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Crater wear occurs on rake face of tool, while flank wear occurs on relief (flank) face of tool.

Since n = 0.5, Taylor equation can be rewritten as VT^0.5 = 120.

Let’s denote V₁ as initial speed and V₂ reduced speed; thus, V₂ = 0.5 V₁. Because C is constant 120, we have relationship
0.5V₁ sqrt T₂ = V₁sqrt T₁

Simplifying this equation, T₂/T₁ = 1/0.25 = 4. This
indicates that change in tool life is
(T₂ – T₁/ T₁) = (T₂/T₁) – 1 = 4 – 1 = 3,

or that tool life is increased by 300%. Thus, a reduction in cutting speed has resulted in a major increase in tool life. Note also that, for this problem, magnitude of C is not relevant.

Discontinuous chips are formed during machining of brittle metals while continuous chips are formed during machining of ductile materials.

In metal machining, zone where maximum heat is generated due to plastic deformation of metal, is called shear zone while zone where heat is generated due to friction between moving chip and tool face, is called friction zone.

Discontinuous chips are formed during machining of brittle metals while continuous chips are formed during machining of ductile materials.

To find a shear angle in continuous chip feed, rake angle, chip thickness, cutting ratio are required.

Flank wear occurs as a result of friction between progressively increasing contact area on tool flank.

When machining ductile materials, conditions of high local temperature and extreme pressure in cutting zone and also high friction in tool chip interface, may cause work material to adhere or weld to cutting edge of tool forming built-up edge. Low-cutting speed contributes to formation of built-up edge. Increasing cutting speed, increasing rake angle and using a cutting fluid contribute to reduction or elimination of built-up edge.

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