Manual

Allen-Bradley 7300 Series CNC
Tape Compatibility
Appendix D
D-5
The format for the G29 block is:
G29__D__K__I__Z__L__F
Where: Specifies:
D returnpass clearance, whichis thedistance betweenthe initialwork surfaceand the
starting point. D value must always be programmedas anincremental distance,
regardless of thecurrent operating mode.
K threadlead, which isthe distancethe threadcutting toolis tomove alongthe Zaxis per
revolution of the spindle. The threadlead isalways programmedin unitsof inches per
revolution (IPR) in theInch format mode(G70), or millimeters per revolution(MMPR) in
the Metric format mode (G71).
Does not needto beprogrammed forroughing cycle.
I threadlead for atapered thread, whichis thedistance anddirection thethread cutting
tool isto movealong theX axisper revolution of thespindle. The thread lead is always
programmed in units of inchesper revolution(IPR) in theInch format mode(G70), or
millimeters perrevolution (MMPR)in theMetric format mode(G71). The I-word
determines theangle of atapered thread. If the angle is known, I-word canbe
calculated with the following formulas:
I-word = K-word* Tan0
Assign a value to I only if cuttingtapered threads (I ¹0).
Length of the roughing pass for Zaxis roughing cycle, I is the distancealong the X axis.
Does not needto beprogrammed forsingle axis roughing.
Z lengthof the thread. For Absolute Programmingmode, the thread length is programmed
as theZ axisposition of theend of thethread. For Incremental Programming mode, the
thread length is programmedas adistance measuredparallel tothe Zaxis from the
infeed endpoint to the end of thethread.
Length of the roughing pass for roughingcycle, which isthe distancemeasured parallel
to the Z axis.
L pullout distance, whichis thedistance from theprogrammed endof the threadto the
point at which the thread cutting tool isto start pullingout from theworkpiece. This
distance is measured parallelto theZ axis. If no L-wordis programmed, then the tool
does not pullout until it reachesthe programmedend of thethread. L-word must always
be programmed as anincremental distance, evenin theAbsolute Programmingmode.
F feedrateof the returnpath, which isthe rateat which thetool movesaway from thepart
and returns to thestart-point of the cyclefor thenext infeed. The infeedrate isalways
programmed in units/inches perminute (IPM)in the Inch mode, or millimeters/minute
(MMPM) inthe Metricmode. If no F-wordis programmedin theG29 block, thelast
programmed feedrate before the G28block is used.