The one instrument I would have my bodyguards play as we sauntered down the street is a violin. They’re sound is just wonderfully ominous and mysterious, while equally enchanting and… mysterious.
After building a traditional wooden Guarneri-style violin, Brian Chan, an Engineer at Formlabs, took it upon himself to design a functional (and quite good sounding) 3D printed violin. Now, you may think, big F-hole deal– print the body in one go and DONE. But no, with the printer’s build area and size of the violin, even the body had to be designed and printed as separate parts. And Brian, with his suave violin making ways, approaches the build of this a completely different way that you might imagine.
First, if you know about string instrument construction, you know every bit, from the tonewood and lining to any support or bridge, matters. It’s difficult to think of how the body could be constructed in multiple pieces and still sound like anything more than a bucket with strings. So, when I saw this exploded view of the final version, I had my bodygaurds stop and scream, “Great gobs of Stradivari shellac!” …with a slight vibrato at the end.
Here’s what Brian says about the process:
I wanted to design a 3D-printed violin to have the same internal structure: a hollow shell with the soundpost near one side of the bridge, and a strengthening bar of material along the inside of the front. Later, I would experiment with the dimensions of these various elements, but it was important to get the basics right.
And the modeling:
Because these surfaces are based on a grid, they can have up to four natural singularities, which would correspond to the four corners of a rectangular grid. Luckily, the violin body has four corners, while the rest of the boundaries are smooth. In Onshape, I was able to define this shape as a loft, with corners of the cross-sections located at the corners of the violin. To constrain the loft to the right shape, I used the C-shaped outlines and the centerline contour as guides. These cross-sections and guides are based on actual outlines of a Stradivarius violin, which can be found in the same book I used to construct the traditional Guarnerius violin.
And the printing:
I printed the prototypes using the Form 2 and Formlabs’ White, Black, and Tough Resins. Stereolithography (SLA) made sense for this project because the violin needed to be strong enough to withstand several different directional forces, and SLA parts are isotropic, meaning that they are equally strong in every direction. Also, the complex geometry of the instrument demanded tight tolerances for both small and large features, which the Form 2 was able to print consistently.
Through it all, Brian constructed five different 3D printed prototypes. The final version is made up of 26 3D-printed parts which can be printed in five overnight prints on a Form 2. The other bits can all be easily bought a your local Violins R Us.
How does it sound? The violin parts in the video below were recorded using the 3d printed violin as played by violinist Rhett Price:
I’m not sure if a 3D printed white resin violin would be accepted among the purists in the Boston Philharmonic, but the sound coming from this is good enough to last through at least one session of intense outdoor unamplified playing by a professional violinist wiggling about.
You can read the entire breakdown on the process at the Onshape blog. The 3D print files are available to download via Pinshape. Grab it here. You can also request a free sample part of Formlab’s white resin by visiting the Formlabs site here.
