会社のニュース The Cause of Glass Fiber Reinforced PC Floating Fiber

 The production of glass fiber reinforced Polycarbonate (PC) components presents several challenges, including high melt viscosity leading to filling difficulties and potential warpage. However, one of the most persistent issues affecting surface quality is the "floating fiber" phenomenon. This defect is a major concern for manufacturers, especially for parts where aesthetics are critical.

  The "floating fiber" effect occurs during the injection molding process. As the molten PC/GF composite flows from the nozzle through the mold's runners and gates into the cavity, the different densities and flow characteristics of the PC polymer and the glass fibers create a tendency for separation. When the separation forces exceed the interfacial adhesion between the fiber and the polymer matrix, the components begin to segregate. The denser material moves inward, while the less dense glass fibers float toward the surface of the melt stream. Upon curing, these fibers become exposed, creating a speckled, white appearance on the product surface. Furthermore, the intense shear forces experienced by the melt as it passes through the screw, nozzle, and gates can cause localized variations in viscosity and damage the delicate interfacial layer that bonds the glass fiber to the PC resin. A lower melt viscosity exacerbates this problem, further reducing the cohesive force holding the fibers within the matrix. Once this adhesion is sufficiently weakened, the glass fibers are freed from the resin's restraint, accumulating and protruding on the surface of the molded part.