Is anyone using TinyG on a CNC lathe? Looking around the internet, I really didn't find a functioning example, everyone seems to be using them on CNC routers and mills. I saw someone posted here about hooking one up to a Spectralight lathe but there was no follow up to it.
TinyG and a lathe?
Don't see muh in that domain, but this item did appear today over at Chilipeppr
https://groups.google.com/forum/#!msg/chilipeppr/pF4cS45-4Ps/P8kBIy-ECQAJ
Yes, that is my post over there. I was hoping to hear a success story since I couldn't find one on youtube. lol
I figured it might be you.
I have not seen much about the CAD/CAM front end for lathe operation, or how the required motion might be mapped to X-Y-Z-A.
There is also a mindset issue here - when one says lathe, I think of parts that are cut from a continuously rotating piece of stock, symmetrical about the spinning axis.
Or is your goal to make the lathe axis the A axis and to create objects that are asymmetrical about the rotational axis.
I don't see why tinyG could not move the motors, assuming that the Gcode made sense.
Let us know what you find
My plan is to keep it simple and make the spindle the Z axis and the cross slide the X axis. I tried to air cut a simple cylinder shape this morning and I really thought it was going to work until it came to the edge of the cylinder. It was at that point that I was able to understand what the "I" codes and the "K" codes in the Gcode did! LOL. I should have Googled those ahead of time I guess! I'm not sure why the post processor added those since the tool path in Fusion's CAM looked correct. It made a little circular flourish at the corner which would have left me with a cove-shaped corner if I had material chucked up instead of the sharp corner I drew.
I need to work on the carriage slide of this lathe also, it's new and a little tight so it stalls the Z motor often. I have the motor removed and laying on the bench while I learn the programming.
I and J are arc codes coordinates.
I believe you can tell the post processor to generate only linear (G1) commands
OK, so in the "fanuc turning.cps-Generic FANUC Turning" post processor I was using in Fusion 360, line 35 reads "allowedCircularPlanes = undefined; // allow any circular motion". I switched "undefined" to "0" and it gave me a Gcode with no G2/G3 codes. I already had smoothing turned off and make sharp corners turned on. Haven't tested it yet though.
I had a chance to run it with the changes. Just cutting air, it moves like I expected it to now, no blue swirly tool paths in the corners so that looks much better I think. Almost ready to try making something but I would swear that it's moving the cross slide over the diameter of the part instead of the radius. I had to leave for work so I'll have to check it out later.
Thanks for the help!
OK, it really was moving the cross slide over by the diameter of the part instead of the radius. I didn't find an option to switch it over to radius so instead I changed the setting for the X axis to .1" per revolution instead of the .050" per rev that it really is. Seems to work fine and as a bonus, the DRO for the X axis in Chilipeppr still reads out the diameter for me. I even was able to make something with it today!
Chess pawn
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