Study On Automatic Hole-making Technology Of CFRP/Ti-6Al-4V Stacked Wing

The single-side fixed connection holes of wing of CFRP/Ti-6A1-4V stacked structure are key parts in integral panel components assembly.Their quality and accuracy have important influence on the assembly reliability of whole aircraft.To obtain those holes,via holes are made in the laminated structure formed by panel and internal skeleton.Hole reaming and dimpling oval fossa are accomplished orderly in the via holes of internal skeleton after withdrawing panel.Traditional processing methods including drilling,reaming and oval fossa dimpled by hand have poor quality and low efficiency,which can’t meet requirements of hole-making in integrated wing assembly.The technologies of orbital drilling of carbon fiber reinforced plastics(CFRP)and Ti-6A1-4V stacked structure and dimpling oval fossa in the Ti-6A1-4V hole were studied in this paper to make the single-side fixed connection holes.To ensure those studies were conducted successfully,an innovative system with multifunction end-effector were established.During orbital drilling of carbon fiber reinforced plastics(CFRP)and Ti-6A1-4V stacked structure,the composite wall of hole was damaged by Ti-6Al-4V chips.In this paper,a strategy was proposed to proceed the secondary fine processing when the cutting tool returned by fully taking advantage of eccentricity machining feature of orbital drilling.The resultant optimized machining parameters were determined by conducting orthogonal experiments.The experiment results show that optimized return machining process can only improve hole quality of CFRP and Ti-6A1-4V stacked structure greatly,but not the hole accuracy.In order to improve the hole accuracy of orbital drilling of CFRP and Ti-6A1-4V stacked structure,an off-line neural network model of radial force-aperture error was established based on the improvement processing.The aperture error of CFRP and Ti-6A1-4V stacked materials was corrected using on-line compensation method.The results show that the accuracy of the holes can reach H9 level after using V above-mentioned compensation strategy.To dimple oval fossa in the Ti-6A1-4V hole successfully,the automatic drilling Technology of oval hole was studied in this paper.During the research,the formula of the center of the elliptical sway was constructed,and the error sources which caused oval hole defect were analyzed comprehensively.To avoid these oval hole defect,an error mitigation method based on measuring the size of oval hole was proposed.The experiment results show that the size of the oval hole is ideal and the surface roughness can reach Ra0.8 after using above-mentioned error mitigation method,which meets the requirements of integrated wing assembly.