The dents of PE pipe fittings are usually due to insufficient force on the product, insufficient material filling, and unreasonable product design. The dents often appear in the thick-walled part that is similar to the thin wall. The air holes are caused by insufficient plastic in the mold cavity, the outer ring plastic is cooled and solidified, and the internal plastic shrinks to form a vacuum. Most of it is caused by the hygroscopic materials not being dried well, and the residual monomers and other compounds in the materials.
To judge the cause of the pores, it is only necessary to observe whether the bubbles of the PE pipe fittings appear instantaneously when the mold is opened or after cooling. If it occurs instantaneously when the mold is opened, it is mostly a material problem, if it occurs after cooling, it is a problem with the mold or injection molding conditions.

(1) Material problem:

①Dry material ②Add lubricant ③Reduce volatile matter in the material

(2) Injection molding conditions

①Insufficient injection volume; ②Increase the injection pressure; ③Increase the injection time; ④Increase the total pressure time; ⑤Increase the injection speed; ⑥Increase the injection cycle; ⑦The injection cycle is abnormal due to operation reasons.

(3) Temperature problem

①Too hot material causes excessive shrinkage; ②Too cold material causes insufficient filling and compaction; ③Too high mold temperature causes the material at the mold wall to not solidify quickly; ④Too low mold temperature causes insufficient mold filling; ⑤The mold has local hot spots ⑥Change the cooling plan.

(4) Mold problem;

①Increase the gate; ②Increase the runner; ③Increase the main channel; ④Increase the nozzle hole; ⑤Improve the mold exhaust; ⑥Balance the mold filling rate; ⑦Avoid interruption of the mold filling flow; ⑧Gate feed arrangement In the thick-walled part of the product; ⑨If possible, reduce the difference in the wall thickness of the PE pipe fittings; ⑩The injection cycle caused by the mold is abnormal.

(5) Equipment problems:

①Increase the plasticizing capacity of the injection press; ②Make the injection cycle normal;

(6) Cooling condition problem:

①The PE pipe fittings are cooled too long in the mold to avoid shrinking from the outside to the inside and shorten the cooling time of the mold; ②The PE pipe fittings are cooled in hot water.