Meaning
Composite engineering plastics incorporate short or long fibers to enhance the mechanical strength and thermal stability of the molded component. Industrial applications utilize glass reinforced polyamide to replace metal housings and brackets because it offers high tensile strength and weight savings. This material requires specialized screw designs and process parameters to avoid fiber breakage during compounding.
Fiber Length
Moulders monitor the length of the fibers because longer fibers provide superior impact resistance and load-carrying capacity. High shear during the injection phase can fracture the glass filaments, which reduces the structural performance of the molded part. Choosing low-shear screw configurations helps preserve the fiber integrity.
Anisotropic Behavior
The orientation of the fibers during cavity filling determines the directional strength and shrinkage of the molded part. Fiber alignment occurs along the flow lines, meaning the part is much stronger in the flow direction than across it. This anisotropy can cause warpage if the cooling rate is not uniform.
Correct gate positioning distributes the fibers to minimize internal stresses.
Tool Wear
Abrasive fibers cause rapid wear on the steel surfaces of the mould gates and screw flights. Hardened tool steels or specialized coatings are needed to extend the life of the tooling. These protective measures prevent dimensional drift over long production runs.
