Programming instructions

ADT-CNC4620 Programming Manual
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G92 thread cutting notice:
z The machine tool must be installed with principal axis encoder for thread cutting; the
transmission ration of principal axis encoder and the principal axis is 1:1; the principal
axis encoder outputs A/B differential signal and Z signal (conversion signal) with 90°
phase difference. When cutting thread, the system starts thread processing after
receiving principal axis encoder Z signal. Therefore, the processing of same thread can
be finished through roughing and finishing of several connected G92 blocks 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. The thread
back function of G92 function can be used to process the thread without retreating
groove.
z Under the condition that the start point, end point and thread pitch of G92 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, and after feeding maintenance operation is executed, thread
cutting doesn’t stop.
z Thread cutting is invalid when single block is running, and the running pauses after the
first non-thread cutting in the thread cutting cycle is executed. When the system is reset,
stopped in emergency or alarms, thread cutting stops immediately.
As in Fig. 3-10-7:
Linear thread
Fig. 3-10-7
Program:
O3201
M03S500
G00X9.72Z2;
G32W-20 F1.75
G00X20
Z20
M30