Abstract
The differences in the cutting speed are a serious problem along the cutting edge of the drill, in drilling operations. This problem can partly be solved reducing the length of the cutting edge via changing the drill point angle. In addition, in this study, the effect of point angle, feed rate, and cutting speed on drilling is investigated. For identifying the optimum cutting parameters, AISI 1050 steel alloy was selected as the experimental specimen, these specimen were pre-drilled 5 mm in diameter due to eliminating the effect of the chisel edge. In the experiments, the holes were drilled only at a depth of 10 mm in order not to give any harm to the dynamometer while measuring thrust force. For this aim, in drilling process, drills with point angle of 100°, 118°, 136°, 154°, and 172° were selected. In conclusion, the thrust force, the tool wear, and the surface roughness linearly decreased with increasing point angles due to less removal chip area, in per revolve of the tool. However, the thrust force, the tool wear, and the surface roughness were adversely affected at higher feed rates and lower cutting speeds. The hole dimensional accuracy decreased at lower feed rates and cutting speeds but at higher point angles and concurrently at higher feed rates but lower point angles and cutting speeds. However, the hole dimensional accuracy showed more decisiveness at 118° than other point angles, while the highest dimensional accuracy values recorded at 136° point angle, at higher cutting speeds.
Highlights
Drilling is a manufacturing process that provides desirable geometrical and dimensional accuracy in the product of machine parts, for installation processes, as well.1 It is including approximately 33% of all metal cutting operations
The cutting forces have important effects on tool life and surface quality, its magnitude depends on the cutting tool geometry; tool material; the properties of the machined samples; and machining parameters like cutting speed, feed rate, and undeformed chip thickness
Because of the geometry of the drills, especially the point angle of the drill, providing the cutting edge a taper angle, the cutting speed has a variation along the cutting edge
Summary
Drilling is a manufacturing process that provides desirable geometrical and dimensional accuracy in the product of machine parts, for installation processes, as well. It is including approximately 33% of all metal cutting operations. Drilling is a manufacturing process that provides desirable geometrical and dimensional accuracy in the product of machine parts, for installation processes, as well.. Drilling is a manufacturing process that provides desirable geometrical and dimensional accuracy in the product of machine parts, for installation processes, as well.1 It is including approximately 33% of all metal cutting operations. While increases in feed rate forms the rough surface of the drilled hole, higher spindle speeds, and point angles produce better surface finish due to the reduced thrust force and in this way by providing the minimum tool wear.. The thrust force, decreasing with increases in both the point and helix angles, in drilling operations, is an important parameter to affect the results, such as surface roughness, hole diameter deviation, and burr height. While increases in feed rate forms the rough surface of the drilled hole, higher spindle speeds, and point angles produce better surface finish due to the reduced thrust force and in this way by providing the minimum tool wear. The number of the drilled holes is the most considerable factor affecting the wear rate, as well. The thrust force, decreasing with increases in both the point and helix angles, in drilling operations, is an important parameter to affect the results, such as surface roughness, hole diameter deviation, and burr height.
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