Printing marimba bars
I am trying to print a marimba. I have the first bar and resonator printed. I was able to find the zero node points. But the PLA I am using is not hard enough, so the length of the tone is too short.
What is the hardest (wood-like) filament? I suspect it will be one of the carbon-filled, but not sure which one.
Best Answer by Diem:
You're looking for a high Young's modulus. PLA is actually one of the harder printable plasics.
The base problem is that 3D printing solid blocks is not very easy at 100% infill but any lower percentage kills the resonance.
For some instruments you can get away with just printing multiple perimeters, woodwind is the easiest:
You might try experimenting with metal-filled PLA for greater density. Carbon-fibre filled filament will quickly get very expensive to print.
A hybrid instrument might be more playable, printed body and mounts with traditional tone-bars.
Cheerio,
RE: Printing marimba bars
Of materials I know, the highest tensile modulus is GreenTec Pro Carbon; so, it has a high storage modulus, whether it has a low loss modulus is another question entirely.
RE: Printing marimba bars
You're looking for a high Young's modulus. PLA is actually one of the harder printable plasics.
The base problem is that 3D printing solid blocks is not very easy at 100% infill but any lower percentage kills the resonance.
For some instruments you can get away with just printing multiple perimeters, woodwind is the easiest:
You might try experimenting with metal-filled PLA for greater density. Carbon-fibre filled filament will quickly get very expensive to print.
A hybrid instrument might be more playable, printed body and mounts with traditional tone-bars.
Cheerio,
RE: Printing marimba bars
Thank you Deim!
I looked up the Young's modulus (Chem E, not Mechanical E) and found it very informative. Looks like carbon filled might be good, but even higher than wood! My trials in PLA, which do give good sound, but short lived tone. Articles on making a marimba stress sanding the blocks to have no irregularities on the surface (not sure why), so will use a smooth printing plate rather then the Powder-Coated plate i print on. thank you for your comment.
I assume those recorders are yours. I need to do that too! Have done ocarina's and ceramic flutes.
RE: Printing marimba bars
@bobinatlanta
Articles on making a marimba stress sanding the blocks to have no irregularities on the surface (not sure why)
I presume the irregularities cause reflections in the wave-fronts and muddy the sound. Perhaps worth experimenting for interesting tones.
@xanthe
whether it has a low loss modulus is another question entirely.
Probably depends heavily on the host plastic. I would expect it to be tweakable by varying the shape, eg hollow out the underside in places. Might be difficult to maintain pitch if you go that way.
Cheerio,
RE: Printing marimba bars
Here is another method to try:
I use up my scrap plastic; failed prints, support, obsoleted prototypes etc. by making simple panels that other makers sometimes find useful in their projects.
Below is a typical one, ca 150gm 22x16x0.35 cm. I scatter the waste, PLA in this case, onto a rectangular, non-stick baking tray and 'bake' for 10 minutes in an electric oven at 100 degrees C.
So I picked this one up and tapped it. It resonates surprisingly well...
If you go this route I leave it up to you how you work it - but if it fails, well, it was waste material anyway.
Cheerio,