I am running into seemingly random catastrophic errors in 4 axis toolpaths. I'm not sure if it's the toopath as generated or if the post processor is messing with it but I've attached two pictures of the latest example. At first, I thought it was failing to go to safe z between toolpaths but this one happened in the middle of a revolution roughing pass. It was set for pocketing and it looks ok in the simulator. In the simulator it ends at about A=540 degrees. In the G Code it does a rogue roll near the end of the toolpath to -140 degrees without raising the bit so it rips right through the piece as shown in the picture. I paused it, raised the bit and continued and the rest of the toolpath finished properly. Naturally this is a show-stopper so I'm hoping someone has a clue what could cause this. I have the rhino file and the full GCode I could send but it's pretty big so I would probably need to email it.
My post processor is configured as follows...
//MadCAM_POST_PROCESSOR
*VERSION*
4.2_100101
*FILE_NAME*
MachBot_4_axis
*FILE_EXTENSION*
tap
*FILE_DEST*
c:\postfiles\
*FILTER*
0.001
*OUTPUT_WIDTH*
4
*OUTPUT_DECIMALS*
3
*SCALE_1*
1
*SCALE_2*
1
*SCALE_3*
1
*SCALE_4*
1
*SCALE_5*
1
*AXIS_1_CHAR*
X
*AXIS_2_CHAR*
Y
*AXIS_3_CHAR*
Z
*AXIS_4_CHAR*
A
*AXIS_5_CHAR*
B
*CUTTER_REFERENCE*
TIP
*RAPID_FEED*
90
*END_SECTION*
*TOOLCHANGE_TIME*
0.5
*END_SECTION*
*TOOLPATH_OUTPUT*
TRANSFORM
*RAPID*
G01"x""y""z""a" F90
*END_SECTION*
*RAPID_APPROACH*
G01"x""y""z""a" F90
*END_SECTION*
*RAPID_RETRACT*
G01"x""y""z""a" F90
*END_SECTION*
*APPROACH*
G01"x""y""z""a" F"feedz"
*END_SECTION*
*FIRST_CUT*
G01"x""y""z""a" F"feed"
*END_SECTION*
*CUT*
G01"x""y""z""a"
*END_SECTION*
*TOOL_CHANGE*
(Change to Tool "toolname")
G01"zhome"
M6 T0"toolnr" G43 H"toolnr"
M03 S"speed"
*END_SECTION*
*TOOLPATH_CHANGE*
(New Toolpath)
G01"zhome"
*END_SECTION*
*TOOL_STOP*
M5 M9
*END_SECTION*
*PROGRAM_START*
(MachBot_4_Axis Post)
(Rhino Document - "documentname")
(Output Date - "datetime")
*END_SECTION*
*PROGRAM_END*
M06 T00 G49
M30
*END_SECTION*
*LINE_START_NUMBER*
1