removing walls (aka perimeters) in specific places (printing speaker enclosures)

[DeepSOIC 0]

Hi!

After getting tired of workarounds with Slic3r/PrusaSlicer, i finally decided to try it in Cura, since i heard it's also supports modifier meshes.

 

The goal is to print a speaker enclosure, where the volume of the enclosure is filled with air-permeable infill. For that to work, i essentially must remove some walls from an otherwise normal 3d-print. So i add a modifier mesh that envelops these walls, and configure it to have no perimeters.

 

The result is the same as with Slic3r/prusa: the walls are removed, but internal walls are created instead where the the modifier mesh boundary is.

Is there any setting i'm missing, or is it just impossible, and i have to actually carefully model the whole infill volume in cad just like i had to with slic3r/prusa?

Cura 5.0.0, project attached.

CFFFP_spherical v3 Enclosure shape (Module002).3mf

[DeepSOIC 0]

here's what i want, conceptually (it's a different model that i slic3d and printed long ago)

[GregValiant 1,351]

You can kind of do it.

Right now your cutting mesh is leaving it's own cavity and since the main model has "walls" the new cavity is getting walls.

Your cavities in the main model are too deep.  They should be just deep enough to sink the speaker mounting flange.

Behind those your "cutting model" must be configured as an Infill Mesh and not a Cutting Mesh.  0 walls, 0 top, 0 btm, 0 infill.

In Mesh Fixes turn on "Remove Mesh Intersection"

After printing you will need to use a hole saw and cut the holes in the shell (Your model can have printed pilot holes as drill guides).  The inside of the shell will be as you want it.  No infill where the rest of the speaker fits.  That interior baffle - I suppose that would need to be a separate mesh.

 

This is my model to demonstrate.  You can see the gap in the infill from the cutting tool.  With the face of the pocket cut away the speaker gap will be revealed.  The round shadow under the sphere is a flat feature 1mm thick that I sink into the Cura build plate.  I put them on both models so I can precisely locate them in Cura.

[DeepSOIC 0]

hmm, nice idea, thanks! Certainly better than dremeling out the unwanted walls in the full cavity which is what i did previously. I'll try!

Edited June 8, 2022 by DeepSOIC
typo

[GregValiant 1,351]

If you use a hole saw go really slow.  The plastic will heat up in a hurry and gum up the cutting edges.  I have an old hand drill I use for putting holes in.  Even on slow speed the power drill gets gummed up and then starts to make the hole bigger.

[DeepSOIC 0]

i'm happy to report that the advice for slicing worked absolutely beautifully! Though i might have to reprint it, as i made it a bit too tight.

 

I used a nail drill with a small fast-spinning ceramic burr to melt-mill out the wall (and then cleaned the edge up with a polishing rubber wheel).

[GregValiant 1,351]

That looks pretty darn good.  Spherical prints are always tough.

Because the printer is so accurate I tend to make tolerances too tight as well.

I don't know if you have used these or not but places like McMaster Carr carry brass "push nuts" for plastics.  You stick them in the hole (usually a tapered hole) and push them in with a hot soldering iron.  These are #6-32 (about an M4).