Types of Chips

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Types of Chips

• Continuous
• Built up edge
• Serrated
• discontinuous

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Continuous chips

• Usually formed at high cutting speed or high rake
  angle
• Primary shear zone
• Sometimes secondary sear zone
• Wide primary shear zone can occur

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Chip Breakers
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B.u.E. Chip

• Forms at the tip of the tool
• Plastic deformation causes adhesion between chip
  and tool face
• BE eventually gets unstable and is removed with
  the chip
• Adversely affects the surface finish
• Changes the geometry of cutting

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• Higher the strain hardening exponent, higher
  chance of BE.
• At high speed BE is not a problem
• To avoid BUE Decrease Depth of cut, increase
  rake angle, reduce tool tip radius, cutting fluid
• 3) Serrated Chips
• Segmented or non-homogenous chip
• 4) Discontinuous Chips
• Brittle w/p can not undergo shear strain
• Metal with hard inclusions and impurities.

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Discontinuous chips

• Very low or very high cutting speed
• Large depth of cut or low rake angle
• Low machine tool stiffness
• Generally non metals like ceramics, polymers,
  composites, form brittle discontinuous chips.

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• Oblique Cutting
• Cutting tool forms an angle i with the w/p.
• a n is called the normal rake angle
• a e is the effective rake angle

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• Chip flow angle
• We can measure i and a n. As i increases and a
  e increases chip becomes thinner and longer.
• Look at terminologies of a single point cutting
  tool.

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