TOMATECH AUTOMATION
G75 R0.5 F150; (Machining cycle)
G75 X40 Z-50 P6000 Q3000; (X tool infeed 6mm every time, tool retraction 0.5mm,
rapid returning to starting point (X125) after infeeding to end point (X40), Z tool infeed
3mm and cycle the above-mentioned steps to continuously run programs)
G0 X150 Z50; (Return to starting point of machining)
M30; (End of program)
3.21 Thread Cutting Commands
TAC-100XT CNC system can machine many kinds of thread cutting, including metric/inch
single,multi threads, thread with variable lead and tapping cycle. Length and angle of
thread run-out can be changed, multiple cycle thread is machined by single sided to
protect tool and improve smooth finish of its surface. Thread cutting includes: continuous
thread cutting G32, thread cutting with variable lead G34, Z thread cutting G33, Thread
cutting cycle G92, Multiple thread cutting cycle G76.
The machine used for thread cutting must be installed with spindle encoder whose pulses
are set by No.070m. Drive ratio between spindle and encoder is set by No.110 and
No.111. X or Z traverses to start machine after the system receives spindle signal per rev
in thread cutting, and so one thread is machined by multiple roughing, finishing without
changing spindle speed.
The system can machine many kinds of thread cutting, such as thread cutting without tool
retraction groove. There is a big error in the thread pitch because there are the
acceleration and the deceleration at the starting and ending of X and Z thread cutting, and
so there is length of thread lead-in and distance of tool retraction at the actual starting and
ending of thread cutting.X, Z traverse speeds are defined by spindle speed instead of
cutting feedrate override in thread cutting when the pitch is defined. The spindle override
control is valid in thread cutting. When the spindle speed is changed, there is error in pitch
caused by X and Z acceleration/deceleration, and so the spindle speed cannot be
changed and the spindle cannot be stopped in thread cutting, which will cause tool and
workpiece to be damaged.
3.21.1 Thread cutting with constant lead G32
Command format: G32 X(U)_ Z(W)_ F(I)_ J_ K_ Q_
Command function: The path of tool traversing is a straight line from starting point to end
point as Fig.3-33; the longer moving distance from starting point to end point(X in radius
value) is called as the long axis and another is called as the short axis. In course of motion,
the long axis traverses one lead when the spindle rotates one revolution, and the short
axis and the long axis execute the linear interpolation. Form one spiral grooving with
variable lead on the surface of workpiece to realize thread cutting with constant lead.
Metric pitch and inch pitch are defined respectively by F, I. Metric or inch straight, taper,
end face thread and continuous multi-section thread can by machined in G32.
Command specifications:
G32 is modal;
Pitch is defined to moving distance when the spindle rotates one rev(X in radius);
Execute the straight thread cutting when X coordinates of starting point and end point are
the same one(not input X or U);
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