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:
1. Dry material 2. Add lubricant 3. Reduce volatile matter in the material
(2) Injection molding conditions
1. Insufficient injection volume; 2. Increase the injection pressure; 3. Increase the injection time; 4. Increase the total pressure time; 5. Increase the injection speed; 6. Increase the injection cycle; 7. The injection cycle is abnormal due to operation reasons.
(3) Temperature problem
1. Too hot material causes excessive shrinkage; 2. Too cold material causes insufficient filling and compaction; 3. Too high mold temperature causes the material at the mold wall to not solidify quickly; 4. Too low mold temperature causes insufficient mold filling; 5. The mold has local hot spots 6. Change the cooling plan.
(4) Mold problem;
1. Increase the gate; 2. Increase the runner; 3. Increase the main channel; 4. Increase the nozzle hole; 5. Improve the mold exhaust; 6. Balance the mold filling rate; 7. Avoid interruption of the mold filling flow; 8. Gate feed arrangement In the thick-walled part of the product; 9. If possible, reduce the difference in the wall thickness of the PE pipe fittings; 10. The injection cycle caused by the mold is abnormal.
(5) Equipment problems:
1. Increase the plasticizing capacity of the injection press; 2. Make the injection cycle normal;
(6) Cooling condition problem:
1. The 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; 2. The PE pipe fittings are cooled in hot water.
Company Name: Ningbo Pntek Technology Co., Ltd.
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