Study of thrust forces and delamination in drilling carbon-reinforced plastics (CFRPs) using a tapered drill-reamer

Abstract

The thrust forces and delamination in drilling carbon-reinforced plastics (CFRPs) using a tapered drillreamer have been studied by experimental and theoretical analyses. A theoretical drilling model of the tapered drillreamer has been established to study the developing process of the push-out delamination, and a comprehensive analysis for the thrust force and the delamination has been developed in the present study. The results obtained in this study show that the maximum thrust force measured in the drilling stage (F z1max ) is drastically affected by the machining parameters (spindle speed and feed rate). However, the maximum thrust force measured in the reaming stage (F z2max ) is not sensitive to the machining parameters, and the multiple N between F z1max and F z2max increases with the increase of feed rate but decreases with the increased spindle speed. Moreover, according to the theoretical drilling model, the thrust force thresholds at the onset and the propagation of delamination in the reaming stage are 29.57 and 51.34 N, respectively. In order to improve the hole quality, the length of the cutting edges of the tapered drill-reamer should be about 9.6 mm, and the improved drilling method of placing two rigid plates on both sides of CFRPs workpiece is preferred.

Comparative analysis of wobble milling, helical milling and conventional drilling of CFRPs

“…Abrão et al [57] showed that 56% of the tools used for drilling polymer composites have a special geometry. Some of the special drilling tools developed for CFRP cutting are as follows: (i) double point angle twist drills [58][59][60][61][62][63][64], (ii) brad and spur drills [21,[65][66][67][68][69][70], (iii) dagger drills (one-shot drills) [28,31,[67][68][69][70][71][72][73], (iv) step drills [67,68,[74][75][76][77][78][79][80], (v) core drills [81,82] and (vi) special core drills [83][84][85]. These special drilling tools are reviewed and discussed in detail by Geier et al [55].…”

Review on the methodologies adopted to minimize the material damages in drilling of carbon fiber reinforced plastic composites

“…In FRP/metal stack arrangement application, metal stack such as aluminum or titanium stack acts as a backup support plate to prevent delamination and bending deformation commonly. Many researchers reported about backup support and two-sided support with and without pre-drilled plates/fixtures 9,10,18,21,33,36,40,42,45,46 as a basic methodology to prevent delamination and bending of multimaterial during their studies of drilling of laminate composite material with other various methodologies and strategies of drilling.…”

On the Machining Temperature and Hole Quality of CFRP Laminates When Using Diamond-Coated Special Drills

“…To address the drilling issues of CFRPs, a large amount of research work has been carried out worldwide by scholars [10,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35], covering a variety of aspects involving drilling forces, drilling-induced damages, tool wear, etc. Some drilling-induced damage, including delamination, hole dimensional inaccuracy, surface roughness, fiber pullouts, and uncut fibers, have been investigated in the scientific literature [19,20].…”

“…It was found that the fiber cutting modes changed dynamically with the composite sequence, and the local feed forces generated on the hole bottom could be correlated with the delaminating aspects. Su et al [28] addressed the thrust forces and delamination issues when drilling CFRPs using a tapered drill-reamer and found that the drilling parameters significantly affected the maximum thrust force measured in the drilling stage instead of the reaming stage. Ameur et al [29] conducted drilling studies on CFRP materials using different types of tool materials.…”