An Analysis of Factors Affecting Pull Force for the Pultrusion of Graphite/Epoxy Composites

The influence of process parameter settings on the pull force required for the pultrusion of two epoxy resin systems reinforced with unidirectional graphite fiber was investigated. Experiments were conducted using the Shell EPON 9310/9360/537 epoxy resin system and the Shell EPON 9420/9470/537 epoxy resin system. Five independent factors—fiber volume, line speed, die zone I temperature, die zone 2 temperature, and die zone 3 temperature—were examined in each study. Regression analysis was used to iden tify the factors and factor interactions that influence the pull force required for the pultru sion of each resin system and to develop mathematical models to describe the pull force. The models indicated that process variable interactions were especially significant. Re sponse surface methods were used to illustrate the nature of the interactions. Additional statistical techniques were employed to investigate the influence of resin viscosity on the pull force and the influence of pull force on the four-point flexural strength of the com posites produced.