Straight out of WinCNC:
G12.1- (option)Converts C axis degrees and X axis movement to work like
a milling machine. Program X-Y axis and the control converts all the
commands to degrees automatically. X and Y are programmed in radius
values and zero is at the center of the part, like a milling machine.
Tool nose rad comp is also needed to use G12.1 correctly. Thinking
about the direction for G2/G3 and G41/G42 is backwards! You have to
imagine you are back behind the guide bushing looking to the cutter.
If you can't do this, then just do everything opposite!
There are some new options while calling G12.1. We used to have to
change parameters to use G12.1 #1125 Mill_AX and #1126 MillC , now
we can set these while calling G12.1 . See also G16 below.
G12.1 (no arguments uses C commands same as G12.1 D1 E=C)
G12.1 D0 E=C
D0 -You can use "C" or "Y" as the virtual axis while in G12.1
The manual suggests using "D1" to use "C" but I don't agree.
If in G17 X-Y plane, then I suggest you use "D0" to use Y".
Your choice, it makes no difference which you use! If D is
not on the G12.1 line then "C" is default.
Always have "D" first on the G12.1 line!
E=C -This will set the axis number of the system to use as the
polar axis. This depends if you are using the gang plate in
$1 or the U121B option in $2 or $3. Setting E=C will set the
proper axis automatically. If you don't use E=C on the line then
$1 C axis is default. For safety, always use E=C
(MILL A .3 SQUARE WITH .02R CORNERS)
T1100(Live face mill/.25" cutter /1/2"bar)
G98M59S3=1200 (GSE1110 is reverse rotation)
M132(Y axis mirror image off) (if not T11-13 then M132 not needed)
G12.1 D0 E=C
G1Y-.15,R.02F8.(or use G2)
M131(Y axis mirror image on) (if not T11-13 then M132 not needed)
G13.1- reverses G12.1 by setting control of the C axis back to C and H
G16- Plane select Y-Z cylindrical machining. To use this plane you need the
option of G12.1 milling interpolation. G16 is used to convert polar
C axis degrees to linear Y when machining "J" slots or cylindrical
cams. Most of these part prints are dimensioned with linear and radial
values, not degrees. Also the prints usually show the part cut and
spread flat. Radii are hard to program and adjust without G16 and tool
nose radius comp. G41-G42. Programming would be linear "Z Y".
The polar "C" axis is converted to a linear "Y" axis. Another use of G16
is to chamfer a cross hole equaly all the way around the hole.
C= Position of X axis to calculate from if the actual cutting
position is different. This is in radial value. C.15 = X.3
(MILL A J SLOT Sample program not tested yet but should work)
T900(.125" cutter / 1/2"bar/ to cut .156 slot)
(M132 is needed to swap Y mirror image if using T1100-T1300)
X.3(to depth of J slot)
G12.1 D0 E=C
G1Z.1,R.02(or use G2)
(M131 is needed to swap Y mirror image back if using T1100-T1300)
G17- Plane select X-Y
G18- Plane select X-Z normally used. G18 is when power on.
G19- Plane select Y-Z