3. Molding materials do not meet the requirements for use
(1) The content of moisture or other volatile substances in the molding raw material is too high, and the volatile components are condensed in the cavity wall of the mold and the melt during molding, resulting in poor gloss on the surface of the plastic part. The raw materials should be pre-dried.
(2) Discoloration of raw materials or colorants leads to poor gloss. Raw materials and colorants with high temperature resistance should be used.
(3) The flowability of the raw material is too poor, so that the surface of the plastic part is not dense and the gloss is poor. Replace the resin with better flow properties or add appropriate amount of lubricant and increase the processing temperature.
(4) Raw materials are mixed with foreign materials or incompatible materials. Should be replaced with new materials.
(5) The raw material particle size is not uniform. Raw materials with too different particle sizes should be screened out.
(6) The crystalline resin is poor in gloss due to uneven cooling. The mold temperature and processing temperature should be reasonably controlled. For thick-walled plastic parts, if the cooling is insufficient, the surface of the plastic part will be hairy and the gloss will be dark. The solution is to remove the plastic parts from the mold and immediately put them into the cold water. The cooling die is cooled and shaped.
(7) The proportion of recycled materials in the raw materials is too high, which affects the uniform plasticization of the melt. The amount should be reduced.