Hot/cold cycle blow mold injection molding technology c […]
Hot/cold cycle blow mold injection molding technology can greatly improve the appearance of injection molded parts. The most outstanding function is the use of amorphous resin processing parts, including resin varieties: PC resin, PC / ABS compound, PC / PBT compounding. When the external temperature of the blow mold is higher than the Tg of an amorphous resin, the resin melt does not form a layer of skin during the injection, and the melt can move freely. The result: when the melt hits the exterior of the blow mold, it does not freeze, which is different from the traditional injection molding skills.
During filling, a thin layer of polymer melt escapes, leaving the outer surface of the mat template, thereby increasing the gloss of the part and reducing the surface roughness. The research results show that if the gloss of the parts is improved by 50% to 90%, the surface roughness index -Rmax can be improved by 70% for the glass fiber reinforced materials, and the index related to the unfilled data should be improved by 20%.
Hot/cold blow mold injection molding skills have a positive impact on improving the width and visibility of weld lines. In the same blow molding mold, I walked into the processing comparison test of three different materials. The results showed that the products processed by the traditional injection molding skills have a weld line width of about 6 to 13 microns. The products obtained by injection molding on the cold blow mold were completely invisible to the weld line and could not be detected in width. This infinite advantage eliminates the need for secondary processing such as painting, and is particularly suitable for certain special occasions.
The residual internal stress of the injection molding in the product can cause the component to warp or even shorten the service life of the component. Conventional injection molded parts have high internal stresses. Carbon tetrachloride is attributed to a known solvent that causes stress cracking of plastic parts. The plastic parts processed by the hot/cold cycle blow molding die have low internal stress, and the use of such a solvent does not constitute stress cracking of the component, and then the annealing treatment process required before the component is used can be omitted.