1 – processed surface, 2 – cutting surface, 3 – finished surface METAL CUTTING Metal cutting, or machining, is a process of cutting off a layer of metal from a work-piece surface in the form of chips by the cutting tool in order to obtain the necessary geometry, size accuracy, and surface finish of a part. Schemes of machining: 1 – processed surface, 2 – cutting surface, 3 – finished surface

METAL CUTTING Physical phenomena in the cutting process a b c Formation of chips Types of chips: а – continuous chips (plastic metals); b – chips of chopping off (metals having medium hardness); c – element (brittle metals) a b c Sources of heat generation and heat distribution upon cutting The equation of the thermal balance of a cutting process: Q1 + Q2 + Q3 = Qch + Qtool + Qw-p + Qrad. From a cutting zone heat is removed with chips (25–85 %), absorbed by the work-piece (10–50 %) and the tool (2–8 %).

Turning machine, or lathe: METAL CUTTING Machining by lathe Turning machine, or lathe: 1 – bed; 2 – gear box; 3 – quick-change gear box; 4 – headstock with gear box and spindle; 5 – three-jaw chuck; 6 – carriage; 7 – tool post; 8 – cross slide; 9 – tailstock; 10 – tail cabinet base; 11 – apron; 12 – head cabinet base Turning cutters: 1 – side cutter; 2 – facing cutter; 3 – groove cutter; 4 – strait turning cutter; 5 – left-hand facing cutter; 6 – thread cutter; 7 - parting cutter

METAL CUTTING Machining by grinding V = ·Dw·n / (103∙60), m/s, Speed of cutting for grinding is defined by the formula V = ·Dw·n / (103∙60), m/s, where Dw – external diameter of a wheel, mm; n – frequency of wheel rotation in rpm. Circular grinding: 1 – grinding wheel; 2 – work-piece; 3 – driver chuck; 4 – carrier; 5 – tail centre Internal grinding

METAL CUTTING Machining by drilling Twist drill Core drill Drilling machine tool Core drill