Fanuc G72 Facing Cycle
If you have spent some time on cnc machine with fanuc control in cnc machine workshop, then you might surely have used G72 Canned Cycle Facing and cnc turning cycle G71.
Because cnc cycle programming in fanuc cnc control is just easy.
Why do we use cnc cycles read pros and cons of cnc programming cycles. In this post I am going to elaborate the use, and programming of the G72 Canned Cycle Facing on Fanuc cnc control.
For Fanuc G71 turning cycle read this article about G71.
Fanuc cnc control is widely used, no doubt one of the most favorite cnc control of cnc programmers, due to its ease of programming and durability.
Programming
G72 W R G72 P Q U W
Parameters
First Block
| Parameter | Description |
|---|---|
| W | Depth of cut. |
| R | Return value after a cut is complete. |
Second Block
| Parameter | Description |
|---|---|
| P | Contour start block number. |
| Q | Contour end block number. |
| U | Finishing allowance in x-axis. |
| W | Finishing allowance in z-axis. |
| S | Spindle speed during G71 cycle. |
| 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 second 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 speeds for roughing cuts and finish cut.
Fanuc G72 Facing Cycle Example
CNC Fanuc G72 Canned Cycle Facing
N5 G00 X65 Z42 N6 G72 W2 R2 N7 G72 P8 Q9 U0 W0 F0.3 N8 G00 Z30 N9 G01 X20
