Scorch

◆ possible causes related to process and equipment

1. The rate of fire (pressure) is too high
2. The melt temperature is too high
3. The back pressure is too high
4. The diameter of the nozzle is too small
5. Nozzle temperature is too high
6. High material pipe temperature
7. The screw speed is too fast

◆ possible causes related to the mold

1. Improper gate type or position
2. Gate diameter is too small
3. Poor mold exhaust

◆ possible causes related to materials

1. The material is not heat-resistant enough
2. Too many secondary materials
3. The high-temperature stability of the material is not enough

Low Gloss

◆ possible causes related to process and equipment

1. The barrel temperature is too low
2. Insufficient injection pressure
3. Low nozzle temperature
4. The melting time in the feeding tube is too long
5. Improper forming cycle

◆ possible causes related to the mold

1. Poor mold finish.
2. The gate or runner is too small
3. Improper gate type or position
4. Poor exhaust
5. There are foreign matters on the surface of the mold.

◆ possible causes related to materials

1. The material is not sufficiently dry
2. Improper flow performance
3. Poor gloss of the material

Flash

◆ possible causes related to process and equipment

1. The injection pressure (speed) is too high
2. The glue stays in the material pipe for too long
3. The molding cycle is too long
4. Insufficient clamping force
5. The material temperature is too high

◆ possible causes related to the mold

1. Poor contact of clamping surface
2. Insufficient mold strength
3. Poor exhaust
4. The sprue is too long
5. The size of mold accessories is not precise

◆ possible causes related to materials

1. Liquidity is too good
2. Too much lubricant

Sunken

◆ possible causes related to process and equipment

1. The barrel or mold temperature is too high
2. The injection pressure, speed, and back pressure are too low, and the injection time is too short
3. Insufficient holding pressure (time)
4. Poor cooling time setting
5. The check valve is poor

◆ possible causes related to the mold

1. The gate or runner is too small
2. Gate position or type selection is poor
3. The gate solidifies too early
4. The reinforcement is too thick
5. Flow imbalance

◆ possible causes related to materials

1. The fluidity and shrinkage of materials are unqualified
2. Excessive amount of returned materials

Flow mark

◆ possible causes related to process and equipment

1. The barrel temperature is too low
2. The injection pressure is too low
3. Insufficient holding pressure (time)
4. Improper cycle time
5. The glue stays in the feeding tube too long

◆ possible causes related to the mold

1. Mold temperature is too low
2. The gate or runner is too small
3. Poor exhaust

◆ possible causes related to materials

1. Material fluidity does not meet the requirements
2. Improper lubricant
3. Too many volatile substances

Crackle

◆ possible causes related to process and equipment

1. Excessive filling, pressure maintaining, and excessive residual stress
2. The pressure of maintaining time is too long
3. Mold temperature is too low

◆ possible causes related to the mold

1. Insufficient demoulding slope
2. Poor ejection
3. Too much release agent

◆ possible causes related to materials

1. Poor drying
2. Too much secondary material
3. High-temperature decomposition of materials

Black dot

◆ causes of bad black spots

1. The injection molding machine is not cleaned thoroughly
2. The temperature of the injection molding machine is set too high
3. The structure of the injection nozzle of the injection molding machine is unreasonable
4. The retention time is too long, which is easy to scorch and produce black spots
5. The drying bucket is not cleaned thoroughly
6. The air blowing (suction) device of the drying bucket is polluted by the filter screen
7. The storage barrel is not cleaned thoroughly
8. Improper management of handling, unpacking, and feeding process, which is easy to bring dust and other impurities into the surrounding environment
9. The black spots of the product itself should be fed back in time for the convenience of investigation