Failure analysis and troubleshooting methods:
(1) Improper control of process conditions. Should be adjusted appropriately.
(2) Injection capacity of injection molding machine is less than weight of plastic part. A larger injection molding machine should be used.
(3) Cross section of runner and gate is too small. Should be increased appropriately.
(4) Flow distance of melt in cavity is too long or there are thin-walled parts. Cold slug should be set.
(5) Poor mold exhaust, and residual air in mold cavity causes insufficient injection. Exhaust system of mold should be improved.
(6) Fluidity of raw materials is too poor. Resin with better flow properties should be used instead.
(7) Temperature of barrel is too low, injection pressure is insufficient, or injection time of replenishment is too short, which will also cause short injection. Control amount of related process parameters should be increased accordingly.

 

Failure analysis and troubleshooting methods:
(1) Insufficient clamping force. A larger injection molding machine should be used.
(2) Pin holes or guide pins of mold are severely worn. It should be repaired by machining methods.
(3) There are foreign matter and impurities on clamping surface of mold. Should be cleared.
(4) Mold temperature or injection pressure is too high. Should be reduced appropriately.

Failure analysis and troubleshooting methods:
(1) Mold runner and gate size of thick-walled plastic parts are prone to surface pores when size is small. Size of runners and gates should be appropriately enlarged.
(2) Wall of plastic part is too thick. In design, wall thickness should be minimized.
(3) Too high molding temperature or too low injection pressure will cause pores on the surface of plastic part. Molding temperature should be appropriately lowered and injection pressure should be increased.

Failure analysis and troubleshooting methods:
(1) Melting material and mold temperature are too low. Barrel and mold temperature should be appropriately high.
(2) Injection speed is too slow. Injection speed should be increased appropriately.
(3) Nozzle aperture is too small. You should switch to a nozzle with a larger aperture.
(4) There is no cold material cavity in mold. Cold slug hole should be added.

 

Failure analysis and troubleshooting methods:
(1) Content of moisture and volatile matter in molding material is too high. Raw materials should be pre-dried.
(2) Poor mold exhaust. Exhaust holes should be added to improve exhaust performance of mold.
(3) Poor contact between nozzle and mold. Positions and geometric dimensions of two should be adjusted.
(4) When silver bars always appear in a certain position, check whether there are surface scars on the surface of corresponding cavity. If there is a re-imaging phenomenon of surface scars, machining methods should be used to remove scars on the surface of mold cavity.
(5) When different types of resin are mixed, silver streaks will be produced. Mixing of dissimilar resins should be prevented.

Failure analysis and troubleshooting methods:
(1) Temperature of melt and mold is too low. Temperature of barrel and mold should be increased.
(2) Location of gate is unreasonably set. Gate position should be changed.
(3) Content of volatile matter in raw material is too high or mold exhaust is poor. Volatile substances in raw materials should be removed and exhaust system of mold should be improved.
(4) Injection speed is too slow. Should be accelerated appropriately.
(5) There is no cold material cavity in mold. Cold slug hole should be added.
(6) There are foreign matters on the surface of cavity. Should be cleaned.
(7) Design of gating system is unreasonable. Filling performance of gating system should be improved to make melt flow smoothly in cavity.

 

Failure analysis and troubleshooting methods:
(1) Specifications of injection molding machine are too large. It should be replaced with a smaller injection molding machine.
(2) Resin has poor flow properties. An appropriate amount of external lubricant should be used.
(3) Injection pressure is too high. Should be reduced appropriately.
(4) Poor mold exhaust. Exhaust system of mold should be improved, vent holes should be increased or an inlaid structure should be used, clamping force should be appropriately reduced.
(5) Unreasonable gate location setting. Gate position should be changed to make melt in cavity flow evenly.

Failure analysis and troubleshooting methods:
(1) Gate and runner size are too small. Should be increased appropriately.
(2) Injection pressure is too low. Should be increased appropriately.
(3) Moisture content in raw material is too high. Raw materials should be pre-dried.
(4) Wall thickness of plastic part changes too much. Shape and structure of plastic parts should be designed reasonably to avoid sudden changes in wall thickness.

 

Failure analysis and troubleshooting methods:
(1) Temperature of melt and mold is too low. Temperature of barrel and mold should be increased.
(2) Structural design of mold's gating system is unreasonable. Mold runner and gate structure should be improved so that melt does not produce turbulent flow during mold filling.
(3) Cooling time is too short. Cooling time should be extended appropriately.
(4) Design of ejector device for demoulding is unreasonable. It is best to use a pneumatic demoulding device.
(5) Injection speed and pressure are too high. Should be reduced appropriately.

Failure analysis and troubleshooting methods:
(1) Mold temperature is too high or cooling is insufficient. Mold temperature should be appropriately lowered or cooling time should be extended. For slender plastic parts, method of cooling after fixing mold can be adopted.
(2) Uneven cooling. Cooling system of mold should be improved to ensure uniform cooling of plastic parts.
(3) Gate type selection is unreasonable. A reasonable gate form should be selected according to specific situation. In general, multi-point gates can be used.
(4) Mold is eccentric. Should be checked and corrected.

Failure analysis and troubleshooting methods:
(1) Injection speed and pressure are too high. Should be reduced appropriately.
(2) Surface finish of mold cavity is too poor. Surface finish should be improved by grinding and electroplating.
(3) Improper control of mold temperature and cooling conditions. When plastic part sticks to mold core, mold temperature should be increased and cooling time should be shortened; if plastic part sticks to surface of cavity, mold temperature should be lowered and cooling time should be prolonged.
(4) Ejection area of demoulding mechanism is too small. Ejection area should be increased.

Failure analysis and troubleshooting methods:
(1) Insufficient holding pressure. Injection time of refill should be extended appropriately.
(2) Insufficient injection pressure. Should be increased appropriately.
(3) Mold temperature is too high. Should be reduced appropriately.
(4) Cross-sectional area of gate is too small. Should be increased appropriately.
(5) Processing temperature is too low. Temperature of barrel should be appropriately increased.

Failure analysis and troubleshooting methods:
(1) Insufficient holding pressure. Injection time of refill should be extended appropriately.
(2) Mold temperature is too low and barrel temperature is too high. Temperature of mold should be appropriately increased and temperature of barrel should be reduced.
(3) Insufficient injection pressure. Should be increased appropriately.
(4) Fluidity of raw material is too good. Resin with a lower melt index should be used instead.