Designing a simple photo frame. I wanted to make it so that it prints without supports. While printing, however, the back support part wobbles/vibrates with movement, and is printing terribly.

Ender 3v3 CoreXZ, PolyTerra matte black filament, using the CR-PLA Matte profile in Creality Print 7. Tried printing at slow speeds, the issue still persists.

I’ve tried making the back support with only 45 degree angles (previously it was an x diagonal), made it thicker (from 0.75mm to 1.5mm). Nothing is working. Please find the stl and 3mf here (https://www.thingiverse.com/thing:7281179).

Is this a printer issue, a model issue, or a slicer issue? Please advise.

  • WFH@lemmy.zipEnglish
    12·
    19 hours ago

    There are a few major issues with your design that we could fix to make it work.

    • your feet connect to the frame at a right angle. You’re concentrating all the forces on a single layer line that would easily fail. Spread the forces by adding a fillet between the feet and the frame
    • your vertical and free standing parts are waaaaay too thin. From empirical observation, I’d say anything free standing under 5mm thickness is guaranteed to fail. You could easily add strength by using a triangular or U-shaped cross section. Not only the part will be much more rigid and solid, but also more stable while printing. Think I-beams or U-beams vs. flat stock in construction, with the added issue of the massive anisotropy of FDM fabrication.
    • As others have said, if you absolutely want to keep it thin, print the frame separately from the feet flat on the back so the forces are perpendicular to the layers. A V-shaped groove will print without supports. 45degs will be fine, depending on your printer you might event get away with shallower angles.
    • if you want to keep it as a single part, you might consider printing it at 45 degrees from vertical. Layers would have much more surface area compared to the current flimsy ones, and you might even not need as much bulk as vertical printing. Most usual forces would be spread at 45 degrees too, which, while not ideal, would be much more solid than parallel from them.
    • nieceandtows@programming.devOPEnglish
      3·
      18 hours ago

      Thanks for the pointers. I tried 45 print, and the vertical part broke off within the first inch or so lol. Should have tried at low speeds, because until it broke, it looked pretty good. May be that filet could have made it not break off that way.

      • WFH@lemmy.zipEnglish
        2·
        10 hours ago

        Yeah the most valuable skill when designing parts is to learn how to design for the process. Print orientation should be decided in the earliest stage so as to maximize strength where it counts, reinforcements to compensate for layer lines weakness should be baked in. FDM prints behave like wood: strong across the grain, weak through the grain.

        If it wasn’t for the groove, my first advice would have been to redesign the part so it could be printed sideways.

    • nieceandtows@programming.devOPEnglish
      2·
      18 hours ago

      Could you point me to some images of the u shaped or triangular cross section? I’m having trouble visualizing it.

      • WFH@lemmy.zipEnglish
        1·
        11 hours ago

        Yeah sure.

        Something like that: Example

        The triangular cross section would be much easier on the printer.