In this study, the researchers focused on optimizing the molding process of composite materials using the Long Fiber Injection (LFI) method. They conducted a series of experiments to analyze the characteristics of polyurethane and different types of fibers. The findings of their research shed light on important aspects of the process. To evaluate adhesive strength, the researchers measured contact angles of glass fiber, carbon fiber, and polyurethane resin. They discovered that company B exhibited the highest adhesion, followed by companies K and D. Among the carbon fiber models, H2550 and T-700 displayed similar adhesive strength, while glass fiber model P209 demonstrated superior adhesion compared to R66A. The curing behavior of polyurethane resins was also investigated. Although company K''s resin showed the highest adhesive strength, its long curing time of 26 minutes and 40 seconds rendered it unsuitable for the LFI process, which required faster production cycles. On the other hand, company B''s resin exhibited a remarkably short curing time of just 5 minutes and 30 seconds, making it ideal for high-speed LFI production. Moreover, the researchers observed that increasing the catalyst content further reduced the curing time. The mechanical properties of polyurethane resins were analyzed by evaluating tensile strength and interfacial shear strength. Company B''s resin displayed the highest tensile strength, while both carbon fiber models exhibited comparable interfacial shear strength. Among the glass fiber models, P209 outperformed R66A in terms of shear strength. Based on these results, company B''s resin was selected as the preferred basematerial for LFI, along with carbon fiber model H2550 and glass fiber model P209. Determining the optimal fiber content was another important aspect of the study. By producing flat plates with varying fiber contents, the researchers found that a 20% carbon fiber content and a 30% glass fiber content yielded the best results. Beyond these thresholds, strength values declined, indicating the importance of maintaining an appropriate fiber content for optimal performance. Lastly, the researchers employed LFI equipment to produce polyurethane composite materials with different glass fiber contents. Tensile strength measurements revealed that the highest strength was achieved with a 25% glass fiber content, with a sharp drop observed beyond 35%. This decrease was attributed to reduced wettability between the matrix and fibers, as well as decreased resin fluidity with an increased number of fibers.