CNC Z32 - Programming Guide (LATHES)
G883: Deep drilling with chip extraction
Z (or X):
hole end position
J:
approaching position. It is the machining starting
position
E:
final return position.
NT:
dwell time at hole end
K:
depth increment before chip extraction
I
: reduction of pass increment
NM
: minimum pass depth
The operation logic of the parameters K, I and NM is the following:
The depth of the first pass is set with the K parameter.
The I parameter defines the reduction of pass depth.
The NM parameter sets the minimum value of the pass depth.
For example, suppose to choose the following parameters:
K50 I20 NM5
That means:
The first drilling is equal to the K value (50)
The drilling length reduction is equal to the I value (20)
The minimum allowed drilling depth is defined by the NM parameter (5).
The drilling depth will then vary as follows:
1
st
pass = 50
2
nd
pass: reduced by the value I = 50-20 = 30
3
rd
pass: still reduced by the value I = 30-20 = 10
4
th
pass: still reduced by the I value 10-20 = -10. The resulting value is smaller than the minimum
pass depth, therefore the value is set to the NM value (5).
5
th
and subsequent passes: with a constant increment of 5.
Note: To get constant depth increments, program I = 0.
NQ:
chip extraction position
NN:
dwell at chip extraction position
NS:
safety distance for in hole repositioning. If a null value is programmed, or if the NS parameter is
not programmed, a default value of 1 is assumed.
F:
Feed
Note:
In case of holes drilled in X direction, the values X, J, E, K, I, NM, NQ, NS are considered as
diametric or radial, depending on the active mode when the drilling is programmed.
feed F
G0
Z (X)
NT
NN
NQ
K
NS
J
E
6.1.4
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