Very tiny circles using G2 look fantastic.



  • I have installed a Duet/Ethernet onto a Rostock Max V3 with an SE300 hotend and I'm trying to print a NASA Saturn V S-IC F-1 combustion chamber by faithfully printing the 356 lower tubes and 178 upper tubes using G2 circles over and over and over and over and over.

    This part has 226,000 G2 commands in it.

    I'm literally amazed that I can print a 1mm diameter circle using a 0.5mm diameter nozzle and it looks great.

    I <almost> can't see the stepper motors turn as it's printing a circle.

    And the extruder also seems to not be moving.

    It's very impressive that the Duet can handle such teensy-tiny movements on a delta printer.

    Thanks for all your work.

    Outside of expansion bell
    Top layer of expansion bell
    Back wall showing small artifact at the layer change



  • Nice!

    Ian



  • Wow! Fantastic.



  • What slicer did you use to get arc moves?



  • @oliof I tried Simplify and Cura and they all made a real mess, so I wrote a slicer in C to generate just the patterns I need for this combustion chamber.

    I <think> Simplify could have been tamed, but I couldn't get it to generate every circle exactly the same for every layer so there were visual disturbances.

    It's just at the resolution limit for slicers I think. (Hypothesis only)



  • @oliof If you're interested in playing around with slicing, the model is in OnShape under S-IC F-1 Thrust Chamber



  • @alankilian writing your custom slicer is awesome! I know KISS is growing support for G2 moves, but I don't think the required STEP/IGES input support is there yet. So I wondered if some slicers would approximate curves from STLs and then convert to G2 moves ....



  • @oliof I guess I shouldn't call it a "slicer".

    It just interpolates a spline curve every 0.2mm, calculates a radius, rotates the center and edge points and generates 356 G2 codes to make circles.

    Another program generates tubes that turn into squashed tubes (two lines and two half-circles at the ends) as the combustion chamber moves through the throat of the engine.

    So it's really a G1 and G2 creator program. 🙂



  • Cool test! Great results! Thanks for doing that. I had actually been meaning to test this out, because I also noticed S3D's complete inablity to generate sensible gcode. Arbitrarily reducing resolution in places, while generating literal E0.0000 commands...

    We need a new slicer that takes a solid model (STEP, IGES) and slices into curves where possible, and takes into account user-defined resolution settings.



  • @bot said in Very tiny circles using G2 look fantastic.:

    Cool test! Great results! Thanks for doing that. I had actually been meaning to test this out, because I also noticed S3D's complete inablity to generate sensible gcode. Arbitrarily reducing resolution in places, while generating literal E0.0000 commands...

    We need a new slicer that takes a solid model (STEP, IGES) and slices into curves where possible, and takes into account user-defined resolution settings.

    KISS will be the first I think it already has the support for G2/G3 arcs and is going to get a method of loading IGES/STEP Files directly!


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