CNC PROGRAMMING FOR BEGAINER Part 1

CNC Machines

• What is a CNC Machine?

• CNC : Computerised Numerical Control
• Conventionally, an operator decides and adjusts
various machines parameters like feed , depth of cut
etc depending on type of job , and controls the slide
movements by hand. In a CNC Machine functions
and slide movements are controlled by motors using
computer programs.

Definition of Numerical Control M/C
E.I.A : -(Electronic Ind. Association) defines NC Control as
‘’A system in which actions are controlled by direct
insertion of numerical data or at least some portion of this
data.” In simpler language NC means control by number.
The input information's for controlling the machine tool
motions is provided through punched paper tape or
Magnetic tapes in a coded language.
E.I.A -Electronic Ind. Association.
ISO -International standard Organization.
ASCII -American standard code for Information
Interchange.

CNC :-Computerised Numerical Control
Computerised Numerical Control is a numerical
control system that utilizes a dedicated stored
programmed. Computer is used to perform some or all
basic function. Numerical control is a programmable
automation in which process is controlled by Numbers,
Letters, and symbols. (Computer +NC= CNC).
Some of the typical function of CNC M/C are:•Machine Tool Control.
•In Process Compensation.
•Graphics.
•Diagnostics.
•Number of CNC M/C Axis : 2,3,4,-------------------24axis.

DNC :- Direct Numerical Control.
Direct Numerical Control is a manufacturing
system in which number of M/C are
controlled by a computer through direct
connection and in real time. One computer
can be used to control 100 separate
machines and it is designed to provide
instructions to each M/C tool on demand.

Benefits of DNC
1. NC. Without punched tapes.
2. Greater computation & Flexibility.
3. Convenient storage of NC Part Programme in computer
file. (General format of Programme as C.L. file.)
4. Data collection function like shop floor Control
etc.(Processing & Reporting of shop performance.)
5. Direct conversion of data from CAD to NC Programme.
6. Increases Productivity.
7. Save time.
8. Post Processing.

CNC Machines- Advantages/Disadvantages
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•
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•
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Advantages:
High Repeatability and Precision e.g. Aircraft parts
Volume of production is very high
Complex contours/surfaces need to be machined. E.g.
Turbines
Flexibility in job change, automatic tool settings, less scrap
More safe, higher productivity, better quality
Less paper work, faster prototype production, reduction in
lead times
Disadvantages:
Costly setup, skilled operators
Computers, programming knowledge required
Maintenance is difficult

Conditions Suitable for Introducing CNC M/C.
•Labour cost of the component--------------- High.
•Size of batches ----------------------------------- Small.
•Repetation of batches-------------------------- Often.
•Complexity of the operation Carried out-- High.
•Number of operation per Component------ Many.
•Time lag between operation ------------------ Low.
•Ratio of cutting time to non cutting time ---Low.
•Variety of Components to be produced ---- More.
•Design changes------------------------------------ Frequent.
•Non uniform cutting conditions -------------- Required.
•Cost of special tooling involved--------------- High.
•Skill required by the operator ---------------- High.
•Set-up time /Inspection time----------------- Low.
•Number of dimensions to be maintained-- Many
•Precision involved in the components------ High.

MACHINE TYPES
1. Group 1: -M/C Tools with rotating tool i.e. Milling
M/C, Drilling M/C, Boring M/C , Tapping M/C
2. Group 2: -M/C Tool with Rotating work piece i.e.
Lathe.

3. Group 3: -Non Rotating work Piece and non
rotating tool i.e. Shaper, Planer, EDM, Wire cut.
4. Group: -Other than above Z Categories i.e. NC
Drafting.

Classification of Controllers
1. Point to Point type (P-Type)
A. )Only Positioning.
B.) No Control over Feed speed.
C.) Semi Automatic Drilling M/C Spot Welding M/C etc.
2. Position Control (2PL)
3. 2L/3L Controllers.
4. Continuous Control (C-Type Controllers)
A.) 2CLa.) 2 ½ Axis Controllers.
b.) Simultaneous Control of two Axis + Feed control of one Axis.
c.) Can make 2-D Fig. Like Circle, Arc Ellipse.
B.) 3C
a.) 3 Axis Simultaneous
b.) Can do interpolation in 3 Dimensions
C.) Can Produce Sphere
D.) Most Suitable for Production Operations

Motion and coordinate system for NC machine
Z-axis: Always aligned with the spindle that imparts cutting power.
This spindle might rotate the work-piece as in a lathe, it might rotate a tool
as in a milling machine. It is perpendicular to work-holding surface if there
is no such spindle. Positive motion in z axis tends to increase the
separation between the work-piece and the tool

X axis: Positioning the moving element, parallel to the work-holding
surface, horizontal (if possible). On machines with rotating work-pieces, it
is radial and parallel to the cross-slide On machines with rotating tools,
1.If the Z-axis is horizontal, the positive x motion is to the right when
looking from the spindle to the work-piece.
2. If the z axis in vertical, the positive x axis is to the right when looking
from the spindle to the column On machines with non-rotating workpieces and non-rotating tools, the x axis is parallel to and directed toward
the principal cutting direction
Y-axis: be in such a direction as to complete a right-handed
Cartesian coordinate system

What , if you have Multi spindle M/C
Select principle spindle as Primary „Z‟ axis and
other slides/quills are termed as secondary tertiary
motion axis.
Axis

Rotator Axis
A,B,C

Principal:
Second:
Tertiary:

X,Y,Z
U,V,W
P,Q,R

Fanuc used: - ‟U,V,W‟ to designates
Incremental Movement in „X,Y,Z direction. „X,Y,Z is
used to designates Absolutes Motion.

Axes convention
The tool can be moved to any position in a 3 dimensional cartesian co-ordinate
system.
The Z axis is along the spindle axis. The X and Y axes are perpendicular to Z.
VMC (Vertical Machining Center)

HMC (Horizontal Machining Center)

Open Loop Control System
A Control system in which the final output value is not directly measured
and checked against the desired value is know as open loop control system.
In open loop control system, there is no feedback device to measure the
actual position of tool slide or work table. Hence it can not be compared &
verified with Positional value given in command.
Closed Loop Control System
A control system in which the displacement of machine slide is balanced
signal received from feed back devices is known as closed loop control system.
There are two input signals to drive a motor. One is command signal due to which
the servo motor is driven. As soon as the displacement takes another signal is
generated by the position sensor known as transducer to know that whether the
position has-been achieved or not. This actual position signal is feed to the
comparator device, which compares it with command signal and produces an
electrical signal proportional to the difference between the two. This signal is feed
to the servo motor through an amplifier to move the machine slide in a direction
to reduce the difference. This loop is followed again and again till the difference
between the two signals (input and feedback) becomes of zero amplitude.

Open-loop Control
• Stepper motor is used, having a predefined amount of revolution.
• Current pulses are send from MCU to individual motors.
• Movement/rotation depends on number of pulses send.

Advantages:
• Position is maintained just by keeping track of number of revolutions.
• Can produce a movement of 1/1000th of an inch, for a single pulse.
• Cheap and less complex.
• Easy to maintain.
Drawback:
• Assumption: Motor movement is precise, i.e. motor is moving the exact
amount depending on the number of pulses.
• No way to correct errors, because no feedback.
• This control is not suitable for large machines requiring greater power
because of limitation of stepper motor to generate high torque.

•Closed-loop Control
• Direct current (DC) motors are used.
• Can generate high levels of torque.
• Can be reversed.
• Unlike stepper motors, it cannot achieve very precise
movement.
• Separate positions sensors are required.
• Position information is fed back as a signal to the controller.
•Major advantage: because of feed back and servo motors
Types of NC control systems reversible feature, errors can be
corrected, by comparing with target position.
• Thus formed a closed loop.
• Higher accuracy than open loop systems because of feed
back.
• Applications:
•Larger NC machines because of higher loads.
•For greater accuracy, any kind of load.
• Expensive and complex.

What the Programmer has to do to make Part
Programming
1. Study the relevant component drawing thoroughly.
2. Identify the type of material to be machined.
3. Determine the specifications & function of M/C to be used.
4. Decide the dimension and mode: -metric or inch.
5. Decide the coordinate system: -Absolute or Incremental.
6. Identify the plane of cutting.
7. Determine the cutting parameters for the job/tool combination.
8. Decide the feed rate programming: -MM/MIN or M/Rev.
9. Check the tooling required.
10.Establish the sequence of machining operations.
11.Identify whether use of special features like Subroutines, Mirror, Imaging
etc. is required or not.
12.Decide the mode of storing the part program once it is completed.

CRT Key Board
Operator Paned
Console Interface
Taper Redder
Punch Tape

Central
Processing Unit
CPU

X Axis

Servo Amplifier

Servo Motor

Encoder

Y Axis

Servo Amplifier

Servo Motor

Encoder

Z Axis

Servo Amplifier

Servo Motor

Encoder

Detail Drawing

Producing Planning

Component Size

Type of Machining Required

Form in which stock material is supplied

Machining type (Machine Setting)

Process Operation schedule and time estimation

Work holding and location

Speeds and feeds

CNC Machining program

Program Proving

Component production

Tooling type

Coordinates System
Incremental Coordinate System

Absolute Coordinate System

Absolute and Incremental co-ordinates
In the absolute programming, the end point of a motion is
programmed with reference to the program zero point.
In incremental programming, the end point is specified with
reference to the current tool position.
Absolute traverse to N1, then to N2
X20.0 Z50.0
X50.0 Z30.0
Absolute traverse to N1, incremental to N2
X20.0 Z50.0
U30.0 W-20.0

A X2.000 Y2.000
B X1.000 Y-2.000

G90 ABSOLUTE POSITION COMMAND
When using a G90 absolute position command, each
dimension or move is referenced from a fixed point, known as
ABSOLUTE ZERO (part zero). Absolute zero is usually set at
the corner edge of a part, or at the center of a square or
round part, or an existing bore.
ABSOLUTE ZERO is where the dimensions of a part
program are defined from. Absolute dimensions are
referenced from a known point on the part, and can be any
point the operator chooses, such as the upper-left
corner, center of a round part, or an existing bore.
G91 INCREMENTAL POSITION COMMAND
This code is modal and changes the way axis motion
commands are interpreted. G91 makes all subsequent
commands incremental.

What is the value in X and Y for each hole in absolute G90 positioning when each move
is defined from a single fixed part zero point of an X0 Y0 origin point.
PT1 = X______ Y______
PT2 = X______ Y______
PT3 = X______ Y______
PT4 = X______ Y______
From PT8 to PT9 = X______
PT5 = X______ Y______
PT6 = X______ Y______
PT7 = X______ Y______
PT8 = X______ Y______

Y______
Y______
Y______
Y______
From PT12 to PT13 = X______ Y______
From PT13 to PT14 = X______ Y______
What is the value for each hole in INCREMENTAL G91 positioning when each move
is defined from the previous position and the zero point shifts with the new position.

Fixed zero V/S Floting zero
Fixed zero: -Origin is always located at some
position on M/C table (usually at south west
corner/Lower left-hand) of the tables & all tool
location are defined W.R.T. this zero
Floting Zero: •Very common with CNC M/C used now a days.
•Operator gas lobeity to set zero point at any
convenient position on M/C table
•The Coordinate system is knows as work coordinate
system (WCS)

Part Programme
The coded instructions or commands listed in a logical sequence to have a
machine tool perform a specific tasks or a series of tasks in order to produce a finished
product in the minimum amount of time.
Programming Format
%
N
G
X,Y,Z
U,V,W
P,Q,R
I,J,K
A,B,C
R
F
S
T/D
M
EOB

Programme Number.
Sequence Number (Block Identification Number).
Preparatory functions (G00 to G99). This prepares the M/C for next operation.
Primary motion Dimension in the X,Y,Z direction respectively.
Secondary motion Dimension in the X,Y,Z direction respectively.
Tertiary motion Dimension in the X,Y,Z direction respectively.
Distance to the are center or thread leads parallel to X,Y,Z respectively.
Angular Dimension around in the X,Y,Z direction respectively.
Parameters.
Feedrate.
Spindle Speed/Cutting Speed.
Tool number.
Miscellaneous function (Machine Codes)
End of Block.

PART PROGRAMMING FOR CNC
The transfer of an engineering blueprint of a product to a part
program can be performed manually using a calculator or with the
assistance of a computer language. A part programmer must have an
extensive knowledge of the machining processes and the capabilities of
the machine tools . In this section, we describe how the part programmers
execute manually the part programs.
First, the machining parameters are determined . Second, the
optimal sequence of operations is evaluated . Third, the tool path is
calculated . Fourth, a program is written. Each line of the program, referred
to as a block, contains the required data for transfer from one point to the
next.
A typical line for a program is given below.
N100 G91 X -5.0 Y7 .0 F100 S200 T01 M03 (EOB)

DEFINITIONS WITHIN THE FORMAT
1. CHARACTER : A single alphanumeric character value or the "+" and "-" sign.
2. WORD : A series of characters defining a single function such as a, "X"
displacement, an "F" feedrate, or G and M codes. A letter is the first character of a
word for each of the different commands. There may be a distance and direction
defined for a word in a program. The distance and direction in a word is made up
of a value, with a plus (+) or minus (-) sign. A plus (+) value is recognized if no sign
is given in a word.
3. BLOCK : Series of words defining a single instruction. An instruction may consist
of a single linear motion, a circular motion or canned cycle, plus additional
information such as a feedrate or miscellaneous command (M-codes).
4. POSITIVE SIGNS : If the value following an address letter command such as
A, B, C, I, J, K, R, U, V, W, X, Y, Z, is positive, the plus sign need not be
programmed in. If it has a minus value it must be programmed in with a minus (-)
sign.
5. LEADING ZERO'S : If the digits proceeding a number are zero, they need not
be programmed in. The control will automatically enter in the leading zero's.
EXAMPLE: G0 for G00 and M1 for M01, Trailing zeros must be programmed: M30
not M3, G70 not G7.

6. MODAL COMMANDS : Codes that are active for more than the line in which they
are issued are called MODAL commands. Rapid traverse, feedrate moves, and
canned cycles are all examples of modal commands. A NON-MODAL command which
once called, are effective only in the calling block, and are then immediately forgotten
by the control.
7. PREPARATORY FUNCTIONS : "G" codes use the information contained on the line
to make the machine tool do specific operations, such as :
1.) Move the tool at rapid traverse.
2.) Move the tool at a feedrate along a straight line.
3.) Move the tool along an arc at a feedrate in a clockwise direction.
4.) Move the tool along an arc at a feedrate in a counterclockwise direction.
5.) Move the tool through a series of repetitive operations controlled by "fixed cycles"
such as, spot drilling, drilling, boring, and tapping.
8. MISCELLANEOUS FUNCTIONS : "M" codes are effective or cause an action to
occur at the end of the block, and only one M code is allowed in each block of a
program.
9. SEQUENCE NUMBERS : N1 thru N99999 in a program are only used to locate and
identify a line or block and its relative position within a CNC program. A program can
be with or without SEQUENCE NUMBERS. The only function of SEQUENCE
NUMBERS is to locate a certain block or line within a CNC program.

Programming Key Letters
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•
•
•
•
•
•
•
•
•
•
•
•

O - Program number (Used for program identification)
N - Sequence number (Used for line identification)
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

List of G-codes
G-code Function
G00
Positioning rapid traverse
G01
Linear interpolation (feed)
G02
Circular interpolation CW
G03
Circular interpolation CCW
G04
Dwell
G20
Inch unit
G21
Metric unit
G28
Automatic zero return
G40
Tool nose radius compensation cancel
G41
Tool nose radius compensation left
G42
Tool nose radius compensation right
G43
Tool length compensation
G54
Work co-ordinate system 1 selection
G55
G56
G57
G58
G59

G80
G81
G82
G83
G84
G85
G86
G87
G90
G91
G94
G95
G98
G99

Canned cycle cancel
Drilling cycle
Drilling cycle with dwell
Peck drilling cycle / deep drill
Tapping cycle
Boring / Reaming cycle
Boring cycle
Back boring cycle
Absolute command
Incremental command
Feed per minute
Feed per revolution
Return to initial point in canned cycle
Return to R point in canned cycle

List of M codes
M codes vary from machine to machine depending on the functions available on it.
They are decided by the manufacturer of the machine. The M codes listed below are
the common ones.

M-codes
M00
M01
M02
M03
M04
M05
M06
M07
M08
M09
M30
M98
M99

Function
Optional program stop automatic
Optional program stop request
Program end
Spindle ON clock wise (CW)
Spindle ON counter clock wise (CCW)
Spindle stop
Tool change
Mist coolant ON (coolant 1 ON)
Flood coolant ON (coolant 2 ON)
Coolant OFF
End of program, Reset to start
Sub program call
Sub program end

History of CNC
The word address format

Each line of program == 1 block
Each block is composed of several instructions, or (words)
Sequence and format of words:
N3 G2

sequence no

X+1.4 Y+1.4 Z+1.4

I1.4 J1.4 K1.4

destination coordinates

dist to center of circle

preparatory function

F3.2

S4

T4 M2

tool

feed rate spindle speed
miscellaneous function

ABSOLUTE PRESET G92
USED TO SHOW CURRENT TOOL POSTION W.R.T. ZERO AT
THE TIME OF STARTING M/C.
ONCE THE CUTTER POSITION IS DEFINED USING G92 M/C
WILL DRAW ITS CO-ORDINET SYSTEM
ONCE G92 IS DEFINED THEN THERE IS NO NEED TO DEFINE
G90
IT IS MODEL
FORMAT
G92 X__ Y__ Z__
ZERO OF JOB)

(CURRENT TOOL POSITION W.R.T

REFERENCE POINT AND RETURN
G28 Return To Reference Point, set optional intermediate point
The G28 code is used to return to the machine zero position on all
axes. If an X, Y, Z, or A axis is on the same block and specifies a
location, only those axes will move and return to the machines‟ zero
reference point and the movement to the machines„ zero reference
point will be through that specified location.
Format: -G91 G28 X0 Y0 Z0;

Setting work co-ordinate system (G54 - G59)
G54 Work co-ordinate system 1 selection
G54 X_ Y_ Z_；

G00 Rapid traverse
When the tool being positioned at a point preparatory to a cutting motion, to
save time it is moved along a straight line at Rapid traverse, at a fixed traverse
rate which is pre-programmed into the machine's control system. Typical rapid
traverse rates are 10 to 25 m /min., but can be as high as 80 m/min.
Format
N_ G00 X__ Y__Z__

G01 Linear interpolation (feed traverse)
The tool moves along a straight line in one or two axis simultaneously at a programmed
linear speed, the feed rate.
Format
N__ G01 X__ Y__Z__ F__

Format
N__ G02/03 X__ Y__Z__ I__ J__K__ F__ using the arc center
OR
N__ G02/03 X__ Y__Z__ R__ F__ using the arc radius
G02 moves along a CW arc
G03 moves along a CCW arc
Arc center
The arc center is specified by addresses I, J and K. I, J and K are the X, Y and Z
co-ordinates of the arc center with reference to the arc start point.

I = X coord. of center - X coord. of start point
J = Y coord. of center - Y coord. of start point
K = Z coord. of center - Z coord. of start point
I, J and K must be written with their signs.

Arc radius
The radius is specified with address R.

Block format
N__ G02 X__Y__ Z__ R__ F__
N__ G03 X__Y__ Z__ R__ F__

DWELL COMMAND
G04 Dwell
Format：G04X_; or G04F_; or G04P_;
X: Specified time(decimal point is permitted)
F: Specified time(decimal point is permitted)
P: Specified time(decimal point is unpermitted)
Explanation：G04 command dwell. The execution of the next
block is delayed by the specified time, specify dwell for each
rotation in feed per rotation mode. Dwell is use to stop feed
for specified period of time.
G04 X15 ,G04 F15, G04 P15000
Here M/C will Dwell for 15 second. The function Not modal. It
can be used in Boring, Making CAM Profile, at these point
dwell is required.

G15/G16 Commands of polar coordinate
The value can be inputted in the form of the polar
coordinates (radius and angle )
The angle is position when the first axis of the
selected plane is anticlockwise, and negative when
it is clockwise.
G16；Start the command of polar coordinates
(polar coordinates mode)
G15 ；Cancel the order of polar coordinate.

G17/G18/G19 Selection of planes
Use the parameters to appoint the circumrotate axis is X
Y or Z ,or the axis that parallel to these axis , specify the
G code to select the plane , to this plane , the
circumrotate axis is the appointed line axis. For
example, when the circumrotate axis is the axis that
parallel to the X axis ,G17 should specify the plane of X
and –Y, and only circumrotate axis one can be set.
When we omit the address of the axis of X Y and Z , we
consider the third axis’s address is omitted
In the program, which are not appointed by the order of
G17 G18 G19,the plane stay the same.

Inch/metric command change; G20, G21
G20/G21;

G20 : Inch command
G21 : Metric command
G20 and G21 selection is meaningful only for linear axes and
it is meaningless for rotary axes.
The input unit for G20 and G21 will not change just by
changing the command unit.
In other words, if the machining program command unit
changes to an inch unit at G20 when the initial inch is
OFF, the setting unit of the tool offset amount will remain
metric. Thus, take note to the
setting value.

Cutter radius compensation (CRC)

G40 Tool nose radius compensation Cancel
G41 Tool nose radius compensation Left
G42 Tool nose radius compensation Right
Format: G41 X_ Y_D_；
G42 X_ Y_D_；

SUBROUTINE
A subprogram is a separate program called up by another
program. The use of subprograms can significantly reduce the
amount of programming on some parts. Subroutines allow the
CNC programmer to define a series of commands which might
be repeated several times in a program and, instead of
repeating them many times, they can be “called up” when
needed. A subroutine call is done with M98 and a Pnnnn. The P
code command identifies the O program number being used
when executed with M98
M99: -An M99 ends a sub-program and returns back to the next
line in the main program after the M98 sub-program call.

Tool length compensation (G43)
Different tools of different lengths are used in machining any part. The lengths of the tools are
not considered in the part program. They are entered in the machine’s memory, and are
considered automatically for each motion in the program depending on the tool that is being
used. The tool lengths in the Z direction are called the Tool length offsets.
Codes Function
G43
Make the value of the cutter’s offset add to the value of Z coordinates of the program
G44
Make the value of the cutter’s offset subtract the value of Z coordinates of the Program
G49
Cancel the offset of the length of the cutter
Format: G43 Z_ H_；
G44 Z_ H_；
G49 Z_；

Canned cycles
Canned or fixed cycles are programming aids that simplify programming. Canned
cycles combine many programming operations and are designed to shorten the
program length, minimize mathematical calculations, and use minimal tool motions.
Examples : drilling, peck drilling, tapping, boring, back spot facing.
G81 Drilling cycle
G82 Drilling cycle with dwell (Counter bore cycle)
G83 Peck drilling cycle / deep drill
G84 Right hand tapping cycle
G85 Boring / Reaming cycle
G86 Boring cycle
G87 Back boring cycle
G74 Left hand tapping cycle
G76 Fine boring cycle
G98/G99 plane of return point
When the tool gets to the bottom of the hole, it can return back to the plane of R
point and the initialized plane initialized by G98/G99. Generally speaking, G99 is
used in the first drilling plane while G98 is used in the last drilling, even though we
use G99 to drill, the plane of the initialized position would keep the same.

G81 X_Y_Z_R_F_K_；
X_ Y_: Data of hole site
Z_: Depth of the bottom of hole(absolute coordinate）
R_: Starting point or raising point per time（absolute coordinate）
F_: Feeding rate of cutting
K_: Number of replication (if necessary)

G82 X_Y_Z_R_P_F_K_；
R_: Starting point or raising point per time (absolute coordinate）
P_: Pause time (unit：ms)

G83 X_Y_Z_R_Q_F_K_；
R_: Starting point or raising point per time (absolute coordinate）
Q_: Offset of hole bottom

G84 X_Y_Z_R_P_F_K_；operation manual FANUC milling programming

G85 X_Y_Z_R_F_K_；
X_ Y_: Depth of the bottom of hole(absolute coordinate）

G86 X_Y_Z_R_F_K_；

G87 X_Y_Z_R_Q_P_F_K_；
X_ Y: Data of hole site

G88
Fixed point dring cycle (G88)
Format G88 X_Y_Z_R_P_F_K_;

G88 Pause when feeding to bottom and
spindle stops then withdraw quickly

G89
Boring cycle(G89)
Format G89 X_Y_Z_R_P_F_K_；

G89 Pause when feeding to bottom and
spindle stops then withdraw quickly
Example
N005 G80 G90 G0 X0 Y0 M06 T1 ；change the boring cutter of Ø20
N010 G55 ；call workpiece coordinate of G55
N020 M03 S1000
N030 G43 H1 Z50 ；call length compensation
N040 G89 Z-30 R1 P2000 F200 ；boring cycle
N050 G80 G0 Z50 ；cancel fixed circle
N060 M05
N070 M30

G73
Rapid depth drill circle(G73)
Format G73 X__Y__Z__R__Q__ F__K__
Q_: Depth of cutting per time（no symbol, increment）

G74 X__Y__Z__R__ P__F__K__
P_: Depth of cutting per time（no symbol, increment）

Fine boring cycle (G76)

G76 X__Y__Z__R__Q__P__F__K__

CIRCULAR POCKET MILLING
There are two G codes, G12 and G13 that will provide for pocket milling of a circular
shape. They're different only in which direction of rotation is used. G12 and G13 are
non-modal.
G12 Circular Pocket Milling Clockwise
X
Position in X axis to center of circular pocket
Y
Position in Y axis to center of circular pocket
Z
Z depth of cut, or it's the increment depth of cuts when used with G91
I
Radius Of First Circle (Or it's the finish radius if K is not used)
K
Radius Of Finished Circle (If specified)
Q
Radius cut increment step-over of the spiral out (Q is used with K only)
L
Loop count for repeating incremental depth of cuts (L is used with G91)
D*
Cutter Comp. Offset Number (Enter cutter size in offset display register)
F
Feed Rate in inches (mm) per minute
This G12 code implies the use of G42 cutter compensation right
G13 Circular Pocket Milling Counterclockwise

This G13 code implies the use of G41 cutter compensation left and will be
machining in a counterclockwise direction, but is otherwise the same as G12.
G13 is usually preffered instead of G12, since G13 will be climb cutting when used
with a standard right handed tool.

CNC PROGRAMMING FOR BEGAINER Part 1

CNC PROGRAMMING FOR BEGAINER Part 1

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CNC PROGRAMMING FOR BEGAINER Part 1