
B--63003EN--1/02
6. INTERPOLATION FUNCTION
493
Each time the spindle speed command for the first spindle changes or P
and Q are re--specified in a G51.2, the clamp speed is checked to
determine whether to issue P/S alarm No. 5018.
Note that a reset can clear the alarm with the speed clamped.
(A rotation speed ratio of P:Q cannot be maintained with the speed
clamped. Bit 2 (QCL) of DGN No. 471 indicates whether the speed is
clamped.)
Although this function is based on the G--code system, it is necessary to
add or change PMC ladder sequences because control on the part of the
spindle is also required (See signals in Section 6.10.2).
This example of polygonal turning with two spindles produces a square
using single--edged cutting tools (for roughing and finishing).
.
Mfj;
Tff
αα ;
Step 1.
Mount a roughing tool on the polygon syn-
chronization axis (second spindle as tool
rotation axis).
G00 X100. Z20. M03 S1000
;
.
.
Step 2.
Rotate the workpiece (with the first spindle
as the master axis at 1000 rpm)
G51.2P1Q2;
.
.
.
.
.
.
.
.
.
.
.
.
Step 3.
Start rotating the tool.
Energize the second spindle in response to
the polygon synchronization under way sig-
nal using the PMC ladder.
After accelerating the second spindle as the
polygon synchronization axis to 2000 rpm,
perform phase adjustment (Execute R0 to
omit an R value.).
By checking PSYC<F0063#7>, the PMC
ladder can detect when the polygon syn-
chronization mode is entered. During the
polygon synchronization mode, the PMC
ladder controls SAR<G0029#4> based on
the speed arrival signal PSAR<F0063#2>
during the polygon synchronization mode.
G01 X80. F10. ;
.
.
Step 4.
Starts cutting along the X--axis after
SAR<G0029#4> becomes logical 1 in sig-
nalcontrolatstep3.
G04 P4000 ;
.
Step 5.
Polygonal turning (roughing 1)
G00 X100. ;
.
Step 6.
Retract the tool along the X--axis.
G51. 2 R180 ;
.
Step 7.
Change the phase by 180 degrees.
[Repeat steps 4, 5, and 6.]
.
Step 8.
Polygonal turning (roughing 2)
G50. 2 ;
Mj ;
T jj ;
.
Step 9.
Release the polygon synchronization mode.
Change to a finishing tool.
D PMC sequence
D Example of polygonal
turning with two spindles