"Infill before walls" doesn't seem to work...

[Rublie14 0]

Hello everyone,

 

I've just started 3D-printing a couple of weeks back and haven't had any trouble with Cura yet. Today, however, I wanted to print a pentagonic slinky which I designed myself in Fusion 360. While printing it for the first time however whenever my Anet A6 went around a "corner" of the pentagon, it sort of cut the corner because the filament didn't have any place to bind to (because it is of course printing in the air in order to be able to create the gap in the slinky (see photo)). In order to fix this I thought it would be a good idea to print the infill before the wall perimeters so that the walls had something more solid to be formed around (I know the print won't be 100% perfect as it is printing mid-air, but I just want a functional, somewhat cool-looking slinky ;-D). When I tried to tick the box for the "Infill before walls" option, though, nothing changed when I looked at it in the layer preview...

 

So my two main questions are:

1. How could I make it so that the infill is in fact printed before the walls?
2. Do you have any other suggestions to printing the slinky in a better way?

 

Thank you in advance!

 

 

Oh and here is the project file:

Pentagonic 80r Twisted Slinky.3mf

[Rublie14 0]

Can anyone help me?

[gr5 2,239]

Make sure "travel optimization" is turned off.  I think when this is on it will ignore "infill before walls".  I could be wrong.  But it won't help your print much.  You have severe overhangs.  You need some kind of support.  You can design support columns into the design of the print or if you have a printer that does two filaments you could use dissolvable support.

 

This is an extremely hard print for a 3d printer without dissolvable support.

[Rublie14 0]

Ok thank you! I will try that. The only problem with adding support in my case is that it would be almost inpossible to remove afterwards if its not dissolvable like you said (and I don’t own a dual extruder printer unfortunately).

 

Apart from that I know this print is hard, I’ve seen other printers print similar slinky designs without needing support (like on the make anything youtube channel).

 

But yeah I will try your suggestion, and if it doesn’t help my printer might just not be able to print this design...

 

Thanks!

[geert_2 558]

If you could somehow redesign the model so that there are no steep overhangs, it could work. Make smooth transistions, and no overhangs larger than 45° (from vertical). Might be worth trying?

 

[Rublie14 0]

@geert_2 Thanks for your answer! Yeah normally I would indeed do that but in this case I couldn't because that's the way this slinky works... You need the steep overhangs because otherwise the spring couldn't be created.

[geert_2 558]

2 minutes ago, Rublie14 said:

@geert_2 Thanks for your answer! Yeah normally I would indeed do that but in this case I couldn't because that's the way this slinky works... You need the steep overhangs because otherwise the spring couldn't be created.

Indeed, I forgot that...

 

Would there be a possibility to connect upper structures to lower structures via a thin single wall, which you can easily cut away later? Similar to this concept of a spring? Here the blue is the desired spring, and the pink supports would be cut away after printing. In this way the overhangs are less steep. If you would print this with a thick shell it might work?

 

(This is a picture I made some time ago for someone else who wanted to print a spring.)

 

 

[Rublie14 0]

@geert_2 Aah yeah that might be a smart idea. I'll try that if the way I sliced the spring now doesn't work (I managed to make the printer print the infill before the walls). The print is very long though so I can't start it until tomorrow morning if not later... If that doen't help with the corner-cutting I'll definitely try your clever solution! I'll update you when I have progressed.

 

Thank you for your awesome input by the way! It's so cool that random people you don't know help you!