Since the introduction of injection moldable Long Fiber Reinforced Thermoplastic (LFRT) composites, continued improvements in both manufacturing technology and processing methods, mechanical performance has dramatically improved. Notably, the step increase in multi- axial impact has significantly differentiated these long glass fiber composites from short glass fiber materials and can place the impact performance commensurate with glass mat thermoplastics (GMTs).
This paper will focus on the improvements in mechanical performance of polypropylene, polyamide, and polyphthalamide long glass fiber systems. Specific processing parameters as well as improved screw and tool designs have contributed and will be reviewed.
These thermoplastic composites fit many processing modes in addition to injection molding. Processing these materials via injection compression, structural foam molding, gas assist molding, blow molding, and extrusion compression molding adds greatly to their versatility for producing value-added structural plastic components for the automotive market. How the processing improvements affect the design of future parts will also be reviewed.
