3D Printed speakers - Unlock impossible designs compare to conventional

[MCH]

Good questions. The water is part of the chemical reaction in the plaster that makes it set, so there are no volatiles or off-gasses. The reaction is exothermic though so maybe pour in parts for a large enclosure in case it heats up enough to deform/melt the plastic.

I don't expect cracks to be an issue. The wood glue is added for the purpose of making the dried plaster less crumbly and its encased in the plastic walls with the gyroid fill in between to lend its support too. If you were to drop a dried speaker, then it might crack. I can CT again after "x" amount of time to confirm this theory though.

Water is a volatile, and you have quite some there. I don't know what exact products you used so it is very difficult to predict if it is going to shrink or crack. Well, it would be difficult even knowing, being a mixture, and will also depend on the volume etc etc.
It is just a suggestion to have into account.

 

[DVinylfan]

Great thread.
The obvious question being: can 3D printed speakers deliver 3D sound?
Since the advantage of 3D printing is to produce more complex designs than traditional production methods, what greater complexity in speaker design is required to improve/progress speaker designs when compared to those designed and manufactured with non-3D printed methods, e.g. B&W Nautilis?

 

[celstark]

I've started doing some tests while considering a 3d printed speaker build. The test box shape is meant to emulate what part of a speaker enclosure might look like with 19mm walls and a flat bottom with hollow space in the center.


I have access to a CT scanner with my job so I took a scan of the dried plaster-filled box. This gives us a comprehensive view of the internal structure of a filled 3d printed enclosure. We can see if there are any air bubbles or areas where the plaster filler didn't get to. The CT also provides density information on the materials in the scan.

Results: The CT images are below. The plaster/glue mixture flowed well within the hollow walls and there were only a few small air bubbles. In the 3d view (top right) you can see the plaster volume and there are no big gaps or areas where the plaster/glue mixture did not reach (I didn't fill the walls up all the way so its irregular on top). The plaster/glue mixture averages about 850HU (Hounsfield Unit is a relative density scale used in CT. web search for more info). The PLA+ is about 700HU.

OMG, I love this! I'd done some resonance testing using a contact mic to examine PLA vs. PETG vs. TPU and to test some infill setups. The mics, meant for things like violins and such, are cheap and good at least for relative measures. I did 5 measure / remove / reapply passes to get a decent stable curve. BTW, your CT will be loads better than my MRI for this, but LMK if we need MR.

 

[somebodyelse]

Water is a volatile, and you have quite some there. I don't know what exact products you used so it is very difficult to predict if it is going to shrink or crack. Well, it would be difficult even knowing, being a mixture, and will also depend on the volume etc etc.
It is just a suggestion to have into account.

Assuming the correct ratio of water to plaster of paris is used, the water is all consumed in the reaction. It doesn't shrink or crack which is what makes it good for casting of or in molds.

 

[bmc0]

Assuming the correct ratio of water to plaster of paris is used, the water is all consumed in the reaction.

Not true except for a few specialty gypsum cements (e.g. USG Drystone). The chemical water requirement is approx. 18 parts per 100 parts plaster by mass, but standard plaster (β-gypsum without water reducing additives) needs 70 parts water or more for a pourable consistency.