Simple Calculation for Hole and Boss Milling

During hole and boss milling there are center distance of cutter axis and hole/boss center is very important.

This CD is defined the pitch circle diameter of cutter rotation. One condition is affect on hole milling that the cutter diameter is greater than half of hole diameter and stating point of program must be at center of hole/boss.

Formula of hole milling from the fig.

CD= (Hole Diameter - Cutter Diameter)/2

For Boss milling

CD= ( Boss Diameter + Cutter Diameter)/2

For example

The hole is 12mm of Dia. and cutter Dia. is 8mm than...

• CD = (12-8)/2
• CD = 2

Program:

N01 G01 X2 F200
N02 G03 X-2 R2
N03 X2 R2

And if Boss dia. is 15mm and cutter dia. 10mm than

• CD =(15+10)/2
• CD = 12.5

Program:

N01 G01 X-12.5 F200
N02 G02 X12.5 R12.5
N03 X-12.5 R12.5

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Circular Pattern G72.1

Often the program comes in a circular pattern. Which often seems to be repetitive. Let's learn how to copy it instead of doing it. 

When a program is rotated in a circular fixed degree, the G72.1 is used. You see how the subprogram is linked to the Maine program. In the same way, it is also linked to the subprogram and to copy it in a fixed degree.

The programming format is 

G72.1...P...L...X...Y...R...

L is a no. of program in rotation(compulsory)

R is degree between two program(compulsory)

Note : The program gets easy if your starting point of program is same with end point of program after completion of rotation copy.

G16,G17, G18, G19, G28, G51, G51.1 must not be specified in this program.

Main Program

%
O0001
N1 G0 G90 G54 X65 Y-37.53 M3 S200 (Point A)
N2 Z5
N3 G01 Z0 F300
N4 X31.681 Y-18.291 (Point B)
N5 G72.1 P0002 L6 R60 X0 Y0
N6 G90 G01 X65 Y-37.53 F300 (Point A)
N7 G0 Z100
N8 M30
%

  
Subprogram

O0002
N1 G91 G02 X5.20 Y3 R6  (Point C)
N2 G01 X3.12  (Point D)
N3 X16.02 Y10.23  (Point E)
N4 G03 Y10.11 R6  (Point F)
N5 G01 X-16.02 Y10.23  (Point G)
N6 X-3.12   (Point H)
N7 G02 X-5.20 Y3 R6   (Point I)
N8 M99
% 

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Macro Programming

macro programming is not duffer from the standard programming of CNC mill, its just used only some mathematical formulas and equations.

For macro programming learn you should have sound knowledge about the standard programming and good practical experience. The basic fundamental of macro is old G and M codes. There are nothing to new here i told only some kind of formulas are used.

In every new technologies the program get shorter and easy to use by operators. By the macro programming program gets shorten and flexible. The only one program held lot of data.

This macro condition i only used in fanuc advanced controller, i don't know others controller.

For the macro programming development there are basic three areas to understand

Variable: Stored value 

this is a main parameter of macro. Its stored the predefined value. In macro programming real data replaced by the variable

Logical Formulas: Looping

You might have heard that people of computer engineering are programming software applications or websites. Also know that If.....else is also used in it. Its called logical function.

For simple example: If I have a job I will call you. In this statement condition is i have job otherwise i will not call you. Such types of logic are used in macro for looping.

Function and constant: significant numbers

Function are used to calculate the formula and constant like basic math constant is л and its value is 3.14

The simple Program for macro is

%

O0001

N1 #100=500                ⇐ (Variable defined)

N2 #101=250                ⇐ (Variable defined)

N3 G0 G90 G54 X0 Y0

N4 Z10

N5 G01 Z0 F440

N6 Y50 F#101                                       ⇐ (Variable applied)

N7 G03 Y-50 I0 J-50 F#100                  ⇐ (Variable applied)

N8 Y50 I0 J50 F#101                            ⇐ (Variable applied)

N9 G01 Z50

N10 M30

%

Simulation of simple macro programming.

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Call Incremental Subprogram in Main Program

We saw how to call a drilling or tapping subprogram to the main program. Now how to input some complex program which is repeated by no. of time.

But what to do when we need to call a liner or a circular motion. When we need this we need to make subprogram in increment. To make a program in incremental system click here

You know very well that in incremental program system every motion origin is its previous position.

Here there are three slot in square plate, and slot dimension are same so that all liner movement will be same in incremental program.

Here we are making one sub program for only one square in incremental syatem and call it main program.

Main Program

%

O0001 (Main Program)

N1 G0 G91 G28 Z0

N2 G90 G54 X0 Y0 M03 S2000

N3 Z5

N4 G01 X25 Y25 F200

N5 M98 P0002  ⇐    (Call Subprogram)

N6 G01 G54 X60 Y60

N7 M98 P0002  ⇐    (Call Subprogram)

N8 G01 G54 X100 Y100

N9 M98 P0002  ⇐    (Call Subprogram)

N10 Z10 

N11 G0 G91 G28 Z0

N12 M05

N13 M30

%

Subprogram

%

O0002 (Sub Program)

N1 G91 G01 Z-5 F50

N2 X25

N3 Y25

N4 X-25

N5 Y-25

N6 Z5

N7 M99

%

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