G72 Facing Cycle One-line Format for Fanuc 10T 11T 15T

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

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

ParameterDescription
PContour start block number.
Q Contour end block number.
UFinishing allowance in x-axis.
WFinishing allowance in z-axis.
DDepth of cut.
FFeed-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.