Hi everybody. i am new to CNC programming and learning turning program. i went through canned cycle G77 / G78 but could not write program. there is no example in the mach3 manual. I need help how to initiate G77 and G78 for rough cut and finish cut to cut 20mm out of 25mm dia billet. thanks in advance

Instructor,
G77 & G78 canned cycles do not exist for Mach but may be applicable for a Fanuc or Siemens controller.
There are wizards, macros, LazyCam, and Lazyturn code output that you can have a look at for manual coding.

RICH

MODIFIED:  PLEASE READ MY ADDITIONAL REPLIES THAT FOLLOW ON G77/G78 

Here is a link on  the use of a G77 / G78  in Mach.
 
http://www.machsupport.com/forum/index.php/topic,4297.msg30870.html#msg30870

Note also in the above link there is another Macro M1077 posted by Andy.
Read Andy's comment on putting the settings in Config> Ports & Pins>Turn Options of Mach3 Turn.

I remember trying out the M1077 and the M1078 a long time ago. They can be found Macro folder for the lathe.
Open them up with the V Script Editor to confirm which one is which ( M1077 is G77 and M1078 is G78 if i recall).


NOTE that some of the settings in Turn Options are relative to threading, thus be carefull, and see The Threading on The Lathe Manual
page 44 for an explaination.

RICH

While I'm at it.....
There is another macro in the lathe Macro's folder, namely, M1083 for lathe drilling. I don't use it and prefer the lathe
peck drilling macro in the following link.

http://www.machsupport.com/forum/index.php/topic,15205.msg101682.html#msg101682

RICH

Thanks Mr.RICH for your quick response and suggestions. But I am new to this macro editing using vb script. Anyway i'll try to go through your suggestion. Meanwhile please let me know whether there is any alternative codes to use canned cycle for turning.
 For Ex. I want to turn out 20mm through 30mm out of 25mm dia and 50mm length billet. please explain me how to write repetitive program for this. Thanks once again for your answer

I am new to this macro editing using vb script

The macro's don't need editing. Operations tab>v script editor> then open the file to have a look at the file contents.

alternative codes to use

The bulk of Gcodes available for Mach Turn are listed in the manual, but the manual was written a long time ago, so there are
 some canned cycles / macros done by users and the ones i posted are a good example. You may find some lathe canned Gcodes
 for  other controllers but they were specific for say a Fanuc controller and are not supported by Mach.

The Mach Turn Wizards provide for manny of the common single tasks to be done on the lathe. Lazyturn and LazyCam can give you code for turning a profile.

how to write repetitive program

Hm......not sure what you mean by repetitive
Do you just want to use the program generated g code for a single task, have the code available to be reused  another time, be able to use the code
at different locations along the profile, want the code to to do some machine moves prior and after the program to your liking......
or maybe use inputs on the screen and Mach will run the code........etc

I just listed the above to give you a flavor of "repetitive" use to enlighten the learning experience . Each one will require a different level of
knowledge and programming techniques.

SO here is what i am suggesting:
1.Get a good reference book on programming......Peter Smid - CNC Programming Handbook
2.Try each of the lathe wizards and look at the generated code. ( there is one to turn down a diameter) Much can be gained from reviewing
   the code.

 RICH