Introduction To Cnc Programming

A.M.Wankhade,

Lecturer, Mechanical Engineering Department, JDIET.

Screen that appears on double clicking the icon

The Screen that appears on clicking the first screen

The screen that appears on selecting lathe machine

Screen for Load-Unload arm of lathe

The screen that appears on selecting mill machine

Screen for shuttle conveyor

Screen for Robot

Screen for ASRS

Screen for ASRS

Screen for the complete auto sequence

Initial User interface for turn or mill machine

Simulation window and editor window

Simulation

Changing the GUI from one machine to the other

GUI for milling machine

CNC Programming

Definition : Part program is a set of instructions which instructs the machine tool about the processing steps to be performed for the manufacture of a component. Part programming is the procedure by which the sequence of processing steps and other related data, to be performed on the CNC machine is planned and documented.

NC Word : A combination of binary digits(bits) in a row

denotes a character. A NC word is a collection of characters used to

form an instruction. A collection of NC words is called a block and a

block of words is a complete instruction.

Some typical NC Words : N-Word (Sequence Number) : The first word in every block is the sequence number. The sequence number is used to identify the block. The sequence number is preceded by word N and is written as N001, N005, etc.

G-Word (Preparatory Function) : The preparatory word prepares the control unit to execute the instructions that are to follow. The preparatory word is represented by two digits preceded by G. Following are some of the most commonly used G words : G00 : Rapid Traverse G01 : Linear movement with feed rate G02 : Circular interpolation (Clockwise)

Clockwise) G04 : Dwell G20 : Inch mode input G21 : Metric mode input G28 : Return to reference point or home position G40 : Cutter compensation cancel G41 : Cutter compensation left

G42 : Cutter compensation right G70 to G89 : Canned cycles G90 : Absolute coordinate system G91 : Incremental coordinate system G94 : Feed rate mm/min G95 : feed rate mm/rev

M Word (Miscellaneous function): This word is used to specify certain miscellaneous or auxiliary functions which do not relate to the dimensional movements of the machine. The M word is represented by two digits preceded by M. Following are some of the most commonly used M words : M02 : Program stop M03 : Spindle start (CW) M04 : Spindle start (CCW)

M05 : Spindle stop M06 : Tool change M08 : Coolant ON M09 : Coolant OFF M10 : Vice open M11 : Vice close M30 : Program stop and rewind

M62 : Output 1 ON M63 : Output 2 ON M64 : Output 1 OFF M65 : Output 2 OFF M98 : Subroutine call M99 : Subroutine End F Word (Feed Function) : This word is used to specify the feed rate.

S Word (Speed Function) : The spindle speed is specified using this word. T Word (Tool selection function) : T word is needed only for machines having ATC. Coordinate Word ( X, Y, Z) These words give the final coordinate positions for X, Y, and Z axis motions. EOB (End of block) : The EOB symbol identifies the end of instruction block.

Programming Formats : Format is the method of writing the words in a block of instruction. There are three programming formats used for part programming. 1.Fixed block format. 2.Tab sequential format 3.Word address format