the back pressure is too low; 3, the plastic temperature is too high, staying too long; 4, the finished meat thickness is poorly designed; 5, the mold flow path, the inlet gate too Small; 6, plastic drying is insufficient; 7, spraying agent too much.
The above is from baiduwenku
Grandshine has more than 10 years experience in mold design, mold development and plastic injection molding
www.grashine.com
Phenomenon: black spots on the surface of the molded parts
Reason and treatment:
1. When the plastic is poured into the barrel, the paper bag scraps or sutures and dust are poured into the barrel; 2, the barrel, the screw, the material tube and the nozzle is not cleaned when refueling 4, Plastic factory out processing improperly, mixed with sundries; 5, the mold surface is not clean; 5, the color master selection error (cracking)
Phenomenon: Black or yellow stripes appear on the surface of the molded article.
Reason and treatment:
1, the mold or plastic temperature is too high; 2, the plastic stays in the material tube for a long time; 3, the injection pressure is too high, shear heat; 4, the mold venting position is incorrect or too small; 5, the screw speed is too fast and the back pressure is too high; 6, the additive in the plastic is improper formulated, and the heat stability is poor;
Phenomenon: the surface of the finished product is sink, especially the sharp portion of the thickness (because the central cooling of the thick meat is slow)
Reason and treatment:
1, the injection pressure is too low, the holding time is too short; 2, the injection speed is too fast; 3, the mold and plastic temperature is too high; 4, the finished meat thickness is poorly designed; 5, the runner and the inlet gate is too small; 6, the parts of the mold are unevenly cooled; 7, the plastic shrinkage rate is too large, the crystallization speed is too slow
6) Bubble (Void)
There are two reasons of gaps in the finished product:
1 occurs in the thickness part of the product, which is formed by the central cooling contraction.
2, the decomposition of air, moisture or plastic volatilization.
Reason and treatment:
1, the injection pressure is too low, the holding time is too short; 2, the back pressure is too low; 3, the plastic temperature is too high, staying too long; 4, the finished meat thickness is poorly designed; 5, the mold flow path, the inlet gate too Small; 6, plastic drying is insufficient; 7, spraying agent too much.
The above is from baiduwenku
Grandshine has more than 10 years experience in mold design, mold development and plastic injection molding
www.grashine.com
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