Influence of Cutting Edge Preparation on Tool Wear of Cemented Carbide Drills on AISI P20 Steel

Drill life constitutes a critical parameter within the machining process, given its importance when dealing with the demand for high productivity and reduced process times. With regard to the cutting tool microgeometry, the condition significantly impacts the performance and its reliability. Therefore, the aim of this study was to verify the influence that cutting edge preparation has on the wear behavior and tool life of cemented carbide drills when machining AISI P20 steel. To this purpose, experimental tests were carried out on drills that maintained the microgeometry resulting from the manufacturing process, and on drills that were prepared by the brushing-polishing process. The tools were characterized using a stereoscope, scanning electron microscopy and a 3D optical measurement. Experimental results show that cutting edge preparation was effective in increasing the radius by 120% of the original value. The brushing-polishing process was capable of removing the previous defects and generated a homogeneous microtopography, verified by the average reduction of 30% in the surface roughness. This directly impacted the wear behavior, since the tool exhibited less wear during the process. In addition, wear mechanisms were also adequately controlled. For these reasons, the brushing-polishing process increased the life of the drill by 50% while maintaining the same flank wear.