New bug in turning threads, junk G-code
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I don't know if multi start threads are part of new update because I haven't used Fusion to produce threads in a long time.
Anyway, looking at what's new or new to me, I tried 3 starts, 1-20 thread on 1 inch diameter stock. For sake of illustration, using 5 passes in each G92 cycle.
The rule states that pitch is multiplied by number of starts, so.....
1/20 = .05 x 3= .15, feed rate in each cycle should be F.15
After first cycle, each of the two remaining cycles need to start .05 away from previous one, so ......
If first cycle starts at Z.1 than second cycle must start at Z.15 and third cycle must start at Z.2
All cycles use same feed rate that does not need to be repeated on every pass.
As it stands in Fusion, pitch shift is only 0.0166 between each cycle, effectively cross threading and destroying entire thread.
Existing bugs are nuisance but produce usable threading cycles, this new bug does not.
I wanna mention few things again, we do NOT use constant surface speed in turning threads, box is checked by default in tool selection and also appears in operation definition tab.
If constant surface speed is used it hinders process by fast pace speed change as tool loops between passes, this prolongs process as encoder waits for spindle speed adjustment before each pass can start.
Default mode should be feed per revolution (G99) and strait RPM (G97), other options should not appear in this process.
Output example:
(20 PITCH THREADS, 3 STARTS)
(cycle #1)
T0101
G97 S500 M03
G0 G54 G99 X1.2 Z.1
G92 X??? Z-??? F.15
--------------
(cycle #2)
G0 X1.2 Z.15
G92 X??? Z-???
--------------
(cycle #3)
G0 X1.2 Z.2
G92 X??? Z-???
--------------
