Comment on Issues with model, slicing or printer settings and/or calibration?
Bluewing@lemmy.world 4 days ago
It’s possible your original Blender design had an issue. Blender is not always kind to 3D printers.
The first thing I would tell you is to stop using cubic infill, it is evil. It never always causes me failed prints, especially larger prints. Nozzles often tend to drag across the previous layers and can easily cause failed prints. I can even hear the nozzle hitting the infill as I print. I often recommend gyroid as a good all around infill pattern.
How to think about this design problem.
I look at it and I wonder, does the rolling pin need to be supported full length? A wooden rolling pin is ridged and only needs minimal support on the ends. So I might just design the cradle only at the very ends. And then design the middle to be a simple flat that connects the two end pieces. I might even skip the middle altogether and just print the ends. That saves the most material and time and still does the job perfectly.
When it comes to slicing your print, orientation matters. How you support overhangs can be tricky and often compromises must be made. While I will use the auto supports as often as I can, sometimes you just need to use paint on supports to get what you needwhere you need it. Pay attention to the top zed support gap. The defaults are never right. I always open them up more. With a .40mm nozzle, I use a .265mm gap. For a .60mm nozzle, a .365mm gap.
You might even need to print your parts at an angle. Often tipping the part at 30 to 45 degree angle can make those nasty over hangs completely printable without supports.
And this is only a good beginning. How fast you might print an overhang matters, the amount of cooling fan can affect the over hang, lots of fine details that you will learn about as you keep doing this.
Good Luck and never fear making a mistake!
cyberwolfie@lemmy.ml 4 days ago
Thanks for a very thorough answer!
I’ve had good success with previous Blender files, although this is the first time I’ve used a boolean operator to cut out anything. I usually use FreeCAD for these custom Gridfinity pieces, but the process of converting the .stl mesh to a solid part in FreeCAD seems a bit error prone (several steps involved), and I haven’t yet used booleans in FreeCAD. I could try that again.
Good to know! I use PrusaSlicer, and this grid infill is the default. The way you describe it sounds like what I experience, and I can in fact see some artifacts when I inspect it closely. Though, the sounds I hear would only start when the concave part starts, and that’s also where I see the failures. But that could possibly because there’s too much overhang over the cubic infill? Anyway, I checked out gyroid pattern, and it was pretty dense with the 15% default infill value. What type of infill % do you typically use? Seems I could get away with less here.
You mean an open container with maximum depth and width between the ends that holds the ridges? That could be a good way. They way I ended up doing it was essentially just a rectangular cut-out which worked fine and is similar to your suggestion (although I could save more material doing it your way), but feels less custom… as if that is a goal in itself. I would not like the gap by just printing the ends though, as I wouldn’t be able to squeeze anything else underneath and it would not look right to me. Wish I didn’t think like that, so I could save material, but I know myself enough that I would be annoyed every time I opened the drawer…
This I will need to read up on more. I don’t actually use supports for these Gridfinity prints (but PrusaSlicer does warn me about potential instability…). The printer handles the overhang between the grids fairly well, but I guess I didn’t think about the long lines crossing the infill. In other prints I’ve only used the auto supports. Could I ask you what slicer you use?
Thanks! I must admit I do fear it sometimes when the printer makes some weird noises…
anguo@piefed.ca 4 days ago
Gyroid infill used to be the default in PrusaSlicer, but they changed it to grid when the MK4 came out with input shaping and much higher speeds. Straight lines gain most from the increased acceleration. Gyroid will now make your printer vibrate like crazy.
This is also not cubic infill, that's another one (which I would recommend over grid for structural pieces). I actually almost always use Adaptive Cubic infill, which saves a lot of filament.
I also believe that your print would probably had turned out fine in the end, it doesn't seem like there were any catastrophic failures in your photos, despite the noise.
cyberwolfie@lemmy.ml 3 days ago
Good to know - don’t think my neighbors would be all to pleased with additional noise (and not me either).
Ah nice, it seems that the adaptive cubic will make larger pockets? Neither cubic nor adaptive cubic seems very… cubic to me, though. Why is it called this?
So far I’ve not been making any structural pieces, but that is something I will remember for when I do.
Hm, OK, maybe - I think however it would have been difficult for me to keep it going when it sounds like I am destroying the printer for every layer
anguo@piefed.ca 3 days ago
Adaptive cubic does indeed make larger pockets in areas that are far away from walls. As for the name, I myself imagine cuboid shapes standing on one corner. Prusa has a great page on different infill types: https://help.prusa3d.com/article/infill-patterns_177130.
The only advantage I can think of for grid infill (that you're using) is that it reportedly makes better flat top surfaces.
I manage a few Prusa printers at a school, and have set the default profiles to use 15% adaptive cubic infill.
I change the infill in the following cases:
I wasn't there to hear it, I might have felt the same :)