CNC-PROGRAMMING-PART-2

7/29/2019 CNC-PROGRAMMING-PART-2

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TOPICS COVERED

WORK OFFSET,TOOL LENGTH OFFSETAND DIAMETER OFFSET

MOST COMMONLY USED

G & MCODES

G91 (INCREMENTAL) G90 (ABSOLUTE)PROGRAMMING

G00 AND G01

PLANE SELECTION REFERANCE POINT (2ND 3RD & 4TH )


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G & M CODES


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These are commands which prepare the

machine for different modes of movement like

positioning contouring, thread cutting etc.

The preparatory functions always precede the

dimension word.

G FUNCTIONS:


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G FUNCTIONS:

Type meaningOne shot G-code The G-code is effective only in the block

in which it is specified

Modal G-code The G-code is effective until anotherG-code of the same group is specified.

Example;

G01andG02are modal G-codesG01X____;

y____;

X____;

G00X____;

G01 is effective in

this range

Example;

G04 and G10

G04X____;

G10X____Y____Z____;

G10 is effective

only in this range


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CLICK TO SEE G CODES:


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G CODE GROUP FUNCTION

G00 POSITION (RAPID TRAVERSE)

G01 INEAR INTERPOLATION (FEED)

G02 01 CIRCULAR INTERPOLATION CW

G03 CIRCULAR INTERPOLATION CCW

G04 DWELL

G10 00 DATA SETTING

G11 DATA SETTING MODE CANCEL

G17 Xp Yp PLANE SELECTION

G18 02 Zp Xp PLANE SELECTION

G19 Yp Zp PLANE SELECTION


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G20 INPUT IN INCH

G21 06 INPU IN MM

G27 Return to reference posiiton check

G28 Return to reference posiiton

G29 Return from reference posiiton

G30 2nd 3rd &4th Return to reference posiiton

G31 00 Skip function

G33 01 Thread cutting


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G40 Cutter compensation cancel

G41 07 Cutter compensation left

G42 Cutter compensation right

G43 08 Tool length compensation +direction

G44 Tool length compensation direction

G49 Tool length compensation cancel

G52 00 Local coordinate systemselection

Machine coordinate system

selection

G53


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G54 14 work piece coordinate selection 1

G54.1 Additional work piece coordinateselection 1

G55 work piece coordinate selection 2




G60 00/01 Single direction positioning

G61 15 Exact stop mode

G62 Automatic corner overide

G63 Tapping modeG64 Cutting mode

G65 00 Macro call

G66 12 Macro modal call

G67 Macro modal call cancel


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G73 09` Peck drilling cycle

G74 Counter tapping cycle

G76

09 Fine boring cycle

G80 Canned cycle cance

G81 Drilling cycle/spot boring cycle

G82 Counter boring cycle

G83 09 peck drilling cycle

G84 Tapping cycle

G85 boring cycleG86 boring cycle

G87 Back boring cycle

G88 Boring cycle

G89 Boring cycle


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G90 03 Absolute command

G91 Increment command

G94 05 Feed per minute

G95 Feed per rotation

G96 13 Constant surface speed control

G97 Constant surface speed control cancel

G98 10 Return to initial point in canned cycle

G99 Return to R point in canned cycle


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BASIC M CODES

M functions :

This function pertains to auxiliary or

switching information, which does not relate

to dimensional movement of the machine,such as spindle command or coolant ON-

OFF & other functions.

Some of the miscellaneous functions are

defined by CNC system manufacturers and

some are defined by machine tool

manufacturers.

A list of M-functions are given below;


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CLICK TO SEE M CODES:


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M-CODES

M00 PROGRAM STOP

M01 OPTIONAL STOP

M02 PROGRAM END

M03 CW SPINDLE ROTATION

M04 CCW SPINDLE ROTATIONM05 SPINDLE STOP

M06 TOOL CHANGE CYCLE

M08 COOLANT PUMP ON

M09 COOLANT PUMP OFFM10 ROTARY TABLE UNCLAMP (4TH AXIS)

#-OPTIONAL FUNCTIONS.FOR DETAILS REFER THEMACHINE MANUFACTURES MANUAL


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M11 ROTARY TABLE CLAMP (4TH AXIS)

M19 SPINDLE ORINTATION STOP

M28 RIGID TAP MODE CANCEL

M29 RIGID TAP MODE CANCELM30 PROGRAM END AND REWIND

M36 COMPONENT LOAD CYCLE

M37 COMPONENT UNLOAD CYCLE

M43 DOOR CLLOSE

M44 DOOR OPENM48 SPINDLE OVERIDE ENABLE

M48 SPINDLE OVERIDE DISABLE

M55 JIG FLUSHING COOLANT

M65 IMAGE X AXIS

M66 IMAGE Y AXIS

M67 IMAGE 4TH AXIS

M68 IMAGE CANCEL


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M-CODES

M70 TOOL POCKET DOWNM71 DOUBLE ARM GRIPS TOOLS

M74 DOUBLE ARM ROTATES 1800

AND LOADS TOOLS

M76 SPINDLE TOOL CLAMPM77 ARM RETURN TO PARKING

POINT

M78 TOOL POCKET UP

M90 CLEAR TOOL DATA

M91 SET TOOL DATA


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G00 (POSITIONING) &G01 (LINEAR

INTERPOLATION)


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G00 (POSITIONING)

G00 COMMAND MOVES A TOOL TO

POSITION IN THE WORK PIECE

SYSTEM SPECIFIED WITH ABSOLUTEOR INCREMENTAL COMMAND AT A

RAPID TRAVERSE RATE.


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G01

(LINEAR INTERPOLATION) A TOOL MOOVES ALONG A LINE TO

SPECIFIED POSITION AT A FEED RATE

SPECIFIED IN FIN PART PROGRMME.

THE FEED RATE SPECIFIED IN F IS

EFFECIVE UNTIL NEW VALUE IS

SPECIFIED.IT NEED NOT BE SPECIFIED FOR

EACH BLOCK.


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G90 (ABSOLUTE) &

G91 (INCREAMENTAL)


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1. Abso lu te d imens ion ing sys tem (G90):

The system in which all the measurements are

taken from a fixed origin with coordinatesX=0, Y=0 and Z=0 is known as absolute

coordinate system.

This origin serves as a datum position from

which all the distances are measured parallel

to each axis of the system.

TYPES OF DIMENSIONING

SYSTEMS


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Absolute Dimensions

10

20

30

40

0,0


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2. Incremental d imens ion ing system (G91):The system in which all measurements

for the next position are calculated in

the forms of increments of distancefrom the point at which the slide is

resting presently.

Hence needs no predetermined datumpoint.

TYPES OF DIMENSIONING SYSTEMS


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Incremental Dimensions

1010 10 10

M hi


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(20.00) (20.00) (20.00)

(10.00)(10.00)

(10.00)

Machine

referance

Work

offset

Pos 1Pos 2

M hi


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(20.00) (20.00) (20.00)

(10.00)(10.00)

(10.00)

Machine

referance

Workoffset

Moove Tool from m/c ref to work offest on Rapid.

G00 G90 XO.O YO.O ZO.1 ;

a) Positioning

Positioning should be always programmed inabsolute mode for to avoid any changes in part

programme during set up change.

M hi


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(20.00) (20.00) (20.00)

(10.00)

(10.00)

(10.00)

Machine

referance

Work

offsetMove Tool from work zero To Pos no-1 and 2 in feed .

G00 G90 X 0 Y 0 Z 0 ;

G01 G91 X-20.0 Y10.0 F100.0 ;

G01 G91 X-20.0 Y10.0;

a)Incremental

programming

M hi


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(20.00) (20.00) (20.00)

(10.00)

(10.00)

(10.00)

Machine

referance

Work

offsetMoove Tool from work zero To Pos no-1 and 2 in feed

.

G00 G90 X0 Y0 Z0;

G1X-20.00 Y10.00 F100.0 ;

G1 X-40.0 Y20.0

a)Absolute

programming


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WORK OFFSET

WORK OFFSET


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WORK OFFSET(WORK COODRDINATE SYSTEM)

WORK OFFSET IS THE DISTANCE

BETWEEN MACHINE REF POINT

TO WORK ZERO (Ref point)

POSITION.

MACHINE REF


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(X0.0 Y0.0 Z0.0)

MACHINE REF

POINT

Z -230.25

Y 120.5

X100.0

Command :

G00 G90 G10 L2P2 X100 Y120.5 Z-230.25;

WORK REF

POINT


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WHY WORKPIECE

COORDINAYE SYSTEM

IT IS DIFFICULT TO WRITE PART

PROGRAMME WITH REFERANCE TO

MACHINE REF POINT ANY EDITING OR SMALL CORRECTION

NEEDS MORE CALCULATION

DIFFICULT TO READ AND UNDERSTANDPROGRAMME w.r.t. DRAWING.


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SELECTING WORKPIECE

COORDINATE SYSTEM

G54 WORK PIECE COORDINATE SYSTEM 1







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G 54 WORK


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G 54 WORK

PIECE CO

ORDINATE

SYSTEM 1

G 55 WORK


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G 55 WORK

PIECE CO

ORDINATE

SYSTEM 2


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ADVANTAGES OF MANY

WORK CORDINATE SYSTEMS WHENEVER MORE THAN ONE PART

IS BEING MACHINED ON SAME

FIXTURE, PROGRAMMING CAN BEWRITTEN MORE CONVINIENTLY FOR

EACH PART BY MENTIONING

DIFFERENT COORDIANTE SYSTEM.


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STATION3

G56

STATION1

G54

STATION2

G55


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SETTING WORKPIECE

COORDINATE SYSTEM

G00 G90 G10 L2P1 X__ Y__ Z__;

G00 G90 G10 L2P2 X__ Y__ Z__;

G00 G90 G10 L2P3 X__ Y__ `Z__;

PROGRAMMABLEDATA INPUT

WORK

COORDINATE

SYSTEM`3PAGE NUMBER


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TOOL LENGTH

OFFSET


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WHAT IS TOOL LENGTH

TOOL LENGTH

TOOL DIAMETER


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TOOL LENGTH OFFSET

ALWAYS PART PROGRAMMING IS DONECONSIDERING TOOL LENGTH ASZERO.WHEN IN ACTUL TOOL WILL BE

HAVING SOME LENGTH.

FOR SMALL VARIATION IN ONE TOOLLENGTH PART PROGRAMME HAS TO BECHANGED TO GET DESIRED QUALITY

TO COMPENASTE TOOL LENGTH w.r.t.WORK COORDINATE SYSTEMAUTOMATICALLY, TOOL LENGTH OFFSETWILL BE GIVEN


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(X0.0 Y0.0 Z0.0)WORK REF

POINT


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POINT

IF TOOL LENGTH OFFSET NOT GIVEN


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POINT

IF TOOL LENGTH OFFSET GIVEN


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TOOL DIAMETER OFFSET

ALLWAYS PART PROGRAMMING IS DONECONSIDERING SPINDLE CENTERAXIS.WHEN IN ACTUL TOOL WILL BE

HAVING SOME DIAMETER. FOR SMALL VARIATION IN ONE TOOL

DIAMETER PART PROGRAMME HAS TO BEEDITED TO GET DESIRED QUALITY

TO COMPENASTE TOOL DIAMETER w.r.t.WORK COORDINATE SYSTEMAUTOMATICALLY, TOOL DIAMETEROFFSET WILL BE GIVEN


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POINT

IF TOOL DIAMETER OFFSET NOT

GIVEN



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POINT



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G- COMMANDS FOR TOOL

LENGTH COMPENSATION

G43 - TOOL LENGTH COMPENSATION + ve

G44 - TOOL LENGTH COMPENSATION - ve

G49 - TOOL LENGTH COMPENSATION

CANCEL.


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N1 M36;

N15 G10 G90 L2P2 X-020.025 Y-134.30 Z-359.45;

N20 G10 G90 L2P3 X-204.970 Y-134.30 Z-388.24;N25 G10 G90 L2P4 X-020.025 Y-240.93 Z-420.93;

N30 T51:

N35 G0 G90 G55 X0.0 Y17.0 M03 S2000;

N40 GO G43 H1 M8;

N45 G1 G41 X-6.1 Y5.05 D1;

-----------

-----------

N75G0 G90 G56 X51.5 Y15S2500;

---------

Go G49 Z100


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G28 AND G30(Ref point return, 2nd 3rd

and 4th point return)

G28 REFERANCE POINT RETURN


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G 28

Return to reference point

Command:

G00 G91 G28 X0.0 Y0.0 Z 0.0;

G28 REFERANCE POINT RETURN

FOR REF PT RETURN IS

GENERALLY EXECUTED

ONLY IN G91 MODE

FOR REF PT RETURNGENERALLY NO

INTERMEDIATE VALUE IS

EXECUTED


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M/c REF POINT

G30 2nd 3rd & 4th REFERANCE POINT RETURN


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Command:

G00 G91 G30 P2 X0.0 Y0.0 Z 0.0;

G30 2nd 3rd & 4th REFERANCE POINT RETURN

FOR REF PT RETURN IS

GENERALLY EXECUTED

ONLY IN G91 MODE

FOR REF PT RETURN NO

GENERALLY

INTERMEDIATE VALUE IS

EXECUTED

P2 is optional for 2nd reference point, where as

P3,P4 are mandatory for respective ref point

return


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APPLICATIONS OF G30

MOVE TO TOOL CHANGE POSSITION

MOVE TO PALLET CHANGE POSITION

WHEREVER MORE THAN ONE PALLET.


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PLANE SELECTION

G17 G18 &G19

SELECTION OF PLANE IS DONE


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SELECTION OF PLANE IS DONE

FORCIRCULAR INTERPOLATION,CUTTER

COMPENSATION.G code Selected plane

G17 Xp Yp plane

G18 Zp Xp plane

G19 Yp Zp plane


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G17 Xp Yp plane

When machined is switched on G17 will be

by default


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G18 Zp Xp plane

G18 will be active till another G code of

same group is executed


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G19 Yp Zp plane

G19 will be active till another G code of

same group is executed


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Example of plane selection

T6;

G0 G90 G55 X28.75 Y-109.5 S3180 M3;

G43 H6 Z16.6 M8;

G19;

G03 Y83.7 Z16.6 J12.9 K0.0;

G0 Z16.6;

G17;


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CNC-PROGRAMMING-PART-2

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