Manual

Grooving/Cutoff Cycles
Chapter 23
23-7
The format for this cycle is:
G77X__Z__I__K__F__D__;
Where : Is :
Z__ thelocation wherethe last grooveis cut. If onlyone grooveis to be cut donot
program Z. This may beprogrammed as either an incremental or absolute value.
X__ thetotal depth of thegroove from the X coordinateposition of thetool priorto the
execution of the G77 block. If this cycle is to be used as a cut off cycle the depth
programmed here should drive thetool through thecenter or insidediameter of the
part. If a cut off is being made from theinside of thepart, it should drivethe tool
beyond the outside diameter of the part. This valuerepresents thelocation of the
bottom of thegroove cut. It may beprogrammed aseither an incrementalor
absolute value and is also affected by radiusor diameter mode(G07 or G08).
K__ thedistance betweeneach groove. If the distancebetween thelocation of thelast
groove (programmed with Z) and thenext to thelast groove isless thanthe value
programmed with K, then the K value isnot used todetermine theposition of the
last groove. The last grooveis always cut at thelocation programmedwith Z. The
K parameter isalways programmedas anincremental valueregardless of the
current mode of the control.
I__ theamount that the cuttingtool infeeds intothe workpiecewith each step. The step
is followedby aretract of amount e (set in AMP bythe system installer). The
cutting tool then infeedsinto theworkpiece anamount I + e, retracts an amount e,
infeeds I +e, retracts e, etc. This repeats untilthe totalprogrammed depthof the
groove X is reached. When thisdepth isreached thecutting toolstops infeeding
and either shifts an amount D (if programmed) or retractsto thestarting coordinate
at rapid feedrate. The I-wordis always programmedas anincremental value
regardless of thecurrent mode of thecontrol.
F optional inthe groovingblock. If programmed thevalue enteredwith thisparameter
replaces thecurrently activefeedrate usedwhen infeedinginto thepart. If F isnot
programmed the currently activefeedrate isused.
D__ thesize of theincremental shift move made by thetool whenthe fulldepth of acut
off hasbeen reached. This parameter must beprogrammed evenif its valueis zero
when not using this cycleas acutoff. A valueother than zerois assignedto Donly if
the grooving cycle is being usedas acut off cycle. It is alwaysan incrementalvalue
regardless of thecurrent mode. The sign of the value programmedwith the D
parameter determinesthe shift directionand shouldmove thetool awayfrom the
part. Programming this shift duringa cutoff move helps to providea good finish
since the cutting tool is not touchingthe part whenit is retractedat the rapid
feedrate.
CAUTION: The shift programmed with a D parameter is
executed as a rapid move. Make sure that the cutting tool is
clear to shift at the end of the grooving cycle.