Unformatted text preview: l carbide
inserts in nickel-based materials.
• added benefit of the toughness of the SiC whiskers to make this
category of ceramic available for machining harder materials with
interruptions. Major Classes of Tool Materials
7. Polycrystalline Tools
Fabricated by compacting small particles of diamond or
polycrystalline diamond (PCD) under high pressure and temperature.
Polycrystalline tool materials are more homogeneous, with improved
strength and durability, but with slightly reduced hardness compared
to natural diamond.
PCD is less expensive
than diamond, but over 20
times more costly than
carbide. However, it has
up to 50 times longer tool
life than carbide. Major Classes of Tool Materials
8. Cubic Boron Nitride
Its hardness is 2nd to diamond and has high wear resistance.
Used for machining high temperature and hardened ferrous alloys
Available in solid CBN and as CBN-tipped tools (on carbide
Can cost 20 times that of carbide. Major Classes of Tool Materials
9. Diamond Tools
Diamond tools have diamond grains suitably fixed on the cutting
parts of the tool by a bonding material or another method.
For machining precision parts and non-ferrous alloys (Al) and
non-metallic materials (fibre glass and composites)
Not suitable - for machining carbon steel. Diamonds can react with
Fe, Co, Ni, Cr, V under the high temperatures generated in the
machining processes. Hence, diamond tools are not suitable to
machine steels, including common steels and various tough alloy
steels. Single crystal diamond cutting tool
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- Spring '13
- Diamond, Superhard materials, tool materials, carbide tools