Thursday 4 January 2018

3D printing and Musical instruments

3D Printed Electric Violin and Cello
    Over the Christmas season my family discovered some of The Piano Guys music videos and I remembered coming across the O'Cello & Mina Violin files, so I got some transparent PLA and started printing the parts. The designers intended for the parts of both projects to be printed on a standard i3-type printer, but I ended up using the Mega Kossel instead. 


Mina Violin neck freshly printed
Printing the Mina Violin body on the Mega Kossel
   As you can see, printing some of the parts needed some creative positioning of the parts, the lower body of the violin was particularly tricky, I ended up standing it on end, rotated by 30° onto one side and tilted back by 10° to get it to fit. After printing, some cleanup was needed, mostly stripping support material and stringing off, but on the violin the fingerboard came out a bit rough, so I sanded it down smooth then removed the heat induced scarring, as sanding PLA tends to mess up the finish.

Sanded PLA fidget cube
     The solution to the scarring issue is to take a heat-gun and run it lightly over the surface, don't pause in one place or you'll melt the print, and after a few passes the colour will reset and be indistinguishable from a freshly printed surface in colour. I'm using a light-duty 'art & craft' gun, but for the more industrial models you'll want to stick to the low setting, the higher one's will just wreck the print.

Heat-gun from Opus Art Supplies


Heat-treating before (bottom of cube) and after (top of cube)
Finished cube, note the distortion on the thin sections from overheating
    With the printing finished, the next step was sourcing the non-printed parts, I ended up using these piezo pickups from Amazon.ca instead of the default ones on both the violin and cello because the original ones are only available on Amazon.com and don't ship to Canada. The tuning pegs were these ones for the violin, and these for the cello. The strings are D'Addario Prelude for the cello and Thomastik Dominant for the violin, both bough from the local music store. All the fasteners were easily found at the local hardware store along with the structural threaded rods, 5/16" for the Violin and 7/16" for the Cello.

Mostly assembled O'Cello
Stringed O'Cello with Viola bow for scale
     After all that, the actual assembly was fairly straightforward, and they both sound surprisingly good, the O'Cello actually producing a decent level of sound even without the amplifier. The Mina violin turned out to produce a decent level of sound when played with a viola bow, I'm guessing the extra weight compared to a violin bow helps produce more volume of sound? Regardless I'm happy with how both turned out.

Completed Mina violin with pickup