Tool wear in friction drilling

This study investigates the tool wear in friction drilling, a nontraditional hole-making process. In friction drilling, a rotating conical tool uses the heat generated by friction to soften and penetrate a thin workpiece and create a bushing without generating chips. The wear of a conical tungsten carbide tool used for friction drilling a low carbon steel workpiece is studied. Tool wear characteristics are quantified by measuring its weight change, detecting changes in its shape with a coordinate measuring machine, and making observations of wear damage using scanning electron microscopy. Energy dispersive spectrometry is applied to analyze the change in chemical composition of the tool surface due to drilling. In addition, the thrust force and torque during drilling and the hole size are measured periodically to monitor the effects of tool wear. Results indicate that the carbide tool is durable, showing minimal tool wear after drilling 11,000 holes, but observations also indicate the progressively severe abrasive grooving on the tool tip. (C) 2006 Elsevier Ltd. All rights reserved.