MECH152-L23-1 (1.0) - 1 Metal Cutting MECH152-L23-1 (1.0) - 2 Metal Cutting Operations Turning Drilling Horizontal Milling Vertical Milling MECH152-L23-1 (1.0) - 3 Cutting Tools Single Point Cutter Multiple Point Cutter MECH152-L23-1 (1.0) - 4 Cutting Force Metal Removal Rate = vfd Cutting Force Metal Removal Rate MECH152-L23-1 (1.0) - 5 Cutting Mechanics Orthogonal Cutting Model Reducing the model to two dimensional model. Chip thickness ratio, r = t o / t c, always less than 1. t o = d, d being the depth of cut; t c is the chip thickness. l s = length of the shear plane MECH152-L23-1 (1.0) - 6 Cutting Mechanics MECH152-L23-1 (1.0) - 7 Cutting Mechanics Forces on chip Tool forces: Normal force, N; Frictional force, F = N; = tan Shear plane forces: Shear force, F s ; Normal force, F n Shear stress on shear plane: = F s /A s ; A s = t o w/sin A s = Shear plane area. MECH152-L23-1 (1.0) - 8 Cutting Mechanics F = F c sin + F t cos F = F c cos - F t sin F s = F c sin - F t co F n = F c sin + F t cos F c = cutting force F t = thrust force MECH152-L23-1 (1.0) - 9 Power & Energy Power, P = F c v Unit power, U = Specific energy = Power / Material Removal Rate = P / MRR = F c v / (vt o w) = F c / (t o w) MECH152-L23-1 (1.0) - 10 Power & Energy MECH152-L23-1 (1.0) - 11 Size Effect Correction MECH152-L23-1 (1.0) - 12 Temperature Rise in temperature at tool chip interface, or, in general