Causes of Defects in Injection Molding Parts and R

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1. Characteristic of Injection Molding Part Defects

The injection process is incomplete because the cavity is not filled with plastic or the injection process lacks some details.

2. Reasons for possible problems

(1) Insufficient injection speed.

(2) Plastic shortage.

(3) No screw pad was left at the end of the stroke.

(4) Running time changes.

(5) The temperature of the injection cylinder is too low.

(6) Insufficient injection pressure.

(7) The nozzle part is sealed.

(8) The heater outside the nozzle or the injection cylinder cannot operate.

(9) Injection time is too short.

(10). Plastic is attached to the throat wall of hopper.

(11) The capacity of the injection moulding machine is too small (i.e. injection weight or plasticizing capacity).

(12). Mould temperature is too low. (13). No rust-proof oil was cleaned.

(14). The stop ring is damaged and the melt has backflow phenomenon.

3. Remedies

(1) Increase the injection speed.

(2) Check the amount of plastic in the hopper.

(3) Check whether the injection schedule is set correctly and make changes if necessary.

(4) Check whether the check valve is worn or cracked.

(5) Check the stability of operation.

(6) Increase the melt temperature.

(7) Increase back pressure.

(8) Increase injection speed.

(9) Check whether there is any foreign body or plastics in the perforation hole.

(10). Check all heater outer layers with ammeters to verify that the energy output is correct.

(11). Increase screw forward time.

(12) Cooling capacity in throat zone of feeder or temperature in back zone of feeder cylinder.

(13) Use larger injection moulding machines.

(14). Appropriately raise the die temperature.

(15). Clean up the rust-proof agent in the mould.

(16). Check or replace the stop ring.