12. FUNCTIONS TO SIMPLIFY
PROGRAMMING
B–63172EN/01
NC FUNCTION
78
Tapping a deep hole in rigid tapping mode may be difficult due to chips
sticking to the tool or increased cutting resistance. In such cases, the peck
rigid tapping cycle is useful.
In this cycle, cutting is performed several times until the bottom of the
hole is reached. Two peck tapping cycles are available: High–speed peck
tapping cycle and standard peck tapping cycle. These cycles are selected
using the PCP bit (bit 5) of parameter 5200.
G84, G74
G84 (or G74) X_ Z_ R_ P_ Q_ F_ ;
X_ : Hole position data
Z_ : The distance from point R to the bottom of the hole and the
position of the bottom of the hole
R_ : The distance from the initial level to point R level
P_ : Dwell time at the bottom of the hole and at point R when a
return is made
Q_ : Depth of cut for each cutting feed
F_ : The cutting feedrate
S High–speed peck tapping cycle
(Parameter PCP(No.5200#5=0))
d
q
q
q
d
(1)
(2)
d
q
q
q
d
(1)
(2)
S Peck tapping cycle
(Parameter PCP(No.5200#5=1))
(3)
(1) The tool operates at a normal
cutting feedrate. The normal time
constant is used.
(2) Retraction can be overridden.
The retraction time constant is
used.
(1) The tool operates at a normal
cutting feedrate. The normal time
constant is used.
(2) Retraction can be overridden.
The retraction time constant is
used.
(3) Retraction can be overridden.
The normal time constant is used.
Point Z
Initial level
Point R
d=retraction distance
Point R level
d=cutting start distance
Initial level
Point R
Point Z
Point R level
During a rigid tapping cycle, CNC checks
whether the pulse distribution is per-
formed or not and start the next operation
at the end of each operation of (1) and
(2) in the peck tapping cycle.
12.2.3
Peck Rigid Tapping
Cycle (G84 or G74)
Format