The life of tool is affected by many factors, such as: Cutting speed, feed, depth of cut, chip thickness, tool geometry, cutting tool material and rigidity of the machine.
Cutting speed
Cutting speed has the greatest influence on tool life. As the cutting speed increases the temperature also rises. This heat is more concentrated on tool tip than on the work. This causes the tool tip to loose its hardness and thereby wear.
Feed and depth of cut
The tool life is influenced by the feed rate also. With a fine feed, the area of chip passing over the tool is greater than that of coarse feed and reduce tool life. For a constant tool life cutting speed decreases with the increase of feed and depth of cut.
Tool geometry
The tool life is also affected by the tool geometry. A tool with large rake angle becomes weak, as the large rake angle reduces the tool cross section and the amount of material to absorb the heat. It is suggested an optimum rake angle for maximum tool life.
Tool material
Physical and chemical properties of the tool material influence tool life by affecting rate of wear of tool.
Cutting fluid
Cutting fluids affect tool life to a greater extent. A cutting fluid not only carry away the heat generated at the tool tip but reduces the coefficient of friction at the tool chip interface and increases the tool life.
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