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G-Code programming the Fanuc 20T control.

Heinz R. Putz

Stainless
Joined
Mar 16, 2006
Location
Columbus, Ohio
A shop in NC bought a lathe with the Fanuc 20T, they have no CNC experience at all and ask me for advice.
I have trained shops on Fanuc lathes and mills for many years, but I did not know there even was a 20T control.
They need help, any example of a typical face-turn lathe part would be greatly appreciated.
Any knowledge at all will help.
Heinz.
 
A shop in NC bought a lathe with the Fanuc 20T, they have no CNC experience at all and ask me for advice.
I have trained shops on Fanuc lathes and mills for many years, but I did not know there even was a 20T control.
They need help, any example of a typical face-turn lathe part would be greatly appreciated.
Any knowledge at all will help.
Heinz.

Hello Heinz,
The 20T control uses the same Syntax as any other Fanuc control circa that time. The only significant difference in the Syntax and Format of various Fanuc controls is when Offset Programming was introduced to set the Coordinate System and the two line Format for Multi-repetitive cycles. Accordingly, I'm sure you would have many program examples for other controls such as 16T and onward. The 20T uses the two line Format for Multi-repetitive cycles (Standard FS16 Format).

I believe the 20T control was not sold in the US and that any examples there would have been bought from other countries. I believe also that the FS20 control was only offered as a two axis control.


Regards,

Bill
 
I just walked over and took a look at a 18-T it uses work shift, geometry, wear and two line canned cycles. What else could be different. I'd lay odds it'll run a 18-T programs. Can't say as if I've ever heard of the 20-T myself either?

Maybe get them to turn it on and see if anything is in the directory take some pictures of programs just to kinda give you a look at them. Really I can't imagine what would be so different? The addition of G54-G59 Maybe?

Brent
 
A shop in NC bought a lathe with the Fanuc 20T, they have no CNC experience at all and ask me for advice.
I have trained shops on Fanuc lathes and mills for many years, but I did not know there even was a 20T control.
They need help, any example of a typical face-turn lathe part would be greatly appreciated.
Any knowledge at all will help.
Heinz.


A example of a turn program on a fanuc 20T
%
OFM1( FILENAME = FM1)
N20 G20 G40
N25 G28 U0
N30 G28 W0
( OPERATION: ROUGH TURN TURN1 )
N40 T101
N45 G50 S3000
N50 G96 S800 M4
N55 G0 X2.19 Z0.0687 M8
N60 G1 Z-0.5313 F0.04
N65 X2.25
N70 X2.2854 Z-0.5136
N75 G0 Z0.0687
N80 G1 X2.13
N85 Z-0.5313
N90 X2.19
N95 X2.2254 Z-0.5136
N100 G0 Z0.0687
N105 G1 X2.07
N110 Z-0.5313
N115 X2.13
N120 X2.1654 Z-0.5136
N125 G0 Z0.0687
N130 G1 X2.01
N135 Z-0.5313
N140 X2.07
N145 X2.1054 Z-0.5136
N150 G0 Z0.0687
N155 G1 X1.95
N160 Z-0.5313
N165 X2.01
N170 X2.0454 Z-0.5136
N175 G0 Z0.0687
N180 G1 X1.89
N185 Z-0.5313
N190 X1.95
N195 X1.9854 Z-0.5136
N200 G0 Z0.0687
N205 G1 X1.83
N210 Z-0.5313
N215 X1.89
N220 X1.9254 Z-0.5136
N225 G0 Z0.0687
N230 G1 X1.77
N235 Z-0.5313
N240 X1.83
N245 X1.8654 Z-0.5136
N250 G0 Z0.0687
N255 G1 X1.71
N260 Z-0.5313
N265 X1.77
N270 X1.8054 Z-0.5136
N275 G0 Z0.0687
N280 G1 X1.65
N285 Z-0.5313
N290 X1.71
N295 X1.7454 Z-0.5136
N300 G0 Z0.0687
N305 G1 X1.59
N310 Z-0.5313
N315 X1.65
N320 X1.6854 Z-0.5136
N325 G0 Z0.0687
N330 G1 X1.53
N335 Z-0.5313
N340 X1.59
N345 X1.6254 Z-0.5136
N350 G0 Z0.0687
N355 G1 X1.47
N360 Z-0.5313
N365 X1.53
N370 X1.5654 Z-0.5136
N375 G0 Z0.0687
N380 G1 X1.41
N385 Z-0.5313
N390 X1.47
N395 X1.5054 Z-0.5136
N400 G0 Z0.0687
N405 G1 X1.35
N410 Z-0.5313
N415 X1.41
N420 X1.4454 Z-0.5136
N425 G0 Z0.0687
N430 G1 X1.29
N435 Z-0.5313
N440 X1.35
N445 X1.3854 Z-0.5136
N450 G0 Z0.0687
N455 G1 X1.23
N460 Z-0.5313
N465 X1.29
N470 X1.3254 Z-0.5136
N475 G0 Z0.0687
N480 G1 X1.17
N485 Z-0.5313
N490 X1.23
N495 X1.2654 Z-0.5136
N500 G0 Z0.0687
N505 G1 X1.11
N510 Z-0.5313
N515 X1.17
N520 X1.2054 Z-0.5136
N525 G0 Z0.0687
N530 G1 X1.05
N535 Z-0.5313
N540 X1.11
N545 X1.1454 Z-0.5136
N550 G0 Z0.0687
N555 G1 X0.99
N560 Z-0.5313
N565 X1.05
N570 X1.0854 Z-0.5136
N575 G0 Z0.0687
N580 G1 X0.93
N585 Z-0.5313
N590 X0.99
N595 X1.0254 Z-0.5136
N600 G0 Z0.0687
N605 G1 X0.87
N610 Z-0.5313
N615 X0.93
N620 X0.9654 Z-0.5136
N625 G0 Z0.0687
N630 G1 X0.81
N635 Z-0.5313
N640 X0.87
N645 X0.9054 Z-0.5136
N650 G0 Z0.0687
N655 G1 X0.75
N660 Z-0.5313
N665 X0.81
N670 X0.8454 Z-0.5136
N675 G0 Z0.0687
N680 G1 X0.69
N685 Z-0.5313
N690 X0.75
N695 X0.7854 Z-0.5136
N700 G0 Z0.0687
N705 G1 X0.63
N710 Z-0.5313
N715 X0.69
N720 X0.7254 Z-0.5136
N725 G0 Z0.0687
N730 G1 X0.57
N735 Z-0.5313
N740 X0.63
N745 X0.6654 Z-0.5136
N750 G0 Z0.0687
N755 G1 X0.51
N760 Z-0.5313
N765 X0.57
N770 X0.6054 Z-0.5136
N775 G0 Z0.1
( OPERATION: FINISH TURN TURN1 )
N785 G0 X0.5
N790 G50 S3000
N795 G96 S1200
N800 G0 X0.5 Z0.1 M8
N805 G1 Z-0.5313 F0.02
N810 X0.6856 Z-0.4384
N815 G0 X2.45
N820 G28 U0
N825 G28 W0
N830 M30
%
 
A example of a turn program on a fanuc 20T
%
OFM1( FILENAME = FM1)
N20 G20 G40
N25 G28 U0
N30 G28 W0
( OPERATION: ROUGH TURN TURN1 )
N40 T101
N45 G50 S3000
N50 G96 S800 M4
N55 G0 X2.19 Z0.0687 M8
N60 G1 Z-0.5313 F0.04
N65 X2.25
N70 X2.2854 Z-0.5136
N75 G0 Z0.0687
N80 G1 X2.13
N85 Z-0.5313
N90 X2.19
N95 X2.2254 Z-0.5136
N100 G0 Z0.0687
N105 G1 X2.07
N110 Z-0.5313
N115 X2.13
N120 X2.1654 Z-0.5136
N125 G0 Z0.0687
N130 G1 X2.01
N135 Z-0.5313
N140 X2.07
N145 X2.1054 Z-0.5136
N150 G0 Z0.0687
N155 G1 X1.95
N160 Z-0.5313
N165 X2.01
N170 X2.0454 Z-0.5136
N175 G0 Z0.0687
N180 G1 X1.89
N185 Z-0.5313
N190 X1.95
N195 X1.9854 Z-0.5136
N200 G0 Z0.0687
N205 G1 X1.83
N210 Z-0.5313
N215 X1.89
N220 X1.9254 Z-0.5136
N225 G0 Z0.0687
N230 G1 X1.77
N235 Z-0.5313
N240 X1.83
N245 X1.8654 Z-0.5136
N250 G0 Z0.0687
N255 G1 X1.71
N260 Z-0.5313
N265 X1.77
N270 X1.8054 Z-0.5136
N275 G0 Z0.0687
N280 G1 X1.65
N285 Z-0.5313
N290 X1.71
N295 X1.7454 Z-0.5136
N300 G0 Z0.0687
N305 G1 X1.59
N310 Z-0.5313
N315 X1.65
N320 X1.6854 Z-0.5136
N325 G0 Z0.0687
N330 G1 X1.53
N335 Z-0.5313
N340 X1.59
N345 X1.6254 Z-0.5136
N350 G0 Z0.0687
N355 G1 X1.47
N360 Z-0.5313
N365 X1.53
N370 X1.5654 Z-0.5136
N375 G0 Z0.0687
N380 G1 X1.41
N385 Z-0.5313
N390 X1.47
N395 X1.5054 Z-0.5136
N400 G0 Z0.0687
N405 G1 X1.35
N410 Z-0.5313
N415 X1.41
N420 X1.4454 Z-0.5136
N425 G0 Z0.0687
N430 G1 X1.29
N435 Z-0.5313
N440 X1.35
N445 X1.3854 Z-0.5136
N450 G0 Z0.0687
N455 G1 X1.23
N460 Z-0.5313
N465 X1.29
N470 X1.3254 Z-0.5136
N475 G0 Z0.0687
N480 G1 X1.17
N485 Z-0.5313
N490 X1.23
N495 X1.2654 Z-0.5136
N500 G0 Z0.0687
N505 G1 X1.11
N510 Z-0.5313
N515 X1.17
N520 X1.2054 Z-0.5136
N525 G0 Z0.0687
N530 G1 X1.05
N535 Z-0.5313
N540 X1.11
N545 X1.1454 Z-0.5136
N550 G0 Z0.0687
N555 G1 X0.99
N560 Z-0.5313
N565 X1.05
N570 X1.0854 Z-0.5136
N575 G0 Z0.0687
N580 G1 X0.93
N585 Z-0.5313
N590 X0.99
N595 X1.0254 Z-0.5136
N600 G0 Z0.0687
N605 G1 X0.87
N610 Z-0.5313
N615 X0.93
N620 X0.9654 Z-0.5136
N625 G0 Z0.0687
N630 G1 X0.81
N635 Z-0.5313
N640 X0.87
N645 X0.9054 Z-0.5136
N650 G0 Z0.0687
N655 G1 X0.75
N660 Z-0.5313
N665 X0.81
N670 X0.8454 Z-0.5136
N675 G0 Z0.0687
N680 G1 X0.69
N685 Z-0.5313
N690 X0.75
N695 X0.7854 Z-0.5136
N700 G0 Z0.0687
N705 G1 X0.63
N710 Z-0.5313
N715 X0.69
N720 X0.7254 Z-0.5136
N725 G0 Z0.0687
N730 G1 X0.57
N735 Z-0.5313
N740 X0.63
N745 X0.6654 Z-0.5136
N750 G0 Z0.0687
N755 G1 X0.51
N760 Z-0.5313
N765 X0.57
N770 X0.6054 Z-0.5136
N775 G0 Z0.1
( OPERATION: FINISH TURN TURN1 )
N785 G0 X0.5
N790 G50 S3000
N795 G96 S1200
N800 G0 X0.5 Z0.1 M8
N805 G1 Z-0.5313 F0.02
N810 X0.6856 Z-0.4384
N815 G0 X2.45
N820 G28 U0
N825 G28 W0
N830 M30
%
What happened to G71/G70
 
When teaching CNC basics I find it best to stay very far away from canned cycles.
Master G00 and G01 X,Y and Z (and A,B,C as needed) first.
Then G02, G03, tool comps, leadin/out and then canned shortcuts.
Perhaps I am just too old as I learned on NC not CNC. You can do anything with G00, G01, G02, G03 and maybe a G04 tossed in.
Sure the code is much longer but Baby steps. Knowing it the basic way and you will understand how the canned cycles work.
One learns to crawl, walk, and then run. Trying to run when still at the crawl age means falling hard and crying.
Bob
 
Last edited:
When teaching CNC basics I find it best to stay very far away from canned cycles.
Master G00 and G01 X,Y and Z (and A,B,C as needed) first.
Then G02, G03, tool comps, leadin/out and then canned shortcuts.
Perhaps I am just too old as I learned on NC not CNC. You can do anything with G00, G01, G02, G03 and maybe a G04 tossed in.
Sure the code is much longer but Baby steps. Knowing it the basic way and you will understand how the canned cycles work.
One learns to crawl, walk, and then run. Trying to run when still at the crawl age means falling hard and crying.
Bob
That is correct. My approach in my new book has been on similar lines. The person may not even be knowing the difference between G codes and M codes.

A journey to thousand miles starts with the first step.
 








 
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