Research On Resin Flow Front Of Vacuum Infusion Molding Process

The composite material has applied in many fields for its advantages such as high specific strength and specific stiffness with excellent designability. However, the manufacturing cost accounted for most of the cost of the composite material. Vacuum infusion molding process(VIMP) has become a very attractive technology because of its low-cost, environment-friendly and scalabiltiy to very large structures. In VIMP, the resin infiltration determines the performance and quality of the product. As the resin front profile reflects the progress and quality of the resin infiltration and to a certain extent it is able to describe and predict the impregnation process, the analysis on resin flow behavior especially on front profile and pressure-velocity relation has great significance in guiding production.Based on Darcy law, the permeability of the glassfiber was measured and a simulation model considering distribution medium was developed. The simulation model was effective by contrasting the resin flow front with and without distribution medium. Based on this model, the impregnation of fiberglass reinforced resin matrix composites was numerically simulated. The distribution medium, fiberglass layer thickness and viscosity on VIMP microscopic impregnation was analyzed both in simulation and experiment.The results show that the resin flow front approximates a straight line type, so the fluctuation is small, the infiltration process is more stable and better. Increasing fiberglass layer thickness(2-12layers) can reduce the flow velocity of the resin and the resin flow front profile approximates a straight line type, so the fluctuation is small, and the final product has few dry spots. Changing the viscosity of the resin has little inpact on the flow front profile, but properly increasing the viscosity can enhance the strength and stiffness of the product.Based on the resin flow front profile, the infiltration process can be optimized in the manufacturing of variable thickness and thin-walled parts. The filling time can be controlled by distribution medium, the strength and stiffness can be enhanced by changing viscosity and good infiltration can be obtained by changing the number or positioning of filling ports to make sure the resin front profile approximates a straight line type.