Analysis of damage mechanism and tool wear while drilling of 3D woven composite materials using internal and external cutting fluid

The aim of this paper is to study the influence of machining parameters and lubrication modes on the mechanisms of damage and tool wear when drilling a new 3D woven composite material used in carter fan of aircraft engine. The composite specimens are drilled using a diamond-coated carbide three lips twist drill (3LTD). The wear mechanisms are quantified in function of the number of drilled holes using microscopy. The results have shown that the feed and the mode of lubrication are the main factors for the initiation of the first damage, which appears on the wall of the hole. The results have also shown that for any mode of lubrication, no delamination is observed at the exit of the hole even at high feed (0.3 mm/rev). This is attributed to the out-of-plane reinforcement of the 3D woven composite material. Moreover, tool wear mechanisms are found proportional to the distance covered by the tool tip and are driven by abrasion phenomenon on the flank face. It is also found that the spindle speed does not have any impact on the tool life.