Orthogonal and Oblique cutting

Pure orthogonal cutting

Causes of chip flow deviation

Restricted cutting edge

Effect of tool nose radius

Effect of inclination angle

Effective rake angle

Effects of oblique cutting chip flow deviates from orthogonal plane affects transverse force irrespective of Φ affects effective rake, hence forces affects chips cross section and shape force analysis becomes complex affects tool life

Mechanism of chip formation in machining ductile materilas

Mechanism of chip formation in machining brittle materials

Orthogonal machining

Kronenberg’s model

Cutting strain

Built-up-edge formation

Characteristics of BUE

Need and purpose of chip-breaking Principles of chip-breaking

Self breaking of chips

Forced chip breaking

Parallel step type in-built chip breaker

Chip breakers in solid HSS tools

Cutting force component

Cutting forces in drilling

Cutting forces in milling

Merchant circle diagram

For brittle material

For ductile materials

Friction force and normal force

Relationship between velocities V = Cutting velocity Vs = Shear velocity Vc = Chip velocity

Question: In an orthogonal cutting test with a tool of rake angle 10º, the following observations were made: Chip-thickness ratio = 0.3 Horizontal component of the cutting force = 1290 N Vertical component of the cutting force = 1650 N From the Merchant’s theory, calculate the various components of the cutting forces and the coefficient of friction at the chip-tool interface. Ans: F = 1848.94 N N = 983.88 N µ = 1.8792 β = 62° R = 2049.42 N Fs = 740.63 N Ns = 1959.10 N

Measurement of cutting forces

Turning dynamometer

Drilling dynamometer

Milling dynamometer

Grinding dynamometer