TinyG and a lathe?

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Viewing 9 posts - 1 through 9 (of 9 total)
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  • July 24, 2017 at 7:54 pm #10478
    bracketracer
    Member

    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.

    July 24, 2017 at 8:18 pm #10479
    cmcgrath5035
    Moderator

    Don’t see muh in that domain, but this item did appear today over at Chilipeppr

    July 24, 2017 at 9:40 pm #10480
    bracketracer
    Member

    Yes, that is my post over there. I was hoping to hear a success story since I couldn’t find one on youtube. lol

    July 25, 2017 at 8:49 am #10483
    cmcgrath5035
    Moderator

    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

    July 25, 2017 at 5:26 pm #10485
    bracketracer
    Member

    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.

    July 26, 2017 at 3:16 pm #10492
    cmcgrath5035
    Moderator

    I and J are arc codes coordinates.
    I believe you can tell the post processor to generate only linear (G1) commands

    July 27, 2017 at 4:15 am #10493
    bracketracer
    Member

    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.

    July 27, 2017 at 2:01 pm #10495
    bracketracer
    Member

    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!

    July 29, 2017 at 11:34 pm #10501
    bracketracer
    Member

    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

    • This reply was modified 7 years, 5 months ago by bracketracer. Reason: photo link did not work
    • This reply was modified 7 years, 5 months ago by bracketracer.
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