Link to us from your website and promote the community!... Then email us to receive a Free CNC cheat sheet from the CNC Specialty Store!

Facebook Group

Share your CNC information?
...Procedures
...Macro programs
...Articles
...and more

Suggestions or comments?
Please Email Us

Thank you for all your contributions and supporting the CNC community.

Multi cut threading macro program example using G76

Custom Macro – Using variables for the Programming :

Ideal application for the use of Variable programming (i.e. Custom Macro Programming) on a CNC Lathe :

As such the usage is covering very vast application area. You name it and it can be coded using macros. But, by and large following are the core application areas :  

1)   Threading applications like variable lead threading, Multi start threading,   

      Square and Trapezoidal threading, circular form non-standard type    

      threading ;  

2)   Multi-start worm cutting ; 

3)   Face and radial grooving of non-standard type;  

4)   Design one’ s own cycle of any type.

Example :  Carrying out 4 start threading of the size – M16 x 2.0 mm pitch.  Write a custom Macro “A” Program for the same. Use Multi-cut threading cycle – G76. Use following data :

Data : 

i)     O. D. = 15.8 mm  
ii)    δ1 = 30.0 mm  
iii)   δ2 = 5.0 mm  
iv)   1st cut depth = 0.3 mm  
v)    Lead = Pitch x no. of starts = 2 x 4 = 8 mm  
vi)   Chamfer amount = 1.0 times the lead.  
vi)   Root diameter = 13.3 mm  
vii)  Thd. Height = 1.25 mm  
viii) Length of threads = 50 mm  
ix)   No. of finishing passes = 3 nos.  
x)    Limiting depth of cut per pass = 0.075 mm  
xi)   Depth of cut for finishing pass = 0.050 mm.
xii)  Angle of Approach = 60 degrees.

(A)   Custom Macro – A for FANUC OT-D/C systems

O0001 (4 START THREADING);

N1;
T0000;
G28 U0 W0;
T0101;
G50 S800;
G97 S800 M03;
G65 H01 P#100 Q30000;
M08;
N10;
G0 X17.0 Z#100;
G65 H83 P20 Q#100 R36000;
G76 P031060 Q75 R50;
G76 X13.3 Z-55.0 P1250 Q300 F8.0;
G65 H02 P#100 Q#100 R2000;
G65 H80 P10;
N20;
M09;
G97 M05;
G28 U0 W0;
M30;
%

(B)  Custom Macro “B” for FANUC Oi Mate – TB/TC system :

O0001 (4 START THREADING);

N1;
T0000;
G28 U0 W0;
T0101;
G50 S800;
G97 S800 M03;
#100 = 30.0;
M08;
N10;
G0 X17.0 Z#100;
IF [#100 GT 36.0] GOTO 20;
G76 P031060 Q75 R50;
G76 X13.3 Z-55.0 P1250 Q300 F8.0;
#100 = #100 + 2.0;
GOTO 10;
N20;
M09;
G97 M05;
G28 U0 W0;
M30;
%

____________  

Jasmin C. Shah,

CNC Application Engineering and Programming consultant

Date :  13th September, 2006