Glass fiber reinforced material injection molding

Author: MULAN – Plastic Molding Manufacturer

The editor is often asked by customers, "Can your family do injection molding of glass fiber reinforced materials?" Today, the editor answers very responsibly: Mulan Shenzhen Injection Mold Factory can do injection molding of glass fiber reinforced materials, for example: PA+30% GF, PA+60%GF. So what are the headaches in the injection molding of glass reinforced materials? The most important possibility is that there will always be floating fibers in the injection molding products of glass fiber reinforced materials. How to solve it? Take nylon plus glass fiber as an example. 1) The compatibility between glass fiber and nylon is poor. During the modification process, nylon has low fluidity and does not fully infiltrate glass fiber.

2) During the injection molding process, since the plastic melt is subjected to friction and shear forces at the screw, nozzle, runner and gate during the flow process, it will cause local viscosity differences, and at the same time, it will damage the contact surface of the glass fiber surface , the smaller the viscosity of the contact surface, the more serious the damage of the contact surface, and the smaller the bonding force between the glass fiber and the resin. When the bonding force of the contact surface is small enough, the glass fiber will break away from the shackles of the resin matrix and gradually The surface is accumulated and exposed. 3) It is related to the difference in specific gravity between the glass fiber and the base material. During the melting process, due to the different fluidity and mass density between the glass fiber and the resin, the two tend to separate, the glass fiber floats to the surface, and the resin Sinks to the inside, thus forming glass fiber exposure. 4) Fountain effect. When nylon melt is injected into the mold, a "fountain effect" will occur, that is, the glass fiber will flow from the inside to the outside and contact the surface of the cavity. Due to the low temperature of the injection mold surface, the glass fiber will be instantly lightened. Condensation Congeals rapidly, and if it cannot be completely wrapped by the melt in time, it will be exposed to form "floating fibers".

Therefore, the "floating fiber" phenomenon in the injection molding of glass fiber reinforced materials not only involves the composition and properties of plastic materials, but also involves the injection molding process, which has great complexity and uncertainty.