Support settings for delicate prints

[filip_saf]

I’m printing a wand blender coupler for a coleague of mine.

The CAD model image is included at the end of the post. The total height of the model is 23 mm and the widest diameter (at the outside of the fins) is 35 mm.

I’ve succesfully printed one piece but broke 7 out of 9 fins while removing supports. The fins are 8,5 mm long, 1,5 mm wide and 8 mm high. 5 of them broke when I took off the horizontal support at the base of the fins. The vertical walls of the support deformed and took the fins with them.

I’ve sliced my .STL file with Cura, but I didn’t change support settings as this is my first supported print, so I don’t really know how to set them up.

So my Z distance was 0,1 mm and X/Y distance 0,2 mm. I was thinking of changing the distances to 0,3 mm for Z and 0,5 mm for X/Y. I don’t need perfect smoothness for fins’ base surface, but since the fins take up most of that surface, I want to make it as smooth as I can with supports cause I won’t have much room for sanding it.

The second problem is the hole in the middle. It gets filled with support which I can’t catch in order to get out.

I could flip the print, so the support is not near the fins, but on the other side the height to base is 13,5mm and there is also a middle hole with sqared sides which catch the flaps on the blade shaft. This is the part that failed on the original part (the squared sides wore out) so I was trying to avoid doing anything to it, but I might have to.

Even so, I’d still like to get some help with determining support settings.

Also, I’ve had a really hard time pulling the part off the bed. I’ve left it to cool down for 1,5 hour and i barely managed to pull it off. So any tips on that as well? I couldn’t fit a spatula under the part in order to lift it, so I had to twist it with my hand, but since the contact area is so small, I might have pulled it off vertically, it would be the same. I’ve got a MK2S Prusa with PEI sheet so I don’t want to ruin it.

Maybe heating the bed for a couple of minutes would help get it off after it cools down?

[keebie81]

For the PEI bed Lulzbot recommends removing PLA prints at 45c. They have the end gcode set so the bed stays at that temp after printing. The prusa is fairly similar,maybe try their part removal temp suggestions and see if that helps any LulzBot | Taz-5-cura-profiles

For removing supports I use simplify3d which leaves a denser layer at the top. I use a dull exacto blade to get between the support and part to remove supports.

[wirlybird]

I can take a look later and if it is successful I may be able to send you the gcode to print it on the MK2.

I definitely thing you want to print it with the fins facing up.

Have you tried using the Prusa version of Slic3r?

[filip_saf]

I’ve tried Slic3r on a previous print I did, but for this I chose Cura. Don’t know why, the supports seemed neater, I have a G code in Prusas’ Slic3r edition as well.

But Cura or Slic3r, I still don’t know the good rule of the thumb for support distances settings and related settings

If you want, I can send you the .stl, although I’m not looking for a shortcut with this print, I would try different settings but I don’t have more than 1-2 hours to print daily now and it’ll be like that for another week or so, so some general help and tips for support settings would be greately beneficial.

[filip_saf]

Maybe my spatula is too thick (0,5 mm). I’ve ordered a set of painters’ knives on Amazon, but the lead time is 3 and a half weeks.

Simplify 3D seems nice, but I’m not willing to splash out 150-ish bucks for something that will be of no great benefit to me. When I get most of the ins and outs of 3D printing, I’ll think about it, but for now, Cura and Slic3r are more than enough for me.

[wirlybird]

Ok, I would print it with fins up (or to the left if you are a Jimmy Buffett fan).

That way the supports should only be under the disk. I am not in front of Slic3r so I can offer to much on setting right now but there are a few to watch for.

Feel free to send the STL. I can look later and see what traps there may be. Slic3r should do an ok job on this with supports. I am not a fan of their supports and use S3D for more complicated ones.

[wirlybird]

What material are you using?

[RCole]

I have had great results using the slic3r supports. Easy to remove and some models I’ve printed have 1mm thick parts that were supported.

If you want to do custom supports, I would suggest using MeshMixer to build the supports and then slice in slic3r.

The other thing I would try is no supports at all. I did a print with 30mm overhangs (between uprights) and it printed near perfectly - a little rough but no noticeable sag. Make sure slic3r is set to detect bridging perimeters (Print Settings >> Layers and perimeters). My Mk2 does bridging extremely well as long as there are supports at either end (like your fins would give you).

[wirlybird]

Good idea to try and bridge between the fins instead of support especially for a smaller piece.

The issue I see is that you will lose the “arc” or circular path since the filament is going to try to make a straight line from fin a to fin b with nothing to grab on to unless it started to print that layer from the hub out. This may not be an issue though but it just might look a bit different. Would be an interesting test.

[filip_saf]

I did the print upside down and it worked. I’ve gone for 0,5 mm X/Y support distance and 0,15 mm on Z distance. The roof was a bit harder to remove, but I’ll write that off the this being a small print so I didn’t have a big surface to grab.

The finish is a bit coarse, but I’ll get a hang of the settings with time, this is only my 4th ever print.

You might notice the small edge on the upper part of the model, that’s only 0,175 mm difference in radius and it printed perfectly, I was really surprised to see that to be honest.

Oh, and I started removing the print when the bed temp dropepd to almost 45 °C, it popped right off, so thanks for the tip.

[filip_saf]

I’ve managed to print the part upside down, that did the trick. I mean, the first try was also a success but the fins were just too weak so they broke when I removed the supports.

If you want, I can still send you the .STL file, just to see the difference in quality, if you’d want to print it. It takes 1h to print with settings I used in Cura (this was my 1st Cura sliced print, I wanted to try that also) and we can then compare results. Also, I’ve printed it out of PLA that comes with MK2S, I’ve only got the printer a week ago so I still don’t have anything else to print from.
blender_coupler.stl (392 KB)

[filip_saf]

Here is my print. The side with the fins feels really smooth. Every surface feels spot on, vertical walls and the horizontal floor.

The other side, where the support was, as I’ve said feels a bit coarse, you can feel the gaps between the lines, especially with your fingernails.

And the really rough edge on top of that side is the result of supports being too close and me not having proper tools. I don’t know why, but even though I’ve used X/Y distance and minimal distance to be 0,5 mm, it got really close to the print here. But there is also an option that was selected “Z overrides X/Y” or something like that, so maybe that got to do something with it.

Oh, and this was printed with 0,15 layers - 0,2 mm first layer. First layer temp. 215 °C, other layers 205 °C, bed temp. 60 °C

[wirlybird]

Looks pretty good from here.