FINALLY DONE!!!

I’m so happy I finally finished! I had to add an extra support inside, just underneath the bridge because there was way too much shear force on the top piece of acrylic.  Before I added the support, the top piece was sagging and I think I heard something crack..but nothing visible.  The epoxy looked really messy, so i decided to fog everything with sandpaper or it would have looked rather ugly.

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Things I could improve on:

1. The scroll is a bit flimsy.  When I was tuning it, I could feel the torsion (especially towards the top).
2. There are scorch marks inside, because in order to put in that extra support underneath the bridge, I had to laser the entire violin (since it was already glued together).  The speed setting was a bit slow so it ended up burning the inside of the bottom piece a bit.
3. Next time, I don’t plan on using glue.  For a MechE, it’s not really professional, it can’t be taken apart like screws can, and it’s just messy and a hassle to deal with.
4. I’ll probably purchase acrylic that’s more easily machine-able.  As mentioned in an earlier post, the first time I tried to widen the peg holes with a drill, the acrylic snapped.
5. I don’t think I’ll make another completely clear one in the future (this one was fogged).  All the wires and soldering inside is rather unattractive and I’d rather spend more time on the form than trying to hide the messiness inside.

Other Comments:

1. I’m glad I changed the neck design.  No sign of too much moment on the neck :)
2. Sound-wise, it’s pretty good!  When it’s not turned on, it’s a bit soft, but not shrill or plastic-sounding.
3.  The tone control has an interesting effect.  When turned up, it sounds sharper and more shrill.  I tapped my finger against the bridge with the tone at 10 and it sounded like high heels.
4. With the tone at 1, everything sounds more dulled and mellow.  Fingers tapping against bridge sounds like business shoes.

I’ll take more/better pictures soon! Gotta study for finals :(

Progress on the Neck

When I was trying to machine the neck to make the peg holes bigger, all the pieces snapped because my drill speed wasn’t fast enough :( That’s why the neck is missing some pieces in the post right before this.

I edited the laser cutter files for the neck and added another 1/8 inch layer of support to each side of the scroll. Here is the neck so far:

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I need to do a lot of filing/sanding, but since the Hobby Shop isn’t open for Thanksgiving, I’m going to take this time to work on my web portfolio/pdf portfolio a bit.  Also, the acrylic is really slippery, and I’m going to need more friction against the pegs to keep the pegs from turning when the violin strings are applying torque. Maybe I’ll spray on some glossy spray paint (tends to be a bit sticky) or just lightly sand it. The pegs need to be trimmed too (right now they’re too long).

Also, congress declared pizza sauce a vegetable? Whaa…

Laser-cut Acrylic pieces!

Here they are :) I have to do a lot of machine/hand work to smooth things out, and drill additional holes for the different parts of the pickup.  Also changed the neck design so it’s stronger, but I’m going to have to round it after gluing it together.

Right now, I’m trying to orient the circuit/battery/output  so that it doesn’t look out of place or messy.  It’s kind of difficult, since it’s clear and you can totally see everything inside.

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Fixing up the CAD

Made a lot of minor additions/changes and made the neck a lot thicker.  Also decided that I’m going to have to round the neck myself, since the previous method of using cross sections for the neck wasn’t very comfortable.

The acrylic finally arrived! I just have to lay everything out in illustrator before I laser.

Foam Core Prototyping

After laser-cutting out of foam core, I assembled everything with wood glue.  However, there are a few things I need to fix before I can laser cut out of acrylic:

1. neck doesn’t go into the body enough.  I’m afraid of the joint between the neck and body breaking due to tension from the strings.  I think the neck needs to go about another 1/4 inch deeper into the violin body.

2. The place where the fingerboard is supposed to go isn’t high enough off the body.  This will create a problem when playing on the E string (highest string) because the bow will hit the body of the violin a lot and it will be annoying.

3. I’m worried about the neck breaking right where it’s the thinnest, but the ebony fingerboard should prevent it from doing that.

If there are any other improvements that you think could be made, please don’t hesitate to tell me!

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Done With First Prototype CAD!!

Also rendered it :D Geoff (from Ideation Lab) is going to help me with foam core laser cutting tomorrow!

CADing Violin01 Body

I started out by CADing a violin body outline template and then using that to extrude the violin body for my first prototype.  It was a pain because I had to do a lot of measuring and tracing, and then draw everything with the spline tool, and SolidWorks isn’t a good program to use if you want curves.

This is going to be one that is clear and has acoustic properties.  The slot on top is for the pickup.  Still working on the neck..

Acrylic

I found this list of sizes/prices on McMaster-Carr for “Optically Clear and Colored Cast Acrylic. It can get pretty pricey..yikes.  Since the body is longer than 12 inches, I’ll need one of those 12″X24″ pieces.  I’ve started to CAD but I’m trying to minimalize the amount of acrylic I’ll need.

12″ × 12″
0.060″	+0.015″, -0.019″	8560K171	$3.93
0.080″	+0.014″, -0.020″	8560K181	4.37
0.118″	+0.015″, -0.025″	8560K191	6.41
0.125″	+0.015″, -0.025″	8560K239	8.53
0.177″	+0.017″, -0.033″	8560K211	8.95
0.236″	+0.020″, -0.040″	8560K221	11.50
0.250″	+0.020″, -0.040″	8560K354	14.61
0.354″	+0.025″, -0.055″	8560K591	17.07
0.472″	+0.025″, -0.065″	8560K242	22.36
0.500″	+0.025″, -0.065″	8560K265	26.59
0.708″	+0.030″, -0.080″	8560K361	31.92
0.985″	+0.023″, -0.087″	8560K371	37.01
1.000″	+0.023″, -0.087″	8560K321	47.15

12″ × 24″
0.060″	+0.015″, -0.019″	8560K172	7.07
0.080″	+0.014″, -0.020″	8560K182	7.92
0.118″	+0.015″, -0.025″	8560K192	11.51
0.125″	+0.015″, -0.025″	8560K257	14.83
0.177″	+0.017″, -0.033″	8560K219	17.79
0.236″	+0.020″, -0.040″	8560K222	20.99
0.250″	+0.020″, -0.040″	8560K355	25.41
0.354″	+0.025″, -0.055″	8560K593	24.15
0.472″	+0.025″, -0.065″	8560K243	40.64
0.500″	+0.025″, -0.065″	8560K266	46.24
0.708″	+0.030″, -0.080″	8560K362	58.38
0.985″	+0.023″, -0.087″	8560K372	61.69
1.000″	+0.023″, -0.087″	8560K322	81.99

Running into some trouble..

I’m running into some difficulties with the fingerboard angle and also the connection between the neck and the scroll..

On an acoustic violin (and the reference electric violin) the fingerboard and neck are angled upwards, so it’s not parallel with the body. Originally, I wanted to have it flat against the body, but I realized that it would mean the bridge would have to be half the height, which will decrease the sound quality.

I’m still brainstorming ways to connect the neck to the scroll as well..and how much of the original curves I want to keep. Even on an electric violin, the neck and scroll is one piece shaped out of wood (and painted over), so it’s going to be somewhat of a challenge trying to do it out of extruded 2D pieces of acrylic.

Reference Electric Violin

I was very lucky to borrow an electric violin from someone..so I opened up the back to gain a better understanding of how much wiring it would require (:
(pics bellow)

Since the wiring is more complicated that I had previously thought, I decided to stay with a online-ordered basic piezo pickup with 1/4″ output jack (the same one I used for my electric ukulele) so I don’t have to wire anything.  This will also be a passive pickup, which means it doesn’t require an extra battery, and it won’t have a volume or tone control knob /:

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