The production of plastic toys requires the consumption of petroleum resources, while petroleum resources are non-renewable resources. It is everyone’s responsibility to produce high-quality plastic products with limited resources. Sometimes, the surface of plastic injection molding will appear dull, or shiny, uneven color. Why? For this phenomenon, summarize the reasons and solutions.
1. The injection speed of the injection molding machine is too fast, and the material retention time is too long, which may cause the surface gloss of the injection molded product to decrease. Solution: Reduce the injection speed of the injection molding machine and reduce the residence time of the material.
2, the material thermal stability is poor, generally in the 100 ° C environmental conditions are prone to decomposition, 180 ° C decomposition will accelerate. Solution: Use materials with good thermal stability and good gloss, or add a reasonable amount of heat stabilizer to the material.
3. During the processing, the mold temperature is too low, and the cooling rate is too fast. When the melt is still filling the mold, a hard shell has formed on the cavity wall, and the hard shell is easily subjected to various forces to make it change. It becomes white and reduces the surface gloss of the product. Solution: Before starting to use the mold, heat the mold in advance, increase the working temperature of the mold, reduce the cooling rate or use local heating at the mold gate.
4. The moisture absorption or volatile content of raw materials is a common cause of poor gloss on the surface of plastic products. Solution: Dry the material thoroughly before use and add a dryer if necessary.
5. Excessive use of release agents can also cause such defects on the surface of plastic products. Solution: Try not to use or use a small amount of release agent, and apply evenly.
6. The quality of the raw materials of the product has a great influence on the surface gloss of the plastic products. Only the mixed impurities will reduce the gloss of the surface of the product. Solution: Use high quality raw materials or remove impurities before use.
7. The flow path and gate size of the injection molding machine are too small, and the poor exhaust gas will also cause the surface gloss of the product to be poor. Solution: The runner and gate size should be increased and the exhaust vent should be added.