Manufacturing Mechanism And Experimental Study On Continuous Carbon Fiber Reinforced Thermoplastic Towpreg Tape

Carbon fiber is a kind of material with excellent comprehensive performances. Prepreg is the intermediate product of carbon fiber industry chain. Prepreg tape, which is strip prepreg, is widely used in many carbon fiber composite parts, such as aircraft wing, auto body and wind turbine blades.Due to the excellent mechanical properties, recyclable, and other characteristics, continuous thermoplastic towpreg tape is a new development direction of the carbon fiber prepreg tape. However, its production has many problems. Tow width and evenness is relatively discrete, and the impregnated resin distribution is not uniform. Therefore, it is very important to study tow spreading and powder impregnation, which are two key technologies of continuous carbon fiber thermoplastic towpreg tape. The mainly research works of this paper are summarized as follows:(1) Process design and equipment optimization of continuous carbon fiber thermoplastic towpreg tape. Fluidized powder impregnation technique was used to manufacture continuous carbon fiber thermoplastic towpreg tape. Its manufacturing processes can be divided into five processes: unwinding, pneumatic spreading, powder coating, resin infiltration and winding. Among them, the core processes are pneumatic spreading, powder coating and resin infiltration.(2) Numerical analysis and experiments of carbon fiber tow pneumatic spreading process. Based on force analysis, a mathematic model was presented to predict the spreading width and eveness of carbon fiber tow. A self-designed tow pneumatic spreading experimental platform was built, and several experiments were carried out on this platform. The experimental results are well consistent with the theoretical predicted values based on the model. In the pneumatic spreading process, the optimal combination of parameters values is: air velocity(7.5 m/s), fiber transport velocity(1.5 m/min), tow tension(120 gf).(3) Numerical analysis and experiments of powder impregnation. The powder impregnation process can be divided into two steps: powder coating and resin infiltration. In this paper, the mechanism of the powder coating was analyzed, orthogonal experiments and single factor experiments were carried out, and the influence of various parameters on the resin content was studied. This paper also established a theoretical model of the time that resin completely infiltrated carbon fiber tow. Several experiments of resin infiltration were carried out. The change trend of the experimental results and the theoretical model are consistent.(4) Performance analysis of continuous carbon fiber thermoplastic towpreg tape. This paper developed a test production line of continuous carbon fiber thermoplastic towpreg tape using fluidized powder impregnation technique. 100 meters of towpreg tape was produced by the test production line. The deviation of spreading width is within 1mm, and the deviation of resin content is less than 1%.