What is floating fiber?
What is floating fiber in injection molding?
Floating fiber is also called exposed fiber. In the production of elongated glass fiber / long carbon fiber raw material is most likely to appear is the surface appearance of the bad, mainly for burnt, exposed fiber and material flower. And this is the most important, the most difficult to solve is the exposed fiber. The so-called exposed fiber is the glass fiber exposed on the surface of the product, relatively rough, the appearance is more difficult to accept. White glass fiber in the plastic melt mold flow process exposed to the exterior, to be condensed after molding in the plastic surface to form a radial white traces, when the plastic parts for the black will be due to the increase in the color difference and more obvious.
Causes of floating fiber in LFT material
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1.In the plastic melt flow process, due to the glass fiber and resin mobility differences, and the mass density is different, so that the two have a tendency to separate, the density of small glass fiber floating to the surface, the density of the resin sinks into the inner, so the formation of the glass fiber exposed phenomenon;
2.Glass fiber and nylon compatibility is poor, due to the plastic melt in the flow process by the screw, nozzle, runner and gate friction shear effect, will cause local viscosity differences, at the same time it will destroy the glass fiber surface interface layer, the smaller the viscosity of the melt, the more serious the interface layer is damaged, the more serious the bond between the glass fiber and the resin is also the more small, when the bonding force is small to a certain extent, the glass fiber will get rid of the resin matrix When the bonding force is small to a certain extent, the glass fiber will get rid of the resin matrix and gradually accumulate to the surface and be exposed.
3.Due to the plastic melt in the flow process by the screw, nozzle, runner and gate friction shear force, will cause local viscosity differences, and at the same time will damage the glass fiber surface interface layer, the smaller the melt viscosity, the more serious the damage to the interface layer, the more serious the bond between the glass fiber and the resin is also smaller, when the bond is small to a certain extent, the glass fiber will get rid of the bonding of the resin matrix, and gradually to the surface of the cumulative and exposed.
4. plastic melt injection cavity, will form a "fountain" effect, that is, the glass fiber will flow from the inside to the outside, in contact with the surface of the cavity, due to the lower temperature of the mold surface, the quality of the light condensation of glass fibers was instantly frozen, if not in time to be fully surrounded by the melt will be exposed and the formation of the "floating fiber! ".
Therefore, the formation of "floating fiber" phenomenon, not only with the composition and properties of plastic materials, but also with the molding process.
