Fusion 360 - Lathe Post ??

I'm leaning Fusion and started poking at LinuxCNC posts for the lathe. I built a 1/4" rod in Fusion and asked for a 1/4-20 threading operation. I ran this with two posts, one for LinuxCNC Turn and one for Tormach Slant Bed. The Post(s) aren't too long and came out like this:

%
(POST_LATHE)
G7                               (Lathe Diameter Mode)
G18                             (Z/X Plane)
G90                             (Absolute Distance Mode)
G20                             (Inch Units)
(G54                            Tormach - working coordinate)
(G40                            Tormach - cutter compensation OFF)
G53 G0 X0.                 (Rapid to machine X=0 : Post Option or G28)
G53 G0 Z0.                 (Rapid to machine Z=0 : Post Option or G28)
                                     (also Post Options for X only, Z only, etc)
(G30                             Tormach uses G30 rather than G53 - same unless G30.1 used to set X&Z)

(THREAD1)
T1 M6                           (Load tool #1)
(N10 T0100                  Tormach uses this for tool ????)
G54                               (Use work coordinate 54)
M7                                 (Mist coolant ON)
G97 S500 M3               (Spindle RPM Mode, Speed = 5500, Start spindle clockwise)
G95                               (Units/Revolution activated, ERROR IF NEW FEED RATE IS NOT SPECIFIED)
G90 G0 X0.65 Z0.2      (Absolute Dist Mode, Rapid move to X and Z - Safe X and Z)
G0 Z0.2123                  (Rapid move to Z - start point for thread control line)
(                                     Tormach moves X before Z)

                                      (Canned Cycle - 1/4-20 thread - looks OK)
G76 P0.05 Z-1. I-0.4 J0.016 K0.08 R2. Q29. H0. E0.04 L0
(                                    Tormach doesn't include H, E or L - maybe cuz they are zero in this case?)
                                     (Post Option for end taper L1, L2 and L3 - haven't tried)

G0 X0.65 Z0.2             (Rapid to Safe X and Z)

M9                                (coolant OFF)
M5                                (Spindel STOP)
G53 G0 X0.                  (Rapid to machine X=0)
G53 G0 Z0.                  (Rapid to machine Z=0)
(G30                             Tormach again uses G30)
M30                              (Program End)
%

My main question regards the G95 which turns on "Units per Revolution" Mode. I don't think this is needed for G76 threading and can't see why it is included. Does G95 only affect cutting moves like G1? Does it affect G2 and G3? The documentation indicates the G95 requires a new feed F declaration, but that may only show up upon a G1 move? I have not tried loading this G-code into a LinuxCNC controller yet.

What scares me is there is no reset before ending the program. There is no G94 to reset the mode to "Units per Minute". I can easily see executing an MDI "G1 Z-1 F4" and having the machine take off at 4 inches per revolution. Very exciting but undesirable.

Is anyone using the Fusion Posts for LinuxCNC lathe?

Thank you for any insight.

Hugh

Bump.

if you have a program like notepad ++ and have a post processor that is close but not quite what you are looking for you can get inside of the post processor and tweak it in to what you need. you can actually change quite a bit of stuff inside the post processor with a program like notepad ++

so to add a little more you could alter the ending block of the post processor to add the G94 to the code it spits out. if that's what you are looking for? i'm more of a mill guy but have been using fusion 360 for a while now. you can save a copy of your post to your desktop and direct fusion to use that copy to post your programs from.

it seems to be a simple enough fix if that is the only concern?

machinedude:

Thank you for the response. I've done some hacks (too crude to be called mods) to my Fusion milling post. I've heard a programming editor (java script?) will ease modifying these posts but I, like you, are just using an generic editor (Emacs).

But it's not the physical editing of the post. It's more why the G95 is there at all. I don't think the threading cycle G76 requires it. But both LinuxCNC turn and Tormach Slant Bed posts output the same thing. I'd like to know what it does here, or get confirmation that I can removed it without ill effects. I thought someone here would have this insight.

When I get time I'll have to run some tests using more that just a threading cycle. Maybe a threading and then straight turning. See what the code does about G95 and G94.

Thanks for the help.

Hugh

Strongly suggest you go on youtube, search for NYCCNC, and check out his post processor video(s).  He has one where he demonstrates Visual Studio Code and some g-code / F360 plugins used for editing post processors.

The massive win is that you can have a code file and the post processor open side-by-side, and when you select a part of the gcode, the plugin will show exactly what part of the post generated it.

Makes reverse-engineering and editing posts so much easier it's like cheating.