Lathe Operations

Lathe Operations

Numerical Control • CNC or Computer Numerical Control is a term derived from NC or Numerical Control.

• NC refers to Control of a process or automatic operation of a machine by using symbolic codes consisting of characters and numbers.

• NC was introduced in late 40’s to control machine tools such as Drilling and Milling machines. One of the first applications of NC machine tool was in production of helicopter rotor blades and ship propellers.

CNC System

CNC Axes

+X

+Z

Motion Statements

G00 Linear Movement (rapid)G01 Linear Movement (feed)G02 Circular Movement (cw feed)G03 Circular Movement (ccw feed)

CNC Programming

CNC Axes

+X

+Z

35

25

Tool at (25, 35)

CNC Axes

+X

+Z

Tool at (25, 35)

G00 X0 Z35

G00 X0 Z0

CNC Programming

X

Z

CNC Programming

Initial Diameter = 10 mmFinal Diameter = 6 mm Depth of cut = 1 mmWidth of cut = 8 mm

G00 X4 Z1

G01 Z-8

G00 X4 Z1

G00 X 3

G01 Z-8

G00 X4 Z1

CNC machine tools & programmingPreparatory NC Codes

G00 Linear Movement (rapid)G01 Linear Movement (feed)G02 Circular Movement (cw)G03 Circular Movement (ccw)G70 Inch unitsG71 Metric unitsG90 Absolute dimensionsG91 incremental dimensions

CNC machine tools & programming

Miscellaneous NC Codes

M02 End of programM03 Clockwise rotation of spindleM04 Counter-clockwise rotation of spindleM05 Stop rotation of main spindleM07 Coolant onM09 Coolant off

CNC machine tools & programmingSample Program

N01 G71 G90 M03 M07N02 G00 X9 Z1N03 G01 Z-25N04 G00 X10 Z1N05 G00 X8 Z0N06 G01 X9 Z12N07 G00 X20 Z20N08 M05 M09

Programming for CNC machine tools

TWO APPROACHES

• Manual part programming• NC program generation from CAD models

CNC Programming

CNC Programming

CNC Programming

CNC Programming

CNC Programming

CNC Programming

Gouging

CNC Programming

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