CNC MACHINE

3.  1955 - US Air Force define a need to develop a machine tool capable of
machining complex and close tolerance aircraft parts.
 1959 - MIT is the contractor and builds the machine for the project. MIT
announces Automatic Programmed Tools (APT) programming language
 1960 - Direct Numerical Control (DNC). This eliminates paper tape and allows
programmers to send files directly to machine tools
 1980’s - CNC machine is introduced. Unix and PC based systems
 1997 - PC-Windows operating system is attached to cnc

4.  Turning Centers
 Milling Centers
 Vertical Machining Centers
 Horizontal Machining Centers
 Drilling Machines
 EDM Machines
 Laser-Cutting Machines

8.  Spindle in a vertical orientation.
 VMCs are high-precision
 Used for tight-tolerance

10.  Spindle in a horizontal orientation.
 Horizontal orientation encourages
chips to fall away.
 HMCs are high-precision
 Used for tight-tolerance

11.  Controlled by G and M codes.
 These are number values and co-ordinates.
 Each number or code is assigned to a particular operation.
 Typed in manually to CAD by machine operators.
 G & M codes are automatically generated by the computer
software.

13.  O - Program number
 N - Sequence number
 G - Preparatory function
 X - X axis designation
 Y - Y axis designation
 Z - Z axis designation
 R - Radius designation
 F – Feed rate designation
 S - Spindle speed designation
 H - Tool length offset designation
 D - Tool radius offset designation
 T - Tool Designation
 M - Miscellaneous function

14.  G00 Rapid Transverse
 G01 Linear Interpolation
 G02 Circular Interpolation, CW
 G03 Circular Interpolation, CCW
 G20/G70 Inch units
 G8 Cancel canned cycles
 G81 Drilling cycle
 G82 Counter boring cycle
 G83 Deep hole drilling cycle
 G90 Absolute positioning
 G91 Incremental positioning

15.  M00 Program stop
 M01 Optional program stop
 M02 Program end
 M03 Spindle on clockwise
 M04 Spindle on counterclockwise
 M05 Spindle stop
 M06 Tool change
 M08 Coolant on
 M09 Coolant off
 M10 Clamps on
 M11 Clamps off
 M30 Program stop, reset to start

17. CNC machine manufactures this items
Automobile Part
Aerospace

18. Diamond & Jewellery Ind.
Textile Machinery
Die & Mould Manufactures

20. • Posess hardness and strength at high
temperatures
• Able to withstand when heat is
generate
• Angle of the cutting face
• Flute width, number of flutes, teeth,
and margin size

21.  Lubricating during cutting process
 Cooling the workpiece at high cutting speeds
 Improving tool life,
 Improving surface finish
 Flushing away chips from the cutting zone
 Corrosion protection of the machined surface

22.  STRAIGHT OILS -Non-emulsifiable and are used in machining operations in an
undiluted form they are composed of a petroleum oil , lubricants such as fats, vegetable oils
( BEST LUBRICATION )
 SOLUBLE OILS -Contain no petroleum or mineral oil , composed of
alkaline inorganic and organic compounds ( BEST COOLING )
 SEMISYNTHETIC FLUIDS- Emulsion when mixed with water
( LEAST EXPENSIVE )
 SYNTHETIC FLUIDS-Combination of synthetic and soluble oil fluids
( COST AND HEAT TRANSFER PERFORMANCE )

23.  High Accuracy e.g. Aircraft parts
 Production rate is very high
 Complex surfaces need to be machined
 Flexibility in job change , automatic tool settings
 More safe , higher productivity , better quality
 Less paper work , faster prototype production

24.  Costly setup
 Skilled operators
 Computers , Programming knowledge required
 Maintenance is very difficult

25. .