Programming instructions

ADT-CNC4620 Programming Manual
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receives the signals from principal axis encoder Z (origin), it moves X axis or Z axis
and starts thread processing, therefore, the processing of same thread can be finished
through roughing and finishing as long as the principal axis rotation isn’t changed.
z Since X axis and Z axis have acceleration and deceleration process in the beginning
and at the end of thread cutting, the pitch error is large at this moment, and therefore
acceleration pitch P must exist before the long axis start point and deceleration pitch
D (usually called as retreating groove) must exist after the end point of the long axis
during actual thread cutting, i.e. programmed thread length is longer than actual
thread length. Thread cutting length includes P, D; similarly, the end position of the
short axis must have back amount V, i.e. at the end position of thread cutting, the
short axis exits thread cutting in V back amount, as shown in the figure below.
For example:
Thread pitch: 4mm. P = 3.5mm, D = 3.5mm, V=1, total cutting depth 1mm (single side),
cut in two times
G00 X28 Z3; (cut 0.5mm in the first time)
G32 X51 W-77 F4.0 P3.5 D3.5 V1; (taper thread first cutting)
G00 X55; (tool exits)
W77; (Z returns to the start point)
X27; (cut another 0.5mm in the second time)
G32 X50 W-77 F4.0; (taper thread second cutting)
G00 X55; (tool exits)
W77; (Z returns to the start point)
As in Fig. 3-7-3:
Start point End point
Fig. 3-7-3
z Under the condition that the start point, end point and thread pitch of G32 are fixed, the
moving speed of X axis and Z axis during thread cutting depends on the principal axis
rotation, and doesn’t relate to cutting feeding ration. During thread cutting, principal
axis ratio control is valid; when principal axis rotation is changed, the pitch error
increases due to acceleration/deceleration of X axis and Z axis, therefore, do not adjust
the principal axis rotation during thread cutting or stop the principal axis (or else the
tool and workpiece will be damaged).
z During thread cutting, the long axis increment should be larger than the value of (P+D),
and the actual thread length of the long axis should be larger than pitch F.
z When the system is reset, stopped in emergency or alarms, thread cutting stops