Performance of glass fiber reinforced injection molding
1.Good adhesion between the fiber and the substrate is critical to the mechanical properties of the component. Compared with direct processing molding compound and long glass fiber pellet, GMT can provide higher strength and impact strength. Because the fibers and filaments can be well bonded, and the filaments are evenly distributed, the needled felt structure is formed, which has many advantages. However, if the flow path is too long in the compression molding process, the above advantages no longer exist. Since the fiber orientation can be formed in the parts by injection molding, the defect of lacking needle punching performance can be partly offset if the stress is reasonably designed.
2.In this paper, the processing method is concluded based on the damage of fiber structure in composite materials. Fiber structure damage includes fiber fracture, fiber debonding and fiber pullout. When making full use of fiber strength, it is necessary to ensure that the fiber length is longer than the so-called critical fiber length. For fiber / matrix composites composed of PP and glass, the corresponding literature values of critical fiber length (LC) are 1.3 mm ~ 3.1 mm. With a special coupling agent, values up to 0.9 mm can be produced.
3.The coupling mass of the fiber substrate can be inferred from the ratio between the actual fiber length and the critical fiber length. If the actual fiber length of the component is greater than the critical fiber length, the fiber is prone to fracture. If it is less than the critical fiber length, fiber pullout may occur. This mainly refers to the fracture of the fiber / substrate interface, which usually occurs in the cut-off fiber mixture with a fiber length of 0.2 mm ~ 0.6 mm.