Need Help!- Fanuc Series 20-TA (G90 canned cycle)

[firekoe]

i am wanting to use a G90 canned cycle and was wondering how to input the data. just starting out with cnc lathe with a fanuc control so any help would be great

thanks

[leggazoid]

G90 is a turn/bore cycle.

turn example. starting with a 5" part turn down to 4.9" length 1".

GO X5. Z.1
G90 X4.9 Z-1. F.01

this command will do the same as these moves

G0 X5. Z1.
G0 X4.9
G1 Z-1. F.01
G1 X5. F.01
G0 Z.1

Now that saved some typing, but there is more...

GO X5. Z.1
G90 X4.9 Z-1. F.01
X4.8
X4.7
G0 G28 U0 W0 M5

This example will continue cutting by the value specified. This can save typing, make programs shorter, easier to read. The downside is at the end of each cut, it will feed up to 5". This can be a waste of time. A G71 would work better in some cases.

Regards,
Ken

[firekoe]

my operator's manual does not show a G71 what is it and how is it utilized and thanks on the G90 info that clears thing up

[sinha_nsit]

See the attachment for more info on G90 which can also be used for taper turning with an R-word.

Yes. Because of radial retraction at feedrate, subsequent calls of G90 become inefficient. In such cases, change the radial position of the start point after a few calls.

G71 may be an option.

[leggazoid]

Here is a control similar to yours, this is a tool builders manual.

http://www.snkamerica.com/Prod-pdf/G...tor_Guide2.pdf

What would help you a lot is a fanuc operator's manual for your specific control. They can be ordered from fanuc, but I don't know the cost.