Acu-Rite CNC 3500i User Manual

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11 G-Code Edit, Help, & Advanced Features
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.5 F
our Axis Pr
ogr
a
mming
Example 3: Mill
Mount a fourth axis as described above. Mount a part 4” in diameter 
and 8” long on the face of the rotary table. Support the part on the 
X+ end by a live center. The part has a 0.25”, 45° chamfer on one 
end. Shortest Distance is set to on. This prevents the need to 
unwind the U-axis, saving operation time.  
Table 15-3 shows a thread-milling example. Assume that a 4-8 UN 
2A thread must be milled from the right end, 6” long. The tool is 
tapered to conform to the thread. Set X0 at the right end, Y0 at the 
cylinder's center line, U0 at a pre-milled keyway on the cylinder. 
Measure the tool offset from the top of the part (with Y axis at 0).
The X start position is one pitch (0.125 in.) to the right of X0, so that 
the tool enters the work smoothly.
* 4-AX-THD
* SET Shortest Distance TO "on"
G90 G70 G0 M5
G28 Z0
G53 O1
G0 X0 Y0 U0
T1 * SPECIAL THD-TOOLS3500
S3500
M3
G0 X.125 Y0 U0
Z.1
G1 Z-.075 F20
* SET Shortest Distance TO "on"
* THIS IS TO PREVENT THE NEED TO UNWIND U
* U AXIS MOVE IS
* (360 X 8 PITCH X 6" LONG)
* + 360 FOR 1 TURN X.125 LEAD-IN
* U MOVE WILL BE 17,640.00 DEGREES
* OR 49 TURNS
G91 G1 X-6.125 U((360*8*6)+360)
G90 G0 M5
G28 Z0
X0 Y0 U0
M2