The direct fiber feeding injection molding (DFFIM) process is the new fabrication technique. This technique is able to eliminate the compounding process. In this study, the composite consisting of glass fiber/carbon fiber/ABS (GF/CF/ABS) were fabricated. Tensile, bending and Izod impact test were conducted to compare mechanical properties between glass fiber and glass fiber/carbon fiber hybrid composites. The additional of carbon fiber improved tensile, bending and impact properties of the hybrid composites. SEM photographs indicated that carbon fiber tended to agglomerate during DFFIM process. It can be noted that the low content of carbon fiber was suitable for enhanced mechanical performances of GF/CF/ABS hybrid composites.

GF reinforced polymer composites to improve the mechanical properties by increasing fiber content, but there is a limit. On the contrary, CF reinforced polymer composites are superior to the GF composites at a lower CF content in tensile and bending properties. However, CF is more expensive than GF. In this study, acrylonitrile butadiene styrene (ABS) was reinforced with single and hybrid reinforcing of glass fibers (GF) and carbon fibers (CF). The composites consisting of GF/ABS, CF/ABS and GF/CF/ABS were fabricated by direct fiber feeding injection molding (DFFIM). The reinforcing fiber was directly fed at the vent hole of the barrel in the DFFIM process. The effects of fiber Tex, fiber numbers and processing parameters on properties of the composites were investigated. Tensile, bending and Izod impact testing was conducted to compare mechanical properties of GF/ABS composites, CF/ABS composites and hybrid GF/CF/ABS composites. Morphology of the composites was observed by scanning electron microscopy. In addition, the cost advantage of each composite was compared with their mechanical properties. From the results, the addition of carbon fiber improved tensile, bending and impact properties of the hybrid composites. SEM photographs indicated that carbon fiber tended to agglomerate during the DFFIM process. The hybrid GF/CF/ABS composites presented an equivalent improvement in tensile and bending properties as compared to the CF/ABS composites. It can be noted that the low CF content was suitable for enhanced mechanical performances of the hybrid GF/CF/ABS composites. Therefore, the hybrid composites can be manufactured at a low cost as compared to the similar mechanical properties of the CF/ABS composites.