Search

a b s t r a c t In this study, an experimental investigation on the drilling of unidirectional carbon fiber reinforced plastic (UD-CFRP) composite was conducted using polycrystalline diamond (PCD) tipped eight facet drill. The quality of the drilled hole surface was examined through surface roughness measurements and surface damage by scanning electron microscopy (SEM). It was found that fiber pullout occurred in two specific sectors relative to the angle between the cutting direction and the fiber orientation. The thrust force was highly influenced by the feed rate than the cutting speed and it shows a significant variation throughout the rotation of the drill.

The condition of the cutting tool when drilling composite materials is the controlling factor for the surface integrity of hole produced. The high rate of tool wear when drilling composite materials makes finding a way to monitor the condition of the cutting tool without interrupting the drilling process a great necessity. Inspecting the condition of the drill between or during the drilling process is not practical or economical. In an attempt to tackle this problem, a new approach of on-line tool wear monitoring method using an air-coupled audio microphone is proposed. An experimental investigation was conducted on multi-directional carbon fiber reinforced plastic (CFRP) composite material using a high speed steel (HSS) drill. The result shows that, the amplitude of the acoustic signal from the microphone decreases when the amount of flank wear increases and the amplitude of thrust force and torque increases with the increase of the flank wear. This result demonstrates that the proposed approach can be used as an effective and economical tool for on-line monitoring of cutting tool condition.

The quality of the hole produced during the drilling of composite materials is one of the controlling factors for the resulting joint strength and integrity of the structural component. Quality of the hole depends on the condition of the cutting tool. Continuous cutting tool condition monitoring method is vital to accomplish the desired hole quality. To address this concern, an online tool condition monitoring technique using a simple audio microphone as a sensor is developed and Recurrence Quantification Analysis (RQA) methodology was used as a signal analysis tool to predict the tool condition in terms of flank wear. A series of experimental drilling operation was carried out on uni-directional carbon fiber reinforced plastic (CFRP) composite. It was found that the amplitude of the microphone signal decreases with the increase of the tool flank wear. In addition, from the selected eight RQA output variables, six of them show an increasing trend with the increase of the measured flank wear, whereas, two of them show a decreasing trend with the increase of tool wear. The same trend has been observed in both set of experiments. These results demonstrate that, this novel approach is an effective and economical online tool condition monitoring method.

The effect of surface ply on the quality of the hole produced when drilling multi-directional carbon fiber reinforced plastic (CFRP) composite laminates was investigated. A series of drilling experiments are performed using a carbide drill tool on two multi-directional CFRP composite laminates. The two composite laminates have similar stacking sequence except the surface plies, namely woven fabric and fiberglass scrim. The thrust force and torque was collected during the drilling process. The quality of the drilled hole was examined through surface roughness measurement, fiber pull out, and delamination. Thrust force was found to be higher for the composite laminate with woven fabric surface plies. The exit delamination factor measured from the holes with woven fabric surface plies found to be lower than the holes with fiberglass scrim surface plies.

In this study, an experimental investigation on the drilling of unidirectional carbon fiber reinforced plastic (UD-CFRP) composite was conducted using polycrystalline diamond (PCD) tipped eight facet drill. The quality of the drilled hole surface was examined through surface roughness measurements and surface damage by scanning electron microscopy (SEM). It was found that, fiber pullout occurred in two specific sectors relative to the angle between the cutting direction and the fiber orientation. The thrust force was highly influenced by the feed rate than the cutting speed and it shows a significant variation throughout the rotation of the drill.Copyright © 2012 by ASME