Analysis of the defects of scorched dark lines and

2022-07-27
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Analysis on the defects of scorched dark lines and poor gloss in plastic injection molding on the one hand, the machine barrel was not cleaned or there was a material pad at the nozzle after injection of thermosensitive plastic, which led to poor exhaust at the beginning of injection

II. Mold

(1) poor exhaust

(2) small gate or improper gate position

(3) the local resistance of the cavity is large, which makes the material flow converge slowly and makes it difficult to exhaust

three processes

(1) the barrel and nozzle temperature are too high

(2) the injection pressure or prepreg back pressure is too high

(3) the injection speed is too fast or the injection cycle is too long

four aspects of raw materials

(1) uneven particles and powder

(2) high content of volatile matter in raw materials

(3) too much lubricant and release agent

analysis of defects with poor gloss

on the one hand, equipment

(1) insufficient material supply

(2) the barrel was not cleaned during refueling

II. Mold

(1) the gate is too small or the runner is too thin

(2) the roughness of the cavity surface is poor before the experiment

(3) poor exhaust or mold temperature, such as one of the plastic bags used in the supermarket is too low

(4) no cold charging well

the scraped specimen shall not be damaged

three process aspects

(1) the barrel heating is uneven, and the barrel temperature is too high or too low

(2) the nozzle is too small or the prepreg back pressure is too low

(3) the injection rate is too large or too small in this standard

(4) uneven plasticization

four aspects of raw materials

(1) raw materials are not dried

(2) contains volatile substances

(3) excessive dosage of auxiliary agent or release agent

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