Skip to main content

Fundamentals of G72 Cycle


Introduction to G72 cycle

This cycle generates a part shape from a cylindrical raw material, with cuts perpendicular

to the axis. The cycle definition has the part shape, depth of cut, finish allowance and couple of other parameters.

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.

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

ParameterDescription
WDepth of cut.
RReturn value after a cut is complete.

Second Block

ParameterDescription
PContour start block number.
QContour end block number.
UFinishing allowance in x-axis.
WFinishing allowance in z-axis.
SSpindle speed during G71 cycle.
FFeed-rate (overrides the feed-rates given between P block and Q block)
SSpindle 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

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
For more information about G71 visit
https://vedic8211.blogspot.com/2020/06/fundamentals-of-g71-cycle.html

Comments

Post a Comment

Popular posts from this blog

Fanuc Face grooving using G74

Fundamentals:- The cycle G74 stands for longitudinal cutting process. Where we remove material from face ether performing as drilling cycle or face grooving, the cycle is beneficial to cut stubborn materials like stainless steels. Because of complete material removal motion. In G74 cycle we can cut through along with 'Z' axis as well as 'X' axis, also can use on turnmill operations while drilling off centre drills. Format of G74:- ________ G74 R G74 P Q X Z F ________ R- retraction amount. P- shifting value while cutting along X axis in micron. Q- Depth of cut in micron. X- Cutting last destinations along X axis. Z- Cutting last destinations along Z axis. F- Feed. Note:- shifting value 'P' should not exceed the width of grooving tool. If tool width is 4mm then shifting value should be 3.5mm. Example:-   G00 X40.0 Z2.0; G74 R0.5 (shifting value); G74 P3500( 3.4 shift value) Q500 (depth of cut) X52.0 Z-7.0 F0.07; G00 Z10.0
Post a Comment
Read more

Fanuc grooving cycle G75

Fundamentals This cycle does a peck drilling operation for grooving or drilling perpendicular to the axis. The cycle can actually be used to cut multiple grooves, or (on a machine with a C-axis and live tools) drill multiple radial holes at various positions along the length, The explanation here is restricted to cutting a single groove. Structure ______ G75  R G75  X  P  F _______ R= Retreat amount after each peck, radial distance. X= X coordinate of groove bottom (Diameter to cut).  P= Peck depth, radial distance in micron. F= Feed rate. We can remove material performing single groove same as insert thickness as well as more than that. Example of single groove as insert thickness ________ G00 X54.0 Z-20.0; G75 R0.5; G75 X30.0 P1000 F0.1; G00 X100.0 Z50.0; _____ Example of Groove more than insert thickness Let the groove width is 5mm of the above drowning ________ G00 X54.0 Z-20.0;   (using 3mm insert thickness) G75 R0.5; G75 X30.0 Z-25.0 P1000 Q2500 ...
Post a Comment
Read more