Drilling of carbon composites using a one shot drill bit. Part I: Five stage representation of drilling and factors affecting maximum force and torque

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

“…The drilling process of CFRPs using a tapered drill-reamer were divided into five stages, namely, stage I entrance, stage II drilling, stage III drilling and reaming, stage IV reaming, and stage V backing out, according to the measured thrust forces by Fernandes et al [19]. For the convenience of the analysis of the machining process and the thrust-time curves, the five stages were simplified to three main stages, namely, stage I drilling (from starting cutting to the cutting edges of the primary region completely entering), stage II drilling and reaming (from the drill point starting backing out to the cutting edges of the secondary region beginning reaming), and stage III reaming (from the cutting edges of the secondary region beginning reaming to entirely backing out).…”

“…The reaming stage was the final stage, so the thrust force of the reaming stage was the most significant factor affecting the delamination of the finished hole, and the tool tip would be worn rapidly due to the large thrust force of the drilling stage. So the thrust forces of every stage were very significant to the hole quality and the drill life [19]. Therefore, it can be noted that the study on the variation rules of F z1max and F z2max has a certain guiding significance on how to improve the machining performance of this type of drill bit and on how to reduce the drillinginduced damages.…”

“…Therefore, the tapered drill-reamer has been widely used, and the research on the tapered drill-reamer has been conducted. Fernandes et al [19] studied on drilling differing-thickness carbon-epoxy composite laminates using the one-shot drill bit, in which the thrust forces and torques were investigated. Based on the measured thrust force, the drilling process was divided into five drilling stages, and the common problems and defects associated with each stage were also discussed.…”

Prediction of forces during drilling of composite laminates using artificial neural network: A new approach

“…It was found that the core drill offers the highest critical feed rate followed by candle stick drill, saw drill, step drill and the traditional twist drill. The mathematical models to predict the thrust force, torque and delamination during drilling of composite laminates have also been developed [21,22]. Various predictive models have been developed, but the need of the hour is to develop more generic models is an area of paramount importance.…”

Drilling of Glass Fiber-Reinforced Epoxy Laminates with Natural Fillers: Thrust Force Analysis

“…The effect of diameter ratio was relatively insignificant. Fernandesa and Cook (2006) developed a mathematical model of the maximum thrust force and torque during drilling of carbon fiber using a 'one-shot' drill bit. Khashaba (2004) found that the delamination size was increased with increasing feed rate as a result of increasing thrust force.…”