When the barrel temperature is too high, the high-temperature melt will easily decompose in the barrel and cause the plastic part to change color. If the entire plastic part discolors or has uneven color, it is often related to the molding process conditions. If the color near the feed port or the welded part is uneven, it is generally caused by the uneven distribution of the colorant or the nature of the colorant does not meet the requirements for use. Uneven color is often due to different phenomena reflected, and its causes are also different. Improve the distribution of fibers in the resin by adjusting the process parameters, and minimize the amount of lubricant and release agent Ĭhange to resin with better crystallization performance or improve the crystallization performance of melt by controlling the cooling conditions of plastic parts įor the raw materials prone to forming internal stress, the process conditions that can reduce the internal stress of the molding should be adopted. Remove foreign matter in the raw materials, purify the raw materials, and pre-dry the raw materials to reduce the moisture in the raw materials In addition, raw materials such as high-impact polystyrene and ABS have greater internal stress after molding, which will also cause stress discoloration. If the content of volatile matter in the raw material is too high, mixed with foreign materials or poorly dried after the fiber-reinforced raw material is formed, the fiber filler is unevenly distributed, accumulated and exposed, or the resin is lost after the surface of the plastic part is in contact with the solvent, and the fiber is exposed the crystallinity of the resin Too bad will affect the transparency of the plastic parts, and will cause the uneven color on the surface of the plastic parts. Raw materials do not meet the requirements for use If the injection molding equipment and mold are contaminated by colorants, thoroughly clean the hopper, barrel and mold cavity. The colorants should preferably be wet mixed. Especially for the more important indicators such as heat resistance temperature and dispersion characteristics, the process requirements must be met. Therefore, when selecting colorants, they should be carefully selected according to the process conditions and the color requirements of the plastic parts. In addition, the colorant is easy to float in the air, deposit in the hopper and other parts, contaminate the injection molding machine and mold, and cause uneven color on the surface of the plastic part. If the colorant or additive has poor thermal stability, it will be easily decomposed by heat in the barrel, causing the plastic part to change color. After entering the barrel, the dispersion is not good, resulting in uneven color. Some colorants are dry mixed with the raw materials and adhere to the surface of the pellets after being stirred. After being mixed into the melt, they will form a directional arrangement, resulting in uneven color on the surface of the plastic part. Some colorants are in the form of aluminum foil and flakes. If the dispersibility, thermal stability and particle morphology of the colorant cannot meet the process requirements, it will be impossible to produce a good luster product. The performance of the colorant is directly related to the color quality of the molded part. PPR Pipe Fitting Making Injection Molding MachineĬause analysis and solution of the uneven color of injection molded parts.Plastic Chair Making Injection Molding Machine.Auto-car Part Injection Molding Machine.FB Fruit Basket Injection Molding Machine.PVC Pipe Making Injection Molding Machine.Variable Energy Saving Injection Moulding Machine.Servo Energy Saving Injection Moulding Machine.
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