cad/cam lab cnc programming - vidyarthiplus

CAD/CAM LAB

CNC PROGRAMMING

www.Vidyarthiplus.com


CAD/CAM

• Computer-Aided Design (CAD)

– Use of computer systems to create a design of a complexpart .

• Computer-Aided Manufacturing (CAM)

– Use of computer systems to do the manufacturing operationsthrough Numerical control code( part programming).



Numerical control

• Numerical control is a automatic operating method of machine

based on a numerical code of letters, numbers, and special

characters.

• The numerical code required to produce a part is given to

machine in the form of a program, called part program or

CNC program.

– The process of creating a set of instructions or commands to perform

machining operations in CNC machine.• G00 X21 Z1; //Rapid positioning to x21 z1

• G94 X-0.5 Z-0.5 F50; // Facing cycle

• The given program is translated into the appropriate electrical

signals for input to motors that run the machine.www.Vidyarthiplus.com


Terminology

• Programming character

– is an alphanumeric character or punctuation mark: N G ;

• Address

– is a letter that describes the meaning of the numerical value that follows

the address: G00, G90, S1500

• Words

– are built by characters and are composed of two main parts: an address

followed by a number in order to describe machine motions and

dimensions in a program: G00 x21 z1

• Block

– is a complete line of information to the CNC machine. Comprise of a

word or an arrangement of words



Part programming- Common Format

Sequence #

Preparatory Function

Dimension Words

Feed Rate

Spindle Function

Tool Function

Misc. Function

N50 G90 G01 X1.40 Z2.25 F10 S1500 T01 M03

Block for machiningwww.Vidyarthiplus.com


BASIC MOVEMENTS (XL TURN):

X+(U, I)

Z+(W, K)

Z-

X-



Absolute programming:

The programmer commands the tool tip point

to move to a new position which is at specific

distance and direction from a particular

reference point (which may be acting as an

origin)

10

20

30



Incremental programming:

The programmer commands the tool tip point

to move to a new position which is at specific

distance and direction from its previous

position101010



PREPARTORY FUNCTIONS (G CODES) FOR XLTURN:

G-codes are sometimes called cycle codes.

• They do action or movement on the X, Y, and/or Z axis of a machine tool.

G00 : Positioning in rapid.

G01 : Linear positioning in feed.

G02 : Circular interpolation CW.

G03 : Circular interpolation CCW.

G20 : Input in Inch.

G21 : Input in Metric.

G28 : Return to Reference position.

G90 : Absolute command.

G91 : Incremental command.

G94 : Feed per revolution.www.Vidyarthiplus.com


Miscellaneous Functions (G CODES) FOR XLTURN:

M or miscellaneous codes are used to either turn ON or OFF different functions which control certain machine tool operations.

M00 - Program stop

M02 - End of programM03 - Spindle start (forward CW)M04 - Spindle start (reverse CCW)M05 - Spindle stopM06 - Tool changeM08 - Coolant onM09 - Coolant offM30 - End of tape and rewind



Facing Operation



SINGLE FACING CYCLE.

[BILLET X20 Z70; //Size of the work piece

G21 G98; // inputs in metric, rapid transverse to ideal position

G28 U0 W0; // Return to ref. position

M06 T01; // Tool change

M03 S1500; //Spindle start(forward clockwise)

G00 X21 Z1; //Rapid positioning to x21 z1

G94 X-0.5 Z-0.5 F50; // Facing cycle

Z-1;Z-1.5;Z-2;G28 U0 W0; // Return to ref. position

M05; // Spindle stop

M30; // End of machiningwww.Vidyarthiplus.com


SINGLE TURNING CYCLE.

[BILLET X25 Z70;G21 G98;G28 U0 W0;M06 T01;M03 S1500;G00 X26 Z1;G90 X25 Z-20 F40;G01 X23;G01 X21;G01 X19;G01 X17;G01 X15;G01 X13;G01 X11;G01 X10;G28 U0 W0;M05;M30; www.Vidyarthiplus.com


MULTIPLE FACING CYCLE



MULTIPLE FACING CYCLE[BILLET X25 Z70; //Size of the work piece

G21 G98; // inputs in metric, rapid transverse

G28 U0 W0; // Go to ref. position

M06 T01; // Tool change command



G72 W0.5 R0.5; W – Depth of cut.

R-Return value after a cut is complete.

G72 P10 Q20 U0.1 W0.1 F70;

P – Contour start block number.

Q – Contour end block number.

U- Finishing allowance in x-axis

W- Finishing allowance in z-axis

G28 U0 W0;

M05;

M30;

G01 X25 Z-29;X20 Z-24;X20 Z-16;X17 Z-13 R3;X12 Z-10 R3;X12 Z-05;X10 Z0;

N10G01G01G03G02G01G01N20



MULTIPLE TURNING CYCLE



MULTIPLE TURNING CYCLE[BILLET X22 Z70; //Size of the work piece






G71 W0.5 R0.5; W – Depth of cut.

R-Return value after a cut is complete.

G71 P10 Q20 U0.1 W0.1 F70;

P – Contour start block number.

Q – Contour end block number.

U- Finishing allowance in x-axis

W- Finishing allowance in z-axis

G28 U0 W0;

M05;

M30;

G01 X0 Z0;X10 Z-5 R5 ;X10 Z-15;X15 Z-20;X15 Z-28;X22 Z-28;

N10G03G01G01G01G01N20



Multiple threading Cycle



MULTIPLE THREAD CYCLE[BILLET X50 Z50; //Size of the work piece






G90 X50 Z-25 F40;G01 X45;G01 X40;G01 X35;G01 X30;G01 X25;G01 X20;

G28 U0 W0;M06T05;M03 S1500;G76 P031560 Q50 R0.015 03 –Number of passes,15-Chamber angle,

60-Angle of threadQ-minimum cutting depth(50 microns=0.05mm)R- Finishing allowance=0.015mm

G76 X20 Z-19 P1073 Q50 F1.5X-Core diameter=20mm, Z=length of threadP-height of thread=1073microns(1.073mm)Q-Depth of cut for the first pass= 50 micronsF-pitch of the thread

G28 U0 W0;

M05;

M30;



cad/cam lab cnc programming - vidyarthiplus

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