I’m a bit stumped, and am looking for advice. I have an extremely old (Circa 2015) Craftbot Plus. It’s hardly any parts of the original unit, kept alive with custom parts out of just spite. I use cura as my slicer, and it works fine for my needs. Recently, my kids have wanted to print custom keycaps. This is a difficult FDM print to begin with, and my old hardware isn’t doing me any favors; it might be impossible. That being said, my prints turn out good, except for the tiny details in the actual stem. The picture is attached of various settings; I’ve tried a ton of stuff. I can share a cura profile, but the gist is I’m printing in PLA and have experimented with 195-210 degrees, .1mm layer height, line widths between .175-.2mm, various speeds, minimum speed and minimum layer duration, I’ve disabled ironing, and I’ve played with retraction. I’m kind of stumped, and am wondering if anyone has things I should try.

  • elDalvini@discuss.tchncs.deEnglish
    6·
    8 days ago

    It’s a bit hard to tell from a picture, but it looks like the stem doesn’t cool down enough during the print. I would try setting a minimum layer time with a high minimum speed and the “lift head” option enabled. That way, the printer has to pause after each layer and actually move the print head away from the part, letting it cool down before the next layer.

    • surfrock66@lemmy.worldOPEnglish
      2·
      8 days ago

      I have a combination of 3 settings set to do that, but I don’t think it’s working? Minimum layer time, minimum speed, and “lift head” which I thought would make the print for that layer finish and then the head would move out of the way for cooling.

  • ButteredWaffle_@reddthat.comEnglish
    4·
    8 days ago

    Hiya, my 2 cents. If you have a well tuned machine (which i assume you do):

    • Extrusion widths that are up to 50% larger than your nozzle diameter are beneficial, because the brim of your nozzle flattens the material against the lower layer
    • Printing many keycaps at once can help the stem cool completely between layers, if heat is a problem
    • Have you tuned pressure advance after swapping nozzles?
    • IMALlama@lemmy.worldEnglish
      2·
      8 days ago

      Extrusion widths that are up to 50% larger than your nozzle diameter are beneficial, because the brim of your nozzle flattens the material against the lower layer

      It always amused me that some slicers that allow for percentage based extrusion widths use layer height, and not nozzle diameter when applying that value…

    • surfrock66@lemmy.worldOPEnglish
      1·
      8 days ago

      I’ve tweaked the line width a lot, going down to .175 but not lower. It didn’t seem to make a difference. I did try to add another junk model next to the caps just to offset the heat; it unfortunately didn’t help. Which settings are you looking at with pressure advance; the main thing I have been touching is flow rate.

  • iocase@lemmy.zipEnglish
    3·
    8 days ago

    Could it be your hot end dwelling over top of this section like a helicopter parent? My experience trying to print FDM minis for DnD (didn’t and still down own a resin printer) was small layer heights and lots of detail = lots of indirect heating that causes drooping, smearing, warping and lots of other fun stuff… i actually had better experience using a coarser layer height even if the final mini didn’t look as fine detailed. At least it didn’t look fucked up.

    I don’t use Cura but my instinct would be trying a coarser layer height to see what happens. In prusa you can set a dynamic layer height depending on part geometry. Straight walled simple parts print really fast while it slows down and thins out layers around detailed areas. You can of course tweak the output yourself so you aren’t forced to use the dynamic z layer’s guess on where it needs to go thin.

    • surfrock66@lemmy.worldOPEnglish
      2·
      8 days ago

      I have settings that I thought would mitigate that, but I don’t think it’s working right? I was going for “print the layer at normal speed, then go off to the corner for a while and wait” but I don’t think that’s working; it was minimum speed, minimum layer time, and lift head.

      • iocase@lemmy.zipEnglish
        2·
        8 days ago

        Well if you figure out a solution make sure to edit your post to let us all know!

  • neoinvin@lemmy.zipEnglish
    2·
    8 days ago

    i was printing a fairly detailed blank for a mold, and printing it in the intuitive way, largest surface on the bed, left the finer details a mess. so what i tried was reorienting the object so that it was upright instead. if orientation isn’t something you’ve played with i’d give it a try, just have to make sure its properly supported.

  • paf@jlai.luEnglish
    2·
    8 days ago

    I would try a 0.4 nozzle with 0.08 layer height or 0.12 (no need of 0.2 nozzle for those layer height) with standard layer width. Also would try to print a couple in same time to let more time for filament to cool down

    • surfrock66@lemmy.worldOPEnglish
      2·
      8 days ago

      I can try when I swap the hot end back out; I had that thought and was going to print a silly model in the same print just to have more stuff to do each layer.

  • motsu@lemmy.worldEnglish
    2·
    8 days ago

    Do you have minimum layer times set? Seems like the filament doesn’t have enough time to cool. Try setting a minimum layer time of 15 or 20 seconds with your part cooling fan at 100%

    • surfrock66@lemmy.worldOPEnglish
      1·
      8 days ago

      I do, but I feel like it’s not getting respected? It’s a combination of 3 settings; minimum layer time, minimum speed, and “lift head” which I thought would make the print for that layer finish and then the head would move out of the way for cooling.

  • papalonian@lemmy.worldEnglish
    2·
    8 days ago

    Have you adjusted your flow rate? Slicers are usually pretty close to spot on for 0.4mm nozzles but in my experience going up or down in nozzle size usually results in having to change the flow % pretty significantly. In addition to what others have said about minimum layer time / heating the parts up too much, I think you may be over-extruding as well.

    The test I like for testing flow is to print a handful of cubes ~15 layers tall, with 2 bottom layers, 3 infill layers, and 10 top layers. Print each one at a different flow rate (in cura you can change settings per part to print them all at once) and look at the top layer when it’s done. You don’t want any bulging from between print lines (over-extruding) or any gaps in between them (under-extruding).