How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
hey everyone,
I am creating quite a big marble machine, and one module of this machine will be hyperbolic funnel (a.k.a. vortex funnel or wishing well).
Problem is, I can't get it to print nicely, to have a smooth top surface for the marble to roll nicely. Here I have printed a second test model, of only the top 20% of the model to test the top surface. Problem is that the surface gets really grainy, and in some spots, I can even insert tweezers in, because there are little holes present. So obviously marble doesn't run smoothly.
I tried slicing this in two different ways, none worked. Currently, I have it at default 0.2 Prusa quality MK3 preset, with quality (slower slicing) options enabled. I also manually edited layers for the top of the hyperbolic curve, to lowest values, so that I can get a maximum resolution for the curve.
this is how I modeled supports underneath the curve. For the first test, I had it differently, supports were solid, and print still turned out bad. So I don't think the problem is in supports.
I don't know what else can I try in the slicing options, or in the modeling of the supports.
I could try to print it sideways, but then I have a whole another set of problems with overhangs and I would probably need to redesign the model, to make it into hexagon shape like the first image of the coin gravity well.
Maybe that is going to be the only option or am i missing something in the prusa slicer options that would make it printable as it is? 🙂
Best Answer by bizilux:
you are right, I didn't even think 0.07x10 is not that much 😀 I bumped it to 11 top layers now but it seems to be working fine at 10. Well, kids won't be dropping marbles on it, its automated machine with motor, but yeah marbles will be "dropping" on it for a long time. So I'll see if I need more top layers or not. This machine is more meant for grown-up kids like myself 😀
right now I redesigned the funnel a bit. Before I had hyperbolic shape, but it did not give me the desired effect of those coin gravity wells. I found cross section sketch of the gravity well and now I remodeled it because it turns out they are not hyperbolic lol. Basically, it's quite a bit less flat at the top now. Marbles were just rolling around the top edge until they lost enough momentum to just drop in the middle.
Now I am printing final test piece(9th already) because on Friday I'm going on two weeks vacation and I'm also gonna run out of filament so I will need to buy more 🙂 when I come back, I will print the whole piece.
25 hour print time, not including the base for the module and also need to do the path that will send marbles into the funnel... ajajaj 🙂 Not the best scenario when trying to sell models, but okay, hopefully it will look and work amazingly once its printed
This is what im trying to do if anyone is interested in these sort of things 🙂 (skip to 2:53 for this particular piece)
Thanks, everyone for your amazing help! turns out I just needed to crank up top layers way up!
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
Looks like you are fighting several issues, one being a material flow problem: the material should never be "gritty" like your image is showing. Second being it isn't reasonable to print large unsupported objects and expect any characteristic accuracy for rolling balls.
Can you post the STL (zip first).
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
@tim-m30
thanks for your input!
the thing is, that grittiness is only present on this model at those overhangs, it must be some slicing thing? I think there are not enough top perimeters, but I don't know how to force Prusa slicer to make more, because these are technically not top perimeters, neither are normal perimeters.
this is how the model looks like: I was hoping for it to print in one piece.
Vortex Funnel I attached STL file for this model (the top 20% that is relevant for this problem). I don't think to change anything with supports will help, because I did that for the first print, it had more supports and it still ended up gritty with even bigger holes? :S
I can add more supports but I don't know if that will fix the problem
And this is how the whole marble machine looks like so far 🙂 (shameless plug, WIP 🙂 ) and god is it starting to slow down my Fusion 360... :/
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
I think your best bet to print that would be to slice it in half along the diameter of the circle and print it standing vertically as two semicircles you glue together. That way the layer lines are going to be perpendicular to the rolling surface.
But regardless you're still going to have to do some postprocessing to smooth the surface a bit; maybe add some extra perimeters so you have more material to work with during that step.
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
Sanding primer FTW!!!
Actually - was looking at a similar funnel and variable layers are a natural for the part. Get as small as possible on the flat sections, that way any fairing needed is also reduced.
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
how about printing it as a thicker solid, so the top is 5 or more layers thick. you will still have some layer stepping but it will all be supported
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
sadly my account is new, so my long reply with pictures and stl file is in moderation...
I can only write like one paragraph, so here is STL link for the time being: bit.ly /2mk6SNC
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
I have just approved your post,
Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
sadly my account is new, so my long reply with pictures and stl file is in moderation...
I can only write like one paragraph, so here is STL link for the time being: bit.ly /2mk6SNC
Okay, my reply is approved now, so check post #3 for proper link, etc... 🙂
how about printing it as a thicker solid, so the top is 5 or more layers thick. you will still have some layer stepping but it will all be supported
It is already 4mm thick, and using a variable layer height of 0.05mm, it should be plenty of layers, but Prusa slicer doesn't slice it that way I guess.
also: sanding is not an option. Because i intend to sell these models, and if i start sanding this part, then i will need to sand all other parts also to match the look. So i can only slice this model if needed somewhere where marbles don't roll, so that gluing together produces no major seams that need to be sanded.
Thank you joan, could you maybe make it so rest of my replies dont go to moderation also? 🙂
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
Here's one approach that might help ...
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
Here's one approach that might help ...
yes, that would probably work out better, but you used proper supports, and if you checked the image of a full model that I posted above, it would be too much supports used, and too much time wasted on them.
I am trying a prototype redesign of the funnel and will report back on how the top layer looks.
This redesign has solid 45 degree overhangs, so in terms of that, it should print fine, no bridging involved.
I am only printing the top 20% again
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
The support under the funnel probably is not the root cause of the gravelly surface texture. I've not seen PLA do that, and PETG only when printed too cool.
But the new design is bound to have exactly the same issue since the rolling surface of the funnel is the same. Setting top layer count and ensuring perimeter thickness are two settings that you can change to force the slice to build a certain "wall" thickness. This can help strength and helps keep the infill from showing through.
The problem with the "bottom" of the funnel - where you have radial beams to support the underside - is the perimeters there are long, unsupported, and simply can't print with current technology. You can't start and end an extrusion mid-air. The only way to deal with building the part is to start with either infill or supports. Since the entire part is essentially a sealed canister, infill is all you have access to -- unless you do some imagineering with forced supports and plan ahead to leave the material inside the can. But infill doesn't need to be 20% dense, either; you can minimize the infill to make it act like support trimming density and print times. Again, just some planning.
But back to the issue you raised: a smooth top surface. Let us know how this latest print turns out.
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
Here's shot of the underside showing bridging overhangs that are arcs. These will fail, period. When extruding, one end might connect to one of the beams, but then as the extruder draws the arc the plastic is only connected to that beam, so stretches straight between the nozzle and last attachment point. The first few inner rings might form properly, sort of, but the out rings will simply fail. You can't print an arc in mid-air (well, you can, but it won't look like an arc when the mess is collected on the nozzle).
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
i would try tim's approach and remove the 6 intrinsic supports you modeled in .
another approach would be add at least 6 more intrinsic supports 1.8 mm wide ( 4 extrusion widths) and make the lower side of all the supports slope up at 45deg from the out side of the part to allow them to print with out support
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
so yeh, the test was a fail or success, depending on if you are a glass half full or half empty type of a guy 😀
It is a bit better, but I can still stick tweezers in some places.
The part has infill support of 15% so that shouldn't be a problem. Problem is too thin top layers.
So yeh, as I thought at the start... support isn't really a problem I think.
I will test perimeter setting, this picture is comparing one layer on default 2 vs 5 perimeters:
5 perimeters:
off to printing now, and I have cut off even more from the bottom of the model now, I'm only printing the top 10%, pointless to wait for 5 hours when 2 hours are enough 🙂
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
what are your top and bottom layers set to?
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
what are your top and bottom layers set to?
That is what im testing today
Bottom layer is always 4.
- test: 5 perimeters, 5 top layers (it looked so so..)
- test: 8 perimeters, 5 top layers (better looking and working, but still cloudy/grainy)
- test: 9 perimeters, 9 top layers (still printing, but it looks like cranking those top layers way high is going to work)
I am hoping this last test works, and then i can test again with 2 perimiters and 9 top layers to see if top layers is the king here
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
Don't forget to have the "Ensure vertical shell thickness" turned on:
This is found in Print Settings/Layers and perimeters. Yellow setting so you need to be in at least Advanced mode to change.
The "Extra perimeters if needed" setting right above might also help if it is off (red setting so you need to be in Expert mode to change).
For your final print, you may want to print this funnel tower in two pieces, the top funnel part and then the bottom cylinder part. That way you can get good supports for the funnel without wasting plastic in the main volume of the cylindrical base (and allows retrieving marbles that may fall off the track inside the funnel). I'd put notches in the underside of the top funnel part and matching tabs sticking up in the bottom cylinder part to help positively attache the two pieces. Probably don't need to go as far as non-symmetric notches/tabs to enforce a rotational orientation though.
Another option (though would take more 3D modeling skills than I have) is to build up the supports inside the cylindrical base looking like architectural vaulted ceilings, avoiding going over 45°-50° from vertical so you don't have to do supports for your supports. 😉
See my (limited) designs on:
Printables - https://www.printables.com/@Sembazuru
Thingiverse - https://www.thingiverse.com/Sembazuru/designs
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
everything except for crossing perimeters is enabled already 🙂 I also thought about making tree supports inside, but I'm not that good with fusion 360 yet either 🙂
and i want to avoid printing in multiple pieces as much as possible. this whole machine will be in many pieces as it is already, mainly because of option for 2 different colors... so trying my best to keep the number of parts down.
okay so results of the latest test: 9 perimeters, 9 top layers
A bit grainy looking, but the top surface is smooth. the filament is a bit transparent that's why it looks like that.
I have downloaded Prusa slicer 2.1, and just like they knew that i needed height modifier. So now I'm trying height modifier with 100% infill and then I will compare these two results
RE: How do i print Hyperbolic Funnel? (VERY high overhang angle with supports)
Extra perimeters won't help the issue you are having - the issue is top layer thickness is allowing print through. With 0.2 layers, only 4 layers is pretty thin. Also, gyroid infill for a part with cylindrical solid infill is going to cause problems because it is essentially a linear structure at certian angles. I'd use the hex pattern infill to ensure proper support at all angles.
btw: The height modifier wasn't working last time I tried it. Good luck with that.