The occurrence of such defects is mainly caused by the problems of plastic parts colored with masterbatch, although the color masterbatch is superior to dry powder coloring and dyeing in terms of color stability, color purity and color migration. Coloring, but the distribution, that is, the color particles in the diluted plastic in the degree of uniformity is relatively poor, the finished product naturally has a regional color difference.
(1) Increasing the temperature of the feeding section, especially the temperature at the rear end of the feeding section, so that the temperature is close to or slightly higher than the temperature of the melting section, so that the masterbatch is melted as soon as it enters the melting section, promoting uniform mixing with the dilution, and increasing the chance of liquid mixing.
(2) When the screw rotation speed is constant, the back pressure is increased to increase the temperature and shearing action of the melt in the cylinder.
(3) Modify the mold, especially the pouring system. If the gate is too wide, the turbulence effect is poor when the melt passes, and the temperature rise is not high, so it is not uniform, and the ribbon cavity should be narrowed.