Cause analysis of flash and overflow of injection

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Cause analysis of flash and overflow of injection molding products

how to overcome product flash and overflow:

Product overflow is often caused by mold defects. Other reasons include: injection force is greater than mold locking force, material temperature is too high, insufficient exhaust, excessive feeding, foreign matters on the mold, etc

⑴ mold problem:

① the cavity and core are not closed tightly; ② Cavity and core offset; ③ The formwork is not parallel; ④ Formwork deformation; ⑤ Foreign matters fall into the mold plane; ⑥ Insufficient exhaust; ⑦ The exhaust hole is too large; ⑧ Abnormal injection cycle caused by mold

⑵ equipment problem:

① the projection area of the product exceeds the maximum injection area of the injection press; ② Incorrect installation and adjustment of injection press formwork; ③ Incorrect mold installation; ④ The clamping force cannot be kept constant; ⑤ The formwork of the injection press is not parallel; ⑥ Uneven deformation of tie rod; ⑦ Abnormal injection cycle caused by equipment

⑶ injection condition problems:

① too low clamping force ② too high injection pressure; ③ The injection time is too long; ④ Full pressure injection time is too long; ⑤ The injection rate is too fast; The change-over switch should be turned to the "loading" position ⑥ the mold filling rate is different; ⑦ The material flow in the mold cavity is interrupted; ⑧ The feeding amount is controlled too much; ⑨ The operating conditions lead to abnormal injection cycle with investment range

⑷ temperature problem:

① the barrel temperature is too high; ② Nozzle temperature is too high; ③ Mold temperature is too high

(5) equipment problems:

① increase the plasticizing capacity of the injection press; ② 3. Make the indication accuracy: ± 1% and the injection cycle normal

(6) cooling conditions:

① the cooling of parts in the mold is too long to avoid shrinkage from outside to inside and shorten the cooling time of the mold; ② Cool the part in hot water

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