Fanuc G72 Facing Cycle One-line Format
Fanuc cnc control has many versions with variety of different cnc programming techniques and styles.
Facing Canned Cycle
As some fanuc cnc controls (Fanuc OT/16T/21T) use Two-line format for canned-cycles (G71, G72 etc).
But other fanuc cnc controls (Fanuc 10T/15T) use One-line format for canned cycles (G71, G72).
Below is the Fanuc G72 facing cycle One-line format version described in full detail.
Programming
G72 P… Q… U… W… D… F… S…
Parameters
| Parameter | Description |
|---|---|
| P | Contour start block number. |
| Q | Contour end block number. |
| U | Finishing allowance in x-axis. |
| W | Finishing allowance in z-axis. |
| D | Depth of cut. |
| F | Feed-rate (overrides the feed-rates given between P block and Q block) |
| S | Spindle Speed (overrides the spindle speed given between P block and Q block) |
Notes
P & Q – The cnc program blocks between the P block number and Q block number will be repeated until the end dimension is not met.
F (feed-rate) – The benefit of using F (feed-rate) in G72 block is that during facing cycle machine will use this feed-rate, and will ignore any feed-rates given between P block and Q block program.
The feed-rate given between P block and Q block program will only be used if you call G70 Finishing Cycle later in program with same P block and Q block numbers.
This is very handy way gives cnc machinist opportunity to keep different feed-rates for “rough facing cuts” and “final finishing cut”.
S (spindle speed) – works the same way to keep different spindle speeds for roughing cuts and finish cut.
