A mechanistic approach to investigate drilling of UD-CFRP laminates with PCD drills

Carbon fiber reinforced plastics (CFRPs) possess desirable material properties that satisfy the aerospace industryʹs high strength to weight ratio objective. Therefore, CFRPs are commonly used in structural parts, either alone or together with aluminum and titanium alloys. Drilling of CFRPs has been studied extensively in the literature in recent years, with special emphasis on process parameters and delamination. This study identifies mechanical properties of uni-directional CFRPs through drilling tests. Drilling of uni-directional CFRP plates with and without pilot holes has been performed, and cutting and edge force coefficients are identified. A polycrystalline diamond (PCD) drill was used in tests since this type of drill is commonly used in practice. Finally, validation tests on multi directional CFRP laminates have been performed and good results have been obtained.