3D Printed violin Project Part 2

I liked the design of the Hovalin violin. However it was too quiet, did not sound good, took too many parts to print, extremely heavy, and needed a redesign. I thought that I could make it better my self and release it to the community. My goal is to improve sound quality, sound volume, and simplicity.

Here were the results:

My first idea was to replace the Hovalin bridge with a traditional wooden bridge or design a thinner 3D printed bridge. The original design has a dense bridge built into the body. I was thinking that it was dampening the sound due to so much material. The bridge is the most crucial component to a violin because it transfers the sound energy from the strings to the body amplifying the sound. I began by shaping a wooden bridge using an X – Acto knife and a belt sander to fit the Hovalin body profile. However the geometry of a traditional wooden bridge was not compatible to fit the Hovalin. I then designed a 3D printed bridge. After testing the difference between the new and old bridge design it seemed to not do much to affect the sound. This was good because the 3D printed bridge was to slippery and moved when played. Having an immobile bridge is a huge advantage.

• 

• 

• 

• 

I then moved on to editing the body of the violin. I imported the STL file as a mesh in Fusion 360 having to convert it to editable geometry. A violin is a complex shape and has over 100 thousand facets. I had to remove a high percentage compromising the integrity of the model to prevent Fusion 360 from crashing. Once converted I could only edit the model by drawing sketches and extrude cutting. This proved to be a very tedious and inaccurate way of editing the model. I soon found the original Fusion 360 files on Hovalin’s website. You can import the file allowing you to have access to the whole design history. This gave me the ability to accurately change specific parts of the design. I now had total access to the violin design.

• 

• 

• 

I got to work on the CAD first taking out the dove tail joint slot between the top and mid body. The dove tail joints are huge walls inside of the violin body that traps the sound. Thinking that removing this features will improve both sound quality and volume. After removing the dove tail joint I could combine both the mid and top bodies together. At a height of 209.6 mm I was just lucky enough to be able to print it on a Prusa i3 MK3s.

• 

• 

• 

• 

• 

I brought my ideas to a luthier at Hoffman Strings and asked him for suggestions on what I was trying to accomplish. A luthier is a professional violin maker. He gave me some tips and ideas on how to approach it. Having not worked on a plastic violin before it was hard to know for certain if some changes would help for the better or worse. Plastic does not resonate as well as wood creating the tinny and quiet sound.

To finish the bottom body I needed to relocate the mid body fins to the bottom. The fins help add strength and is a guide when putting the violin together. I had to create custom support for the new fins due to being very small and protruding out of the bottom. I needed a greater surface area so the violin would not fall off the bed when printing. The support is an offset from the body at a tolerance of .333 mm. This gives the support the ability of staying stuck while printing. When cooled and taken off the bed you can easily take off the support. Lastly adding a custom lighting bolt to the Hovalin logo.

• 

• 

• 

• 

• 

• 

I then began redesigning the neck to eliminate the need for guitar tuners. The four tuners weigh 120 grams which is insane! A traditional violin weighs 400-450 grams. The Hovalin violin weighs a whopping 700 grams. This is extremely heavy for a violin. I wanted to design a peg box like a traditional violin. While at a luthier shop I was told to try and use galaxy pegs. Galaxy pegs have a gear inside moving only the head of the peg and the shaft. A violin pegs job is to tighten the string to create the right pitch and stay in tune. The string wraps its self around the shaft making it tighter. This would solve the issues of weight, look better, and be more efficient. However I would have to redesign the peg box and a set of galaxy pegs cost $150. Which was not Ideal for a cheap violin.

I designed the neck for the violin using a traditional peg box and scroll. This gives the violin a more traditional appeal. This is still in progress.

• 

• 

• 

I wanted to try and design my own galaxy pegs using 3D printing and LEGOs. I can not reach the level of detail needed at such a small scale using a 3D printer. I decided that a possible solutions is to use LEGO axles and shafts combined with 3D printing. I started with a concept sketch of what the peg would look like. I then found my old box of LEGOs and dumped it out to find the necessary pieces. I put together a rough model with an axle, axle holder, axle pin, and wheel. This is still in progress.

• 

• 

• 

• 

In all traditional violins there is a logo inside in view when looking through the f-hole. The logo says who made it and the year it was made. I designed my own using Illustrator.

• 

• 

There are still several variables to consider when 3D printing. I am currently running a sound analysis to determine if more perimeters and less infill or vice versa affect the sound for the better. The changes that I have made has drastically impacted the sound making it louder and better sounding.