Medicinal aluminum foil is usually produced by double-joint rolling, the dark surface of medicinal foil "bright spot" defects have been the aluminum processing process to solve the quality problems. The reason is that medicinal foil customers often use the dark side of medicinal foil as a surface for color printing, in order to ensure the quality of printing and appearance of the effect, the dark "bright spot" defects are not allowed to exist serious defects.
The cause of the "bright spot" defect in the dark side and the elimination measures:
(1) The Dark Side "bright spot" is due to aluminum foil double rolling, double-close lubrication conditions are abnormal, resulting in local oil film rupture, so that the point area and the substrate has a poor gloss caused;
(2) The surface roughness of the roll is uneven, there are damage or rolling materials have scratches, sticky and other defects, rolling process is easy to produce "bright spot" defects;
(3) The correctness of the physical and chemical indexes of rolling oil and additives is the key factor to eliminate the defects of "bright spot", especially in the double-hop rolling road and secondary double-joint rolling road;
(4) Low flash point, low viscosity double oil is conducive to the elimination of "bright spot" defects; (5) The size of the surface roughness of the roll and the amount of the volume under the secondary pressure have no effect on the "bright spot" defect, but have a great influence on the rolling speed.