Summary of faults and Countermeasures for injection molding of polyolefin plastics

Underinjection

(1) Melt temperature is too low. The temperature of barrel and nozzle shall be properly increased.

(2) The molding cycle is too short. It shall be extended appropriately.

(3) The injection pressure is low. It should be properly improved.

(4) The injection speed is too slow. It should be accelerated appropriately.

(5) The pressure holding time is too short. It shall be extended appropriately.

(6) Insufficient supply. The feeding volume shall be increased.

(7) Screw back pressure is low. It should be properly improved.

(8) The structural size of gating system is too small. Gate and runner sections shall be suitably enlarged.

(9) Poor mold exhaust. Mold exhaust shall be increased.

• Insufficient die strength. The die rigidity shall be improved as much as possible.

molding flash

(1) The melt temperature is too high. The temperature of barrel and nozzle shall be properly reduced.

(2) The injection pressure is too high. It shall be reduced appropriately.

(3) The injection speed is too fast. Slow down properly.

(4) The pressure holding time is too long. It shall be shortened appropriately.

(5) Excessive feed. The feeding amount shall be appropriately reduced.

(6) Insufficient clamping force. The clamping force shall be increased.

(7) Insufficient die strength. The die rigidity shall be improved as much as possible.

(8) The setting of inserts is unreasonable. It shall be adjusted appropriately.

(9) The gate section is large. It shall be reduced appropriately.

(10) The mold is poorly installed and the benchmark is not aligned. The mold should be reassembled.

Bubble

(1) The melt temperature is too high. The temperature of barrel and nozzle shall be properly reduced.

(2) The molding cycle is too long. It shall be shortened appropriately.

(3) The injection pressure is low. It should be properly improved.

(4) The injection speed is too fast. Slow down properly.

(5) Pressure holding time is too short. It shall be extended appropriately.

(6) The mold temperature is uneven. The mold cooling system and flow shall be set reasonably.

(7) Poor mold exhaust. Mold exhaust shall be increased.

(8) The product structure design is unreasonable and the wall is too thick. Adjustments should be made where possible.

(9) Gate section is too small. It shall be properly enlarged.

Warpage deformation

(1) Melt temperature is too low. The barrel temperature shall be properly increased.

(2) The molding cycle is short. It shall be extended appropriately.

(3) The injection pressure is too high. It shall be reduced appropriately.

(4) The injection speed is too fast. Slow down properly.

(5) The pressure holding time is too long. It shall be shortened appropriately.

(6) The mold temperature is uneven. The mold cooling system and flow shall be set reasonably.

(7) Gate section size is too small. It shall be properly enlarged.

(8) The setting of ejector is unreasonable. The ejection cross-sectional area and ejection point shall be increased as much as possible.

(9) Insufficient die strength. The die rigidity shall be improved as much as possible.

Shrinkage depression

(1) The melt temperature is too high. The barrel temperature shall be properly reduced.

(2) The injection pressure is too low. It should be properly improved.

(3) Mold temperature is too high. It shall be reduced appropriately.

(4) The product wall is too thick. Adjustments should be made where possible.

(5) Gate section size is too small. It shall be properly enlarged.

(6) The molding cycle is too short. It shall be extended appropriately.

(7) Pressure holding time is too short. It shall be extended appropriately.

Weld mark

(1) Melt temperature is too low. The temperature of barrel and nozzle shall be properly increased.

(2) The injection pressure is too low. It should be properly improved.

(3) The injection speed is too slow. It should be accelerated appropriately.

(4) Mold temperature is too low. It should be properly improved.

(5) The product structure design is unreasonable or the wall is too thin. Adjustments should be made where possible.

(6) The structural size of gating system is too small. Gate and runner sections shall be suitably enlarged.

(7) The cold cavity in the die is too small. It shall be properly enlarged.

(8) Foreign matters and impurities are mixed in the raw material. It shall be removed.

(9) The amount of release agent is too much. Its dosage should be minimized.

(10) Uneven coloring of raw materials. The coloring of raw materials shall be uniform.

Scorched black lines

(1) The melt temperature is too high, resulting in overheating decomposition. The barrel temperature shall be properly reduced.

(2) The molding cycle is too long. It shall be shortened appropriately.

(3) The injection speed is too fast. Slow down properly.

(4) Screw back pressure is too high. It shall be reduced appropriately.

(5) Gate section size is too small. It shall be properly enlarged.

(6) Poor mold exhaust. Mold exhaust shall be increased.

(7) Poor drying of raw materials. The drying temperature should be increased and the drying time should be prolonged.

(8) Too much release agent. Its dosage should be minimized.

Surface scratch

(1) The injection pressure is too high. It shall be reduced appropriately.

(2) The pressure holding time is too long. It shall be shortened appropriately.

(3) Mold temperature is too low. It should be properly improved.

(4) The setting of ejector is unreasonable. The ejection cross-sectional area and ejection point shall be increased as much as possible.

(5) Insufficient demoulding slope. It shall be increased appropriately.

Low Gloss

(1) The melt temperature is low. The temperature of barrel and nozzle shall be properly increased.

(2) The molding cycle is too long. It shall be shortened appropriately.

(3) The mold temperature is low. It should be properly improved.

(4) The structural size of gating system is too small. Gate and runner sections shall be suitably enlarged.

(5) Poor mold exhaust. Mold exhaust shall be increased.

(6) Foreign matters and impurities are mixed in the raw material. Raw materials shall be removed or replaced.

(7) Too much release agent. Its dosage should be minimized.

Uneven color

(1) Barrel temperature too high. The barrel temperature shall be properly reduced.

(2) The molding cycle is too long. It shall be shortened appropriately.

(3) Screw back pressure is too low. It should be properly improved.

(4) Uneven coloring of raw materials. The coloring of raw materials shall be uniform.

Delamination stripping

(1) Melt temperature is too low. The temperature of barrel and nozzle shall be properly increased.

(2) Screw back pressure is too high. It shall be reduced appropriately.

(3) Foreign matters and impurities are mixed in the raw material. It shall be removed.