Pretreatment of aircraft carbon fiber-reinforced plastic skin by plastic abrasive jet machining

Abstract

In this study, a new pretreatment method was proposed for efficient nondestructive substrate pretreatment of carbon fiber-reinforced plastic (CFRP) skin stealth coatings for 4th and 5th generation fighter jets, which can effectively replace hand sanding and meet the requirements of high efficiency and damage prevention of the substrate. Erosion experiments were carried out on a commercial sandblasting cabinet by the Taguchi method for CFRP skin pretreatment. The mechanisms of hand sanding and plastic abrasive jet machining (PAJM) were introduced in detail. The advantages of PAJM over hand sanding for CFRP skin pretreatment were investigated in terms of surface morphology, wettability, and adhesion, in order to achieve the objective of enhancing coating adhesion and prolonging the service life of the substrate. These results show that the damage of PAJM-eroded surfaces is lower than that of hand-sanded surfaces, and safe process parameters for no fiber damage are provided. The critical pressure of carbon fiber damage was likely to be 0.4 MPa or lower, and the adhesion of primer could reach 3.6 MPa. This study provides significant guidance for the pretreatment of new-generation aircraft CFRP skin. Highlights The erosion mechanism of plastic abrasive is semi-ductile erosion. Compared with manual sanding, PAJM is more suitable for carbon fiber-reinforced plastic (CFRP) substrates pretreatment. The proper PAJM process can realize the non-destructive CFRP substrate. Obtained the best pretreatment process