G43.4 on Integrex i100S Sub Spindle

We have several Mazak Integrex i100S mill-turns. By some stroke of luck I've ended up being our expert programmer and post writer. Also, I'm not an expert.

I'm trying to use G43.4 for 5-axis milling on the sub spindle. However, it seems that the machine doesn't like that.

Regardless of whether or not I have head 1 or head 2 selected for milling mode (M200 and M300, respectively) any C-address will rotate the main spindle. That's fine. I can just configure the postprocessor to use U-addresses to rotate the sub spindle. That works... However, as soon as I have G43.4 active, it looks like the U addresses are suddenly treated as X-axis incremental moves. It also doesn't like U and B on the same line. Weird stuff ensues. Lots of soft limits.

I have 3 questions:
1. Is it possible/recommended to do 5-axis machining on the sub spindle?

If the answer to 1 is yes...
2. Is my failure a program issue or a parameter issue?

Slightly related question:
3. What's the best way to deal with the fact that Z+ is into the sub spindle? You'll see that I have been using G68.2 to program with Z+ being facing away from the face of the sub spindle. Is that right, or is that a lame workaround?


Sample 4-axis surfacing code:
------------------------------------------------------------
( MAZAK I100S SMOOTHX )

G40 G17 G90 G49 G20

N10
(*******************************************)
( NX_CAM_TOOL_NAME: GP_T22 )
( OPERATION: 4AX_SEMI )
(*******************************************)
G109 L1 (UPPER TURRET SELECT)
M902 (HD 2 SELECT)
M300 (U AXIS CONNECT - MILLING MODE)
G00 G17 G90 G94 G97
G40 G49 G80 G67 G69
G91 G30 P3 X0.0
G91 G30 P3 Z0.0
G91 G30 P3 Y0.0
M108 (B AXIS UNCLAMP)
G90 G53 G00 B0.0
T22 M06
G65 P8005 T22 ( CHECK TOOL OFFSETS )
G65 P8009 ( OVERLOAD SETTINGS )
G17 G97 G90 G54.1 P1
G68.2 X0.0 Y0.0 Z0.0 I0.0 J180. K0.0
M108 (B AXIS UNCLAMP)
M212 M312 (C AXIS UNCLAMP)
G53.1
B170. C170.2798
S7500 M03
G43.4
M131
M103
M08
G94 G90 X.5162 Y-.07 Z2.4194 H22
(OVERLOAD DETECTION ON)
M871 A107 (SET X OVERLOAD PERCENT)
M871 A204 (SET Y OVERLOAD PERCENT)
M871 A304 (SET Z OVERLOAD PERCENT)
M871 A803 (SET MILLING SPINDLE OVERLOAD PERCENT)
M875 (SPINDLE AND FEED STOP AT OVERLOAD TRIP)
Z.017
G01 Z-.0162 F60.
X.5159 Y-.0761 Z-.0399
X.5152 Y-.0892 Z-.0605
X.5142 Y-.108 Z-.076
X.5131 Y-.1306 Z-.0849
X.5118 Y-.155 Z-.0864
X.5219 Y-.1537 Z-.0811 C166.2336
X.532 Y-.1516 Z-.0754 C162.1564
X.5418 Y-.1488 Z-.0697 C158.1068
X.5512 Y-.1452 Z-.0638 C154.0802
X.5604 Y-.1409 Z-.0577 C150.0566
X.5692 Y-.136 Z-.0515 C146.021
X.5777 Y-.1303 Z-.0452 C141.9691
X.5857 Y-.124 Z-.039 C137.9472
X.5931 Y-.1172 Z-.0327 C133.9398
------------------------------------------------------------

This works... Other than the fact that it rotates the main spindle C-axis instead of the sub spindle.

I have the programming manual and the M-code and parameter manual, but I haven't found them to be very helpful for the sub spindle.

Anyways, I'll try to call Mazak applications tomorrow, but I figured some of the smart people here might be able to help first.

You have to be careful using tilted plane G68.2. Integrex does not support G68.2 on the sub-spindle. I have contacted Mazak engineers, they told me the same thing.

If you have the EIA manual, you can see below mentioned (in the Notes section):
"Inclined-plane machining is not available if the C-axis control of the turning spindle No. 2 is
concerned."