Cutting Tools
HISTORY OF CUTTING TOOL MATERIALS
• Cutting tool used during the industrial revolution in 1800 A.D
• First cutting tool was cast using crucible method (1740) and slight hardened by H.T.
• 1868: R. Mushet found by adding Tungsten we can increase hardness and tool life ( Air Quenching)
• F.W.Taylor in Pennsylvania did the most basic research in metal cutting between 1880-1905
• Invented high speed steel (better H.T. process)
• Better alloy
• Tungsten Carbide was first synthesized in 1890.
• Took 3 decades before we got Cemented carbide.
• First used in Germany.
• Sintering technology was invented.
Cutting Tool Geometry Angle Definitions
• Top Rake: Evacuates chip…rolls chip out
• Heel or Clearance Angle: This is the clearance between the cutter and the surface that has just been cut. Insures that the cutting edge (and not the back side or heel of the cutter) contacts the work piece first
• Lead Angle: This is formed by the leading edge of the cutter and a plane perpendicular to the cutter feed motion
• End relief angle: The clearance below the end of the tool
• Side Relief Angle: The clearance below the cutting edge
• Back Rake: This is a shear angle that also evacuates the chip or rolls the chip out
• Nose Radius: The nose radius stretches the cutting edge. It increases the amount of cutting edge in contact with the work
Heel Angle (Positive): A small positive heel angle provides a stronger cutting edge and minimizes tool chatter.
Heel Angle (Negative): A zero or negative heel angle will cause the tool to drag on the work piece material and prevents the tool from entering. Heel Angle (large positive) : A larger positive heel angle provides a keener cutting edge that will penetrate the work piece more readily, but gives the tool a
• Cutting tool used during the industrial revolution in 1800 A.D
• First cutting tool was cast using crucible method (1740) and slight hardened by H.T.
• 1868: R. Mushet found by adding Tungsten we can increase hardness and tool life ( Air Quenching)
• F.W.Taylor in Pennsylvania did the most basic research in metal cutting between 1880-1905
• Invented high speed steel (better H.T. process)
• Better alloy
• Tungsten Carbide was first synthesized in 1890.
• Took 3 decades before we got Cemented carbide.
• First used in Germany.
• Sintering technology was invented.
Cutting Tool Geometry Angle Definitions
• Top Rake: Evacuates chip…rolls chip out
• Heel or Clearance Angle: This is the clearance between the cutter and the surface that has just been cut. Insures that the cutting edge (and not the back side or heel of the cutter) contacts the work piece first
• Lead Angle: This is formed by the leading edge of the cutter and a plane perpendicular to the cutter feed motion
• End relief angle: The clearance below the end of the tool
• Side Relief Angle: The clearance below the cutting edge
• Back Rake: This is a shear angle that also evacuates the chip or rolls the chip out
• Nose Radius: The nose radius stretches the cutting edge. It increases the amount of cutting edge in contact with the work
Heel Angle (Positive): A small positive heel angle provides a stronger cutting edge and minimizes tool chatter.
Heel Angle (Negative): A zero or negative heel angle will cause the tool to drag on the work piece material and prevents the tool from entering. Heel Angle (large positive) : A larger positive heel angle provides a keener cutting edge that will penetrate the work piece more readily, but gives the tool a