On the interpretation of drilling CFRP/Ti6Al4V stacks using the orthogonal cutting method: Chip removal mode and subsurface damage formation

A New Cutting Device Design to Study the Orthogonal Cutting of CFRP Laminates at Different Cutting Speeds

“…Both damages are generated mainly by the load instabilities due to the compressive loads (thrust force component) on the machining, which produce interlaminar delamination. Interlaminar delamination is far more critical in the external plies, where there is no backup laminate, and this effect was already highlighted and described by Xu et al [38]. Figure 6; Figure 7 show images of the tested materials, corresponding to 2 perpendicular planes of the machined surface for the tests at cutting speeds of 1 m/min and 200 m/min, and feeds of 0.05 mm and 0.2 mm, for the two tested cutting tools.…”

A Review on the Machinability of Aerospace-Grade CFRP/Titanium Stacks

“…3. In contrast, cutting from the titanium to the composite is confirmed beneficial for the metallic chip evacuation and hence the improvement of the stack hole quality [9,29,30]. However, such findings are contrary to the observation of the stack orthogonal cutting.…”

“…As shown in Fig. 8, the CFRP → Ti drilling induces severe composite surface damage close to the interface zone due to the scratching effects of the titanium chip evacuation [29]. By contrast, the interface damage promoted in the Ti → CFRP drilling sequence is limited owing to the avoided effects of the metallic chip ejection.…”

“…This means that the machining mechanisms of the stacks cannot be simply considered as the combination of the chip removal modes for the individual composite and titanium phases, particularly for the drilling operation. To understand the operating cutting mechanisms of CFRP/Ti stacks, Xu and his co-authors [15,29,46,[49][50][51][52][53] have sought to utilize the orthogonal cutting method to inspect the chip separation modes governing the machining of these composite-metallic stacks. In their work, both the experimental observations and the numerical simulations were adopted to reveal the underlying mechanisms of the stack chip formation process.…”

“…As such, machining of these multilayer stacks with desired quality has been a challenging task in the modern aerospace community. Particular issues arise from the inferior surface quality leading to the large proportion of part rejections and the rapid tool wear leading to the short tool life as well as high costs [26][27][28][29][30].…”